Keywords:
Pelvis, Abdomen, Oncology, MR, MR-Diffusion/Perfusion, Contrast agent-intravenous, Biopsy, Imaging sequences, Cancer, Neoplasia, Outcomes
Authors:
E. Demozzi, F. M. Cavicchioli, L. Romano, G. Foti, M. Pastorello, A. Molinari, S. Cavalleri, G. Carbognin; Negrar/IT
DOI:
10.1594/ecr2018/C-1174
Methods and materials
Patients
We analyzed the images of 343 men who underwent prostate MRI examinations in our institution between May 2016 and May 2017.
Patients who met the following inclusion criteria were selected: (a) 1.5-Tesla MRI of the prostate,
including a DWI sequence with b 50,
600,
1000 and 1400 sec/ mm2,
(b) increased PSA level (>4 ng/ml) (b) TRUS-guided biopsies performed at our institution within 6 months after MRI.
Exclusion criteria were: (a) previous prostate cancer treatment,
including hormone therapy or radiation; (b) incomplete imaging protocol; (c) TRUS-guided biopsies not performed.
Our final study population consisted of 90 patients (mean age 58 years,
range 48-78) with increased PSA level (mean 8.0 ng/ml,
range 4.0-36),
that underwent mpMRI and TRUS-guided biopsies (Table 1).
MRI acquisition protocol
All images were acquired on a 1.5-Tesla MRI system (Avanto Siemens AG,
Erlangen,
Germany).
A body coil was used for excitation; a pelvic 16-channel phased-array coil was used for signal reception.
Gastrointestinal peristalsis was suppressed by intramuscular administration of 20 mg of scopolamine-butylbromide (Buscopan,
Boehringer Ingelheim),
in absence of contraindications.
Axial T1-weighted (T1w),
axial,
coronal and sagittal T2-weighted (T2w),
Diffusion-Weighted Imaging (DWI) with b values of 50,
600,
1000 and 1400 sec/mm2 and dynamic contrast-enhancement (DCE) sequences were acquired.
Image analysis
Consensus readings of T2-weighted and DWI were performed by two radiologists with 5 and 10 years of experience in prostate MR imaging.
Multiparametric MRI (mp-MRI) was assessed according to the European Society of Urogenital Radiology guidelines according to the Prostate Imaging and Reporting and Data System score [11].
Based on the current uses and capabilities of multiparametric-MRI and MRI-targeted procedures,
for PI-RADS™ v2 clinically significant cancer is defined on pathology/histology as Gleason score ≥7 (including 3+4 with prominent but not predominant Gleason 4 component),
and/or volume≥0.5cc,
and/or extra prostatic extension (EPE).
The criterion for prostate cancer detection on the T2w images was the evidence of a nodular hypointense lesion in the peripheral zone or a very pronounced hypointense sickle-shaped lesion in the transitional zone of the prostate gland and on DWI was the evidence of a focal markedly hypointense nodular lesion on ADC maps and markedly hyperintense on high b-value [11]
Statistical analysis
The sensitivity (se),
specificity (sp),
positive predictive value (PPV),
negative predictive value (NPV) and accuracy (acc) were determined. Statistical analysis was performed using software GraphPad 6 (GraphPad Software Inc.
La Jolla,
CA,
USA).