[Implications of PI-RADS Version 1 and Updated Version 2 on the Scoring of Prostatic Lesions in Multiparametric MRI]

BACKGROUND

A revised version of the PI-RADS scoring system has been introduced and score-related variability between version 1 and 2 may be suspected. This study aimed to assess the PI-RADS scores derived from version 1 (v1) and the updated version 2 (v2).

MATERIAL AND METHODS

61 patients with biopsy-proven prostate cancer (PCa) and 90 lesions detected on pre-biopsy 3-Tesla multiparametric MRI were included in this retrospective analysis. 2 experienced radiologists scored all lesions in consensus. Lesion scores differing between PI-RADS v1 and v2 were further analyzed. Histology data from radical prostatectomy (RP) were included when available.

RESULTS

The PI-RADS v1 and v2 score differed in 52% of patients (32/61) and in 39% of lesions (35/90). On a lesion basis, the reason for the differences were related to sum score in v1 vs. categorical system in v2 in 51% (18/35) of lesions, cutoff between PI-RADS 4 and 5 based on lesion size in v2 as opposed to the sum score in v1 in 31% (11/35) and were inconclusive in 17% (6/35). The RP subgroup indicates enhanced detection of PCas with GS 3+3 and GS 3+4 in v2.

CONCLUSION

PI-RADS scores of prostatic lesions frequently differed between v1 and v2, the major reasons for these differences being score-related. In men undergoing RP, PI-RADS v2 improved detection of low risk PCa, but did not increase accuracy for discrimination of GS 3+4 vs. GS≥4+3 compared to v1. Urologists should be aware of the system-related differences when interpreting PI-RADS scores.

[Real-time MRI/US fusion-guided biopsy in biopsy-naïve and pre-biopsied patients with suspicion for prostate cancer]

BACKGROUND

Magnetic resonance imaging (MRI)/ultrasound (US) fusion-guided biopsy detects more prostate cancer (PCa) than transrectal US (TRUS)-guided biopsy in patients with an indication for prostate re-biopsy. The aim of this study was a) to compare the detection rates of MRI/US fusion-guided biopsy with conventional TRUS in a double centre cohort and b) to investigate the influence of the number of pre-biopsies on the PCa detection rate.

MATERIAL AND METHODS

In the period from January 2012 to July 2014, 310 consecutive patients gave written informed consent and underwent 3 Tesla MRI scans of the prostate. All patients had at least one PCa suspicious lesion in the MRI and were biopsied by MRI/US fusion followed by a conventional 10-core biopsy of the prostate. Detection rates based on technique, Gleason score and number of pre-biopsies were calculated.

RESULTS

The overall detection rate of the study was 51% (158 patients). Among these 158 patients a histopathological Gleason score of 6 was detected in 60 patients (38%), a Gleason score of 7 in 54 patients (34%) and a Gleason score≥8 in 44 patients (28%). MRI/US fusion-guided biopsy detected 110 (69.7%) of the overall detected 158 PCa. TRUS-guided biopsy detected a higher rate of Gleason score 6 (54%) and a lower rate of Gleason score≥8 (15%) lesions in comparison to 38% Gleason 6 and 28% Gleason≥8 in the MRI/US fusion-guided biopsy, respectively. Furthermore, a lower Gleason score was observed in patients with more than one pre-biopsy. The detection rate in biopsy-naïve patients undergoing MRI/US fusion was 75% (40 patients) among 75% detected Gleason score≥7.

CONCLUSION

MRI/US fusion-guided biopsy detected more PCa and also more clinically significant cancer than conventional TRUS. In our cohort patients with more than one pre-biopsy showed lower Gleason scores. The included patients with an initial MRI/US fusion-guided biopsy should be further investigated.

[Real-time MRI/US fusion-guided biopsy improves detection rates of prostate cancer in pre-biopsied patients]

BACKGROUND

According to the guidelines of the European Association of Urology (EAU) on prostate cancer (PCa) in 2013, patients with increasing prostate-specific antigen (PSA) levels, suspicious digital rectal examination (DRE) or high-grade prostatic intraepithelial neoplasia after negative prostate biopsy (PB) should undergo a repeat biopsy. Low cancer detection rates in the repeat biopsy illuminate the dilemma of the international gold standard of transrectal ultrasound (TRUS) guided PB in the detection of PCa. Our study evaluated the combination of TRUS and prostate magnetic resonance imaging (MRI) and its reported high sensitivities and high specificities by using real-time MRI/US fusion-guided biopsy. The detection of clinically significant PCa was investigated.

MATERIAL AND METHODS

128 consecutive patients in the period of January 2012 to August 2013 were included. All patients had at least one TRUS-guided biopsy with negative findings and the clinical indication for a systematic re-biopsy. Prior to the MRI/US fusion all patients underwent a 3 Tesla prostate MRI without endorectal coil. The MRI data were uploaded to a modern US system. The B-mode, power-mode, elastography and CEUS imaging were used to classify the suspicious lesions from the MRI on a scale of 0-3 and a US sum score was calculated. The lesion was consecutively biopsied by real-time MRI/US fusion followed by a systematic 10 core biopsy.

RESULTS

Among 128 patients 51 PCa could be detected (39.8%). From these 51 PCa cases, clinically significant PCa was detected by MRI/US fusion-guided biopsy as follows: Gleason score >7 in 9 of 10 patients; Gleason score=7 in 14 of 20 patients and Gleason score <7 in 13 of 21 patients. A positive correlation was shown between the US sum score and the associated PI-RADS score in 65 patients in whom lesions were classified by PI-RADS. A positive correlation was further shown between the US sum score and the Gleason score of all suspicious and biopsied lesions. MRI/US fusion and TRUS-guided biopsy combined, detected 30 of 51 PCa; 6 of 51 PCa were detected by MRI/US fusion alone and 15 of 51 PCa by conventional TRUS-guided biopsy alone.

CONCLUSION

Real-time MR/US fusion increases detection rates of PCa in patients undergoing repeat biopsy. Especially, clinically significant PCa with a Gleason score ≥ 7 were almost exclusively detected by MR/US fusion-guided biopsy.

[Detection of prostate cancer by real-time MR/ultrasound fusion-guided biopsy: 3T MRI and state of the art sonography]

PURPOSE

Multiparametric MRI of the prostate is a noninvasive diagnostic method with high sensitivity and specificity for prostate cancer. The aim of this study is to evaluate whether prostate cancer detection rates of transrectal ultrasound (TRUS)-guided biopsy may be improved by an image fusion of state-of-the-art ultrasound (CEUS, elastography) and MR (T2w, DWI) imaging.

MATERIALS AND METHODS

32 consecutive patients with a history of elevated PSA levels and at least one negative TRUS-guided biopsy with clinical indication for a systematic re-biopsy underwent multiparametric 3 T MRI without endorectal coil. MR data (T2w) were uploaded to a modern sonography system and image fusion was performed in real-time mode during biopsy. B-mode, Doppler, elastography and CEUS imaging were applied to characterize suspicious lesions detected by MRI. Targeted biopsies were performed in MR/US fusion mode followed by a systematic standard TRUS-guided biopsy. Detection rates for both methods were calculated and compared using the Chi²-test.

RESULTS

Patient age was not significantly different in patients with and without histologically confirmed prostate cancer (65.2 ± 8.0 and 64.1 ± 7.3 age [p = 0.93]). The PSA value was significantly higher in patients with prostate cancer (15.5 ± 9.3 ng/ml) compared to patients without cancer (PSA 10.4 ± 9.6 ng/ml; p = 0.02). The proportion of histologically confirmed cancers in the study group (n = 32) of the MR/US fusion biopsy (11/12; 34.4 %) was significantly higher (p = 0.01) in comparison to the TRUS systematic biopsy (6/12; 18.8 %).

CONCLUSION

Real-time MR/US image fusion may enhance cancer detection rates of TRUS-guided biopsies and should therefore be studied in further larger studies.