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Updated: Jul 19, 2026
06:08
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Prostate volume determination: differential volume measurements comparing CT and TRUS
Karl Mikael Kälkner1, Gregory Kubicek, Josef Nilsson
1Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden. karl.kalkner@karolinska.se
Summary
Computerized tomography (CT) measures prostate volumes about 30% larger than transrectal ultrasound (TRUS) methods. This difference, likely due to CT
Area of Science:
- Radiology
- Oncology
- Medical Imaging
Background:
- Accurate prostate volume measurement is crucial for radiotherapy planning.
- Different imaging modalities may yield varying prostate volume assessments.
Purpose of the Study:
- To compare prostate volume measurements obtained via computerized tomography (CT), step-section transrectal ultrasound (TRUS-step), and ellipsoid-formula transrectal ultrasound (TRUS-ellipsoid).
Main Methods:
- Retrospective analysis of prostate volumes from 31 localized prostate cancer patients undergoing radiotherapy.
- Measurements were obtained using CT, TRUS-step, and TRUS-ellipsoid as per clinical routine for dose planning.
Main Results:
- Average prostate volumes: CT (34 cc), TRUS-step (28 cc), TRUS-ellipsoid (24 cc).
- CT defined prostate lengths were longer (4.5 cm) compared to TRUS-step and TRUS-ellipsoid (3.6 cm).
- CT volumes were approximately 30% larger than TRUS-step volumes.
Conclusions:
- Computerized tomography (CT) overestimates prostate volume compared to transrectal ultrasound (TRUS) techniques.
- Uncertainty in defining the prostate apex on CT may contribute to length and volume discrepancies.
- Awareness of imaging modality differences is essential for accurate radiotherapy target definition.
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