Magnetic resonance (MR) imaging has been suggested to be helpful in delineating the lesions during the acute phase of angiostrongyliasis caused by Angiostrongylus cantonensis. In this study, antibody titers in serum samples of 3 rabbits were determined by enzyme-linked immunosorbent assay, and brain MR images were obtained from 6 rabbits. The antibody titer elevated rapidly in the first 4 wk postinfection (PI) before reaching a plateau. However, suspicious changes in brain MR images near the left lateral ventricle and hippocampus were found only in 1 rabbit on day 28 PI. These findings indicate that immunologic responses in the central nervous system at the early stage of angiostrongyliasis are not sufficient to be observed by image studies.