Unusual Manifestation of a Vein of Galen Malformation: Value of CT Angiography Shoko Konno, Yuji Numaguchi, David A. Shrier, Jiang Qian, and Robert A. Sinkin Summary: We describe a neonate with aneurysmal dilatation of the vein of Galen with arteriovenous fistulous sites located at the superior vermian vein. Helical CT angiography was useful for evaluating the anomalous vessels. Index terms: Aneurysm, computed tomography; Computed to- mography, three-dimensional; Vein of Galen The vein of Galen aneurysm was described by Jaeger et al in 1937 (1). Since then, many investigators have discussed the embryology, anatomy, clinical presentation, and treatment of this anomaly (2). We report a case of a vein of Galen aneurysm presenting as an unusual manifestation, with arteriovenous fistulous sites located at the superior vermian vein. The lesion was analyzed by means of helical com- puted tomographic (CT) angiography in addi- tion to conventional CT and conventional angiography. Case Report A 4310-g infant was born to a 34-year-old mother by cesarean section after a 40-week gestation. The preg- nancy was uncomplicated. Apgar scores were 1/3/5 at 1, 5, and 10 minutes. After initial stabilization, the infant was transferred to our institution on the day of birth. On admission, the head was macrocephalic and sug- gestive of hydrocephalus, which was confirmed by sono- graphic examination of the head. Skull percussion and auscultation revealed hyperresonance and cranial bruits. Neurologically, the infant was alert but with poor tone, generalized weakness, and bilaterally fisted hands. Car- diac sonography on the same day revealed a structurally normal heart with severe right ventricular enlargement, increased pulmonary artery pressure, patent foramen ovale, and patent ductus arteriosus. There was right-to-left shunting and a significant diastolic runoff with an aortic steal phenomenon toward the cervical arteries. Further examination indicated hepatomegaly and pleural effusion. This high-output cardiac failure, together with the hydro- cephalus and cranial bruits, was strongly suggestive of a cerebral arteriovenous malformation. On day 2, the patient underwent a head CT study. An unenhanced CT scan of the head showed hydrocephalus and a large structure of homogeneous high density in the midline. Helical scanning was performed after intravenous injection of a total of 9 mL of contrast material via the dorsal metacarpal vein, with a collimator size of 1 mm, a table pitch of 1:1, and total area coverage of 60 mm. Axial reconstructed images at 1-mm intervals showed strong, uniform enhancement of the aneurysmally dilated vein of Galen as well as a markedly dilated vascular structure, suggesting the superior vermian vein with numerous ab- normal vessels in the posterior fossa. The straight sinus was absent. The helical scanning data were transferred to a workstation to reconstruct CT angiograms with a sur- face-rendering technique and with a maximum intensity projection technique in various projections. CT angio- grams showed direct fistulous communication between bilateral superior cerebellar arteries and a markedly di- lated superior vermian vein, which emptied into the dilated vein of Galen (Fig 1A–D). The branches of the posterior cerebral arteries and the anterior inferior cerebellar arteries emptied into the dilated superior vermian vein with arte- rioarterial networks. All fistulas were at the various sites of the superior vermian vein and no arteries drained into the vein of Galen. Anterior or middle cerebral arteries did not contribute as feeders. On day 3, conventional angiography was performed for transarterial embolization. Selective catheter placement could not be achieved owing to severe tortuosity of the carotid and vertebral arteries. The aortogram with the tip of the catheter at the aortic arch showed arteriovenous fistu- las in the posterior fossa (Fig 1E and F). Detailed evalua- tion of arterial feeders and fistulous sites was difficult ow- ing to the lack of selective catheterization. Transtorcular embolizations of the arteriovenous fistu- las were performed in two sessions, on day 4 and day 7. Despite the treatments, the patient continued to have high- Received July 14, 1995; accepted after revision November 20. From the Departments of Diagnostic Radiology (S.K., Y.N., D.A.S.), Pathology (J.Q.), and Pediatrics, Division of Neonatology (R.A.S.), University of Rochester (NY) Medical Center. Address reprint requests to Shoko Konno, MD, Department of Radiology, St Marianna University School of Medicine, 2–16 –1 Sugao Miyamae-ku, Kawasaki 216, Japan. AJNR 17:1423–1426, Sep 1996 0195-6108/96/1708 –1423 q American Society of Neuroradiology 1423