Multislice CT complements ultrasound in GI staging

While both multislice CT and endoscopic ultrasound can evaluate local extension of esophageal tumors, CT can also image distant metastases in the lymph nodes, lungs, and liver with a single exam. It thus provides superior staging of T3 and T4 cancers, according to a study presented at the 2005 European Congress of Radiology. CT is not without weaknesses, however.

Dr. Ahmed Ba-Ssalamah and colleagues at the Medical University of Vienna enrolled 23 patients with esophageal carcinoma. The patients underwent endoscopic sonography and contrast-enhanced MSCT using a gas-water GI-filling technique.

Endoscopic ultrasound and MSCT each provided 100% sensitivity for tumor detection, but the sensitivity of other end points varied. Ultrasound was favored for tumor staging (89% versus 79%) and for diagnosis of local node involvement (82% versus 76%). CT was better in diagnosing distant node involvement and other metastases (65% versus 92%).

MSCT offers a field-of-view depth superior to endoscopic ultrasound for staging and detection of local disease and distant lymph node metastases, but it isn't perfect. Differentiation between T1 and T2 stages using the bowel distention-plus contrast technique is difficult, if not impossible. And MSCT's spatial resolution is still inferior to endoscopic ultrasound.