Migration: a notable feature of cerebral sparganosis on follow-up MR imaging

Cerebral sparganosis is a rare parasitic infection caused by sparganum, which can migrate in the brain. The purpose of this study was to demonstrate the migration of cerebral sparganosis and describe its patterns on MR imaging.

MR images of 14 patients with cerebral sparganosis treated from 2005 to 2011 were retrospectively reviewed. Diagnosis was made on the basis of a constellation of clinical history, laboratory tests, imaging findings, and histopathology. At least 3 MR imaging studies were performed for each patient during the follow-up period ranging from 12 to 38 months. Time interval, sites, enhanced pattern, and presumed routes of migration were evaluated.

Both the initial lesions and migrated ones exhibited the "tunnel" sign and multiloculated rim enhancement. Migration was detected between 4 and 18 months after the baseline MR imaging in 14 lesions (in 14 patients), while 3 of 14 lesions showed a second migration between 22 and 38 months. Nearly all migrations were limited to the same hemisphere except for 2 contralateral migrations through the thalamus. Most of the migrations were in close proximity (within the same lobe, to the adjacent lobe, from the basal ganglia to the cortex, from the cerebellum to the pons and interthalamus) except 1 from the basal ganglia to the cerebellum. A signal change along the presumed route of migration was seen in 3 patients.

Migration is a notable feature of cerebral sparganosis. Demonstration of migration on MR imaging could be a key diagnostic clue and beneficial for the treatment policy.