Objective: To evaluate the diagnostic accuracy of cranial ultrasound (CUS) for detection of neonatal arterial territory cerebral infarction in term infants. M ethods: CUS scans from term infants with neonatal magnetic resonance imaging (MR I) evidence of neonatal infarction were reviewed. The scans were grouped by acqu isition time after birth: 1-3 days (early) or 4-14 days (late). Results: Brain MRI showed infarction in the territory of the middle cerebral artery in 43 of 4 7 infants, anterior cerebral artery in one, and posterior cerebral artery in thr ee. Twelve of the 47 had minor changes on MRI in the white matter in the contral ateral hemisphere, and four infants had bilateral infarctions. The early CUS sca ns were abnormal in 68%of the infants; the late CUS scans were abnormal in 87% . The late CUS scans were correct for laterality and site of lesion in 25/47 (53 %) infants. In six infants with smaller lesions of the cortical middle cerebral artery branch or lesions in the posterior cerebral artery territory, the CUS sc ans were persistently normal. Conclusion: Normal early CUS scans do not exclude a diagnosis of neonatal stroke, although most scans are abnormal. CUS scans perf ormed after day 3 were abnormal in 87%of infants. CUS scan findings were accura te for lesion laterality and site in 53%, and, in 34%, the scans showed abnorm ality strongly suggestive of infarction but not always site specific. For optima l prognostic information, infants with clinical histories or CUS scan findings s uggestive of infarction should have a neonatal brain MRI scan. Objective: To evaluate the diagnostic accuracy of cranial ultrasound (CUS) for detection of neonatal arterial territory cerebral infarction in term infants. M ethods: CUS scans from term infants with neonatal magnetic resonance imaging (MR I) evidence of neonatal infarction were reviewed. scans were grouped by acquisition time after birth: 1-3 days (early) or 4-14 days (late). Results: Brain MRI showed infarction in the territory of the middle cerebral artery in 43 of 4 7 infants, anterior cerebral artery in one, and posterior cerebral artery in thr ee. Twelve of the 47 minor minor changes on MRI in the white matter in the contral ateral hemisphere, and four infants had bilateral infarctions. The early CUS sca ns were abnormal in 68% of the infants ; the late CUS scans were abnormal in 87%. The late CUS scans were correct for laterality and site of lesion in 25/47 (53%) infants. In six infants with smaller lesions of the cortical middle cerebral artery branch or lesions in the poste The CUS scans perf ormed after day 3 were abnormal in 87% of infants. CUS scan findings were accused for lesion laterality and site in 53%, and, in 34%, the scans showed abnorm ality strongly suggestive of infarction but not always site specific. For optima l prognostic information, infants with clinical histories or CUS scan findings s uggestive of infarction should have a neonatal brain MRI scan.