Method To Diagnose and Measure Vascular Drainage Insufficiency in the Central Nervous System

Abstract

Neurodegenerative diseases, such as multiple sclerosis, may be caused or aggravated by insufficient venous draining from the central nervous system. Functional MRI measures the surge of blood flow into localized regions of cerebral cortex in response to activation of those regions by performing visual, auditory or executive tasks. These fMRI measurements are based on blood-oxygen-level dependence. The resulting fMRI/BOLD data is converted to hemodynamic response data and analyzed to determine any abnormality in the hemodynamic response data. Vascular drainage insufficiency is identified in the presence of abnormal hemodynamic response data. Abnormal hemodynamic response data can be determined by a negative trough in a graph of the HDR data or by the duration, depth, or area of the negative trough.

What is claimed is: 
     
         1 . A system for identifying abnormal hemodynamic responses, the system comprising:
 at least one hardware processor; and   one or more modules configured to, when executed by the at least one hardware processor,
 obtain a baseline blood-oxygen-level-dependence (BOLD) signal value, 
 obtain hemodynamic response data comprising a time series, wherein the time series comprises BOLD signal values over a time period for the one or more regions of interest of a subject's brain, 
 identify a negative trough in the hemodynamic response data, wherein the negative trough comprises a portion of the time period during which the BOLD signal values of the time series are less than the baseline BOLD signal value, and 
 determine whether the hemodynamic response data represents an abnormal hemodynamic response based on the identified negative trough. 
   
     
     
         2 . The system of  claim 1 , wherein the one or more modules are further configured to obtain functional magnetic resonance imaging (“fMRI”) data over the time period for the one or more regions of interest of the subject's brain, and wherein obtaining the hemodynamic response data comprises generating the hemodynamic response data based on the fMRI data. 
     
     
         3 . The system of  claim 2 , wherein the one or more modules are further configured to obtain structural magnetic resonance imaging (MRI) data for the one or more regions of interest of the subject's brain, and wherein obtaining the baseline BOLD signal value comprises generating the baseline BOLD signal value based on the structural MRI data. 
     
     
         4 . The system of  claim 2 , wherein the fMRI data comprises images of the subject's brain captured while the subject performed a single task, followed by a first time interval, followed by a block of multiple tasks, followed by a second time interval. 
     
     
         5 . The system of  claim 4 , wherein the negative trough comprises at least a portion of the second time interval during which the BOLD signal values of the time series are less than the baseline BOLD signal value. 
     
     
         6 . The system of  claim 4 , wherein the single task and the multiple tasks each comprise the same task, and wherein the task comprises providing one of two possible responses. 
     
     
         7 . The system of  claim 1 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on a duration of the identified negative trough. 
     
     
         8 . The system of  claim 1 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on a depth of the identified negative trough. 
     
     
         9 . The system of  claim 1 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on an area of the identified negative trough. 
     
     
         10 . A method for identifying abnormal hemodynamic responses, the method comprising using at least one hardware processor to:
 obtain a baseline blood-oxygen-level-dependence (BOLD) signal value;   obtain hemodynamic response data comprising a time series, wherein the time series comprises BOLD signal values over a time period for the one or more regions of interest of a subject's brain;   identify a negative trough in the hemodynamic response data, wherein the negative trough comprises a portion of the time period during which the BOLD signal values of the time series are less than the baseline BOLD signal value; and   determine whether the hemodynamic response data represents an abnormal hemodynamic response based on the identified negative trough.   
     
     
         11 . The method of  claim 10 , further comprising obtaining functional magnetic resonance imaging (“fMRI”) data over the time period for the one or more regions of interest of the subject's brain, and wherein obtaining the hemodynamic response data comprises generating the hemodynamic response data based on the fMRI data. 
     
     
         12 . The method of  claim 11 , further comprising obtaining structural magnetic resonance imaging (MRI) data for the one or more regions of interest of the subject's brain, and wherein obtaining the baseline BOLD signal value comprises generating the baseline BOLD signal value based on the structural MRI data. 
     
     
         13 . The method of  claim 11 , wherein the fMRI data comprises images of the subject's brain captured while the subject performed a single task, followed by a first time interval, followed by a block of multiple tasks, followed by a second time interval. 
     
     
         14 . The method of  claim 13 , wherein the negative trough comprises at least a portion of the second time interval during which the BOLD signal values of the time series are less than the baseline BOLD signal value. 
     
     
         15 . The method of  claim 13 , wherein the single task and the multiple tasks each comprise the same task, and wherein the task comprises providing one of two possible responses. 
     
     
         16 . The method of  claim 10 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on a duration of the identified negative trough. 
     
     
         17 . The method of  claim 10 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on a depth of the identified negative trough. 
     
     
         18 . The method of  claim 10 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on an area of the identified negative trough. 
     
     
         19 . A non-transitory computer-readable medium having one or more sequences of instructions stored thereon, wherein the one or more sequences of instructions are configured to, when executed by a processor, cause the processor to:
 obtain a baseline blood-oxygen-level-dependence (BOLD) signal value;   obtain hemodynamic response data comprising a time series, wherein the time series comprises BOLD signal values over a time period for the one or more regions of interest of a subject's brain;   identify a negative trough in the hemodynamic response data, wherein the negative trough comprises a portion of the time period during which the BOLD signal values of the time series are less than the baseline BOLD signal value; and   determine whether the hemodynamic response data represents an abnormal hemodynamic response based on the identified negative trough.   
     
     
         20 . The non-transitory computer-readable medium of  claim 19 , wherein the determination of whether the hemodynamic response data represents an abnormal hemodynamic response is based, at least in part, on one or more of a duration of the identified negative trough, a depth of the identified negative trough, and an area of the identified negative trough.