Method and system for providing a body composition assessment standard that is invariant to weight change - Patent Application 20070122997

Abstract

The present invention relates to a system and method for providing a body composition assessment baseline that is invariant to weight change for a subject individual. First and second values ​​of a body parameter of the subject individual are obtained for a first and a second time point, respectively. First and second values ​​of a subject characteristic parameter comprising a body weight of the subject individual are obtained for the first and the second time point. Two groups of individuals are selected from a database based on a comparison with the subject characteristic parameters. A mean or median value is determined. A baseline for assessment is provided by the determined first body parameter change based on the mean or median value combined with the first and second values ​​of the body parameter of the subject individual.

Description

[Technical Field]

[0001] The present disclosure relates to methods and systems for providing a body composition assessment standard for an individual subject that is invariant to weight change. [Background technology]

[0002] In many therapeutic situations, weight loss or weight gain can be studied to evaluate the treatment. However, simply assessing weight loss or gain does not provide a true view of an individual's development. Weight loss or weight gain can be both positive and negative, and this is provided by the distinction between different weight loss treatments, such as maintaining muscle health or shifting fat distribution. Therefore, criteria for such evaluations are needed that take into account additional aspects of an individual's body composition. Summary of the Invention

[0003] It is an object of the present invention to provide an improved solution that alleviates the above-mentioned drawbacks associated with current methods. It is a further object of the present invention to provide a method and system for providing a body composition assessment standard for an individual subject that is invariant to weight changes.

[0004] The invention is defined by the accompanying independent claims, and embodiments are set out in the accompanying dependent claims, the following description and the drawings.

[0005] According to a first aspect of the present invention, there is provided a method for providing a body composition assessment standard for an individual subject that is invariant to weight change. The method is performed by a processing unit and includes the steps of obtaining a first value of a body parameter for the subject individual at a first time point, wherein the body parameter is a fat or muscle related parameter, and obtaining a second value of the body parameter for the subject individual at a second time point different from the first time point, obtaining a first value of a first subject characteristic parameter for the subject individual at the first time point, wherein the first subject characteristic parameter comprises weight optionally in combination with one or more of height, age, sex, ethnicity, BMI or other body measurements, and obtaining a second value of a second subject characteristic parameter for the subject individual at the second time point, wherein the second subject characteristic parameter comprises weight optionally in combination with one or more of height, age, sex, ethnicity and BMI, and selecting a first group of individuals from a first database, wherein the first database comprises, for each of a plurality of individuals, a value of the body parameter and the first subject characteristic parameter, and wherein selecting the first group of individuals from the first database includes: selecting a second group of individuals from a second database based on a first subject characteristic parameter value for the selected individuals being similar to a first value of the first subject characteristic parameter for the subject individual, wherein the second database comprises a value of a physical parameter and a second subject characteristic parameter for each of a plurality of individuals, and selecting the second group of individuals from the second database based on a second subject characteristic parameter value for the selected individuals being similar to a second value of the second subject characteristic parameter for the subject individual; determining a first mean or median of a distribution of physical parameter values ​​for the individuals in the first group of individuals; determining a second mean or median of a distribution of physical parameter values ​​for the individuals in the second group of individuals; determining a first standard deviation based on a relationship between the first mean or median and the first value of the physical parameter for the subject individual; and determining a standard deviation based on a relationship between the second mean or median and the second value of the physical parameter for the subject individual.determining a second deviation value; and determining a first body parameter change by comparing the first deviation value with the second deviation value.

[0006] The determined first body parameter change can therefore provide a basis for an effective assessment of the subject's body composition that is invariant to weight change. Because the body parameter values ​​at two different time points use different groups of individuals from the database as references, weight change for the subject itself may not affect the assessment. Instead, the two body parameter values ​​can be assessed using a reference group that is relevant for the value of the body parameter at a particular time. The body parameter can be correlated with the subject's weight. The body parameter can indicate how much weight the subject should gain or lose. Comparing the body parameter value at the second time point to a parameter-based value comprising the weight of a reference group that is relevant to the subject's weight at that time can therefore make the determination of the body parameter change more relevant to the assessment.

[0007] Body composition assessment that is invariant to weight change may mean that the assessment is based on a determination that takes into account weight change between different time points. Between two time points, the first and second values ​​of the body parameter may have changed (increased or decreased) by an absolute value. This absolute value may not provide a completely true picture for the assessment of the subject's individual body composition. By using the method of the present invention, in which a reference group is used that makes body parameter change invariant to weight, a truer picture of the change in body parameter value between two time points is provided. Body composition assessment can then be performed on an improved basis.

[0008] A body parameter can be a measurable parameter of an individual subject's body that defines a parameter of the body's composition. The body parameter can be fat- or muscle-related. Fat- or muscle-related can refer to a parameter of one or more fat or muscle compartments in the body, e.g., the volume or weight of such compartments, or a parameter based on one or more fat or muscle compartments, e.g., a parameter based on the volume or weight of such compartments.

[0009] The first time point is different from the second time point, and the second time point can be a later time point than the first time point.

[0010] The first subject characteristic parameter is a parameter comprising the subject individual's weight. Optionally, the first subject characteristic parameter comprises a combination between the subject individual's weight and one or more of the subject individual's height, age, sex, ethnicity, BMI, or another body measurement. The other body measurement may be another measurable entity of the subject individual. The same applies to the second subject characteristic parameter.

