Abstract
Introduction: Although pulmonary hydatid cysts can be diagnosed on computed tomography (CT), sometimes
findings can be atypical. Other hypodense infective or neoplastic lesions may mimic
hydatid cysts. We proposed that magnetic resonance imaging (MRI) may act as a problem-solving
tool, aiding the definite diagnosis of hydatid cysts and differentiating it from its
mimics. The aim of this study is to assess the findings of pulmonary hydatid cysts
on CT and MRI and the additional contribution of MRI in doubtful cases. Materials and Methods: This is a retrospective study of 90 patients with suspected hydatid cysts. CT and
MRI findings were noted and role of MRI in diagnosing hydatid cysts and its mimics
was studied. Descriptive statistics for CT findings and sensitivity and specificity
of MRI were calculated using surgery or histopathology as gold standard. Results: Of the 90 patients with suspected pulmonary hydatid cysts, there were 52 true-positive
and 7 false-positive cases on CT. Commonest CT finding was unilocular thick-walled
cyst. In the 26 patients who had additional MRI, based on T2-weighted hypointense
rim or folded membranes, accurate preoperative differentiation of 14 patients with
hydatid cysts from 10 patients with alternate diagnosis was possible. There was one
false-positive and one false-negative case on MRI. Conclusion: Although hydatid cyst can be diagnosed on CT on most occasions, sometimes there are
challenges with certain mimics and atypical appearances. T2-weighted MRI can act as
a problem solving tool to conclusively diagnose hydatid cyst or suggest an alternate
diagnosis.
Keywords
Computed tomography - hydatid - magnetic resonance imaging - pulmonary
