Assessment of lower extremity peripheral arterial occlusive disease (PAOD): Comparison of contrast enhanced-3D magnetic resonance angiography and digital subtraction angiography/ digital angiography

Abstract

Objective : The purpose of this study was to evaluate the diagnostic accuracy of contrast-enhanced 3D MR angiography (CE-3D MRA), using digital subtraction angiography (DSA) or digital angiography (DA) as a gold standard, in patients with lower extremity peripheral arterial occlusive disease (PAOD) at King Chulalongkorn Memorial Hospital.

Materials and Methods : Two hundred fifty - three arterial segments from 19 patients (21 studies) underwent both CE-3D MRA and DSA/DA retrospectively. CE-3D MRA protocol was performed at three levels-: the abdomen-pelvis- and the thigh, using bolus trigger technique with two-step moving table, and the leg to proximal foot, using time-resolved imaging of contrast kinetics (TRICKS) sequence. The results were reviewed using maximum-intensity-projection (MIP) CE-3D MRA compared with DSA/DA of the matching arterial segments to the CE-3D MRA studies. The vessels were reviewed from abdomen to legs which were divided into 16 segments on each side. The degree of stenosis of each segment was graded as normal or stenosis less than 50%, stenosis more than 50% and occlusion. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) ofCE-3D MRA were calculated using DSA/DA as the gold standard. The run - off vessels demonstrated in both studies were also evaluated.

Results : Among 253 analyzed segments, the accuracy, sensitivity, specificity, PPV and NPV of CE - 3D MRA in depicting arterial occlusion and stenosis that is greater than 50%) were 77.47%, 85.57%, 80.13%, 72.81% and 89.93%, respectively. The total numbers of run - off segments detected by CE-3D MRA were 23/33 (69.7%)) segments (6 suprapopliteal and popliteal vessels, 17 infrapopliteal vessels): 14/33 (42.42%>) segments (7 suprapopliteal and popliteal vessels, 7 infrapopliteal vessels) detected by DSA/DA. Nineteen (57.58%)) run - off segments were observed on CE-3D MRA that were not detected on DSA/DA.

Conclusion : CE-3D MRA is a reliable method for investigating peripheral arterial disease in selected patients with lower extremity PAOD with very high NPV and can depict run-off arteries not seen on DSA/DA in case of occlusion.