Improving accuracy of cerebral blood flow measurements in laser speckle flowmetry.

Laser speckle flowmetry (LSF) can measure moving red blood cells in real time as changes in tissue blood flow; however, LSF values may not be sufficiently reproducible due to body movements and other factors. Therefore, it is difficult to compare absolute values of LSF directly. This study aimed to verify the influence of head fixation on improving the measurement accuracy and enabling the comparison of LSF values semi-quantitatively using an external standard. We first examined the effects of head fixation on LSF values obtained during cerebral blood flow (CBF) measurement through a bone window over the cerebrum in Sprague-Dawley rats. The LSF values in the bone window were semi-quantitated using the ratio of the external standard LSF values measured simultaneously in the same field of view in a unilateral common carotid artery ligation model to evaluate CBF. Head fixation halved the variability of LSF values when compared with measurements made without head fixation. The LSF laser focus position did not affect the LSF values provided the focus was positioned within the exposed cranium. Semi-quantitation of LSF values made it possible to monitor changes in CBF in each respective bone window over time in a model of unilateral carotid ligation. In conclusion, the stabilizing effect of head fixation on LSF values was clarified, and we observed that to improve measurement accuracy, the head should be immobilized. Semi-quantitation of LSF values was first introduced by using an external standard and appears to be useful in monitoring the CBF of each location separately.

[A Case of Pial Arteriovenous Fistulae Associated with Hereditary Hemorrhagic Telangiectasia].

Pial arteriovenous fistulae(pial AVF)are rare vascular lesions. Pial AVF is a complication of hereditary hemorrhagic telangiectasia(HHT)and is associated with a high mortality rate. Here, we report a case of a 14-year-old boy with pial AVF associated with HHT who presented with a seizure. CT and MRI showed enlarged vessels with venous varices in the Sylvian fissure. Digital subtraction angiography(DSA)revealed a pial AVF with a single feeder originating from the middle cerebral artery with large varicose venous drainage, which drained into the transverse sinus, and superior sagittal sinus. A transarterial coil embolization was performed. During the procedure, flow control by a balloon guiding catheter was used. The patient had no neurological deficits after treatment. However, while microsurgery or endovascular treatment are the primary treatment options for pial AVF, there is no consensus regarding their efficacy. Using a balloon guiding catheter to control flow is useful for the treatment of pial AVF with a high-flow shunt.

Rapid de novo Formation of a Large Aneurysm in a Patient with Fibromuscular Dysplasia.

Objective: The authors report the first case of intracranial fibromuscular dysplasia (FMD) presenting with rapid de novo formation of an unruptured large vertebral artery (VA) fusiform aneurysm. Case Presentation: A 41-year-old man presented with left hemiparesis. He had a giant thrombosed aneurysm at the basilar artery-superior cerebellar artery (BA-SCA) junction and a left extracranial VA aneurysm. A de novo VA fusiform aneurysm developed during a 1-month interval following the first session of intravascular coil embolization for the BA-SCA aneurysm. Stress on the fragile artery due to FMD during micro-catheterization may have caused the de novo aneurysm. An anomalous aortic origin of the left VA may also have played a role in the formation of the large de novo aneurysm and extracranial VA aneurysm. We performed overlapping stent-assisted coil embolization for the VA fusiform aneurysm using an Enterprise VRDs, and coil embolization for the BA-SCA thrombosed aneurysm using the stent-assisted technique with an Enterprise stent. Both aneurysms remained occluded for 7 years. Conclusion: We concluded micro-catheterization to be the cause of the large de novo aneurysm. This case emphasizes the importance of carefully performing intravascular interventional procedures for patients with FMD.