Endorectal

Endorectal is a medical term describing something located within or introduced into the rectum. It is used as a descriptor for procedures, instruments, and imaging modalities that examine or treat the interior of the rectum. The term stems from endo- meaning within and rect- referring to the rectum.

Common uses of endorectal techniques include endorectal ultrasound (ERUS) and endorectal magnetic resonance imaging (MRI) with specialized coils. ERUS employs a probe inserted into the rectum to obtain high-resolution images of the rectal wall layers and nearby structures. This modality is widely used to stage rectal cancer, assessing the depth of tumor invasion (T stage) and nodal involvement, and to evaluate anorectal diseases such as inflammatory or neoplastic lesions, fistulas, and complex polyps. Endorectal MRI with an internal coil can provide enhanced visualization of pelvic anatomy, particularly for rectal cancer staging and planning treatment near the mesorectal fascia or adjacent organs.

Technique and safety considerations are context-dependent. For ERUS, the examination is performed with the patient in a comfortable position, using lubrication and often local anesthesia or topical anesthetic; it is typically carried out by a radiologist or gastroenterologist. The procedure generally lasts 15–30 minutes and carries a low risk of complications, such as transient discomfort, mild bleeding, or mucosal irritation; serious complications are rare. For endorectal MRI, an internal coil is placed in the rectum prior to image acquisition, with the patient usually still and unaware during the scan. The accuracy and utility of endorectal methods depend on the clinical scenario and operator experience, and they are often used in conjunction with other imaging modalities.

See also: transrectal procedures, endoluminal imaging, colorectal cancer staging.

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