Multidetector CT of Locally Invasive Advanced Gastric Cancer: Value of Oblique Coronal Reconstructed Images for the Assessment of Local Invasion

Abstract

Purpose: To evaluate the diagnostic value of oblique coronal reconstructed CT images to determine the local invasion of advanced gastric cancer (AGC). Materials and Methods: Thirty-four consecutive patients, who were suspected to have locally invasive advanced gastric cancer (more than T3 stage) on a preoperative MDCT scan and underwent a diagnostic or curative laparotomy, were enrolled in this study. Two reviewers performed an independent blind review of three series of MDCT images in random order; axial (AXI), conventional coronal (CCI), and oblique coronal (OCI) (parallel to long axis of gastric body and pancreas) images. In assessing the local invasion, the reader’ confidence for the local invasion of AGC was graded using a five point scale (1 = definitely negative, 5 = definitely positive: T4). With surgical findings and histopathological proofs as reference standards, the diagnostic performance of the three different plans of CT images was employed for the verification of local invasion of AGC on a preoperative CT scan using the receiver operating characteristic (ROC) method. Agreements between the two reviewers were analyzed using weighted kappa statistics. Results: In 19 out of 34 patients, local invasion was confirmed surgically or histopathologically (13 pancreas invasion, 6 liver invasion, 4 major vascular invasion, 3 colon and mesocolon invasion, and 2 spleen invasion). The diagnostic performance of OCI was superior to AXI or CCI in the local invasion of AGC. The differences in the area under the curve of AXI (0.770 0.087, 0.700 0.094), CCI (0.884 0.058, 0.958 0.038), and OCI (0.954 0.050, 0.956 0.049), were statistically significant for both reviewers. Inter-observer agreement was excellent for OCI (= .973), which was greater than CCI (= .839), and AXI (= .763). Conclusion: On a CT scan, OCI might be a useful imaging technique in evaluating locally invasive advanced gastric cancer.