title: Contrast-enhanced magnetic resonance angiography of the lower extremities: standard-dose vs. high-dose gadodiamide injection.
abstract: OBJECTIVE
  To compare the efficacy and safety of two different doses (0.1 and 0.3 mmol/kg of body weight [BW]) of gadodiamide for contrast-enhanced magnetic resonance angiography (ce-MRA) of the lower extremities with intraarterial digital subtraction angiography (IA-DSA).
  
  
  METHODS
  A total of 30 patients with peripheral arterial occlusive disease underwent IA-DSA and ce-MRA from the aortic bifurcation down to the ankle. Patients were randomized to receive a total dose of 0.1 or 0.3 mmol/kg of BW gadodiamide (Omniscan, Amersham Buchler), administered intravenously as a series of three automatic bolus injections. Ce-MRA was performed with a 1.5-T system using a body phased-array coil, centered stepwise over the calf, thigh, and pelvic region. A fast T1-weighted, three-dimensional gradient-echo sequence was obtained before and after injection of the allocated dose. IA-DSA was performed using the Seldinger technique and a femoral approach. The vessels under investigation were divided into 31 segments, and ce-MRA and IA-DSA image sets were evaluated in a double-blind fashion for the presence of stenosis, presence of collateral vessels, vessel delineation, and overall image quality. Both dose groups were compared with regard to contrast index (CI) and signal- and contrast-to-noise ratios (SNR, CNR). The occurrence of adverse events or side effects was also documented. Sensitivity, specificity, and accuracy were calculated in relation to the results of stenosis grading.
  
  
  RESULTS
  A total of 26 patients were entered in the efficacy evaluation, while all 30 patients were included in the safety assessment. The sensitivity, specificity, and accuracy for the 0.1 and 0.3 mmol/kg dose groups were 78.8%/93.0%/88.9% vs. 60.2.%/91.5%/83.2%, respectively. The detection of collaterals was similar to IA-DSA for the 0.3 mmol/kg dose group (30.2% vs. 27.4%), but was lower in the 0.1 mmol/kg dose group (27.3% vs. 12.3%). The high-dose gadodiamide injection proved to be superior to the 0.1 mmol/kg dose group with regard to vessel delineation and overall image quality (P = 0.007 and P = 0.002, respectively). The difference between the two dose groups regarding CI, SNR, and CNR was significant (P = 0.0001), in favor of the 0.3 mmol/kg dose group. No adverse events were observed in any of the patients.
  
  
  CONCLUSIONS
  Ce-MRA with gadodiamide is safe and efficacious. Comparison of two different doses with IA-DSA as the standard of reference showed that the 0.3 mmol/kg dose is superior to the standard 0.1 mmol/kg dose with respect to contrast enhancement, vessel delineation, image quality, and detection of collaterals. However, the 0.1 mmol/kg dose was superior to the high dose in the grading of stenosis.
authors.affiliation: Institut für Röntgendiagnostik der Universität Würzburg, Würzburg, Germany. uekrause@aol.com
authors.forename: Ulrich
authors.initials: U
authors.lastname: Krause
authors.forename: Thomas
authors.initials: T
authors.lastname: Kroencke
authors.forename: Erika
authors.initials: E
authors.lastname: Spielhaupter
authors.forename: Matthias
authors.initials: M
authors.lastname: Taupitz
authors.forename: Werner
authors.initials: W
authors.lastname: Kenn
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.forename: Dietbert
authors.initials: D
authors.lastname: Hahn
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods*; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D003097:Collateral Circulation; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007275:Injections, Intravenous; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA