Differences in skin vasomotion between patients with sickle cell anemia and healthy volunteers: a laser speckle imaging study.

Friday, November 08, 2013 — Poster Session III
10:00 a.m. – 12:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NIBIB	CLIN-28

Authors

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

Abstract

Laser speckle contrast imaging (LSCI) was conducted as a non-invasive means of quantifying vasomotion in healthy volunteers (HV), and sickle-cell anemia patients during steady-state (SCA-ST) and in pain crisis (SCA-CR). Vasomotion is a natural oscillation in vessel tone, independent of heart rate, that enhances oxygen delivery to tissues and is controlled by the sympathetic nervous system, local myogenic mechanisms, and endothelium-derived nitric oxide and hyperpolarizing factors, each purportedly resulting in different oscillatory frequencies. Baseline images (9000 images; 152x113 pixels each) of the volar forearm were collected over 30 minutes. Following image registration, each pixel’s time-flux profile was de-trended, filtered, and analyzed for oscillatory power using FFT. Ensemble averaging across pixels yielded an average single-pixel power spectrum for each subject. Preliminary results indicated that, compared with HV, SCA-ST had higher total oscillatory power and higher relative oscillatory power within the 0.07-0.09 Hz frequency sub-range. SCA-CR patients had higher total power than SCA-ST, but were similar to HV in relative oscillatory power within the 0.07-0.09 Hz sub-range. Based on the literature, vasomotions at these frequencies reflect local myogenic control of peripheral microvasculature, and we speculate that differences among these groups arise from interactions between rigid blood cells and the vascular wall.