Evaluating the diagnostic accuracy of dynamic CT transmural sign for T staging of gastric cancer compared to conventional CT criteria.

[BACKGROUND] To retrospectively evaluate the diagnostic performance of pre-procedural multidetector computed tomography (MDCT) using dynamic CT transmural (CTTM) criteria for T staging of gastric cancer.

[METHODS] This retrospective study enrolled 116 patients who underwent three-phase dynamic MDCT and subsequently received endoscopic treatment or surgery. The positive CTTM sign was defined as a new diagnostic criterion for this study. Two radiologists independently reviewed the CT images, categorizing patients into five groups: T1b sm1, T1b sm2/3, T2, T3, and T4. The diagnostic performance of the new criterion was assessed against pathological results as the gold standard. Sensitivity, specificity, accuracy, and positive and negative predictive values for each T stage were compared to those of conventional CT.

[RESULTS] Dynamic CTTM criteria demonstrated higher overall diagnostic accuracy (Reviewer 1: 88.9%, Reviewer 2: 91.4%) for T staging compared to conventional CT criteria (75.9%). Reviewer 1 accurately staged T1b in 85.3% of patients, T2 in 87.7%, T3 in 94.1%, and T4 in 98.3%. Reviewer 2 achieved T1b accuracy of 87.9%, T2 of 89.2%, T3 of 94.9%, and T4 of 98.3%. The dynamic CTTM criteria effectively subdivided T1b into T1b sm1 (87.2% and 88.1%) and T1b sm2/3 (84.6% and 86.2%). Dynamic CTTM criteria exhibited higher under-staging rates, while conventional criteria showed higher over-staging rates.

[CONCLUSIONS] Dynamic CTTM criteria demonstrated superior accuracy in T staging of gastric cancer and reasonable effectiveness in subdividing T1b stages into T1b sm1 and T1b sm2/3.