Subclinical epileptiform discharges in Alzheimer's disease are associated with increased hippocampal blood flow

BACKGROUND

In epilepsy, the ictal phase leads to cerebral hyperperfusion while hypoperfusion is present in the interictal phases. Patients with Alzheimer's disease (AD) have an increased prevalence of epileptiform discharges and a study using intracranial electrodes have shown that these are very frequent in the hippocampus. However, it is not known whether there is an association between hippocampal hyperexcitability and regional cerebral blood flow (rCBF). The objective of the study was to investigate the association between rCBF in hippocampus and epileptiform discharges as measured with ear-EEG in patients with Alzheimer's disease. Our hypothesis was that increased spike frequency may be associated with increased rCBF in hippocampus.

METHODS

A total of 24 patients with AD, and 15 HC were included in the analysis. Using linear regression, we investigated the association between rCBF as measured with arterial spin-labelling MRI (ASL-MRI) in the hippocampus and the number of spikes/sharp waves per 24 h as assessed by ear-EEG.

RESULTS

No significant difference in hippocampal rCBF was found between AD and HC (p-value = 0.367). A significant linear association between spike frequency and normalized rCBF in the hippocampus was found for patients with AD (estimate: 0.109, t-value = 4.03, p-value < 0.001). Changes in areas that typically show group differences (temporal-parietal cortex) were found in patients with AD, compared to HC.

CONCLUSIONS

Increased spike frequency was accompanied by a hemodynamic response of increased blood flow in the hippocampus in patients with AD. This phenomenon has also been shown in patients with epilepsy and supports the hypothesis of hyperexcitability in patients with AD. The lack of a significant difference in hippocampal rCBF may be due to an increased frequency of epileptiform discharges in patients with AD.

TRIAL REGISTRATION

The study is registered at clinicaltrials.gov (NCT04436341).

Implications of Post-recanalization Perfusion Deficit After Acute Ischemic Stroke: a Scoping Review of Clinical and Preclinical Imaging Studies

The goal of reperfusion therapy for acute ischemic stroke (AIS) is to restore cerebral blood flow through recanalization of the occluded vessel. Unfortunately, successful recanalization does not always result in favorable clinical outcome. Post-recanalization perfusion deficits (PRPDs), constituted by cerebral hypo- or hyperperfusion, may contribute to lagging patient recovery rates, but its clinical significance remains unclear. This scoping review provides an overview of clinical and preclinical findings on post-ischemic reperfusion, aiming to elucidate the pattern and consequences of PRPD from a translational perspective. The MEDLINE database was searched for quantitative clinical and preclinical studies of AIS reporting PRPD based on cerebral circulation parameters acquired by translational tomographic imaging methods. PRPD and stroke outcome were mapped on a charting table, creating an overview of PRPD after AIS. Twenty-two clinical and twenty-two preclinical studies were included. Post-recanalization hypoperfusion is rarely reported in clinical studies (4/22) but unequivocally associated with detrimental outcome. Post-recanalization hyperperfusion is more commonly reported (18/22 clinical studies) and may be associated with positive or negative outcome. PRPD has been replicated in animal studies, offering mechanistic insights into causes and consequences of PRPD and allowing delineation of possible courses of PRPD. Complex relationships exist between PRPD and stroke outcome. Diversity in methods and lack of standardized definitions in reperfusion studies complicate the characterization of reperfusion patterns. Recommendations are made to advance the understanding of PRPD mechanisms and to further disentangle the relation between PRPD and disease outcome.

