A bone density measurement system and a measurement method thereof

Abstract

This invention relates to a bone mineral density measurement system and method. The system includes a CT scanner with a quantitative computed tomography (QCT) module, an independent single-calibration phantom, and a QCT data image processing program. The devices can exchange data via network or mobile storage. The data receiving module of the QCT data image processing program receives medical digital images from the CT scanner and measures the patient's bone mineral density through the bone mineral density analysis module. This invention combines a CT scanner, QCT, and a single-calibration phantom, employing an asynchronous scanning method that separates the phantom and the patient. This results in higher measurement accuracy, greater convenience, and improved patient comfort.

Description

Technical Field

[0001] This invention relates to the field of medical image processing and application technology, specifically a bone density measurement system and its measurement method. Background Technology

[0002] Osteoporosis is a systemic bone disease characterized by a decrease in bone mass per unit volume of bone and alterations in bone tissue microstructure. It can cause increased bone fragility, decreased bone strength, and an increased risk of fractures throughout the body. The most important indicator for evaluating osteoporosis is bone mineral density (BMD). Methods for measuring BMD have evolved over several decades and currently include dual-energy X-ray absorptiometry (DXA), ultrasound, and quantitative CT. Quantitative CT is currently the most effective method for measuring volumetric BMD.

[0003] Currently, quantitative CT examination for BMD measurement uses the simultaneous scanning multi-calibration bone mineral density phantom method. The simultaneous scanning method requires the patient to raise their legs and bend their knees, so that their lower back or hips are as close to the phantom as possible without any gaps. Patients with limited lumbar spine or hip mobility or deformities in related areas may find it difficult to cooperate with the examination position. There are also certain requirements for the placement of the phantom relative to the human body. In addition, because the phantom itself has a high density, it is easy to produce artifacts in the CT images. The multi-calibration phantom needs to calibrate multiple different bone mineral densities. Therefore, compared with the single-calibration phantom, the manufacturing process of the multi-calibration phantom is more complex, the manufacturing cost is higher, and the size is larger. Summary of the Invention

[0004] One of the objectives of this invention is to address the shortcomings of existing technologies by providing a bone mineral density measurement system that combines a CT scanner, QCT degree of measurement, and single-calibration phantom to perform scanning in an asynchronous manner with the phantom and patient separated. This results in higher measurement accuracy, greater convenience, and improved patient comfort.

[0005] The technical solution of the present invention is as follows:

[0006] A bone mineral density measurement system includes a CT scanner with a quantitative computed tomography (QCT) module, a standalone single-calibration phantom, and a QCT data image processing program. The devices can exchange data via a network or mobile storage. The QCT program's data receiving module receives medical digital images (Dicom) from the CT scanner and measures the patient's bone mineral density through a bone mineral density analysis module.

[0007] As a preferred embodiment, the single calibration mold is formed by pressing a quantitative mixture of polyethylene, tricalcium phosphate, and hydroxyapatite.

[0008] As a preferred embodiment, the ratio of polyethylene, tricalcium phosphate, and hydroxyapatite in the single calibration phantom is 90:3:7.

[0009] Another objective of this invention is to provide a method for measuring bone mineral density, addressing the shortcomings of existing technologies.

[0010] The technical solution of the present invention is as follows:

[0011] A method for measuring bone mineral density, including

[0012] First, the CT values ​​of the multi-calibration phantom were measured using a CT scanner. The multi-calibration phantom contained various reference material columns. Linear regression was performed on the measured CT values ​​and their corresponding equivalent bone mineral density values ​​to obtain a linear model of CT values ​​versus bone mineral density values. The formula for this model is as follows:

[0013] BMD = a * H B +b

[0014] In the formula, BMD is the bone mineral density value, and H... B Here, CT value is given, and a and b are the calculated slope and intercept.

[0015] A single-calibration phantom is placed in the center of the CT scanning table. The single-calibration phantom corresponds to a single CT value. Quantitative computed tomography is performed on the single-calibration phantom to obtain axial images. Axial, coronal and sagittal images are obtained from the axial images. Regions of interest are selected on the images. Based on the linear model and the mean CT value and predicted bone mineral density value of the single-calibration phantom, the calibrated slope and intercept are calculated.

[0016] The patient places their body in the center of the scanning field, and the CT scanner obtains sufficient axial images. Coronal and sagittal images are obtained from the axial images, and the region of interest is manually selected. The mean CT value of the region of interest is analyzed using a quantitative computed tomography data image processing program. This mean CT value is then substituted into the linear model of the calibrated CT value and bone mineral density value to obtain the patient's bone mineral density value.

[0017] To ensure the accuracy of bone mineral density testing, the single-calibration phantom of this invention is scanned once a month and the linear model of CT values ​​and bone mineral density values ​​is calibrated.

[0018] The measurement method of this invention is mainly used to measure the cancellous bone of the vertebral body. The turnover rate of cancellous bone is much greater than that of cortical bone, which can better reflect metabolic diseases at an earlier stage and more sensitively reflect the treatment effect.

[0019] Among them, the ratio of polyethylene, tricalcium phosphate and hydroxyapatite in the single calibration phantom is 90:3:7, which has the highest matching degree with the measurement software.

[0020] As a preferred method, when scanning a single calibration phantom, the scanning range includes 1.2 cm from the top to 1.2 cm from the bottom of the phantom to eliminate the influence of impurities at the edges of the single calibration phantom.

[0021] As a preferred embodiment, when the scanning is set to a layer thickness of 2.5 mm and a pitch of 1.0, a single calibrated phantom scan can obtain 70 layers of axial images.

[0022] As a preferred method, a quantitative computed tomography (CT) image processing program is used to calculate the standard deviation T value of the patient's bone mineral density (BMD) compared with the average BMD of normal young adults of the same sex, and the standard deviation Z value of the patient's BMD compared with the BMD of normal young adults of the same sex, thereby generating BMD analysis results.

[0023] As a preferred method, during calibration, the single calibration phantom is placed longitudinally in the center of the CT scanning table to ensure that the single calibration phantom is within the scannable range of the CT scanner; the table height is adjusted using the CT collimator to center the single calibration phantom in the scanning field; quantitative computed tomography is performed on the single calibration phantom, and multiplanar reconstruction is performed on the obtained axial images; all axial images are stacked sequentially and then reconstructed in coronal and sagittal planes; regions of interest are selected on the obtained axial, coronal, and sagittal images.

[0024] As another preferred method, when measuring the patient's bone density, the patient's body is placed in the center of the scanning field, and a sufficient number of axial images are obtained by the CT scanner; the obtained axial images are reconstructed in multiple planes to obtain their corresponding coronal and sagittal images, and the region of interest is manually selected.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention uses a single calibration phantom, which is simpler to manufacture, has lower manufacturing costs, and is smaller in size compared to multi-calibration phantoms. It can achieve large-scale production, significantly reduce costs, and is also more convenient to transport and store.

[0027] Furthermore, the asynchronous single-calibration phantom bone density measurement method of the present invention uses an asynchronous scanning method that separates the phantom and the patient. Since the patient's entire scanning process does not require the phantom's participation, the patient does not need to cooperate with a position involving the phantom, and there will be no artifacts in the patient's CT images due to the phantom.

[0028] Furthermore, this invention has a quality control calibration process, which ensures the accuracy of the asynchronous single-calibration phantom bone mineral density measurement results; and the measurement results have been verified by experiments, showing that the asynchronous single-calibration phantom bone mineral density measurement results of this invention are not significantly different from the synchronous multi-calibration phantom bone mineral density measurement results, thus making it suitable for large-scale application in the field of bone mineral density measurement.

[0029] In summary, this invention has the advantages of low cost, convenient measurement, and high measurement accuracy, and is particularly suitable for the field of bone density measurement equipment technology. Attached Figure Description

[0030] The invention will be further described below with reference to the accompanying drawings:

[0031] Figure 1 This is a schematic diagram of a single-calibrated phantom CT scan.

[0032] Figure 2 This is a single-calibration phantom image from bone mineral density analysis software. Detailed implementation method:

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] Example 1

[0036] like Figures 1 to 2 As shown, a bone mineral density measurement system includes a CT scanner with a quantitative computed tomography (QCT) module, an independent single-calibration phantom 101, and a QCT data image processing program. The devices can exchange data via a network or mobile storage. The QCT program's data receiving module receives medical digital images (Dicom) from the CT scanner and measures the patient's bone mineral density through a bone mineral density analysis module.

[0037] The single calibration phantom 101 is formed by quantitatively mixing and pressing polyethylene, tricalcium phosphate and hydroxyapatite.

