Middle Cerebral Artery Anastomosis Research Articles

General anesthetic management of Prader-Willi syndrome patient undergoing middle cerebral artery-superficial temporal artery anastomosis

We experienced a case of a 17-year-old patient with genetically proven Prader-Willi syndrome who had left middle cerebral artery-left superficial temporal artery anastomosis surgery under general anesthesia with a non-depolarizing muscle relaxant. Prader-Willi syndrome is a genetic disorder associated with hypotonia. Using general anesthesia with a non-depolarizing muscle relaxant in these patients is difficult due to hypotonia. We, therefore, monitored the status of muscle relaxation with a train of four (TOF, TOF-Watch®, Organon, Ireland) during general anesthesia. Unlike infants, adolescents can have the muscle relaxation monitor on their body surface. Because lengthy, complex microsurgery was required for this vascular surgery, we had to use a muscle relaxant. However, when using a muscle relaxant, predicting the extent of the effect and the recovery time are difficult. The TOF ratio was 0.85 in the preanesthetic state. Anesthetic induction was done using the total intravenous anesthesia of the target concentration infusion method. Propofol target concentration at 4 µg/ml was initially injected. Remifentanil was injected at 0.15 µg/kg/min. Five minutes after an atracurium 15 mg injection, the TOF watch count was still at 2. Therefore, an additional 15 mg of atracurium was injected for intubation. When the TOF watch count was over 4, during the operation, an additional 5 mg of atracurium was injected. For the entire surgery, 65 mg of atracurium was used. The operation lasted for 2 hours and 50 minutes. After the operation, when the TOF ratio was 0.85, glycopyrrolate 0.4 mg and pyridostigmine 15 mg were injected. The endotracheal tube was removed once the patient regained spontaneous respiration and was fully awake. After extubation, the patient was arousable using painful stimulation. In the post anesthetic care unit, the patient had no respiratory problem and his TOF ratio was 0.85. The patient was then transferred to the general ward. Prader-Willi syndrome is a genetic disorder classically characterized by hypotonia, hypomentia, and hypogonadism that is associated with obesity [1]. The cause of hypotonia, muscle weakness, and motor problems in Prader-Willi patients are not clear. The contributing factors may be the abnormal body composition found in Prader-Willi patients, an increase in fat mass and a decrease in muscle mass, and, possibly, some degree of neuromuscular abnormality [2]. It has been reported that the motor problems are still present in childhood and adulthood, which causes the decrease in physical activity in Prader-Willi patients [3]. Thus, the hypotonia makes the choice of muscle relaxant difficult. Anesthetic management using atracurium and rocuronium have been reported [4,5]. However, few reports are available on using the intraoperative monitoring of the neuromuscular blockade for Prader-Willi patients. In this case, though the patient had hypotonia, anesthesia was successfully used with a dose adjusted muscle relaxant using the TOF watch.

External Carotid Artery Stenting and Superficial Temporal Artery to Middle Cerebral Artery Anastomosis for Internal Carotid Artery Occlusion With External Carotid Artery Severe Stenosis

Superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis may have inadequate effects in patients with internal carotid artery (ICA) occlusion and severe stenosis of the ipsilateral external carotid artery (ECA), because poor blood flow in the STA leads to insufficient flow to the MCA. In these patients, dilation of the stenotic ECA is required to improve the blood flow in the STA before STA-MCA anastomosis. A 71-year-old man presented with left hemiparesis and dysarthria. Magnetic resonance imaging revealed an old watershed infarction in the right cerebral hemisphere. Right carotid angiography showed right ICA occlusion and severe ipsilateral ECA stenosis. Single photon emission computed tomography (SPECT) demonstrated severe hemodynamic insufficiency in the right MCA territory. Instead of endarterectomy of the ECA, angioplasty and stenting (CAS) for ECA was performed to ensure adequate blood flow in the STA, due to the history of myocardial infarction and bifurcation of the common carotid artery at a high level (C2 level). Then STA-MCA anastomosis was performed 1 month later. Postoperative SPECT demonstrated marked improvement of hemodynamic insufficiency in the right MCA territory. After treatment, the patient had no ischemic events. This case suggests external CAS together with STA-MCA anastomosis is a good therapeutic option for a patient with symptomatic ICA occlusion and severe stenosis of the ipsilateral ECA if external CEA is difficult to perform.

