title: Effect of intravenous extracellular gadolinium based contrast medium on renal diffusion weighted images.
abstract: OBJECTIVE
  The aim of this study was to compare precontrast and postcontrast renal diffusion-weighted images for signal intensity (SI), apparent diffusion coefficient (ADC), and lesion conspicuity.
  
  
  METHODS
  In 62 patients (mean age, 54 ± 29; 29 men, 33 women) precontrast and postcontrast (0.1 mmol/kg of extracellular gadolinium-based contrast medium; mean, 3.3 ± 0.9 minutes], diffusion-weighted images at b values of 50 and 400 s/mm² were compared (3 T). The SI, signal-to-noise ratio, and ADC of the renal cortex, medulla, and lesions were measured. Lesion contrast-to-noise ratios (against the medulla and cortex) were calculated.
  
  
  RESULTS
  Postcontrast medullary SI decreased by 50% and cortical SI decreased by 33% and 39% on images at b = 50 s/mm² and b = 400 s/mm², respectively (P < .0001). The SI and signal-to-noise ratio of lesions did not change significantly after contrast, but lesion-medullary contrast-to-noise ratio was increased by 50% at both b = 50 s/mm² and b = 400 s/mm² (P < .005 and P = .0005, respectively) following contrast. Qualitative postcontrast lesion conspicuity was improved, with average scores of 2.8 ± 0.9 for all lesions (κ = 0.7 ± 0.08) and 3.2 ± 0.9 for solid lesions (κ = 0.82 ± 0.1). The ADC of renal cortex decreased (P = .03), but the ADC of renal medulla or renal lesions did not significantly change.
  
  
  CONCLUSIONS
  Postcontrast diffusion-weighted imaging causes a significant decrease in renal parenchymal signal without a significant change in lesion signal, resulting in increased lesion conspicuity.
authors.affiliation: Department of Radiological Sciences, University of California, Irvine, UCI Medical Center, Orange, 92868-3298, USA. fsaremi@uci.edu
authors.forename: Farhood
authors.initials: F
authors.lastname: Saremi
authors.forename: Sepideh
authors.initials: S
authors.lastname: Sefidbakht
authors.forename: Lisa
authors.initials: L
authors.lastname: Quane
authors.forename: Jed
authors.initials: J
authors.lastname: Santa Maria
authors.forename: Armen
authors.initials: A
authors.lastname: Khararjian
authors.forename: Mehdi
authors.initials: M
authors.lastname: Jalili
mesh_terms: D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007275:Injections, Intravenous; D007668:Kidney / Q000473:pathology*; D007672:Kidney Cortex / Q000473:pathology; D007674:Kidney Diseases / Q000175:diagnosis; D007679:Kidney Medulla / Q000473:pathology; D007680:Kidney Neoplasms / Q000175:diagnosis; D008099:Liver / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013154:Spleen / Q000473:pathology
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA