Two-station bolus-chase MR angiography with a stationary table: a simple alternative to automated-table techniques.

Abstract

Our purpose was to evaluate a simple, two-station, bolus-chase, peripheral MR angiography technique that relies on manual patient translation using a plastic patient-transfer board. Twenty patients successfully completed both lower extremity MR angiography and digital subtraction angiography within a 3-month period. For MR angiography, patients were placed on the scanner table on a standard plastic patient-transfer board. We performed unenhanced and contrast-enhanced imaging at the level of the pelvis using a three-dimensional gradient-echo sequence (TR range/TE range, 3.8-4.6/1.3-1.8; flip angle range, 25-40 degrees ). Then patients were quickly pulled 350-400 mm using the transfer-board handles, and two subsequent acquisitions were obtained at the level of the thighs. For each modality, two radiologists who were unaware of correlative imaging results retrospectively scored all vessel segments as either greater than or equal to 50% stenosis or less than 50% stenosis, and interobserver agreement was determined. Using digital subtraction angiography as the standard of reference, we used consensus data to compute MR angiography sensitivity and specificity. In the 261 vessel segments considered, MR angiography had a sensitivity of 75% (12/16) and a specificity of 98% (94/96) for the detection of stenosis greater than or equal to 50% from the aorta through the common femoral arteries. For the superficial and profunda femoral arteries through the popliteal arteries, these values were 97% (31/32) and 94% (34/36), respectively. MR angiography interobserver agreement for detection of stenosis was good (kappa = 0.68) for the aorta through the common femoral arteries and excellent (kappa = 0.88) for the superficial and profunda femoral arteries through the popliteal arteries. These values were comparable to those found for digital subtraction angiography (kappa = 0.67 and kappa = 0.88, respectively). Stationary-table MR angiography is a useful, simple strategy for lower extremity angiography in centers without a moving table.