title: Low injection rate for 3D moving-table bolus-chase MR angiography: initial experience with 3-T imaging to allay venous contamination in the calf.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the potential for improving the image quality of 3D bolus-chase peripheral MR angiography by injecting contrast medium at a slow rate.
  
  
  METHODS
  Using similar imaging parameters in all cases, we performed bolus-chase MR angiography of the abdominal and lower limb arteries of 80 patients. The injection protocol for 40 patients had three parts: 20 mL of gadopentetate dimeglumine at 2 mL/s, 8 mL of gadopentetate dimeglumine at 1 mL/s, and 20 mL of saline solution at 1 mL/s. For the other 40 patients, the injection protocol was 20 mL of gadopentetate dimeglumine at 1.2 mL/s, 8 mL of gadopentetate dimeglumine at 0.7 mL/s, and 20 mL of saline solution at 0.7 mL/s. Using independent Student's t tests between groups, we compared signal-to-noise and contrast-to-noise ratios in the abdomen and pelvis, the thigh, and the calf. Arterial visibility and venous contamination on 3D images of the calf were graded and compared.
  
  
  RESULTS
  The lower injection rate increased arterial visibility (p < 0.001), reduced venous contamination in the calf (p < 0.001), and increased the contrast-to-noise ratio in the calf (p < 0.001). At the upper levels, signal-to-noise and contrast-to-noise ratios did not differ between the two groups.
  
  
  CONCLUSIONS
  At 3-T MRI, a lower injection rate may alleviate venous contamination and increase arterial visibility in the calf while signal-to-noise and contrast-to-noise ratios at higher levels are maintained.
authors.affiliation: Department of Radiology, Beijing Institute of Heart, Lung, and Blood Vessel Diseases and Beijing Anzhen Hospital, Capital Medical University, Beijing, China. kai@jhmi.edu
authors.forename: Kai
authors.initials: K
authors.lastname: Lin
authors.forename: Zhao-Qi
authors.initials: ZQ
authors.lastname: Zhang
authors.forename: Jun-Yan
authors.initials: JY
authors.lastname: Sun
authors.forename: Zhan-Ming
authors.initials: ZM
authors.lastname: Fan
authors.forename: Biao
authors.initials: B
authors.lastname: Lu
mesh_terms: D000328:Adult; D000368:Aged; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000517:prevention & control; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007275:Injections, Intravenous; D007866:Leg / Q000098:blood supply / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000175:diagnosis*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014680:Veins / Q000473:pathology
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA