Serial CT findings of Paragonimus infested dogs and the Micro-CT findings of the worm cysts.
OBJECTIVE
To investigate the serial CT findings of Paragonimus westermani infected dogs and the microscopic structures of the worm cysts using Micro-CT.


METHODS
This study was approved by the committee on animal research at our institution. Fifteen dogs infected with P. westermani underwent serial contrast-enhanced CT scans at pre-infection, after 10 days of infection, and monthly thereafter until six months for determining the radiologic-pathologic correlation. Three dogs (one dog each time) were sacrificed at 1, 3 and 6 months, respectively. After fixation of the lungs, both multi-detector CT and Micro-CT were performed for examining the worm cysts.


RESULTS
The initial findings were pleural effusion and/or subpleural ground-glass opacities or linear opacities at day 10. At day 30, subpleural and peribronchial nodules appeared with hydropneumothorax and abdominal or chest wall air bubbles. Cavitary change and bronchial dilatation began to be seen on CT scan at day 30 and this was mostly seen together with mediastinal lymphadenopathy at day 60. Thereafter, subpleural ground-glass opacities and nodules with or without cavitary changes were persistently observed until day 180. After cavitary change of the nodules, the migratory features of the subpleural or peribronchial nodules were seen on all the serial CT scans. Micro-CT showed that the cyst wall contained dilated interconnected tubular structures, which had communications with the cavity and the adjacent distal bronchus.


CONCLUSIONS
The CT findings of paragonimiasis depend on the migratory stage of the worms. The worm cyst can have numerous interconnected tubular channels within its own wall and these channels have connections with the cavity and the adjacent distal bronchus.
Lee
Chang Hyun
CH
Department of Radiology and the Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Korea.
Im
Jung-Gi
JG
Goo
Jin Mo
JM
Lee
Hyun Ju
HJ
Hong
Sung-Tae
ST
Shen
Cheng Hua
CH
Chung
Doo Hyun
DH
Son
Kyu Ri
KR
Chang
Jung Min
JM
Eo
Hong
H
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D003560:Cysts / Q000000981:diagnostic imaging* / Q000469:parasitology*; D018450:Disease Progression; D004285:Dogs; D005260:Female; D005500:Follow-Up Studies; D006872:Hydropneumothorax / Q000469:parasitology; D007472:Iohexol / Q000031:analogs & derivatives; D008168:Lung / Q000000981:diagnostic imaging / Q000469:parasitology; D008297:Male; D015588:Observer Variation; D010237:Paragonimiasis / Q000175:diagnosis* / Q000469:parasitology; D048492:Paragonimus westermani / Q000254:growth & development / Q000302:isolation & purification; D010996:Pleural Effusion / Q000469:parasitology; D011856:Radiographic Image Enhancement / Q000379:methods; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide