Masahiro Komori MD, Presenter: Nothing to Disclose

Satoshi Kawanami MD, Abstract Co-Author: Nothing to Disclose

Daisuke Tsurumaru, Abstract Co-Author: Nothing to Disclose

Kiyohisa Hiraka, Abstract Co-Author: Nothing to Disclose

Tsuyoshi Tajima MD, PhD, Abstract Co-Author: Nothing to Disclose

Hiroshi Honda MD, Abstract Co-Author: Nothing to Disclose

We create a new volume rendering technique " CT gastrography-wall carving image (WC) " to visualize enhancement in the gastric wall distinctly. To estimate diagnostic performance of WC adjunct to axial CT (ACT), multiplanar reconstruction (MPR), and virtual endoscopy (VE) for detection of early gastric cancer (EGC) with operation record and optical endoscopic findings as reference standard.

39 patients with 43 EGCs underwent preoperative examinations. After administration of intravenous contrast material and oral effervescent agent, MDCT data was transferred to a computer workstation to reconstruct MPR, VE, and WC. Two gastrointestinal radiologists independently reviewed images under three different conditions as follow: term 1: ACT only, term 2: ACT, MPR and VE, term 3: ACT, MPR, VE and WC for detection of EGC. Diagnostic performance of each conditions was analysed using a confidence level scoring system, and receiver operating characteristic (ROC) curves were generated for each observer. Interobserver agreement was calculated by using weighted-κ statistics. In addition, we also compared the morphological findings between detectable group (DG) and undetectable group (UG) according to the result of term3.

The best diagnostic performance and interobserver agreement were obtained in term 3. The AUC of both observers at term 1, 2, and 3 was 0.63 and 0.57, 0.73 and 0.73, and 0.84 and 0.76, respectively. Interobserver agreement improved from fair at term 1, moderate at term 2, substantial at term 3. 27EGCs (mucosal,15; submucosal,12) determined DG, whereas 14 EGCs(mucosal,8; submucosal,6) determined UG at term3. Two suspected EGCs were excluded because of false positive lesions. DG (median: 27mm) was larger than UG (median: 16mm) with a statistically significant difference (p<0.05). There was no significant difference between DG and UG with respect to morphological type and depth of invasion.

Addition of WC to conventional CT imaging improved diagnostic accuracy and interobserver reproducibility for detection of ECG. The authors believe that WC good alternative to visualize localized enhanced tumors in the gastric wall.

CTG-WC may become a helpful diagnostic tool for detection, prediction of histological prognostic factors, assessment of post neoadjuvant chemotherapy in patient with gastric cancer.

Komori, M, Kawanami, S, Tsurumaru, D, Hiraka, K, Tajima, T, Honda, H, Contrast-enhanced MDCT Gastrography for Detection of Early Gastric Cancer: Initial Assessment of “CT Gastrography Wall Carving Image”—A Novel Volume Rendering Technique  .  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012406.html