Study On CT Image Quality And T Staging Of Gastric Cancer By Energy Spectrum CT Single Energy Technique Combined With ASIR

Background:Gastric cancer is a major global public health problem and a serious threat to human health.The number of people dying from gastric cancer in China accounts for more than 40% of the global total every year.There are a variety of treatment methods for gastric cancer,and it is of great significance to select the best treatment method for patients.The choice of treatment methods for gastric cancer mainly depends on the specific situation of patients diagnosed with gastric cancer,including the infiltration of tumor lesions on the gastric wall,lymph node metastasis and distant metastasis.Surgical treatment is often used for early gastric cancer,and the most commonly used surgical method is total gastrectomy combined with D2 lymph node dissection.Most of the patients with early gastric cancer does not show obvious symptoms,only a minority of patients characterized by abdominal pain,abdominal distension,such as mild digestive tract irritation,due to the easy confused with gastric ulcer,gastritis and other digestive tract diseases,to the attention of the patient,lead to early gastric cancer clinical diagnosis rate is low,so that the majority of patients progress for gastric cancer,Only when obvious clinical symptoms such as emaciation and severe pain in the upper abdomen appear do you choose to seek medical treatment and make a diagnosis,but at this time,the best operation window has often been missed.Therefore,accurate staging of gastric cancer is a key step to evaluate the overall survival rate and adjust treatment methods.Insufficient staging of gastric cancer may lead to unnecessary open surgery,while excessive staging will hinder the operation of curable patients and delay treatment.Although advanced gastric cancer patients can also be treated with systemic chemotherapy,surgical resection,immunotherapy and traditional Chinese medicine therapy,the prognosis and survival rate are far less than early gastric cancer.In conclusion,early detection,early diagnosis and early treatment are still the best methods to improve prognosis and survival rate for patients with gastric cancer.Which various examination methods of gastric cancer,especially the imaging examination method is put forward the challenge,in recent years,great progress has been made in science and technology in medicine,the birth of a new imaging method that energy spectrum CT,the imaging methods and common CT are quite different,mainly adopts single bulb double voltage instantaneous switch gain spectrum imaging,It can obtain clearer images and reduce the radiation dose,bringing hope and possibility for the diagnosis and treatment of early gastric cancer patients.Objective: 1.Compare the image quality of energy spectrum CT single energy imaging with conventional CT scan,and study the significance of energy spectrum CT single energy imaging combined with ASIR technology in CT image display of gastric cancer.2.To evaluate the value of energy spectrum CT in the diagnosis of T staging of gastric cancer.Methods: Twenty-five planned gastric cancer patients in the First Affiliated Hospital of Henan University of Science and Technology from November 2020 to July2021 were prospectively collected.Revolution CT was used to scan gastric cancer patients,and filtering back projection reconstruction algorithm(FBP)and 40-100 ke V7-group single-energy reconstruction were performed on all patients.The most obvious sites of gastric cancer lesions were selected for arterial phase reconstruction images in each group.CT values of tumor lesions in arterial phase and venous phase were measured and the corresponding contrast noise ratio(CNR)and signal to noise ratio(SNR)were calculated.Subjective image quality score was performed according to the scoring criteria.The best single energy group was selected and combined with10%-100%ASIR for reconstruction,respectively.CT values of tumor lesions at the same location in arterial and venous phases were measured by the same method,and corresponding contrast noise ratio(CNR)and signal to noise ratio(SNR)were calculated.Subjective image quality was scored by two professional radiologists according to the scoring criteria.According to the optimal quality image of gastric cancer obtained by statistical analysis,two professional radiologists conducted Tstaging diagnosis of gastric wall infiltration according to the lesions.In case of disagreement between the two physicians,another senior radiologist will review the film for judgment.Using pathological examination results as the "gold standard",the diagnostic value of energy spectrum CT combined with ASIR in T staging of gastric cancer was analyzed.Results: At 70 ke V,CNR and SNR were 2.52±1.38,7.71±1.49,2.52±1.31 and8.14±3.27,respectively,which were higher than those in FBP group and other single energy groups,and the difference was statistically significant(P < 0.05).In 70 ke V combined with ASIR reconstruction,CNR and SNR in 50%ASIR group were3.87±1.48,9.94±2.51,1.96±1.14 and 6.93±2.61,respectively,higher than those in other groups,the difference being statistically significant(P < 0.05).There were statistically significant differences in subjective evaluation of image quality between groups(P < 0.05).The sensitivity of SPECTRAL CT in diagnosing T1,T2,T3 and T4 staging was 66.67%,60.00%,77.78%,100.00%,and the specificity was 94.74%,85.00%,93.75%,95.00%,respectively.The accuracy was 88.00%,80.00%,88.00%,96.00%,and the Kappa value of pathological diagnosis was 0.76,0.84,0.88,0.96,respectively.Conclusion: 1.Energy spectrum CT single energy imaging combined with ASIR reconstruction can improve the CT image quality of gastric cancer and better display effect on fine structures of gastric cancer lesions.Among them,CT images obtained by using 70 ke V single energy combined with 50% ASIR reconstruction have the best quality and higher clarity,which is of great help in the diagnosis of T stage of gastric cancer.2.Energy spectrum CT has excellent diagnostic value in preoperative T staging of gastric cancer,which is highly consistent with pathological diagnosis and can provide better diagnostic information for the clinic.