Time-Resolved Contrast-Enhanced Magnetic Resonance Angiography of the Lower Extremity

Abstract

The aim of this prospective study was to evaluate the feasibility and clinical use of time-resolved magnetic resonance angiography (MRA) of the lower extremity compared to intraarterial digital subtraction angiography (IA-DSA). Twenty-two patients suffering from peripheral arterial occlusive disease underwent MRA and IA-DSA. MRA examinations were performed on a 1.5 T system equipped with a 4-element-array coil. The area from the distal abdominal aorta to the distal lower limb was covered by 2-3 examination steps. A T1-weighted gradient echo sequence with a temporal resolution of 7-10 s was used. Single-dose contrast material (0.1 mm/kg) was injected with a flow rate of 2 mL/s, followed by a 40 mL saline flush. Pre and post contrast images were subtracted, and the subtracted data set was postprocessed with maximum intensity projection (MIP). In all patients diagnostic images could be obtained. Problems with venous overlay or incomplete arterial filling were not present. Sensitivity for the detection of relevant stenoses (>50%) was 96.7%, specificity was 97%. Concerning the detection of occlusions, sensitivity was 97.8%, specificity was 99.2%. Time-resolved contrast-enhanced MRA of the lower extremity is a robust procedure with high accuracy in the detection of relevant stenoses and occlusions.

Single‐dose time‐resolved contrast enhanced hybrid MR angiography in diagnosis of peripheral arterial disease: Compared with digital subtraction angiography

“…Our study showed comparable results of average sensitivity of 95% and specificity of 91% with 93% accuracy, respectively. The interobserver agreements on MRA in our study for all grades of arterial stenosis (grades 1–4) with linear weighting is good (k = 0.77), while excellent for hemodynamically significant stenosis without weighting (k = 0.82), which were comparable to the data reported in the literature (14–16, 24).…”

“…To eliminate the possible venous contamination, and to ensure optimal imaging of each leg in patients where transit times to one foot are markedly different from those to the other, time‐resolved imaging of contrast kinetics (TRICKS) sequence of MRA with three separate contrast injections was initially applied (14, 15, 24). The short acquisition time of 6–10 s with up to 20 phases can take images from early arterial phase to venous phase with the diagnostic sensitivity of 89–97%, and specificity of 97–98%, respectively (14, 15). Andreisek et al performed a hybrid technique combining bolus‐chase and TRICKS sequences by two separate contrast injections also obtained a good diagnostic performance (16).…”

“…They concluded that for the preservation of residual renal function and avoidance of NSF in patients with renal insufficiency, administering single‐dose instead of double‐dose gadolinium‐based contrast agents could be safe when performing MRI or MRA. The conventional dose of gadolinium‐based contrast medium for bolus‐chase MRA is double or triple dose, while at least two to three single doses for TRICK or hybrid MRA (14–16, 18, 23, 25–28). In the present study, although, two separate injections of contrast agent are required for the hybrid MRA, with half of the dose (0.05 mmol/kg) in each session, it totaled one single‐dose contrast injection.…”

“…To eliminate the possible venous contamination, investigators had used time‐resolved imaging of contrast kinetics (TRICKS) pulse sequence by three separate contrast injections for pelvis and lower limb arteries with excellent diagnostic performance(14, 15). Recently, Andreisek et al applied a hybrid technique, combining bolus‐chase and TRICKS sequences, with two separate contrast injections in PAD patients (16).…”

3D contrast‐enhanced MR angiography

“…Sufficient saline flush also helps to lengthen the contrast bolus (62). Suggested flush volumes are 15–50 mL, with most authors using 20 mL (63, 64).…”