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

Pathologic prostate cancer grade concordance among high-resolution micro-ultrasound, systematic transrectal ultrasound and MRI fusion biopsy

BACKGROUND AND OBJECTIVE

Comparative studies among biopsy strategies have not been conducted evaluating pathologic concordance at radical prostatectomy(RP), especially with novel micro-ultrasound (micro-US) image-guided biopsy.

METHODS

A retrospective study among patients with PCa who underwent RP following TRUS, MRI-TRUS fusion, microUS, or MRI-microUS fusion biopsy in a multi-site single institution. We compared GG-upgrade from biopsy to RP based on highest GG in any biopsy core and examined clinical/pathologic factors associated with pathologic upgrading using descriptive statistics, and multivariable logistic-regression analysis.

RESULTS

429 patients between 1/2021 and 6/2023 including 10 (25.6%) who underwent systematic TRUS, 237 (55.2%) MRI-TRUS, 67 (15.6%) MRI-microUS and 15 (3.5%) micoUS-alone biopsy prior to RP. 78 (18.2%) were upgraded on final pathology (TRUS 31 (28.2%), MRI-TRUS 31 (13.1%), MRI-microUS 10 (14.9%), microUS: 6 (40%)) and 99 downgraded. 14 (3.5%) experienced a major upgrade (≥2 GG increase). On multivariable-analysis both MRI-TRUS (odds ratio, OR: 0.31,95% CI:0.17-0.56, P < 0.001) and MRI-microUS (OR: 0.43,95%CI: 0.19-0.98, P = 0.044) were associated with lower odds pathological-upgrade compared with TRUS biopsy alone. No significant differences in the odds of upgrade between TRUS and microUS alone (P > 0.05), or between MRI-microUS and MRI-TRUS(P = 0.696) on pairwise comparisons. MRI-microUS was associated with lower upgrade compared with microUS (OR: 0.26,95% CI:0.08-0.90, P = 0.034). No difference among the biopsy strategies in pathologic downgrading or overall GG concordance. Limitations include retrospective analysis, inter-clinician experience and lesion selection in varying biopsy techniques.

CONCLUSION

Both MRI-microUS and MRI-TRUS fusion were associated with similarly improved GG concordance compared with TRUS biopsy. No significant differences between microUS-alone and TRUS or between MRI-microUS and MRI-TRUS fusion approaches, may suggest similar accuracy performance for disease sampling.

WHAT DOES THE STUDY ADD

To our knowledge, this is the first study to investigate GG concordance based on type of biopsy, especially microUS related GG upgrading after RP. In a moderately sized cohort this is the first to investigate pathologic concordance in MRI-microUS fusion compared to MRI-TRUS fusion biopsy. Our study may help urologists in counseling patients after biopsy and choosing the ideal image guided biopsy technique, however randomized controlled trials are needed to validate our results.

PATIENT SUMMARY

We performed a study to see if the type of prostate biopsy, including use of MRI assistance as well as a new image-guided biopsy using a more advanced ultrasound, was better able to identify the aggressiveness of prostate cancer patients had. We found that the new biopsy type when fused with MRI and the existing MRI-guided biopsy type were similar in predicting the type of prostate cancer found at prostate surgery. These were both more accurate than the conventional ultrasound only biopsy.

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.

A Novel Three-Channel Endorectal Coil for Prostate Magnetic Resonance Imaging at 3T

OBJECTIVE

The purpose of this work is to develop a 3-channel endorectal coil (ERC-3C) structure to obtain higher signal-to-noise (SNR) and better parallel imaging performance for prostate magnetic resonance imaging (MRI) at 3T.

METHODS

The coil performance was validated by in vivo studies and the SNR, g-factor, and diffusion-weighted imaging (DWI) were compared. A 2-channel endorectal coil (ERC-2C) with two orthogonal loops and a 12-channel external surface coil were employed for comparison.

RESULTS

Compared with the ERC-2C with a quadrature configuration and the external 12-channel coil array, the proposed ERC-3C improved SNR performance by 23.9% and 428.9%, respectively. The improved SNR enables the ERC-3C to produce spatial high-resolution images of 0.24 mm × 0.24 mm × 2 mm (0.1152 μL) in the prostate area within 9 minutes.

CONCLUSION

We developed an ERC-3C and validated its performance through in vivo MR imaging experiments.

SIGNIFICANCE

The results demonstrated the feasibility of an ERC with more than two channels and that a higher SNR can be achieved using the ERC-3C compared with an orthogonal ERC-2C of the same coverage.

Use of Imaging and Biopsy in Prostate Cancer Diagnosis: A Survey From the Asian Prostate Imaging Working Group

OBJECTIVE

To elucidate the use of radiological studies, including nuclear medicine, and biopsy for the diagnosis and staging of prostate cancer (PCA) in clinical practice and understand the current status of PCA in Asian countries via an international survey.

MATERIALS AND METHODS

The Asian Prostate Imaging Working Group designed a survey questionnaire with four domains focused on prostate magnetic resonance imaging (MRI), other prostate imaging, prostate biopsy, and PCA backgrounds. The questionnaire was sent to 111 members of professional affiliations in Korea, Japan, Singapore, and Taiwan who were representatives of their working hospitals, and their responses were analyzed.

RESULTS

This survey had a response rate of 97.3% (108/111). The rates of using 3T scanners, antispasmodic agents, laxative drugs, and prostate imaging-reporting and data system reporting for prostate MRI were 21.6%-78.9%, 22.2%-84.2%, 2.3%-26.3%, and 59.5%-100%, respectively. Respondents reported using the highest b-values of 800-2000 sec/mm² and fields of view of 9-30 cm. The prostate MRI examinations per month ranged from 1 to 600, and they were most commonly indicated for biopsy-naïve patients suspected of PCA in Japan and Singapore and staging of proven PCA in Korea and Taiwan. The most commonly used radiotracers for prostate positron emission tomography are prostate-specific membrane antigen in Singapore and fluorodeoxyglucose in three other countries. The most common timing for prostate MRI was before biopsy (29.9%). Prostate-targeted biopsies were performed in 63.8% of hospitals, usually by MRI-ultrasound fusion approach. The most common presentation was localized PCA in all four countries, and it was usually treated with radical prostatectomy.

CONCLUSION

This survey showed the diverse technical details and the availability of imaging and biopsy in the evaluation of PCA. This suggests the need for an educational program for Asian radiologists to promote standardized evidence-based imaging approaches for the diagnosis and staging of PCA.