Comparison of pelvic phased-array versus endorectal coil magnetic resonance imaging at 3 Tesla for local staging of prostate cancer

Impact of Endorectal Coil Use on Extraprostatic Extension Detection in Prostate MRI: A Retrospective Monocentric Study

RATIONALE AND OBJECTIVES

Accurate preoperative mpMRI-based detection of extraprostatic extension (EPE) in prostate cancer (PCa) is critical for surgical planning and patient outcomes. This study aims to evaluate the impact of endorectal coil (ERC) use on the diagnostic performance of mpMRI in detecting EPE.

MATERIALS AND METHODS

This retrospective study with prospectively collected data included participants who underwent mpMRI and subsequent radical prostatectomy for PCa between 2007 and 2024. Participants were divided based on ERC use on mpMRI: MRI without ERC and with ERC. Surgical pathology reports were used to determine the patients with pathologic EPE on whole-mount histopathology. One radiologist evaluated mpMRI using an in-house (National Cancer Institute [NCI]) EPE grading system. Logistic regression (LR) analyses were conducted to identify significant predictors of pathologic EPE, including ERC use and NCI EPE grades.

RESULTS

934 men (median age: 62 years [IQR = 57-67]) were included. For NCI EPE grade≥1, ERC MRI group (n = 612) had higher NPV (91% [320/353] vs. 83% [166/200], p = 0.01) and sensitivity (75% [101/134] vs. 62% [56/90], p = 0.04) compared to non-ERC group (n = 322). For NCI EPE grade = 3, ERC MRI group had higher NPV (83% [452/546] vs. 75% [221/294], p = 0.01) and accuracy (80% [492/612] vs. 74% [238/322], p = 0.03). In multivariable LR, higher NCI EPE grades were strong independent predictors of pathologic EPE, irrespective of ERC use (NCI EPE grade 2 with ERC: odds ratio [OR] = 2.01, p = 0.04; without ERC: OR = 5.63, p<0.001, NCI EPE grade 3 with ERC: OR = 4.53, p<0.001; without ERC: OR = 5.22, p = 0.002).

CONCLUSION

ERC improves sensitivity, NPV, accuracy of EPE detection with mpMRI at different NCI EPE thresholds. NCI EPE grading system remains the stronger independent predictor of pathologic EPE regardless of ERC use.

Picture Perfect: The Status of Image Quality in Prostate MRI

Magnetic resonance imaging is the gold standard imaging modality for the diagnosis of prostate cancer (PCa). Image quality is a fundamental prerequisite for the ability to detect clinically significant disease. In this critical review, we separate the issue of image quality into quality improvement and quality assessment. Beginning with the evolution of technical recommendations for scan acquisition, we investigate the role of patient preparation, scanner factors, and more advanced sequences, including those featuring Artificial Intelligence (AI), in determining image quality. As means of quality appraisal, the published literature on scoring systems (including the Prostate Imaging Quality score), is evaluated. Finally, the application of AI and teaching courses as ways to facilitate quality assessment are discussed, encouraging the implementation of future image quality initiatives along the PCa diagnostic and monitoring pathway. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Prostate MRI and image Quality: It is time to take stock

Multiparametric magnetic resonance imaging (mpMRI) plays a vital role in prostate cancer diagnosis and management. With the increase in use of mpMRI, obtaining the best possible quality images has become a priority. The Prostate Imaging Reporting and Data System (PI-RADS) was introduced to standardize and optimize patient preparation, scanning techniques, and interpretation. However, the quality of the MRI sequences depends not only on the hardware/software and scanning parameters, but also on patient-related factors. Common patient-related factors include bowel peristalsis, rectal distension, and patient motion. There is currently no consensus regarding the best approaches to address these issues and improve the quality of mpMRI. New evidence has been accrued since the release of PI-RADS, and this review aims to explore the key strategies which aim to improve prostate MRI quality, such as imaging techniques, patient preparation methods, the new Prostate Imaging Quality (PI-QUAL) criteria, and artificial intelligence on prostate MRI quality.

Prostate MRI: Is Endorectal Coil Necessary?—A Review

To assess the necessity of endorectal coil use in 3 Tesla (T) prostate magnetic resonance imaging (MRI), a literature review comparing the image quality and diagnostic performance with an endorectal coil (ERC) and a without endorectal coil (NERC), with a phased array coil or a wearable perineal coil (WPC), was performed. A PubMed search of 3T prostate MRI using an endorectal coil for studies published until 31 July 2021 was performed. A total of 14 studies comparing 3T prostate MRI with and without endorectal coil use were identified. The quality scores and diagnostic performances were recorded for each study. In total, five studies compared image quality; five studies compared quality and performance; and four studies compared performance of detection, size of detected lesions, accuracy of cancer localization, and aggressiveness/staging. The use of an endorectal coil improved image quality with a higher overall signal to noise ratio, posterior and peripheral zone signal to noise ratio, high b-value attenuation diffusion coefficient (ADC) signal to noise ratio, and contrast to noise ratio. Endorectal coil use improved subjective image quality for anatomic detail on T2 weighted images (T2WI) and diffusion weighted images (DWI). Endorectal coil use had less motion artifact on DWI than non-endorectal coil use, but produced a higher occurrence of other artifacts on DWI. Endorectal coils had higher sensitivity, specificity, and positive predictive value (PPV) in the detection of overall and index lesions, as well as smaller and less aggressive lesions, missing fewer and smaller lesions than non-endorectal coils. Endorectal coils had higher sensitivity than non-endorectal coils in localizing and staging lesions. Endorectal coils improved quantitative and qualitative image quality and diagnostic performance in the detection of smaller and less aggressive cancers in 3T prostate MRI.

Prostate MRI using a rigid two-channel phased-array endorectal coil: comparison with phased array coil acquisition at 3 T

Background

To compare image quality, lesion detection and patient comfort of 3T prostate MRI using a combined rigid two-channel phased-array endorectal coil and an external phased-array coil (ERC-PAC) compared to external PAC acquisition in the same patients.

Methods

Thirty three men (mean age 65.3y) with suspected (n = 15) or biopsy-proven prostate cancer (PCa, n = 18) were prospectively enrolled in this exploratory study. 3T prostate MRI including T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) was performed using an ERC-PAC versus PAC alone, in random order. Image quality, lesion detection and characterization (biparametric PI-RADSv2.1) were evaluated by 2 independent observers. Estimated signal-to-noise ratio (eSNR) was measured in identified lesions and the peripheral zone (PZ). Patient comfort was assessed using a questionnaire. Data were compared between sequences and acquisitions. Inter/intra-observer agreement for PI-RADS scores was evaluated.