Transient Crossed Cerebellar Diaschisis Due to Cerebral Hyperperfusion Following Surgical Revascularization for Moyamoya Disease

Crossed cerebellar diaschisis (CCD) often occurs after ischemic or hemorrhagic stroke that damages the cortico-ponto-cerebellar pathway. However, CCD due to cerebral hyperperfusion following cerebrovascular reconstruction is rare. A 61-year-old woman presented with transient CCD due to cerebral hyperperfusion following bypass surgery for adult moyamoya disease. She developed transient weakness of the right extremities and was diagnosed with moyamoya disease. First, she underwent superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis with indirect synangiosis on the left. Postoperative course was uneventful. Subsequently, she underwent STA-MCA anastomosis with indirect synangiosis on the right. She complained of mild headache on the right, and single photon emission computed tomography (SPECT) performed on the 7th postoperative day demonstrated hyperperfusion in the right frontal and temporal lobes associated with hypoperfusion in the left cerebellum. Magnetic resonance (MR) imaging demonstrated no new lesions and MR angiography showed patent STA-MCA bypass. Subsequent SPECT showed disappearance of both hyperperfusion and CCD. This case strongly suggests that cerebral hyperperfusion after bypass surgery for moyamoya disease may cause transient CCD. Although the clinical significance is still obscure, this phenomenon indicates the cortico-ponto-cerebellar pathway is interrupted due to hyperperfusion, suggesting the development of hyperperfusion syndrome. Careful observation of cerebral hemodynamics after bypass surgery is warranted to avoid hyperperfusion-related complications.

Bypass Surgery for Moyamoya Disease

This review describes the basic concepts of surgical revascularization for moyamoya disease, including direct and indirect bypass surgery. Direct bypass surgery can improve cerebral hemodynamics and reduce further ischemic events immediately after surgery, but may be technically challenging in some pediatric patients. Indirect bypass surgery is simple and has widely been used. However, its beneficial effects can be achieved 3 to 4 months after surgery, and surgical design is quite important to determine the extent of surgical collateral pathways. Combined bypass procedure, especially superficial temporal artery (STA) to middle cerebral artery anastomosis and indirect bypass, encephalo-duro-myo-arterio-pericranial synangiosis, is a safe and effective option to improve the short- and long-term outcome in patients with moyamoya disease. Alternative techniques are also described for specific cases with profound cerebral ischemia in the anterior cerebral artery or posterior cerebral artery territory. Special techniques to safely complete bypass surgery and avoid perioperative complications are presented, including methods to prevent delayed wound healing, to avoid facial nerve palsy after surgery, and to preserve the STA and middle meningeal artery during skin incision and craniotomy. Finally, the importance of careful management of patients is emphasized to reduce the incidence of perioperative complications, including ischemic stroke and hyperperfusion syndrome.

The efficacy of superficial temporal artery–middle cerebral artery anastomosis in patients with moyamoya disease complaining of severe headache

Some patients with moyamoya disease complain of severe headache, which may be closely related to cerebral ischemia. The efficacy of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis in these patients was evaluated by clinicoradiological studies. Of 117 consecutive patients with ischemic moyamoya disease, 25 complained mainly of severe headache (headache group) and 92 had no significant headache (nonheadache group). Intensity of headache was evaluated pre- and postoperatively. Furthermore, regional cerebral blood flow (rCBF) and cerebrovascular reactivity (CVR) were assessed pre- and postoperatively. The headache group was significantly younger than the nonheadache group. In a group corrected for the age distribution, preoperative rCBF and CVR were similar in headache and nonheadache groups. After STA-MCA anastomosis, 16 patients with headache experienced complete relief from headache, 7 patients showed remarkable improvements and discontinued medications for headache, and the remaining 2 patients had some alleviation of headache but sometimes required medication. In the headache group, the postoperative rCBF was significantly greater than the preoperative value. The postoperative rCBF in this group was also significantly greater than the postoperative rCBF in the nonheadache group. These data suggest that severe headache is one of the main symptoms in young patients with moyamoya disease probably related to cerebral circulatory disturbances. An STA-MCA anastomosis is effective in relieving headache in patients with ischemic moyamoya disease manifesting severe headache, probably by improving perfusion pressure and cerebral circulation.

