CT colonography virtual colonoscopy

This new technology (described further later) is not as yet approved for use as a screening test. No randomized controlled studies are available investigating the ability of CTC to reduce CRC morbidity. Until recently, no screening studies were available to evaluate the efficacy of CTC, and the accuracy of the test had to be extrapolated from multiple studies using primarily surveillance-type populations. The appeal of CTC in the screening setting derives from the fact that the examination is a...

Extrahepatic disease

Colon Carcinoma Barium Enem

CT technology has evolved rapidly from incremental to single-slice helical to 4-, 8-, 16-, 64-, and 256-slice multidetector scanners now commercially available. Images obtained from 16-slice (or greater) scanners can be near-isotropic (ie, nearly perfectly cubical voxels without distortion of anatomy). This allows for so-called ''volumetric imaging'' during a single breathhold in many instances covering the entire chest, abdomen, and pelvis. The acquisition of ultrathin slices (typically 0.5,...

Positron emission tomography in rectal cancer

Low rectal cancers represent a particular patient population that may behave differently from the remainder of patients with CRC. The low rectum has lymphatic drainage to inguinal nodes and the more common pelvic side wall and intra-abdominal nodes. The venous drainage of the low rectum may bypass the liver, and lead to increase in pulmonary metastases in this group. For these very reasons a recent investigation found that FDG PET-CT altered treatment plans in patients with untreated rectal...

Primary and recurrent rectal cancer

Rectal Cancer

Because of its extraperitoneal location, close proximity to other organs, higher rate of recurrence, higher morbidity, amenability to different treatment strategies, and requirement for subspecialized surgery, rectal cancer is addressed separately from colon cancer in this section. Approximately 45,000 cases of rectal cancer are diagnosed each year, representing about one third of new cases of CRC. Recurrent disease is more common in the rectum than in the colon and can result in pain,...