Results

Twenty four prostate lesions (22 PCa) were identified in 20/33 men. Superior image quality was found for ERC-PAC compared to PAC for T2WI for one observer (Obs.1, p < 0.03) and high b-value DWI for both observers (p < 0.05). The sensitivity of PI-RADS for lesion detection for ERC-PAC and PAC acquisitions was 79.2 and 75% for Obs.1, and 79.1 and 66.7%, for Obs.2, without significant difference for each observer (McNemar p-values ≥0.08). Inter−/intra-observer agreement for PI-RADS scores was moderate-to-substantial (kappa = 0.52–0.84). Higher eSNR was observed for lesions and PZ for T2WI and PZ for DWI using ERC-PAC (p < 0.013). Most patients (21/33) reported discomfort at ERC insertion.

Conclusion

Despite improved image quality and eSNR using the rigid ERC-PAC combination, no significant improvement in lesion detection was observed, therefore not supporting the routine use of ERC for prostate MRI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-022-00453-7.

Three-dimensional nuclear magnetic resonance spectroscopy: a complementary tool to multiparametric magnetic resonance imaging in the identification of aggressive prostate cancer at 3.0T

Background

The limitations of the assessment of tumor aggressiveness by Prostate Imaging Reporting and Data System (PI-RADS) and biopsies suggest that the diagnostic algorithm could be improved by quantitative measurements in some chosen indications. We assessed the tumor high-risk predictive performance of 3.0 Tesla (3.0T) multiparametric magnetic resonance imaging (mp-MRI) combined with nuclear magnetic resonance spectroscopic sequences (NMR-S) in order to show that the metabolic analysis could bring out an evocative result for the aggressive form of prostate cancer.

Methods

We conducted a retrospective study of 26 patients (mean age, 62.4 years) who had surgery for prostate cancer between 2009 and 2016 after pre-therapeutic assessment with 3.0T mp-MRI and NMR-S. Groups within the intermediate range of the D'Amico risk classification were divided into two categories, low risk (n=20) and high risk (n=6), according to the International Society of Urological Pathology (ISUP) 2-3 limit. Histoprognostic discordances within various risk groups were compared with the corresponding predictive MRI values. The performance of predictive models was assessed based on sensitivity, specificity, and the area under the curve (AUC) of receiver operating characteristic (ROC) curves.

Results

After prostatectomy, histological analysis reclassified 18 patients as high-risk, including 16 who were T3 MRI grade, of whom 13 (81.3%) were found to be pT3. Among the patients who had cT1 or cT2 digital rectal examinations, the T3 MRI factor multiplied by 8.7 [odds ratio (OR), 8.7; 95% confidence interval (CI), 1.3-56.2; P=0.024] the relative risk of being pT3 and by 5.8 (OR, 5.8; 95% CI, 0.95-35.7; P=0.05) the relative risk of being pGleason (pGS) > GS-prostate biopsy. Spectroscopic data showed that the choline concentration was significantly higher (P=0.001) in aggressive disease.

Conclusions

The predictive model of tumor aggressiveness combining mp-MRI plus NMR-S was better than the mp-MRI model alone (AUC, 0.95 vs. 0.86). Information obtained by mp-MRI coupled with spectroscopy may improve the detection of occult aggressive disease, helping in the discrimination of intermediate risks.

Quality Comparison of 3 Tesla multiparametric MRI of the prostate using a flexible surface receiver coil versus conventional surface coil plus endorectal coil setup

PURPOSE

To subjectively and quantitatively compare the quality of 3 Tesla magnetic resonance imaging of the prostate acquired with a novel flexible surface coil (FSC) and with a conventional endorectal coil (ERC).

METHODS

Six radiologists independently reviewed 200 pairs of axial, high-resolution T2-weighted and diffusion-weighted image data sets, each containing one examination acquired with the FSC and one with the ERC, respectively. Readers selected their preferred examination from each pair and assessed every single examination using six quality criteria on 4-point scales. Signal-to-noise ratios were measured and compared.

RESULTS

Two readers preferred FSC acquisition (36.5-45%) over ERC acquisition (13.5-15%) for both sequences combined, and four readers preferred ERC acquisition (41-46%). Analysis of pooled responses for both sequences from all readers shows no significant preference for FSC or ERC. Analysis of the individual sequences revealed a pooled preference for the FSC in T2WI (38.7% vs 17.8%) and for the ERC in DWI (50.9% vs 19.6%). Patients' weight was the only weak predictor of a preference for the ERC acquisition (p = 0.04). SNR and CNR were significantly higher in the ERC acquisitions (p<0.001) except CNR differentiating tumor lesions from benign prostate (p=0.1).

CONCLUSION

Although readers have strong individual preferences, comparable subjective image quality can be obtained for prostate MRI with an ERC and the novel FSC. ERC imaging might be particularly valuable for sequences with inherently lower SNR as DWI and larger patients whereas the FSC is generally preferred in T2WI. FSC imaging generates a lower SNR than with an ERC.

Doctor, a patient is on the phone asking about the endorectal coil!

The question referred to in the title of this article is a relatively common situation when performing prostate MRI in some healthcare settings. Moreover, the answer is not always straightforward. The decisions on type of receiver coil for prostate MRI and whether or not an endorectal coil (ERC) should be used is based on several factors. These relate to the patient (e.g., body habitus, presence of metallic devices in the pelvis), the focus of the exam (diagnosis, staging, recurrence), and characteristics of the MRI system (e.g., magnetic field strength and hardware components including coil design and number of elements/channels available in the surface coil). Historically, the combined use of an ERC and a surface coil was the optimal combination for maximizing the signal-to-noise ratio (SNR), particularly for low-strength magnetic fields (1.5T). However, there are several disadvantages associated with the use of an ERC, and several studies have advocated equivalent clinical performance of modern MRI systems for diagnosis and staging of prostate cancer (PCa), either with ERC or surface alone. Accordingly, there is a wide variation in the precise imaging technique across institutions. This article focuses on the most relevant aspects of the decision of whether to use an ERC for PCa MR imaging.

Prostate magnetic resonance imaging technique

Multiparametric magnetic resonance (MR) imaging of the prostate is an excellent tool to detect clinically significant prostate cancer, and it has widely been incorporated into clinical practice due to its excellent tissue contrast and image resolution. The aims of this article are to describe the prostate MR imaging technique for detection of clinically significant prostate cancer according to PI-RADS v2.1, as well as alternative sequences and basic aspects of patient preparation and MR imaging artifact avoidance.

Local staging of prostate cancer with multiparametric-MRI: accuracy and inter-reader agreement

Background

The accuracy of prostate cancer local staging at the time of diagnosis directly influences patient prognosis and treatment.

Aim

To evaluate the diagnostic performance and interobserver variability of mp-MRI in local staging of prostate cancer, using the histopathologic findings at prostatectomy as the reference standard.

Methods

Fifty patients (mean age 64.4±7.2) with biopsy confirmed prostate cancer were included in this prospective study. All patients were examined with mp-MRI before radical prostatectomy and images were read by three independent radiologists. Sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy rate were calculated and compared for all three readers. Interobserver agreement was evaluated using Kappa Cohen coefficient of agreement.

Results

The overall Se, Sp, PPV, NPV and accuracy rates for detecting extraprostatic tumor extension (EPE) ranged between 76.5-94.1%, 45.5-84.9%, 43.8-76.2%, 83.3-96.6% and 58-88%. For evaluation of seminal vesicle invasion (SVI), the overall Se, Sp, PPV, NPV and accuracy rates ranged between 57.1-85.7%, 86.1-97.7%, 40.0-85.7%, 92.5-97.7% and 82-96%, respectively. The overall Kappa Cohen coefficient of agreement varied between 0.349-0.638 for EPE and between 0.507-0.668 for SVI.

Conclusions

Our results showed that 1.5T mp-MRI is a reliable method for local staging of prostate cancer, with good diagnostic performance in detecting EPE and SVI. The overall interobserver agreement rates between readers with the same level of experience in prostate MRI ranged from fair to good in the evaluation of EPE and from moderate to good for the assessment of SVI.

MRI of the Prostate With and Without Endorectal Coil at 3 T: Correlation With Whole-Mount Histopathologic Gleason Score

OBJECTIVE. The purpose of this article is to prospectively compare image quality and diagnostic accuracy of clinically significant prostate cancer with and without endorectal coil (ERC) at 3 T using a combination of T2-weighted and diffusion-weighted MRI. SUBJECTS AND METHODS. Twenty-three patients with biopsy-proven prostate cancer underwent MRI with and without ERC at the same visit. Patients subsequently underwent radical prostatectomy. Specimens were assessed by whole-mount histopathologic examination. Two radiologists reviewed MR images for image quality (5-point scale) and disease using Prostate Imaging Reporting and Data Systems version 2 (PI-RADSv2). Sensitivity, specificity, and area under the ROC curve (AUC) were calculated with and without ERC. Additionally, apparent diffusion coefficient (ADC) was correlated with Gleason score and ADC values of each lesion were compared with and without ERC. RESULTS. Image quality was comparable with and without ERC (3.8 vs 3.5). Twenty-nine cancer foci larger than 0.5 cm in diameter were found in 23 patients on histopathologic examination; 18 tumors had a Gleason score of 7 or greater. Two radiologists recorded AUC for tumors with a Gleason score of 7 or greater as 0.96 and 0.96 with ERC and 0.88 and 0.91 without ERC. All 13 tumors with a Gleason score of 3 + 4 were detected with ERC, but only 9 were detected without ERC. One of five tumors with Gleason scores less than 3 + 4 was missed with and without ERC. ADC significantly correlated with Gleason score. There was no significant difference in the ADC of a lesion on MRI with and without an ERC. CONCLUSION. MRI with and without ERC was equally accurate at showing prostate cancers with Gleason scores of 4 + 3 or greater. However, MRI with ERC was superior at showing cancer with a Gleason score of 3 + 4. There was no significant difference in ADC values between scores acquired with or without an ERC.

Head-to-head comparison of prostate MRI using an endorectal coil versus a non-endorectal coil: meta-analysis of diagnostic performance in staging T3 prostate cancer

AIM

To compare the diagnostic performance of prostate magnetic resonance imaging (MRI) with an endorectal coil (ERC) to performance without an ERC using either body-array (BAC) or pelvic phased-array coil (PAC) in staging T3 prostate cancer.

MATERIALS AND METHODS

An electronic search of the PUBMED and EMBASE databases was performed until 10 October 2018 to identify studies performing a head-to-head comparison of prostate MRI using a 1.5 or 3 T magnet with an ERC and with a BAC/PAC for staging T3 prostate cancer. Pooled sensitivity and specificity of all studies were plotted in a hierarchical summary receiver operating characteristic plot. The diagnostic performance of the two techniques in staging T3 disease was evaluated using bivariate random-effects meta-analysis.

RESULTS

Eight studies comparing head-to-head prostate MRI with an ERC and with a BAC/PAC were identified of which six studies compared the diagnostic performance. The pooled sensitivity and specificity of MRI with an ERC for detecting T3a, T3b and T3a+b was 53% and 95%; 52% and 92%; 72% and 65% respectively. For MRI with a BAC/PAC these were 34%, and 95%; 45% and 94%; 70% and 66%. There was no statistical difference between an ERC and a BAC/PAC in terms of sensitivity (p=0.41) and specificity (p=0.63) for T3a. The area under the receiver operating characteristic (AUROC) curve for T3a, T3b and T3a+b was 0.830, 0.901, 0.741 for an ERC and 0.790, 0.645, 0.711 for BAC, respectively.

CONCLUSION

There is no significant difference in the diagnostic performance of MRI of prostate with an ERC and with a BAC/PAC in staging T3 prostate cancer.

Two-centre comparative experimental study of biparametric MRI at 3.0 T with and without endorectal coil using kiwifruit (Actinidia deliciosa) as a phantom for human prostate

BACKGROUND

Application of an endorectal coil (ERC) for 3.0-T prostate magnetic resonance imaging (MRI) is contentious. We hypothesised that a multicoil phased-array protocol provides T2-weighted images (T2WI) and diffusion-weighted images (DWI) with reduced field-of-view (DWI_reduced) and monoexponential apparent diffusion coefficient (ADC) maps that are technically equivalent with ERC or without ERC (noERC).

METHODS

Axial T2WI (repetition time [TR] 7500 ms, echo time [TE] 98-101 ms) and DWI_reduced (field-of-view 149-179 × 71-73 mm², TR/TE 4500-5500/61-74 ms, b values, 50/800 s/mm²) ERC and noERC images were obtained on identical clinical 3.0-T scanners at two centres and compared for signal-to-noise ratio (SNR) in anterior and posterior outer pericarp (OP) and peripheral placenta (PP) in five green Hayward kiwifruit (Actinidia deliciosa, European Union regulation 543/2011 class 2). Corroboration in 21 patients with benign prostate hyperplasia (negative biopsy, prostate imaging reporting and data system version 2 ≤ 2) involved identical MRI protocols: 10 at site 1, noERC, and 11 at site 2, with ERC. Two-tailed Student's t test was used.

