Strain Elastography Evaluation of Rectal Tumors: Inter- and Intraobserver Reproducibility

Area of Science:

• Gastroenterology and Hepatology
• Medical Imaging
• Oncology

Background:

• Elastography is an emerging imaging technique for identifying malignant tissues.
• Accurate differentiation of rectal adenomas and adenocarcinomas is crucial for effective treatment planning and staging.

Purpose of the Study:

• To assess the inter- and intraobserver reproducibility of endorectal strain elastography in distinguishing between rectal adenomas and adenocarcinomas.
• To compare the diagnostic performance of strain elastography with conventional endorectal ultrasonography (ERUS).

Main Methods:

• 110 elastography video loops with ERUS overlay were evaluated by eight blinded observers on two separate occasions.
• Observers used a visual analog scale (VAS) and a categorical W-score for elastography assessment.
• Histopathology of surgical specimens served as the reference standard for tumor staging (pT-stages).

Main Results:

• Strain elastography demonstrated high intraobserver (0.86–0.97) and interobserver (0.99) reproducibility.
• Elastography achieved a sensitivity of 0.94 and specificity of 0.71 for differentiating adenomas from adenocarcinomas.
• Elastography showed superior performance compared to ERUS, with higher accuracy (0.89 vs. 0.79).

Conclusions:

• Offline visual assessment of endorectal strain elastography is highly reproducible among blinded observers.
• Strain elastography shows significant correlation with pT-stages and outperforms ERUS in differentiating rectal tumors.
• This technique holds promise for improving the accuracy of rectal cancer staging.