Diagnosis of dementia by vascular magnetic resonance imaging

Abstract

To provide a method of diagnosing a likelihood of onset or progression of Alzheimer's disease and related dementias (ADRD) in a subject.SOLUTION: A method requires determining vascularization changes in different regions of a brain on the basis of a quantitative cerebral blood volume (qCBV) map of the subject's brain. The qCBV is obtained from one or more quantitative ultrashort time-to-echo contrast-enhanced (QUTE-CE) MRI images of the brain. A method of treating a subject having ADRD is provided. Diagnostic markers for onset and progression of Alzheimer's disease are also provided.SELECTED DRAWING: None

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 62 / 711,251, entitled “DIAGNOSIS OF DEMENTIA BY VASCULAR MAGNETIC RESONANCE IMAGING,” filed on July 27, 2018, the disclosure of which is incorporated herein by reference.

[0002] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with Government support under Grant No. EB013180a awarded by the National Institutes of Health. The Government has certain rights in this invention. [Background technology]

[0003] Age-related dementia is a global health problem, affecting more than 50 million people worldwide with estimated costs exceeding $818 billion (WHO Fact Sheet, Dementia, 2017). Dementia affects more than 8 million older adults in the United States alone with total costs of $277 billion (Alzheimer's Disease Facts and Figures, 2018). With age comes the risk of Alzheimer's Disease (AD), a degenerative brain disorder that is rated as the leading cause of dementia (Wilson, RS et al., 2012; Barker, WW et al., 2002). Aging also carries the risk of cerebrovascular disease, traditionally considered to be the second leading cause of dementia (Banerjee, G et al., 2015; Roman, GC et al., 2004). However, evidence is accumulating that cerebrovascular disease plays an important role in AD neurodegeneration and dementia (Schneider, JA et al., 2007; Wharton, SB et al2011) and may be the most common form of dementia in older adults (Gorelick, PB et al., 2011; Roman, GC et al. 2001). This distinction is important because cerebrovascular disease may be a key factor in the pathophysiology of AD (Kalaria, R. N & Ballard, C., 1999). Thus, early detection and treatment of cerebrovascular disease may reduce the risk of AD with age. Early biomarkers of dementia and AD could save the current US population as much as $12.72 billion to $92.56 billion annually from 2025 to 2050 (Alzheimer's Disease Facts and Figures, 2018). Summary of the Invention [Problem to be solved by the invention]

[0004] The exact biochemical mechanisms underlying AD remain to be elucidated, and therefore there is a compelling need to develop quantitative and reliable physiological biomarkers for the diagnosis, prognosis, and treatment of AD and related forms of dementia. [Means for solving the problem]

[0005] Provided herein is a method of diagnosing the likelihood of onset or progression of Alzheimer's disease and related dementias (ADRD) in a subject. In this method, a measurement technique is used to quantify vascularity throughout the brain using an ultra-short time-to-echo (UTE) pulse sequence of magnetic resonance imaging (MRI) and an intravascular contrast agent. This technique allows for the measurement of blood volume per unit volume in an anatomical region of the brain. This allows for the determination of whether a particular anatomical region of the brain is hypervascularized or hypovascularized. According to one aspect of the techniques presented herein, a greater number of hypervascularized sites compared to hypovascularized sites indicates a greater likelihood of onset of ADRD. A greater number of hypovascularized sites compared to hypervascularized sites indicates a greater likelihood of progression of ADRD. In another aspect of the present technology, a greater amount of brain hypervascularized sites than hypovascularized sites indicates a higher likelihood of ADRD onset, while a greater amount of hypovascularized sites than hypervascularized sites indicates a higher likelihood of ADRD progression. In yet another aspect, an increase in the ratio of hypervascularized sites to hypovascularized sites indicates an increased likelihood of ADRD onset, while a decrease in this ratio indicates an increased likelihood of ADRD progression. Similarly, in another aspect of the technology, an increase in angiogenesis compared to normal subjects indicates an increased likelihood of ADRD onset, while an increase in hypovascularization compared to normal subjects indicates an increased likelihood of ADRD progression. Furthermore, dynamic measurements using this technique can be performed by utilizing short time scales to observe normal oscillations of physiological blood volume modulation for purposes of determining brain region connectivity, or by providing measurements of neurofunctional modulation, e.g., blood volume after hypoxia, which can provide vascular reserve to assess cerebrovascular reactivity (CVR). Diagnostic markers for the onset and progression of ADRD are also provided herein.

[0006] Using this measurement technique, a trend towards hypervascularization was observed in the APOE4 preclinical rat model of ADRD before disease onset (7 months of age). This trend was mainly related to the microvasculature, suggesting that increased capillary or small blood vessel density may be a coping mechanism for metabolic dysfunction in dementia. A trend towards hypovascularization was observed (in 2-year-old rats) in the APOE4 preclinical rat model of ADRD, both in terms of small vessels (microvasculature or capillary density) but also in terms of average vascularity (including large vessels in the calculation). These observations are consistent with evidence from human MRI studies in which human APOE4 carriers showed hyperperfusion before ADRD onset and hypoperfusion was observed after ADRD onset (Kim, SM et al., 2013).

[0007] In a CO2 challenge breathing model where air was replaced with 95% air and 5% CO2, the response in the rat APOE4 model of AD was substantially more significant than the anatomical wild type (WT) (approximately 95 / 174 anatomical sites vs. 25 / 174 sites with significant change p<0.05).

[0008] CO2 challenge produced a durable response in an APOE4 genetically modified rat model of ADRD. WT rats recovered almost immediately from the CO2 challenge, whereas APOE4+ rats did not recover at all. Furthermore, reapplication of the challenge resulted in an expanded response in APOE4+ rats (now approx. 125 / 174 sites significantly different, p<0.05), whereas WT responses were only approx. 20 / 174 sites. Thus, a hypersensitive response was found in 2-year-old APOE4+ rats. In the latest stages of pre- or dementia in humans, it can be expected that a hypoxic challenge may not result in dilation of the vasculature if the vascular reserve is already utilized at rest, as seen in Moyamoya disease. It is known that the CVR is low, although it involves a large amount of hypervascularization, since the reserve is constantly utilized.

[0009] Patterns of microvasculature and mean vascularity measurements, such as by anatomical site, can be used to identify statistical variance in normal aging. Vascular progression can be quantitatively assessed by anatomical site of the brain. Thus, the vascular pathophysiology of specific brain sites and their role in ADRD can be evaluated. Quantification of sites also allows for network-level analysis. Mean vascularity is simply calculated as the average of regions of interest (ROIs), and the distribution mode of each ROI can be used as a proxy for microvascularity.

[0010] The trend from hypervascularization to hypovascularization from disease onset to progression has not been demonstrated so far. The demonstration of the trend from hypervascularization to hypovascularization here is made possible in part by using the measurement techniques described above. The vascular pathogenesis of dementia has been poorly understood so far, and the trend described herein provides a new biomarker for early detection of ADRD, which accounts for 60-70% of dementia, or for early detection of dementia in general.

[0011] Existing methods for detecting brain changes occurring before the onset of dementia require a large number of groups / subjects for relevant statistics, and therefore are not suitable for early detection.These methods usually use functional MRI (fMRI), amyloid positron emission tomography (PET), or tau PET imaging.In contrast, in the method described herein, detection is possible by a single measurement. Thus, in some aspects of the present technology, a method for detecting the increased probability of developing or progressing Alzheimer's disease or ADRD in a subject is provided.In some aspects, the method includes:(a) obtaining one or more quantitative ultrashort time-to-echo contrast-enhanced (QUTE-CE) MRI images of the subject's brain, thereby usually obtaining pre-contrast and post-contrast images;(b) obtaining B1+ and B1- field measurements that are used to obtain more accurate results;(c) creating a quantitative cerebral blood volume (qCBV) map of the subject's brain from the image incorporating B1 measurements;(d) determining the hypervascularized and hypovascularized areas in the subject's brain based on the comparison of the qCBV map obtained in step (c) with a predetermined qCBV map representing a healthy subject's brain; and(e) diagnosing the likelihood that the subject will develop ADRD, the development of ADRD, or the progression of ADRD based on the analysis of the hypervascularized and hypovascularized patterns.

[0012] A hypervascularized region is one in which the intravascular blood volume is increased compared to the same region of a normal brain of a similar age under similar physiological conditions. A hypovascularized region is one in which the intravascular blood volume is decreased compared to the same region of a normal brain of a similar age under similar physiological conditions. The boundaries of the regions can be freely selected or can be defined by standard anatomical definitions.

[0013] In a further aspect, the method includes (a) obtaining one or more quantitative ultrashort echo time contrast imaging (QUTE-CE) MRI images of the subject's brain, both pre-contrast and post-contrast; (b) generating a quantitative cerebral blood volume (qCBV) map of the subject's brain from the images; (c) determining sites of hypervascularization and hypovascularization in the subject's brain based on a comparison of the qCBV map obtained in step (b) with a predefined qCBV map representative of a healthy subject's brain; and (d) diagnosing the likelihood that the subject will develop Alzheimer's disease, the onset of Alzheimer's disease, or the progression of Alzheimer's disease based on an analysis of the hypervascularized and hypovascularized sites.

[0014] In another aspect, a diagnostic marker, or set of diagnostic markers, for the development of ADRD in a subject is provided. Suitable diagnostic markers include hypervascularization in one or more regions of a subject's brain selected from the group consisting of ventral tegmental area, crus linearis, reticular tegmental nucleus, crus nucleus, havenula nucleus, median raphe nucleus, dorsomedial tegmental area, dorsal raphe, pontine nuclei, raphe magnus, ventral subiculum, motor trigeminal nucleus, copula of the pyramis, pontine reticular nucleus caudalis, pontine reticular nucleus oralis, trapezoid body, subiculum dorsalis, parabrachial nucleus, reticular nucleus midbranchii, retrosplenial caudal cortex of corpus callosum, pedunculopontine tegmental area, red nucleus, subcoeruleus subcoeruleus, PCRt, inferior colliculus, facial nucleus, 9th cerebellar lobule, magnocellular reticular nucleus, trigeminal main sensory nucleus, entorhinal cortex, trigeminal nerve root, visual cortex 1, 10th cerebellar lobule, prelimbic cortex, precuneiform nucleus, inferior limbic cortex, superior colliculus, solitary tract nucleus, and periaqueductal gray thalamus. Hypervascularization can be determined, for example, by comparing a qCBV map of the subject's brain generated from one or more images of the subject's brain obtained using one or more QUTE-CE MRI images of the subject's brain, and comparing the qCBV map to a preferably predetermined qCBV map representing the brain of a healthy subject, preferably of a similar age and physiological condition.

[0015] In a further aspect, a diagnostic marker or set of diagnostic markers for the progression of ADRD in a subject is provided. The diagnostic markers include ventral tegmental area, crus linearis, reticular tegmental nucleus, crus nucleus, havenula nucleus, median raphe nucleus, dorsomedial tegmental area, dorsomedial raphe, pontine nucleus, raphe magnus, ventral subiculum, motor trigeminal nucleus, copula of the pyramis, pontine reticular nucleus caudalis, pontine reticular nucleus oralis, trapezoid body, subiculum dorsalis, parabrachial nucleus, reticular nucleus midbranchii, posterior caudal cortex of the corpus callosum, pedunculopontine tegmental area, red nucleus, subcoeruleus subcoeruleus, PCRt, inferior colliculus, facial and hypovascularization in one or more regions of the subject's brain selected from the group consisting of: the 9th cerebellar lobule, the gigantocellular reticular nucleus, the trigeminal main sensory nucleus, the entorhinal cortex, the trigeminal nerve root, the visual 1 cortex, the 10th cerebellar lobule, the prelimbic cortex, the trigeminal main sensory nucleus, the subtidal cortex, the superior colliculus, the solitary tract nucleus, and the periaqueductal gray thalamus, wherein hypovascularization can be determined by comparing a qCBV map of the subject's brain generated from one or more images of the subject's brain obtained using one or more QUTE-CE MRI images of the subject's brain and comparing the qCBV map to a preferably predetermined qCBV map representing the brain of a healthy subject, preferably of a similar age and physiological condition.

[0016] In yet another aspect, a diagnostic marker is provided for the development of a diagnostic marker in a subject, comprising hypervascularization of one or more regions of the subject's brain selected from the group consisting of the paraventricular nucleus, ventral subiculum, dorsal raphe, visual secondary cortex, dorsomedial tegmental area, inferior colliculus, motor trigeminal nucleus, primary somatosensory cortical trunk, triangular septal nucleus, ventromedial striatum, and lateral preoptic area, wherein hypervascularization can be determined by comparing a qCBV map of the subject's brain generated from one or more images of the subject's brain obtained using one or more QUTE-CE MRI images of the subject's brain, and comparing the qCBV map to a predetermined qCBV map representative of a healthy subject's brain.

[0017] In a further aspect, a diagnostic marker or set of diagnostic markers for the progression of a diagnostic marker in a subject is provided.Suitable diagnostic markers include hypovascularization of one or more regions of the subject's brain selected from the group consisting of the paraventricular nucleus, ventral subiculum, dorsal raphe, visual 2ctx, dorsomedial tegmental area, inferior colliculus, motor trigeminal nucleus, primary somatosensory cortical trunk, triangular septal nucleus, ventromedial striatum, and lateral preoptic area, where hypovascularization can be determined by comparing a qCBV map of the subject's brain generated from one or more images of the subject's brain obtained using one or more QUTE-CE MRI images of the subject's brain, and comparing the qCBV map to a predetermined qCBV map representative of a healthy subject's brain.

[0018] Dynamic measurements in response to stress such as CO2 can be performed in clinical practice. Measurements of vascular reserve can therefore also serve as diagnostic markers. Metabolic dysfunction in disease states may include persistent responses to stress such as hypoxia, which may improve disease characterization and detection sensitivity.

[0019] The vascular diagnostic markers described herein can be used as biomarkers for early diagnosis, prognosis, prediction of cost of patient care, and drug development. Many clinical trials of ADRD drugs fail because endpoint characterization and treatment are initiated too late (after disease onset). Early detection allows for preventative care and planning.

[0020] The present technology further has the following aspects. 1. A method for diagnosing the onset or progression of Alzheimer's disease or related dementia (ADRD) in a subject, comprising: (a) obtaining one or more quantitative ultrashort echo time contrast imaging (QUTE-CE) MRI images of a subject's brain; (b) generating a quantitative cerebral blood volume (qCBV) map of the subject's brain from the images; (c) determining areas of hypervascularization and hypovascularization in the subject's brain based on a comparison of the qCBV map obtained in step (b) with a predefined qCBV map representative of a normal brain; and (d) diagnosing the likelihood of developing ADRD or progressing to ADRD in the subject based on the analysis of the hypervascularized and hypovascularized sites; The method comprising:

[0021] 2. The method of aspect 1, wherein in step (d), a greater number of hypervascularized sites compared to hypovascularized sites indicates that the development of ADRD has occurred in the subject. 3. The method of aspect 1 or 2, wherein in step (d), a greater number of undervascularized sites compared to hypervascularized sites indicates that progression of ADRD has occurred in the subject. 4. The method of any of aspects 1-3, further comprising repeating the method at a later time point, wherein a decrease in the number or extent of undervascularized sites found in step (d) at the later time point indicates progression of ADRD in the subject. 5. The method of any of aspects 1-4, further comprising repeating the method at a later time point, wherein an increase in the number or extent of hypervascularized sites found in step (d) at the later time point indicates progression of ADRD in the subject.

[0022] 6. The method of any of aspects 1-5, wherein the under- and / or hypervascularization is determined based on measurements of the microvasculature, capillary density, or average vascularity. 7. The method of any of aspects 1-6, wherein progression of ADRD is indicated in the subject, wherein the extent of hypo- and / or hyper-vascularization is indicative of the extent of progression of ADRD in the subject. 8. The hypervascularization is in the ventral tegmental region, crusted linea, reticular tegmental nucleus, crusted nucleus, havenula nucleus, median raphe nucleus, dorsomedial tegmental region, dorsomedial raphe, pontine nucleus, raphe magnus, ventral subiculum, motor trigeminal nucleus, copula of the pyramis, pontine reticular nucleus caudalis, pontine reticular nucleus oralis, trapezoid body, dorsal subiculum, parabrachial nucleus, reticular nucleus midbrain, posterior caudal cortex of the corpus callosum splenialis, pedunculopontine tegmental area, red nucleus, Any of the methods of aspects 1-7, in one or more regions of the subject's brain selected from the group consisting of the subcoeruleus, PCRt, inferior colliculus, facial nucleus, 9th cerebellar lobule, gigantocellular reticular nucleus, trigeminal main sensory nucleus, entorhinal cortex, trigeminal nerve root, visual 1 cortex, 10th cerebellar lobule, prelimbic cortex, precuneus nucleus, subtidal cortex, superior colliculus, solitary tract nucleus, and periaqueductal gray thalamus.

[0023] 9. The hypovascularization is in the following areas: ventral tegmental area, crusted linea, reticular tegmental nucleus, crusted nucleus, havenula nucleus, median raphe nucleus, dorsomedial tegmental area, dorsomedial raphe, pontine nucleus, raphe magnus, ventral subiculum, motor trigeminal nucleus, copula of the pyramis, pontine reticular nucleus caudalis, pontine reticular nucleus oralis, trapezoid body, dorsal subiculum, parabrachial nucleus, reticular nucleus midbrain, posterior caudal cortex of the corpus callosum splenialis, pedunculopontine tegmental area, red nucleus, Any of the methods of aspects 1-8, in one or more regions of the subject's brain selected from the group consisting of the subcoeruleus, PCRt, inferior colliculus, facial nucleus, 9th cerebellar lobule, gigantocellular reticular nucleus, trigeminal main sensory nucleus, entorhinal cortex, trigeminal nerve root, visual 1 cortex, 10th cerebellar lobule, prelimbic cortex, precuneus nucleus, subtidal cortex, superior colliculus, solitary tract nucleus, and periaqueductal gray thalamus.

[0024] 10. Any of the methods of aspects 1-9, wherein said hypervascularization is in one or more regions of the subject's brain selected from the group consisting of the paraventricular nucleus, ventral subiculum, dorsal raphe, visual 2 cortex, dorsomedial tegmental area, inferior colliculus, motor trigeminal nucleus, primary somatosensory cortical trunk, triangular septal nucleus, ventral medial striatum, and lateral preoptic area. 11. Any of the methods of aspects 1-10, wherein said hypovascularization is in one or more regions of the subject's brain selected from the group consisting of the paraventricular nucleus, ventral subiculum, dorsal raphe, secondary visual cortex, dorsomedial tegmental area, inferior colliculus, motor trigeminal nucleus, primary somatosensory cortical trunk, triangular septal nucleus, ventral medial striatum, and lateral preoptic area. 12. The method of any of aspects 1-11, wherein obtaining the QUTE-CE MRI image comprises introducing a paramagnetic or superparamagnetic contrast agent into the subject's brain. 13. The method of aspect 12, wherein the paramagnetic or superparamagnetic contrast agent is selected from the group consisting of iron oxide nanoparticles, gadolinium chelates, and gadolinium compounds. 14. The method of aspect 13, wherein the iron oxide nanoparticles comprise a material selected from the group consisting of Fe3O4 (magnetite), γ-Fe2O3 (maghemite), α-Fe2O3 (hematite), ferumoxytol, ferumoxide, ferucarbotran, and ferumoxtran.

[0025] 15. The method of aspect 14, wherein the iron oxide nanoparticles comprise ferumoxytol. 16. A method of treating ADRD in a human subject, comprising performing the method of any of aspects 1-15 to diagnose the onset or progression of ADRD in a human subject, and treating the human subject for ADRD. 17. The method of aspect 16, wherein the treating step comprises administering a cholinesterase inhibitor, such as donepezil, rivastigmine, galantamine, memantine; an antidepressant, such as citalopram, fluoxetine, paroxeine, sertraline, or trazodone; an anti-anxiety agent, such as lorazepam or oxazepam; or an antipsychotic, such as aripiprazole, clozapine, haloperidol, olanzapine, quetiapine, risperidone, or ziprasidone, or any combination thereof. 18. The method of aspect 16 or 17, wherein the step of treating the human subject comprises application of behavioral therapy, such as changing the environment, redirecting attention, avoiding conflict, providing rest, or monitoring one or more of pain, hunger, thirst, constipation, full bladder, fatigue, infection, skin irritation, and room temperature; and any combination thereof. [Brief description of the drawings]

[0026] [Figure 1A-C]Figure 1A-1C show representative images of QUTE-CE MRI raw intensity rendered with 3DSlicer. Figure 1A shows a pre-contrast image (before ferumoxytol contrast injection). Figure 1B shows a post-contrast image (after injection of ferumoxytol 14 mg / kg). Rendering parameters are comparable. Figure 1C shows the segmented brain of Figure 1B. Relevant parameters are as follows: 3D radial UTE; FOV 3x3x3 cm3; matrix mesh size 200x200x200; TE 13 μs; TR 3.5 ms; and θ = 20°, scan time = 8 min 22 s, two averages.

