Multiphase contrast-enhanced magnetic resonance imaging features of Bacillus Calmette-Guérin-induced granulomatous prostatitis in five patients.
OBJECTIVE
To evaluate the multiphase contrast-enhanced magnetic resonance (MR) imaging features of Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis (GP).


METHODS
Magnetic resonance images obtained from five patients with histopathologically proven BCG-induced GP were retrospectively analyzed for tumor location, size, signal intensity on T2-weighted images (T2WI) and diffusion-weighted images (DWI), apparent diffusion coefficient (ADC) value, and appearance on gadolinium-enhanced multiphase images. MR imaging findings were compared with histopathological findings.


RESULTS
Bacillus Calmette-Guérin-induced GP (size range, 9-40 mm; mean, 21.2 mm) were identified in the peripheral zone in all patients. The T2WI showed lower signal intensity compared with the normal peripheral zone. The DWIs demonstrated high signal intensity and low ADC values (range, 0.44-0.68 × 10(-3) mm(2)/sec; mean, 0.56 × 10(-3) mm(2)/sec), which corresponded to GP. Gadolinium-enhanced multiphase MR imaging performed in five patients showed early and prolonged ring enhancement in all cases of GP. Granulomatous tissues with central caseation necrosis were identified histologically, which corresponded to ring enhancement and a central low intensity area on gadolinium-enhanced MR imaging. The findings on T2WI, DWI, and gadolinium-enhanced images became gradually obscured with time.


CONCLUSIONS
Bacillus Calmette-Guérin-induced GP demonstrates early and prolonged ring enhancement on gadolinium-enhanced MR imaging which might be a key finding to differentiate it from prostate cancer.
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Hiroshi
H
Kawada
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan. ; Department of Radiology Services, Gifu University Hospital, Gifu 501-1194, Japan.
Masayuki
M
Kanematsu
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Satoshi
S
Goshima
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Hiroshi
H
Kondo
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Haruo
H
Watanabe
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Yoshifumi
Y
Noda
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Yukichi
Y
Tanahashi
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Nobuyuki
N
Kawai
Department of Radiology, Gifu University Hospital, Gifu 501-1194, Japan.
Hiroaki
H
Hoshi
D000368:Aged; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D007167:Immunotherapy / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009163:Mycobacterium bovis / Q000472:pathogenicity*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000175:diagnosis; D011472:Prostatitis / Q000175:diagnosis*; D012189:Retrospective Studies; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy
D005682:Gadolinium; D017430:Prostate-Specific Antigen
BCG; Granulomatous prostatitis; Multiphase contrast-enhanced MR imaging; Ring enhancement