title: Multi-parametric MRI findings of granulomatous prostatitis developing after intravesical bacillus calmette-guérin therapy.
abstract: To evaluate the multi-parametric MRI (mpMRI) findings in patients with biopsy-proven granulomatous prostatitis and prior Bacillus Calmette-Guérin (BCG) exposure.
  
  
  
  MRI was performed in six patients with pathologically proven granulomatous prostatitis and a prior history of bladder cancer treated with intravesical BCG therapy. Multi-parametric prostate MRI images were recorded on a GE 750W or Philips Achieva 3.0 Tesla MRI scanner with high-resolution, small-field-of-view imaging consisting of axial T2, axial T1, coronal T2, sagittal T2, axial multiple b-value diffusion (multiple values up to 1200 or 1400), and dynamic contrast-enhanced 3D axial T1 with fat suppression sequence.
  
  
  
  Two different patterns of MR findings were observed. Five of the six patients had a low mean ADC value <1000 (decreased signal on ADC map images) and isointense signal on high-b-value imaging (b = 1200 or 1400), consistent with nonspecific granulomatous prostatitis. The other pattern seen in one of the six patients was decreased signal on the ADC map images with increased signal on the high-b-value sequence, revealing true restricted diffusion indistinguishable from aggressive prostate cancer. This patient had biopsy-confirmed acute BCG prostatitis.
  
  
  
  Our study suggests that patients with known BCG exposure and PI-RADS v2 scores ≤3, showing similar mpMRI findings as demonstrated, may not require prostate biopsy.
authors.affiliation: New York Institute of Technology College of Osteopathic Medicine, 1371 King James Ct., Oak Park, CA, 91377, USA. jgottlie@nyit.edu.
authors.forename: Josh
authors.identifier: 0000-0002-4970-4637
authors.initials: J
authors.lastname: Gottlieb
authors.affiliation: Rolling Oaks Radiology, 415 Rolling Oaks Dr #125, Thousand Oaks, CA, 91361, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Princenthal
authors.affiliation: Rolling Oaks Radiology, 415 Rolling Oaks Dr #125, Thousand Oaks, CA, 91361, USA.
authors.forename: Martin I
authors.initials: MI
authors.lastname: Cohen
mesh_terms: D000368:Aged; D001500:BCG Vaccine / Q000009:adverse effects*; D001706:Biopsy; D003287:Contrast Media; D006801:Humans; D007167:Immunotherapy / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011472:Prostatitis / Q000139:chemically induced* / Q000000981:diagnostic imaging*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy*
chemical_list: D001500:BCG Vaccine; D003287:Contrast Media
keywords: BCG; Granulomatous prostatitis; MRI; Prostate; Prostate cancer