RESULTS

With few exceptions, signal-to-noise ratio (SNR) was similar in kiwifruits and prostates for ERC and noERC. In T2WI, SNR was higher posteriorly in noERC MRI for peripheral zone (PZ) (p < 0.001). In DWI_reduced, SNR was higher posteriorly in ERC-OP (p = 0.013) and ERC-PZ (p = 0.026) for b = 50 s/mm²; noERC-OP (p = 0.044) and ERC-PZ (p = 0.001) for b = 800 s/mm²; and ERC-OP (p = 0.001), noERC-OP (p = 0.001), and ERC-PZ (p = 0.001) for ADC, respectively. Volumes of kiwifruits and prostates were similar (89.2 ± 11.2 versus 90.8 ± 48.5 cm³, p = 0.638-0.920).

CONCLUSIONS

Findings imply that multicoil phased-array 3.0-T prostate MRI with T2WI and DWI_reduced with ADC maps provides equivalent results with and without ERC.

Defining the incremental value of 3D T2-weighted imaging in the assessment of prostate cancer extracapsular extension

Objectives

To assess the added value of 3D T2-weighted imaging (T2WI) over conventional 2D T2WI in diagnosing extracapsular extension (ECE).

Methods

Seventy-five patients undergoing 3-T MRI before radical prostatectomy were included. PI-RADS ≥ 4 lesions were assessed for ECE on 2D T2W images using a 5-point Likert scale (1 = no ECE, 5 = definite ECE) and the length of tumour prostatic capsular contact. A second read using 3D T2W images and reformats evaluated ECE and the maximal 3D capsular contact length and surface.

Results

One hundred six lesions were identified at MRI. ECE was confirmed by histology in 54% (57/106) of lesions and 64% (48/75) of patients. Sensitivity and specificity for 3D T2 reads were 75.4% versus 64.9% (p = 0.058), respectively, and 83.7% versus 85.7% (p = 0.705) for 2D T2 reads, respectively. 3D T2W reads showed significantly higher mean subjective Likert scores of 3.7 ± 1.4 versus 3.3 ± 1.4 (p = 0.001) in ECE-positive lesions and lower mean Likert score of 1.5 ± 1 versus 1.6 ± 0.9 (p = 0.27) in ECE-negative lesions compared with 2D T2W reads. 3D contact significantly increased sensitivity from 59.6 to 73.7% (p = 0.03), whilst maintaining the same specificity of 87.8% (p = 1). High-grade group tumours (≥ Gleason 4 + 3) showed significantly higher ECE prevalence than low-grade tumours (88% versus 44%, p < 0.001) and a positive predictive value (PPV) for ECE of 90.9% with ≥ 5 mm of contact versus PPV of 90.4% at ≥ 12.5 mm for lower grade tumours.

Conclusions

3D T2WI significantly increases sensitivity and confidence in calling ECE. The capsular contact length threshold differed between low- and high-grade cancers.

Key Points

• 3D capsular contact length and 3D surface contact significantly increased sensitivity in diagnosing ECE.

• 3D T2W reads significantly increased reader confidence in calling ECE.

• Thresholds for capsular contact length differed between low-grade and high-grade cancers.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06070-6) contains supplementary material, which is available to authorized users.

Evaluation of stacked resonators to enhance the performance of a surface receive-only array for prostate MRI at 3 Tesla

Prostate MRI is an important tool to diagnose and characterize cancer. High local sensitivity and good parallel imaging performance are of paramount importance for diagnostic quality and efficiency. The purpose of this work was to evaluate stacked resonators as part of a surface receiver array for prostate MRI at 3 Tesla. A base array of 6-channels consisting of a flexible anterior and a rigid posterior part were built each with three loop coils. A pair of stacked resonators was added concentrically to the center loops (anterior and posterior) of the base array. The evaluated stacked resonators were butterflies, composites and dipoles which yielded a total of three 8-channel arrays. The arrays were compared using noise correlations and single-channel signal-to-noise ratio maps in a phantom. Combined signal-to-noise ratio maps and parallel imaging performances were measured and compared in vivo in 6 healthy volunteers. The results were compared to the base and a commercial array. The SNR values in the prostate yielded by all the arrays were not statistically different using fully sampled k-space. However, significant differences were found in the parallel imaging performance of the arrays. More specifically, up to 88% geometric factor reduction was found compared to the commercial array and up to 83% reduction compared to the base array using butterfly coils. Thus, signal-to-noise ratio improvements were observed with stacked resonators when using parallel imaging. The use of stacked elements, in particular butterfly coils, can improve the performance of a base array consisting solely of single loops when using parallel imaging. We expect prostate MRI at 3 Tesla to benefit from using combinations of single loops and stacked resonators.

The emerging role of imaging in prostate cancer secondary screening: multiparametric magnetic resonance imaging and the incipient incorporation of molecular imaging

An increasingly robust body of evidence indicates that multiparametric MRI (mpMRI) prior to prostate biopsy can improve the detection of clinically significant prostate cancer while avoiding unnecessary biopsies. As a result, the use of mpMRI and biopsy platforms that allow for the real-time fusion of mpMRI and transrectal ultrasound images is now routinely used in clinical practice. On the horizon, molecular imaging offers the promise of improved sensitivity relative to mpMRI and early data would suggest that the combination of mpMRI and positron emission tomography using radiotracers targeting prostate-specific membrane antigen provide a more accurate assessment than either modality alone. In this review, we examine the current role of imaging to aid in the initial diagnosis of prostate cancer.

A systematic review on multiparametric MR imaging in prostate cancer detection

BACKGROUND

Literature data suggest that multi-parametric Magnetic Resonance Imaging (MRI), including morphologic T2-weigthed images (T2-MRI) and functional approaches such as Dynamic Contrast Enhanced-MRI (DCE-MRI), Diffusion Weighted Imaging (DWI) and Magnetic Resonance Spectroscopic Imaging (MRSI), give an added value in the prostate cancer localization and local staging.

METHODS

We performed a systematic review of literature about the role and the potentiality of morphological and functional MRI in prostate cancer, also in a multimodal / multiparametric approach, and we reported the diagnostic accuracy results for different imaging modalities and for different MR coil settings: endorectal coil (ERC) and phased array coil (PAC). Forest plots and receiver operating characteristic curves were performed. Risk of bias and the applicability at study level were calculated.

RESULTS

Thirty three papers were identified for the systematic review. Sensitivity and specificity values were, respectively, for T2-MRI of 75% and of 60%, for DCE-MRI of 80% and of 72%, for MRSI of 89% and of 69%, for combined T2-MRI and DCE-MRI of 87% and of 46%, for combined T2-MRI and MRSI of 79% and of 57%, for combined T2-MRI, DWI and DCE-MRI of 81% and of 84%, and for combined MRSI and DCE-MRI of 83% and of 83%. For MRI studies performed with ERC we obtained a pooled sensitivity and specificity of 81% and of 66% while the pooled values for MRI studies performed with PAC were of 78% and of 64%, respectively (p>0.05 at McNemar test). No studies were excluded from the analysis based on the quality assessment.

