Hemodynamic studies of intracranial dural arteriovenous fistulas using arterial spin-labeling MR imaging
1Department of Radiology, Faculty of Medicine, Saga University; Nabeshima, Saga, Japan. tnogucci@radiol.med.kyushu-u.ac.jp
Abstract:
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. 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. 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. ASL-MRI might be useful for identifying the hemodynamic behavior of DAVFs before and after treatment.
Insights
Arterial spin-labeling MRI revealed high perfusion in dural arteriovenous fistula shunts before treatment. Post-treatment, ASL-MRI showed decreased shunt flow and improved perfusion, aiding in understanding hemodynamic changes.
Area of Science:
- Neuroimaging
- Vascular Neurology
- Radiology
Background:
- Cerebrovascular diseases, such as intracranial dural arteriovenous fistulas (DAVFs), require accurate assessment of brain perfusion.
- Arterial spin-labeling (ASL) magnetic resonance imaging (MRI) offers a non-invasive method for evaluating brain blood flow.
- Understanding hemodynamic alterations in DAVFs is crucial for effective treatment and patient management.
Purpose of the Study:
- To investigate hemodynamic changes in intracranial dural arteriovenous fistulas (DAVFs) using ASL-MRI before and after treatment.
- To compare ASL-MRI findings with single-photon emission computed tomography (SPECT) in patients with DAVFs.
- To assess the utility of ASL-MRI in characterizing the temporal hemodynamic behavior of DAVFs.
Main Methods:
- ASL-MRI with a Q2TIPS sequence was performed on three patients with Cognard's IIa+b type DAVFs before and after treatment.
- Perfusion images from ASL-MRI were visually compared with SPECT images.
- Temporal changes in regional perfusion values were calculated from ASL images (ASL values) pre- and post-treatment.
Main Results:
- Pre-treatment ASL images showed high perfusion around shunt areas, contrasting with normal or low perfusion on SPECT images, indicating abundant arterial shunting.
- Post-treatment (8-20 days), ASL values near shunts stabilized or decreased, while other regions showed increased perfusion, suggesting reduced shunt flow, improved venous congestion, and altered autoregulation.
- Long-term follow-up (112-120 days) in two patients revealed decreased regional ASL values, possibly reflecting a normalization of cerebrovascular autoregulation.
Conclusions:
- ASL-MRI effectively visualizes high shunt flow in DAVFs, complementing SPECT imaging.
- ASL-MRI demonstrates dynamic hemodynamic changes following DAVF treatment, including reduced shunt flow and improved regional perfusion.
- ASL-MRI is a valuable tool for assessing the hemodynamic behavior and treatment response in patients with intracranial dural arteriovenous fistulas.