[0027] [Figure 2-1] Figure 2 shows the QUTE-CE MRI image analysis pipeline and biomarker measurements in Sprague-Dawley rats. Methodology: Top left image: Contrast-free and angiographic images are obtained before and after ferumoxytol injection, respectively. Note that the contrast in maximum intensity projection (MIP) images is mostly due to the presence of ferumoxytol at 7T, with blood flow effects limited to the periphery. Field corrections for coil sensitivity (B1) and flip angle distribution (B1+) are applied along with motion correction between pre- and post-contrast images. Middle left image: qCBV is calculated by cropping the brain and applying the corresponding formula with quantitative intensity values. Bottom left image: Regions are characterized by distributing 500,000 voxels in the brain into a 173-region atlas via co-registered affine transformation using EVA software (Ekam Solutions, Boston, MA, USA). Center image: Vascular atlas constructed in male Sprague-Dawley rats (9-10 weeks old, N=11) and (right) CO2 can was applied to measure vascular responsiveness. Of note, imaging was performed in awake but mechanically restrained rats to simulate the neurophysiological condition for clinical imaging experiments in the human brain. Therefore, the direction and magnitude of vascular changes during isoflurane anesthesia were also determined for rats (labeled "ISO").

[0028] [Figure 2-2] Figure 2 shows the QUTE-CE MRI image analysis pipeline and biomarker measurements in Sprague-Dawley rats. Methodology: Top left image: Contrast-free and angiographic images are obtained before and after ferumoxytol injection, respectively. Note that the contrast in maximum intensity projection (MIP) images is mostly due to the presence of ferumoxytol at 7T, with blood flow effects limited to the periphery. Field corrections for coil sensitivity (B1) and flip angle distribution (B1+) are applied along with motion correction between pre- and post-contrast images. Middle left image: qCBV is calculated by cropping the brain and applying the corresponding formula with quantitative intensity values. Bottom left image: Regions are characterized by distributing 500,000 voxels in the brain into a 173-region atlas via co-registered affine transformation using EVA software (Ekam Solutions, Boston, MA, USA). Center image: Vascular atlas constructed in male Sprague-Dawley rats (9-10 weeks old, N=11) and (right) CO2 can was applied to measure vascular responsiveness. Of note, imaging was performed in awake but mechanically restrained rats to simulate the neurophysiological condition for clinical imaging experiments in the human brain. Therefore, the direction and magnitude of vascular changes during isoflurane anesthesia were also determined for rats (labeled "ISO").

[0029] [Figure 2-3]Figure 2 shows the QUTE-CE MRI image analysis pipeline and biomarker measurements in Sprague-Dawley rats. Methodology: Top left image: Contrast-free and angiographic images are obtained before and after ferumoxytol injection, respectively. Note that the contrast in maximum intensity projection (MIP) images is mostly due to the presence of ferumoxytol at 7T, with blood flow effects limited to the periphery. Field corrections for coil sensitivity (B1) and flip angle distribution (B1+) are applied along with motion correction between pre- and post-contrast images. Middle left image: qCBV is calculated by cropping the brain and applying the corresponding formula with quantitative intensity values. Bottom left image: Regions are characterized by distributing 500,000 voxels in the brain into a 173-region atlas via co-registered affine transformation using EVA software (Ekam Solutions, Boston, MA, USA). Center image: Vascular atlas constructed in male Sprague-Dawley rats (9-10 weeks old, N=11) and (right) CO2 can was applied to measure vascular responsiveness. Of note, imaging was performed in awake but mechanically restrained rats to simulate the neurophysiological condition for clinical imaging experiments in the human brain. Therefore, the direction and magnitude of vascular changes during isoflurane anesthesia were also determined for rats (labeled "ISO").

[0030] [Figure 3A] FIG. 3A shows hypovascularization in 24-month-old wild-type (WT) versus APOE4 female rats. [Figure 3B] FIG. 3B shows vascular density-average in wild-type versus APOE4 female rats at 8 and 24 months of age. [Figure 3C] Figure 3C illustrates capillary density (or small blood vessel)-mode of wild-type female and APOE4 female rats at 8 and 24 months of age.

[0031] [Figure 4A] FIG. 4A illustrates a comparison of APOE4 and WT mean vascular abnormalities detected at 8 months. [Figure 4B] Figure 4B shows a comparison of APOE4 and WT microvascular abnormalities detected by site at 8 months.

[0032] [Figure 5A-B] Figure 5A is a graph of small vessel and total vessel vascular abnormalities at 8 months and 2 years, showing a trend toward vascular decline at 2 years. Figure 5B is a graph of CO2 loading demonstrating metabolic dysfunction involving CO2 channels in APOE4 and WT.

[0033] [Figure 6-1] Figure 6 tabulates the results of the mean structural differences at 8 months. [Figure 6-2] Figure 6 tabulates the results of the mean structural differences at 8 months. [Figure 6-3] Figure 6 tabulates the results of the mean structural differences at 8 months. [Figure 6-4] Figure 6 tabulates the results of the mean structural differences at 8 months. [Figure 6-5] Figure 6 tabulates the results of the mean structural differences at 8 months. [Figure 6-6] Figure 6 tabulates the results of the mean structural differences at 8 months. [Figure 6-7] Figure 6 tabulates the results of the mean structural differences at 8 months.

[0034] [Figure 7] FIG. 7 is a graphical representation of the results of FIG. [Figure 8-1] Figure 8 tabulates the results of the mode of structural differences at eight months. [Figure 8-2] Figure 8 tabulates the results of the mode of structural differences at eight months. [Figure 8-3] Figure 8 tabulates the results of the mode of structural differences at eight months. [Figure 8-4] Figure 8 tabulates the results of the mode of structural differences at eight months. [Figure 8-5] Figure 8 tabulates the results of the mode of structural differences at eight months. [Figure 8-6] Figure 8 tabulates the results of the mode of structural differences at eight months. [Figure 8-7] Figure 8 tabulates the results of the mode of structural differences at eight months.

[0035] [Figure 9] FIG. 9 is a graphical representation of the results of FIG. [Figure 10-1] Figure 10 tabulates the results of the average structural differences over the two years. [Figure 10-2] Figure 10 tabulates the results of the average structural differences over the two years. [Figure 10-3] Figure 10 tabulates the results of the average structural differences over the two years. [Figure 10-4] Figure 10 tabulates the results of the average structural differences over the two years. [Figure 10-5] Figure 10 tabulates the results of the average structural differences over the two years. [Figure 10-6] Figure 10 tabulates the results of the average structural differences over the two years. [Figure 10-7] Figure 10 tabulates the results of the average structural differences over the two years.

