Objective: To evaluate the late gadolinium enhancement ratio (LGER) quantitatively in late post-contrast images in multiparametric prostate MRI (mpMRI) for the differential diagnosis of chronic prostatitis and prostate cancer (PCa).
Study design: Descriptive study.
Place and duration of study: Department of Radiology, Suleyman Demirel University, Isparta, Turkey, from January 2018 to October 2021.
Methodology: The data of 111 patients with a diagnosis of PCa and chronic prostatitis, were retrospectively analysed who underwent mpMRI of the prostate were retrospectively analysed. Histopathological verification was available in 57 of 57 prostate carcinoma patients and 20 of 54 chronic prostatitis cases. The detection of lesions from the images and the correlation of the detected lesions with their histopathological diagnoses were made by the joint decision of two radiologists. The LGER measurements were made independently by both radiologists. Signal intensity (SI) values of the lesions were obtained by placing a hand-drawn ROI on pre-contrast and late post-contrast images. Late enhancement ratio was calculated from the ratio of the difference between the pre- and post-contrast SI values to the pre-contrast SI values. The LGER values obtained were statistically compared between the pathologically proven PCa and chronic prostatitis patient groups.
Results: The prostatitis LGER values (103.40 ± 31.54%) were significantly higher than the PCa values (79.71±27.39, p<0.001). The LGER values of lesions with a Gleason score <7 were lower than those of lesions scoring ≥7 (p = 0.004). The LGER values of PI-RADS-3 PCa lesions were lower than those of PI-RADS-4 and PI-RADS-5 (p = 0.002). In the late post-contrast phase, low signal measurements in PI-RADS-3 lesions excluded the presence of prostatitis.
Conclusion: Late contrast enhancement quantitative SI measurements performed in the late contrast phase of mpMRI may enable the differential diagnosis of PCa/prostatitis and a more accurate evaluation of PI-RADS scores in terms of malignancy.
Key words: Prostate cancer, Prostatitis, Gadolinium, Dynamic contrast-enhanced magnetic resonance imaging.