Assessment of Rectal Tumors with Shear-Wave Elastography before Surgery: Comparison with Endorectal US

Abstract

Purpose To compare the value of endorectal ultrasonography (US) with shear-wave elastography (SWE) in staging rectal tumors before surgery. Materials and Methods This prospective study was approved by the institutional review board and written informed consent was obtained. In a pilot cohort from April 2015 to January 2016, 70 patients with rectal adenocarcinomas and/or adenomas confirmed with histopathologic examination underwent both endorectal US and SWE. Tumor stiffness and three regions of reference backgrounds, as well as tumor stiffness ratios (SRs) versus these backgrounds, were analyzed. The optimal staging feature was selected by using receiver operating characteristic analysis, and the concordance rate with pathologic stage was analyzed and compared with endorectal US. The results were validated in an independent cohort of 30 patients from February 2016 to July 2016. Results In the pilot study, from rectal adenoma to stage T3 cancers, the tumor stiffness, stiffness of peritumoral fat, tumor SR versus distant perirectal fat, and tumor SR versus normal rectal wall were significantly increased (all P < .05, correlation coefficients between SWE features and pathologic T stages were 0.589-0.853). Receiver operating characteristic analysis of tumor staging demonstrated that tumor stiffness was the optimal feature with the highest area under the receiver operating characteristic curve (AUC = 0.991-1.000). The cutoff values of stage T1, T2, and T3 cancers were 26.9 kPa, 70.3 kPa, and 112.0 kPa, respectively. For SWE, the diagnostic concordance rate with pathologic stage (95.7%, weighted κ = 0.962) was higher than that of endorectal US (75.7%, weighted κ = 0.756). In the validation cohort, similar findings were revealed for diagnostic concordance rate (93.3% vs 76.7%; weighted κ = 0.927 vs 0.651) and diagnostic performance of tumor staging (AUC = 0.950-1.000 vs 0.700-0.833). Conclusion By using the feature of tumor stiffness at SWE, the accuracy of preoperative staging for rectal tumors was improved compared with endorectal US in the pilot study, but was not significantly different in the validation cohort, potentially due to small sample size. RSNA, 2017 Online supplemental material is available for this article.

The utility of preoperative radiological evaluation of early rectal neoplasia: a systematic review and meta‐analysis

“…The literature search identified 913 abstracts, of which 35 were judged relevant for full assessment. After data extraction, 11 articles met the inclusion criteria and were included in the meta-analysis [12,[20][21][22][23][24][25][26][27][28][29]. The remaining articles did not meet the inclusion criteria and were excluded (Fig.…”

The EFSUMB Guidelines and Recommendations for the Clinical Practice of Elastography in Non-Hepatic Applications: Update 2018

“…Another group found good correlation between diffusion-weighted MR imaging which is associated with fibrosis, and SWE of malignant rectal tumors [229]. Another study assessed the performance of ERUS for rectal tumors using SWE using an 8 MHz endorectal transducer, finding that the tumor stiffness measurements corresponded accurately to the pathological tumor T-stage and diagnostic accuracy of tumor staging improved from 76.7 % to 93.3 % [230].…”

Using shear wave elasticity in normal terminal ileum of a healthy southwest Chinese population: a pilot study of reference elasticity ranges

“…It was first used in GI diseases in 2013 by Dillman et al (10), who conducted a Crohn's disease animal model. Several studies have reported the value of using SWE, especially in inflammatory bowel disease (IBD) and rectal neoplasms (10)(11)(12)(13)(14)(15)(16)(17)(18)(19). For instance, it has proven effective in the differentiation of fibrotic from inflammatory strictures in Crohn's disease (14,18) and in assessing and staging rectal tumors (12,13,15).…”