Diagnostic accuracy of 68 Ga-PSMA PET/MRI and multiparametric MRI in detecting index tumours in radical prostatectomy specimen

Int J Clin Pract. 2021 Aug;75(8):e14287. doi: 10.1111/ijcp.14287. Epub 2021 May 20.

Abstract

Objective: To evaluate the diagnostic accuracy of the 68 gallium (68 Ga) prostate-specific membrane antigen (PSMA) positron emission tomography/magnetic resonance imaging (PET/MRI) and multiparametric MRI (mpMRI) by region-based comparison of index tumour localisations using histopathological tumour maps of patients who underwent radical prostatectomy because of clinically significant prostate cancer.

Patients and methods: The study included 64 patients who underwent radical prostatectomy after primary staging with mpMRI and 68 Ga-PSMA PET/MRI. Diagnostic analysis was performed by dividing the prostate into four anatomic regions as left/right anterior and left/right posterior. The extension of the lesions in mpMRI and the pathological uptake in 68 Ga-PSMA PET/MRI were matched separately for each region with the extension of the index tumour into each region.

Results: The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and the accuracy of mpMRI and 68 Ga-PSMA PET/MRI are shown as 55.7%, 91.8%, 80.6%, 77.2%, 78.1%, and 60.8%, 94.3%, 86.8% 79.8%, 83.5%, respectively. 68 Ga-PSMA PET/MRI has higher sensitivity and specificity compared with mpMRI. However, no statistically significant difference was found (P = .464). Combined imaging had significantly higher diagnostic accuracy compared with mpMRI and 68 Ga-PSMA PET/MRI (change in AUC: 0.084 and 0.046, P < .001 and P = .028, respectively), while no statistically significant difference was found between mpMRI and 68 Ga-PSMA PET/MRI (change in AUC: 0.038, P = .246).

Conclusion: 68 Ga-PSMA PET/MRI had higher clinical diagnostic accuracy in prostate cancer compared with mpMRI. Diagnostic accuracy was significantly increased in the combined use of both imaging modalities.

MeSH terms

  • Humans
  • Male
  • Multiparametric Magnetic Resonance Imaging*
  • Positron Emission Tomography Computed Tomography
  • Positron-Emission Tomography
  • Prostatectomy
  • Prostatic Neoplasms* / diagnostic imaging
  • Prostatic Neoplasms* / surgery
  • Radiopharmaceuticals

Substances

  • Radiopharmaceuticals