After institutional review board approval and informed consent were obtained for this HIPAA-compliant investigation, a three-dimensional electrocardiographically gated variable flip angle (VFA) fast spin-echo magnetic resonance (MR) angiography technique was evaluated as an unenhanced method for imaging hand arteries in 13 subjects (including four patients) at 3.0 T; this included evaluation of vessel visualization with warming and cooling in seven subjects. Examinations were evaluated for image quality and vessel conspicuity. Clear separation of arteries from veins was achieved in all subjects, with excellent vessel conspicuity and depiction of stenoses. Warming improved vessel visualization in healthy volunteers. VFA MR angiography is a high-spatial-resolution technique that enables the assessment of vascular reactivity in response to temperature challenge. RSNA, 2009 1 From the Department of Radiology (MRI), New York University Langone Medical Center, 530 First Ave, Basement Schwartz Bldg, New York, NY 10016 (R.P.L., P.S., I.P.A., E.M.H., J.S.B., D.R.S., K.M., Q.C., H.R., V.S. Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, use the Radiology Reprints form at the end of this article.I maging is vital in the work-up and management of vascular hand abnormalities, including thromboembolic disease, vasculitides, trauma, and vascular malformations. The standard of reference for hand evaluation is digital subtraction angiography (1). However, digital subtraction angiography has associated risks of puncture site complications, ionizing radiation, and iodine nephrotoxicity and can also be a painful procedure for patients. In addition, vasodilators are frequently required for optimal visualization of the small arteries of the hand, which are highly reactive to noxious stimuli (2). Contrast materialenhanced magnetic resonance (MR) angiography has been advocated as a suitable noninvasive alternative (3-5), but small vessel caliber, relatively slow arterial flow, and short arteriovenous transit times can hamper arterial visualization (1,6). Attempts to shorten imaging times can compromise spatial resolution or signal-to-noise ratio.An unenhanced technique is desirable, particularly in patients with vasculitides or concurrent renovascular disease, in whom renal function may be compromised and nephrogenic systemic fibrosis becomes a potential clinical concern (7). Time-of-flight and phase-contrast techniques have been reported (8) but are limited by long imaging times and limited coverage (1).An electrocardiographically gated spin-echo-based MR angiographic technique was initially described by Wedeen et al (9) and was later adapted into a three-dimensional (3D) single-shot fast spin-echo (FSE) technique by Miyazaki et al (10) on the basis of the principle that black blood images can be obtained in fast-flowing blood with spin-echo sequences.Promising results have been obtained with this technique for the lower extremities (1...