CONCLUSIONS

ERC use yielded no additional benefit in terms of prostate cancer detection accuracy compared to multi-channel PAC use (71% versus 68%) while the use of additional functional imaging techniques (DCE-MRI, DWI and MRSI) in a multiparametric MRI protocol improves the accuracy of prostate cancer detection allowing both the early cure and the guidance of biopsy.

Impact of the use of an endorectal coil for 3 T prostate MRI on image quality and cancer detection rate

This work aims to assess the impact of an additional endorectal coil on image quality and cancer detection rate within the same patients. At a single academic medical center, this transversal study included 41 men who underwent T2- and diffusion-weighted imaging at 3 T using surface coils only or in combination with an endorectal coil in the same session. Two blinded readers (A and B) randomly evaluated all image data in separate sessions. Image quality with respect to localization and staging was rated on a five-point scale. Lesions were classified according to their prostate imaging reporting and data system (PIRADS) score version 1. Standard of reference was provided by whole-mount step-section analysis. Mean image quality scores averaged over all localization-related items were significantly higher with additional endorectal coil for both readers (p < 0.001), corresponding staging-related items were only higher for reader B (p < 0.001). With an endorectal coil, the rate of correctly detecting cancer per patient was significantly higher for reader B (p < 0.001) but not for reader A (p = 0.219). The numbers of histologically confirmed tumor lesions were rather similar for both settings. The subjectively rated 3-T image quality was improved with an endorectal coil. In terms of diagnostic performance, the use of an additional endorectal coil was not superior.

The role of imaging in the diagnosis of primary prostate cancer

Ultrasound and magnetic resonance imaging (MRI) are key imaging modalities in prostate cancer diagnosis. MRI offers a range of intrinsic contrast mechanisms (T2, diffusion-weighted imaging (DWI), MR spectroscopy (MRS)) and extrinsic contrast-generating options based on tumour vascular state following injection of weakly paramagnetic agents such as gadolinium. Together these parameters are referred to as multiparametric (mp)MRI and are used for detecting and guiding biopsy and staging prostate cancer. Although sensitivity of mpMRI is <75% for disease detection, specificity is >90% and a standardised reporting system together with MR-guided targeted biopsy is the optimal diagnostic pathway. Shear wave ultrasound elastography is a new technique which also holds promise for future studies. This article describes the developments in imaging the primary site of prostate cancer and reviews their current and future utility for screening, diagnosis and T-staging the disease.

Comparison of image quality and patient discomfort in prostate MRI: pelvic phased array coil vs. endorectal coil

PURPOSE

To compare image quality (IQ) and patient discomfort during prostate MRI using a pelvic phased array (PPA) coil and an endorectal (ER) coil.

MATERIALS AND METHODS

Ninety-eight patients (median age, 65.7; range 42.1-78.1) underwent prostate MRI on a 3T scanner including T2w and DWI acquired with PPA and an ER coil within the same exam. Acquisition time was kept similar for both acquisitions. Two radiologists evaluated aspects of IQ on a 5-point Likert scale and classified image artifacts. All patients completed a questionnaire on discomfort/pain regarding the ER coil using a visual analogue scale from 1 to 10.

RESULTS

There was no significant difference in overall IQ for T2w images for both readers (reader 1, 3.27 ± 0.91 and 3.07 ± 0.84, p = 0.057; reader 2, 3.70 ± 0.75 and 3.77 ± 0.81, p = 0.555) for PPA and ER coils, respectively. Overall IQ for DWI acquired with PPA and ER coils was rated similar by reader 1 (3.03 ± 1.10 and 3.08 ± 0.80, respectively, (p = 0.67)), while reader 2 preferred ER coil images (3.27 ± 0.81 and 3.66 ± 0.85 (p < 0.05)). Susceptibility artifacts were more frequent in ER than in PPA coil images (109 vs. 75). Discomfort and pain experienced during insertion of the ER coil was low altogether (VAS score, 3.5 ± 2.1 for "discomfort" and 2.4 ± 2.4 for "pain").

CONCLUSION

T2-weighted images may be acquired with comparable IQ using a PPA coil as compared to an ER coil, while DWI images showed better IQ using the ER coil for one of two readers. The insertion of the ER coil caused low to moderate discomfort and pain in patients.

Multiparametric magnetic resonance imaging for pre-treatment local staging of prostate cancer: A Cancer Care Ontario clinical practice guideline

INTRODUCTION

The utility of T2-weighted magnetic resonance imaging (MRI) in the local staging of prostate cancer is controversial. Due to the success of multiparametric MRI in cancer localization, there is renewed interested in MRI (± functional sequences) for local staging. Guidance on pre-treatment local staging of prostate cancer by MRI was developed using systematic review methodology and expert consultation.

METHODS

MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and other databases were searched to identify studies comparing: (1) MRI staging vs. radical prostatectomy staging on diagnostic accuracy outcomes; and (2) MRI staging vs. routine clinical staging on clinical and patient outcomes. Studies meeting inclusion criteria were synthesized by outcome and sensitivity/specificity analysis by tumour location was performed. Evidence quality of included studies was assessed and considered in recommendation formulation.

RESULTS

The literature search identified 2510 citations; 62 studies were included. Analysis of MRI ≥1.5 T plus endorectal coil (ER) (± functional sequences) in the detection of extraprostatic extension or seminal vesicle invasion showed modest sensitivities (≥50%) and excellent specificities (>85%) among patients scheduled for radical prostatectomy. MRI upstaging was shown in 20/21 studies, with large variation in correctness (11-85%). Scarcity of clinical and patient outcomes among studies limited synthesis and evaluation. Quality assessment found non-trivial biases.

CONCLUSIONS

Modest imaging performance was shown for MRI (1.5 T + ER and 3 T ± ER) ± functional sequences in regards to sensitivity. Limitations in study design, reporting of clinical and patient outcomes, and the heterogeneous use of MRI tempered the strength of the recommendations.

Multiparametric prostate magnetic resonance imaging in the evaluation of prostate cancer

Imaging has traditionally played a minor role in the diagnosis and staging of prostate cancer. However, recent controversies generated by the use of prostate-specific antigen (PSA) screening followed by random biopsy have encouraged the development of new imaging methods for prostate cancer. Multiparametric magnetic resonance imaging (mpMRI) has emerged as the imaging method best able to detect clinically significant prostate cancers and to guide biopsies. Here, the authors explain what mpMRI is and how it is used clinically, especially with regard to high-risk populations, and we discuss the impact of mpMRI on treatment decisions for men with prostate cancer. CA Cancer J Clin 2016;66:326-336. © 2015 American Cancer Society.

