An imaging diagnosis of cerebral paragonimiasis: CT and MR findings and correlation with ELISA antibody test

ABSTRACT

To evaluate the CT and MR findings of cerebral paragonimiasis (PW) and to assess the diagnostic value of the specific antibody test by enzyme-linked immunosorbent assay (ELISA) for PW, 55 CT scans and 13 MR images of 57 patients with cerebral PW were reviewed retrospectively, and correlated with the serum/CSF antibody levels. We divided the into three groups, early active(n=21), chronic(n=32), and combined stage (n=4), on the basis of CT/MR findings. In the group of early active stage the most common and characteristic findings was multiple, conglomerated, ring-like enhancing lesions in the unilateral cerebral hemisphere, which was seen in 52% on CT and 44% on MR. Other non-specific findings included a solitary ring-like or irregular enhancing lesions, ill-defined low density lesions without enhancement, localized hemorrhage with or without enhancing lesions. In the group of chronic stage there were multiple calcifications of various shapes, most commonly 1-2cm sized round shape, and associated encephalomalacia. MR was superior to CT in detecting hemorrhage and in characterizing the central contents of ring-shaped calcifications, while it was inferior to CT in identifying small calcifications. Antibody levels of serum and CSF were positive in 86% and 82% in early active group, and in 48% and 31% in chronic sgage respectively. The positive rate was significantly different between the two groups (P=0.001). CT/MR findings were characteristic in only approximately half the cases in early active cerebral PW which can be cured by traziquantel therapy. Therefore, antibody test by ELISA is recommended as a complementary tool, particularly in patients with non-specific imaging findings.