title: Effect of intravenous gadolinium-DTPA on diffusion-weighted magnetic resonance images for evaluation of focal hepatic lesions.
abstract: OBJECTIVE
  Diffusion-weighted imaging (DWI) is usually performed before administration of intravenous contrast agents. Repetition of DWI is occasionally necessary after contrast administration, but the effects of contrast material on DWI and apparent diffusion coefficient (ADC) values in the abdomen have not yet been fully examined. The purpose of this work is to assess whether administration of gadolinium-based contrast material significantly affects DWI and ADC values at the focal hepatic lesions.
  
  
  METHODS
  The results of DWI at 3.0 T (Signa VH3; GE Medical Systems, Milwaukee, WI) were examined in 20 patients (age range: 33-86 years, mean age = 68 years) who were evaluated by means of a hepatic protocol at our hospital. Among the 20 patients studied, a total of 57 lesions were detected. Diffusion-weighted imaging was obtained using single-shot echo planar imaging with a b value of 500 s/mm. Patients were injected with 0.1 mmol/kg gadopentetate dimeglumine. The signal-to-noise ratio (SNR) of the liver and the hepatic lesions was examined, and the contrast-to-noise ratio (CNR) of each lesion was evaluated. In addition, the ADC values calculated from the DWI were compared before and after administration of contrast agent. The statistical significance of differences between precontrast and postcontrast administration was determined by use of a paired t test.
  
  
  RESULTS
  The SNR and CNR of the DWI were not significantly different before and after administration of contrast agent. The ADC values tended to decrease after administration of contrast agent for each focal hepatic lesion and the liver, although they did not reach statistical significance.
  
  
  CONCLUSIONS
  There was no significant difference before and after administration of contrast agent in the SNR or CNR of DWI. This indicates the feasibility of postcontrast DWI as a substitute for an unsuccessful precontrast-enhanced study in clinical practice.
authors.affiliation: Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan, Republic of China.
authors.forename: Fang-Ying
authors.initials: FY
authors.lastname: Chiu
authors.forename: Jo-Chi
authors.initials: JC
authors.lastname: Jao
authors.forename: Chiao-Yun
authors.initials: CY
authors.lastname: Chen
authors.forename: Gin-Chung
authors.initials: GC
authors.lastname: Liu
authors.forename: Twei-Shiun
authors.initials: TS
authors.lastname: Jaw
authors.forename: Yen-Yu
authors.initials: YY
authors.lastname: Chiou
authors.forename: Feng-O
authors.initials: FO
authors.lastname: Hsu
authors.forename: Jui-Sheng
authors.initials: JS
authors.lastname: Hsu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000175:diagnosis / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000473:pathology; D018281:Cholangiocarcinoma / Q000175:diagnosis / Q000473:pathology; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000556:secondary; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D017352:Echo-Planar Imaging; D005260:Female; D019786:Gadolinium DTPA; D006391:Hemangioma / Q000175:diagnosis / Q000473:pathology; D019694:Hepatitis B, Chronic / Q000150:complications / Q000473:pathology; D019698:Hepatitis C, Chronic / Q000150:complications / Q000473:pathology; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D008099:Liver / Q000473:pathology*; D008100:Liver Abscess / Q000175:diagnosis* / Q000473:pathology; D008103:Liver Cirrhosis / Q000175:diagnosis* / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA