Fig. 1

Imaging findings of syntelencephly, craniosynostosis, and sinus pericranii in the present case. a T2-weighted head MRI at age 2 years and 4 months. Abnormal midline connection between the cerebral hemispheres of the posterior frontal lobes and cingulate gyrus are shown (black arrow). The basal ganglia and thalamus are separated bilaterally (black arrow head). b Head computed tomography findings at age 4 months. The cranial sutures were not fused (white arrows). Tortuous and dilated subcutaneous veins were observed in the parietal region (white arrow heads). c Head computed tomography findings at age 2 years and 5 months. Two parietal skull bone defects (white arrows) and coronal craniosynostosis are visible. Digital impression on the skull was not evident. d T1-weighted head MRI at age 2 years and 4 months. Sinus pericranii (white arrow) via the parietal bone defect can be seen. The white arrowheads indicate distension of the subcutaneous veins in the parietal region. Callosal hypoplasia and ectopic gray matter around the lateral cerebral ventricles can also be observed. The black arrow indicates the tight posterior fossa and slight descent of the caudal part of the cerebellum toward the foramen magnum. Agenesis of the body of the corpus callosum and continuity of the cingulate gyrus across the midline are also shown. e Color cranial Doppler ultrasound findings at age 2 years and 5 months. Blood flow in two abnormal blood vessels (sinus pericranii) through the parietal bone defects to the extracranial veins can be seen (white arrow). The subcutaneous veins show distension (white arrow heads). f Cerebral angiography confirmed that the abnormal blood vessels formed a communication between the superior sagittal sinus and parietal diploic and subcutaneous veins (white arrows). No obvious thrombi, dural sinus abnormalities, or other vascular malformations were observed. The subcutaneous veins show distension (white arrow heads). L → R, left–right view (upper); A → P, anterior–posterior view (lower)