Application Of Spectrum CT Quantitative Parameters In CTN Staging Of Advanced Gastric Cancer

Objective:To investigate the diagnostic value of energy spectrum CT quantitative parameters measurement and evaluation of cTN staging in advanced gastric cancer.Materials and methods:62 patients with advanced gastric cancer confirmed by operation and pathology were retrospectively analyzed.All patients underwent whole abdominal CT plain scan and energy spectrum dual phase dynamic contrast-enhanced examination within 2weeks before operation.cT staging:Analyze the CT spectrum characteristics of normal gastric wall,gastric cancer lesions,and perigastric fat space,and compare with pathological results.cT staging:Analyze the CT spectrum characteristics of normal gastric wall,gastric cancer lesions,and perigastric fat space,and compare with pathological results.cN staging:Energy spectrum CT observes the characteristics of lymph node energy spectrum curve and gastric cancer lesion curve.The curve shape is consistent or similar,and it is evaluated as metastatic lymph node.Two abdominal imaging diagnosticians and surgeons with more than 10 years of work experience matched the positions of the lymph nodes on the CT images with the positions of the pathological markers one-to-one,according to the gold standard of pathological results,the patients were divided into metastatic lymph node group and non metastatic lymph node group.Observe the CT value of each period,iodine concentration（IC）,normalized iodine concentration rate（NIC）,near-segment energy spectrum curve slope λHU40Ke V_<sup>90Ke V.Results:（1）General characteristics:62 patients with advanced gastric cancer with surgical and pathological results were included as the research subjects,including 47 males and 15 females,aged 43～77 years old,with an average age of 64.25±8.33 years old.10 cases in p T2,22 cases in p T3,30 cases in p T4.40 cases were in p N1～p N3 stage,93 lymph nodes corresponding to pathology and CT imaging were grouped into the metastatic lymph node group,22 cases were in p N0 stage,44 lymph nodes were detected on CT imaging were grouped into the non-metastatic lymph node group.（2）cT staging:The accuracy rates of energy spectrum CT for cT2,cT3,cT4 staging were 80.00%,81.82%,and 86.67%,respectively.cN staging:the accuracy of energy spectrum CT for cN0,cN1,cN2,cN3 was 54.55%,77.78%,84.62%,88.89%.（3）The single-energy CT 40 Ke V～140Ke V value,the slope of the energy spectrum curveλ_{HU40Ke V⁹0Ke V},IC value,and NIC value of the arterial phase and venous phase of advanced gastric cancer lesions were significantly higher than those of the normal gastric wall,and the difference was statistically significant（P<0.05）.T4a gastric cancer invaded the fatty space arterial phase,venous phase single energy CT 40～140Ke V value,energy spectrum curve slope(λ_{HU40Ke V⁹0Ke V}),IC value,NIC value are significantly higher than T3 stage,the difference is statistically significant（P<0.05）.（4）The characteristics of metastatic lymph nodes and non-metastatic lymph nodes:the short diameter was（14.10±5.31）vs（9.14±2.63）;the ratio of short to long diameter was（0.75±0.11）vs（0.55±0.11）;the CT value of arterial and venous phase was（72.72±21.70）vs（61.32±16.38）,（97.29±29.22）vs（63.43±20.21）;the IC of arterial phase was（16.83±6.14）vs（12.47±4.27）;IC in venous phase was（22.09±8.95）vs（13.89±5.06）,NIC in venous phase was（0.93±0.45）vs（0.49±0.23）,and the slope of energy spectrum in arterial and venous phase was（2.60±0.97）vs（1.91±0.84）,（3.52±1.11）vs（2.34±0.76）.The short diameter,ratio of short to long diameter,CT value,IC and NIC,slope of energy spectrum curve(λ_{HU40Ke V⁹0Ke V})of metastatic lymph node group were significantly higher than those of non-metastatic lymph node group,The differences between the two groups were statistically significant（p<0.01）.The ratios ofλ_{HU 40Ke V⁹0Ke V}between the arterial and venous metastatic and non-metastatic lymph node groups to the primary tumor were（1.34±0.72）vs（1.11±0.77）and（1.09±0.11）vs（0.74±0.09）,respectively.There was no significant difference in the arterial phase（P>0.05）,the difference in venous phase is statistically significant（P<0.01）.（5）Analysis of receiver operating characteristic curve of metastatic lymph nodes:short diameter,short and long diameter ratio,arterial phase CT value,venous phase CT value,arterial phase IC value,venous phase IC value,arterial phase energy spectrum slope,venous phase energy spectrum slope,the ratio of shorter length to diameter of the lymph node and the area under the venous phase IC curve（AUC）are 0.824,0.890,0.650,0.820,0.629,0.862,0.697,0.805,0.905,respectively;the corresponding thresholds were11.615（mm）,0.728,82.000（HU）,83.375（HU）,19.820（100ug/cm3）,18.290（100ug/cm3）,2.554,3.525,15.359,respectively;The sensitivities corresponding to each value are:0.634,0.796,0.312,0.677,0.280,0.710,0.538,0.559,0.860;The specificity corresponding to each value is 0.907,0.907,0.953,0.884,0.923,0.953,0.837,0.948,0.866.（6）Analysis of related factors of lymph node metastasis:lymph node metastasis of advanced gastric cancer is not related to the age of patients and the depth of tumor invasion,but related to gender,tumor size,degree of differentiation,Bormann classification,vascular tumor thrombus,short diameter of lymph node and IC value of venous phase.Multivariate regression model showed that gender,tumor size,degree of differentiation and IC in lymph node venous phase were related to lymph node metastasis.Conclusion:（1）Quantitative parameters of energy spectrum CT are valuable for Clinical evaluation of the accuracy of cT staging of advanced gastric cancer.（2）Spectrum CT can effectively diagnose whether the regional lymph nodes around the stomach are metastatic lymph nodes.The quantitative parameters of spectral CT in metastatic lymph nodes group are higher than those in non-metastatic lymph nodes group.There was no significant difference in lymph node length and NIC in arterial phase between the two groups.The diagnostic efficiency of combined lymph node short diameter>10mm and venous phase IC in the diagnosis of metastatic lymph nodes was the highest.The diagnostic efficiency of lymph node short diameter,arteriovenous phase CT value and arteriovenous phase energy spectrum curve slope was average,and the diagnostic efficiency of arterial phase IC value was the lowest.（3）Univariate analysis:the age of patients and the depth of tumor invasion（cT staging）were not related to lymph node metastasis of advanced gastriccancer,but the gender of patients,tumor size,tumor differentiation,Bormann classification,vascular tumor thrombus,short diameter of lymph nodes and IC value of lymph node venous phase could predict lymph node metastasis of gastric cancer.（4）Multivariate analysis:gender,tumor size,degree of differentiation and IC value in venous phase were related to the status of advanced gastric lymph node metastasis.Combined with Clinical data,spectral CT quantitative parameters and differentiation degree can be used as risk factors for predicting lymph node metastasis of advanced gastric cancer.