Comparison of endorectal magnetic resonance imaging, guided prostate biopsy and digital rectal examination in the preoperative anatomical localization of prostate cancer

PURPOSE: We compared the accuracy of endorectal magnetic resonance imaging (erMRI), transrectal ultrasound (TRUS) guided biopsy and digital rectal examination (DRE) for detecting the location of cancer in the prostate gland and seminal vesicles. MATERIALS AND METHODS: This is a retrospective study of 106 consecutive patients with prostate cancer who were referred for erMRI before radical prostatectomy. Step-section pathological data and erMRI were available in 90 patients, DRE data were available on 86 and individually labeled sextant core biopsies were available in 45. T1 and T2-weighted erMRI was interpreted by a single reader, who scored the likelihood of tumor on a 5-point scale in each seminal vesicle and in 12 locations in the prostate gland. MR spectroscopy data were not used for erMRI interpretation. One pathologist reviewed whole mount serial sections of radical prostatectomy specimens. The area under ROC curves was used to evaluate accuracy. RESULTS: The area under ROC curves for tumor localization was higher for erMRI than for DRE at the prostatic apex (0.72 vs 0.66), mid gland (0.80 vs 0.69) and base (0.83 vs 0.69). It was likewise higher for erMRI than for TRUS biopsy in the mid gland (0.75 vs 0.68) and base (0.81 vs 0.61) but not in the apex (0.67 vs 0.70). On mixed model analysis erMRI significantly increased the accuracy of prostate cancer localization by DRE or TRUS biopsy (each p <0.0001). CONCLUSIONS: For prostate cancer localization erMRI contributes significant incremental value to DRE or TRUS biopsy findings (each p <0.0001).     

Role of magnetic resonance imaging in defining a biopsy strategy for detection of prostate cancer

Prostate cancer is the second most common male cancer worldwide. It has a broad spectrum, from low‐risk, clinically indolent disease, to high‐risk aggressive cancer. This variety conveys certain diagnostic and management challenges. The use of prostate‐specific antigen as a screening test for prostate cancer is increasing the diagnosis of low‐grade, low‐volume disease. By targeting biopsies towards suspicious areas on multiparametric magnetic resonance imaging, we can accurately diagnose clinically significant prostate cancer, reducing identification of low‐risk, clinically indolent disease. This could avoid the radical treatment of histopathological cancer that might never have become clinically apparent. In the present review, we consider the use of multiparametric magnetic resonance imaging to inform the biopsy strategy. By identification of suspicious lesions on multiparametric magnetic resonance imaging, biopsy targets can be identified, and the sampling bias associated with blind standard transrectal prostate biopsy can be reduced. We consider the reliability of these radiological lesions for detection of clinically significant prostate cancer, and the methods of targeting them to ensure the radiological lesion is accurately sampled. Evidence suggests that targeted biopsy is efficient and accurate for diagnosis of clinically significant prostate cancer. By rationalizing diagnosis, and subsequently preventing overtreatment of clinically insignificant disease, magnetic resonance imaging‐informed prostate biopsy can provide a method for streamlining the diagnostic pathway in prostate cancer.     

Endorectal magnetic resonance imaging and spectroscopy for the detection of tumor foci in men with prior negative transrectal ultrasound prostate biopsy

Purpose

We determined the ability of combined endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) to detect prostate cancer foci prospectively in men with prior negative transrectal ultrasound (TRUS) prostate biopsy.

Materials and Methods

Endorectal MRI with spectroscopy was performed in 24 consecutive patients with 1 or more prior negative TRUS prostatic biopsies for persistently increased prostate specific antigen and/or abnormal digital rectal examination. All studies were interpreted by a dedicated radiologist who reported areas of interest in the peripheral zone as normal, equivocal or suspicious on MRI and MRSI separately. Equivocal and suspicious areas were then correlated with a 3-dimensional prostate model. All patients underwent a standard TRUS 10-core peripheral zone biopsy with up to 4 additional biopsies targeted at the equivocal or suspected sites.

Results

Prostate cancer was detected in 7 of 24 subjects (29.2%). Considering the equivocal category as test negative the sensitivity, specificity, positive and negative predictive values, and the accuracy of MRI, MRSI and combined MRI/MRSI for the detection of prostate cancer were 57.1%, 57.1% and 100.0%, 88.2%, 82.4% and 70.6%, 66.7%, 57.1% and 58.3%, 83.3%, 82.1% and 100%, and 79.2%, 75.0% and 79.2%, respectively. The site of positive biopsy correlated correctly in 50% and 28.6% of MRI and MRSI labeled suspicious cores, respectively.

Conclusions

MRI and MRSI have the potential to identify cancer foci and direct TRUS in patients with a previous negative TRUS biopsy. Further, larger studies are required to quantify the amount of benefit.     

Technique for a hybrid system of real‐time transrectal ultrasound with preoperative magnetic resonance imaging in the guidance of targeted prostate biopsy

Diagnostic magnetic resonance imaging (MRI) for prostate has achieved increasingly higher levels of accuracy. Because real‐time MR‐guided targeted biopsy is still a complicated and expensive procedure, there is considerable interest in a technique of MR/transrectal ultrasound (TRUS) hybridized image‐guided biopsy. However, because the 3‐D shapes of the prostate at the time of image‐acquisition at preoperative MRI are likely to be different from the intra‐operative TRUS images, the precise registration of each 3‐D volume data is critical. To reduce the potential errors in registration of TRUS with MRI, we introduce new procedural techniques in a rigid image fusion technique. First, preoperative MR images were obtained with a specifically‐made plastic outer‐frame, with exactly the same shape as the real TRUS probe, placed in the rectum, in order to simulate the deformation of the prostate caused by the absence or presence of a TRUS probe during the acquisition of MR or TRUS images. Second, instead of using a single plane of longitudinal image, we applied biplane TRUS images to be shown in parallel on a multiplanar display with corresponding reconstructed MRI, in order to register both horizontal and longitudinal images of the prostate simultaneously, thereby achieving improved 3‐D anatomical matching.     

MRI/US成像融合引导的经会阴前列腺穿刺活检的单中心研究

目的:评估磁共振/超声(MRI/US)成像融合引导的经会阴前列腺穿刺活检对前列腺癌诊断的价值。方法:回顾性分析2014年9月~2016年3月我院行MRI/US成像融合引导的经会阴前列腺穿刺活检的121例患者资料,每例均行12针系统性穿刺活检(SB)+每个目标靶点(ROI)2针靶向穿刺活检(TB)。活检标本行病理学分析,获知Gleason评分和阳性单针癌组织长度。记录所有患者的临床、影像及病理资料,采用t检验、秩和检验、卡方检验等统计学方法对各项数据进行分析对比。结果:TB的前列腺癌单针阳性率(20.0%)以及高危前列腺癌单针阳性率(10.3%)均明显高于SB(12.7%和5.5%),差异均有统计学意义(P=0.001和P=0.002);TB的阳性单针癌组织长度高于SB,差异有统计学意义(P=0.046);TB的阳性针癌组织主要分化程度的Gleason评分、次要分化程度的Gleason评分、Gleason总评分均高于SB,但差异无统计学意义(P>0.05)。结论:MRI/US成像融合引导的前列腺穿刺活检中的TB较SB能够更有效地检出高危前列腺癌。在条件允许的情况下可推广应用MRI/US成像融合引导的前列腺穿刺活检技术。     

Preoperative nomograms incorporating magnetic resonance imaging and spectroscopy for prediction of insignificant prostate cancer

Study Type – Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Nomograms are available that combine clinical and biopsy findings to predict the probability of pathologically insignificant prostate cancer in patients with clinically low‐risk disease. Based on data from patients with Gleason score 6, clinical stage ≤ T2a and PSA <20 ng/ml, our group developed the first nomogram models for predicting insignificant prostate cancer that incorporated clinical data, detailed biopsy data and findings from MRI or MRI/MRSI (BJU Int. 2007;99(4):786–93). When tested retrospectively, these MR models performed significantly better than standard clinical models with and without detailed biopsy data. We prospectively validated the previously published MR‐based nomogram models in a population of patients with Gleason score 6, clinical stage ≤ T2a and PSA <10 ng/ml. Based on data from this same population, we also developed two new models for predicting insignificant prostate cancer that combine MR findings and clinical data without detailed biopsy data. Upon initial testing, the new MR models performed significantly better than a clinical model lacking detailed biopsy data.

OBJECTIVES

• ? To validate previously published nomograms for predicting insignificant prostate cancer (PCa) that incorporate clinical data, percentage of biopsy cores positive (%BC+) and magnetic resonance imaging (MRI) or MRI/MR spectroscopic imaging (MRSI) results.
• ? We also designed new nomogram models incorporating magnetic resonance results and clinical data without detailed biopsy data. Nomograms for predicting insignificant PCa can help physicians counsel patients with clinically low‐risk disease who are choosing between active surveillance and definitive therapy.

PATIENTS AND METHODS

• ? In total, 181 low‐risk PCa patients (clinical stage T1c–T2a, prostate‐specific antigen level <10 ng/mL, biopsy Gleason score of 6) had MRI/MRSI before surgery.
• ? For MRI and MRI/MRSI, the probability of insignificant PCa was recorded prospectively and independently by two radiologists on a scale from 0 (definitely insignificant) to 3 (definitely significant PCa).
• ? Insignificant PCa was defined on surgical pathology.
• ? There were four models incorporating MRI or MRI/MRSI and clinical data with and without %BC+ that were compared with a base clinical model without %BC and a more comprehensive clinical model with %BC+. Prediction accuracy was assessed using areas under receiver–operator characteristic curves.

RESULTS

• ? At pathology, 27% of patients had insignificant PCa, and the Gleason score was upgraded in 56.4% of patients.
• ? For both readers, all magnetic resonance models performed significantly better than the base clinical model (P ≤ 0.05 for all) and similarly to the more comprehensive clinical model.

CONCLUSIONS

• ? Existing models incorporating magnetic resonance data, clinical data and %BC+ for predicting the probability of insignificant PCa were validated.
• ? All MR‐inclusive models performed significantly better than the base clinical model.

     

Transrectal prostate biopsy and fiducial marker placement in a standard 1.5T magnetic resonance imaging scanner

PURPOSE: We investigated the accuracy and feasibility of a system that provides transrectal needle access to the prostate concurrent with 1.5 Tesla MRI which previously has not been possible. MATERIALS AND METHODS: In 5 patients with previously diagnosed prostate cancer, MRI guided intraprostatic placement of gold fiducial markers (4 procedures) and/or prostate biopsy (3 procedures) was performed using local anesthesia. RESULTS: Mean procedure duration was 76 minutes and all patients tolerated the intervention well. Procedure related adverse events included self-limited hematuria and hematochezia following 3 of 8 procedures (all resolved in less than 1 week). Mean needle placement accuracy was 1.9 mm for the fiducial marker placement studies and 1.8 mm for the biopsy procedures. Mean fiducial marker placement accuracy was 4.8 mm and the mean fiducial marker placement accuracy transverse to the needle direction was 2.6 mm. All patients who underwent the procedure were able to complete their course of radiotherapy without delay or complication. CONCLUSIONS: While studies of clinical usefulness are warranted, transrectal 1.5 T MRI guided prostate biopsy and fiducial marker placement is feasible using this system, providing new opportunities for image guided diagnostic and therapeutic prostate interventions.