[0011] The first database may include data on a large number of individuals. For each individual in the first database, values ​​of at least a first subject characteristic parameter and a physical parameter are stored. Individuals for the first group may be selected based on whether the first subject characteristic parameter for each selected individual is similar, e.g., within a predetermined interval, to a first value of the first characteristic parameter of the subject individual. When the first characteristic parameter includes a combination of weight and, e.g., age, the selection may be performed in two steps, with the first selection being based on weight. Among the individuals selected in the first selection, individuals for the first group may be selected based on age. When the first subject characteristic parameter is a combination of more than two entities (e.g., weight, age, and BMI), the selection of the first group may similarly be performed in three or more steps. For each entity (weight, height, age, sex, ethnicity, BMI, other physical measurement) on which the selection of the first group is based, a predetermined interval may be set, and the entity value must be within this predetermined interval from the value of the subject individual to be determined to be similar to the value of the subject individual. In order to determine that the selected individuals have similar, for example, weight, to the subject individual, the interval for the entities used for selection can, in one embodiment, be adapted to the number of individuals in the database having subject characteristic parameters within the interval. The number of individuals to be selected for the first group can be predetermined. The same applies to the second subject characteristic parameters and the selection of the second group of individuals from the second database. The number of individuals selected for the two groups can be the same.

[0012] For each individual in the selected first group of individuals, the first database comprises a value of the physical parameter. If the first group comprises N selected individuals, N values ​​of the physical parameter may be determined. A first mean or median may be based on the N values ​​of the physical parameter. Furthermore, if a first standard deviation of the distribution of physical parameter values ​​is determined, the first standard deviation may be based on the N values ​​of the physical parameter for the N individuals in the first group. The same applies to a second mean or median and an optional second standard deviation. If the second group comprises M individuals, the second mean or median and the second standard deviation may be based on the M values ​​of the physical parameter in the second database for the individuals in the second group.

[0013] An absolute deviation value may be determined based on the relationship between the first mean or median value and the first value of the physical parameter. Alternatively, the relationship between the first mean or median value and the first value of the physical parameter may be used to determine a normalized deviation. The same may apply to the second deviation value.

[0014] The first and second deviation values ​​may, in one embodiment, be determined as the difference between the respective mean or median values ​​and the values ​​of the body parameters.

[0015] The processing unit may comprise one or more computer units, data processing units, and / or general-purpose processors configured to perform the steps of the method according to any of the embodiments herein. The processing unit may comprise a computer program or software configured to perform the steps of the method when executed. The processing unit may comprise or be communicatively connected to a computer-readable storage medium comprising the computer program or software.

[0016] In one embodiment, the method may further comprise determining a first standard deviation of the distribution of body parameter values ​​for individuals in the first group of individuals and a second standard deviation of the distribution of body parameter values ​​for individuals in the second group of individuals. The first deviation value may be a first z-score, and determining the first z-score may further comprise dividing a difference between a first mean or median and the first value of the body parameter by the first standard deviation. Further, the second deviation value may be a second z-score, and determining the second z-score may comprise dividing a difference between a second mean or median and the second value of the body parameter by the second standard deviation. The first body parameter change may be determined by the difference between the first z-score and the second z-score.

[0017] The first z-score can be determined based on a first value, a first mean or median, and a first standard deviation of the subject's physical parameter. The difference between the subject's first value and the first mean or median of the subject's physical parameter can be determined by the number of standard deviations. The difference can provide the first z-score. The same applies to a second z-score determined based on a second value, a second mean or median, and a second standard deviation of the subject's physical parameter. Thus, the deviation can be normalized by determining a z-score.

[0018] In one embodiment, the method may further comprise the steps of determining a predicted change value by comparing a first mean or median value with a second mean or median value, and determining a body parameter change value by comparing a first value of the body parameter with a second value of the body parameter, wherein the step of determining the first body parameter change may be performed by comparing the predicted change value with the body parameter change value.

[0019] The predicted change value may provide the difference between a first mean or median value and a second mean or median value. The body parameter change value may provide the difference between a first value and a second value of the body parameter for the individual subject. Based on these two differences being compared, the body parameter change may be determined. Thus, the deviation between the predicted body parameter change from the mean or median value for the reference group and the actual body parameter change for the individual subject may be determined. This may provide a deviation in absolute value from the predicted change value based on the reference group. As an example, it may be determined that the individual subject lost 2 liters more visceral adipose tissue than the reference group. This may provide a basis for evaluation of the individual subject's body parameter.

[0020] In one embodiment, the method may further comprise combining the first body parameter change determined based on the z-score with the determined body parameter deviation value, which may provide a more complete basis for assessment, including deviations in absolute values.

[0021] In one embodiment, the body parameter may be a parameter from the group of visceral adipose tissue mass, abdominal subcutaneous adipose tissue mass, liver fat mass, muscle volume, muscle fatty infiltration, organ volume and organ fatty infiltration.

[0022] In one embodiment, the first and second time points can be separated in time by at least one week, at least one month, at least six months, about 10-14 months, or at least 12 months. Thus, the second time point can be at least one week, at least one month, at least six months, about 10-14 months, or at least 12 months after the first time point. The first and second time points can be time points at which the first and second values ​​of a physical parameter for the individual subject and the values ​​of the first and second subject-characteristic parameters for the individual subject are associated. That is, the first value of a physical parameter can be the value of the physical parameter for the individual subject at the first time point. Correspondingly, the second value can be the value of the physical parameter for the individual subject at the second time point. The same applies to the values ​​of the first and second subject-characteristic parameters for the individual subject.

[0023] In one embodiment, the first subject characteristic parameter and the second subject characteristic parameter may be the same subject characteristic parameter, such that both the first and second characteristic parameters may be weight in optional combination with the same one or more other body measurements, such as height, age, sex, ethnicity, BMI, etc.

[0024] In one embodiment, the first subject characteristic parameter and / or the second subject characteristic parameter may be a body weight for the individual subject in combination with the gender of the individual subject.

[0025] In one embodiment, the first subject characteristic parameter and / or the second subject characteristic parameter may be a body weight for the individual subject in combination with an age for the individual subject.

[0026] In one embodiment, the first subject characteristic parameter and / or the second subject characteristic parameter may be a weight for the individual subject in combination with a height for the individual subject.

[0027] In one embodiment, the first subject characteristic parameter and / or the second subject characteristic parameter may be a body weight for the individual subject in combination with the ethnicity of the individual subject.

[0028] In one embodiment, the first subject characteristic parameter and / or the second subject characteristic parameter may be a weight for the individual subject in combination with the individual subject's BMI.

[0029] In one embodiment, the selection of the first and / or second groups of individuals may be performed by selecting individuals from the first and / or second databases having first and / or second subject characteristic parameter values ​​within a predetermined interval of the first and / or second values ​​of the first and / or second subject characteristic parameters of the subject individuals. The predetermined interval may be based on the number of individuals desired for the first and / or second groups, the absolute values ​​of the first and / or second values ​​of the subject characteristic parameters, or the number of individuals in the first and / or second databases. The predetermined interval may be changed in an iterative process if the desired number of individuals in the first and / or second groups of individuals is not reached in a first iteration of selecting individuals.

[0030] In one embodiment, the first database and the second database may be the same database comprising values ​​of the physical parameter, the first subject-characteristic parameter, and the second subject-characteristic parameter for each of a plurality of individuals therein.

[0031] In one embodiment, determining the first body parameter change may comprise determining the difference between the first z-score and the second z-score, or the difference between the predicted change value and the body parameter change value. The difference between the z-score or predicted change value and the body parameter change value may provide an output as a number that may form a basis for body composition assessment invariant to weight change.

[0032] In one embodiment, the first and second values ​​of the body parameters of the subject individual may be obtained based on MRI. In one embodiment, obtaining the values ​​of the body parameters and one or more of the first and / or second subject-characteristic parameters may comprise receiving said values ​​from a measurement unit and / or a storage unit. In another embodiment, said steps may comprise measuring and / or determining said values. Such measuring and / or determining may be based at least in part on MRI.

[0033] In one embodiment, the first group and / or second group of individuals may comprise at least 10, at least 50, or at least 100 individuals selected from the first database and / or the second database.

[0034] In one embodiment, the body parameter may be a first body parameter, and the method includes obtaining a first value of a second body parameter for the subject individual at a first time point, wherein the second body parameter is a fat or muscle related parameter different from the first body parameter, and obtaining a second value of the second body parameter for the subject individual at a second time point, the first database further comprising a value of the second body parameter for each of a plurality of individuals therein, the second database further comprising a value of the second body parameter for each of a plurality of individuals therein, and determining a third mean or median and a third standard deviation of the distribution of the second body parameter for individuals in the first group of individuals. determining a fourth mean or median and a fourth standard deviation of the distribution of the second body parameter for individuals in the second group of individuals; determining a third z-score by dividing the difference between the third mean or median and the first value of the second body parameter by the third standard deviation; determining a fourth z-score by dividing the difference between the fourth mean or median and the second value of the second body parameter by the fourth standard deviation; determining a second body parameter change by determining the difference between the third z-score and the fourth z-score; and combining the first body parameter change and the second body parameter change.

[0035] By determining a second body parameter change and combining the second body parameter change with the first body parameter change, a more complex basis for body composition assessment can be provided that cannot be achieved using a single body parameter change criterion. Two different body parameters can be assessed and compared using the methods of the present invention with a reference group. Connections between the two body parameters can be determined and found in the determined criterion, thereby providing a basis for a more complex assessment.

[0036] In an alternative embodiment, the first and second body parameter changes may be determined based on standard deviations instead of z-scores. Instead of determining four z-scores, four standard deviations may be determined, similar to how the first and second standard deviations are determined in the above-described embodiment. The standard deviations may be based on the four mean or median values ​​and the four values ​​of the first and second body parameters. The relationship between the mean or median values ​​and the respective values ​​of the body parameters is thus provided in absolute values ​​and may be used as a measure of the first and second body parameter changes. In such an embodiment, the determination of a standard deviation may be omitted.

[0037] In one embodiment, the second physical parameter may be a parameter from the group of visceral adipose tissue mass, abdominal subcutaneous adipose tissue mass, liver fat mass, muscle volume, muscle fatty infiltration, organ volume, and organ fatty infiltration, and the second physical parameter is a parameter from the above group that is different from the first physical parameter.

