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Published on: April 9, 2019
Novel technique for characterizing prostate cancer utilizing MRI restriction spectrum imaging: proof of principle and
R A Rakow-Penner1, N S White1, J K Parsons2
1Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
Background:
Standard magnetic resonance imaging (MRI) of the prostate lacks sensitivity in the diagnosis and staging of prostate cancer (PCa). To improve the operating characteristics of prostate MRI in the detection and characterization of PCa, we developed a novel, enhanced MRI diffusion technique using restriction spectrum imaging (RSI-MRI).
Methods:
We compared the efficacy of our novel RSI-MRI technique with standard MRI for detecting extraprostatic extension (EPE) among 28 PCa patients who underwent MRI and RSI-MRI prior to radical prostatectomy, 10 with histologically proven pT3 disease. RSI cellularity maps isolating the restricted isotropic water fraction were reconstructed based on all b-values and then standardized across the sample with z-score maps. Distortion correction of the RSI maps was performed using the alternating phase-encode technique.
Results:
27 patients were evaluated, excluding one patient where distortion could not be performed. Preoperative standard MRI correctly identified extraprostatic the extension in two of the nine pT3 (22%) patients, whereas RSI-MRI identified EPE in eight of nine (89%) patients. RSI-MRI correctly identified pT2 disease in the remaining 18 patients.
Conclusions:
In this proof of principle study, we conclude that our novel RSI-MRI technology is feasible and shows promise for substantially improving PCa imaging. Further translational studies of prostate RSI-MRI in the diagnosis and staging of PCa are indicated.
Insights
Restriction spectrum imaging MRI (RSI-MRI) significantly improves prostate cancer detection and staging. This novel technique shows promise for enhanced prostate cancer imaging, outperforming standard MRI in identifying extraprostatic extension.
Area of Science:
- Radiology
- Oncology
- Medical Imaging
Background:
- Standard prostate MRI has limited sensitivity for prostate cancer (PCa) diagnosis and staging.
- A novel diffusion MRI technique, restriction spectrum imaging MRI (RSI-MRI), was developed to enhance PCa imaging.
- RSI-MRI aims to improve the accuracy of detecting and characterizing PCa.
Purpose of the Study:
- To evaluate the efficacy of RSI-MRI compared to standard MRI for detecting extraprostatic extension (EPE) in PCa patients.
- To assess the diagnostic performance of RSI-MRI in staging prostate cancer.
Main Methods:
- A cohort of 28 PCa patients underwent both standard MRI and RSI-MRI prior to radical prostatectomy.
- RSI-MRI utilized cellularity maps derived from restricted isotropic water fractions and z-score standardization.
- Distortion correction was applied to RSI maps using the alternating phase-encode technique.
Main Results:
- RSI-MRI correctly identified EPE in 89% of pT3 patients (8/9), compared to 22% with standard MRI (2/9).
- RSI-MRI accurately identified pT2 disease in the remaining 18 patients.
- One patient was excluded due to inability to perform distortion correction.
Conclusions:
- The novel RSI-MRI technology is feasible and demonstrates potential for significantly improving PCa imaging.
- RSI-MRI shows promise for enhanced diagnosis and staging of prostate cancer.
- Further translational studies are warranted to validate prostate RSI-MRI applications.
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