Prostatic abscess and seminal vesicle abscess: MRI findings and quantitative analysis of apparent diffusion coefficient values

Purpose To investigate the conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) findings of prostatic abscess (PA) and seminal vesicle abscess (SVA), and to evaluate the qualitative and quantitative diagnostic value of apparent diffusion coefficient (ADC) for these conditions. Materials and methods Ten patients with PA and 2 patients with SVA who underwent MRI and DWI examinations (b = 0 and 1000 s/mm2) at our institution were enrolled in this study. The diagnoses of all the patients were pathologically and clinically proved. Their conventional MRI and DWI images as well as ADC values were analyzed. The ADC values between PA and surrounding prostate tissues were compared using t test. Statistical significance was inferred at P < 0.05. Results Six patients were revealed with multiple foci. The other 6 showed singular lesion, including the 2 with SVA. A total of 23 focal abscesses were demonstrated with iso-low T1WI signal as well as hyperintense T2WI and DWI signals. Four patients with PA presented air within the lesions by both T1WI and T2WI. The mean ADCs of PA, (0.618 ± 0.192) × 10−3 mm2 s−1, were significantly lower than that of surrounding prostate tissues, (1.417 ± 0.147) × 10−3 mm2 s−1 (P = 0.000). Conclusion PA and SVA can be characteristically demonstrated by MRI, and the lesions show especially restricted diffusion by DWI with low ADC values. These demonstrations facilitate their qualitative and quantitative diagnosis.