Atlantoaxial rotatory subluxation/fixation
Heather Borders, MD
over 3 years ago
Please choose a workflow. A standard workflow allows you to browse the repository with full case detail; the academic workflow allows you to browse the repository with limited case detail revealed. Double click on the images to launch image viewer.
Joseph Junewick, MD FACR
|Diagnostic Category: Vascular
|Created: over 5 years ago
|Updated: over 5 years ago
Term infant with prenatal history of hydrocephalus.
Subsequent diagnosis of thrombophila.
US – Spectral Doppler demonstrates low resistive index (increased diastolic flow).
MR – Multifocal cerebral cortical restricted diffusion. Colpocehalic posterior lateral ventricles.
Ischemic perinatal stroke is related to arterial or venous thrombosis. Often these injuries are multifocal. Initially, involved regions are associated with edema with distortion of the gray-white matter junction and obliteration of the sulci.
Doppler assessment of the intracranial arteries can reveal perfusion disturbance and predict hypoxic-ischemic injury before there are gray-scale changes. A normal Doppler of the anterior or middle cerebral arteries in a term infant should demonstrate uniform systolic and diastolic velocities and a resistive index between 0.6 and 0.8. Low resistive index (increased diastolic velocity) reflects cerebral hyperemia from vasodilation after hypoxic-ischemic event. Non-uniform systolic and/or diastolic velocities may indicate loss of autoregulation.
MR is helpful for the confirmation of ischemia. During the first week there will be increased signal on diffusion imaging with corresponding decreased signal on the apparent diffusion coefficient map. After the first week, progressively decreased T1 and increased T2 signal will become manifest. Post-gadolinium hyperintensity may be seen between 1 and 2 weeks.
1. Heinz ER, Provenzale JM. Imaging Findings in Neonatal Hypoxia: A Practical Review. AJR 2009; 192:41-47.
2. Chao CP, Zaleski CG, Patton AC. Neonatal Hypoxic-Ischemic Encephalopathy: Multimodality Imaging Findings. Radiographics 2006; 26:S159-S172.
3. Stark JE, Siebert JJ. Cerebral Artery Doppler Ultrasonography for Prediction of Outcome after Perinatal Ischemia. J Ultrasound Med 1994; 13:595-600.