Natural history of solitary cerebral cysticercosis on serial magnetic resonance imaging and the effect of albendazole therapy on its evolution.

AIM: To describe the evolution of imaging characteristics of solitary cerebral cysticercal lesions (SCCL) on serial MRI, and to study the effect of treatment with albendazole.

DESIGN: Randomised controlled prospective trial.

METHODS AND MATERIAL: 123 patients with new-onset seizures and SCCL on contrast MRI were randomised to treatment with albendazole and followed with up to five serial MRIs.

RESULTS: 81 patients (M - 41, F - 40) with mean age of 19.6+/-11.7years and 4 or 5 serial MRI were included in the analysis. Analysis was performed on 356 MRI's. Scolex was seen in 61.9% of patients in postcontrast T1 sequence in the first MRI study, and there was a significant drop in visibility from the next scan onwards. Cyst contents were initially T1-hypointense and T2-hyperintense with inversion on FLAIR in 30.8% and later scans showed T2-hypointensity. Cyst wall characteristics changed significantly from initially T2-hypointensity to later hyperintense rim. Initial scan revealed perilesional oedema in 98.5%, which is resolved by the second scan. Around 17.5% showed subtle perilesional T2-hyperintensity in follow-up scans. Enhancement pattern changed significantly from ring to disc, and later to non-enhancement. Initially, 69.7% lesions were in colloid-vesicular stage. Lesions moved through subsequent stages of cyst degeneration: time needed for this process is described. Imaging characteristics, both on the first and on subsequent scans, did not differ between albendazole and control groups.

CONCLUSIONS: Evolution of SCCL follows a predictable sequence corresponding to morphologic stages described earlier, taking over a year to complete. Contrast enhancement decreases as degeneration progresses, but some calcific lesions continue to enhance. Albendazole therapy may hasten resolution of inflammation around the lesion but affects neither the morphology of the cysticercus nor the process of degeneration and subsequent healing.