The Application Studies Of Evaluation On Preoperative Staging And Grading Of Gastric Cancers With Spectral CT

Part One:The Studies of Preoperative Staging of Gastric Cancer with Spectral CTPurpose To explore the clinical value of gemstone spectral imaging (GSI) with spectral CT in evaluating preoperative T stage and N stage of gastric cancer. Methods Spectral parameters of 50 patients with advanced gastric cancer underwent preoperative dual-phase spectral CT scan (arterial, venous phase) were analyzed retrospectively, including 29 cases with fatty infiltration around the stomach, all cases were proved by pathological findings. CT features of Normal stomach, gastric lesions, fat around the stomach and regional lymph nodes were analyzed and were compared with pathological findings. [1] T stage:The spectral parameters of gastric lesions and distal normal stomach wall, infiltration fat and normal fat were measured. The different single-spectral CT values of 40-140keV (interval 10 keV), iodine (water) concentration, water (iodine) concentration were compared. Data were analyzed statistically by independent-samples T-test. [2] N staging:Two senior abdominal radiologists analyzed all the cases by double-blind method. The accuracy of spectral CT measure methods(the spectral curve of lymph node and gastric lesions were observed, identical or similar to those curve shape were thought of metastatic lymph nodes) and conventional CT measure methods (the size, long and short diameter and CT value of lymph node were observed)in evaluating metastatic lymph nodes were compared. When the diagnosis of two radiologists were different, to discuss in order to determine the final results. Results [1] In artery and venous phase, there were significant difference in the single-spectral CT values of 40-100 keV (P<0.05) between gastric lesions and normal gastric wall these in gastric lesions were higher than normal gastric wall; Significant differences were found in the iodine concentrations between the gastric lesions and normal stomach, gastric lesions were higher than normal stomach (P<0.05). [2] Invaded fat were significantly different from normal fat in the single-spectral CT values of 40-140 keV in arterial and venous phase (P<0.05), and that in invaded fat were higher than normal fat; Iodine concentrations of invaded fat were all significantly higher than normal fat in both arterial and venous phase (P<0.01). [3] The accuracy of spectral CT method to assess N stage of gastric cancer was 74%, which was significantly higher than traditional CT method (62%) (χ2=3.737, P<0.05). Conclusion Quantitative parameters of spectral CT is helpful in differentiating identify gastric cancer from normal stomach wall and invaded fat from normal fat, and improving the accuracy in judging the metastatic lymph nodes. So the spectral CT can provide quantitative evidence in preoperative evaluating T staging and N staging of gastric cancer.Part Two:The Studies of Evaluation on Differentiation of Gastric adenocarcinoma with Spectral CTPurpose To explore the clinical value of gemstone spectral imaging (GSI) with spectral CT in evaluating in vivo on different differentiation state of advanced gastric adenocarcinoma. Methods 66 patients with advanced gastric adenocarcinomas confirmed by pathology were analyzed retrospectively. All patients underwent plain CT and triple-phases enhanced CT with CT spectral imaging mode(Discovery CT 750HD, GE Healthcare). The single-spectral CT values of 40-140keV (interval 10keV), slope of spectral curve, iodine (water) concentration, normalized iodine concentration (NIC) and the added value of iodine concentration in each enhanced phase were analyzed, and the correlation between parameters of spectral CT with different differentiation of gastric adenocarcinomas were evaluated. Results In plain scan, there were significant difference in the single-spectral CT values of 40-50keV between different degree of differentiation of gastric adenocarcinomas (P<0.05); there were no significant difference in other single-spectral CT values, slope of spectral curve, iodine concentration and NIC between different degree of differentiation (P>0.05). In triple-phase enhanced CT scan, Significant differences were found in The single-spectral CT values of 40-140keV (interval 10keV), slope of spectral curve, iodine (water) concentration, NIC and the added values of iodine concentration in each enhanced phase between different degree of differentiation of gastric adenocarinomas(P<0.01), these parameters in poorly differentiated adenocarinoma >moderately differentiated adenocarinoma >highly differentiated adenocarinoma, and Significant differences were noted in vein phase. Conclusion The multi-parameter analysis of spectral CT can contribute to evaluating in vivo differentiated degree of advanced gastric adenocarcinoma.