title: Selection for biopsy of kidney transplant patients by diffusion-weighted MRI.
abstract: OBJECTIVE
  To assess retrospectively whether diffusion-weighted magnetic resonance imaging (DW-MRI) allows physicians to determine the severity of histopathologic findings in biopsies of renal allograft patients with deteriorating renal function.
  
  
  METHODS
  Forty consecutive kidney transplant patients underwent DW-MRI and biopsy. Patients were assigned to one group with severe and to another group with normal or mild histopathologic findings. These two groups were compared based on a qualitative DW-MRI assessment (homo-/heterogeneity) and the combination of qualitative and quantitative DW-MRI parameters (ADC, and intravoxel incoherent motion, IVIM, parameters: D, f, D*). Sensitivity, specificity, and accuracy were determined for each parameter.
  
  
  RESULTS
  Biopsy findings were severe in 25 patients and normal or mild in 15 patients. Qualitative DW-MRI led to a sensitivity of 44.0% and a specificity of 93.3%. Combined qualitative and quantitative DW-MRI led to an accuracy of 80% for both the minimal ADC (ADCmin) and the minimal perfusion fraction (fmin) with a sensitivity of 84.0% and 92.0% and a specificity of 73.3% and 60.0%, respectively.
  
  
  CONCLUSIONS
  Combined qualitative and quantitative DW-MRI might allow physicians to determine the severity of histopathologic findings in biopsies of a high number of kidney transplant patients.
  
  
  CONCLUSIONS
  • Qualitative DW-MRI is highly specific when predicting the severity of kidney transplant biopsy. • Allografts appearing heterogeneous on ADC are associated with severe histopathologic findings. • Combining qualitative and quantitative DW-MRI parameters improves the classification's sensitivity and accuracy. • Kidney transplant biopsies might be spared by combining qualitative and quantitative DW-MRI.
authors.affiliation: Department of Radiology, Neuroradiology, and Nuclear Medicine, Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital, Bern University Hospital, University of Bern, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Steiger
authors.affiliation: Department of Radiology, Neuroradiology, and Nuclear Medicine, Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital, Bern University Hospital, University of Bern, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Barbieri
authors.affiliation: Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
authors.forename: Anja
authors.initials: A
authors.lastname: Kruse
authors.affiliation: Department of Radiology, Neuroradiology, and Nuclear Medicine, Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital, Bern University Hospital, University of Bern, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Ith
authors.affiliation: Department of Radiology, Neuroradiology, and Nuclear Medicine, Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital, Bern University Hospital, University of Bern, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland. Harriet.thoeny@insel.ch.
authors.forename: Harriet C
authors.initials: HC
authors.lastname: Thoeny
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009038:Motion; D010477:Perfusion; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Anatomy & histology; Biopsy; Diffusion-weighted magnetic resonance imaging; Echo-planar imaging; Renal transplant