Clinical Research On Boundary Of Hae With ¹⁸F-FDG And Its Biological Characteristics

Objective: To explore the biological activities of marginal zone of hepatic alveolar echinococcosis(HAE) from several aspects, including the imaging findings of 18F-FDG PET/CT and pathological results, assessment on the activity of the liver via autotransplantation at the end-stage of HAE, as well as the radioactive distribution at the edge of the lesions before and after treatment with albendazole liposomes. Methods: 1) PET/CT imaging was used on a total of 107 cases of HAE patients(107 lesions) from the First Affiliated Hospital of Xinjiang Medical University between July 2011 and July 2015, including 59 male patients and 48 female patients, aging 51±24 years. After analysis on the imaging findings of 18F-FDG PET/CT for HAE, radioactive uptakes of the internal lesions and the marginal zone as well as the adjacent liver tissues were compared, in addition, SUVmax values were measured and analyzed. All patients were given surgical resection, pathological examinations and immunohistochemical examination. Fourfold table assay was carried out on proliferation and infiltration zone as well as dormant zone at the marginal lesions of HAE showed by 18F-FDG PET/CT; 2) Specimens were taken from the marginal lesions of the postoperative biopsy specimens of the 107 patients for HE staining, CD34 staining and MASSON staining, to analyze the correlation of SUVmax at the marginal zone with microscopically inflammatory cells, microvascular density and the fibrosis area; 3) A total of 20 patients with end-stage HAE were selected from the First Affiliated Hospital of Xinjiang Medical University, all of whom were treated by in-vitro liver resection and liver autotransplantation. Standard collection was adopted with 18F-FDG PET/CT. The patients were given 18F-FDG PET/CT imaging before and after the operation. Biological marginal of the lesions was drawn before the operation. The number of the concentrated lesions was recorded and their maximum SUV(SUVmax) values were measured to compare with the pathological results. 18F-FDG PET/CT imaging was also performed in 1 month, 3 months and 6 months after operation, respectively. SUVmax of the transplanted liver was measured for statistical analysis. Another 37 patients with HAE were selected and given PET/CT imaging for SUVmax of the marginal lesions before routine medication with albendazole liposomes(10mg/d.kg). PET/CT imaging was performed again 6 months later, to measure the SUVmax of the marginal lesions. Results: 1) There was no obvious distribution of radioactive drug in the inner lesions of HAE, with SUVmax of 0.59±0.55. And the radioactive distribution at the marginal lesions was or increased to different extent, or not obvious, with SUVmax of 5.26±3.44. Moreover, the radioactive distribution of the liver tissues around the lesions was uneven, with SUVmax of 1.79±0.53. There were statistically differences in SUVmax between the inner and marginal lesions, between the inner lesions and surrounding liver tissues, and between the marginal lesions and surrounding liver tissues(P<0.05). Diagnostic fourfold table assay on proliferation and infiltration zone as well as dormant zone at the marginal lesions of HAE by 18F-FDG PET/CT and the corresponding marginal by pathological examination showed that the diagnostic sensitivity was 82.89%(63/76), the specificity was 61.2%(19/31), the accuracy was 76.6%(82/107), positive predictive value was 84.0%(63/75), and negative predictive value was 59.37%(19/32); 2) There was significantly negative correlation between SUVmax at the marginal lesions and fibrosis area in 107 patients(r=-0.79, P<0.001). Type I referred to the marginal lesions of uneven mass radioactive distribution and concentration zone. When the SUVmax was 7.00±2.47, the concentration degree was positively correlated with microvascular density(r=0.87, P<0.05). Type II referred to the marginal lesions of even ring radioactive distribution and concentration zone. When the SUVmax was 3.69±0.70, the concentration degree was positively correlated with microvascular density(r=0.76, P<0.05). Type III referred to the marginal lesions of spare radioactive distribution or defect zone. When the SUVmax was 1.08±0.22, there was no correlation between the concentration degree and the microvascular density(P>0.05). In addition, SUVmax at the marginal zone was also affected by granuloma of different sizes around the vesicle. It was pathologically expressed as aggregation of a large amount of immune cells and infiltration of the tissues, also neovascularization, followed by necrosis, fibrosis and calcification; 3) Marginal lesions of HAE had obvious uptake of radioactive drug, with biological activities. SUVmax of the survival liver was 2.95±0.47 in 1 month after liver autotransplantation for HAE, 2.21±0.17 in 3 months, and 2.06±0.11 in 6 months. Compared with SUVmax of the normal liver(1.93±0.12), there was statistical differences in data of the postoperative 1 month but no obvious statistical differences in data of the postoperative 3 month and 6 month. All of the patients with liver autotransplantation for HAE were followed up for 1~39 months. No metastasis of the extrahepatic organ was found in any case. Conclusion: 1) Whole body 18F-FDG PET/CT imaging for HAE not only can detect the location, size and number of the lesions but also can judge the marginal zone of the lesions based on the characteristics and degrees of the radioactive lesions at the marginal lesions of HAE, thus providing better imaging basis for clinical surgery for HAE; 2) Different SUVmax values of 18F-FDG PET/CT imaging can mirror the degree of fibrosis at marginal lesions, the microvascular forming condition and distribution of inflammatory cells to a certain extent. And there is a one-to-one correspondence between SUVmax values at marginal lesions and the microvascular density and degree of fibrosis, which provides a pathological basis for marginal lesions of AE. 18F-FDG PET/CT imaging is the most effective method to determine the boundary of HAE, thus more efficiently guiding the clinical work; 3) 18F-FDG PET/CT imaging can effectively select indications and surgical timing of liver autotransplantation for HAE, so as to early find postoperative recurrence of liver autotransplantation or metastasis lesions. It is also of important clinical value to determine the metabolic activity of survival liver after liver autotransplantation. Radioactive uptake(SUVmax value) at marginal lesions of HAE showed by 18F-FDG PET/CT can be used as evaluation index for curative effects on HAE.