Usefulness of intraoperative laser Doppler flowmetry and thermography to predict a risk of postoperative hyperperfusion after superficial temporal artery–middle cerebral artery bypass for moyamoya disease

We investigated whether postoperative hyperperfusion in moyamoya disease can be predicted using intraoperative laser Doppler flowmetry and/or thermography. A prospective study was conducted on 27 patients (39 hemispheres) with moyamoya disease who underwent superficial temporal artery–middle cerebral artery (STA–MCA) bypass. During surgery, regional cerebral blood flow (rCBF) was measured with a laser Doppler flowmeter and the temperature of the cortical surface was measured with an infrared thermograph. Postoperative hyperperfusion was assessed immediately after surgery based on CBF study under sedation (propofol) as >100% increase in corrected rCBF compared to preoperative values. Postoperative hyperperfusion on CBF was observed in two patients (7.4%). A significant correlation was observed between intraoperative rCBF changes and postoperative rCBF increase (Pearson’s method: r = 0.555, p = 0.0003; simple regression: Y = 1.22X + 3.289, r ² = 0.308, p = 0.0004). Furthermore, the rCBF changes measured by laser Doppler flowmetry were significantly greater in patients with postoperative hyperperfusion (p = 0.0193) and CHS (p = 0.0193). The present study suggests that intraoperative rCBF measurement using laser Doppler flowmetry may predict a risk of post-EC–IC bypass cerebral hyperperfusion in moyamoya disease.     

Intraoperative brain surface blood flow monitoring using IRIS V thermographic imaging system in patients with Moyamoya disease

Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving CBF. But little is known about the changes of intraoperative cerebral hemodynamics and its effect on postoperative neurological status including symptomatic cerebral hyperperfusion. To address this issue, we applied a novel infrared camera system (IRIS-V thermographic system) for real-time, visual monitoring of surface CBF during surgery in patients with moyamoya disease. Seven patients (8 sides, male:female= 3:4, 7-62 years old) with moyamoya disease were included in the study. After STA-MCA anastomosis, STA were occluded transiently and recanalized, and whole sequence was recorded by IRIS-V system. Correlation between clinical, radiological findings and infrared imaging were investigated. Patency of bypass was confirmed by this camera during surgery in all cases. The intraoperative imaging patterns were divided into two groups. Group A: Change of brain surface color (++) (3 cases). Group B: Change of brain surface color (-) (4 cases). Transient symptomatic hyperperfusion occurred in all patients in Group A, whereas all patients in Group B showed non-symptomatic transient focal hyperperfusion on SPECT. No patient suffered permanent neurological deterioration compared to preoperative status. Characteristic pattern of the intraoperative cerebral hemodynamics as delineated by IRIS-V could be the optimal predictor for postoperative transient symptomatic hyperperfusion after direct bypass in patients with moyamoya disease.     

Diagnostic value of perfusion-weighted MRI for evaluating postoperative alteration of cerebral hemodynamics following STA-MCA anastomosis in patients with moyamoya disease

OBJECTIVE: Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). But little is known about the changes of CBF and its effect on neurological status during the acute stage after direct bypass for moyamoya disease. METHODS AND RESULTS: Perfusion-weighted magnetic resonance imaging (PWI) by the SE-EPI method was performed 4 and 10 days after superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis on 11 sides of 9 patients (male:female = 2:7, 24-61 years old) with moyamoya disease. All patients underwent single-photon emission computed tomography (SPECT) 1 and 7 days after surgery. The time-to-peak (TTP) by PWI showed focal decrease at the site of the anastomosis 4 days after STA-MCA anastomosis compared to preoperative TTP, and was further decreased in larger territory 10 days after surgery in all patients. Postoperative cerebral blood volume (CBV) by PWI showed significant increase compared to preoperative CBV in four patients who suffered symptomatic cerebral hyperperfusion after surgery. Postoperative SPECT revealed apparent increase of CBF in all patients and the patency of the STA-MCA bypass was confirmed by MRA. All patients were discharged without neurological deterioration compared to preoperative neurological status, and none of them suffered ischemic attack after surgery. CONCLUSION: Postoperative decrease in TTP by PWI could be a sensitive parameter for the normalization of CBF after STA-MCA anastomosis in patients with moyamoya disease. Postoperative increase in CBV may suggest cerebral hyperperfusion and could be the optimal predictor for hyperperfusion syndrome after STA-MCA anastomosis in patients with moyamoya disease.     

Seizure following superficial temporal-middle cerebral artery anastomosis in patients with moyamoya disease: possible contribution of postoperative cerebral hyperperfusion

Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). Seizure is known as a rare complication after revascularization for moyamoya disease, although its underlying mechanism is undetermined. We investigated the relationship between seizure attack and postoperative alteration in CBF in patients with moyamoya disease. CBF was routinely measured by N-isopropyl-p-[123I] iodpamphetamine (123I-IMP-SPECT) 1 and 7 days after superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis on 64 sides of the 44 consecutive patients (male:female = 13:31, 2-62 years old) with moyamoya disease. Three patients (male:female = 1:2, 40-55 years old) suffered from seizure attack at 1 to 10 days after surgery. Two of the three patients manifested as seizures at 8-10 days after surgery and presented transient neurologic deteriolation before seizure. Postoperative SPECT revealed significant increase in CBF at the sites of the anastomosis in all three patients. Postoperative magnetic resonance imaging showed no ischemic changes, and magnetic resonance angiography showed the apparently patent STA-MCA anastomosis as thick high signal intensity sign in all three patients. The anatomical location and the temporal profile of hyperperfusion were completely in accordance with the focus of seizure attack. Intensive blood pressure control and the use of antiepileptic agents were instituted. The neurologic deficits were resolved and no seizure attack recurred in three patients. Seizure following STA-MCA anastomosis can be caused by hyperperfusion in patients with moyamoya disease. When seizure attacks occur, routine CBF measurement is recommended to differentiate hyperperfusion and ischemia, since the treatments for these conditions are contradictory.     

Significance of Cerebral Blood Flow Analysis in the Acute Stage after Revascularization Surgery for Moyamoya Disease

Moyamoya disease is a chronic, occlusive cerebrovascular disease with unknown etiology characterized by steno-occlusive changes at the terminal portion of the internal carotid artery, either bilaterally or unilaterally, and an abnormal vascular network at the base of the brain. Surgical revascularization such as extracranial-intracranial (EC-IC) bypass is the preferred procedure for moyamoya disease. Despite the favorable long-term outcome, cerebral infarction and hyperperfusion syndrome are potential complications of this procedure, which can lead to neurological deterioration in the acute stage. In light of the similar clinical presentations between perioperative ischemia and hyperperfusion, it is essential to attempt a prompt cerebral blood flow (CBF) measurement in the acute stage after EC-IC bypass for moyamoya disease to differentiate these distinct pathologies, because the management of cerebral ischemia and hyperperfusion is contradictory to each other. Routine CBF analysis by single-photon emission computed tomography and/or magnetic resonance imaging not only facilitated a safer perioperative management but also provided important information about dynamic pathology of the hemodynamic conversion in the acute stage after revascularization surgery for moyamoya disease. We represent the current status of CBF analysis during the perioperative period of revascularization surgery for moyamoya disease, and sought to discuss its significance and efficacy to avoid surgical complications.     

Temporary neurologic deterioration due to cerebral hyperperfusion after superficial temporal artery-middle cerebral artery anastomosis in patients with adult-onset moyamoya disease

BACKGROUND: Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving CBF, but little is known about the change in CBF and its effect on neurologic status during the acute stage after revascularization. METHODS: 123I-IMP-SPECT was performed 1 and 7 days after STA-MCA anastomosis on 34 sides of 27 consecutive patients with adult-onset moyamoya disease (6 men, 21 women; 22-62 years old). The follow-up period ranged from 5 to 28 months (mean, 17.6 months). RESULTS: Thirteen patients (13 sides, 38.2%) suffered temporary neurologic deterioration due to hyperperfusion several days after surgery, which was sustained for several days (7.4 days in average). Postoperative magnetic resonance imaging/angiography showed the STA as a higher intensity signal than the preoperative finding without ischemic changes in all 13 patients. Postoperative SPECT revealed focal intense increase in CBF at the sites of anastomosis in all 13 patients. Eleven patients (32.4%) had transient focal neurologic deficit mimicking ischemic attack. Two patients (5.9%) had cerebral hyperperfusion syndrome associated with subarachnoid hemorrhage extending to the ipsilateral sylvian cistern. Symptoms were relieved by intensive blood pressure control, and no patients had permanent neurologic deficit or delayed neurologic deterioration during the follow-up period. CONCLUSIONS: Surgical revascularization including STA-MCA anastomosis is a safe and effective treatment for moyamoya disease, although temporary neurologic deterioration due to hyperperfusion could occur at a substantial rate. Routine CBF measurement is recommended for accurate diagnosis of postoperative hyperperfusion in moyamoya disease because its treatment is contradictory to that for ischemia.     

Magnetic resonance imaging in patients with cerebral hyperperfusion and cognitive impairment after carotid endarterectomy

OBJECT: Cerebral hyperperfusion after carotid endarterectomy (CEA) impairs cognitive function and is often detected on cerebral blood flow (CBF) imaging. The purpose of the present study is to investigate structural brain damage seen on magnetic resonance (MR) images obtained in patients with cerebral hyperperfusion and cognitive impairment after CEA. METHODS: One hundred and fifty-eight patients with ipsilateral internal carotid artery stenosis (> or = 70%) underwent CEA. Neuropsychological testing was performed preoperatively and at the 1st postoperative month. Cerebral blood flow was measured using single-photon emission computed tomography before, immediately after, and 3 days after surgery. Magnetic resonance imaging was performed before and 1 day after surgery. In patients with post-CEA hyperperfusion (defined as a CBF increase > or = 100% compared with preoperative values) on CBF imaging, MR images were also obtained on the 3rd postoperative day, the day on which hyperperfusion syndrome developed, and 1 month after the operation. RESULTS: The incidence of postoperative cognitive impairment was significantly higher in patients with post-CEA hyperperfusion on CBF imaging (12 [75%] of 16 patients) than in those without (6 [4%] of 142 patients; p < 0.0001). Only 1 of 5 patients with cerebral hyperperfusion syndrome developed reversible brain edema in the cerebral hemisphere ipsilateral to the CEA on MR images obtained on the day hyperperfusion syndrome occurred. However, postoperative cognitive impairment developed in all 5 patients with cerebral hyperperfusion syndrome regardless of the presence or absence of new lesions on MR images. In addition, postoperative cognitive impairment developed in 5 (45%) of 11 patients with asymptomatic cerebral hyperperfusion on CBF imaging despite the absence of new lesions on any postoperative MR images. CONCLUSIONS: Although cerebral hyperperfusion syndrome after CEA sometimes results in reversible brain edema visible on MR imaging, postoperative cerebral hyperperfusion -- even when asymptomatic -- often results in impaired cognitive function without structural brain damage on MR imaging.     

Transient crossed cerebellar diaschisis due to cerebral hyperperfusion following surgical revascularization for moyamoya disease: case report

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.     

Selection of patients for extra-intracranial arterial bypass surgery based on rCBF measurements.

Extracranial intracranial arterial anastomosis is gaining acceptance as a form of treatment in selected cases with ischemic cerebrovascular disease. To establish indications for this operation and to provide an objective assessment of postoperative results, regional cerebral blood flow (rCBF) studies were performed in 110 patients with cerebrovascular insufficiency considered for extra-intracranial bypass surgery. The 133Xe intracarotid injection method with 16 externally placed detectors was used for measuring rCBF. Postoperatively, rCBF was measured in 40 patients. From these results our present criteria for surgery have evolved. The probability of a good postoperative result is best in patients who showed focal cerebral ischemia or a moderate general reduction of CBF with an additional ischemic focus. The operation is contraindicated in patients with either normal or severely reduced CBF values (less than 60% of normal).     

Asymptomatic intracerebral hemorrhage under strict blood pressure control due to postoperative cerebral hyperperfusion in a patient with moyamoya disease

We report a case of moyamoya disease manifesting as asymptomatic intracerebral hemorrhage due to postoperative cerebral hyperperfusion, despite the prophylactic intensive blood pressure control. This 35-year-old man initially suffered from right upper quadrantanopsia and was found to have cerebral infarction in the left occipital lobe due to moyamoya disease. He also manifested preoperatively a small intracerebral hemorrhage at the left caudate nucleus. The left cerebral hemisphere showed apparent hemodynamic compromise, thus he underwent left superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis with indirect pial synangiosis. He was subjected to prophylactic strict blood pressure control postoperatively to avoid hyperperfusion syndrome. The N-isopropyl-p-¹²³I-Iodoamphetamine SPECT (¹²³I-IMP-SPECT) 1 day after surgery showed intense increase in cerebral blood flow (CBF) at the site of the anastomosis, and further blood pressure lowering was attempted. He did not suffer from neurologic deterioration during the postoperative period, while computed tomography (CT) 7 days after surgery revealed asymptomatic intracerebral hematoma (ICH) at the subcortex under the site of the anastomosis. Cerebral hyperperfusion is a potential complication of revascularization surgery for moyamoya disease. Accurate diagnosis and proper management of hyperperfusion are essential to avoid deleterious neurologic event due to hyperperfusion.     

Cerebral blood flow in moyamoya disease

Summary A study has been made of the cerebral blood flow (CBF) in moyamoya disease from the perspective of hemispheric cerebral blood flow and regional CBF (rCBF). The material includes 21 children between the ages of 5 and 15 years with moyamoya disease, and 19 adult moyamoya cases-all of which had virtually no neurological symptoms at the time of the study. CBF was measured using the¹³³Xe intravenous injection method. Comparsion was made with the measurements from 16 normal children and 14 normal adults. Study was also made of the relationship between the angiographic stage of the disease and the CBF.With the exception of the more elderly patients, CBF was found to be significantly lower in the moyamoya cases than in normal subjects of the same age group. In all age groups, the distribution of rCBF showed a dominant posterior distribution, dissimilar to the dominant anterior distribution found in the normals. Among the juvenile moyamoya cases, there was a tendency toward decreasing hemispheric blood flow together with advancing disease-as determined angiographically. Moreover, with advancing stages of the disease, there was a continuing transition from the normal pattern of frontal dominance to one of occipital dominance. This dominance of posterior rCBF is thought to be a characteristic feature of moyamoya disease.     

Clinical manifestations of infantile moyamoya disease

PURPOSE: The present study aimed to clarify clinical manifestations of infantile moyamoya disease by comparing them with those of schoolchild moyamoya disease. SUBJECTS AND METHODS: This study included a total of 55 patients who were diagnosed as moyamoya disease on cerebral angiography. Their medical records were precisely evaluated. CT or MRI was performed to examine the location of cerebral infarction in all subjects. Cerebral blood flow was measured in 33 patients before surgery, using the 133-xenon inhalation method and single photon emission computed tomography (SPECT). Postoperative full-scale IQ (FSIQ) was also examined. RESULTS: Of 55 patients, onset age was < 6 yr in 32 (infantile group) and > or = 6 yr in 23 (schoolchild group). Completed stroke was significantly more frequent in the infantile group than in schoolchild group (p = 0.0014). Incidence of cerebral infarct was also higher in the infantile group than in the schoolchild group (p = 0.0023). PCA stenosis/occlusion was observed in 14 of 32 infantile patients, but only in 4 of 23 schoolchild patients (p = 0.0474). Mean cerebral blood flow value was significantly lower than control value in the infantile group, but not in the schoolchild group. The effect of bypass surgery on cerebral ischemic attack was satisfactory in both groups. However, the postoperative FSIQ value was significantly lower in the infantile group than in the schoolchild group (p = 0.0452). CONCLUSIONS: The present study showed that infantile moyamoya disease involves a higher risk for cerebral infarct and completed stroke due to its more advanced stage, and that earlier diagnosis and treatment should be performed to improve the mental prognosis of patients.     

Intraoperative assessment of cortical perfusion by indocyanine green videoangiography in surgical revascularization for moyamoya disease

Background

Postoperative hyperperfusion is a potential complication of the direct bypass procedure for moyamoya disease (MMD). However, no reliable modality is available yet for the prediction of postoperative hyperperfusion during surgery for MMD. This study aimed to investigate whether semiquantitative analysis of indocyanine green (ICG) videoangiography could contribute to the prediction of postoperative hyperperfusion in MMD.

Methods

This study included 12 hemispheres from 10 patients who underwent surgical revascularization for MMD. Intraoperative ICG videoangiography was performed before and after a direct bypass procedure. The ICG intensity-time curves were semiquantitatively analyzed to evaluate cortical perfusion by calculating the blood flow index (BFI). Using single-photon emission computed tomography (SPECT), postoperative cerebral blood flow measurements were performed thrice: immediately, and 2 and 7 days after surgery.

Results

BFI significantly increased from 21.3?±?10.5 to 38.4?±?20.0 after bypass procedures in all the hemispheres (p?p?Conclusions Our results suggest that semiquantitative analysis of BFI by intraoperative ICG videoangiography is useful in evaluating changes in cortical perfusion after bypass procedures for MMD and can predict the occurrence of early-onset hyperperfusion in MMD patients after direct bypass.     

Venous Reddening as a Possible Sign of Hyperperfusion after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis for Moyamoya Disease: Case Report

Here we report a case of moyamoya disease in which cortical veins reddened after superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis, following postoperative hyperperfusion. A 37-year-old man with moyamoya disease suffered cerebral infarction in his right hemisphere. Single photon emission computed tomography (SPECT) showed impaired cerebral blood flow (CBF) in both cerebral hemispheres. The patient underwent STA-MCA anastomosis in the right cerebral hemisphere. During operation, soon after declamping the STA, cortical veins near the anastomosis site changed its color from blue to red. This change was repeatable by clamping and declamping of the STA. Postoperative SPECT and computed tomography (CT) demonstrated increased CBF and subarachnoid hemorrhage at the anastomosis site, suggesting the occurrence of postoperative hyperperfusion. By strictly controlling the patient''s blood pressure, the syndrome resolved 1 week after the operation. We propose that the venous reddening after STA-MCA anastomosis may be a sign of postoperative hyperperfusion.     

Hemodynamic evaluation of vascular reconstructive surgery for childhood moyamoya disease using single photon emission computed tomography.

To evaluate the efficacy of vascular reconstructive surgery for childhood moyamoya disease, the cerebral blood flow (CBF) in 31 hemispheres of 16 patients was examined by single photon emission computed tomography (SPECT) using the 133Xe inhalation method. Results were divided into two groups; 17 hemispheres with superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis [A(+) group] and 14 hemispheres without anastomosis [A(-) group]. The mean hemispheric CBF (mCBF) and regional CBF (rCBF) in the frontal, temporal, occipital, and basal ganglia regions were calculated. Pre- and postoperative SPECT on the 10 hemispheres of the A(+) group showed an increase in mCBF in 6 hemispheres, the disappearance of the low perfusion area (LPA) in all 5 hemispheres where LPA was present before surgery, and an improvement in rCBF distribution (an increase in rCBF in the frontal and temporal lobes and a decrease in the basal ganglia). This suggests that vascular reconstruction is greatly effective in treating this disease. A comparison between the A(+) group and the A(-) group by postoperative SPECT, as well as the clinical outcomes and the postoperative findings of electroencephalography and angiography, revealed that the A(+) group was superior to the A(-) group in the frequency of LPA (12% and 43%, respectively) and rCBF in the frontal region where STA-MCA anastomosis was usually performed. These results indicate that STA-MCA anastomosis with indirect synangiosis is the most effective treatment of childhood moyamoya disease.     

Prediction and monitoring of cerebral hyperperfusion after carotid endarterectomy by using single-photon emission computerized tomography scanning

OBJECT: The purpose of this study was to determine whether the preoperative measurement of acetazolamide-induced changes in cerebral blood flow (CBF), which is performed using single-photon emission computerized tomography (SPECT) scanning, can be used to identify patients at risk for hyperperfusion following carotid endarterectomy (CEA). In addition, the authors investigated whether monitoring of CBF with SPECT scanning after CEA can be used to identify patients at risk for hyperperfusion syndrome. METHODS: Cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were measured before CEA in 51 patients with ipsilateral internal carotid artery stenosis (> or = 70% stenosis). Cerebral blood flow was also measured immediately after CEA and on the 3rd postoperative day. Hyperperfusion (an increase in CBF of > or = 100% compared with preoperative values) was observed immediately after CEA in eight of 12 patients with reduced preoperative CVR. Reduced preoperative CVR was the only significant independent predictor of post-CEA hyperperfusion. Forty-three patients in whom hyperperfusion was not detected immediately after CEA did not exhibit hyperperfusion on the 3rd postoperative day and did not experience hyperperfusion syndrome. In two of eight patients in whom hyperperfusion occurred immediately after CEA, CBF progressively increased and hyperperfusion syndrome developed, but intracerebral hemorrhage did not occur. In the remaining six of eight patients in whom hyperperfusion was detected immediately after CEA, the CBF progressively decreased and the hyperperfusion resolved by the 3rd postoperative day. CONCLUSIONS: Preoperative measurement of acetazolamide-induced changes in CBF, which is performed using SPECT scanning, can be used to identify patients at risk for hyperperfusion after CEA. In addition, post-CEA monitoring of CBF performed using SPECT scanning results in the timely and reliable identification of patients at risk for hyperperfusion syndrome.     

