PMC2713852_01
Multiple round and linear signal-void structures, which form a wedge-shape defect, are present in the left temporal lobe, suggesting the presence of an AVM in a 36-year-old man.. A, B, C. T1-(A), T2-(B), and enhanced T1-weighted (C) axial MR images are shown (TR/TE = 600/14 for T1WI and enhanced T1WI; TR/TE/acquisition = 4500/120/2 for TSE T2WI). After the injection of contrast medium, enhancement was minimal.. D. Prior to embolization, a large AVM nidus fed from a branch of the left middle cerebral artery is apparent, and there is early drainage, mainly to the distal left sigmoid sinus, via a dilated vein. Note early visualization of the left internal jugular vein. During the capillary phase, decreased opacity of contrast medium in the rest of the cerebral parenchyma was also noted.. E. After embolization with 5-0 silk suture, the previously noted dilated vein has completely disappeared and contrast filling in the remaining part of the brain is almost normal. A small part of the AVM, seen inferomedially, remains, and the filling time and density of the superior sagittal sinus and left internal jugular vein have normalized.. F. TR-MRA acquired prior to embolization shows, as does DSA, early visualization of the AVM nidus and dilated draining vein, and delayed visualization of the weakly enhanced superior sagittal sinus. Additionally, as in DSA, the left internal jugular vein is visualized during the early arterial phase.. G. TR-MRA obtained immediately after embolization shows that visualization of the dilated draining vein and remaining part of the AVM nidus, seen inferomedially, is delayed. Early visualization and normal filling of the superior sagittal sinus is noted, suggesting the regulation of blood flow in the remaining part.
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T1- and T2-weighted images depicted a wedge-shaped lesion containing multiple, variable-sized, linear or round signal void structures in the left temporal lobe, while Gd-DTPA-enhanced T1-weighted images showed minimal enhancement (Figs. 1A-C). After embolization of the AVM nidus, visualization of the previously noted dilated vein was delayed, and contrast filling of the unaffected part of brain was almost normal, as was the appearance of the left internal jugular vein (Figs. 1D, E). Filling of the superior sagittal sinus and left internal jugular vein was normal, however, suggesting the regulation of blood flow to normal brain parenchyma but decreased blood flow to the AVM (Figs. 1F, G).