[0036] [Figure 11] FIG. 11 is a graphical representation of the results of FIG. [Figure 12-1] Figure 12 tabulates the results of the mode of structural differences over two years. [Figure 12-2] Figure 12 tabulates the results of the mode of structural differences over two years. [Figure 12-3] Figure 12 tabulates the results of the mode of structural differences over two years. [Figure 12-4] Figure 12 tabulates the results of the mode of structural differences over two years. [Figure 12-5] Figure 12 tabulates the results of the mode of structural differences over two years. [Figure 12-6] Figure 12 tabulates the results of the mode of structural differences over two years. [Figure 12-7] Figure 12 tabulates the results of the mode of structural differences over two years.

[0037] [Figure 13] FIG. 13 is a graphical representation of the results of FIG. [Figure 14-1] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years. [Figure 14-2] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years. [Figure 14-3] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years. [Figure 14-4] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years. [Figure 14-5] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years. [Figure 14-6] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years. [Figure 14-7] FIG. 14 is a table of results of WT mean difference in CO2 loading status in WT rats at 2 years.

[0038] [Figure 15-1] FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years. [Figure 15-2] FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years. [Figure 15-3] FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years. [Figure 15-4] FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years. [Figure 15-5] FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years. [Figure 15-6] FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years. [Figure 15-7]FIG. 15 is a table of the results of WT mode differences in CO2 loading conditions in WT rats at 2 years.

[0039] [Figure 16-1] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years. [Figure 16-2] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years. [Figure 16-3] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years. [Figure 16-4] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years. [Figure 16-5] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years. [Figure 16-6] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years. [Figure 16-7] FIG. 16 is a table of the results of the APOE mean difference in CO2 challenge conditions in APOE rats at 2 years.

[0040] [Figure 17-1] FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. [Figure 17-2] FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. [Figure 17-3] FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. [Figure 17-4] FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. [Figure 17-5] FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. [Figure 17-6]FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. [Figure 17-7] FIG. 17 is a table of the results of APOE mode differences in CO2 loading conditions in APOE rats at 2 years. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Detailed Description The technique utilizes an imaging modality called quantitative ultrashort echo time contrast enhanced (QUTE-CE) MRI (Gharagouzloo et al., 2017; Gharagouzloo et al., 2015), which overcomes the semi-quantitative nature of MRI signals. This preliminary data demonstrates that QUTE-CE MRI can provide highly accurate quantitative maps of the cerebral "vasculature" from small to large vessels, providing a solid foundation for the assessment of microvascular contributions to brain function and neurological disorders.

[0042] We utilized the imaging modality QUTE-CE MRI to study micro- and macrovascular abnormalities in the APOE-ε4 knock-in rat model. It is noteworthy that the APOE-ε4 allele is the most important genetic risk factor for AD. This study involved characterizing vascular changes in 173 brain sites. Characterization of 173 sites revealed both hyper- and hypovascularization, but microvascular changes were almost entirely hypervascularized early in life (8-month-old rats), and hypovascularized later in life (24 months).

[0043] The resolution and sensitivity are such that QUTE-CE can map physiological CBV across the entire rat brain in 500,000 small volumes (or voxels). This is distributed across 173 anatomically distinct 3D volumes and can indicate capillary density, small vessel responsiveness, and vascular reserve for network-level analysis. Importantly, QUTE-CE MRI can be immediately translated, with ongoing human clinical trials to map normal cerebral vascularity in small populations. Preliminary preclinical data in ApoE4 human knock-in in a genetically engineered rat model of AD reveals a trend from hyper- to hypo-vascularization early in development prior to cognitive decline.

[0044] QUTE-CE MRI is a method that utilizes 3D UTE pulse sequences and intravascular contrast agents (CAs) to render high contrast-to-noise ratio (CNR) vascular images with quantitative signal. (See WO 2017 / 019812, which is incorporated herein by reference.) At this ultrashort TE, contrast is inverted from the typical negative contrast obtained from superparamagnetic iron oxide-nanoparticles (SPIONs) to a purely TI-enhanced positive contrast. Quantitative measurements of micro- and macro-vessels can be mapped throughout the rat brain, and functional changes in state can also be measured (Gharagouzloo et al. 2017). Absolute cerebral blood volume (qCBV) is calculated by a simple partial volume calculation using a two-compartment model of signals from blood and tissue.

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[0045] Quantitative vascular mapping of the rat brain begins with the acquisition of pre-ferumoxytol and post-ferumoxytol scans. A 3D UTE sequence with parameters optimized for blood contrast and quantification is utilized. Field corrections for coil sensitivity (B1-) and flip angle distribution (B1+) are applied along with motion correction between pre- and post-contrast images. A voxel-wise calculation of quantitative CBV (qCBV) is performed to generate qCBV maps using a two-volume blood / tissue model with knowledge of blood intensity derived from large vessels. See Figure 1A-C for image contrast. See Figure 2 for image processing pipeline. For the rat model described herein, voxels were anatomically segmented and distributed into an atlas of 173 sites for whole brain quantitative analysis with respect to both mean vascularity and microvascular density derived from the model site characteristics. Statistically significant abnormalities are found by comparing healthy and normal vasculature of rats with genetically engineered disease models.

[0046] The procedure for creating a QUTE-CE MRI image of a subject is described in detail in WO2017 / 019182. When applied to the subject's brain, a magnetic field is applied to the brain, followed by the application of a radio frequency pulse sequence at a selected repetition time (TR), and the application of a magnetic field gradient to provide a selected reversal angle (FA) to excite protons in the region of interest. Typically, the repetition time is less than about 10 ms, and the FA ranges from about 10° to about 30°, which is around the Ernst angle of doped blood, or the maximum contrast angle between doped and undoped blood. The response signal is measured during the relaxation of the protons at a selected echo time (TE) and the T1 weighted signal acquired. The echo time is an ultrashort time to echo, set to less than about 300 μs. In this way, an image of the brain is produced. Next, a paramagnetic or superparamagnetic CA is introduced into the subject's brain by injecting the agent into the vascular cavity. The acquired signal is representative of the concentration of CA in the brain and the blood volume at that particular site in the brain.

[0047] For example, the TE can be set to less than 180 μs, 160 μs, 140 μs, 120 μs, 100 μs, 90 μs, 80 μs, 70 μs, 60 μs, 50 μs, 40 μs, 30 μs, 20 μs, or 10 μs. Also, the echo time can be set to less than the time at which the blood volume displacement in the region of interest in the brain is about one order of magnitude smaller than the voxel size. The TR can be set to a value of about 2 to 10 ms. The image of the ROI can have a contrast-to-noise ratio (CNR) of at least 4, at least 5, at least 10, at least 15, at least 20, at least 30, at least 40, at least 50, or at least 60. The CNR is determined between the ROI represented in the post-contrast image and that represented in the pre-contrast image. For example, the CNR is found by examining the ROI in the SSS and taking the difference between the two signal-to-noise ratios (SNR), where the SNR is defined as the mean of a particular ROI divided by the standard deviation of the noise in the respective image. The response signal can be measured along a trajectory in k-space where the total acquisition time is longer than TE. The magnetic field can have a strength from 0.2T to 14.0T.

