MAGNETIC-RESONANCE ANGIOGRAPHY IN THE MANAGEMENT OF LOWER-EXTREMITY ARTERIAL OCCLUSIVE DISEASE - A PROSPECTIVE-STUDY

Purpose: We conducted a prospective study to clarify the clinical util ity of magnetic resonance angiography (MRA) in the treatment of patien ts with lower extremity arterial occlusive disease. Methods: During th e interval of September 1993 through March 1995, 79 patients (43% clau dicants, 57% limb-threatening ischemia) were studied with both MRA and contrast arteriography (ANGIO) and underwent intervention with either balloon angioplasty (9%), surgical inflow (28%), or outflow (63%) pro cedures. MRA and ANGIO were interpreted by separate blinded vascular r adiologists, and arterial segments from the pelvis to the foot were gr aded as normal or with increasing degrees of mild (25% to 50%), modera te (51% to 75%), or severe (75% to 99%) stenosis or occlusion. Treatme nt plans were formulated by the attending surgeon and were based initi ally on hemodynamic, clinical, and MRA. data and thereafter with ANGIO . Additional study surgeons formulated independent and specific treatm ent plans based on MRA or ANGIO alone. Indexes of agreement (beyond ch ance) for arterial segments depicted by MRA and ANGIO were assessed (k appa value), and treatment plans formulated were compared (chi-square) . Results: Precise agreement (%) and the percent of major discrepancie s (segment classified as normal/mild stenosis on one study and severe stenosis/occlusion on the other) between MRA and ANGIO for respective arterial segments was as follows: common and external iliacs (n = 256) 77/3.5; superficial femoral and above-knee popliteal (n = 255) 73/6.7 ; below-knee popliteal (n = 131) 84/3.8; infrapopliteal runoff vessels (n = 864) 74/12.4; pedal vessels (n = 111) 69/19.8 Kappa values indic ated moderate agreement (between MRA. and ANGIO) beyond chance for all arterial segments. Treatment plans formulated by the attending surgeo n, the MRA surgeon, and the ANGIO surgeon agreed in more than 85% of c ases. Inability of MRA. to assess the significance of inflow disease a nd inadequate detail of tibial/pedal vessels were the principal defici encies of MRA in those cases where it was considered an inadequate exa mination. Conclusion: These findings suggest MRA and ANGIO are nearly equivalent examinations in the demonstration of infrainguinal vascular anatomy. MRA is an adequate preoperative imaging study (and may repla ce ANGIO), particularly in those circumstances when the risk of ANGIO is increased or when clinical and hemodynamic evaluation predict the l ikelihood of straightforward aortofemoral or femoral-popliteal reconst ruction.