Hemodynamic Studies of Intracranial Dural Arteriovenous Fistulas Using Arterial Spin-Labeling MR Imaging

Abstract

<jats:p> Arterial spin-labeling (ASL) magnetic resonance imaging (MRI) enables non-invasive acquisition of the brain perfusion information in cerebrovascular disease. We investigated hemodynamic changes in intracranial dural arteriovenous fistulas (DAVFs) using ASL-MRI. </jats:p><jats:p> ASL-MRI by a Q2TIPS sequence on a 3.0-Tesla MRI was performed for three patients with Cognard's IIa+b type of DAVFs before and after treatment. Perfusion images obtained by ASL-MRI (ASL images) before treatment were visually compared with those by single-photon emission computed tomography images (SPECT images). Increasing rates of temporal changes of regional perfusion values in ASL images (ASL values) before and after treatment were also calculated. </jats:p><jats:p> In all three patients, ASL images before treatment demonstrated high perfusion in regions around the shunting areas, where normal or low perfusion were detected on SPECT images; thus, ASL images might have demonstrated the abundant arterial shunting flow via the fistulas. On days eight to 20 after treatment, ASL values around the shunt areas remained the same or decreased, and those in the regions other than the shunt areas increased in all three patients. This might have been due to a combination of the following: a decrease in shunt flow volume, an amelioration of venous congestion, and a sustained an upward shift in the autoregulation of the brain perfusion pressure. All regional ASL values decreased on days 112 and 120 after treatment in two patients, which possibly reflects a reduction in the upward shift in autoregulation. </jats:p><jats:p> ASL-MRI might be useful for identifying the hemodynamic behavior of DAVFs before and after treatment. </jats:p>

Arterial spin-labeling MR imaging of cerebral hemorrhages

“…Other masking ROI maps of the bilateral cerebellar hemispheres, frontal lobes, lentiform nuclei, limbic lobes, occipital lobes, parietal lobes, temporal lobes, and thalami as suggested by the WFU Pickatlas (WFU PickAtlas, Joseph Maldjian, MD, Wake Forest University School of Medicine, North Carolina, USA, http://www.fmri.wfubmc.edu/ download.htm) were also created and used for calculation of CBF-ASL values in other areas (Appendix 1). The details regarding these processing methods are as described [14][15][16].…”

Arterial spin labeling MR imaging aids to identify cortical venous drainage of dural arteriovenous fistulas

“…ASL-PWI can depict arteriovenous shunting as a high venous ASL-PWI signal intensity due to direct blood flow between feeding arteries and draining veins without intervening capillary bed. [ 10 – 12 ] Visualization of CVD on ASL-PWI images as hyperintensity in cortical veins has been reported in several previous studies. [ 10 , 11 ] Noguchi et al have reported that all 6 patients with DAVF Borden type III and 1 of 4 patients with Borden type II have marked hyperintense areas in cortical veins.…”

“…[ 9 ] In addition, ASL-PWI is useful for depicting draining veins as hyperintense venous signal in patients with DAVF. [ 10 – 12 ] Recently, ASL-PWI has been incorporated as part of the cerebrovascular disease evaluation in our institution. With its increasing use, we have encountered DAVF patients with CVD showing characteristic bright signal in cortical veins or affected brain parenchyma on ASL-PWI images.…”

Arterial Spin-labeling in Central Nervous System Infection

“…ASL-MRI can visualize arterial blood flow feeding both intra- and extra-axial regions, as long as the flow passes through the labeling area that is placed in the cervical region. 6 High perfusion on ASL-MRI might visualize hyperemia in the meningeal lesions or represent the epileptic activities as mentioned above. Although FLAIR is highly sensitive for meningitis, 19 meningeal hyperintensity on FLAIR is not uncommon in other differential diseases involving the leptomeninges, 20 such as subarachnoid hemorrhage 21 and meningeal carcinomatosis.…”

“…Because of its noninvasive nature, ASL-MRI can be used to safely obtain cerebral blood flow images even in children and pregnant women. ASL-MRI has demonstrated the clinical efficacy in cases of brain tumor, 3 dementia, 4 stroke, 5 dural arteriovenous fistula, 6 moyamoya disease, 7 , 8 and so on. Although characteristic findings of brain perfusion imaging have been reported for CNS infection, most of the studies employed nuclear-medicine- or contrast-enhanced-MRI-based perfusion imagings, while only a few reports employed ASL-MRI.…”