[0048] It should be noted that a region of interest (ROI), such as a particular region of the brain, may contain a volume fraction occupied by blood and a volume fraction occupied by tissue. Determining the volume fraction occupied by blood involves applying a radio frequency pulse sequence at a selected TR to excite protons in the region of interest before introducing CA into the ROI, measuring the response signal during relaxation of the protons at a selected TE to obtain a signal from the ROI, and comparing the signal intensity of the ROI before and after CA introduction.

[0049] Paramagnetic formulations that provide MRI contrast can act as CAs for the QUTE-CE method. Compounds containing paramagnetic iron oxide, nanoparticles, gadolinium-based contrast agents (GBCA), such molecular chelates or nanoparticles, or manganese nanoparticles can act as CAs (contrast agents). When the CA is ferumoxytol, for example, the CA is introduced into the blood at a concentration of 0.1-15 mg / kg. The nanoparticles can be delivered by bolus intravenous or intra-arterial injection and can be repeated as needed. Paramagnetic and superparamagnetic nanoparticles can act as CAs. Paramagnetic molecular chelates and superparamagnetic nanoparticles can act as CAs. Examples of paramagnetic nanoparticles are iron oxide, gadolinium, or manganese nanoparticles. Iron oxide nanoparticles can be Fe304 (magnetite), Y-Fe203 (mahemite), α-Fe2O3 (hematite), ferumoxytol, ferumoxide, ferucarbotran, or ferumoxtran. The iron oxide nanoparticles are coated with carbohydrates and can be about 1 nm to about 999 nm, or about 2 nm to about 100 nm, or about 10 nm to about 100 nm in diameter as measured by dynamic light scattering. Nanoparticle CA can carry other coatings that allow it to circulate in the blood. Nanoparticle CA can have a variety of sizes that allow it to be excreted by the kidney or liver. Some gadolinium compounds include gadofosveset trisodium, gadotereate meglumine, gadoxetic acid disodium salt, gadobutrol, gadopentetic dimeglumine, gadobenate dimeglumine, gadodiamide, gadoversetamide, or gadoteridol, and the like.

[0050] The blood volume fraction of the ROI is determined as shown below. First, a magnetic field is applied. A radio frequency pulse sequence is applied next to a selected TR and magnetic field gradient to provide a selected flip angle and excite the protons in the region of interest. The TR is less than about 10 milliseconds and the flip angle ranges from about 10° to about 30°. The response signal is measured during the relaxation of the protons at a selected TE to obtain a T1-weighted signal from the ROI. The TE is an ultrashort time to echo. It is less than about 300 μs. The first image is generated without CA using a 3D UTE sequence. Then, a paramagnetic or superparamagnetic CA is introduced into the blood. Then, a second image of the ROI is generated. The determination of the blood volume fraction includes comparing the signal intensity of the region of interest before and after the introduction of the CA. Specifically, the determination of the blood volume fraction includes determining the difference in total signal intensity between the first image and the second image, and determining the difference in blood signal intensity between the first image and the second image, and the blood volume fraction includes the ratio of the difference in total signal intensity to the difference in blood signal intensity.

[0051] QUTE-CE MRI is quantitative, thus leading to a direct assay of CA concentration, similar to nuclear imaging, but without the radiation toxicity or other complications associated with radiopharmaceuticals. Because the acquired signal is quantitative, the technique can be used for partial blood volume measurements using two volumetric methods. To date, no technique has been reported that can potentially perform absolute measurements of cerebral blood volume (qCBV) throughout the brain. QUTE-CE MRI can be used to identify hypervascularization or hypervascularization, hypovascularization, vascular reserve, vascular responsiveness to CO2 loading, perfusion defects and standardized uptake values ​​or organ absorbed doses at the individual voxel and regional level using anatomical or functional atlases. Thus, QUTE-CE MRI provides an advantageous set of imaging biomarkers or diagnostic markers to assess function and status.

[0052] In some aspects, the CA can be ferumoxytol, an ultrasmall superparamagnetic iron oxide nanoparticle (USPION) with a dextran coating. Being above the cutoff for glomerular filtration (~6 nm), ferumoxytol is not cleared by the kidney and is instead an excellent blood pool contrast agent with a long intravascular half-life of 15 hours (Bremerich et al., 2007). Numerous clinical MRI studies with ferumoxytol have been performed in children and adults and have shown no major adverse effects (Muehe et.al., 2016). Therefore, QUTE-CE can be easily used in the clinic to study SVD.

[0053] Comparison with previous clinical imaging techniques Currently, clinical imaging of cerebral SVD is indirect and mostly represents its sequelae, such as ischemic (white matter hyperintensities (WMH) (Reijmer et al., 2016), lacunar infarcts) and hemorrhagic (cerebral microvascular blocks (CMBs)) lesions (Shi et al., 2016; Greenberg et al., 2009). Such consequences of SVD can be detected in clinical settings with conventional MRI sequences, including T2 / FLAIR (WMH, chronic infarcts), DWI (acute infarcts), and susceptibility-weighted imaging (SWI) (e.g., CMBs) (Wardlaw et al., 2013). However, these techniques are limited in specificity, accuracy, and reliability in assessing the total burden of microvascular disease states (Wey et al., 2013; Brunser et al., 2013). Moreover, current MRI techniques do not provide insight into the microarchitecture of the brain's global network of cerebral small vessels or vasculature (Guo et al., 2012), which may play an important role in understanding underlying SVD pathology and disease mechanisms in stroke patients, as well as the fact that SVD in apparently healthy aging adults may be asymptomatic, yet relentlessly progressive, and ultimately disabling. Thus, to address the growing burden of SVD-related disorders, new diagnostic methods are urgently needed to reliably quantify the overall extent of SVD.

[0054] Comparison with other known approaches to measuring CBV Other MRI methods for SPION imaging exploit long-range susceptibility-inducing effects (Cunninham et al., 2005; Stuber et al., 2007; Seppenwoolde et al., 2003), whereas QUTE-CE MRI avoids them by performing T1-enhanced measurements with a TES 1000 times shorter than standard modalities. Regular T1-weighted imaging is not quantitative and does not lead to the detailed images obtained with QUTE-CE. Dynamic susceptibility contrast (DSC), or perfusion-weighted MRI, is commonly used to measure CBV values ​​(Barbier et al., 2001), but requires accurate measurement of arterial input function (AIF) (Rempp et al., 1994; Yankeelov et al., 2009) or gadolinium-based contrast agent (GBCA) concentration versus time curves, which are typically inaccurate by 15–30% (Walker-Samuel et al., 2007; Schabel et al., 2008). All other techniques for measuring CBV, such as steady-state susceptibility contrast mapping (SSGRE), steady-state CBV (SS_CBV), and ΔR2 (Tropres et al., 2001; Christen et al., 2012), are based on T2 and T2 * The iron fMRI exploits the T2 * It differs from QUTE-CE in that it is weighted, requires a high CA dose, and is sensitive to the extravascular space (Stuber et al., 2007; Mandeville, 2012). QUTE-CE is the only MR imaging technique that produces positive contrast imaging without susceptibility-induced signal dropout. Therefore, qCBV measurements obtained from QUTE-CE MRI can be used as a quantitative diagnostic marker for ADRD. EXAMPLES

[0055] All animal studies were performed in accordance with institutional IACUC-approved protocols. QUTE-CE measurements were performed on five wild-type (WT) and six APOE-ε4 knock-in female rats aged 7 months that showed signs of mild cognitive impairment.

[0056] The data suggest that early hypervascularization may be a coping mechanism to compensate for the metabolic dysfunction of aging and dementia. method Behavioral testing Measures of cognitive behavior routinely performed at the Center for Translational Neuroimaging (CTNI) are the Barnes maze for spatial memory and the Novel Object Preference (NOP) for object memory. Both Barnes and NOP rely on the hippocampus but involve different "learning" strategies (McLay et al., 1997; Assini et al., 2009; Larkin et al., 2014; Pardo et al., 2016). Although one test is sufficient, it is preferable to perform at least two tests that employ the same function / region (e.g., memory / hippocampus). A focus on hippocampal-dependent functions is desirable due to their involvement in psychiatric disorders and similarities across species (Squire et al., 1992).

[0057] Animal testing QUTE-CE MRI Biomarkers The QUTE-CE MRI measurement pipeline is shown in Figure 2. QUTE-CE vascular biomarkers: (1) voxel-based physiological blood fraction (qCBV) is measured from 0-1, where 1 is arterial or venous. sites (2) macrovascularization measures and (3) microvascularization measures are obtained by considering the mean or mode of the regional distribution, respectively. Regional volumes of interest (VOIs) detailed by a high-resolution, 173-site rat anatomical atlas (Ekam Solutions, Boston, MA), digitally fitted to the brain using an affine transformation. (4) Considering the distance between the mean and mode, regions can be classified to account for vascular heterogeneity. (5) Dynamic functional tests, such as hypercapnic challenge with 5% CO2, can be applied to investigate the responsiveness of vascular reserve.

[0058] Data format and analytical rationale For these measurements, qCBV was calculated using pre- and post-contrast UTE images. Approximately 500,000 voxels were obtained at 150 micrometer isotropic resolution in 8 minutes for the entire rat brain. However, while excellent vascular images are produced, quantification at the voxel level still shows high error. Considering voxel-based errors and slight variations in neuroanatomy from one animal to the next, it was desirable to quantify regional vascular measurements in these small animals. To achieve this, each rat brain was fitted to an anatomical atlas with 173 regions using a manually adjusted affine transformation. In the atlas, the left and right halves of the brain were combined into a single region by default settings. Thus, the 500,000 voxels were distributed among the 173 regions, and the mean and mode were calculated for each region.

[0059] To test between-group comparisons, the mean and mode list of one group was compared with the mean or mode of another group across all 173 sites. Statistical significance was achieved by a t test for differences between the two lists (P<0.05 or P<0.01). Changes in the microvasculature, or small blood vessels, were associated with the mode. The rationale was that most of the brain volume would be expected to be filled primarily with small blood vessels, and this was a way to remove influences from larger vessels that are 100% filled with blood.

[0060] QUTE-CE MRI measurements were performed on 8-month-old and 2-year-old female wild-type (WT) and APOE4+ Sprague-Dawley (SD) rats. Experiment at 8 months of age (all female SD) Structural QUTE-CE Group 1 (n=5):WT Group 2 (n=5): APOE4+ Experiments at age 2 (all female SD) Structural QUTE-CE Group 1 (n=5): WT Group 2 (n=5): APOE4+ Dynamic CO at age 2 2 Load (all female (SD) Dynamic QUTE-CE (multiple CO2 loads) Group 1 (n=5): WT Group 2 (n=5): APOE4+

[0061] result Vascular structural and functional changes were measured longitudinally in aging female APOE4 knock-in rats using QUTE-CE MRI. The technique uses FDA-approved contrast agents, is compatible with existing clinical scanners, and has been shown to be feasible for implementation in humans for routine screening of CNS diseases.

[0062] Hypervascularization in ApoE4 rats at 8 months of age Small vessels: 44 of 173 sites were altered (P<0.05), of which 39 showed increases. See Figures 6-9. A pattern of mean vascular changes was also observed, consisting of 11 increases and 25 decreases (p<0.01).

[0063] Trend toward undervascularization at age 2 years In this model, AD progressed faster in males than females, and although females did not yet show statistically significant cognitive impairment, static QUTE-CE MRI revealed an age-dependent trend of over- to under-microvascular remodeling (Figure 5A, 5B). This male / female trend in APOE4-induced disorders has been validated in rodents (www.NCBI.nlm.nlm.nh.gov / pMC / articles / pmc4687024 / PDF / nihms740272.pdf). The trend of over-microvascularization was highly correlated with brain regions showing hyperconnectivity, as measured by echo-planar imaging (EPI). The females were found to show cognitive impairment after 2 years of age, as measured by the Barnes Maze and novel object recognition tests (p<0.05).

[0064] ApoE4 rats: hypersensitivity and historical vascular dysfunction Dynamic QUTE-CE MRI revealed a hyperresponsive recruitment of vascular reserve. (Figure 5B) In ApoE4 rats, a highly significant response to breathing in 5% CO2 gas was observed, which, unlike WT, did not recover during a 1-min rest period. These data may suggest that early hypervascularization may be a coping mechanism to compensate for metabolic dysfunction in aging and dementia.

[0065] Structural differences after 8 months The tables in Figures 6-9 list the results for structural differences, both mean (p<0.01, top) and mode (p<0.05, bottom). P-values ​​are displayed and mean qCBV along with STD are available between all animals in the two groups (see Methods, Group Comparison at 8 months of age). Site numbers are the assigned site numbers in the anatomical atlas and rows are organized so that the largest qCBV (APOE4 mean or mode - WT mean or mode) is at the top (hypervascular APOE4). On the right side of the tables below comparing modes, site names and their p-values ​​are listed in order of significance. Of the 173 sites, non-significant sites have been omitted.

[0066] Structural differences at age 2 Tables in Figures 10-13 list the results regarding structural differences, both as means (p<0.01, left) and modes (p<0.05, right). H and P values ​​are presented, and mean qCBVs for WT and APOE4 are available along with the STD. Differences between the two groups were calculated, and error propagation of the subtraction of the means was used to calculate the standard deviation of the differences. Site numbers are the assigned site numbers in the anatomical atlas, and rows are organized such that the highest decrease is at the top (undervascularized APOE4). If the same site was also statistically significant relative to the change in 8-month-old rats, the site is colored dark gray and darker gray. For overvascularization, the color on the left representing the 8-month condition is dark gray (originally red), and for undervascularization, the color is dark gray (originally blue). The colors on the right correspond to undervascularization or overvascularization for the 2-year-old condition.

