CPC G06T 7/38 (2017.01) [A61B 5/0042 (2013.01); A61B 5/0263 (2013.01); A61B 5/14542 (2013.01); G06T 7/0012 (2013.01); G06T 7/11 (2017.01); A61B 5/0205 (2013.01); A61B 5/026 (2013.01); A61B 5/055 (2013.01); A61B 5/4064 (2013.01); A61B 2576/026 (2013.01); G06T 2207/10088 (2013.01); G06T 2207/30016 (2013.01); G06T 2207/30104 (2013.01)]  19 Claims 
1. A method of assessing an abnormality in a test subject's vascular response to a vasoactive stimulus, the method comprising:
imposing at least one standardized change in arterial partial pressure of carbon dioxide in the test subject using a sequential gas delivery circuit, the at least one standardized change comprising a step change;
measuring test subject vascular response signals using a magnetic resonance imaging device, the test subject vascular response signals comprising at least a time course representing the test subject's vascular response to the at least one standardized change in arterial partial pressure of carbon dioxide in at least one region of interest of the test subject's brain;
calculating a score for the test subject, the score representing a comparison between the test subject vascular response signals for individual voxels in the at least one region of interest and respective computed statistical values per corresponding voxel, the respective computed statistical values representing a normal distribution of vascular response signals in a plurality of control subjects;
wherein the respective computed statistical values per corresponding voxel are computed based on a set of vascular response signals obtained for the plurality of control subjects, each vascular response signal representing a vascular response to at least one standardized change in arterial partial pressure of carbon dioxide per voxel in at least one common region of interest of each control subject's brain, the respective voxel coordinates coregistered to a standardized space based on a set of anatomic landmarks;
wherein the at least one standardized change in arterial partial pressure of carbon dioxide in the at least one region of interest of the test subject's brain is approximately the same as the at least one standardized change in arterial partial pressure of carbon dioxide per voxel in the at least one common region of interest of each control subject's brain; and
wherein the respective computed statistical values per corresponding voxel are computed by calculating a mean and a standard deviation of the vascular responses per voxel;
determining a probability that the test subject's vascular response is abnormal based on the score;
mapping the score onto an anatomical representation of the standardized space to generate a statistical map of the test subject's vascular response to the vasoactive stimulus; and
depicting, on a voxel by voxel basis, the probability that the test subject's vascular response is abnormal on the statistical map.
