The Research Of Imaging Features And Blood Supply Guilded By Dual Energy CT In Hepatic Alveolar Echinococcosis

Objective: Through analyzing the imaging features of dual energy computer temograghy(DECT) and traditional CT in hepatic alveolar echinococcosis(HAE) lesions, and comparing with histopathology and 18-fluorodeoxyglucose positron emission tomography computed tomography(FDG-PET/CT), to investigate the clinical value of DECT to evaluate the characteristic and blood supply in HAE.Methods: 45 cases(30 men, 15 women; 39.7 ± 12.5 years) suffered from AE(HAE cases were confirmed by surgery and pathology) were retrospectively analyzed with complete DECT scan data were collected. All patients underwent three phases(Artery phase, portal venous phase and venous phase) contrast enhanced scan. Kept record the size, location, invasion findings. The CT patterns of the HAE lesions were classified into solid, pseudocystic, and mixed type. Through DECT imaging post processing reconstruction to obtain the serial function images of lesions. The various parameters in HAE lesions were measured and statistically compared with traditional CT. Twenty five patients from same group with surgery underwent abdominal DECT scan in dual-source mode. The DECT image data were processed with a software algorithm designed for evaluation of iodine distribution in marginal zone, solid, or cystic layer of the HAE lesions. The quantitative iodine concentration(QIC) in the various layers and types of HAE lesions were measured and statistically compared. The microvascular density(MVD) of the resected HAE were examined using CD34 immunohistochemical staining, and scored based on the percentage of positively stained cells and their intensity. Pearson’s correlation analysis was used to evaluate potential correlation between the DECT parameters and the MVD scores. In addition, 15 HAE cases with DECT and [18F]fluorodeoxyglucose positron-emissiontomography(FDG-PET) scan were compared in order to evaluate the metabolic activity of HAE. The quantitative parameters of QIC and SUV values were calculated. Consistency analysis and pearson’s correlation analysis were used to evaluate potential correlation between the DECT parameters and the FDG-PET.Results: A total of 53 HAE lesions(19 solid, 6 pseudocystic, and 28 mixed type) with average 87.6±50.7 mm lesion size were assessed. DECT detected more contrast enhance lesions(71.6%) than traditional CT(50.9). There was a significant difference in the QICs between various layers of the HAE in each of the three scan phases(p < 0.001). The QICs in the marginal zone were significantly higher than that in solid or cystic layers and liver parenchyma. No significant difference was found among the various CT patterns of the HAE. 65 ke V is the optimal monochromatic image with corresponding contrast noise radio(CNR) is 10.24±2.62. The spectrum curve showed special shape for HAE lesion. There were significant difference with curve slope between solid, margin zone of HAE and liver parenchyma. No significant difference with curve slope between imaging type in HAE. As for the comparison with(QIC) and(MVD). The QICs were significantly positive-correlation with the MVD scores in the marginal zone of the HAE lesions(r = 0.652, p < 0.05). When compared with PET-CT, FDG-PET identified increased metabolic activity in the corresponding lesions in 17 HAE lesions. Vascularization pattern of HAE lesions was visualized in 15 lesions(83.3%) by DECT. Positive FDG-PET findings with “hot pot” were also positive at DECTCT images which displayed as continuous or discontinuous ring-like enhancement with the 5~10mm thickness. The Kappa value of 0.673 indicate a good coincidence between DECT and FDG-PET in depicting the metabolic activity of HAE. There was high correlation between IC and SUV in marginal zone of HAE lesion during PVP(r=0.873,p<0.001).Conclusion:(1) DECT can provide more information using monochromatic images, iodine-based material decomposition images and the quantitative analysis of IC than traditional CT for the diagnosis of HAE.(2) The QIC measured with DECT is significantly correlated to the MVD scores in the marginal zones surrounding HAE. The DECT modality could be used clinically to evaluate the vascularity of HAE.(3) There was association between findings of metabolic activity in AE at FDG-PET and vascularized lesions of the liver returned by iodine quantification of spectral CT. DECT might be recommended as a cost-effective tool in the decision making to perform FDG-PET examination in assessing AE activity.