The accuracy of prostate cancer diagnosis in biopsy-naive patients using combined magnetic resonance imaging and transrectal ultrasound fusion-targeted prostate biopsy

BackgroundThis study aimed to estimate whether multiparametric magnetic resonance imaging (mpMRI)-transrectal ultrasound (TRUS) fusion biopsy (FUS-TB) increases the detection rates of clinically significant prostate cancer (csPCa) compared with TRUS-guided systematic biopsy (TRUS-GB).MethodsThis retrospective study focused on patients who underwent mpMRI before prostate biopsy (PB) with Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) scores ≥3 and prostate-specific antigen (PSA) level between 2.5 and 20 ng/mL. Before FUS-TB, the biopsy needle position was checked virtually using three-dimensional mapping. After confirming the position of the target within the prostate, biopsy needle was inserted and PB was performed. Suspicious lesions were generally targeted with 2 to 4 cores. Subsequently, 10–12 cores were biopsied for TRUS-GB. The primary endpoint was the PCa detection rate (PCDR) for patients with PCa who underwent combined FUS-TB and TRUS-GB.ResultsAccording to PI-RADS v2, 76.7% of the patients with PI-RADS v2 score ≥3 were diagnosed with PCa. The PCDRs in patients with PI-RADS v2 score of 4 or 5 were significantly higher than those in patients with PI-RADS v2 score of 3 (3 vs. 4, P<0.001; 3 vs. 5, P<0.001; 4 vs. 5, P=0.073). According to PCDR, the detection rates of PCa and csPCa in the FUS-TB were significantly higher than that in the TRUS-GB.ConclusionsFollowing detection of suspicious tumor lesions on mpMRI, FUS-TB use detects a higher number of PCa cases compared with TRUS-GB.     

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.     

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.     

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.     

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。     

Systematic sampling during MRI-US fusion prostate biopsy can overcome errors of targeting—prospective single center experience after 300 cases in first biopsy setting

BackgroundMultiparametric magnetic resonance imaging (mpMRI) and targeted biopsy have become an integral part of the diagnosis of prostate cancer (PCa), as recommended by the European Association of Urology Guidelines. The aim of the current study was to evaluate the performance of MRI and MRI-transrectal ultrasound (TRUS) fusion prostate biopsy as first biopsy setting in a tertiary center.MethodsA cohort of 300 patients was included in the current analysis. All patients presented with clinical or biochemical suspicion of PCa and harbored at least one suspect lesion on mpMRI. MRI-TRUS fusion prostate biopsy, followed by 12 core systematic prostate biopsy were performed by the same operator using a rigid registration system.ResultsThe mean age of the patients was 64 years (IQR: 58–68.5 years) and the mean PSA was 6.35 ng/mL (IQR: 4.84–9.46 ng/mL). Overall cancer and csPCa diagnosis rates were 47% and 40.66%. Overall PCa/csPCa detection rates were 20.4%/11.1%, 52%/45% and 68.5%/66.7% for PI-RADS lesions 3, 4 and 5 (P<0.001/P<0.0001). Larger lesion diameter and lesion volume were associated with PCa diagnosis (P=0.006 and P=0.001, respectively). MRI-TRUS fusion biopsy missed PCa diagnosis in 37 cases (of whom 48.6% ISUP 1) in comparison with 9 patients missed by systematic biopsy (of whom 11.1% ISUP 1). In terms of csPCa, systematic biopsy missed 77.7% of the tumors located in the anterior and transitional areas. The rate of csPCa was highest when targeted biopsy was associated with systematic biopsy: 86.52% vs. 68.79% for targeted biopsy vs. 80.14% for systematic biopsy, P=0.0004. In 60.6% of cases, systematic biopsy was positive for PCa at the same site as the targeted lesion. Of these patients, eight harbored csPCa and were diagnosed exclusively on systematic biopsy.ConclusionsMRI-TRUS fusion prostate biopsy improves the diagnosis of csPCa. The main advantage of an MRI-guided approach is the diagnosis of anterior and transitional area tumors. The best results in terms of csPCa diagnosis are obtained by the combination of MRI-TRUS fusion with systematic biopsy. The systematic biopsy performed during MRI-targeted biopsy could have an important role in overcoming errors of MRI-TRUS fusion systems.     

Initial clinical experience with real-time transrectal ultrasonography-magnetic resonance imaging fusion-guided prostate biopsy

OBJECTIVE

To evaluate the feasibility and utility of registration and fusion of real‐time transrectal ultrasonography (TRUS) and previously acquired magnetic resonance imaging (MRI) to guide prostate biopsies.

PATIENTS AND METHODS

Two National Cancer Institute trials allowed MRI‐guided (with or with no US fusion) prostate biopsies during placement of fiducial markers. Fiducial markers were used to guide patient set‐up for daily external beam radiation therapy. The eligible patients had biopsy‐confirmed prostate cancer that was visible on MRI. A high‐field (3T) MRI was performed with an endorectal coil in place. After moving to an US suite, the patient then underwent TRUS to visualize the prostate. The US transducer was equipped with a commercial needle guide and custom modified with two embedded miniature orthogonal five‐degrees of freedom sensors to enable spatial tracking and registration with MR images in six degrees of freedom. The MRI sequence of choice was registered manually to the US using custom software for real‐time navigation and feedback. The interface displayed the actual and projected needle pathways superimposed upon the real‐time US blended with the prior MR images, with position data updating in real time at 10 frames per second. The registered MRI information blended to the real‐time US was available to the physician who performed targeted biopsies of highly suspicious areas.

RESULTS

Five patients underwent limited focal biopsy and fiducial marker placement with real‐time TRUS‐MRI fusion. The Gleason scores at the time of enrolment on study were 8, 7, 9, 9, and 6. Of the 11 targeted biopsies, eight showed prostate cancer. Positive biopsies were found in all patients. The entire TRUS procedure, with fusion, took ≈10 min.

CONCLUSION

The fusion of real‐time TRUS and prior MR images of the prostate is feasible and enables MRI‐guided interventions (like prostate biopsy) outside of the MRI suite. The technique allows for navigation within dynamic contrast‐enhanced maps, or T2‐weighted or MR spectroscopy images. This technique is a rapid way to facilitate MRI‐guided prostate therapies such as external beam radiation therapy, brachytherapy, cryoablation, high‐intensity focused ultrasound ablation, or direct injection of agents, without the cost, throughput, or equipment compatibility issues that might arise with MRI‐guided interventions inside the MRI suite.