Carotid MR angiography: Phase II study of safety and efficacy for MS-325

PURPOSE: To evaluate the safety and efficacy of MS-325 in patients suspecte d of having carotid arterial disease. MATERIALS AND METHODS: Fifty carotid arteries in 26 patients were imaged wi th three-dimensional spoiled gradient-recalled-echo magnetic resonance (MR) angiography at 5 and 50 minutes after injection of MS-325. MS-325 was admi nistered intravenously as a single dose of 0.01, 0.03, or 0.05 mmol per kil ogram of body weight as determined with a dose randomization scheme for fou r, nine, and 13 patients, respectively. Safety, including clinical laborato ry changes and electrocardiographic monitoring, was assessed until approxim ately 3 days after injection. Conventional contrast agent-enhanced angiogra phy was used as the standard of reference. Independent readers blinded to t he dose interpreted the MR angiographic and conventional images. Images wer e assessed for location and extent of carotid arterial stenosis. RESULTS: There were no severe or serious adverse events. For the determinat ion of clinically significant stenosis (>70%) on the 5-minute images, sensi tivity, specificity, and accuracy (P = .07, three-way comparison) were 100% , 100%, and 100%; 63%, 100%, and 88%; and 40%, 75%, and 55% at 0.01, 0.03, and 0.05 mmol/kg, respectively. Sensitivity and specificity for images at 5 0 minutes after MS-325 administration showed the same trends as the 5-minut e images. CONCLUSION: Overall accuracy for MS-325-enhanced carotid MR angiography per formed during steady-state conditions of circulating contrast agent approxi mately 5 minutes after injection was high (88%-100%) at 0.03 and 0.61 mmol/ kg. MS-325 was well tolerated at all evaluated doses.