Radiologic localization of esophageal level: comparison with distance from incisor at endoscopy

The esophageal level on radiography was compared with that at endoscopy by establishing a relationship between the radiologic landmarks, i.e., the vertebral level and the distance from the carina, and the distance from the incisor at endoscopy.

Three hundred ninety spot films in 65 patients who underwent endoscopic retrograde cholangiopancreatography were analyzed. Six spot films were obtained for each patient, wherein the distances of the endoscopic tip were located at 20, 25, 30, 35, 40, and 45 cm from the incisors. On each radiogram, the vertebral level scores were measured as 1 to 12, for the location of the endoscopic tip at the levels of T1 through T12, respectively. When the endoscopic tip was located at the lower half of the vertebral body, 0.5 point was added to the vertebral level score and when the tip was noted at the upper half of it, no additional score was given. The distance between the endoscopic tip and the carina was also measured. Correlations of the distance of the endoscopic tip from the incisors on endoscopy with the vertebral body levels and the distance from the carina on radiography, accounting for patient height, were analyzed by multiple linear regression and equations were extracted.

Equation 1 for the vertebral level score (VL) for a given distance of endoscopic tip from incisor (DI) at a given patient height (H) was VL = 0.432DI - 0.048H + 0.099 (r2 = 0.968). Equation 2 for the distance from the carina (DC) for a given DI at a given H was DC = 0.957DI - 0.137H - 5.841 (r2 = 0.983). Two tables denoting radiologic VLs and DCs for given endoscopic DIs and patients' heights were generated using these equations.

Regressed equations and tables will enable radiologists to better localize the esophageal lesions that are seen at endoscopy, and vice versa.