Phantom study of a novel stereotactic prostate biopsy system integrating preinterventional magnetic resonance imaging and live ultrasonography fusion.
ABSTRACT To determine the targeting error of a novel stereotactic prostate biopsy system that integrates preinterventional MRI with peri-interventional ultrasonography (US) for perineal navigated prostate biopsies.
We performed stereotactic biopsies on five prostate phantoms (one CIRS 053-MM and four CIRS 066). Phantom 053-MM incorporates three MRI- and transrectal ultrasonography (TRUS)-visible lesions, while lesions within phantom 066 are only detectable on MRI. In both phantoms, the 0.5 cc volume lesions are placed randomly. The phantoms were examined by 3T-MRI preinterventionally. Then three stereotactic biopsies from one lesion in phantom 053-MM and from all US-invisible lesions in the 066 phantoms were taken under live-fusion imaging guidance. During intervention, a mix of blue ink and gadobutrol was injected into each biopsy channel. Afterward, another 3T-MRI was obtained. These MRI images were then fused again with the intraoperative TRUS data. Thus, the targeting error (TE) between the planned and performed biopsy cores could be measured. In addition, the procedural targeting error (PTE) between the virtually planned biopsy trajectory and the manually registered three-dimensional needle position of every single biopsy core taken was calculated.
The overall TE of the 39 biopsy cores taken was 0.83 mm (standard deviation [SD]: 0.48 mm) with the highest TE in the sagittal plane (1.09 ± 0.54 mm), followed by the coronal (0.72 ± 0.43 mm) and axial (0.69 ± 0.34 mm) planes. The procedural TE, which is provided intraoperatively, was 0.26 mm on average (SD: 0.46 mm). Comparing PTE and TE, there was no statistically significant difference (P=0.39).
The TE of stereotactic biopsies using our novel perineal prostate biopsy system is below 1 mm and can be estimated in vivo by the automatically calculated procedural TE. Thus, stereotactic prostate biopsies guided by the combination of MRI and US allow effective and precise examination of MRI lesions.
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ABSTRACT: To determine whether improved prostate sampling by the extended biopsy scheme also improves the accuracy of the biopsy Gleason score (bGS). Because most prostate cancer cases are now detected at an early stage with a low prostate-specific antigen level, the bGS may be the most important factor in therapeutic decision-making. Sextant biopsy schemes had poor correlation with prostatectomy Gleason scores. Extended prostate biopsies have replaced the sextant scheme because of the former's greater cancer detection rate. We identified 426 patients whose biopsy and prostatectomy specimens were reviewed at our center. To minimize the effect of stage migration, all patients before 1997 were excluded. Of the 426 included patients, 221 men had undergone sextant biopsy and 205 men extended biopsy before prostatectomy. The rate of grading concordance and the effect of different variables on the concordance rate was determined. The overall accuracy of the extended and sextant schemes was 68% and 48% (P <0.001), respectively. Upgrading of the bGS was significantly less likely with the extended scheme (17% versus 41%, P <0.001). The sextant biopsy was more likely to be upgraded for a bGS of 6 or less (44% versus 25%, P <0.002) and a bGS of 7 (14% versus 3%, P <0.02). On multivariate analysis, the biopsy scheme was the only independent predictor of accurate Gleason scoring (P <0.001) and age, prostate-specific antigen level, digital rectal examination findings, prostate size, clinical stage, and number of positive cores were not. The use of an extended prostate biopsy scheme significantly improves the correlation between the bGS and prostatectomy Gleason score and reduces the risk of upgrading to a worse Gleason group at prostatectomy.Urology 02/2006; 67(2):379-83. · 2.42 Impact Factor
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ABSTRACT: Systematic transrectal ultrasound-guided biopsy (TRUSBx) is the gold standard for detecting prostate cancer. This systematic approach is characterized by low sensitivity (39-52%) and high specificity (81-82%). Magnetic resonance (MR)-guided biopsy techniques are becoming more and more available, but there is no current consensus on the optimal technique. This review presents an overview of MR-guided biopsy techniques for prostate cancer detection. Current literature was reviewed regarding MR-guided biopsy for prostate cancer detection. A literature search was performed using the commercially available MedLine online search engine. Combinations of the following search and Medical Subject Headings terms were applied to retrieve relevant articles: "magnetic resonance," "prostatic neoplasms," and "biopsy." Review articles and studies describing techniques other than MR-guided biopsy were excluded. Biopsy of the prostate is an essential procedure for determining optimal treatment. Systematic TRUSBx is the gold standard, but it fails to detect numerous tumors. Diagnostic MR imaging provides more accurate selection of regions in which tumors are suspected. Using these diagnostic images during an MR-directed biopsy procedure improves quality of the biopsy. In open MR scanners, the prebiopsy images often must be registered to the real-time biopsy images because open MR scanners do not provide optimal tissue contrast; thus, the patient must first be examined in a closed MR scanner and then biopsied in an open scanner. The advantage of open MR over closed MR is that the physician has easy patient access. With special equipment, prostate MR-guided biopsy is also possible in a closed system. Closed MR scanners can be used for the prebiopsy scan as well as for the biopsy procedure. The combination of a diagnostic MR examination and MR-guided biopsy is a promising tool and may be used in patients with previous negative TRUSBx.European Urology 07/2008; 54(3):517-27. · 10.48 Impact Factor
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ABSTRACT: To compare a new staging, three-dimensional prostate mapping biopsy (3D-PMB) method with traditional transrectal ultrasound (TRUS) biopsy and assess its possible impact on patient management. One hundred eighty patients with unilateral cancer on TRUS biopsy, who were considering conservative management, underwent restaging with 3D-PMB. The 3D-PMB was carried out transperineally using a brachytherapy grid under TRUS guidance. Biopsies were taken every 5 mm throughout the volume of the prostate, and labeling of the specimen coordinates allowed accurate reconstruction of the location and extent of a patient's cancer. 3D-PMB obtained a median of 50 cores (standard deviation, +/- 20.61). One hundred ten patients (61.1%) were positive bilaterally, and 41 patients (22.7%) had Gleason scores increased to 7 or higher. Thirty-six patients had negative results on 3D-PMB. Complications of 3D-PMB were self-limited and included 14 patients (7.7%) who required short-term indwelling catheter drainage and two patients with hematuria, one of whom required overnight bladder irrigation. 3D-PMB is a transperineal biopsy that can be safely used to accurately stage prostate cancer patients. At the present time, when patient management is increasingly based on the extent and characteristics of prostate cancer, 3D-PMB could have a profound effect on patient management.Journal of Clinical Oncology 09/2009; 27(26):4321-6. · 18.04 Impact Factor