When performed with computerized magnetic resonance imaging-transrectal ultrasound image registration, targeted biopsy alone improved cancer detection over random biopsies, decreased the detection rate of microfocal cancer and increased the detection rate of cancer with a Gleason score of greater than 6.

The authors report the diffusion and contrast-enhanced MRI appearance of five cases of granulomatous prostatitis (GP), non-specific (two cases) and infectious post-Bacillus Calmette-Guerin (BCG) therapy (three cases, with a tubercular abscess in two of them). All patients had raising PSA levels and abnormal DRE. History of BCG therapy or acute prostatitis was present in four patients. Multiparametric MRI (T2W-MRI, DW-MRI and DCE-MRI) was performed before biopsies. Diagnosis was confirmed by TRUS-guided biopsies in four cases and by transurethral resection in one case. MRI showed a tumor-like appearance in three cases, an abscess-like appearance in one case and a combined tumor/abscess-like appearance in one case. Extraprostatic fat was infiltrated in three patients, simulating T3a disease. Histologically, caseous necrosis was found when MRI showed abcedation. Demonstration of occult tubercular abscesses in post-BCG GP may have therapeutic implications and MRI is useful prior to surgical or interventional drainage of large caseous abscesses.

The role of magnetic resonance imaging (MRI) in prostate cancer evaluation is controversial and likely underestimated. Technological advances over the past 5 years have demonstrated that multiparametric MRI, including diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI, can evaluate the actual tumor burden of a newly diagnosed prostate cancer more accurately than sextant biopsy protocols. Tumor risk, defined by the D'Amico criteria, hence can be re-evaluated by multiparametric MRI. As a result, there is increasing evidence that MRI before repeat or even initial biopsy can accurately select patients who require immediate biopsies and those in whom biopsy could be deferred. Also, a relationship between apparent diffusion coefficient (ADC), calculated from DWI, and Gleason score was found. Thus, MRI before biopsy helps to detect high-grade tumors to target biopsies within areas of low ADC values. To achieve good targeting accuracy, transrectal ultrasound (TRUS)-MRI image registration is necessary. Three-dimensional deformable registration is sufficiently accurate to match TRUS and MRI volumes with a topographic precision of 1 mm. Real-time MRI-guided biopsy is another technique under evaluation. Both approaches will allow for increasing acceptance of focal therapies, should these techniques be validated in the future.

In epididymo-orchitis, a sonogram shows a non-homogenous and hypertrophied epididymis and testis, with increased vascularisation seen on a Doppler sonogram. Abscesses must be investigated using sonography so that a necrotic tumour is not misdiagnosed. In prostatitis, sonography is indicated to investigate urine retention and where treatment has failed (to look for a blockage, an abscess, or pyelonephritis). Endorectal sonography is the best imaging modality for analysing the parenchyma, but otherwise has limited value. Chronic prostatitis is the main differential diagnosis from prostate cancer; the two may be distinguished using diffusion MRI. In cases of cystitis, imaging is indicated when a patient has recurrent cystitis (to investigate what the causative factors might be), or an infection with a less common bacterium (to look for calcifications, emphysema, any involvement of the upper urinary tract), and in cases of cystitis with pseudotumour.