What imaging finding is characteristic of colorectal cancer leading to large bowel obstruction?

The presence of an apple core lesion on a barium enema is indeed a characteristic imaging finding associated with colorectal cancer that leads to a large bowel obstruction. An apple core lesion refers to a specific appearance on radiographic imaging, typically seen in barium studies, where the affected segment of the colon has a constricted, irregular narrowing resembling the shape of an apple core. This is caused by the infiltrative nature of colorectal tumors, which can lead to a circumferential narrowing and obstruction.

Barium enema studies are useful in visualizing the anatomy of the colon and can highlight these lesions effectively. The apple core appearance suggests a malignancy due to the characteristic way the tumor grows around the bowel, leading to obstruction. This finding serves as a critical indicator for clinicians to investigate further, usually warranting additional imaging or colonoscopic evaluation for diagnosis and management.

In contrast, findings such as increased air in the bowel can indicate bowel obstruction but are not specific for colorectal cancer and can be seen in various conditions. Thickening of the bowel wall can occur in a range of diseases, including inflammatory bowel disease, infections, and malignancies, making it a non-specific finding. Gallstones are unrelated to colorectal cancer and do not contribute to large bowel obstruction caused by