Preliminary Phantom Study of Low-Field MRI for Office-Based Prostate Biopsy

Overview

This study evaluates the navigation accuracy of a novel low-field (0.066 T) office-based MRI system designed for MR-guided transperineal prostate biopsy. The system demonstrated the ability to localize biopsy targets within a 5 mm accuracy threshold, which aligns with clinically significant prostate cancer lesion dimensions.

Background

Prostate cancer is the second most common cancer among men in the US, with early detection critical to improving survival outcomes. Traditional biopsy methods, such as transrectal ultrasound-guided biopsy (TRUS), have limitations including incomplete sampling and infection risks. MRI-guided biopsy techniques improve lesion targeting but often require complex infrastructure. The Promaxo low-field MRI system offers a compact, office-based solution for direct MR-guided transperineal prostate biopsy, potentially overcoming barriers of conventional approaches.

Data Highlights

The study used a commercially available transperineal grid template with 5 mm spacing and fiducial markers for calibration. The acceptance criterion for navigation accuracy was set at 5 mm, corresponding to the radius of a clinically significant tumor volume (0.5 cm³). The system's navigation software enabled planning and directing biopsy needles through the template with real-time image guidance.

Key Findings

• The low-field MRI system produced transverse, sagittal, and coronal images sufficient for prostate visualization in an office setting.
• Template calibration using fiducial markers allowed accurate registration of the biopsy grid relative to the prostate anatomy.
• The navigation accuracy met the 5 mm acceptance criterion, suitable for targeting clinically significant prostate cancer lesions.
• The system's compact design and low magnetic field enable safe use without facility upgrades or cryogens.
• The transperineal approach facilitated by the system reduces infection risks associated with transrectal biopsies.

Clinical Implications

This low-field MRI system enables precise MR-guided transperineal prostate biopsies in an office environment, potentially improving cancer detection rates while minimizing infection risks. Its ease of use and minimal infrastructure requirements may facilitate wider adoption of targeted prostate biopsy techniques outside of specialized imaging centers.

Conclusion

The preliminary phantom investigations demonstrate that the office-based low-field MRI system can achieve clinically relevant navigation accuracy for prostate biopsy guidance. This technology holds promise for enhancing prostate cancer diagnosis in routine urology practice.

References

1. Siegel et al. 2020 -- Cancer statistics, 2020
2. SEER Cancer Statistics Review -- Prostate Cancer Survival
3. NCCN Guidelines -- Prostate Cancer Early Detection
4. Hu et al. -- MRI-Ultrasound Fusion Registration Errors
5. PI-RADS v2.1 -- Prostate Imaging Reporting and Data System
6. Promaxo MRI System -- Office-Based Low-Field MRI for Prostate Biopsy