Infrared imaging reveals differential vascular post-occlusive response in sickle cell anemia

Thursday, November 07, 2013 — Poster Session II
12:00 p.m. – 2:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NIBIB	BIOENG-4

Authors

M.D. Antalek
M.L. Seidel
T.P. Darlington
K. Chang
A. Ikeda
C. Seamon
G. Kato
H. Ackerman
A.M. Gorbach

Abstract

Sickle cell anemia (SCA) is a hereditary disorder characterized by the obstruction of blood flow by rigid, sickle-shaped blood cells. To identify possible dysfunction in the microvasculature, transient increases in forearm blood flow following 5-min periods of arterial occlusion were compared between SCA patients (n=31) and healthy volunteers (HV, n=38). This well-known post-occlusive reactive hyperemia (PORH) test was augmented by introducing continuous mapping of forearm temperature (volar aspect) by passive infrared camera (640x512 pixels per image, 0.01˚C temperature resolution). Each test included a 30-min baseline, 5-min of forearm occlusion and 15-min of reperfusion. To define regions of interest (ROIs) consisting of early and late responding highly reactive forearm vasculature, k-means clustering was applied off-line to select only those pixels that showed the highest rate of temperature change during reperfusion. For each patient, a time-temperature profile of the reactive vessels was calculated by taking an ensemble average across all pixels within the ROIs. Preliminary data showed that identified PORH markers, such as time from peak rate of temperature increase to temperature maximum, and baseline-corrected temperature recovered 20 seconds after its maximum, were statistically different between the SCA and HV groups (p<0.05) within early and late responding ROIs.