title: Effect of Low-Osmolar Intravenous Contrast on Renal Length.
abstract: OBJECTIVE
  The purpose was to study the effect of low-osmolar nonionic contrast on renal length.
  
  
  METHODS
  This study included 56 patients (4-phase renal computed tomography [CT] and 4-phase CT urogram [CTU], 19 patients each; split-phase CTU, 18 patients). Three radiologists created the best off-axis plane and renal lengths measured on a postprocessing workstation. Two-way analysis of variance with Bonferroni corrections was performed along with single-sample t tests.
  
  
  RESULTS
  Four-phase renal CT and CTU average differences from unenhanced phases were 0.30/0.16 mm (corticomedullary), 0.88/1.33 mm (nephrographic), and 2.17/2.22 mm (delayed). The nephrographic and delayed phases were significantly different from their unenhanced phase (P < 0.01). Nonsignificant differences between the corticomedullary phase and the unenhanced phase were observed (P = 0.217, 4-phase renal CT; P = 0.232, 4-phase CTU). The split-phase CTU average difference in the enhanced phase was 1.36 mm (P < 0.001).
  
  
  CONCLUSIONS
  Renal length increases 1 to 2 mm with low-osmolar nonionic contrast.
authors.affiliation: From the *Department of Radiology, San Antonio Military Medical Center, Ft. Sam Houston, TX; †Department of Radiology, Uniformed Services University of the Health Sciences, Bethesda, MD; ‡Resource Management Division, Brooke Army Medical Center, Houston, TX; and §Department of Radiology, Stony Brook University Medical Center, Stony Brook, NY.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lisanti
authors.forename: Charles
authors.initials: C
authors.lastname: Hounshell
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Pate
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Reiter
authors.forename: Ryan B
authors.initials: RB
authors.lastname: Schwope
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D003287:Contrast Media; D005260:Female; D006801:Humans; D007479:Iopamidol; D007668:Kidney / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007479:Iopamidol