[0067] On average, 66 sites were observed to be statistically significant for the 18 changes at 2 years of age that were also significant at 8 months of age. Of these sites, 13 were made undervascularized and remained undervascularized, 3 were made overvascularized and remained overvascularized, 2 were made overvascularized and progressed to undervascularized, and none progressed from undervascularized to overvascularized.

[0068] Regarding mode, it can be seen that of the 32 sites that were statistically significant for change at 2 years of age, 6 were significant at 8 months of age: 2 of these sites were made undervascularized and remained undervascularized, 2 were made overvascularized and remained overvascularized, and 2 were made overvascularized and progressed to undervascularized, but none progressed from undervascularized to overvascularized.

[0069] Dynamic CO at age 2 2 The tables in Figures 14-17 show the results of the two groups tested at 2 years of age. The following tables show the mean and mode differences in the CO2-challenging conditions. That is, M1 and its STD represent the mean of the differences each animal had per region. By following the mean of the within-animal differences rather than the absolute values, we can test for statistical significance while ignoring comparisons between animals.

[0070] All were compared to the first post-contrast scan (scan 1) from which qCBV was calculated. Scans 2-4 were performed with CO2 on (M1 is the mean difference), CO2 off (M2 is the mean difference) and finally with CO2 turned back on (M3 is the mean difference). h and p values ​​are also shown. The comparison of h1, p1 corresponds to the initial state of CO2, h2, p2 when CO2 was turned off again and h3, p3 when CO2 was turned on again.

[0071] As used herein, "consisting essentially of" can include materials or steps that do not materially affect the basic and novel characteristics of the claim. References herein to the term "comprising" can be interchanged with "consisting essentially of" or "consisting of," particularly in describing components of a composition or elements of a device. While the present technology has been described in conjunction with certain preferred embodiments, those skilled in the art, after reading the above specification, may affect various modifications, substitutions of equivalents, and other alterations to the compositions and methods defined herein.

[0072] References [Table 1-1] [Table 1-2] [Table 1-3]

Claims

1. 1. A method of operating a medical image analysis device to determine the likelihood of onset or progression of a neurophysiological condition in a subject, comprising: generating a first representative quantitative cerebral blood volume (qCBV) for one or more regions of the subject's brain using one or more first magnetic resonance imaging (MRI) images of the subject's brain; generating a second representative qCBV for one or more regions of the subject's brain using one or more second MRI images of the subject's brain generated during and / or after the subject is subjected to vascular stress; detecting one or more functional changes in the cerebral vascular space of the subject based on the first representative qCBV and the second representative qCBV; and Detecting the possible onset or progression of a neurophysiological condition in a subject based on one or more functional changes in the vascular space of the subject's brain. The method comprising:

2. 2. The method of claim 1, wherein the vascular load of the subject is a hypercapnic load of the subject.

3. The method of claim 1 , wherein the vascular load of the subject is a hypoxic load of the subject.

4. One or more second MRI images of the subject's brain are taken, showing that the subject is CO ２ 10. The method of claim 1, wherein the is produced during inhalation of enriched air.

5. One or more second MRI images of the subject's brain are taken, showing that the subject is CO ２ 10. The method of claim 1, wherein the is produced after ceasing to breathe the enriched air.

6. 2. The method of claim 1, wherein the one or more functional changes in the vascular space of the subject's brain comprise a difference between the amount of cerebral blood volume in one or more regions of the brain indicated by a first representative qCBV and the amount of cerebral blood volume in one or more regions of the brain indicated by a second representative qCBV.

7. one or more processors; and 1. A storage device that, when executed by one or more processors, causes the one or more processors to: generating a first representative quantitative cerebral blood volume (qCBV) for one or more regions of the subject's brain using one or more first magnetic resonance imaging (MRI) images of the subject's brain; generating a second representative qCBV for one or more regions of the subject's brain using one or more second MRI images of the subject's brain generated during and / or after the subject is subjected to vascular stress; detecting one or more functional changes in the cerebral vascular space of the subject based on the first representative qCBV and the second representative qCBV; and Detecting the possible onset or progression of a neurophysiological condition in a subject based on one or more functional changes in the vascular space of the subject's brain. A method comprising: the storage device encoded with instructions to cause the 2. A computer system comprising:

8. The computer system of claim 7 , wherein the vascular load of the subject is a hypercapnic load of the subject.

9. The computer system of claim 7 , wherein the vascular load of the subject is a hypoxic load of the subject.

10. One or more second MRI images of the subject's brain are taken, showing that the subject is CO ２ 8. The computer system of claim 7, wherein is generated during inhalation of enriched air.

11. One or more second MRI images of the subject's brain are taken, showing that the subject is CO ２ 8. The computer system of claim 7, wherein the is generated after ceasing to inhale the enriched air.

12. 8. The computer system of claim 7, wherein the one or more functional changes in the cerebral vascular space of the subject include a difference between the amount of cerebral blood volume in one or more regions of the brain indicated by a first representative qCBV and the amount of cerebral blood volume in one or more regions of the brain indicated by a second representative qCBV.

13. At least one non-transitory computer-readable storage medium that, when executed by the at least one processor, causes the at least one processor to: generating a first representative quantitative cerebral blood volume (qCBV) for one or more regions of the subject's brain using one or more first magnetic resonance imaging (MRI) images of the subject's brain; generating a second representative qCBV for one or more regions of the subject's brain using one or more second MRI images of the subject's brain generated during and / or after the subject is subjected to vascular stress; detecting one or more functional changes in the cerebral vascular space of the subject based on the first representative qCBV and the second representative qCBV; and Detecting the possible onset or progression of a neurophysiological condition in a subject based on one or more functional changes in the vascular space of the subject's brain. A method comprising: said storage medium having encoded thereon instructions for causing said medium to perform the steps of:

14. 14. The at least one non-transitory computer readable storage medium of claim 13, wherein the vascular load of the subject is a hypercapnic load of the subject.

15. 14. At least one non-transitory computer-readable storage medium according to claim 13, wherein the vascular load of the subject is a hypoxic load of the subject.

16. One or more second MRI images of the subject's brain are taken, showing that the subject is CO ２ 14. The at least one non-transitory computer-readable storage medium of claim 13, wherein the is generated during inhalation of enriched air.

17. One or more second MRI images of the subject's brain are taken, showing that the subject is CO ２ 14. The at least one non-transitory computer-readable storage medium of claim 13, wherein the is generated after ceasing to inhale the enriched air.

18. 14. At least one non-transitory computer-readable storage medium according to claim 13, wherein the one or more functional changes in the vascular spaces of the subject's brain comprise a difference between an amount of cerebral blood volume in one or more regions of the brain indicated by a first representative qCBV and an amount of cerebral blood volume in one or more regions of the brain indicated by a second representative qCBV.

Images