Susceptibility-Weighted Imaging: A New Tool in the Diagnosis and Evaluation of Abnormalities of the Vein of Galen in Children

Abstract

SUMMARY:We retrospectively identified 9 consecutive children, 3 males and 6 females (age 5.2 Ϯ 6.3 years, range 1 day to 18 years), with known or suspected AVGs who underwent MR imaging, including SWI, at our institution between January 2007 and March 2011. On the SWI sequence, arterialized blood flow was considered to be present in the vein of Galen or its tributaries when these showed abnormal signal hyperintensity from arteriovenous shunting. SWI findings were correlated with findings from DSA studies or findings from time-of-flight or contrast-enhanced MR angiography sequences. SWI was found to accurately differentiate between high-flow and low-flow AVGs and was also useful in characterizing the arterial supply and venous drainage patterns associated with high-flow AVGs.ABBREVIATIONS: AVG ϭabnormality of the vein of Galen; AVS ϭ arteriovenous shunting; VGAD ϭ vein of Galen aneurysmal dilation; VGAM ϭ vein of Galen aneurysmal malformation S WI is an MR imaging technique that combines both phase and magnitude signal to produce high-resolution images of the cerebral venous system. 1 In SWI, veins appear hypointense due to the presence of deoxyhemoglobin and the arteries are hyperintense due to time-of-flight effects and lack of T2* effects. 1,2It has recently been shown that this property of SWI could be used to accurately detect AVS in cerebral vascular malformations by identifying the presence of abnormal hyperintense signal within the veins draining these malformations; this high signal is a result of AVS and arterialized blood flow in these veins.3 SWI studies are of high resolution and do not require intravenous contrast administration, features that can make these studies particularly useful in evaluating the presence of AVS in cerebral vascular malformations occurring in small children. We therefore retrospectively reviewed the utility of SWI in a series of patients with abnormalities of the vein of Galen. When there is AVS associated with such abnormalities, it could be from arteriovenous shunting into a persistent median vein of the prosencephalon (vein of Markowski), otherwise called a VGAM, or from a pial arteriovenous malformation that drains into the vein of Galen, resulting in a VGAD. In this context, we studied if the SWI technique could accurately differentiate between VGAMs and VGADs. When either of these high-flow abnormalities with AVS were identified by the SWI studies, we assessed the ability of these studies to provide information on the angioarchitecture associated with these abnormalities as well as their hemodynamic consequences. Case Series Patient SelectionThe study was approved by our hospital's institutional review board and conducted in compliance with the Health Insurance Portability and Accountability Act. On a retrospective review of a prospectively maintained data base, we found that between January 1, 2007, and February 28, 2010, 9 children (6 females and 3 males, mean age 5.2 Ϯ 6.3 years) underwent MR imaging with SWI at our institution for evaluation of known or suspected AV...

Anatomy of the deep venous system in vein of Galen malformation and its changes after endovascular treatment depicted by magnetic resonance venography

“…When dealing with children and especially critically ill newborns, better imaging modalities of the veins without the use of contrast material would be highly preferable and crucial. In this context, further research on SWI and VGM, as recently published by Jagadeesan et al14 is needed.…”

Intracranial Arteriovenous Shunting: Detection with Arterial Spin-Labeling and Susceptibility-Weighted Imaging Combined

“…Our results were in agreement with previous studies showing that SWI and ASL are 2 effective techniques to detect intracranial AVS. [8][9][10][11][12][13][14][15] Jagadeesan et al 10 demonstrated that SWI was 93% sensitive and 98% specific for the detection of AVS in patients with AVM. SWI was also found to accurately differentiate between high-flow and low-flow abnormalities of the vein of Galen in children.…”

Non-enhanced MR imaging for preinterventional assessment of the angioarchitecture in vein of Galen malformations

“…Angioarchitecture was characterized using MRI based on the work of Geibprasert et al 5 and Jagadeesan et al 6. Choroidal type VGMs have small plexiform arteriovenous choroidal shunts that can have a nidus-like appearance on MR images (see illustrative case No 1, figure 2).…”