Magnetic resonance imaging for clinical management of rectal cancer: Updated recommendations from the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting

Abstract

ObjectivesTo update the 2012 ESGAR consensus guidelines on the acquisition, interpretation and reporting of magnetic resonance imaging (MRI) for clinical staging and restaging of rectal cancer.MethodsFourteen abdominal imaging experts from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) participated in a consensus meeting, organised according to an adaptation of the RAND-UCLA Appropriateness Method. Two independent (non-voting) Chairs facilitated the meeting. 246 items were scored (comprising 229 items from the previous 2012 consensus and 17 additional items) and classified as ‘appropriate’ or ‘inappropriate’ (defined by ≥ 80 % consensus) or uncertain (defined by < 80 % consensus).ResultsConsensus was reached for 226 (92 %) of items. From these recommendations regarding hardware, patient preparation, imaging sequences and acquisition, criteria for MR imaging evaluation and reporting structure were constructed. The main additions to the 2012 consensus include recommendations regarding use of diffusion-weighted imaging, criteria for nodal staging and a recommended structured report template.ConclusionsThese updated expert consensus recommendations should be used as clinical guidelines for primary staging and restaging of rectal cancer using MRI.Key Points• These guidelines present recommendations for staging and reporting of rectal cancer. • The guidelines were constructed through consensus amongst 14 pelvic imaging experts. • Consensus was reached by the experts for 92 % of the 246 items discussed. • Practical guidelines for nodal staging are proposed. • A structured reporting template is presented. Electronic supplementary materialThe online version of this article (10.1007/s00330-017-5026-2) contains supplementary material, which is available to authorized users.

Value of MRI morphologic features with pT1‐2 rectal cancer in determining lymph node metastasis

“…The previous study confirmed that in colorectal patients with only one metastatic LN, the 5‐year survival rate was significantly higher than those with greater than or equal to two LNs (67% to 39.6%) . Some MRI studies also established that the number of MR‐LN should be included in the assessment of rectal cancer . Our study found that the MR‐LN numbers were different in subgroups, and that was considered as the risk factor of LNM in univariate logistic regression analysis.…”

“…Pathologically, LVI or vascular infiltration was suggested as a significant risk factor for LNM or distant metastasis in other surveys . At the European Society of Gastrointestinal and Abdominal Radiology Consensus Conference, the shape, border, and signal heterogeneity of LNs were considered as morphologically suspicious criteria, and our research had a similar result with that …”

Magnetic resonance tumour regression grade and pathological correlates in patients with rectal cancer

“…Nodes with an irregular margin or heterogeneous internal signal were judged as suspicious of metastasis, and those smaller than 5 mm were generally considered benign. These are similar to expert recommendations. The readers tended to apply a sensitive threshold when interpreting equivocal subjective nodal findings to help avoid neglecting subtle metastatic nodes, given that most patients were to undergo CRT regardless, according to the NCCN guidelines.…”

Higher‐order diffusion MRI characterization of mesorectal lymph nodes in rectal cancer

“…ADC is the worst performing model, with an AUC value of 0.60, whereas IVIM‐Kurtosis is the best performing model with an AUC of 0.73; however, the difference does not reach statistical significance according to the DeLong test ( P = .19) . Figure C shows that IVIM‐Kurtosis also provides a better differentiation between benign and malignant nodes (AUC = 0.80) compared to the standard clinical T 2 classification based on the European Society of Gastrointestinal and Abdominal Radiology 2016 criteria (AUC = 0.74 for reader 1; AUC = 0.59 for reader 2), which takes into consideration lymph node size, shape, contour, and heterogeneity. Moreover, combining IVIM‐Kurtosis and T 2 results significantly improves the classification compared to T 2 ‐weighted images alone ( P = .08 for reader 1; P = 0.007 for reader 2).…”