[0038] In the single-calibration phantom 101, the ratio of polyethylene, tricalcium phosphate, and hydroxyapatite is 90:3:7. This ratio is the parameter value with the highest matching degree to the bone mineral density measurement method obtained from multiple experiments.

[0039] Example 2

[0040] A method for measuring bone mineral density, including

[0041] First, the CT values ​​of the multi-calibration phantom were measured using a CT scanner. The multi-calibration phantom contained various reference material columns. Linear regression was performed on the measured CT values ​​and their corresponding equivalent bone mineral density values ​​to obtain a linear model of CT values ​​versus bone mineral density values. The formula for this model is as follows:

[0042] BMD = a * H B +b

[0043] In the formula, BMD is the bone mineral density value, and H... B Here, CT value is given, and a and b are the calculated slope and intercept.

[0044] The single-calibration phantom 101 is placed in the center of the CT scanning table. The single-calibration phantom corresponds to a single CT value. Quantitative computed tomography scan is performed on the single-calibration phantom to obtain axial images. Axial, coronal and sagittal images are obtained using the axial images. Regions of interest are selected on the images. Based on the linear model and the mean CT value and predicted bone mineral density value of the single-calibration phantom, the calibrated slope and intercept are calculated.

[0045] When scanning the single calibration phantom 101, the scanning range includes 1 cm from the top to 1 cm from the bottom of the phantom. This range setting can eliminate the influence of impurities at the edge of the single calibration phantom, so as to make the scanning results more accurate.

[0046] When the scanning is set to a layer thickness of 2.5 mm and a pitch of 1.0, a single calibration phantom scan obtains 70 layers of axial images. Of course, other scanning layer thickness and pitch values ​​can also be set to obtain axial images of different layers. This setting is only a preferred option in this embodiment.

[0047] The standard deviation T-value of the patient's bone mineral density value compared with the average bone mineral density value of normal young adults of the same sex and the standard deviation Z-value of the patient's bone mineral density value compared with the average bone mineral density value of normal young adults of the same sex were calculated using a quantitative computed tomography data image processing program, and the bone mineral density analysis results were generated.

[0048] During calibration, the single calibration phantom is placed longitudinally in the center of the CT scanning table to ensure that it is within the scanning range of the CT scanner. The table height is adjusted using the CT collimator to center the single calibration phantom in the scanning field. Quantitative computed tomography is performed on the single calibration phantom, and multiplanar reconstruction is performed on the obtained axial images. All axial images are stacked sequentially, and coronal and sagittal images are reconstructed. Regions of interest are selected on the obtained axial, coronal, and sagittal images.

[0049] The procedure for examining a patient's lumbar spine is as follows:

[0050] 1. The patient places their body in the center of the scanning field so that the CT scanner can obtain sufficient axial images.

[0051] 2. Perform multiplanar reconstruction on the obtained axial images to obtain their corresponding coronal and sagittal images, and manually select the region of interest in one of the first, second, third, and fourth lumbar vertebrae.

[0052] 3. The mean CT value of the region of interest is obtained by analyzing the data image processing program of quantitative computed tomography. Substituting this mean value into the linear model of calibrated CT values ​​and bone mineral density values, the bone mineral density value of the patient's lumbar spine can be obtained.

[0053] 4. Calculate the standard deviation T value between the patient's bone mineral density value and the average bone mineral density value of normal young adults of the same sex in the program, and calculate the standard deviation Z value between the patient's bone mineral density value and the average bone mineral density value of normal young adults of the same sex in the program, and generate the lumbar spine bone mineral density analysis results.

[0054] Example 3

[0055] Components that are the same as or corresponding to those in Embodiment 2 are referred to using the same reference numerals as those in Embodiment 2. For simplicity, only the differences from Embodiment 2 are described below. The difference between Embodiment 3 and Embodiment 2 is as follows:

[0056] The procedure for examining a patient's hip is as follows:

[0057] 1. The patient rotates their toes inward and places their body in the center of the scanning field so that the CT scanner can obtain sufficient axial images.

[0058] 2. Perform multiplanar reconstruction on the obtained axial images to obtain their corresponding coronal and sagittal images, and select the region of interest in the hip.

[0059] 3. The mean CT value of the region of interest is obtained by analyzing the data image of quantitative computed tomography (CT) using a quantitative computed tomography (CT) image processing program. This mean CT value is then substituted into the linear model of the calibrated CT value and bone mineral density value to obtain the patient's hip bone mineral density value.

