Imaging in 100 Patients of Thoracic Hydatid Disease Including Unusual Imaging Appearances

To evaluate the chest radiography and ct scan characteristics of pulmonaryhydatid disease (phd).patients and methods: one hundred patients (59 males and 41 females, age ranged from 9 to80 years) with surgically proven pulmonary hydatid cysts were studied. we reviewed clinicaland imaging findings including pa and lat chest roentgenograms and conventional ct of thechest. only 82 patients had ct scan in their files, but all had cxr. the radiological features(localization, diameter, architecture, density and other radiological signs and appearances)were determined.results: on cxr, 124 cysts were determined. in evaluation of 82 available ct scans, a total of112 cysts were detected. no cysts was detected on 5 ct scans. no discrete cyst was detectedon 10 cxrs: 4 patients, only consolidation; and 6 patients, only hydropneumothorax..the most frequent site of involvement was rll (29.6%). fifteen hydatid cysts appeared assolid masses on ct. fifty-seven cysts were ruptured cysts and 25 patients with rupturedcysts had hemoptysis (43.9%). thirty-eight percent of cysts had thin walls and 62% had thickwalls. sixty-four cysts were round in shape (55.7%). single cysts were seen in 63 patientswhile multiple cysts were seen in 37. median ct density of the cysts was 24 hounsfeild units(hu) (-18 to 84). there were 16 giant cysts (diameter . 10 cm) on ct. mean maximum andminimum dimensions of cysts were 5 cm and 4 cm on ct and 6.8 cm and 5.7 cm on cxr,respectively. on ct and cxr, water lily sign was seen in 18 and 22 patients, air-fluid levelin 12 and 17 patients, and crescent sign in 11 and 5 of patients, respectively. inverse crescentsign and calcification were not observed on cxrs, but each was reported on 4 ct scans. onct, 90% of cysts were smooth, 74 cysts were uniloculated and 9 were multiloculated. nineteenpercent of cysts were infected. other imaging findings included mediastinal shift, atelectasis,infiltration, pericystic lung reaction, chest wall involvement, and rib destruction.conclusion: cxr is helpful with diagnosis of intact cysts but fails to define entire morphologyof complicated cysts. ct imaging recognizes certain details not visible on radiography. in endemicregions like iran, atypical imaging presentations of complicated pulmonary hydatiddisease, such as solid masses, should be considered in differential diagnosis of pulmonarylesions