Comparison of auto-moving table contrast-enhanced 3-D MRA and iodinated contrast-enhanced DSA for evaluating the lower-extremity arteries.

BACKGROUND: This study was conducted to compare diagnostic efficacy of contrast-enhanced 3-dimensional magnetic resonance angiography (3-D MRA) with that of the conventional x-ray iodinated digital subtraction angiography (DSA) in patients with peripheral arterial occlusive diseases (PAOD). METHODS: Twenty patients with a clinical diagnosis of PAOD participated in this study. All patients were evaluated with both contrast-enhanced 3-D MRA and conventional x-ray iodinated DSA for the arteries of their lower extremities. The DSA was performed by a selective catheterization into the bilateral common or superficial femoral arteries, whereas 3-D MRA was performed with an auto-moving table covering the vascular tree from aorta to the arteries of ankle regions with 1 bolus injection of a triple-dose (0.3 mmol/kg) contrast medium. The arteries were divided into 23 anatomic segments and graded by their appearance on a 1-4 scale (1 = normal, 4 = total occlusion or no visible vessel). Evaluators also compared the images of 3-D MRA with those of the conventional x-ray iodinated DSA (as gold standard) with respect to image quality. RESULTS: There was a high agreement (k = 0.6-1.0) between 2 observers' interpretations of the images obtained from 3-D MRA and conventional DSA. The agreement within each observer was moderate to fair (k = 0.32-0.57), and the better agreement was found with the images above knee level than those below knee level. As for the image quality of 3-D MRA, the frequencies of showing a similar image quality were 57.5%, 55%, and 37.5% at the aortofemoral, femoropopliteal, and distal leg levels, respectively. CONCLUSIONS: The main problem of the 3-D contrast enhanced MRA was the returned venous contamination of the image. It was particularly problematic for the areas below knee level. MRA can provide an initial evaluation for patients with PAOD, but cannot substitute for the conventional DSA as a precise diagnostic image modality for peripheral vascular diseases, especially for the distal legs.

Carbon dioxide angiography in lower limbs: a prospective comparative study with selective iodinated contrast angiography.

This was a prospective comparison of the accuracy and image quality of carbon dioxide digital subtraction angiography (CO2 DSA) and iodinated contrast digital subtraction angiography (ICDSA) in evaluating lower extremity arteries and patient tolerance of the procedures. Selective DSA was performed in 14 Taiwanese patients who were diagnosed with peripheral artery occlusive disease (PAOD). Both contrast materials were administered through mechanical injectors. Post-processing of the image used pixel shifting. Images of vessels were divided into 22 anatomic segments and evaluated by two experienced radiologists. A four-point scale was used to classify diseased vessels. Two interpreters rated the CO2 DSA image against the ICDSA image on a three-point scale. Patient tolerance was assessed from verbal descriptions. Cohen's kappa was used to determine interobserver agreement and descriptive statistics were used to summarize patient experience. Interobserver agreement ranged from fair to excellent, with most being good or excellent. Three patients (21.4%) could not tolerate the whole procedure and nine patients (64.3%) reported discomfort during the CO2 DSA procedure. CO2 DSA image quality was better for the thigh than the distal runoff and pelvic regions. Our results showed that selective CO2 DSA cannot replace ICDSA as a routine diagnostic tool for PAOD because it does not give images of comparative quality.