Localising Prostate Cancer: Comparison of Endorectal Magnetic Resonance (MR) Imaging and 3D-MR Spectroscopic Imaging with Transrectal Ultrasound-Guided Biopsy

Abstract

Background: Magnetic resonance imaging (MRI) and MR spectroscopic imaging (MRSI) have been gaining acceptance as tools in the evaluation of prostate cancer. We compared the accuracy of transrectal ultrasound (TRUS)-guided biopsy and dynamic contrast-enhanced MRI combined with three-dimensional (3D) MRSI in locating prostate tumours and determined the influence of prostate weight on MRI accuracy. Patients and Methods: Between March 1999 and October 2006, 507 patients with localised prostate cancer underwent radical prostatectomy (RP) at the Jules Bordet Institute. Of these, 220 had undergone endorectal MRI (1.5 T Siemens Quantum Symphony) and 3D-MRSI prior to RP. We retrospectively reviewed data on tumour location and compared the results obtained by MRI and by TRUS-guided biopsy with those obtained on histopathology of the RP specimen. Results: Patient data were as follows: median age 62.4 years (45–74); median PSA 6.36 ng/ml (0.5–22.6); 73.6% of patients had non-palpable disease (T1c); median biopsy Gleason score 6 (3–9); median RP specimen weight 50 g (12–172); median pathological Gleason score 7 (4–10); 68.64% of patients had organ-confined (pT2) disease. Tumour localisation was correlated with RP data in a significantly higher percentage of patients when using MRI rather than TRUS-guided biopsy (47.4 vs. 36.6%, p < 0.0001). MRI was marginally superior to TRUS-guided biopsy in detecting malignancy at the prostate apex (48.3 vs. 41.9%, p = 0.0687) and somewhat better at the prostate base (46 vs. 39.1%, p = 0.0413). It was highly significantly better at mid-gland (52 vs. 41.1%, p = 0.0015) and in the transition zone (40.1 vs. 24.3%, p < 0.0001). MRI had higher sensitivity in larger (≧50 g) than smaller (<50 g) prostates (50.3 vs. 42.2%, p = 0.0017). Conclusions: MRI was superior to TRUS-guided biopsy in locating prostate tumours except at the gland apex. MRI was more accurate in larger (≧50 g) than smaller prostates.

Long-term outcomes of nonpalpable prostate cancer (T1c) patients treated with radical prostatectomy

“… 18 Magnetic resonance imaging detects tumors better than transrectal ultrasound-guided biopsy, especially in an enlarged prostate. 19 Some imaging modalities can be used to detect cancers with a volume of <0.5 cm 3 . 20 Using recent technologies, however, the precise evaluation of nonpalpable prostate tumors remains to be obtained until now.…”

Seminal Vesicle Invasion: Accuracy and Analysis of Infiltration Patterns with High-Spatial Resolution T2-Weighted Sequences on Endorectal Magnetic Resonance Imaging

“…The study was conducted at 1.5 tesla and was based on T2-weighted imaging. However, addition of functional, multiparametric imaging techniques to high-resolution T2-weighted imaging demonstrated only a marginal increase of specificity and sensitivity for detection of SVI compared to T2-weighted imaging alone [28,34,35,36]. Assessing functional imaging of multiparametric MRI, DWI showed incremental benefit in contrast to dynamic contrast-enhanced imaging [28].…”

Editorial Comment to Magnetic resonance spectroscopy imaging‐directed transrectal ultrasound biopsy increases prostate cancer detection in men with prostate‐specific antigen between 4–10 ng/mL and normal digital rectal examination

“…Confirmatory results were found in a retrospective study carried out by our group on 507 men who had undergone RP for prostate cancer. Of these, 220 had undergone MRI and 3D‐MRSI before RP . The sensitivity of TRUS‐guided biopsy improved on increasing the number of cores from six to 10, but did not improve any further on increasing from 10 to 16 cores including the TZ.…”

“…did not use the real‐time MR/US image fusion, and because of the potential variability between MRI and ultrasound, their results should be interpreted with caution. The anterior part of the prostate is difficult to access by TRUS‐biopsy, and particularly for large prostates for which MRI is more accurate …”