Higher Magnification Microsurgical Repair of Donor Artery Dissection in Superficial Temporal Artery to Middle Cerebral Artery Anastomosis -Technical Note-

Donor artery dissection is a known cause of technical failure in microvascular anastomosis. A method for detection and direct repair of donor artery dissection before superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis is described using a high magnification operating microscope (maximum 50.4× magnification). Before STA-MCA anastomosis, the stump of the STA is stained using methylrosaniline chloride (pyoctaninum blue) and is observed under higher magnifications. Microsurgical suturing of the arterial dissection is performed before the anastomosis procedure under the high magnification microscope. This method was used in two patients with symptomatic hemodynamic cerebrovascular occlusive disease. Postoperative angiography revealed good patency and no complications occurred. This method may be useful for detection and direct repair of arterial dissection in small vessel walls before STA-MCA anastomosis.

Ischemic Stroke Due to Dissection of the Middle Cerebral Artery Treated by Superficial Temporal Artery-Middle Cerebral Artery Anastomosis-Case Report-

A 62-year-old man presented with dissection of the right middle cerebral artery (MCA) manifesting as mild headache, right hemiparesis, and slurred speech. Magnetic resonance (MR) imaging and MR angiography revealed fresh infarction in the right basal ganglia, and severe stenosis and dilatation of the right MCA. Digital subtraction angiography approximately 24 hours after admission revealed a linear contrast defect indicating an intimal flap of the M(1) segment. The diagnosis was dissection of the MCA. His neurological deficits improved gradually. Although he was neurologically stable, diffusion-weighted MR imaging revealed enlarging infarct size over the right MCA territory, and the right M(1) segment had progressive stenosis. Superficial temporal artery (STA)-MCA anastomosis was performed on the 26th day. Follow-up angiography showed good patency of the STA-MCA anastomosis, repair of the dissection of the M(1) segment, and improvement of the flow in the MCA. The patient was discharged from our hospital with no neurological deficits. Although the dissection in this case was spontaneously repaired, STA-MCA anastomosis was useful to get through a critical time. If the stenosis shows further progression or the infarction size enlarges, STA-MCA anastomosis may be effective.

Surgical treatment and perioperative management of moyamoya disease associated with glycogen storage disease Type 1a

The authors report a case of concurrent moyamoya disease and glycogen storage disease Type 1a that was successfully managed with bypass surgery. This 7-year-old Japanese girl, diagnosed with glycogen storage disease Type 1a at the age of 2 years, presented with repeated transient ischemic attacks. Cerebral angiography revealed severe stenosis at the terminal portions of the bilateral internal carotid arteries, with typical moyamoya vessels. The patient underwent superficial temporal artery-middle cerebral artery anastomosis and encephalomyosynangiosis bilaterally, in 2 staged procedures at an interval of 4 months. Despite perioperative administration of glucose, hypoglycemia and metabolic acidosis occurred after both surgeries. The symptoms were milder after the second surgery, in which an increased dose of glucose was used. The patient tolerated the perioperative conditions well under intensified medical treatment, and no further ischemic symptoms occurred.

Incidence and Pathogenesis of Transient Cheiro-Oral Syndrome After Surgical Revascularization for Moyamoya Disease

There are no reports that denote transient cheiro-oral syndrome (COS) after surgical revascularization for moyamoya disease. To clarify the incidence and pathogenesis of transient COS after surgical revascularization for moyamoya disease. This study included 21 patients who underwent superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and indirect bypass because of Moyamoya disease. Their medical records were evaluated to identify clinical features of postoperative transient COS. The findings on MRI, magnetic resonance angiography, and single-photon emission computed tomography were also analyzed. Transient COS developed in 8 (22.9%) of 35 operated hemispheres, or in 6 (28.6%) of 21 patients between 3 and 20 days after surgery. Most of the COS were associated with mild weakness of the ipsilateral face and hand. Simultaneous radiological studies detected no findings of cerebral infarct or postoperative hyperperfusion. STA-MCA anastomosis was patent in all patients. However, their disease stage more frequently progressed owing to considerable blood flow via STA-MCA anastomosis, and basal moyamoya vessels disappeared or diminished in patients with transient COS rather than in those without. Transient COS after surgical revascularization for moyamoya disease is not rare. Bypass flow through STA-MCA anastomosis may stimulate a rapid progression of disease stage and diminish basal moyamoya vessels, causing transient COS within 3 weeks after surgery.

Perfusion CT scanning and CT angiography in the evaluation of extracranial-intracranial bypass grafts

Extracranial-intracranial (EC-IC) bypass surgery remains an important treatment alternative for patients with occlusive cerebrovascular disease. The aim of the present study was to use perfusion CT and CT angiography (CTA) to evaluate cerebral hemodynamics and bypass patency in patients with occlusive cerebrovascular disease before and after EC-IC bypass surgery. Ten patients underwent perfusion CT and CTA before and after bypass surgery. Preoperative and postoperative digital subtraction angiography served as the diagnostic gold standard. An artery bypass was established from the superficial temporal artery to a cortical branch of the middle cerebral artery. Perfusion CT scanning was performed at the level of the basal ganglia. Color-coded perfusion maps of cerebral blood volume, cerebral blood flow, and time to peak were calculated. Preoperative perfusion CT showed significant prolonged time to peak and reduced cerebral blood flow of the affected hemisphere. Postoperative neurological deterioration did not develop in any patient. Computed tomography angiography provided adequate evaluation of the anastomoses as well as the course and caliber of the bypass and confirmed bypass patency in all patients. Postoperative perfusion CT showed improved cerebral hemodynamics with a return to nearly normal perfusion parameters. Computed tomography angiography is a noninvasive and reliable tool for evaluating patients with EC-IC bypass. Perfusion CT allows monitoring of hemodynamic changes after bypass surgery. The combination of both modalities enables noninvasive anatomical and functional analysis of superficial temporal artery-middle cerebral artery anastomoses using a single CT protocol. Hemodynamic evaluation of patients with occlusive cerebrovascular disease before and after surgery may improve the prediction of outcome and may help identify patients in whom a bypass procedure can be performed.

Novel Bypass Surgery for Moyamoya Disease Using Pericranial Flap

We reviewed our 11-year experience with a novel bypass procedure, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-arterio-pericranio-synangiosis (EDMAPS), for moyamoya disease regarding cerebral hemodynamics and long-term outcome. This prospective study included 75 patients with moyamoya disease, including 28 children and 47 adults. We performed STA-MCA anastomosis and EDMAPS on 123 hemispheres of 75 patients. In addition to conventional STA-MCA anastomosis and indirect bypass for the MCA territory, the medial frontal lobe was revascularized using the frontal pericranial flap through medial frontal craniotomy. Surgical results were analyzed with magnetic resonance imaging, cerebral angiography, and single-photon emission computed tomography/positron emission tomography. Overall incidences of mortality and morbidity were 0% and 5.7%, respectively. The annual risk of cerebrovascular events during the follow-up periods was very low: 0% in pediatric patients and 0.4% in adults over approximately 67 months. Postoperative cerebral angiography showed that the pericranial flap functioned well as donor tissue for indirect bypass, especially in pediatric patients. Follow-up single-photon emission computed tomography/positron emission tomography studies revealed that cerebral blood flow and its reactivity to acetazolamide markedly improved in both the MCA and anterior cerebral artery territories. These findings strongly suggest that STA-MCA anastomosis and EDMAPS using a frontal pericranial flap is a safe and effective surgical procedure to further improve the long-term prognosis in moyamoya disease by improving cerebral hemodynamics in both the MCA and anterior cerebral artery territories.

Emergency extracranial-intracranial bypass surgery for acute ischemic stroke

The purpose of this study was to evaluate the safety and efficacy of urgent extracranial-intracranial (ECIC) bypass in the management of intracranial cerebrovascular disease and acute cerebral ischemic injury in carefully selected patients. The authors reviewed the medical records and neuroimaging studies in 13 consecutive patients who underwent urgent surgical cerebral revascularization to treat acute cerebral ischemia. None were thought to be appropriate candidates for endovascular therapy. The patients' ages ranged from 21 to 65 years (mean 41.2 years). The mean follow-up review was 3.5 years, and no patient was lost to follow-up. Preoperative angiographic evaluation identified critical narrowing of the supraclinoid internal carotid artery (ICA) in 8 patients, the M(1) segment of the middle cerebral artery (MCA) in 3, and the cervical/petrous ICA in 2. All patients had progressive, refractory symptoms associated with enlarging areas of infarction on diffusion weighted MR imaging, despite maximal medical therapy, which included anticoagulation and antiplatelet agents, blood pressure elevation, and fluid resuscitation. All patients underwent superficial temporal artery-MCA anastomosis on an urgent basis. In every case, the bypass prevented further stroke progression. In 2 cases, revascularization was followed by rapid, dramatic improvement of preoperative neurological deficits. In the authors' experience, emergency EC-IC bypass in patients with acute ischemic injury was both safe and effective. This population was characterized by relatively young patients with severely limited collateral circulation. In this series of 13 carefully selected patients, bypass was successful in arresting progression of stroke, and in some cases resulted in rapid neurological improvement.

Pure Vasogenic Edema Caused by Cerebral Hyperperfusion After Superficial Temporal Artery to Middle Cerebral Artery Anastomosis -Case Report-

A 63-year-old patient presented with cerebral hyperperfusion manifesting as transient aphasia and general tonic convulsions 3 and 4 days after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. Diffusion-weighted magnetic resonance (MR) imaging revealed a focal low-intensity area at the site of anastomosis in the left temporal lobe, with high apparent diffusion coefficient, together with focal intense increase in cerebral blood flow in the same region. This lesion was considered to be pure vasogenic edema caused by cerebral hyperperfusion. Additional treatment with intravenous drip infusion of free radical scavenger and reduction in blood pressure with nicardipine improved the patient's symptoms and brain edema. The brain edema gradually decreased on MR imaging and completely disappeared at 3 months after bypass surgery. Cerebral hyperperfusion is often encountered after recanalization of occlusive arteries, removal of arteriovenous malformations, and carotid endarterectomy, but may also occur after STA-MCA anastomosis.

Clinical implications of intraoperative infrared brain surface monitoring during superficial temporal artery–middle cerebral artery anastomosis in patients with moyamoya disease

Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). Symptomatic cerebral hyperperfusion is a potential complication of this procedure, but its treatment is contradictory to that for ischemia. Because intraoperative techniques to detect hyperperfusion are still lacking, the authors performed intraoperative infrared monitoring in moyamoya disease using a novel infrared imaging system. During superficial temporal artery-middle cerebral artery anastomosis in 25 patients (26 hemispheres) with moyamoya disease, the authors monitored the brain surface temperature intraoperatively with the IRIS-V infrared imaging system. The average gradation value change (indicating temperature change) was calculated using commercial software. Magnetic resonance imaging, MR angiography, and N-isopropyl-p-[(123)I]iodoamphetamine SPECT studies were performed routinely before and within 10 days after surgery. Patency of bypass, detailed local hemodynamics, and changes in cortical surface temperature around the anastomosis site were well recognized by the IRIS-V infrared imaging system in all cases. In the present study, 10 patients suffered transient neurological symptoms accompanied by an increase in CBF around the anastomosis site, recognized as symptomatic hyperperfusion. The increase in temperature was significantly higher in these patients. Intensive blood pressure control was undertaken, and free-radical scavengers were administered. No patient in the present study suffered a permanent neurological deficit. Although the present method does not directly monitor surface CBF, temperature rise around the anastomosis site during surgery might be an indicator of postoperative hyperperfusion. Prospective evaluation with a larger number of patients is necessary to validate this technique.

