MR Imaging of Shaken Baby Syndrome Manifested as Chronic Subdural Hematoma A B C Fig. 3. Chronic SDH in a two-month-old female patient. A. T1-weighted image shows low (though higher than CSF)-signal SDH in both cerebral hemispheres and the posterior fossa. In addi- tion, a high signal area, suggesting subacute hemorrhage, can be seen in the occipital areas (arrows). B. T2-weighted image reveals high signal intensity SDHs in both frontoparietal and occipital areas (arrows). C. Contrast-enhanced T1-weighted image demonstrates diffuse linear dural enhancement. gency department on account of a seizure 16 hours earlier, and for three days she had had a fever. She was a term ba- by with no perinatal problems, and the findings of physical and laboratory examinations were unremarkable. Simple skull and chest radiographs indicated no abnormality. MRI performed on the day of admission showed SDH in both cerebral hemispheres and the posterior fossa. The hematoma showed a low signal on T1-weighted images and a high signal on T2-weighted images. A bilateral focal high signal was also noted on both T1- and T2-weighted images of occipital areas, suggesting rebleeding or hemor- rhage of a different stage, and in addition, diffuse dural thickening and enhancement were observed. Subdural catheter drainage was undertaken the following day, and chronic hematoma was evacuated. Fundoscopic examina- tion was not performed. A meticulous interview with a so- cial worker revealed that the child had been abused. DISCUSSION SBS was first described by Caffey in 1972 as whiplash baby syndrome, and acceleration-deceleration stress is known to be the cause of the injury (1). Approximately two-thirds of shaken babies suffer permanent brain dam- age or die (6). Violent shaking can produce significant damage, especially to the brain or head and neck; this in- cludes intracranial hemorrhage, retinal hemorrhage, and hemorrhage in the high cervical cord (4, 5). Because their Korean J Radiol 2(3), September 2001 neck muscles are not strong enough to support their rela- tively large head compared with adults, and because their brains are not completely myelinated, infants are very sus- ceptible to shaking (7). SDH is the most common manifestation of head injury in SBS, and since SDH, especially chronic SDH, is a very rare cause of accidental injury among infants (3, 8, 9), radiolo- gists should suggest the possibility of SBS and child abuse. In young babies, whose CSF space is larger than in adults, bridging veins can easily be torn during shaking (1). If re- peated shaking leads to injury, SDH can be chronic and he- morrhage may occurr during both the acute and chronic stages, as in our cases (9). The presence of SDH of different ages is indicative of injuries from repeated abuse (2). Differentiation between acute and chronic SDH on the sole basis of a T1 or T2 signal can be difficult, and-as in our cas- es-dural enhancement observed at contrast-enhanced MRI and probably due to a granulation tissue membrane can be a helpful finding for diagnosing chronic SDH (9). Other manifestations, such as subarachnoid hemorrhage, cerebral contusion and diffuse axonal injury can also occur in SBS, but only SDH was noted in our three cases. Except for sub- arachnoid hemorrhage, MRI is superior to CT in diagnos- ing these head injuries (9). Retinal hemorrhage is one of the characteristic signs of SBS and is known to result from an abrupt rise in intracra- nial pressure during shaking (7). Birth trauma can cause retinal hemorrhage, though this resolves quickly (10). 173