[0038] According to a second aspect of the present invention, there is provided a system for providing a basis for assessment of weight change in a body parameter distribution for a subject individual, the system comprising: obtaining a first value of a body parameter for the subject individual at a first time point, wherein the body parameter is a fat or muscle related parameter; obtaining a second value of the body parameter for the subject individual at a second time point different from the first time point; obtaining a first value of a first subject characteristic parameter for the subject individual at the first time point, wherein the first subject characteristic parameter optionally comprises weight in combination with one or more of height, age, sex, ethnicity, BMI or other body measurements; obtaining a second value of a second subject characteristic parameter for the subject individual at the second time point, wherein the second subject characteristic parameter optionally comprises weight in combination with one or more of height, age, sex, ethnicity and BMI; selecting a first group of individuals from a first database, wherein the first database comprises, for each of a plurality of individuals, a value of the body parameter and the first subject characteristic parameter; selecting a second group of individuals from a second database, wherein the selection of the first group of individuals from the second database is based on a first subject characteristic parameter value for the selected individuals being similar to a first value of the first subject characteristic parameter for the subject individual, the second database comprising a physical parameter and a value of a second subject characteristic parameter for each of a plurality of individuals, the selection of the second group of individuals from the second database being based on a second subject characteristic parameter value for the selected individuals being similar to a second value of the second subject characteristic parameter for the subject individual, determining a first mean or median of a distribution of physical parameter values ​​for the individuals in the first group of individuals, determining a second mean or median of a distribution of physical parameter values ​​for the individuals in the second group of individuals, determining a first deviation value based on a relationship between the first mean or median and the first value of the physical parameter for the subject individual, and determining a second deviation value based on a relationship between the second mean or median and the second value of the physical parameter for the subject individual;and determining a first body parameter change by comparing the first deviation value with the second deviation value.

[0039] The system may receive a first value of the body parameter measured or determined by another entity, such as by an acquisition unit, or the system may comprise an acquisition unit configured to measure or determine the first value. The measurement or determination may be based on an MRI scan of the subject individual. A first value of a first subject-characteristic parameter of the subject individual is acquired. As with the first value of the body parameter, the system may receive the first value of the subject-characteristic parameter from an acquisition unit or may comprise an acquisition unit. The processing unit is configured to acquire the body parameter and the first value of the first subject-characteristic parameter. The acquisition may be directly from the acquisition unit or may be from a storage unit that previously received the first value. The acquisition unit and / or the storage unit may optionally be included in the system.

[0040] The processing unit may comprise one or more computer units, data processing units, general-purpose processors, or the like, according to any of the embodiments herein. The processing unit may comprise a computer program or software configured to function according to any of the embodiments herein when executed. The processing unit may comprise or be communicatively connected to a computer-readable storage medium comprising the computer program or software.

[0041] In one embodiment, the processing unit may be configured to determine a first standard deviation of the distribution of body parameter values ​​for individuals in a first group of individuals and a second standard deviation of the distribution of body parameter values ​​for individuals in a second group of individuals, the first deviation value being a first z-score, the processing unit may be configured to determine the first z-score by dividing a difference between a first mean or median and the first value of the body parameter by the first standard deviation, the second deviation value being a second z-score, the processing unit may be configured to determine the second z-score by dividing a difference between a second mean or median and the second value of the body parameter by the second standard deviation, and a first body parameter change may be determined by the difference between the first z-score and the second z-score.

[0042] What has been further explained above for the method embodiment according to the first aspect of the invention is equally applicable to the system embodiment of the second aspect of the invention, and the processing unit may be configured to perform such steps in accordance with the above-mentioned embodiments.

[0043] The invention will be explained in more detail below with reference to the enclosed drawings. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 shows a flowchart of a method according to one embodiment of the present invention. [Figure 2a] FIG. 2a shows a block scheme of the method implemented by a system according to one embodiment of the present invention. [Figure 2b] FIG. 2b shows a block scheme of the method implemented by a system according to one embodiment of the present invention. [Figure 3] FIG. 3 shows a block scheme of a method implemented by a system according to an embodiment of the present invention. [Figure 4] FIG. 4 shows a block scheme of a method implemented by a system according to an embodiment of the present invention. [Figure 5] FIG. 5 shows a block scheme of a system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements.

[0046] 1 illustrates a method 100 for providing a weight-change invariant body composition assessment basis for a subject individual 1. The method 100 comprises obtaining two values ​​of a first body parameter of the subject individual 1, the two values ​​being obtained for the subject individual 1 at separate time points T1 and T2. In a first step of the method 100, a first value 10 of the first body parameter BP1 of the subject individual 1 at the first time point T1 is obtained 101. The body parameter BP1 is a fat- or muscle-related parameter, such as visceral adipose tissue mass, abdominal subcutaneous adipose tissue mass, liver fat mass, muscle volume, muscle fat infiltration, organ volume, and organ fat infiltration.

[0047] In a further step, a second value 20 of the first body parameter BP1 of the subject individual 1 at a second time point T2 is obtained 102. The second time point T2 is different from the first time point T1. The two time points are preferably separated by at least 1 month, at least 6 months, 10-14 months, or at least 12 months.

[0048] In addition to the value of the first physical parameter BP1, values ​​of first and second subject characteristic parameters SCP1, SCP2 are obtained for subject individual 1. A first value 11 of the first subject characteristic parameter SCP1 for subject individual 1 at a first time point T1 is obtained 103, and a second value 21 of the second subject characteristic parameter SCP2 for subject individual 1 at a second time point T2 is obtained 104. The first subject characteristic parameter SCP1 comprises weight, optionally in combination with one or more of height, age, sex, ethnicity, BMI, or other body measurements. The second subject characteristic parameter SCP2 comprises weight, optionally in combination with one or more of height, age, sex, ethnicity, and BMI. In some embodiments, the first and second subject characteristic parameters SCP1, SCP2 are the same, e.g., weight in combination with BMI, age, and / or sex.

[0049] The method 100 further comprises a step 105 of selecting a first group 12 of individuals from a first database DB1. The first database DB1 comprises values ​​of a first body parameter BP1 and a first subject characteristic parameter SCP1 for each of a plurality of individuals, and the selection of the first group 12 of individuals from the first database DB1 is based on the first subject characteristic parameter value for the selected individuals being similar to a first value 12 of the first subject characteristic parameter for the subject individual 1.

[0050] The method 100 further comprises a step 106 of selecting individuals of the second group 22 from a second database DB2. The second database DB2 comprises values ​​of the physical parameter BP1 and the second subject-characteristic parameter SCP2 for each of a plurality of individuals, and the selection of individuals of the second group 22 from the second database DB2 is based on the similarity of the value of the second subject-characteristic parameter of the selected individual to the second value of the second subject-characteristic parameter for the subject individual 1. The first and second databases DB1, DB2 are, in some embodiments, the same database. In this case, such common database comprises values ​​of the first physical parameter BP1, the first subject-characteristic parameter SCP1, and the second subject-characteristic parameter SCP2 for each subject individual therein. Different selections of individuals may be made in two selections 105, 106 for individuals of the two groups 12, 22. The two selections 105, 106 each have a different selection input: a first value of a first subject characteristic parameter SCP1 for subject individual 1 and a second value of a second subject characteristic parameter SCP2 for subject individual 1. When selecting individuals for the first and / or second groups 12, 22, the selection is, in some embodiments, made by selecting individuals having first and / or second subject characteristic parameter values ​​within a predetermined interval of the first and / or second values ​​of the first and / or second subject characteristic parameters of the subject individuals. The selection may be made iteratively until a predetermined number of individuals for each group is reached. Such a predetermined number may be at least 10, at least 50, or at least 100 individuals for each group.

[0051] For selected individuals in the individuals of the two groups 12, 22, a value of a first body parameter BP1 for each individual is provided. The method 100 comprises a step 107 of determining a first mean or median M1 of the distribution of first body parameter values ​​for individuals in the individuals of the first group 12. Further, there is a step 108 of determining a second mean or median M2 of the distribution of first body parameter values ​​for individuals in the individuals of the second group 22.

[0052] The determined first and second mean or median values ​​M1, M2 are then used to determine 111 a first body parameter change 30, 30' by comparing the two mean or median values ​​M1, M2 and combining them with a first value 10 and a second value 20 of the subject's individual first body parameter BP1.

[0053] In one embodiment, step 107 further comprises determining a first standard deviation SD1 of the distribution of body parameter values ​​for individuals in the first group of individuals, and step 108 further comprises determining a second standard deviation SD2 of the distribution of body parameter values ​​for individuals in the second group of individuals. In this embodiment, method 100 further comprises steps 109, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970 Thus, the first body parameter change 30, 30' provides a basis for body composition assessment that is invariant to weight changes.

[0054] FIG. 2a further illustrates a method 100 as performed by a system 2, which will be further described in relation to FIG. 5. A first value 10 of a first body parameter BP1 of an individual 1 is acquired. The first value 10 may be received, measured, or determined by another entity, such as by an acquisition unit, or the system 2 may comprise an acquisition unit configured to measure or determine the first value 10. The measurement or determination may be based on an MRI scan of the subject individual 1. A first value 11 of a first subject-characteristic parameter SCP1 of the subject individual 1 is acquired. Similar to the first value 10, the system 2 may receive the first value 11 from an acquisition unit or may comprise an acquisition unit. The processing unit is configured to acquire the first value 10, 11. The acquisition may be directly from the acquisition unit or may be from a storage unit 6 that previously received the first value 10, 11. The acquisition unit and / or the storage unit 6 may optionally be included in the system 2.

[0055] A first value 10 of a first body parameter BP1 and a first value 11 of a first subject characteristic parameter SCP1 relate to the measurement and / or determination of two values ​​10, 11 at a first time point T1.

[0056] The system 2 further comprises a first database DB1, which comprises values ​​of a first body parameter BP1 and a first subject characteristic parameter SCP1 for each of a plurality of individuals. As described above, the processing unit selects the first group of individuals 12 based on the similarity of the value of the first subject characteristic parameter SCP1 for each selected individual to the first value 11 of the subject individual 1.

[0057] The processing unit further determines a first mean or median M1 of the distribution of body parameter values ​​of the first body parameter BP1 for the individuals in the first group of individuals 12.

[0058] Furthermore, the processing unit is configured to determine a first deviation value D1 by determining a relationship between the first value 10 of the first body parameter BP1 and the first mean or median value M1. The first deviation value D1 may be provided as an absolute value of a difference between the first mean or median value M1 and the first value 10 of the first body parameter BP1.

[0059] At a second time point T2, a second value 20 of the first body parameter BP1 and a second value 21 of the second subject-characteristic parameter SCP2 are measured or determined. The second values ​​20, 21 are thus related to the measurements and / or determinations at the second time point. The processing unit is configured to acquire the second values ​​20, 21. The acquisition can be directly from an acquisition unit or can be from a storage unit that previously received the second values ​​20, 21. The acquisition unit and / or the storage unit can optionally be included in the system 2. In one embodiment, the second subject-characteristic parameter SCP2 is the same parameter as the first subject-characteristic parameter SCP1.

[0060] The system 2 further comprises a second database DB2. The second database DB2 comprises values ​​of the first body parameter BP1 and the second subject-characteristic parameter SCP2 for each of the plurality of individuals. As described above, the processing unit selects the second group of individuals 22 based on the similarity of the value of the second subject-characteristic parameter SCP2 of each selected individual to the second value 21 of the subject individual 1. Preferably, the first database DB1 and the second database DB2 are one and the same database.