Temporal change of 3-T magnetic resonance imaging/angiography during symptomatic cerebral hyperperfusion following superficial temporal artery-middle cerebral artery anastomosis in a patient with adult-onset moyamoya disease

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is a safe and effective treatment for moyamoya disease, although recent evidence suggests its substantial risk for symptomatic cerebral hyperperfusion. The diagnostic value of single-photon emission computed tomography (SPECT) for postoperative hyperperfusion in moyamoya patients is well established, but that of magnetic resonance (MR) imaging/angiography is undetermined. A 22-year-old woman with hemorrhagic-onset moyamoya disease underwent STA-MCA anastomosis on the right hemisphere, but she suffered from transient left hemiparesis and facial paresis owing to cerebral hyperperfusion from 3 to 11 days after surgery as delineated by SPECT. The time-sequential 3-T MR angiography revealed intense high signal of donor STA and dilated branches of MCA around the site of the anastomosis. These findings were most prominent at 8 days after surgery, when her neurologic signs were most apparent. Intensive blood pressure control relieved her symptom and she was discharged without neurologic deficit. MR findings normalized 3 months later. The characteristic findings of 3-T MR angiography, which was not evident by 1.5-T MR angiography in the previous studies, may reflect intrinsic pathology of postoperative cerebral hyperperfusion. It could be a useful diagnostic tool after revascularization surgery for moyamoya disease.     

Temporal change of 3-T magnetic resonance imaging/angiography during symptomatic cerebral hyperperfusion following superficial temporal artery–middle cerebral artery anastomosis in a patient with adult-onset moyamoya disease

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is a safe and effective treatment for moyamoya disease, although recent evidence suggests its substantial risk for symptomatic cerebral hyperperfusion. The diagnostic value of single-photon emission computed tomography (SPECT) for postoperative hyperperfusion in moyamoya patients is well established, but that of magnetic resonance (MR) imaging/angiography is undetermined. A 22-year-old woman with hemorrhagic-onset moyamoya disease underwent STA-MCA anastomosis on the right hemisphere, but she suffered from transient left hemiparesis and facial paresis owing to cerebral hyperperfusion from 3 to 11 days after surgery as delineated by SPECT. The time-sequential 3-T MR angiography revealed intense high signal of donor STA and dilated branches of MCA around the site of the anastomosis. These findings were most prominent at 8 days after surgery, when her neurologic signs were most apparent. Intensive blood pressure control relieved her symptom and she was discharged without neurologic deficit. MR findings normalized 3 months later. The characteristic findings of 3-T MR angiography, which was not evident by 1.5-T MR angiography in the previous studies, may reflect intrinsic pathology of postoperative cerebral hyperperfusion. It could be a useful diagnostic tool after revascularization surgery for moyamoya disease.     

Intraoperative control of extracranial-intracranial bypass patency by near-infrared indocyanine green videoangiography

OBJECT: Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial-intracranial bypass patency. METHODS: Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moya-moya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA-posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter-equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography. In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA-MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG videoangiography could be positively validated during the postoperative course by performing DS or CT angiography. CONCLUSIONS: Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG videoangiography may help reduce the incidence of early bypass graft failure.     

Intra-operative hemorrhage due to hyperperfusion during direct revascularization surgery in an adult patient with moyamoya disease: a case report

Hemorrhagic complication is one of the notable surgical complications of the revascularization surgery for moyamoya disease (MMD). Cerebral hyperperfusion (CHP) has been considered as the underlying cause of this complication. It mostly occurs several days after surgery, but the intra-operative hemorrhage immediately after bypass has not been reported previously. A 21-year-old woman presented right thalamic hemorrhage and was diagnosed as having MMD by cerebral angiography. In light of the location of the hemorrhage at the vascular territory of posterior circulation and the manifestation of transient ischemic attack during the follow-up period, she underwent revascularization surgery to prevent future ischemic attack and rebleeding. Superficial temporal artery (STA) was uneventfully anastomosed to the temporal M4 branch of the middle cerebral artery in an end-to-side manner. A few minutes after the completion of the anastomosis, hemorrhage occurred in the fissure adjacent to the site of anastomosis. Indocyanine green (ICG) video angiography just before hemorrhage showed focal early filling through the STA graft with early venous filling around the site of the anastomosis. The bleeding was controlled by immediate hypotensive therapy (systolic blood pressure 117 to 91 mmHg). The mean blood flows of the STA graft measured by ultrasonic flowmetry before and after hypotensive therapy were 52.8 and 24.2 ml/min, respectively. Single-photon emission computed tomography (SPECT) on the next day after surgery showed focal hyperperfusion in the surgical side. Intra-operative ultrasonic flowmetry, ICG, and postoperative SPECT would explain that CHP was the potential cause of the hemorrhagic complication. This is the first case describing intra-operative hemorrhagic complication during revascularization surgery for MMD. Surgeons need to be aware of this rare complication and its management method.