A standardized method to measure the membranous urethral length (MUL) on MRI of the prostate with high inter- and intra-observer agreement

Veerman, Hans; Hagens, Marinus J.; Hoeks, Caroline; Poel, Henk G. van der; Leeuwen, Pim J. van; Vis, André N.; Heijmink, Stijn; Schoots, Ivo G.; Haan, Margriet C. de; Boellaard, Thierry N.

doi:10.1007/s00330-022-09320-2

Cited by 9 publications

(9 citation statements)

References 29 publications

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“…In the second session, the superior point was consistently positioned at the inferior border of the prostate due to the DL-generated segmentations, which contributed to increased consistency as indicated by the AI-aided measurements. This definition of the MUL measurement was comparable to previous studies [ 3 , 6 , 7 ].…”

Section: Discussionsupporting

confidence: 89%

“…Both coronal and sagittal MUL measurements demonstrated improved interobserver agreement, with the coronal MUL increasing from an ICC value of 0.69 (95% CI 0.51–0.82) to 0.90 (95% CI 0.82–0.94) and the sagittal MUL improving from 0.64 (95% CI 0.28–0.83) to 0.91 (95% CI 0.84–0.95), indicating a shift from substantial to almost perfect agreement. Veerman et al [ 7 ] reported a comparable ICC value of 0.63 (95% CI 0.28–0.81) for the sagittal MUL measurements on raw images but achieved an improved ICC value of 0.84 (95% CI 0.66–0.91) with the implementation of consistent anatomical definitions. In our study, DL-generated segmentations resulted in a higher ICC value of 0.91 (95% CI 0.84–0.95), demonstrating the potential of AI to further improve consistency in the measurements.…”

Section: Discussionmentioning

confidence: 99%

“…The MUL measurements in our study were comparable with Kim et al [ 3 ], who reported mean values of 14.6 mm in the coronal direction and 14.2 mm in the sagittal direction. Veerman et al [ 7 ] found higher MUL measurements of 17 mm, which could potentially be attributed to the inclusion of patients with higher MUL values since the introduction of a risk prediction model of urinary incontinence in their institution [ 15 ]. LAM measurements were comparable to the findings of Sadahira et al [ 16 ] but higher than the measurements reported by Muñoz-Calahorro et al [ 6 ], which ranged between 4.22 and 6.87 mm.…”

Section: Discussionmentioning

confidence: 99%

“…However, manual assessment is prone to considerable interobserver disagreement, with varying intra-class correlation coefficient (ICC) values from 0.37 to 0.57 [ 6 ]. To improve interobserver agreement, Veerman et al [ 7 ] investigated the use of standardized anatomical landmarks for MUL measurements, resulting in improved interobserver agreement with ICC values ranging from 0.63 to 0.84 among three radiologists within a single center.…”

Section: Introductionmentioning

confidence: 99%

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Automated pelvic MRI measurements associated with urinary incontinence for prostate cancer patients undergoing radical prostatectomy

van den Berg,

Spaans,

Wessels

et al. 2024

Eur Radiol Exp

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Background Pelvic morphological parameters on magnetic resonance imaging (MRI), such as the membranous urethral length (MUL), can predict urinary incontinence after radical prostatectomy but are prone to interobserver disagreement. Our objective was to improve interobserver agreement among radiologists in measuring pelvic parameters using deep learning (DL)-based segmentation of pelvic structures on MRI scans. Methods Preoperative MRI was collected from 167 prostate cancer patients undergoing radical prostatectomy within our regional multicentric cohort. Two DL networks (nnU-Net) were trained on coronal and sagittal scans and evaluated on a test cohort using an 80/20% train-test split. Pelvic parameters were manually measured by three abdominal radiologists on raw MRI images and with the use of DL-generated segmentations. Automated measurements were also performed for the pelvic parameters. Interobserver agreement was evaluated using the intraclass correlation coefficient (ICC) and the Bland–Altman plot. Results The DL models achieved median Dice similarity coefficient (DSC) values of 0.85–0.97 for coronal structures and 0.87–0.98 for sagittal structures. When radiologists used DL-generated segmentations of pelvic structures, the interobserver agreement for sagittal MUL improved from 0.64 (95% confidence interval 0.28–0.83) to 0.91 (95% CI 0.84–0.95). Furthermore, there was an increase in ICC values for the obturator internus muscle from 0.74 (95% CI 0.42–0.87) to 0.86 (95% CI 0.75–0.92) and for the levator ani muscle from 0.40 (95% CI 0.05–0.66) to 0.61 (95% CI 0.31–0.78). Conclusions DL-based automated segmentation of pelvic structures improved interobserver agreement in measuring pelvic parameters on preoperative MRI scans. Relevance statement The implementation of deep learning segmentations allows for more consistent measurements of pelvic parameters by radiologists. Standardized measurements are crucial for incorporating these parameters into urinary continence prediction models. Key points • DL-generated segmentations improve interobserver agreement for pelvic measurements among radiologists. • Membranous urethral length measurement improved from substantial to almost perfect agreement. • Artificial intelligence enhances objective pelvic parameter assessment for continence prediction models. Graphical Abstract

