title: Prospective evaluation of diffusion-weighted MRI of the bladder as a biomarker for prediction of bladder cancer aggressiveness.
abstract: OBJECTIVE
  To prospectively test the utility of diffusion-weighted magnetic resonance imaging (DW-MRI) for bladder cancer (BCA) staging and grading.
  
  
  METHODS
  We prospectively enrolled 51 consecutive patients (median age = 64 y, range: 30-90y) with suspected BCA with or without gross hematuria who received 3-T DW-MRI before transurethral resection of the bladder. Parametric apparent diffusion coefficient (ADC) maps were automatically calculated from DW-MRI. ADC values (given in × 10(-3)mm(2)/s) of bladder lesions were independently measured by 2 radiologists blinded to histopathology. Comparisons of ADC values with histopathologic features were performed using unpaired t tests. Diagnostic performance was calculated by means of receiver operating characteristics (ROC) statistics.
  
  
  RESULTS
  We excluded 8 patients: 1 presenting with metastatic melanoma to the bladder, 1 who had an incomplete examination, and 6 without BCA. In the 43 remaining patients (median age = 68 y, range: 41-85 y), the ADC values were lower in high-grade (n = 19, ADC = 0.787) compared with low-grade (n = 24, ADC = 1.233) tumors (P<0.0001) and in muscle-invasive tumors (n = 10, ADC = 0.759) compared with non-muscle-invasive tumors (n = 33, ADC = 1.120, P = 0.0004). The area under the ROC curve was 0.884 for prediction of muscle invasion and 0.906 for prediction of high grade by using ADC values. Rule-in ADC criteria for high-grade lesions and rule-out ADC criteria for muscle invasion were identified by ROC analysis.
  
  
  CONCLUSIONS
  ADC measurements obtained by DW-MRI are a promising imaging biomarker for prediction of BCA stage and grade providing high sensitivity and specificity. Further studies are necessary to establish the value of this test in guiding decision making in clinical practice.
authors: Department of Urology, Medical University of Vienna, Vienna, Austria.
authors: Sabina
authors: S
authors: Sevcenco
authors: Department of Biomedical Imaging and Image-Guided Biopsy, Medical University of Vienna, Vienna, Austria; Department of Radiology, Hospital Sankt-Poelten, Sankt-Poelten, Austria.
authors: Lothar
authors: L
authors: Ponhold
authors: Department of Biomedical Imaging and Image-Guided Biopsy, Medical University of Vienna, Vienna, Austria; Department of Radiology, Hospital Sankt-Poelten, Sankt-Poelten, Austria.
authors: Gertraud
authors: G
authors: Heinz-Peer
authors: Department of Urology, Medical University of Vienna, Vienna, Austria.
authors: Harun
authors: H
authors: Fajkovic
authors: Department of Pathology, Medical University of Vienna, Vienna, Austria.
authors: Andrea
authors: A
authors: Haitel
authors: Department of Pathology, Medical University of Vienna, Vienna, Austria.
authors: Martin
authors: M
authors: Susani
authors: Department of Urology, Medical University of Vienna, Vienna, Austria.
authors: Shahrokh F
authors: SF
authors: Shariat
authors: Department of Urology, Medical University of Vienna, Vienna, Austria.
authors: Tibor
authors: T
authors: Szarvas
authors: Department of Biomedical Imaging and Image-Guided Biopsy, Medical University of Vienna, Vienna, Austria. Electronic address: pascal.baltzer@meduniwien.ac.at.
authors: Pascal A T
authors: PA
authors: Baltzer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor
keywords: Biomarker; Bladder cancer; Diffusion-weighted imaging; Muscle invasiveness; Sensitivity and specificity; Staging