Date of Award


Document Type


Degree Name

Master of Medicine (MMed)

First Supervisor/Advisor

Sudihir Vinayak

Second Supervisor/Advisor

Samuel Gitau Nguku

Third Supervisor/Advisor

Edward Chege


Imaging and Diagnostic Radiology (East Africa)


Background: Traditionally, the diagnosis of prostate cancer has been based on an elevated prostate specific antigen or an abnormal digital rectal examination and confirmed histologically following prostate biopsy. This has led to a number of men without cancer or with clinically insignificant disease undergoing unwarranted prostate biopsies and suffering consequent complications. Pre-biopsy multi-parametric MRI plays a vital role in determining men with clinically significant cancer who need biopsy and those with a negative MRI who can safely avoid an unwarranted biopsy. Whereas studies on the value of multi-parametric MRI have been done elsewhere, there is variation in prevalence of prostate cancer in different populations which affects the predictive value, varying thresholds in defining clinically significant cancer as well as possible differences in tumour biology with our population.

Objective: To determine the diagnostic accuracy of multi-parametric MRI in differentiating clinically significant and clinically insignificant prostate cancer using histopathology as the reference standard.

Methods: The diagnostic accuracy of multi-parametric MRI using transrectal ultrasound guided biopsy as the reference test was established for 133 men who underwent multi-parametric MRI and biopsy between January 2016 – March 2019. The multi-parametric MRI images were reviewed and reported by two independent consultant radiologists. Clinically significant cancer was defined as PI-RADS score of ≥3 and Gleason score ≥3 + 4 (grade group ≥2).

Results: Multi-parametric MRI of the prostate was found to have 92% sensitivity, 47.8% specificity, 86.8% negative predictive value and 62% positive predictive value.

Conclusion: Multi-parametric MRI has a high sensitivity and a negative predictive value validating its use in pre-biopsy evaluation of men at risk of prostate cancer to safely avoid unnecessary prostate biopsy and to guide biopsy of suspicious lesions.

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