Echoplanar diffusion-weighted imaging in neonates and infants with suspected hypoxic-ischemic injury: Correlation with patient outcome

OBJECTIVE. Our objective was to examine the effectiveness of echoplanar diffusion-weighted (DW) imaging in detecting CNS ischemia in neonates and infants and to determine how well the imaging findings using this technique correlate with short-term neurologic deficit. MATERIALS AND METHODS. Echoplanar DW images, turbo T2-weighted images, and fluid-attenuated inversion recovery (FLAIR) sequences were obtained in a clinically defined cohort of 26 consecutive neonates and infants with suspected hypoxic- ischemic injury. Echoplanar DW imaging was performed with the diffusion gradient in the slice-select direction: b value, 1200 sec/mm²; matrix, 128 x 128, interpolated to 256 x 256. Four scans (4 sec per scan) were obtained and averaged to optimize the signal-to-noise ratio. Most patients were not sedated (n = 19). Abnormalities seen on DW imaging were correlated with clinical findings at short-term follow-up and compared with findings on FLAIR and turbo T2-weighted images. RESULTS. Short-term clinical follow-up showed neurologic deficit in 10 (83%) of 12 patients with DW images with abnormal findings, and no neurologic sequelae in 12 (86%) of 14 patients with DW images with normal findings. Echoplanar DW images revealed a greater extent of and a larger number of abnormalities compared with FLAIR or turbo T2- weighted images in 11 (92%) of 12 patients with DW images with abnormal findings. CONCLUSION. Echoplanar DW imaging reveals abnormalities poorly depicted on turbo T2-weighted and FLAIR images in neonates and infants with clinically suspected hypoxic-ischemic injury. DW imaging may be able to identify which patients are likely to develop at least short-term neurologic deficits and may afford the best early evaluation of short-term neurologic prognosis in these patients.