Comparison of multiparametric and biparametric magnetic resonance imaging protocols for prostate cancer diagnosis by radiologists with different experience

BACKGROUND: Magnetic resonance imaging can detect clinically significant prostate cancer and diagnose extracapsular extension and cancer stage. A scanning protocol that includes only T2-weighted and diffusion-weighted images represents a viable alternative to multiparametric magnetic resonance imaging provided that the high diagnostic accuracy of the test is maintained. In recent studies, biparametric and multiparametric magnetic resonance imaging demonstrated slight differences in the diagnostic accuracy in detecting prostate cancer.

AIM: To compare the diagnostic accuracy of biparametric and multiparametric magnetic resonance imaging for the detection of clinically significant prostate cancer using PI-RADS v2.1 with magnetic resonance imaging-guided multifocal biopsy as the gold standard.

MATERIALS AND METHODS: This retrospective study initially processed the medical records of 126 patients. The inclusion criteria were as follows: presence of PI-RADS 2.1 multiparametric magnetic resonance imaging, clinical information on free and bound prostate-specific antigen blood levels, a multifocal prostate biopsy performed, and a time interval between magnetic resonance imaging and biopsy of no more than 14 days. Three investigators (radiologists with <2, 2–5, and >5 years of experience) independently evaluated biparametric magnetic resonance imaging of the prostate for the presence of pathological foci. After 2 weeks, the researchers evaluated the multiparametric magnetic resonance imaging dataset of the prostate. Each lesion detected, starting from PI-RADS category 3, was compared with the result of a multifocal fusion biopsy. The biopsy result was presented as a sum of Gleason scores, and a Gleason score of ≥7 was considered clinically relevant. According to magnetic resonance imaging data, findings meeting PI-RADS criteria 4 and 5 were considered tumor foci.

RESULTS: The best values of sensitivity and specificity of foci detection on magnetic resonance imaging of the prostate gland were 62.5% and 74.6%, respectively. The highest diagnostic accuracy achieved was 70.1%. Magnetic resonance imaging had higher specificity rates for detecting prostatic foci when interpreted by radiologists with 2 years and >5 years of experience.

CONCLUSION: Both biparametric and multiparametric magnetic resonance imaging of the prostate demonstrated suboptimal diagnostic accuracy. The sensitivity and specificity of the method tended to improve with increasing experience of the radiologist. Biparametric protocols of prostate scanning have a definite economic advantage over multiparametric protocols because of the absence of contrast agents and consumables and a significant decrease in magnetic resonance scanner loading time; however, their use can lead to a decrease in the diagnostic accuracy of the method.