[0060] 4. Calculate the standard deviation T value between the patient's bone mineral density value and the average bone mineral density value of normal young adults of the same sex in the program, and calculate the standard deviation Z value between the patient's bone mineral density value and the average bone mineral density value of normal young adults of the same sex in the program, and generate the hip bone mineral density analysis results.

[0061] In the description of this invention, it should be understood that the terms "front and back", "left and right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0062] Of course, those skilled in the art should understand that the term "a" should be understood as "at least one" or "one or more". That is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. The term "a" should not be understood as a limitation on the quantity.

[0063] The above description, in conjunction with the accompanying drawings, represents only preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention. These modifications and improvements should also be considered within the scope of protection of the present invention and will not affect the effectiveness and practicality of the present invention.

Claims

1. A method of performing a bone density measurement with a bone density measurement system, characterized by, The bone density measurement system includes a CT scanner with a quantitative computed tomography module, a separate single calibration phantom, and a computer storage medium storing a quantitative computed tomography data image processing program. The single calibration mold is formed by pressing a quantitative mixture of polyethylene, tricalcium phosphate and hydroxyapatite. The ratio of polyethylene, tricalcium phosphate and hydroxyapatite in the single calibration phantom is 90:3:

7. First, the CT values ​​of the multi-calibration phantom were measured using a CT scanner. The multi-calibration phantom contained various reference material columns. Linear regression was performed on the measured CT values ​​and their corresponding equivalent bone mineral density values ​​to obtain a linear model of CT values ​​versus bone mineral density values. The formula for this model is as follows: BMD = a*H B + b In the equation, BMD is the bone density value, H B is the CT value, and a and b are the calculated slope and intercept; A single-calibration phantom is placed in the center of the CT scanning table. Each phantom corresponds to a single CT value. Quantitative computed tomography (CT) scans are performed on the phantom to obtain axial images. Coronal and sagittal images are then obtained from the axial images. Regions of interest are selected on the axial, coronal, and sagittal images. Based on the linear model and the mean CT value and predicted bone mineral density value of the phantom, the calibrated slope and intercept are calculated to obtain a linear model of the calibrated CT value and bone mineral density value. The patient places their body in the center of the scanning field, and the CT scanner obtains sufficient axial images. The corresponding coronal and sagittal images are obtained from the axial images, and the region of interest is manually selected. The mean CT value of the region of interest is analyzed and obtained using a quantitative computed tomography data image processing program. This mean CT value is then substituted into the linear model of the calibrated CT value and bone mineral density value to obtain the patient's bone mineral density value. When scanning a single calibration phantom, the scanning range includes 1.2 cm from the top to 1.2 cm from the bottom of the phantom to eliminate the influence of impurities at the edges of the single calibration phantom.

2. The method for measuring bone mineral density according to claim 1, characterized in that, When the scanning is set to a layer thickness of 2.5 mm and a pitch of 1.0, a single calibration phantom scan obtains 70 layers of axial images.

3. The method for measuring bone mineral density according to claim 1, characterized in that, The standard deviation T-value of the patient's bone mineral density (BMD) compared with the average BMD of normal young adults of the same sex, and the standard deviation Z-value of the patient's BMD compared with the average BMD of normal young adults of the same sex, were calculated using a quantitative computed tomography (CT) image processing program to generate BMD analysis results.

4. The method for measuring bone mineral density according to claim 1, characterized in that, During calibration, the single calibration phantom is placed longitudinally in the center of the CT scanning table to ensure that it is within the scanning range of the CT scanner. The table height is adjusted using the CT collimator to center the single calibration phantom in the scanning field. Quantitative computed tomography is performed on the single calibration phantom, and multiplanar reconstruction is performed on the obtained axial images. All axial images are stacked sequentially and then reconstructed into coronal and sagittal images. Regions of interest are selected on the obtained axial, coronal, and sagittal images.

5. The method for measuring bone mineral density according to claim 1, characterized in that, When measuring a patient's bone mineral density, the patient's body is placed in the center of the scanning field, and a sufficient number of axial images are obtained by the CT scanner. Multiplanar reconstruction is performed on the obtained axial images to obtain their corresponding coronal and sagittal images, and then the region of interest is manually selected.

Images