Clinical Evaluation of Peripheral Vascular Disease Using a Hybrid Approach: Unenhanced Quiescent Interval Single Shot and Low-Dose TWIST MR Angiography

Philip Anthony Hodnett^1,2, Ioannis Kokztzoglou³, Timothy Scanlon, Jeremy Collins⁴, John Sheehan, Eugene Dunkle, James C. Carr, Robert Edelman

Imtroduction:The purpose of this study was to test the hypothesis that a hybrid technique employing a new unenhanced MRA technique, quiescent interval single shot (QISS) in combination with a low-dose time resolved (TWIST)of the calf provides comparable diagnostic accuracy to the standard hybrid approach using low-dose TWIST of the calf and high-dose stepping table CE-MRA. Materials and Methods:20 prospective patients referred for evaluation of peripheral arterial disease underwent unenhanced and combined low-dose time-resolved (TWIST)evaluation followed by standard hybrid stepping table bolus chase MRA. Results:The combined unenhanced QISS technique and low-dose time resolved (TWIST ) calf study resulted in an overall sensitivity of 97.4%, specificity of 98.3%, a negative predictive value of 98.7% and a positive predictive value of 96.7% using CE-MRA as the reference standard. Cohen kappa analysis for inter-rater indicates almost perfect agreement (= 0.86) between the hybrid approach of unenhanced QISS and TWIST and standard hybrid CE-MRA. Conclusion: This hybrid strategy permits a dramatic reduction in contrast agent dosage with no loss of diagnostic accuracy.