Association of RNF213 polymorphism and cortical hyperintensity sign on fluid-attenuated inversion recovery images after revascularization surgery for moyamoya disease: possible involvement of intrinsic vascular vulnerability

A cortical hyperintensity on fluid-attenuated inversion recovery images (FLAIR cortical hyperintensity (FCH)) is an abnormal finding after revascularization surgery for moyamoya disease. This study aimed to investigate the pathophysiology of FCH through genetic analyses of RNF213 p.R4810K polymorphism and perioperative hemodynamic studies using single-photon emission computed tomography. We studied 96 hemispheres in 65 adults and 47 hemispheres in 27 children, who underwent combined direct and indirect revascularization. Early or late FCH was defined when it was observed on postoperative days 0-2 and 6-9, respectively. FCH scores (range: 0-6) were evaluated according to the extent of FCH in the operated hemisphere. FCHs were significantly more prevalent in adult patients than pediatric patients (early: 94% vs. 78%; late: 97% vs. 59%). In pediatric patients, FCH scores were significantly improved from the early to late phase regardless of the RNF213 genotype (mutant median [IQR]: 2 [1-5] vs. 1 [0-2]; wild-type median: 4 [0.5-6] vs. 0.5 [0-1.75]). In adults, FCH scores were significantly improved in patients with the wild-type RNF213 allele (median: 4 [2-5.25] vs. 2 [2, 3]); however, they showed no significant improvement in patients with the RNF213 mutation. FCH scores were significantly higher in patients with symptomatic cerebral hyperperfusion than those without it (early median: 5 [4, 5] vs. 4 [2-5]; late median: 4 [3-5] vs. 3 [2-4]). In conclusion, the RNF213 p.R4810K polymorphism was associated with prolonged FCH, and extensive FCH was associated with symptomatic cerebral hyperperfusion in adult patients with moyamoya disease.

Imaging of status epilepticus: Making the invisible visible. A prospective study on 206 patients

BACKGROUND

Peri-ictal MRI abnormalities (PMA) frequently affect the cerebral cortex, hippocampus, pulvinar of the thalamus, corpus callosum, and cerebellum. In this prospective study, we aimed to characterize the spectrum of PMA in a large cohort of patients with status epilepticus.

METHODS

We prospectively recruited 206 patients with SE and an acute MRI. The MRI protocol included diffusion weighted imaging (DWI), fluid-attenuated inversion recovery (FLAIR), arterial spin labeling (ASL), and T1-weighted imaging pre-and post-contrast application. Peri-ictal MRI abnormalities were stratified as either neocortical or non-neocortical. Amygdala, hippocampus, cerebellum, and corpus callosum were regarded as non-neocortical structures.

RESULTS

Peri-ictal MRI abnormalities were observed in 93/206 (45%) of patients in at least one MRI sequence. Diffusion restriction was observed in 56/206 (27%) of patients, which was mainly unilateral in 42/56 (75%) affecting neocortical structures in 25/56 (45%), non-neocortical structures in 20/56 (36%) and both areas in 11/56 (19%) of patients. Cortical DWI lesions were located mostly in frontal lobes 15/25 (60%); non-neocortical diffusion restriction affected either the pulvinar of the thalamus or hippocampus 29/31 (95%). Alterations in FLAIR were observed in 37/203 (18%) of patients. They were mainly unilateral 24/37 (65%); neocortical 18/37 (49%), non-neocortical 16/37 (43%), or affecting both neocortical and non-neocortical structures 3/37 (8%). In ASL, 51/140 (37%) of patients had ictal hyperperfusion. Hyperperfused areas were located mainly in the neocortex 45/51 (88%) and were unilateral 43/51 (84%). In 39/66 (59%) of patients, PMA were reversible in one week. In 27/66 (41%), the PMA persisted and a second follow-up MRI was performed three weeks later in 24/27 (89%) patients. In 19/24 (79%) PMA were resolved.

CONCLUSIONS

Almost half of the patients with SE had peri-ictal MRI abnormalities. The most prevalent PMA was ictal hyperperfusion followed by diffusion restriction and FLAIR abnormalities. Neocortex was most frequently affected especially the frontal lobes. The majority of PMAs were unilateral. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Cerebral blood flow quantification with multi-delay arterial spin labeling in ischemic stroke and the association with early neurological outcome

Restoring blood flow to brain tissue at risk of infarction is essential for tissue survival and clinical outcome. We used cerebral blood flow (CBF) quantified with multiple post-labeling delay (PLD) pseudocontinuous arterial spin labeling (ASL) MRI after ischemic stroke and assessed the association between CBF and early neurological outcome. We acquired ASL with 7 PLDs at 3.0 T in large vessel occlusion stroke patients at 24 h. We quantified CBF relative to the contralateral hemisphere (rCBF) and defined hyperperfusion as a ≥30% increase and hypoperfusion as a ≥40% decrease in rCBF. We included 44 patients (median age: 70 years, median NIHSS: 13, 40 treated with endovascular thrombectomy) of whom 37 were recanalized. Hyperperfusion in ischemic core occurred in recanalized but not in non-recanalized patients (65.8% vs 0%, p = 0.006). Hypoperfusion occurred only in the latter group (0% vs 85.7%, p < 0.001). In recanalized patients, hyperperfusion was also seen in salvaged penumbra (38.9%). Higher rCBF in ischemic core (aβ, -2.75 [95% CI: -4.11 to -1.40]) and salvaged penumbra (aβ, -5.62 [95% CI: -9.57 to -1.68]) was associated with lower NIHSS scores at 24 h. In conclusion, hyperperfusion frequently occurs in infarcted and salvaged brain tissue following successful recanalization and early neurological outcome is positively associated with the level of reperfusion.

Safety and Efficacy of Induced Hypertension and Hypervolemia in Preventing Neurologic Complications After Combined Direct and Indirect Bypass in Hemorrhagic-Onset Moyamoya Disease

BACKGROUND

Perioperative management of blood pressure in patients undergoing surgical revascularization for moyamoya disease (MMD) remains a controversial topic. We evaluated the safety and efficacy of induced hypertension and hypervolemia (IHH) in preventing neurologic complications during the perioperative period after direct surgical revascularization in a large hemorrhagic-onset moyamoya disease (HOMMD) cohort.

METHODS

We retrospectively reviewed a prospectively managed departmental database of all HOMMD patients treated between 1987 and 2019. The study included 122 direct surgical revascularization patients. Patients were separated into groups on the basis of the presence or absence of IHH therapy and evaluated for occurrence of 30-day risk of transient neurologic events (TNEs), ischemic, and hemorrhagic complications.

RESULTS

Two-hundred and three revascularization procedures were performed on 122 patients for HOMMD treatment. Nineteen TNEs (9.4% of procedures) were observed in 18 (14.8%) patients. Two patients (1.6% and 1.0% of procedures) suffered from ischemic complications and 1 (0.8% and 0.5% of procedures) from hemorrhagic complications. No differences between groups in the severity, duration of TNEs, or length of hospital stay were noted. No patient in the IHH therapy group experienced a recurring TNE or readmission after discharge; however, this was not statistically significant owing to the small sample size. There were no differences in the rates of ischemic or hemorrhagic complications between groups with or without IHH therapy (P = 0.46 and 0.54, respectively).

CONCLUSIONS

Induced hypertension and hypervolemia appear safe in HOMMD. There were no significant differences in complication or TNE rates between the groups with or without IHH therapy. While we believe it is important to employ IHH therapy in MMD patients who present with ischemic symptoms, these findings suggest that prophylactic IHH therapy may not be necessary in MMD patients presenting with hemorrhage.

Intraoperative Neurophysiology and Transcranial Doppler for Detection of Cerebral Ischemia and Hyperperfusion During Carotid Endarterectomy

OBJECTIVE

To evaluate and compare efficacy of intraoperative neurophysiological monitoring (IONM) and intraoperative transcranial Doppler (TCD) techniques for identification of hypoperfusion during carotid artery clamp and hyperperfusion after release of occlusion during carotid endarterectomy.

METHODS

This was a retrospective, consecutive case series of 152 patients undergoing carotid endarterectomy between June 2018 and March 2020. Somatosensory evoked potentials, motor evoked potentials, electroencephalogram, and TCD were obtained.

