title: A comparison of the efficacy and safety of iopamidol-370 and iodixanol-320 in patients undergoing multidetector-row computed tomography.
abstract: OBJECTIVE
  To prospectively compare the effects on heart rate (HR) and contrast enhancement efficacy of iopamidol-370 and iodixanol-320 in contrast-enhanced, multidetector-row computed tomography (CE-MDCT).
  
  
  METHODS
  IMPACT is a multicenter, double-blind study involving 166 patients undergoing CE-MDCT of the liver (n = 121) or peripheral arteries (n = 45) randomized to receive equi-iodine doses (40 gI) of iopamidol-370 or iodixanol-320 intravenous at 4 mL/s. CE-MDCT was performed using 16-MDCT scanners according to predefined imaging protocols. HR was measured with the patient in the supine position before and continuously for 5 minutes after contrast medium administration. Mean and peak increases in HR and the proportion of subjects with predefined HR increases (>5 to <10, 10 to <15, 15 to <20, >20 bpm) were compared in the 2 populations. Liver images were assessed by 2 independent, blinded readers for contrast enhancement [Hounsfield unit (HU)], using predefined regions-of-interest during the arterial and portal-venous phase of enhancement.
  
  
  RESULTS
  Effects on HR: Eighty-four subjects received iopamidol-370 whereas 82 received iodixanol-320. Mean age, gender distribution, weight, total iodine dose, dose/body weight, concomitant medications and use of beta-blockers were comparable in the 2 groups. Mean baseline HR was similar in the 2 groups (iopamidol-370: 72.3 +/- 12.5 bpm; iodixanol-320: 74.5 +/- 11.9 bpm). Mean changes from baseline to peak postdose were similar in the 2 groups (8.0 +/- 9.3 bpm after iopamidol-370 and 8.4 +/- 14.7 after iodixanol-320, P = 0.72). The proportion of subjects in each group having increases of <5, >5 to <10, 10 to <15, 15 to <20, or >20 bpm was comparable (P = 0.87). Two subjects experienced postcontrast tachycardia (HR increase >70 bpm, peak HR of 146 and 164 bpm), both in the iodixanol-320 group (2.4%). Contrast Enhancement: Of the 121 patients undergoing liver CT, 60 received iopamidol-370 whereas 61 received iodixanol-320. Mean age, gender distribution, weight, total iodine dose, and dose/body weight were comparable in the 2 groups. Iopamidol-370 provided significantly higher HU values in abdominal aorta during the arterial phase of enhancement for both readers [R1: 301.3 +/- 80.2 vs. 273.6 +/- 65.9 HU, 95% confidence interval (6.1-56.8), P = 0.02; R2: 302.0 +/- 73.6 vs. 275.1 +/- 62.9 HU, 95% confidence interval (2.3-51.3), P = 0.03]. No significant difference was observed between the 2 contrast medium during the portal venous phase of enhancement.
  
  
  CONCLUSIONS
  When the same injection rate and iodine dose is used, the effects on HR of bolus intravenous injections of iopamidol-370 and iodixanol-320 were similar. Iopamidol-370 provides significantly greater enhancement during the arterial phase and similar enhancement during the portal venous phase compared with iodixanol-320.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA. dsahani@partners.org
authors.forename: Dushyant V
authors.initials: DV
authors.lastname: Sahani
authors.forename: Gilles
authors.initials: G
authors.lastname: Soulez
authors.forename: Ke-Min
authors.initials: KM
authors.lastname: Chen
authors.forename: Luigi
authors.initials: L
authors.lastname: Lepanto
authors.forename: Jian-Rong
authors.initials: JR
authors.lastname: Xu
authors.forename: Rendon C
authors.initials: RC
authors.lastname: Nelson
authors.forename: Luigi
authors.initials: L
authors.lastname: Grazioli
authors.forename: Angelo
authors.initials: A
authors.lastname: Vanzulli
authors.forename: Jay P
authors.initials: JP
authors.lastname: Heiken
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000187:drug effects; D003287:Contrast Media / Q000008:administration & dosage* / Q000633:toxicity; D004311:Double-Blind Method; D064420:Drug-Related Side Effects and Adverse Reactions; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage* / Q000633:toxicity; D007668:Kidney / Q000000981:diagnostic imaging / Q000187:drug effects; D007674:Kidney Diseases / Q000000981:diagnostic imaging; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D011446:Prospective Studies; D011856:Radiographic Image Enhancement; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods; D014283:Triiodobenzoic Acids / Q000008:administration & dosage* / Q000633:toxicity
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol; D007479:Iopamidol