Classification of spatiotemporal hemodynamics from brain perfusion MR images using expectation-maximization estimation with finite mixture of multivariate gaussian distributions.
The ability to cluster different perfusion compartments in the brain is critical for analyzing brain perfusion. This study presents a method based on a mixture of multivariate Gaussians (MoMG) and the expectation-maximization (EM) algorithm to dissect various perfusion compartments from dynamic susceptibility contrast (DSC) MR images so that each compartment comprises pixels of similar signal-time curves. This EM-based method provides an objective way to 1) delineate an area to serve as the in-plane arterial input function (AIF) of the feeding artery for adjacent tissues to better quantify the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT); 2) demarcate regions with abnormal perfusion derangement to facilitate diagnosis; and 3) obtain parametric maps with supplementary information, such as temporal scenarios and recirculation of contrast agent. Results from normal subjects show that perfusion cascade manifests (in order of appearance) the arteries, gray matter (GM), white matter (WM), veins and sinuses, and choroid plexus mixed with cerebrospinal fluid (CSF). The averaged rCBV, rCBF, and MTT ratios between GM and WM are in good agreement with those in the literature. Results from a patient with cerebral arteriovenous malformation (CAVM) showed distinct spatiotemporal characteristics between perfusion patterns, which allowed differentiation between pathological and nonpathological areas.
Wu
Yu-Te
YT
Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, Republic of China. ytwu.edu.tw
Chou
Yen-Chun
YC
Guo
Wan-Yuo
WY
Yeh
Tzu-Chen
TC
Hsieh
Jen-Chuen
JC
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000098:blood supply* / Q000473:pathology*; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D018810:Magnetic Resonance Angiography / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D016011:Normal Distribution; D012016:Reference Values