Rihei Takeda

Quantification of regional cerebral blood flow and vascular reserve in childhood Moyamoya disease using [123I]IMP-ARG method

Both regional cerebral blood flow (rCBF) and regional vascular reserve (rVR) in ten childhood Moyamoya disease were quantified pre- and post-operatively by autoradiographic processing using single photon emission computed tomography (SPECT) and N-isopropyl-rho-iodoamphetamine (IMP) (IMP-ARG method) to estimate hemodynamic effectiveness of surgical revascularization. Before surgery, in two patients, rCBF was reduced in the whole territories and loss of rVR in the anterior circulation was observed; +4.3% in the anterior cerebral artery (ACA), -3.0% in the middle cerebral artery (MCA) and +17.5% in posterior cerebral artery (PCA) territories. After surgery, in eight patients without transient ischemic attack (TIA) episodes, rCBF at rest was maintained around subnormal level in the whole territories, and mean rVR was up to +11.9, +17.3 and +28.3% in ACA, MCA and PCA territories, respectively. However, rVR in the anterior circulation was significantly reduced in comparison with rVR in the posterior circulation. Quantification of both resting rCBF and rVR using IMP-ARG method could provide reliable information concerning on surgical indication and its effectiveness in childhood Moyamoya disease.

Treatment Results of Poor-grade (WFNS Grade V) Patients with Subarachnoid Hemorrhage

Although surgical treatment of poor-grade patients with ruptured cerebral aneurysms is still challenging, it is well known that some patients become independent after surgical intervention. Controversy is how to select patients with factors predictive of favorable outcome. The purpose of this paper is to extract factors predictive of favorable or poor outcome from analysis of our treatment results.

Local fibrinolysis for MCA and basilar artery embolism.

Purpose: We reviewed our clinical results of local fibrinolysis for Middle cerebral artery embolism (MCAE) and Basilar artery embolism (BAE) to discuss the propriety of our criteria for the indication of this treatment by comparing the results with conservative medical therapy.Materials and Methods: Since 1990.10 to 1999.11 we have had 75 cases of local fibrinolysis (MCAE 52 cases, BAE 19 cases and others 4 cases). Our criteria for the indication are 1) Cerebral embolism without any ischemic change at the initial CT, MRI and MRI-DWI. 2) Cerebral embolism within 6 hours from the onset (MCAE). 3) Preserving the residual CBF of ischemic territories over than 15 ml /100 g/min in 133 Xe-SPECT (MCAE). 4) No time limitation in BAE. Endovascular technique using microcatheter was applied for local fibrinolysis and rtPA (5-15 M units) or Urokinase (0.24-0.96 M units) were injected at the position of embolus or beyond the embolus.Results: Angiographical results were (MCAE/BAE) full reopening 17/12, partial reopening 23/4, embolus migration 4/1 and no change 7/2. Three months follow-up outcome evaluated by Glasgow Outcome Scale were (MCAE/BAE) good recovery 34/11, moderate disability 10/0, severe disability 4/1, persistent vegetative state 0/2 and death 4/5. In comparison with the conservative medical therapy group, local fibrinolysis is superior in GR and SD rate, and large infarction rate in MCAE and in GR rate in BAE.Conclusions: Local fibrinolysis with evaluation of residual CBF in MCAE could achieve angiographical and clinical improvements. And it is superior to the conservative medical therapy group in some points.

Correlation of SPECT with Angiography in Early Ischemic Stroke

The hyperacute thrombolytic therapy for selected patients with embolic stroke may actually provide benefit rather than risk [1–9]. The patient selection in thrombolytic stroke therapy might depend on early diagnosis of severity of cerebral ischemia or reversibility in ischemic brain tissue. It has been known that not only the time from the onset of stroke but also the residual cerebral blood flow (CBF) appear to be crucial for survival of marginal hypoperfusion areas [10–12]. A critical level of residual CBF might indicate functional reversibility in ischemic brain tissues and could be restored by early efficient recanalization of the occluded vessels. Cerebral angiographic studies in the early phase of embolic stroke could show prompt development of collateral circulating, reflecting residual CBF, and the degree of reperfusion following thrombolytic therapy in relation to increased CBF. To investigate the role of cerebral angiography in acute embolic stroke, we studied the correlation of CBF using single photon emission computed tomography (SPECT) with angiographic findings in early ischemic stroke within 6 h from the stroke onset.

Effect of Urokinase Cisternal Irrigation on Decrease of Subarachnoid Clot and Cerebral Vasodilatory Capacity during Cerebral Vasospasm

Within 24~48 hours after start of urokinase cisternal irrigation, an extreme amount of hemoglobin derived from the subarachnoid clot was withdrawn. CT number of cerebral cisterns decreased immediately in cases of urokinase cisternal irrigation while the reduction of CT number was slower in cases with cisternal drainage. Cerebral vasodilatory capacity assessed by DIAMOX(R) activated 123IIMP SPECT during the first and second week after subarachnoid hemorrhage showed less limitation in cases with urokinase cisternal irrigation than with cisternal drainage. Angiographical and symptomatic vasospasm were also expressed less severely in cases of urokinase cisternal irrigation than with cisternal drainage, and subsequently, no low density area in CT due to ischemia from vasospasm appeared with urokinase cisternal irrigation. In conclusion, urokinase cisternal irrigation accelerated clearance of subarachnoid clots, followed by reduction of severity of vasospasm and cerebral ischemia.

Monitoring of somatosensory evoked potentials during extracranial revascularization

Intraoperative somatosensory evoked potentials (SEPs) were measured in 17 patients during 21 extracranial revascularization and related procedures. The operations included 13 carotid endarterectomies (CEAs), two cervical internal carotid ligations, one vertebral artery (VA) clipping, one VA-common carotid artery (CCA) transposition, and four temporary balloon occlusion tests (TBOTs). Three of the 13 CEAs (23%) showed reduced amplitude and delayed latency of primary cortical SEPs during clamping of the carotid artery, followed by their recovery after emplacement of the internal shunt. Flattening of SEPs during clamping of the CCA was observed in the case of VA-CCA transposition; however, SEPs returned to normal immediately after insertion of a balloon indwelling shunt into the CCA. One of the four TBOTs showed alteration of SEPs during balloon occlusion of the subclavian artery proximal to the origin of the VA. In the others, SEPs remained stable during the entire procedure. Only one transient intraoperative ischemic complication was encountered among the cases of CEA. It was detected through flattening of SEPs, which led to the discovery of an internal shunt obstruction. Carotid stump pressure was also measured in 12 CEAs and two TBOTs, and seven of these 14 had pressure less than or equal to 50 mmHg. Four of the seven had carotid stump pressure less than or equal to 30 mmHg, and three of these four also showed altered SEPs. SEPs remained stable if the collateral flow was sufficient during vascular occlusion and showed obvious alteration when the blood flow was reduced to below the threshold. The authors conclude that monitoring of SEPs during extracranial revascularization is very useful.