Strain Assessment in Surgically Resected Inflammatory and Neoplastic Bowel Lesions

Abstract

Purpose: To investigate whether ultrasound-based strain imaging can discriminate between colorectal adenocarcinomas and stenotic Crohn?s lesions in newly resected surgical specimens. Materials and Methods: Resected surgical specimens from 27 patients electively operated for colorectal tumors or stenotic lesions from Crohn?s disease were prospectively examined with ultrasonography using a Hitachi HV 900 US scanner with real-time elastography (RTE). Three different methods were applied to assess tissue strain: A four-level categorical visual classification, a continuous visual analog scale (VAS, 0???100) and a strain ratio (SR) measurement between the lesion and surrounding reference tissue. The imaged sections were marked and subsequently examined by a pathologist. Results from RTE were evaluated according to diagnosis, degree of fibrosis, inflammatory parameters, tumor stage and grade. Results: 16 sections from Crohn?s lesions, 18 sections from adenocarcinomas and 4 sections from adenomas were examined. Both adenocarcinomas and Crohn?s lesions were found to be harder than the surrounding tissue, but they could not be discriminated from each other by any of the strain imaging evaluation methods. All adenocarcinomas had significantly higher strain ratios than adenomas. The categorical classification differentiated poorly between Crohn?s lesions, adenocarcinomas and adenomas. Categorical evaluation and VAS score showed fair interobserver agreement. SR measurements provided semi-quantitative strain data and added improved information about elasticity properties, despite substantial intra-observer variation. Conclusion: Sonoelastography with SR measurements and visual evaluation of strain differences could not differentiate stenotic Crohn?s lesions from adenocarcinomas in resected bowel specimens. A small number of adenomas were found to be significantly softer than adenocarcinomas using the same evaluation methods. The tumor stage or grade did not have a significant impact on the elastography results.

Strain Ratio as a Quantification Tool in Strain Imaging

“…Histology was the reference standard. For further details on the patients and method, please refer to the original publication [14].…”

“…The image of a scanned bowel wall with an adenocarcinoma is shown in Figure 3. The data on SR were previously published, but IQR/median was not used as a variability parameter [14]. SR was recorded between the normal bowel wall and peri-colic fat/connective tissue and the lesion of A (lesion) and B (reference).…”

Bowel elastography – a pilot study for developing an elastographic scoring system to evaluate disease activity in pediatric Crohn’s disease.

“…SE=B -sonoelastrographic type B; SE=C -sonoelastrographic type C; SR lower -strain ratio values lower than the those of the reference tissue (muscle of the anterior wall of the abdomen); CRP -C reactive protein; ESR -erythrocyte sedimentation rate; CAL -calprotectine; CI -confidence interval. SE type B -predictor for complications, SE type C -predictor for increased CRP, SE type B and SR lower -combined predictors for elevated ESR, SE type B or C -predictors for increased calprotectine have been no studies published yet demonstrating its role [10,11].…”

“…The examination was initially performed on the longitudinal view, afterwards the transducer was rotated 90 degrees for the transverse view of the intestinal segment and the compressions were mild and regular. An equal ratio was considered normal or a sign of remission; a higher target strain as compared with the muscles represented inflammation and a lower target strain was interpreted as fibrosis (fig 3) [10,11].…”

Diagnosis of one small bowel tumor: the role of conventional ultrasound and elastography

“…The recent European Guidelines suggest the use of elastography in the characterization of focal lesions of the digestive tract and in the differentiation between inflammatory and fibrotic stenosis in patients with Crohn's disease (2013, [1]) Havre et al [2] performed elastography on adequately prepared surgical specimens from 27 patients (18 specimens of adenocarcinoma, 4 specimens of adenoma and 16 specimens from patients with intestinal stenosis in Crohn's disease) encountering increased stiffness compared to the adjacent bowel wall in both adenocarcinoma and intestinal stenosis in Crohn's disease.…”