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Automated pelvic MRI measurements associated with urinary incontinence for prostate cancer patients undergoing radical prostatectomy

van den Berg,

Spaans,

Wessels

et al. 2024

Eur Radiol Exp

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“…For example, in two studies performed in the same country, the difference between median MUL was 10 mm [ 20 , 21 ]. Our group performed an agreement study and found high intra- and inter-observer agreement using well-defined landmarks and standardized measurement technique [ 22 ]. Although the MUL is often measured by MRI, MUL can also be measured by using ultrasound [ 23 , 24 ].…”

Section: Anatomical Parameters To Predict Urinary Continence After Ra...mentioning

confidence: 99%

Prostate MRI for Improving Personalized Risk Prediction of Incontinence and Surgical Planning: The Role of Membranous Urethral Length Measurements and the Use of 3D Models

Boellaard

Hagens

Veerman

et al. 2023

Life

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Prostate MRI has an important role in prostate cancer diagnosis and treatment, including detection, the targeting of prostate biopsies, staging and guiding radiotherapy and active surveillance. However, there are other ‘’less well-known’’ applications which are being studied and frequently used in our highly specialized medical center. In this review, we focus on two research topics that lie within the expertise of this study group: (1) anatomical parameters predicting the risk of urinary incontinence after radical prostatectomy, allowing more personalized shared decision-making, with special emphasis on the membranous urethral length (MUL); (2) the use of three-dimensional models to help the surgical planning. These models may be used for training, patient counselling, personalized estimation of nerve sparing and extracapsular extension and may help to achieve negative surgical margins and undetectable postoperative PSA values.

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Membranous urethral length measurement on preoperative MRI to predict incontinence after radical prostatectomy: a literature review towards a proposal for measurement standardization

Boellaard,

van Dijk-de Haan,

Heijmink

et al. 2023

Eur Radiol

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Objectives To investigate the membranous urethral length (MUL) measurement and its interobserver agreement, and propose literature-based recommendations to standardize MUL measurement for increasing interobserver agreement. MUL measurements based on prostate MRI scans, for urinary incontinence risk assessment before radical prostatectomy (RP), may influence treatment decision-making in men with localised prostate cancer. Before implementation in clinical practise, MRI-based MUL measurements need standardization to improve observer agreement. Methods Online libraries were searched up to August 5, 2022, on MUL measurements. Two reviewers performed article selection and critical appraisal. Papers reporting on preoperative MUL measurements and urinary continence correlation were selected. Extracted information included measuring procedures, MRI sequences, population mean/median values, and observer agreement. Results Fifty papers were included. Studies that specified the MRI sequence used T2-weighted images and used either coronal images (n = 13), sagittal images (n = 18), or both (n = 12) for MUL measurements. ‘Prostatic apex’ was the most common description of the proximal membranous urethra landmark and ‘level/entry of the urethra into the penile bulb’ was the most common description of the distal landmark. Population mean (median) MUL value range was 10.4–17.1 mm (7.3–17.3 mm), suggesting either population or measurement differences. Detailed measurement technique descriptions for reproducibility were lacking. Recommendations on MRI-based MUL measurement were formulated by using anatomical landmarks and detailed descriptions and illustrations. Conclusions In order to improve on measurement variability, a literature-based measuring method of the MUL was proposed, supported by several illustrative case studies, in an attempt to standardize MRI-based MUL measurements for appropriate urinary incontinence risk preoperatively. Clinical relevance statement Implementation of MUL measurements into clinical practise for personalized post-prostatectomy continence prediction is hampered by lack of standardization and suboptimal interobserver agreement. Our proposed standardized MUL measurement aims to facilitate standardization and to improve the interobserver agreement. Key Points • Variable approaches for membranous urethral length measurement are being used, without detailed description and with substantial differences in length of the membranous urethra, hampering standardization. • Limited interobserver agreement for membranous urethral length measurement was observed in several studies, while preoperative incontinence risk assessment necessitates high interobserver agreement. • Literature-based recommendations are proposed to standardize MRI-based membranous urethral length measurement for increasing interobserver agreement and improving preoperative incontinence risk assessment, using anatomical landmarks on sagittal T2-weighted images.

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A standardized method to measure the membranous urethral length (MUL) on MRI of the prostate with high inter- and intra-observer agreement

Cited by 9 publications

References 29 publications

Automated pelvic MRI measurements associated with urinary incontinence for prostate cancer patients undergoing radical prostatectomy

Automated pelvic MRI measurements associated with urinary incontinence for prostate cancer patients undergoing radical prostatectomy

Prostate MRI for Improving Personalized Risk Prediction of Incontinence and Surgical Planning: The Role of Membranous Urethral Length Measurements and the Use of 3D Models

Membranous urethral length measurement on preoperative MRI to predict incontinence after radical prostatectomy: a literature review towards a proposal for measurement standardization

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