Tuesday, December 11, 2018

Diagnostic accuracy of noncontrast MR angiography protocols at 3T for the detection and characterization of lower extremity peripheral arterial disease


Summary


A clinical study evaluating non-contrast magnetic resonance angiography (MRA) to gadolinium (Gd)-based contrast MRA for lower extremity peripheral artery disease (PAD) in 20 patients was performed at 3T (vs. 1.5 T as most published diagnostic accuracy studies). Two established non-contrast MRA protocols were compared to conventional Gadolinium (Gd)-contrast enhanced MRA: (1) Quadruple inversion-recovery (QIR) Electrocardiogram combined with (ECG)-gated fast spin echo (ECG-FSE) and (2) quiescent-interval single-shot (QISS).

Imaged patients (n = 20) had intermittent claudication (Fontaine stage II) with an ankle-brachial index of < 0.9. Exclusion criteria included rest pain, nonhealing ulcers, estimated glomerular filtration rate < 30 mL/min/1.73 m2, pregnancy, claustrophobia, clinical instability or any contraindication to 3T MR imaging.

In this study, imaging datasets were reviewed in a blinded fashion by two radiologists. Non-Gd protocols demonstrated comparable diagnostic accuracy with high specificity compared to Gd-MRA protocols.


Commentary


The authors present a well-designed study evaluating forthcoming techniques in non-contrast enhanced MRA for the evaluation of lower extremity peripheral vascular disease. The techniques demonstrate information comparable to conventional contrast-enhanced MRA.

In the PAD patient population, a tool obviating the need for contrast is attractive as patients regularly have concomitant degrees of renal dysfunction. Ultimately, this study demonstrated that non-contrast MRA is a promising vascular imaging tool.

Limitations appropriately addressed by the authors include patient characteristics that may prevent or limit application of MR imaging, including body habitus, inability to follow breathing instructions, or claustrophobia. Furthermore, comparative imaging and information with non-MR focused vascular imaging tools was not performed.

Post Author:
David M. Tabriz, MD
Assistant Professor
Rush University Medical Center
@DrDaveTabriz

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