Skeletal muscle microvascular flow in progressive peripheral artery disease: assessment with continuous arterial spin-labeling perfusion magnetic resonance imaging.
OBJECTIVE
We present the novel application of continuous arterial spin-labeling (CASL) magnetic resonance imaging (MRI) for the measurement of calf muscle perfusion in subjects with progressive peripheral arterial disease (PAD).


BACKGROUND
Peripheral arterial disease is largely considered to be a disease of conduit vessels. The impact of PAD upon microvascular flow in the end-organ, muscle, remains unknown. Continuous arterial spin-labeling is a noninvasive MRI method capable of measuring microvascular flow and might assist in our understanding of the impact of PAD upon the microvasculature.


METHODS
Forty subjects with varying degrees of PAD and 17 age-matched PAD-free subjects were recruited and underwent measurement of the ankle-to-brachial index (ABI) and CASL. Peak hyperemic flow (PHF) and time-to-peak (TTP) were computed and assessed as a function of ABI and calf muscle group.


RESULTS
An ABI dependence was found in both PHF (p = 0.04) and TTP (p < 10(-4)). Whereas TTP increased almost immediately with increasing PAD severity, PHF was, in contrast, relatively well preserved until later stages of disease.


CONCLUSIONS
The CASL flow measurements correlate with disease state as measured by ABI and demonstrate preserved microvascular flow reserve in the presence of early to intermediate vascular disease.
Wu
Wen-Chau
WC
Department of Radiology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Mohler
Emile
E
Ratcliffe
Sarah J
SJ
Wehrli
Felix W
FW
Detre
John A
JA
Floyd
Thomas F
TF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply; D018810:Magnetic Resonance Angiography; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply*; D016491:Peripheral Vascular Diseases / Q000175:diagnosis* / Q000503:physiopathology