Keywords:
Cancer, Biopsy, MR, CT, Genital / Reproductive system male, Oncology, Abdomen
Authors:
P. Vivian, S. Dupre; QLD/AU
DOI:
10.1594/ranzcr2016/R-0059
Methods and materials
All MRI prostate scans performed at our institution between November 2014 and March 2016 were reviewed retrospectively on PACS.
MRI scans demonstrating suspected prostate lesions (PI-RADS 4 & 5) were included in the study if an accompanying contrast enhanced CT of the abdomen/pelvis performed within six months of the MRI scan.
All CT scans were performed with contrast in the portal venous phase (approximately 70 seconds after injection of contrast).
The size and location of the lesion was recorded and only lesions measuring 10mm in at least two orthogonal planes were included.
Histology of TRUS biopsy or radical resection was collected if available.
The CT scans were reviewed by two radiologists who were informed that a prostate lesion (PI-RADS 4/5) was detected on MRI,
but were blinded to all other details of the lesion.
The scans were viewed on a diagnostic workstation in the axial plane with the ability to adjust window width and length.
The radiologists graded the CT scans from 1-3; 1 – No focal dense/enhancing lesion detected,
2 – “Subtle” (subtle dense/enhancing mass that would be flagged as a possible cancer or potential target for biopsy in clinically suspected prostate cancer) and 3 – “Overt” (clearly apparent dense/enhancing mass highly suspicious for prostate cancer in the context of clinically suspected prostate cancer).
The MRI lesions were categorised by location.
Peripheral zone lesions were classified into four groups; posterior midline/symmetric,
posterior-lateral,
anterior midline/symmetric,
anterior-lateral.
The other categories were Diffuse (greater than >50% of the prostate) and Transition zone (excluding lesions arising from the peripheral zone invading into the transitional zone).
Concordance between the readers was evaluated with Cohen’s Kappa test and associations between lesion visibility and lesion location was analysed with a Chi-square Test.