Objective: Regional cerebral blood flow (CBF) increasing focally at sites of neural activity is called "hemodynamic response (HDR)". In cases with severe cerebral ischemia, HDR may be disturbed and cause disruption of normal neuro-vascular coupling. HDR was measured during a motor task using functional near infrared spectroscopy (fNIRS) in cases with severe cervical internal carotid artery (ICA) stenosis before and after carotid artery stenting (CAS). Ischemia and the influence of therapy for it on HDR was analyzed. Methods: Seventeen right-handed patients with severe cervical ICA stenosis admitted for CAS were examined. fNIRS during a motor task was performed and concentration changes in oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HbR), and total hemoglobin (tHb) were calculated in these patients in addition to routine evaluations. The same measurements were repeated after CAS and serial data were evaluated. In order to analyze the relevance of HDR to CBF status, Xenon-enhanced computed tomography (Xe-CT) was performed before and after CAS. Results: Some abnormalities in the HDR curve and its recovery after CAS were detected, including a delay in peak time of tHb concentration, of more than 10 seconds during the 20 second stimulation, in 9 cases. TTP0.7 (time to peak) value, defined as the time to reach seventy percent of maximum tHb concentration, was observed to be higher in patients with low CBF at rest before CAS. In the group with a high TTP0.7 value, CBF at rest before CAS was lower than 35mL/100g/min., significantly lower than the group without a high TTP0.7 value (P<0.01). Additionally, in the group with a high TTP0.7 value, CBF increase after CAS was significantly higher than the group with a lower TTP0.7 value (P<0.01). Conclusions: In some cases with severe ICA stenosis, cortical hemodynamics, and oxygen metabolism during functional activation are disturbed, and CAS can modulate these changes. This result is important in that intervention for cervical IC stenosis can not only reduce ischemic events, but also influence cortical hemodynamics during functional activity.
Objective: Transarterial embolization (TAE) using liquid embolic material is adopted in the treatment of dural arteriovenous fistulas (DAVFs) with direct cortical venous drainage or in patients in whom transvenous access is limited. Arresting flow by wedging a microcatheter tip into a main feeding vessel is important to achieve complete obliteration of DAVF with TAE. The Masamune catheter is a double lumen microcatheter with a silicone balloon at its distal end, characterized by the shortness of its catheter tip to the distal balloon end. Two cases of DAVF treated by TAE with the balloon flow arrest technique using a Masamune balloon microcatheter are reported. Case Report: Case 1, a 50-year-old man, was incidentally diagnosed with a tentorial DAVF with direct cortical venous drainage. An inflated Masamune balloon catheter was wedged in the occipital artery, and trans-arterial embolization was performed under a flow-arrested condition. As preparative embolization of the other minor feeding arteries had not been performed, complete obliteration of DAVF was not achieved by competing flow. Case 2, a 64-year-old man, was diagnosed with a left transverse-sigmoid DAVF on angiogram. The DAVF was completely obliterated with the balloon flow arrest technique using liquid embolic material. Conclusion: The Masamune catheter can easily achieve an artificial flow-arrest condition by inflation of its distal balloon to prevent fragmentation of liquid embolic material. In conjunction with preparative embolization of minor feeding vessels, curative embolization may be achieved from a main feeder using this catheter.