title: Lower extremity: low-dose contrast agent intraarterial MR angiography in patients--initial results.
abstract: Institutional review board approval and patient consent were obtained. A low-dose injection protocol for intraarterial three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiography was derived from femoral flow phantom studies and prospectively evaluated in patients with peripheral arterial occlusive disease (PAOD). All MR angiograms were obtained at 1.5 T with a T1-weighted gradient-echo sequence. MR angiograms of a gadolinium dilution series (0.8-200.0 mmol/L) were acquired in a femoral phantom at different flow rates. Signal-to-noise ratios (SNRs) above the 75% threshold of the measured maximum were considered optimal. The lowest optimal concentration was injected intraarterially in nine patients to obtain 3D MR angiograms of the thigh and calf station. Contrast-to-noise ratios (CNRs) were calculated for four arterial segments. The low optimal concentration of 50 mmol/L (20-mL bolus volume), about 5% of the total permissible dose, showed SNRs larger than the 75% threshold in the phantom study. In patients, this concentration led to high-spatial-resolution angiograms with mean CNRs of 70.0 +/- 14.5 (+/- standard deviation) for the superficial femoral artery and 47.5 +/- 13.4 at the infrapopliteal level. Low-dose contrast agent intraarterial 3D MR angiography showed high arterial enhancement, enabling assessment of lower extremity arteries in patients with PAOD and multiple injections--a crucial precondition for MR-guided endovascular interventions.
authors.affiliation: Department of Diagnostic Radiology, University of Basel, Petersgraben 4, CH-4031 Basel, Switzerland. dbilecen@uhbs.ch
authors.forename: Deniz
authors.initials: D
authors.lastname: Bilecen
authors.forename: Anja-Carina
authors.initials: AC
authors.lastname: Schulte
authors.forename: Hanns G
authors.initials: HG
authors.lastname: Heidecker
authors.forename: Markus
authors.initials: M
authors.lastname: Aschwanden
authors.forename: Rolf
authors.initials: R
authors.lastname: Huegli
authors.forename: Kurt A
authors.initials: KA
authors.lastname: Jaeger
authors.forename: Wladimir
authors.initials: W
authors.lastname: Ostheim-Dzerowycz
authors.forename: Georg
authors.initials: G
authors.lastname: Bongartz
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D001783:Blood Flow Velocity; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007269:Injections, Intra-Arterial; D035002:Lower Extremity / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000175:diagnosis*; D019047:Phantoms, Imaging; D011446:Prospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA