Hydatid Disease of the Central Nervous System: Imaging Characteristics and General Features

Background; Hydatid disease primarily affects the liver and typically demonstrates characteristic imaging findings. Secondary involvement due to hematogenous dissemination may be seen in almost any locations, e.g., lung, kidney, spleen, bone and central nervous system (CNS). To review the different aspects of hydatidosis of the CNS briefly and discuss the pathognomonic features and rare varieties of radiological findings useful in preoperative diagnosis of the disease in the human CNS. Material & Method; In a retrospective study, the records of almost 100 cases of CNS hydatidosis were analyzed. The available images were reviewed by independent observers, either a radiologist or a neurosurgeon, and reported separately. Results; In skull X-ray films, nonspecific changes denoted increased intracranial pressure, skull asymmetry and curvilinear calcification in rare instances. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated the round or oval, well-defined cystic mass with an attenuation or signal intensity similar to that of cerebrospinal fluid, with no associated perifocal edema, and no contrast enhancement as the pathognomonic findings of brain hydatidosis. Similar findings were detected in hydatid cysts involving the orbit, spinal column and spinal cord with some variations. Such findings as mild perifocal edema, nonhomogenous contrast enhancement, non-uniform shapes, calcification and multiplicity or septations have been the atypical radiological findings. Conclusion; In endemic areas, familiarity with typical and atypical radiological manifestations of hydatid disease of the CNS, will be helpful in making prompt and correct preoperative diagnosis leading to a better surgical outcome.