Prostate cancer is one of the most frequently diagnosed cancers among men and remains a major health burden globally. Magnetic resonance imaging (MRI) has become a pivotal tool in the early detection and diagnosis of clinically significant prostate cancer, with international guidelines now recommending MRI prior to bopsy. This shift in diagnostic pathways has been supported by several large clinical trials demonstrating that MRI can reduce overdiagnosis and unnecessary biopsies. However, the practical application of MRI in daily clinical settings has revealed inconsistencies in image quality, potentially limiting its diagnostic utility. A national study in the Netherlands sought to evaluate the current quality of prostate MRI, examine adherence to PI-RADSv2.1 technical recommendations and identify additional factors that may influence image quality.
Adherence to PI-RADSv2.1 Technical Recommendations
The study examined the compliance of Dutch hospitals with PI-RADSv2.1 technical recommendations through a national survey. Out of 68 invited institutions, 58 responded, and 48 of these performed prostate MRI for cancer detection. Compliance with the technical guidelines was generally high, with a median adherence of 74% among survey respondents and 78% among centres that provided image data. However, variation was evident. For example, while 98% of centres included additional sagittal and/or coronal T2-weighted imaging, only 6.8% met the recommended in-plane resolution in the frequency direction of ≤ 0.4 mm. This specific recommendation may present practical challenges, particularly in balancing resolution with signal-to-noise ratio on 1.5 Tesla scanners. Other areas of low compliance included the presence of interslice gaps and consistent imaging planes across sequences. These findings suggest that while Dutch centres largely follow established technical guidelines, there are several parameters where full adherence is either difficult to achieve or deprioritised.
Image Quality Evaluation Across Dutch Hospitals
To assess actual image quality, a reader study was conducted using 252 MRI examinations submitted by 13 hospitals. Each scan was evaluated independently by experienced prostate radiologists using the PI-QUALv2 scoring system. The results revealed that 30.9% of multiparametric MRI (mp-MRI) and 50.6% of biparametric MRI (bp-MRI) scans were of inadequate quality. Even when mp-MRI scans were assessed without the dynamic contrast-enhanced (DCE) sequence, the percentage of inadequate scans increased, suggesting that the inclusion of DCE may compensate for quality deficiencies in T2-weighted or diffusion-weighted images. The mean quality scores were generally higher for mp-MRI compared to bp-MRI, with the latter particularly affected by lower quality in both anatomical and functional sequences. These results are concerning, particularly for centres using the shorter bp-MRI protocol without maintaining high image quality, potentially undermining the diagnostic benefits of MRI in prostate cancer detection.
Factors Influencing Prostate MRI Quality
The study explored several variables that may influence image quality, beyond the scope of PI-RADSv2.1 recommendations. Hardware emerged as a key factor. Scans performed on 3 Tesla MRI systems consistently achieved higher quality scores than those on 1.5 Tesla systems, particularly in T2-weighted and diffusion-weighted sequences. The type of coil also influenced contrast in diffusion-weighted imaging, with body coils performing better than pelvic coils, possibly due to differences in channel configuration.
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Technical parameters such as the direction of phase encoding and slice thickness also played a role. Sagittal T2-weighted images acquired using craniocaudal encoding provided better anatomical delineation than those using an anterior-posterior direction. Furthermore, interslice gaps and resolution had measurable effects on signal-to-noise ratio and structural clarity.
Patient preparation was another area where image quality could be influenced. Centres that instructed patients to refrain from ejaculation before the scan or used antispasmodic agents generally achieved better image quality. Similarly, the use of rectal catheters, although rare, appeared to reduce motion artefacts and improve the clarity of diffusion-weighted images. Education of personnel also made a significant difference. Centres where radiologists had completed dedicated training courses in prostate MRI demonstrated higher image quality scores, suggesting that ongoing education is essential for maintaining standards.
The study highlighted both strengths and weaknesses in the current state of prostate MRI in the Netherlands. While overall compliance with PI-RADSv2.1 technical recommendations is relatively high, a substantial proportion of scans still fall short of acceptable image quality. The findings suggest that following technical standards alone is not sufficient to ensure high-quality imaging. A more comprehensive approach that includes equipment optimisation, patient preparation and personnel training is essential. By addressing these additional factors, healthcare institutions can enhance the effectiveness of prostate MRI as a diagnostic tool and ensure more reliable pathways for prostate cancer detection.
Source: Insights into Imaging
Image Credit: Freepik