USEFULNESS OF AN ULTRASONIC SCALPEL TO HARVEST AND SKELETONIZE THE SUPERFICIAL TEMPORAL ARTERY FOR EXTRACRANIAL-INTRACRANIAL BYPASS SURGERY

A new method to harvest and skeletonize the superficial temporal artery (STA) using an ultrasonic scalpel is presented. The technique is simple and safe, and reduces bleeding. We also investigated histopathological changes in donor vessels and whether it is possible to shorten the time needed for STA harvesting using the ultrasonic scalpel. Between January 1, 2005, and December 31, 2007, 31 consecutive patients underwent STA and middle cerebral artery anastomosis surgery in our hospital. All patients underwent harvesting of both the frontal and parietal branches of the STA. STA harvesting using an ultrasonic scalpel was performed in 18 of the 31 patients. We compared the time needed for STA harvesting by dividing patients into 2 groups: a non-ultrasonic scalpel group and an ultrasonic scalpel group. We also examined the histopathological changes by application of ultrasonic waves on the STA in the 6 most recent patients. The mean time needed for STA harvesting was 84.2 +/- 14.1 minutes for the non-ultrasonic scalpel group and 55.1 +/- 15.2 minutes for the ultrasonic scalpel group. The ultrasonic scalpel group showed a significantly shorter harvesting time than the non-ultrasonic scalpel group (P < 0.01). No histopathological change was observed in any layers of the STA. Our data suggest that STA harvesting with the ultrasonic scalpel may be useful for STA-middle cerebral artery anastomosis surgery.

Intracerebral hemorrhage caused by rupture of a giant aneurysm complicating superficial temporal artery–middle cerebral artery anastomosis for moyamoya disease

Aneurysm formation at the anastomosis site after extracranial-intracranial (EC-IC) bypass surgery for major arterial occlusion or stenosis due to atherosclerosis has only been reported a few times previously. However, no case describing the formation of a giant aneurysm after EC-IC bypass surgery has been reported to date. Additionally, this complication associated with moyamoya disease is extremely rare, and only one case has been reported so far. We report a case of a 51-year-old woman having a rare complication of intracerebral hemorrhage due to rupture of a giant aneurysm that developed after superficial temporal artery-middle cerebral artery anastomosis for the treatment of moyamoya disease. To the best of our knowledge, this is the first reported case of a giant aneurysm, also the largest so far occurring after EC-IC bypass surgery and the second reported case of a rupture of an aneurysm formed after bypass surgery for moyamoya disease.

External Carotid Artery Angioplasty and Stenting Followed by Superficial Temporal Artery to Middle Cerebral Artery Anastomosis

A 31-year-old man presented with right hemiparesis, and magnetic resonance imaging revealed a small infarct at left basal ganglia. Digital subtraction angiography showed left cervical internal carotid artery (ICA) occlusion and severe stenosis of the ipsilateral external carotid artery (ECA) with collateral cerebral circulation fed by ECAs. Based on the results of a functional evaluation of cerebral blood flow, we performed preventive ECA angioplasty and stenting for advanced ECA stenosis to ensure sufficient blood flow to the superficial temporal artery. Eight weeks later, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was performed. His postoperative course was uneventful and no additional transient ischemic attacks have occurred. To our knowledge, this is the first report of preventive angioplasty and stenting for advanced narrowing of an ECA before STA-MCA anastomosis for ipsilateral ICA occlusion.

