ESUR prostate MR guidelines 2012

Abstract

The aim was to develop clinical guidelines for multi-parametric MRI of the prostate by a group of prostate MRI experts from the European Society of Urogenital Radiology (ESUR), based on literature evidence and consensus expert opinion. True evidence-based guidelines could not be formulated, but a compromise, reflected by "minimal" and "optimal" requirements has been made. The scope of these ESUR guidelines is to promulgate high quality MRI in acquisition and evaluation with the correct indications for prostate cancer across the whole of Europe and eventually outside Europe. The guidelines for the optimal technique and three protocols for "detection", "staging" and "node and bone" are presented. The use of endorectal coil vs. pelvic phased array coil and 1.5 vs. 3 T is discussed. Clinical indications and a PI-RADS classification for structured reporting are presented.

Key points: This report provides guidelines for magnetic resonance imaging (MRI) in prostate cancer. Clinical indications, and minimal and optimal imaging acquisition protocols are provided. A structured reporting system (PI-RADS) is described.

Fig. 1

Algorithm in imaging men referred with elevated serum prostate specific antigen (PSA), abnormal digital rectal examination (DRE), or family history of prostate cancer

Fig. 2

A 65-year-old man with stage T3a Gleason 4+3 prostate cancer at the left peripheral zone (PZ). a On the axial T2WI at mid-prostate level in the left PZ there is a low signal lesion (outlined) with obliteration of the recto-prostatic angle and extra-capsular extension (arrow). b Magnetic resonance spectroscopic imaging (MRSI) of the normal right side shows low choline+creatine, whereas on (c) MRSI of the tumour shows high choline+creatine. The choline peak of tumour is as equally as high as the citrate peak. This results in a PI-RADS score for MRSI of 3

Fig. 3

A 75-year-old man. After five negative trans-rectal ultrasound (TRUS) biopsies PSA rose to 32 ng/mL, PCa3 = 62. Multi-parametric (Mp)-MRI was performed. a On axial T2WI there is a lenticular area with homogeneous low signal intensity (SI) and unsharp borders: “erased charcoal sign” (outlined), in the mid-prostate level in ventral transition zone (TZ) which is located anterior to the “organised chaos” of benign prostatic hyperplasia (BPH). This pathological area originates from anterior fibromuscular stroma, and thus has a PI-RADS T2WI score of 5. b On the apparent diffusion coefficient (ADC) map this region has a minimum ADC value of 650 (dark area); c On the b = 1400 image this area is white. This results in a PI-RADS score for diffusion weighted imaging (DWI) of 5. d This region shows a curve type 3 (wash-out), and on (e) T2WI with k_trans overlay, there is asymmetric, rather focal enhancement. This gives a PI-RADS score for dynamic contrast enhanced (DCE) MRI of 3 + 2 = 5. f shows the anterior location of the tumour on sagittal T2WI. As MRSI was not performed the sum PI-RADS score is 15/15, which argues in favour of an aggressive (significant) tumour. Thus the overall PI-RADS score for probability of being a significant cancer is 5. MR-guided biopsy revealed a Gleason 4 + 5 = 9 tumour. As the images clearly indicate a tumour, one may argue that one of the parameters may be obviated. However, mp-MRI is not only meant to “detect” a tumour, but also to predict its aggression. If all parameters point into the same direction, the chance of a clinically “significant” tumour (that is Gleason 4+3 or higher) is extremely high. If there is discordance it may be prostatitis or an insignificant (Gleason 3+3) cancer