[0061] The processing unit further determines a second mean or median value M2 of the first body parameter BP1 for the individuals in the second group of individuals 22.

[0062] Furthermore, the processing unit is configured to determine a second deviation value D2 by determining a relationship between the second value 20 of the first body parameter BP1 and the second mean or median value M2. The second deviation value D2 may be provided as an absolute value of a difference between the first mean or median value M2 and the second value 20 of the first body parameter BP1.

[0063] The first values ​​10, 11 relate to a first point in time T1 that is different from a second point in time T2 to which the second values ​​20, 21 relate. The two points in time T1, T2 preferably differ in time by at least 6 months or at least 12 months.

[0064] The acquisition of the first values ​​10, 11 and the second values ​​20, 21 may occur at a time different from the first and second points in time T1, T2. For example, the first values ​​10, 11 and the second values ​​20, 21 may be acquired by the processing unit at the same time, which is a time after the second point in time T2. The first values ​​10, 11 and the second values ​​20, 21 may be stored in a storage unit and acquired therefrom by the processing unit.

[0065] The processing unit is further configured to determine the body parameter change 30 by comparing the two deviation values ​​D1, D2, preferably by determining the difference between D1 and D2.

[0066] 2b illustrates an embodiment in which the processing unit is further configured to determine a first standard deviation SD1 of the distribution of body parameter values ​​for individuals in the first group of individuals and a second standard deviation SD2 of the distribution of body parameter values ​​for individuals in the second group of individuals. Furthermore, the first and second deviation values ​​D1, D2 are determined as first and second z-scores Z1, Z2. The first z-score Z1 is determined by dividing the difference between a first mean or median value M1 and a first value 10 of the body parameter BP1 by the first standard deviation SD1, providing a normalized value of the relationship between the first mean or median value M1 and the first value 10 of the body parameter BP1. The second z-score Z2 is determined by dividing the difference between a second mean or median value M2 and a second value 20 of the body parameter BP1 by the second standard deviation SD2, providing a normalized value of the relationship between the second mean or median value M2 and the second value 20 of the body parameter BP1.

[0067] FIG. 3 illustrates an embodiment in which a second body parameter BP2 is used as an additional input for determining a body weight-invariant body composition assessment standard for a subject individual 1. Such a method and system includes the same components as those described above for the first embodiment. Additionally, a processing unit acquires a first value 40 of the second body parameter BP2 at a first time point T1 and a second value 40 of the second body parameter BP2 at a second time point T2. Furthermore, first and second databases DB1 and DB2, which may be one and the same database, include values ​​of the second body parameter BP2 for each individual therein. A third mean or median M3 and a fourth mean or median M4 are thereby determined for the values ​​of the second body parameter BP2 of the first and second groups of individuals, respectively. Additionally, a third standard deviation SD3 and a fourth standard deviation SD4 are determined for the distribution of the values ​​of the second body parameter BP2 of the first and second groups of individuals, respectively. A third z-score Z3 is determined based on M3 and SD3. Based on M4 and SD4, a fourth z-score, Z4, is determined. The difference between Z3 and Z4 provides a second body parameter change 60. Thus, the second body parameter change can be combined with the first parameter change 30 to form a basis for body composition assessment.

[0068] As an example, the first body parameter BP1 may be the amount of visceral adipose tissue and the second body parameter BP2 may be the amount of liver fat. Thus, the combination of the body parameter changes 30, 60 for these two body parameters BP1, BP2 may provide a more complex view of the body composition of the subject individual 1.

[0069] 3 may alternatively be used to determine the absolute values ​​of four deviations between the mean or median values ​​M1-M4 and the values ​​10, 20, 40, 50 of the first and second body parameters BP1, BP2, instead of the four normalized z-scores Z1-Z4. Thus, the first and second body parameter changes 30, 60 may be determined by the differences between the determined deviations, replacing the z-scores Z1-Z4. This may eliminate the determination of standard deviations SD1-SD4.

[0070] FIG. 4 illustrates a method that may be performed by system 2 according to an alternative embodiment compared to FIGS. 2-3. Instead of determining z-scores Z1-Z4, mean or median values ​​M1, M2 are used to determine a predicted change value 70. Furthermore, first and second values ​​10, 20 of a first body parameter BP1 are used to determine a body parameter change value 80. The predicted change value 70 and the body parameter change value 80 are then compared to provide a body parameter change 30' that may serve as a basis for body composition assessment that is invariant to weight changes in the subject individual 1. In this embodiment, standard deviations SD1, SD2 do not need to be determined. Instead of basing the body parameter change 30 on a comparison of z-scores, the body parameter change 30' is determined by comparing the change in the body parameter values ​​10, 20 with the change in the mean or median values ​​M1, M2 from a reference group. Thus, the deviation between the predicted body parameter change 70 from the mean or median values ​​M1, M2 of the reference group and the actual body parameter change for the subject individual is determined. This provides a deviation in absolute value from the predicted change 70 based on the reference group. As an example, an individual subject may be determined to have lost, say, 2 liters more visceral adipose tissue than the reference group.

