Abstract
Prostate-specific antigen (PSA) density is a key determinant in biopsy decision-making, but its calculation usually depends on MRI-based prostate volumetry, which is both reader-dependent and costly. Micro-ultrasound (microUS) provides high-resolution imaging of the entire prostate, enabling bedside gland volumetry and offering a practical MRI-free alternative for PSA-density assessment prior to biopsy. However, free-hand microUS sweeps are uncalibrated through-plane, meaning frame counts reflect hand speed rather than true anatomical length. In this study of 455 men, we introduce an automated 2D nnU-Net pipeline with two key design choices to overcome this: (1) using the mean cross-sectional area rather than the sum to bypass hand-speed variance, and (2) applying a geometric filter to remove truncated or irregular sweeps. This mean-area estimator improved volume agreement with MRI compared to the naive sum (Concordance Correlation Coefficient [CCC] 0.83 vs. 0.58, p < 0.001). The geometric filter further tightened within-patient agreement and abstained on large, unmeasurable glands. Clinically, the microUS-derived PSA-density agreed with MRI in 85% of cases, matching standard MRI inter-reader variability. In predicting clinically significant prostate cancer, the microUS volume was equivalent to MRI within a pre-specified ±0.05 AUROC margin (0.76 vs. 0.75; two one-sided tests [TOST] p = 0.002). We demonstrate that automated microUS volumetry is a reproducible, mathematically robust, MRI-free alternative for risk stratification
Links to Paper and Supplementary Materials
Main Paper (Open Access Version): https://papers.miccai.org/miccai-2026-sat/paper/ASMUS_061.pdf
SharedIt Link: Not yet available
SpringerLink (DOI): Not yet available
Supplementary Material: Not Submitted
Link to Open Review
Open Review Page: https://openreview.net/forum?id=SNIcbmxRWX
BibTex
@InProceedings{WinNek_Automated_MICCAISAT2026,
author = { Winter, Nektarios AND Kovacs, Balint AND Mangold, Maurin Helen AND Michel, Maurice Stephan AND Haney-Aubert, Caelan Max AND Kowalewski, Karl-Friedrich},
title = { { Automated Micro-Ultrasound Prostate Volume for MRI-Free PSA-Density: Reproducibility and Agreement with MRI } },
booktitle = {Medical Image Computing and Computer Assisted Intervention -- MICCAI 2026 Workshops and Challenges},
year = {2026},
publisher = {Springer Nature Switzerland},
volume = {LNCS 17276},
month = {pending},
page = {pending}
}