Efficacy of the revascularization surgery for adult-onset moyamoya disease with the progression of cerebrovascular lesions

Object In moyamoya disease, despite its progressive nature of the occlusive lesions in pediatric patients, the prevalence of the progression in adult patients is undetermined. Furthermore, the optimal timing of the revascularization surgery for progressive cases is controversial. To address these issues, we retrospectively investigate four cases with the adult-onset moyamoya disease manifesting as progression before revascularization surgery. Methods From March 2004 to May 2007, 49 patients with adult-onset moyamoya disease aged from 19 to 62 years old (mean 40.5) underwent superficial temporal artery–middle cerebral artery (STA–MCA) anastomosis on 63 hemispheres. All patients were strictly followed up by magnetic resonance (MR) imaging/angiography postoperatively. Twenty-seven hemispheres of 15 adult patients without surgery were also followed up at outpatient service during the same period. If the patients manifest as the progression of the steno-occlusive lesion on the hemisphere without surgery, they undergo revascularization surgery after the confirmation of hemodynamic compromise. Results During this period, 47 hemispheres including those of outpatient cases were conservatively followed up after initial diagnosis. Among them, six hemispheres (12.8%) of four patients had been proven to show apparent progression of steno-occlusive lesion and were subjected to revascularization surgery. Postoperative courses were uneventful in all four cases, and no patient suffered cerebrovascular event on the operated hemisphere after surgery. Conclusion Adult-onset moyamoya disease, either bilateral or unilateral, has a substantial risk for progression, and careful follow-up is necessary for asymptomatic hemisphere. Once the patient manifests as the progression of cerebrovascular occlusive lesions or ischemic symptoms, we recommend revascularization surgery after the confirmation of the hemodynamic compromise.

TRACING COLLATERAL CIRCULATION AFTER ISCHEMIA IN RAT CORTEX BY LASER SPECKLE IMAGING

The collateral circulation is crucial for the pathophysiology and outcome of acute cortical ischemia. Current understanding of collateral circulation still remains sparse, largely due to prior limitations of spatial or/and temporal resolution in methods to evaluate these diminutive redistributive routes of cerebral blood flow (CBF) especially in leptomeningeal anastomoses that connected cortical arteries. In the study, based on a mini-stroke model, laser speckle imaging with high spatiotemporal resolution was used to assess the dynamic evolution of the collateral circulation around a mini-ischemia in the rat cortex. We found that the blood flow and diameter in the intra-arterial anastomoses were enhanced immediately after the ligation of one branch of middle cerebral artery and recovered to baseline level as arterial recirculation was performed. Whereas the communicative flow-through of the posterior cerebral artery and the middle cerebral artery anastomoses was not significant enough to be determined. This is the evidence that intra-arterial anastomoses were the primary routes to restore blood flow into the ischemic territory during the acute phase of ischemia, and laser speckle imaging method was proven as a powerful tool to be potential for subserving further investigation of the collateral circulation.

Intraoperative infrared brain surface blood flow monitoring during superficial temporal artery–middle cerebral artery anastomosis in patients with childhood moyamoya disease

To monitor patency of the bypass and to accomplish comprehensive visualized evaluation of brain surface hemodynamics in childhood moyamoya patients, we performed intraoperative monitoring using novel infrared imaging system. Intraoperative monitoring of brain surface blood flow by IRIS V infrared imaging system has been conducted during superficial temporal artery-middle cerebral artery anastomosis on seven sides of five pediatric patients with moyamoya disease (man/woman = 2:3, 7-8 years old). The range of recipient artery was 0.7-0.8 mm (average 0.75 mm). Magnetic resonance imaging and magnetic resonance angiography were performed routinely before and after surgery. In all cases, patency of bypass, as well as detailed local hemodynamics and changes of brain surface temperature distribution could be evaluated. Intraoperative infrared system will be a feasible monitoring not only for noninvasive intraoperative evaluation of bypass patency but also for local hemodynamics even in patients with childhood moyamoya disease.