title: Renal and perirenal space involvement in acute pancreatitis: An MRI study.
abstract: OBJECTIVE
  To study the prevalence and characteristics of renal and perirenal space involvement and its relation to the severity of acute pancreatitis (AP) using MRI.
  
  
  METHODS
  115 patients with AP who underwent MRI with the clinical kidney function test were retrospectively analyzed in this study. MRI sequences included conventional and diffusion weighted imaging (DWI) sequences. The renal and perirenal space involvement in AP was noted on MRI. The renal apparent diffusion coefficient (ADC) on DWI was measured for each kidney. The severity of AP on MRI was graded using MR severity index (MRSI). The relationships among the renal and perirenal space involvement on MRI, the renal ADC, MRSI and the results of the kidney function test were analyzed.
  
  
  RESULTS
  In the 115 patients with AP, the renal and perirenal space abnormalities detected included renal parenchymal abnormalities (0.8%), abnormalities of the renal collecting system (2.6%), renal vascular abnormalities (1.7%), thickened renal fascia (99%), perirenal stranding (62%) and perirenal fluid collection (40%). The prevalence of perirenal space abnormalities was correlated with the severity of AP based on MRSI (P<0.05). The renal ADC values were lower in patients with abnormal kidney function than in those without kidney injury (P<0.05). The prevalence of kidney function abnormalities was 9.4%, 32% and 100% in mild, moderate, and severe AP cases, respectively (P=0.00).
  
  
  CONCLUSIONS
  Perirenal space involvement is much more than renal parenchymal involvement in AP. The prevalence of perirenal space involvement in AP on MRI has a positive correlation with the severity of AP according to MRSI.
authors.affiliation: Sichuan Key Laboratory of Medical Imaging, Department of Radiology, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, China. lixinghui1005@126.com
authors.forename: Xing Hui
authors.initials: XH
authors.lastname: Li
authors.forename: Xiao Ming
authors.initials: XM
authors.lastname: Zhang
authors.forename: Yi Fan
authors.initials: YF
authors.lastname: Ji
authors.forename: Zong Lin
authors.initials: ZL
authors.lastname: Jing
authors.forename: Xiao Hua
authors.initials: XH
authors.lastname: Huang
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Zhao Hua
authors.initials: ZH
authors.lastname: Zhai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000150:complications* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019283:Pancreatitis, Acute Necrotizing / Q000150:complications* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult