Quantifying the effect of biopsy lateral decubitus patient positioning compared to supine prostate magnetic resonance image scanning on prostate translocation and distortion

  • Žiga Snoj
  • Leonardo Rundo
  • Andrew B. Gill
  • Tristan Barrett
Keywords: Prostate translocation, Prostate distortion, Positional change, MRI, Biopsy lateral decubitus

Abstract

Introduction: More than a quarter of tumors are missed by magnetic resonance imaging/ultrasound (MRI/US) fusion-guided biopsy, the majority due to software-based misregistration. Transrectal approaches to biopsy are typically performed in the lateral decubitus position; conversely, diagnostic MRI is performed with the patient lying supine. Any position-related difference in prostate location or gland deformation could potentially exacerbate misregistration at subsequent biopsy.

Methods: Fifteen healthy male volunteers (mean age 35.9 years, range 27–53) were included in this prospective, institutional review board-approved study. Each volunteer had an MRI performed in the supine position, followed by the second in the lateral decubitus position (mimicking a typical biopsy position). MRI images were co-registered and analyzed in order to assess prostate translocation and distortion.

Results: Whole prostate translocation of ≥5 mm was observed in 20% of patients and of ≥3 mm in 60% of patients. When dividing the prostate into prostatic sectors, the prostatic base demonstrated the largest positional difference. When plotting the translocation directions with relative volume difference, there was a moderate negative correlation trend in the latero-lateral direction. Only minimal distortion was observed, with similar distortion among all prostatic sectors.

Conclusions: Positional change affects the prostate translocation, however, the effect on prostate distortion appears to be negligible. Prostate translocation in latero-lateral direction can be minimized with larger bladder volumes. Prostate translocation needs to be considered alongside software misregistration error; however, positional change should not affect software registration of MRI/US fusion-guided prostate biopsy.

Published
2020-03-30
How to Cite
Snoj, Žiga, Rundo, L., Gill, A. B., & Barrett, T. (2020). Quantifying the effect of biopsy lateral decubitus patient positioning compared to supine prostate magnetic resonance image scanning on prostate translocation and distortion. Canadian Urological Association Journal, 14(9), E445-52. https://doi.org/10.5489/cuaj.6298
Section
Original Research