Clinical utility of endorectal MRI‐guided prostate biopsy: Preliminary experience

Abstract

Purpose To investigate the potential clinical utility of endorectal MRI-guided biopsy in patients with known or suspected prostate cancer. Methods We prospectively recruited 24 men with known or suspected prostate cancer in whom MRI-guided biopsy was clinically requested after multiparametric endorectal MRI showed one or more appropriate targets. One to six 18-gauge biopsy cores were obtained from each patient. Transrectal ultrasound guided biopsy results and post MRI-guided biopsy complications were also recorded. Results MRI-guided biopsy was positive in 5 of 7 patients with suspected prostate cancer (including 2 of 4 with prior negative ultrasound-guided biopsies), in 8 of 12 with known untreated prostate cancer (including 5 where MRI-guided biopsy demonstrated a higher Gleason score than ultrasound guided biopsy results), and in 3 of 5 with treated cancer. MRI-guided biopsies had a significantly higher maximum percentage of cancer in positive cores when compared to ultrasound guided biopsy (mean of 37 ± 8% versus 13 ± 4%; p = 0.01). No serious post-biopsy complications occurred. Conclusion Our preliminary experience suggests endorectal MRI-guided biopsy may safely contribute to the management of patients with known or suspected prostate cancer by making a new diagnosis of malignancy, upgrading previously diagnosed disease, or diagnosing local recurrence.

Prostate cancer with a pseudocapsule at MR imaging: a marker of high grade and stage disease?

“…Tumor size was measured as the maximum axial diameter. Using an amalgam of previously described methodologies [3, 6, 7], prostate cancer was defined as focal low T2 signal intensity with an ellipsoid or crescentic subcapsular morphology in the peripheral zone or infiltrative “erased charcoal” non-encapsulated appearance in the central gland accompanied by focal reduction in apparent diffusion coefficient or accompanied by focal early intense enhancement or rapid washout at perfusion imaging. A pseudocapsule was defined as a visible rim of low T2 signal intensity around all or part of the tumor margin that was not abutting the true capsule of the prostate gland or the pseudocapsule of the central gland.…”

“…On T2-weighted imaging, prostate cancer is typically seen as focal, non-encapsulated, low signal intensity that has an ellipsoid or crescentic subcapsular shape in the peripheral zone or an infiltrative “erased charcoal” appearance in the central gland. Such foci are especially suspicious when accompanied by additional abnormalities on multiparametric imaging, such as restricted diffusion, early intense enhancement, rapid washout, or a malignant spectral signature [3, 4]. Peripheral zone and central gland cancers typically do not have a tumor capsule, and encapsulation is generally considered indicative of nodules derived from benign prostatic hyperplasia [4].…”

Direct MRI-guided biopsy of the prostate: use of post-biopsy needle track imaging to confirm targeting

“…Two attending radiologists (FVC and BRF) reviewed all images on a picture archiving and communication system workstation (Impax; Agfa, Mortsel, Belgium) and identified potential biopsy targets by consensus. Using an amalgam of published experience [4–6], biopsy targets were defined as foci of low T2 signal intensity with an ellipsoid or crescentic subcapsular morphology in the peripheral zone or infiltrative “erased charcoal” non-encapsulated appearance in the central gland accompanied by focal reduction in apparent diffusion coefficient or accompanied by focal early intense enhancement or rapid washout at perfusion imaging.…”

“…The development of robust multiparametric MRI for tumor visualization has led to the concept of targeted biopsy, in which biopsy samples are obtained only from the dominant disease site or sites seen at MRI [2, 3]. The hope is that MRI-guided biopsy, whether performed under direct guidance in the bore of the scanner or by fusion of MRI images to real-time transrectal ultrasound [4–6], will reduce the high false negative and tumor under-grading rates associated with the standard non-targeted approach [2, 3]. One question that arises during direct MRI-guided biopsy is how can we be assured that the sample is from the intended location?…”

Advances in imaging modalities in prostate cancer

“…The fusion biopsy was more likely to detect clinically significant PCa when compared with the 12-core modality (47.9 vs. 30.7%) and among the cancers missed by 12 core, 20.9% were clinically significant [10]. Several other groups recently reported on the utility of mpMRI in noninvasive detection of PCa [11][12][13].…”