Evaluation of Diffusion Weighted Imaging in the Context of Multi-Parametric MRI of the Prostate in the assessment of suspected low volume prostatic carcinoma

摘要

Data from a multi-parametric MRI study of patients with possible early-stageprostate cancer was assessed with a view to creating an efficient clinicalprotocol. Based on a correlation analysis suggesting that diffusion-weightedimaging (DWI) scores are more strongly correlated with overall PIRADS scoresthan other modalities such as dynamic contrast enhanced imaging orspectroscopy, we investigate the combination of T2-weighted imaging (T2w) andDWI as a potential diagnostic tool for prostate cancer detection, staging andguided biopsies. Quantification of the noise floor in the DWI images andcareful fitting of the data suggests that the mono-exponential model provides avery good fit to the data and there is no evidence of non-Gaussian diffusionfor $b$-values up to 1000 s/mm$^2$. This precludes the use of kurtosis or othernon-Gaussian measures as a biomarker for prostate cancer in our case. However,the ADC scores for healthy and probably malignant regions are significantlylower for the latter in all 20 but one patient. The results suggest that asimplified mp-MRI protocol combining T2w and DWI may be a good compromise for acost and time efficient, early-stage prostate cancer diagnostic programme,combining robust MR biomarkers for prostate cancer that can be reliablyquantified and appear well-suited for general clinical practice.