Comparison of prostate cancer detection at 3-T MRI with and without an endorectal coil: A prospective, paired-patient study

OBJECTIVES

To compare the sensitivity of 2 different non-endorectal coil strategies vs. endorectal coil (ERC) magnetic resonance imaging (MRI) for detection of prostate cancer (PCa).

METHODS

In this prospective, single-center, paired-patient, paired-reader study, 49 men with a clinical indication for MRI underwent non-ERC (phased-array coil only) T2-weighted imaging and diffusion-weighted imaging followed by the same sequences using both ERC and phased-array coils (ERC Protocol). Patients were randomized into 1 of 2 arms: standard non-ERC protocol and augmented non-ERC protocol. Lesions with Likert score≥3 were defined as suspicious for cancer. Radical prostatectomy specimen or combined systematic plus targeted biopsies served as the standard of reference. Cancers were stratified into risk groups according to the National Comprehensive Cancer Network guidelines. Generalized estimating equations with Bonferroni correction were used for comparisons. The level of reader confidence was inferred by the Likert scores assigned to index lesions.

RESULTS

The ERC protocol provided sensitivity (78%) superior to MRI without ERC for PCa detection, both with a standard (43%) (P<0.0001) or augmented (60%) (P<0.01) protocol. The ERC MRI missed less-intermediate or high-risk index lesions (4%) than standard non-ERC (42%) (P = 0.02) and augmented non-ERC MRI (25%), although the latter did not reach significance (P = 0.09). The ERC improved radiologist confidence for the detection of PCa (average Likert score = 4.2±1.4) compared to standard (2.3±2.3) and augmented (2.9±2.1) non-ERC (P = 0.001).

CONCLUSIONS

The use of combined ERC and pelvic phased-array coil for T2-weighted imaging and diffusion-weighted imaging provides superior sensitivity for the detection of PCa compared to an examination performed without the ERC.

PI-RADS Prostate Imaging - Reporting and Data System: 2015, Version 2

The Prostate Imaging - Reporting and Data System Version 2 (PI-RADS™ v2) is the product of an international collaboration of the American College of Radiology (ACR), European Society of Uroradiology (ESUR), and AdMetech Foundation. It is designed to promote global standardization and diminish variation in the acquisition, interpretation, and reporting of prostate multiparametric magnetic resonance imaging (mpMRI) examination, and it is based on the best available evidence and expert consensus opinion. It establishes minimum acceptable technical parameters for prostate mpMRI, simplifies and standardizes terminology and content of reports, and provides assessment categories that summarize levels of suspicion or risk of clinically significant prostate cancer that can be used to assist selection of patients for biopsies and management. It is intended to be used in routine clinical practice and also to facilitate data collection and outcome monitoring for research.

Five-point Likert scaling on MRI predicts clinically significant prostate carcinoma

Background

To clarify the relationship between the probability of prostate cancer scaled using a 5-point Likert system and the biological characteristics of corresponding tumor foci.

Methods

The present study involved 44 patients undergoing 3.0-Tesla multiparametric MRI before laparoscopic radical prostatectomy. Tracing based on pathological and MRI findings was performed. The relationship between the probability of cancer scaled using the 5-point Likert system and the biological characteristics of corresponding tumor foci was evaluated.

Results

A total of 102 tumor foci were identified histologically from the 44 specimens. Of the 102 tumors, 55 were assigned a score based on MRI findings (score 1: n = 3; score 2: n = 3; score 3: n = 16; score 4: n = 11 score 5: n = 22), while 47 were not pointed out on MRI. The tracing study revealed that the proportion of >0.5 cm³ tumors increased according to the upgrade of Likert scores (score 1 or 2: 33 %; score 3: 68.8 %; score 4 or 5: 90.9 %, χ² test, p < 0.0001). The proportion with a Gleason score >7 also increased from scale 2 to scale 5 (scale 2: 0 %; scale 3: 56.3 %; scale 4: 72.7 %; 5: 90.9 %, χ² test, p = 0.0001). On using score 3 or higher as the threshold of cancer detection on MRI, the detection rate markedly improved if the tumor volume exceeded 0.5 cm³ (<0.2 cm³: 10.3 %; 0.2-0.5 cm³: 25 %; 0.5-1.0 cm³: 66.7 %; 1.0 < cm³: 92.1 %).

Conclusions

Each Likert scale favobably reflected the corresponding tumor’s volume and Gleason score. Our observations show that “score 3 or higher” could be a useful threshold to predict clinically significant carcinoma when considering treatment options.

Does a cleansing enema improve image quality of 3T surface coil multiparametric prostate MRI?

PURPOSE

To assesses the utility of a preparatory enema in the interpretation of prostate multiparametric (MP) magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Under a waiver from the Institutional Review Board (IRB), 32 patients without bowel preparation and 28 patients who underwent a self-administered enema were imaged consecutively with 3T MP-MRI over 6 months. Two blinded radiologists independently assessed image quality on T2 -weighted (T2 W), trace b 1000 mm(2) /sec echo-planar (EPI) and apparent-diffusion coefficient (ADC) and assessed for motion/blur on T2 W and distortion/blur on EPI and ADC. Radiologists also quantified rectal stool and gas. A third blinded radiologist generated contrast curves from dynamic contrast-enhanced (DCE) data at six locations and measured the number of corrupted data points, defined as >10% aberrant signal intensity change. Subjective scores were compared using Wilcoxon sign rank test. Rectal contents were correlated to artifact using Spearman correlation. Contrast curves were evaluated with independent t-tests.

RESULTS

There was no difference in image quality on T2 W (P = 0.66-0.74), EPI (P = 0.13-0.36) or ADC (P = 0.49-0.59). There was less rectal stool in the enema group (P = 0.004) and amount of stool correlated with motion artifact on T2 W (r = 0.23, P = 0.02); however, there was no difference in motion artifact between groups (P = 0.47-0.94). Only a minority of patients in the non-enema group had moderate or large amounts of stool (16%) and none of these patients had severe or extensive artifact on T2 . There was less rectal gas in the enema group (P = 0.002); however, amount of gas did not correlate with distortion artifact on EPI or ADC (P = 0.17-0.41) and there was no difference in blur (P = 0.41-0.91) or distortion (P = 0.31-0.99) on EPI or ADC between groups. There was no difference in corrupted data points on DCE (P = 0.46).

CONCLUSION

In this study the use of a preparatory enema did not improve image quality or reduce artifact in prostate MP-MRI.

