Related Experiment Video
Updated: May 1, 2026
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Geometric distortion in diffusion-weighted MR imaging of the prostate-contributing factors and strategies for
Francisco Donato1, Daniel N Costa1, Qing Yuan1
1Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9061.
Rationale And Objectives:
Image distortion on diffusion-weighted imaging (DWI) of the prostate in 3T endorectal magnetic resonance imaging (MRI) examinations is common. The aim of this study was to determine the degree of distortion on DWI using a state-of-the-art clinical protocol and to explore the main contributors to geometric distortion.
Materials And Methods:
Forty consecutive patients underwent 3T MRI of the prostate with an endorectal coil filled with air (n = 20) or barium sulfate (n = 20). Distortion was measured as the maximum displacement of the outer boundary of the prostate on DWI relative to T2-weighted imaging. The effects of phase-encoding direction, receiver bandwidth, and parallel imaging were then assessed in a prostate phantom on two MRI scanners from different manufacturers.
Results:
There was no statistical difference in the mean displacement of the prostate on DWI between the air cohort (1.8 ± 1.2 mm, range 0-4.2 mm) and barium cohort (1.8 ± 2.2 mm, range 0-9 mm). Displacement of the prostate was observed in the phase-encoding direction. Phantom experiments demonstrated a horizontal displacement of 6.0 mm in the phase-encoding direction, which decreased with the use of parallel imaging and higher bandwidth. Geometric distortion was similar for all b values and across manufacturers.
Conclusions:
Geometric distortion on DWI of the prostate is common in the phase-encoding direction and does not improve with inflating the coil with barium sulfate. Strategies to reduce this artifact include the use of higher bandwidth and accelerated imaging. Correction of this phenomenon should improve localization of prostate cancer, particularly important for targeted prostate biopsies or focal therapies.
Insights
Image distortion on prostate diffusion-weighted imaging (DWI) is common. Using higher bandwidth and accelerated imaging can reduce this geometric distortion, improving cancer localization for biopsies and therapies.
Area of Science:
- Radiology
- Medical Imaging
- Oncology
Background:
- Diffusion-weighted imaging (DWI) in 3T endorectal MRI of the prostate frequently exhibits image distortion.
- Geometric distortion can impact the accuracy of prostate cancer localization.
Purpose of the Study:
- To quantify image distortion in prostate DWI using a current clinical protocol.
- To identify key factors contributing to geometric distortion.
Main Methods:
- Compared distortion in 40 patients using endorectal coils filled with air versus barium sulfate.
- Assessed distortion by measuring prostate boundary displacement on DWI relative to T2-weighted imaging.
- Evaluated effects of phase-encoding direction, receiver bandwidth, and parallel imaging in a prostate phantom.
Main Results:
- No significant difference in mean prostate displacement between air (1.8 ± 1.2 mm) and barium (1.8 ± 2.2 mm) cohorts.
- Prostate displacement occurred primarily in the phase-encoding direction.
- Phantom experiments showed reduced displacement with parallel imaging and higher bandwidth.
Conclusions:
- Geometric distortion in prostate DWI is prevalent, particularly in the phase-encoding direction, and is not mitigated by barium sulfate-filled coils.
- Higher bandwidth and accelerated imaging are effective strategies to reduce distortion.
- Reducing this artifact is crucial for accurate prostate cancer localization in biopsies and focal therapies.
