COMPUTED TOMOGRAPHY IMAGING PRESENTATION IN THORACIC HYDATID CYSTS.

Abstract

Hydatid cysts are widespread zoonosis that originate from the larval embodiment of the Echinococcus and can be frequently found in the lung and liver parenchyma, in addition, they emerge in various atypical locations in the thoracic cavity such as the mediastinum, its vascular compounds and the heart, the interlobar fissures, the pleural and pericardial space, as well as the structures of the chest wall and the diaphragm. Computed tomography as one of the most utilized instruments of radiology imaging has a crucial role in the diagnosis of hydatid cysts, depiction of their exact size and location, as well as estimation of impending complications. The aim of this pictorial review is to offer full scale understanding of the recurrent imaging findings in thoracic hydatid disease as well as to display some rare, extra parenchymal involvement and a summary of the complications and differential diagnosis. We did an in depth analysis of 55 chest CT scans of patients with thoracic hydatid cysts from North Macedonia and all patients underwent a contrast enhanced chest CT according to appropriate diagnostic protocol on a 16- slice Somatom GO computed tomograph (Siemens Healthineers, USA). Hydatid cysts in all 55 patients were divided by location and appearance in two by two categories, uncomplicated parenchymal and extra parenchymal, and complicated or ruptured parenchymal and extra parenchymal cysts. Uncomplicated parenchymal hydatid cysts were presented by well circumscribed, low attenuating, homogenous lesions with smooth walls of varying thickness, whereas complicated or ruptured hydatid cysts could be categorized in two forms, contained or complete rupture. The most frequent imaging findings were the air crescent sign, waterlily sign and dry cyst sign. Uncommon extra parenchymal hydatid cysts’ locations were the mediastinum, pericardium and the diaphragm. Computed tomography plays an important diagnostic role in common thoracic hydatid cysts and aids in the evaluation of rare and complicated cases.