Paul Arangua

Multi-parametric MRI findings of transitional zone prostate cancers: correlation with 3-dimensional transperineal mapping biopsy

Purpose A preliminary project to correlate MR findings with mapping prostate biopsy to help differentiate malignant transitional zone lesions form benign prostatic hyperplasia (BPH) nodules. Materials and Methods Institutional IRB approved retrospective study with 14 patients suspected of having prostate cancer who underwent both prostate 3T MRI using endorectal coil and 3D transperineal mapping prostate biopsy. MR exams were independently reviewed by two abdominal radiologists blinded to pathology with disagreement resolved by consensus. An MRI lesion was defined as having hypointense T2 signal subjectively without corresponding T1 high signal intensity and low signal on ADC maps in the central gland. Mapping biopsy consisted of systematic transperineal US guided biopsy with 55–108 cores per patient. Results Twenty-nine lesions were detected on MRI. Of these, 13 correlated with Gleason 6 or higher biopsy samples. 16 were biopsy negative. Among the various MRI characteristics assessed, lack of T2 hypointense rim demonstrated the highest specificity (93%) and positive predictive value (89%). Highest sensitivity (85%) and negative predictive value (78%) were seen with ill-defined nodules. When suspicious MR characteristics were combined, the specificity and PPV rose to 100% while sensitivity decreased to 45% and NPV decreased to 73%. Conclusions Preliminary study indicates MR findings which can help differentiate a BPH nodule from transitional zone prostate cancers which could help direct biopsy in the large and growing number of people suspected of having prostate cancer. Further work will be needed for validation.

The 3DBiopsy Prostate Biopsy System: Preclinical Investigation of a Needle, Actuator, and Specimen Collection Device Allowing Sampling of Individualized Prostate Lengths Between 20 and 60 mm

OBJECTIVE To increase the likelihood of detecting anterior cancers within the prostate and provide a specimen that spans the length of the gland. Newly designed 17- and 15-gauge (G) biopsy needles, a variable actuator, and an integrated pathology system intended for the longer cores were developed and tested for this purpose. MATERIALS AND METHODS Testing was performed comparing 2 common cannula tip grinds, a Vet-point (sharp tip) and a Menghini-point (atraumatic tip), and were tested against 18-G Bard Monopty in porcine kidney. A variable actuator was developed to fire the needle 20-60 mm and tested in cadaver prostates. RESULTS The aggregate firings for 3 different shot lengths comparing the Vet- with the Menghini-tip cannulas demonstrated 91% vs 85.2% fill (length of specimen/length of core bed, P = .007). A 15-G trocar needle with the Vet-tip cannula also had the best performance, with an aggregate standard deviation of 6.4% across 3 firing ranges and a minimum to maximum specimen length of 81%-105% of potential fill. Cadaver testing with the Vet-tip needles in the actuator for the transrectal (17-G) and transperineal (15-G) biopsies demonstrated mean fills of 93.3% and 76.5%, respectively. The new transrectal ultrasound needle obtained a 2-fold increase in specimen length over the standard Bard device (P <.001). CONCLUSION Longer and consistent cores were obtained using the new biopsy needles. Combined with an adjustable actuator, the physician can obtain specimens that include peripheral and anterior zone tissue in 1 core. Determination of cancer location on the longer specimens could enhance focal therapy planning.

3D Biopsy: A New Method to Diagnose Prostate Cancer

Transperineal mapping biopsy (TPMB) is a substantial improvement over transrectal ultrasound guided biopsy (TRUS) in accurate grading and lesion identification, yet lacks standardization and in its current form utilizes antiquated technology. Theoretical models demonstrate that sampling the prostate at 5 mm intervals with a 15-gauge biopsy needle would detect 2.5 mm lesions with excellent accuracy. In practice, this approach is problematic due to deflection of biopsy needles during travel into the gland, movement of the gland during respiration, and technological constraints requiring multiple sampling attempts along the same needle path to cover the full length of the prostate. To help solve these problems, a software program was created to provide a real-time 3D image of the prostate generated from intraoperative axial (transverse) image capture. This software both generates a biopsy plan designed to provide complete coverage of the gland and subsequently monitors sampling in real-time to ensure adequate coverage is obtained. Moreover, if a patient is found to have cancer amenable to targeted focal therapy, the 3D map can be utilized in the OR to locate the sites to be ablated. What follows is a detailed description of how the software works and what additional changes are necessary to overcome the current challenges facing TPMB. The increased sampling accuracy that can be obtained with 3D mapping biopsy (MB) is necessary for proper risk stratification allowing improved selection of surveillance candidates.