The present study aims to analyze the characteristics of F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) for cerebral alveolar echinococcosis (CAE)

Echinococcosis is a serious zoonotic disease caused by Echinococcus parasiting in the body of intermediate hosts, such as humans and some animals. Echinococci that cause human echinococcosis mainly include 2 kinds: Echinococcus granulosus (E granulosus) and Echinococcus multilocularis (E multilocularis). 

In the present study, 25 patients with cerebral alveolar echinococcosis (CAE), who were treated in our hospital from July 2012 to October 2017, were enrolled. Twenty-five CAE patients underwent F-FDG PET/CT, and the diagnosis was confirmed by clinical and surgical pathology.

F-FDG SUVmax for lesions

The F-FDG PET/CT results were subject to visual and semiquantitative analysis, and the difference in F-FDG SUVmax for lesions among the 3 types of CAE was evaluated.

In the 25 CAE patients, 62 lesions were detected by F-FDG PET/CT, and these lesions were classified into 3 types, according to the characteristics of the lesion's uptake of F-FDG on PET images: type I, 17 lesions, FDG was concentrated into a mass radioactive distribution in the CAE foci; type II, 28 lesions, FDG presented an annular concentrated radioactive distribution around the CAE foci; type III, 17 lesions, FDG in the CAE foci presented a radioactive distribution with defects and sparse areas.

The difference in F-FDG SUVmax between type I and type II CAE was not statistically significant (P > .05), the difference in F-FDG SUVmax between type I and type III CAE was statistically significant (P < .001), and the difference in F-FDG SUVmax between type II and type III CAE was statistically significant (P < .001).

The F-FDG PET manifestations of CAE are classified into 3 types. Both type I and type II may have invasive activity, while the lesions of type III CAE show that the focus is relatively stable or at a stationary phase. If there is no definite alveolar echinococcus focus in other sites, these patients can temporarily delay the treatment.

It is recommended that the patient should undergo whole-body PET/CT once a year to dynamically observe the bioactivity and size of type III CAE lesions and assess the presence of new echinococcus lesions in the rest of the body.

The dynamic observation of biological active areas with different energy metabolism in CAE lesions can not only be used as a guide in determining the treatment regimen but also provide new clinical significance in recognizing the infiltration mechanism of CAE to the surrounding tissues.