| Part one:Value of virtual gastroscpy in detecting gastric cancerObjective:The aim of this study was to investigate value of virtual gstroscogrphay (VG) with multi slice spiral CT (MSCT) in detection of gastric cancer.Materials and Methods:This study was approved by the institute ethic committee of clinical study and written informed consent was obtained in all the patients. Sixty-seven consecutive patients with gastric cancer, which was confirmed or highly suspected by biopsy through gastro copy, received CT scanning after adequate stomach distention using gas-producing powder by a 16-slice MSCT and VG was obtained. Two experienced radiologists blinded to gastroscopy findings, evaluated the transverse and VG images, respectively. Disagreements were resolved in consensus. Differences of detection rate of VG and transverse images for primary tumors were assessed with the McNemar exact test. Statistical significance was inferred at P<.05.Results:All 67 patients,VG detected tumors in 61 patients with detection rate of 91.04%, while the detection rate of transverse images was 83.58%. This difference was not statistically significant (P=0.227). In 23 patients with primary tumors size<3CM, detection rate of VG was 86.96%, which was higher than the transverse images'56.52% with statistical significance(P=0.016).Conclusion:VG can reveal primary gastric cancer in the same way as gastroscopy. In small size lesions, its detectability is superior to that of transverse images. VG might be a promising modality for gastric cancer detection.Part two:Application of CT angiography in preoperative assessment ofgastric cancerObjective:The aim of this study was to assess the usefulness of MSCTA in preoperative evaluation of gastric cancer.Materials and Methods:This study was approved by the institute ethic committee of clinical study and written informed consent was obtained in all the patients. Sixty-seven consecutive patients with gastric cancer, which was confirmed or highly suspected by biopsy through gastroscopy, were enrolled in this study. Gastric distension was achieved by using gas-producing powder and 500-1000 ml water. Triple-phase Scanning of MSCT was performed with Bolus- Tracking and automated triggering technique after intravenous administration of 100mL of contrast materials (Iopamidol, Ultravist 370) by power injector at a rate of 3-4 ml/s. CT angiograms were reconstructed at a CT workstation by using volume rendering (VR) and maximum intensity projection (MIP) techniques, especially the vessels with closely anatomy relationship of tumors. CT findings were compared to intra-operative findings and/or pathological findings.Results:CTA could visualize all the LGA and the RGA at a percentage of 52.24%. It also revealed 12 related vessels anatomies. At the sixty-one patients who received operation, the anatomy information showed excellent concordance with the surgical finds.Conclusion:CTA can reveal the main arteries around the stomach, especially those with closely anatomical relationship to the primary gastric cancer, which may affect operation decision and performation. Adding CTA in the protocol of gastric CT examination may improve its cost effectiveness.Part three:Role of multiplanar reformation with multi slice CT in preoperative T and N staging of gastric cancer with Histopathologic CorrelationObjective:To investigate value of multi-planer reformation (MPR) with multi slice spiral CT (MSCT) for preoperative T-and N staging of gastric cancer.Materials and Methods:This study was approved by the institute ethic committee of clinical study and written informed consent was obtained in all the patients. Sixty-seven consecutive patients with gastric cancer, which was confirmed or highly suspected by biopsy through gastroscopy, was achieved Gastric distension using gas-producing powder and 500-1000 ml water. Triple-phase Scanning of MSCT was performed as determined with Bolus-Tracking and automated triggering technique after intravenous administration of 100mL of contrast materials (Iopamidol, Ultravist 370) by power injector at a rate of 3-4 mL/s. Sixty-one patients who underwent operations were enrolled in this study. MPR images were obtained by a radiologist to choose the optimal plane which could better depict the lesion and its relationship with adjacent organs and tissue using an interactive real-time manner. Two experienced radiologists evaluated T and N staging on the transverse and MPR images in consensus. T and N staging on CT was correlated with the histopathologic results. Differences in accuracy of transverse and MPR images for T and N staging were assessed with the McNemar exact test. Statistical significance was inferred at P<.05. A surgeon was invited to evaluate which of (?)ansverse and MPR images would transport information of CT report efficient.Results:Detection rate of primary tumors with transverse and MPR images were 90.16%(55 of 61),93.44%(57 of 61), respectively. The accuracy for MPR images in assessment of tumor invasion of the gastric wall (T staging) was 86.89%(53 of 61), which was higher than that for transverse images [63.93%(39 of 61)] (P=.001). Overall accuracy for lymph node (N) staging was 70.49%(43 of 61) with MPR images and 62.30%(38/61) with transverse images, respectively. This difference was not statistically significant (P=0.125). The surgeons preferred MPR images to transverse images about transporting CT report information in all 61 patients.Conclusion:Although not improving the accuracy for lymph node (N) staging, MPR images of multi slice spiral CT can improve the accuracy of local invasion of gastric cancer(T staging), and facility in information transfer between radiologists and relative clinicians. It is worth recommending at clinical application. |
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