Table 3.

Causes for incomplete colonoscopy.

Cause	Patients, Number (%)	Details
Intraluminal obturation of tumor nature	17 (33%)	Usually, these tumors require surgery and chemotherapy/radiotherapy.
Extraluminal obturation (compression) from a tumor formation	4 (8%)	These patients considered with tumor formation from the colon after incomplete colonoscopy to be correctly diagnosed with tumors of the stomach or ovaries.
Stenotic changes of a non-tumor nature	11 (21%)	Stenotic changes of a non-tumor nature include cases of Crohn’s disease and mucosal edema. The reasons for incomplete FCS are entirely inconsistent with the results of CT colonography.
Congenital diseases with changes in the length of the lumen of the intestinal loops (dolichocolon, megacolon, Hirschsprung)	7 (13%)	In 7 patients, the presence of dolicholone with exhaustion of the device was assumed to be the cause of incomplete FCS. CT colonography was normal in 4 of them, and in 3 patients, CT colonography established carcinoma of the cecum and carcinoma of the rectum, respectively.
Subjective factors	13 (25%)	Pain, poor preparation, contraindications.