[0071] 5 illustrates a system 2 according to an embodiment of the present invention. The system 2 comprises a processing unit 4 configured to perform steps of the method as disclosed herein. Furthermore, the system 2 comprises a first database DB1 and a second database DB2. In the illustrated embodiment, the system 2 comprises a storage unit 6 configured to store values ​​10, 11, 20, 21, 40, 50 of the first body parameter BP1, the second body parameter BP2, the first subject-characteristic parameter SCP1, and / or the second subject-characteristic parameter SCP2. Thus, the processing unit 4 may retrieve one or more of the values ​​10, 11, 20, 21, 40, 50 from the storage unit 6.

[0072] In alternative embodiments, system 2 may not include storage unit 6. Instead, processing unit 4 may obtain one or more of the values ​​10, 11, 20, 21, 40, 50 from an external source. In one embodiment, system 2 may include an acquisition unit (not shown) via which processing unit 4 may obtain values ​​10, 11, 20, 21, 40, 50 from the external source. The storage unit 6 and external source embodiments may be combined, such that some values ​​are obtained from storage unit 6 and some values ​​are obtained from the external source.

[0073] The processing unit 4 is configured to output body parameter changes 30, 30', 60 to be used as a basis for body composition assessment invariant to weight changes.

[0074] In the drawings and specification, preferred embodiments and examples of the invention have been disclosed, and although specific terms have been employed, they are used in a generic and descriptive sense only and not for purposes of limitation; the scope of the invention is set forth in the following claims.

Claims

1. 1. A method (100) for providing a weight change invariant body composition assessment baseline for an individual subject (1), said method being performed by a processing unit, comprising: obtaining (101) a first value (10) of a body parameter (BP1) of said subject individual (1) at a first time point (T1), wherein said body parameter (BP1) is a parameter related to fat or muscle; obtaining (102) a second value (20) of said physical parameter (BP1) of said subject individual (1) at a second time point (T2) different from said first time point (T1); obtaining (103) a first value (11) of a first subject characteristic parameter (SCP1) of said individual subject at said first time point (T1), wherein said first subject characteristic parameter (SCP1) optionally comprises weight in combination with one or more of height, age, sex, ethnicity, BMI or other body measurements; obtaining (104) a second value (21) of a second subject characteristic parameter (SCP2) for said individual subject at said second time point (T2), wherein said second subject characteristic parameter (SCP2) optionally comprises weight in combination with one or more of height, age, sex, ethnicity, BMI and other body measurements; selecting (105) a first group (12) of individuals from a first database (DB1), wherein the first database comprises values ​​of the physical parameter (BP1) and the first subject characteristic parameter (SCP1) for each of a plurality of individuals, and the selection (105) of the first group (12) of individuals from the first database (DB1) is based on the similarity of the first subject characteristic parameter value for the selected individuals to the first value of the first subject characteristic parameter for the subject individuals; selecting (106) a second group (22) of individuals from a second database (DB2), wherein the second database comprises values ​​of the physical parameter (BP1) and the second subject characteristic parameter (SCP2) for each of the plurality of individuals, and wherein the selection (106) of the second group of individuals from the second database is based on the value of the second subject characteristic parameter of the selected individuals being similar to the second value of the second subject characteristic parameter for the subject individuals; determining (107) a first mean or median (M1) of the distribution of said body parameter values ​​for said individuals in said first group of individuals; determining (108) a second mean or median (M2) of the distribution of the body parameter values ​​for the individuals in the second group of individuals; determining (109) a first deviation value (D1) based on the relationship between the first mean or median value (M1) and the first value (10) of the physical parameter (BP1) of the individual subject; determining (110) a second deviation value (D2) based on the relationship between the second mean or median value (M2) and the second value (20) of the physical parameter (BP1) of the individual subject; determining (111) a first physical parameter change (30, 30') by comparing said first deviation value (D1) with said second deviation value (D2); A method for providing the above.

2. determining a first standard deviation (SD1) of the distribution of the body parameter values ​​for the individuals in the first group of individuals and a second standard deviation (SD2) of the distribution of the body parameter values ​​for the individuals in the second group of individuals; the first deviation value (D1) is a first z-score (Z1), and the step of determining (109) the first z-score (Z1) further comprises the step of dividing the difference between the first mean or median (M1) and the first value (10) of the physical parameter (BP1) by the first standard deviation (SD1); the second deviation value (D2) is a second z-score (Z2), and the step (110) of determining the second z-score (Z2) comprises dividing the difference between the second mean or median (M2) and the second value (20) of the physical parameter (BP1) by the second standard deviation (SD2); 2. The method of claim 1, wherein the first body parameter change (30) is determined by the difference between the first z-score (Z1) and the second z-score (Z2).

3. determining an expected change value (70) by comparing the first mean or median value (M1) with the second mean or median value (M2); and determining a physical parameter change value (80) by comparing the first value (10) of the physical parameter (BP1) with the second value (20) of the physical parameter (BP1), 3. The method of claim 1 or 2, wherein the step of determining (111) the body parameter change (30') is performed by comparing the predicted change value (70) with the body parameter change value (80).

4. 4. The method according to any one of claims 1 to 3, wherein said body parameter (BP1) is a parameter from the group of visceral adipose tissue mass, abdominal subcutaneous adipose tissue mass, liver fat mass, muscle volume, muscle fatty infiltration, organ volume and organ fatty infiltration.

5. 5. The method of any one of claims 1 to 4, wherein the first and second time points (T1, T2) are separated in time by at least 1 week, at least 1 month, at least 6 months, about 10-14 months, at least 12 months.

6. The method according to any one of claims 1 to 5, wherein the first subject characteristic parameter (SCP1) and the second subject characteristic parameter (SCP2) are the same subject characteristic parameter.

