MULTICENTER TRIAL TO EVALUATE VASCULAR MAGNETIC-RESONANCE ANGIOGRAPHYOF THE LOWER-EXTREMITY

Objectives.-To assess the value of magnetic resonance angiography (MRA ) in presurgical evaluation of patients with severe lower limb atheros clerotic occlusive disease and to assess the feasibility of rapidly co nducting rigorous technology assessment. Design.-Blinded, prospective study of consecutive patients with signs or symptoms of severe infrain guinal peripheral vascular disease who were candidates for percutaneou s or surgical intervention, Using both descriptive statistics and mult ivariate logistic analyses, MRA was compared with contrast arteriograp hy (CA) (the current technique) for imaging 15 arterial segments of th e leg and foot. Intraoperative contrast angiography was the ''gold'' s tandard. Also studied was the effect of adding MRA to the information used in planning treatment.Setting.-Six US hospitals, one a community hospital. Patients.-A total of 155; 84% with either rest pain or tissu e loss. Results.-Sensitivity in distinguishing patent segments from co mpletely occluded segments was 83% for CA and 85% for MRA; both had 81 % specificity, For distinguishing near-normal segments (suitable as by pass graft termini), CA was less sensitive than MRA (77% vs 82%), but more specific (92% vs 84%). After adjusting for same-reader effects, o dds of correctly distinguishing patent segments were 1.6 times as grea t for MRA as for CA (P<.01); for distinguishing near-normal segments, the odds for CA were 1.5 times as great as for MRA (P<.05). The additi on of MRA changed the treatment plan in 13% of patients; in 86% of the se cases, the surgery actually performed indicated that the MRA-inclus ive plan was superior. Conclusions.-Individually, MRA and CA are appro ximately equivalent in diagnostic accuracy, The addition of MRA to tre atment plans based only on CA and other diagnostic information clearly improves the plans. Completed in 15 months (as planned), our study de monstrates the feasibility of conducting rigorous technology assessmen t rapidly enough to be timely even in fields in which diagnostic and t reatment techniques are rapidly changing.