Multiparametric magnetic resonance imaging of the prostate: technical aspects and role in clinical management

The heterogeneity and largely indolent nature of prostate cancer require better tools to avoid overdetection of low-risk disease and improve diagnostic accuracy in high-risk patients. During the last 3 decades, magnetic resonance imaging (MRI) has evolved to become the most accurate imaging technique for prostate cancer detection and staging, with a promising role in risk stratification. Because each MRI technique has advantages and limitations, state of the art of the so-called multiparametric MRI of the prostate is achieved combining anatomical T2-weighted imaging integrated with other techniques in which image contrast is related to the pathophysiology of the disease, such as diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. After reviewing this article, readers will understand the clinical challenges in the management of patients with confirmed or suspected prostate cancer, when and how multiparametric MRI of the prostate can provide meaningful information, and how to perform and interpret it.

Multi-parametric (mp) MRI of prostatic ductal adenocarcinoma

BACKGROUND

Prostatic ductal adenocarcinoma (DCa) is an aggressive variant of conventional adenocarcinoma (CCa) with mixed DCa and CCa tumors comprising up to 5% of all prostate cancers. DCa may be underestimated on T2-weighted (T2W) MRI. This study assessed the mp-MRI appearance of DCa as compared with CCa.

METHODS

With research ethics board approval, we identified 38 patients who underwent mp-MRI (T2W, DWI, and DCE) and radical prostatectomy (RP) between 2012 and 2014. Eight DCa in 8 patients and 39 CCa tumor foci in 30 consecutive patients were identified. Tumor volume, apparent diffusion coefficient (ADC;10(-3) mm(2) /s), and time-signal intensity (SI) curves were calculated. Parametric data were compared using the Kruskal-Wallis test and univariate regression. Time-SI curves were compared using the chi-square test.

RESULTS

Tumor volumes were: 1.62(±1.02) for DCa, 1.03(±0.54) for Gleason 9, 0.88(±0.93) for Gleason 7/8, and 0.26(±0.14) mL for Gleason 6. There was no difference in size between DCa and Gleason 9 (P = 0.22); however, DCa were larger than Gleason 7/8 (P = 0.03) and Gleason 6 (P = 0.003) tumors. ADC values were: 0.789(±0.22) for DCa, 1.01(±0.19) for Gleason 9, 0.992(±0.23) for Gleason 7/8 and 1.389(±0.41) 10(-3) mm(2) /s for Gleason 6 tumors. There was no difference in ADC between DCa and Gleason 9 (P = 0.14) or Gleason 7/8 (P = 0.055) tumors. There was a difference in ADC for DCa and Gleason ≥7 CCa compared to Gleason 6 tumors, (P < 0.001 and P = 0.012). All DCa demonstrated type III time-SI curves. Gleason ≥ 7 tumors demonstrated type II/III curves. Gleason 6 tumors demonstrated Type I/II time-SI curves. There was no difference in curve type between groups, (P = 0.18).

CONCLUSION

Although DCa mimics Gleason score 3 + 3 = 6 tumor at T2W MRI; DCa resembles Gleason ≥7 CCa on mp-MRI.

Monte Carlo bias field correction in endorectal diffusion imaging

Prostate cancer is one of the leading causes of cancer death in the male population. The detection of prostate cancer using imaging has been challenging until recently. Multiparametric magnetic resonance imaging (MRI) has been shown to allow accurate localization of the cancers and can help direct biopsies to cancer foci, which is required to plan the treatment. The interpretation of MRI, however, requires a high level of expertise and review of large multiparametric datasets. An endorectal receiver coil is often used to improve signal-to-noise ratio and aid in detection of smaller cancer foci. Moreover, computed high b-value diffusion-weighted imaging show improved delineation of tumors but is subject to strong bias fields near the coil. Here, a nonparametric approach to bias field correction for endorectal diffusion imaging via Monte Carlo sampling is introduced. It will be shown that the delineation between the prostate gland and the background and intensity inhomogeneity may be improved using the proposed approach. High b-value generated results also show improved visualization of tumor regions. The results suggest that Monte Carlo bias correction may have potential as a preprocessing tool for endorectal diffusion images for the prostate cancer detection and localization or segmentation.

Influence of magnetic resonance imaging in the decision to preserve or resect neurovascular bundles at robotic assisted laparoscopic radical prostatectomy

PURPOSE

We evaluated the accuracy of preoperative multiparametric 3.0-T magnetic resonance imaging for local staging of prostate cancer and its influence in the decision to preserve neurovascular bundles at robotic assisted laparoscopic radical prostatectomy.

MATERIALS AND METHODS

The study included 353 patients who had confirmed prostate cancer and underwent preoperative magnetic resonance imaging and robotic assisted laparoscopic radical prostatectomy between 2008 and 2011. The extent of neurovascular bundle sparing was initially determined on the basis of the clinical information and the nerve sparing surgical plan was reevaluated after review of the magnetic resonance imaging report. The value of preoperative magnetic resonance imaging in the prediction of extracapsular extension and in the decision of surgical plan according to D'Amico risk classification was analyzed.

RESULTS

The magnetic resonance imaging performed correct staging, over staging and under staging in 261 (73.9%), 43 (12.2%), and 49 (13.9%) patients, respectively. After review of the magnetic resonance imaging reports, the initial surgical plan was not changed in 260 patients (74%) and was changed in 93 patients (26%). Robotic assisted laparoscopic radical prostatectomy was changed to a more preservable neurovascular bundle sparing procedure in 53 patients (57%) and changed to a more aggressive neurovascular bundle resecting procedure in 40 patients (43%). For the patients with a change to more conservative surgery, the appropriateness was 91%. The sensitivity of magnetic resonance imaging in predicting extracapsular extension showed a tendency to increase from low to high risk groups (33%, 46%, 80%, respectively, p <0.001). In intermediate and high risk groups, there was a surgical plan change in 40 patients (of 129, 31%) and 27 patients (of 67, 40%), respectively.

CONCLUSIONS

Preoperative magnetic resonance imaging significantly improves the decision making to preserve or resect the neurovascular bundle at robotic assisted laparoscopic radical prostatectomy, which lacks haptic feedback.

The role of magnetic resonance imaging in the diagnosis and management of prostate cancer

BACKGROUND

The diagnosis of prostate cancer has long been plagued by the absence of an imaging tool that reliably detects and localises significant tumours. Recent evidence suggests that multi-parametric MRI could improve the accuracy of diagnostic assessment in prostate cancer. This review serves as a background to a recent USANZ position statement. It aims to provide an overview of MRI techniques and to critically review the published literature on the clinical application of MRI in prostate cancer.

TECHNICAL ASPECTS

The combination of anatomical (T2-weighted) MRI with at least two of the three functional MRI parameters - which include diffusion-weighted imaging, dynamic contrast-enhanced imaging and spectroscopy - will detect greater than 90% of significant (moderate to high risk) tumours; however MRI is less reliable at detecting tumours that are small (<0.5 cc), low grade (Gleason score 6) or in the transitional zone. The higher anatomical resolution provided by 3-Tesla magnets and endorectal coils may improve the accuracy, particularly in primary tumour staging.