7. The method according to any one of claims 1 to 6, wherein said first subject characteristic parameter (SCP1) and / or said second subject characteristic parameter (SCP2) is weight in combination with gender.

8. The method according to any one of claims 1 to 5, wherein said first subject characteristic parameter (SCP1) and / or said second subject characteristic parameter (SCP2) is weight in combination with age.

9. 9. The method according to any one of claims 1 to 8, wherein the selection (105, 106) of the individuals of the first and / or second groups (12, 22) is performed by selecting individuals from the first and / or second databases (DB1, DB2) having values ​​of the first and / or second subject characteristic parameters (SCP1, SCP2) within a predetermined interval of the first and / or second values ​​(11, 21) of the first and / or second subject characteristic parameters (SCP1, SCP2) of the individual subjects (1).

10. 10. The method of claim 1, wherein the first database (DB1) and the second database (DB2) are the same database comprising values ​​of the physical parameter (BP1), the first subject characteristic parameter (SCP1), and the second subject characteristic parameter (SCP2) for each of the plurality of individuals therein.

11. 11. The method of any one of claims 2 to 10, wherein the step of determining (111) the body parameter change (30, 30') comprises determining the difference between the first z-score (Z1) and the second z-score (Z2), or the difference between the predicted change value (70) and the body parameter change value (80).

12. The method according to any one of claims 1 to 11, wherein the first and second values ​​(10, 20) of the body parameter (BP1) of the subject individual (1) are obtained on the basis of MRI.

13. 13. The method according to any one of claims 1 to 12, wherein the first group (12) and / or the second group (22) of individuals comprises at least 10, at least 50 or at least 100 individuals selected from the first database (DB1) and / or the second database (DB2).

14. The physical parameter (BP1) is a first physical parameter, and the method comprises: obtaining a first value (40) of a second body parameter (BP2) of said subject individual (1) at said first time point (T1), wherein said second body parameter (BP2) is a fat or muscle related parameter different from said first body parameter (BP1); obtaining a second value (50) of the second physical parameter (BP2) of the subject individual (1) at the second time point (T2); the first database (DB1) further comprises, for each of the plurality of individuals therein, a value of the second physical parameter (BP2); the second database (DB2) further comprises, for each of the plurality of individuals therein, a value of the second physical parameter (BP2); determining a third mean or median (M3) and a third standard deviation (SD3) of the distribution of the second physical parameter (BP2) for the individuals in the first group (10) of individuals; determining a fourth mean or median (M4) and a fourth standard deviation (SD4) of the distribution of the second physical parameter (BP2) for the individuals in the second group (22) of individuals; determining a third z-score (Z3) by dividing the difference between the third mean or median (M3) and the first value (40) of the second physical parameter (BP2) by the third standard deviation (SD3); determining a fourth z-score (Z4) by dividing the difference between the fourth mean or median (M4) and the second value (50) of the second physical parameter (BP2) by the fourth standard deviation (SD4); determining a second body parameter change (60) by determining the difference between the third z-score (Z3) and the fourth z-score (Z4); combining the first body parameter change (30) and the second body parameter change (60); The method of claim 2 or any one of claims 4 to 13 when dependent on claim 2, further comprising:

15. A system (2) for providing a basis for assessment of weight changes in a body parameter distribution for an individual subject, the system comprising: obtaining a first value (10) of a body parameter (BP1) of said subject individual (1) at a first time point (T1), wherein said body parameter (BP1) is a parameter related to fat or muscle; obtaining a second value (20) of the physical parameter (BP1) of the subject individual (1) at a second time point (T2) different from the first time point (T1); obtaining a first value (11) of a first subject characteristic parameter (SCP1) of said individual subject at said first time point (T1), wherein said first subject characteristic parameter (SCP1) optionally comprises weight in combination with one or more of height, age, sex, ethnicity, BMI or other body measurements; obtaining a second value (21) of a second subject characteristic parameter (SCP2) for said individual subject at said second time point (T2), wherein said second subject characteristic parameter (SCP2) optionally comprises weight in combination with one or more of height, age, sex, ethnicity and BMI; selecting a first group (12) of individuals from a first database (DB1), wherein the first database (DB1) comprises values ​​of the physical parameter (BP1) and the first subject characteristic parameter (SCP1) for each of a plurality of individuals, and the selection of the first group (12) of individuals from the first database (DB1) is based on the value of the first subject characteristic parameter for the selected individuals being similar to the first value of the first subject characteristic parameter for the subject individuals; selecting a second group (22) of individuals from a second database (DB2), wherein the second database (DB2) comprises values ​​of the physical parameter (BP1) and the second subject characteristic parameter (SCP2) for each of the plurality of individuals, and the selection of the second group (22) of individuals from the second database (DB2) is based on the second subject characteristic parameter value of the selected individual being similar to the second value of the second subject characteristic parameter for the subject individual; determining a first mean or median (M1) of the distribution of the body parameter values ​​for the individuals in the first group (12) of individuals; determining a second mean or median (M2) of the distribution of the body parameter values ​​for the individuals in the second group (22) of individuals; determining (109) a first deviation value (D1) based on a relationship between the first mean or median value (M1) and the first value (10) of the physical parameter (BP1) of the individual subject; determining (110) a second deviation value (D2) based on the relationship between the second mean or median value (M2) and the second value (20) of the physical parameter (BP1) of the individual subject; determining (111) a first body parameter change (30, 30') by comparing said first deviation value (D1) with said second deviation value (D2); A system comprising a processing unit configured to:

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