Fifty-seven patients with pre-operative MR were retrospectively evaluated.
Patients were enrolled by using the following inclusion criteria: (a) pre-operative multiparametric MRI (T2WI+DWI+DCE); (b) pre-operative MRI performed at least three weeks after prostate biopsy; (c) radical prostatectomy within maximum of 6 months after MR study.
All imaging studies were performed with a 1,5 Tesla MR scanner (Achieva,
version 2.6; Philips Medical Systems,
DA Best,
Olanda) with a Torso Cardiac phased array 32 channels coil.
No endorectail coil were used.
An intramuscolar injection of 20 mg of Hyoscine butylbromide (Buscopan; Boehringer Ingelheim,
Ingelheim,
Germany) was given for suppression of motion artifacts.
The MR imaging protocol included T2-weighted turbo spin-echo in three orthogonal planes,
diffusion weighted images (DWI) by using two-dimensional echo-planar imaging with two b values (0 and 1500 sec/mm2) and relative apparent diffusion coefficient (ADC) map and perfusional study (dynamic contrast enhanced - DCE) with 8 seconds temporal resolution after bolus intravenous injection of 0.2 mmol/kg of gadobenate dimeglumine (Multihance,
Bracco) followed by a 20-mL flush of normal saline,
both injected at a rate of 3 mL/s by Spectris Solaris MRI injection system (Medrad).
The MR acquisition parameters are summarized in Table 1.
Sequences
|
Tecnique
|
Repetition Time-TR (ms)
|
Echo Time-TE (ms)
|
Flip Angle
|
Slice Thickness (mm)
|
FOV (mm)
|
Matrix
|
Parallel imaging factor
|
Signal averages
|
T2w sagittal
|
TSE
|
5200
|
100
|
90
|
3
|
180 x 180 x 86
|
256x204
|
/
|
3
|
T2w axial
|
TSE
|
4157
|
100
|
90
|
3
|
180x 180x 66
|
256x198
|
/
|
4
|
T2w coronal
|
TSE
|
4600
|
100
|
90
|
3
|
180x180x76
|
256x198
|
/
|
4
|
Diffusion-w,
axial
|
Single-Shot echo-planar b values (0,
1500)
|
4600
|
74
|
90
|
3
|
180x240x69
|
80x94
|
1.8
|
6
|
T1W axial 3D
|
Spoiled gradient echo
|
4.5
|
2.2
|
10
|
1x1x2
|
189x256x124
|
188x256
|
1.5
|
2
|
Dynamic contrast-enhancement (DCE)
|
T1W axial 3D spoiled gradient echo (38)
|
4.5
|
2.2
|
10
|
1.8x2
|
180x231x80
|
100x129
|
1.5
|
1
|
Tab.
1: MR imaging parameters used in the current study
Five radiology residents with intermediate (6-8 months) experience independently blind reviewed the images obtained with biparametric MRI (T2WI+DWI) and,
after 4 weeks,
those with multiparametric MRI (T2WI+DWI+DCE) and assigned scores on a five-point scale according with the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2 ) (1).
The gold standard was the histological examination evaluated by pathologist according with the 2014 consensus conference ISUP protocol (2) and report by Ball MW et al.
(3),
considering three groups: focal extraprostatic extension (F-EPE,
pT3a),
defined as a few neoplastic glands outside the prostate on 1-2 slides,
nonfocal extraprostatic extension (NF-EPE,
pT3b),
reported as a greater extent of EPE,
and seminal vescicles invasion (SV invasion,
pT3c).