SCREENING

The use of mpMRI to determine which men with an elevated PSA should undergo biopsy is currently the subject of two large clinical trials in Australia. MRI should be used with caution in this setting and then only in centres with established uro-radiological expertise and quality control mechanisms in place. There is sufficient evidence to justify using MRI to determine the need for repeat biopsy and to guide areas in which to focus repeat biopsy.

IMAGE-DIRECTED BIOPSY

MRI-directed biopsy is an exciting concept supported by promising early results, but none of the three proposed techniques have so far been proven superior to standard biopsy protocols. Further evidence of superior accuracy and core-efficiency over standard biopsy is required, before their costs and complexities in use can be justified.

TREATMENT SELECTION AND PLANNING

When used for primary-tumour staging (T-staging), MRI has limited sensitivity for T3 disease, but its specificity of greater than 95% may be useful in men with intermediate-high risk disease to identify those with advanced T3 disease not suitable for nerve sparing or for surgery at all. MRI appears to be of value in planning dosimetry in men undergoing radiotherapy, and in guiding selection for and monitoring on active surveillance.

3-T in-bore MR-guided prostate biopsy based on a scoring system for target lesions characterization

BACKGROUND

To estimate potential malignant lesions within the prostate gland, the usage of a scoring system has recently been proposed by a European consensus meeting.

PURPOSE

To prospectively investigate a scoring system for functional prostate magnetic resonance imaging (MRI) using in-bore MR-guided prostate biopsy at 3-T.

MATERIAL AND METHODS

Prostate MRI examinations of 59 patients (between February 2011 and May 2012) with no known prostate cancer, elevated prostate specific antigen (PSA) level, and unsuspicious digital rectal examination were included in the study. In each patient up to three lesions were defined and scored using a 5-point scoring system for each MR sequence (T2-weighted images, diffusion-weighted imaging, dynamic contrast-enhanced imaging). Following MRI-guided in-bore biopsy these lesions were correlated to the histopathological findings.

RESULTS

A total number of 144 lesions were defined in 59 patients. In 28 patients (51 lesions) MR-guided in-bore biopsy was positive for tumor (Gleason grade 6 or higher). A cut-off limit of 10 or more points in summation of the individual scores of all three sequences was used, leading to a 90% sensitivity, 63% specificity, 58% positive predictive value, and 92% negative predictive value.

CONCLUSION

A simple 5-point scoring system of functional prostate MRI achieves excellent sensitivity and moderate specificity for directing 3-T-guided prostate biopsy relative to the histopathological findings.

MRI-targeted prostate biopsy: a review of technique and results

Multiparametric magnetic resonance imaging (mpMRI) is of interest for the diagnosis of clinically significant prostate cancer and mpMRI-targeted biopsies are being used increasingly in clinical practice. Target acquisition is performed using a range of magnet strengths and varying combinations of anatomical and functional sequences. Target identification at the time of biopsy can be carried out in the MRI scanner (in-bore biopsy) or, more commonly, the MRI-target is biopsied under ultrasonographic guidance. Many groups use cognitive or visual registration, whereby the biopsy target is identified on MRI and ultrasonography is subsequently used to direct the needle to the same location. Other groups use registration software to show prebiopsy MRI data on real-time ultrasonography. The reporting of histological results in MRI-targeted biopsy studies varies greatly. The most useful reports compare the detection of clinically significant disease in standard cores versus mpMRI-targeted cores in the same cohort of men, as recommended by the STAndards of Reporting for MRI-Targeted biopsy studies (START) consensus panel. Further evidence is needed before an mpMRI-targeted strategy can be recommended as the standard intervention for men at risk of prostate cancer.

[Functional MRI by general radiologists in prediction of side-specific extracapsular extension after radical prostatectomy: what value in daily practice?]

OBJECTIVE

To evaluate the performance of functional MRI (FMRI) performed by general radiologists (GR) in detection of side-specific extracapsular extension (SSECE) prostate cancer (PCa).

METHODS

We retrospectively analyzed 79 patients who underwent FMRI with pelvic phased array coil before radical prostatectomy (RP) performed at University Hospital (UH) of Nîmes. Twelve GR (including three from UH) interpreted the images during their daily practice. FMRI results were dichotomized as positive or negative and confronted to pathological reports for SSECE and side-specific seminal vesicle invasion (SSSVI), with calculation of diagnostic values. The influence of interval between biopsy and FMRI, diffusion-weighted sequence (DWS) and intensity of FMRI, on the diagnostic performance were assessed by Fisher's exact test.

RESULTS

A SSECE and a SSSVI were observed at FMRI and pathology respectively on 14 (8.8%) and 38 (24.1%) prostate lobes, and on six (3.8%) and seven (4.4%) prostate lobes. The sensitivity, specificity, positive and negative predictive values of FMRI for SSECE were respectively 24%, 96%, 64% and 80%; and for SSSVI were 14%, 97%, 17% and 96% respectively. The time between biopsy and FMRI, intensity of FMRI and DWS, did not influence the sensitivity and specificity of fMRI at Fisher test.

CONCLUSION

This study found that preoperative prostate FMRI performed by GR has good specificity but poor sensitivity in predicting SSECE on pathological reports.

Effects of post biopsy digital rectal compression on improving prostate cancer staging using magnetic resonance imaging in localized prostate cancer

PURPOSE

To evaluate the effectiveness of digital rectal-compression immediately after transrectal prostate biopsy (P-bx) for improving the accuracy of prostate cancer (PCa) staging.

MATERIALS AND METHODS

Between July 2008 and June 2010, 94 consecutive patients who had a radical prostatectomy were included in our retrospective analysis. The exclusion criteria included a history of previous P-bx and surgery, a biopsy performed in another hospital, a number of biopsy cores different from 12, or a condition interfering with bleeding assessment. The subjects were divided into two groups, compression and non-compression. All enrolled patients took magnetic resonance imaging (MRI) for PCa staging.

RESULTS

The compression and non-compression groups were comparable with respect to several baseline characteristics. However, the total hemorrhage score of intraprostatic bleeding was significantly different between the groups, even with adjustment for the time from biopsy to MRI (compression:15.4 ± 2.32, non-compression: 24.9 ± 2.43, p<0.001). The intra-prostatic cancer location matching rate was higher in the compression group (78.0%) than in the non-compression group (70.2%) (p = 0.011). Overall accuracy of staging in compression and non-compression groups was 84.7% and 77.3%, respectively.

CONCLUSION

Our results demonstrate that digital rectal compression performed immediately after prostate biopsy to reduce intraprostatic hemorrhage improves the accuracy for detection of PCa using MRI.