Added value of MRI tractography of peri-prostatic nerve plexus to conventional T2-WI in detection of extra-capsular extension of prostatic cancer

Radiol Med. 2019 Oct;124(10):946-954. doi: 10.1007/s11547-019-01047-3. Epub 2019 Jun 13.


Purpose: To evaluate the role of DTI (with fibretracking) and T2-weighted imaging (T2-WI) used together for predicting extra-capsular extension in patients with localized prostate cancer.

Method and materials: Thirty-six patients with biopsy-proven diagnosis of prostatic neoplasia performed MRI and underwent radical prostatectomy. Histopathological analysis showed ECE in 15/36 and capsule sparing in 21/36. By means of T2-WI, ECE was evaluated in a qualitative manner, according to PI-RADS v.2 (two groups with low and high risk of ECE); sensitivity and specificity were calculated for both groups. We performed a quantitative analysis on two tractographic parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) and computed the ratio between the lesion quadrant and its contralateral (L/H ratio). We compared L/H ratios of patients with and without ECE; ROC analyses were performed to determinate ECE cut-off values of tractographic parameters. These cut-off values were used in association with T2-WI to reassess patients and to evaluate whether specificity and sensitivity of ECE detection change.

Results: T2-WI showed a sensitivity of 80% and a specificity of 71% in detection of ECE. Tractography displayed a significant difference in L/H ratio for FA and ADC between patients with and without ECE. The simultaneous use of T2-WI and tractography revealed high sensitivity (100%) on patients with low suspect of ECE (on T2-WI) and high specificity (83%) on patients with high suspect of ECE (on T2-WI).

Conclusion: The morphologic component of T2-weighted imaging and functional aspect of DTI should be interpreted together to more successfully assess the presence of ECE.

Keywords: DTI; Extra-capsular extension; Prostate cancer; Staging; Tractography.

MeSH terms

  • Adult
  • Aged
  • Anisotropy
  • Biopsy
  • Contrast Media
  • Diffusion Magnetic Resonance Imaging
  • Humans
  • Image Interpretation, Computer-Assisted
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Neoplasm Invasiveness / diagnostic imaging
  • Neoplasm Invasiveness / pathology
  • Organometallic Compounds
  • Prospective Studies
  • Prostatectomy
  • Prostatic Neoplasms / diagnostic imaging*
  • Prostatic Neoplasms / pathology*
  • Prostatic Neoplasms / surgery
  • Reproducibility of Results
  • Sensitivity and Specificity


  • Contrast Media
  • Organometallic Compounds
  • gadobutrol