RESULTS

Three patient cohorts were observed after clamping the carotid artery: A, in 132 of 152 patients (87%), TCD blood flow velocity decreased by <50% and there were no changes in IONM; B, in 5 of 152 (3%) patients, TCD blood flow rate was reduced 50%-100% with no changes in IONM; C, in 15 patients (10%), blood flow velocity was reduced by 50%-100% and all IONM modalities met warning criteria. With increased blood pressure, IONM and blood flow velocities improved to less than warning criteria in 8 of 15 patients. In 6 of the 7 remaining patients, IONM modalities recovered to baseline immediately after clamps were removed from the carotid artery. The 1 patient with persistent motor evoked potential deterioration experienced postoperative proximal muscle weakness, which recovered 48 hours later. In 22 patients, TCD detected hyperperfusion at the moment of clamp release.

CONCLUSIONS

TCD blood flow velocity is correlated with motor evoked potential and somatosensory evoked potential amplitude changes after clamping. After declamping, TCD can detect hyperperfusion and help regulate blood pressure to prevent hyperperfusion.

Hyperperfusion and intracranial hemorrhage after burr hole surgery of chronic subdural hematoma

Background:

Chronic subdural hematomas (CSDHs) mainly occur in elderly people and usually develop after minor head injuries. CSDH can be cured by a relatively simple burr hole surgery. Rarely reported, hemorrhagic postsurgical complications include subarachnoid, intracerebral, intraventricular, and remote cerebellar hemorrhages. The causes of such uncommon complications are difficult to explain and remain poorly understood.

Case Description:

We report the case study of an 89-year-old man with CSDH who presented with the right hemiparesis. He underwent burr hole surgery with a closed-drainage system. A computed tomography (CT) scan conducted the following day demonstrated an acute intraventricular hemorrhage and hyperperfusion of the ipsilateral hemisphere.

Conclusion:

This is a rare case of an acute hematoma in the ventricle following drainage of a CSDH. The likely mechanism of this intraventricular hemorrhage could be that the drainage of the hematoma produced a movement of the ventricle and hemisphere accompanied by hyperperfusion.

Combined Perfusion and Permeability Imaging Reveals Different Pathophysiologic Tissue Responses After Successful Thrombectomy

Despite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on k_trans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median k_trans elevation (IQR) of 0.77 (0.41–1.4) min⁻¹ and was found in all 7 cases of hypoperfusion (100%), in 10 of 16 cases of hyperperfusion (63%), and in only three of 13 cases with unaffected perfusion (23%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56–0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10–0.82]) compared to hyperperfusion (PPV = 0.93 [0.68–1.0]) or unaffected perfusion (PPV = 1.0 [0.75–1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression.

Characteristic Pattern of the Cerebral Hemodynamic Changes in the Acute Stage After Combined Revascularization Surgery for Adult Moyamoya Disease: N-isopropyl-p-[123I] iodoamphetamine Single-Photon Emission Computed Tomography Study

OBJECTIVE

Surgical revascularization for moyamoya disease (MMD) prevents cerebral ischemic attack by improving cerebral blood flow (CBF) and could also reduce the risk of re-bleeding in hemorrhagic-onset patients. We sought to clarify the cerebral hemodynamic changes in the acute stage after revascularization surgery for adult MMD.

MATERIALS AND METHODS

The present study includes 54 consecutive adult patients with MMD (21-76 years old, 43.1 average), undergoing superficial temporal artery-middle cerebral artery anastomosis with indirect pial synangiosis on 65 affected hemispheres. We prospectively performed single-photon emission computed tomography (SPECT) at postoperative day (POD) 1 and 7 of 65 surgeries. Perioperative management was conducted with strict blood pressure control (100-130 mmHg) and minocycline hydrochloride administration.

RESULTS

The outcome of 65 surgeries was favorable except for one (1.5%), which manifested as delayed intracerebral hemorrhage due to local hyperperfusion. The postoperative SPECT revealed the characteristic CBF improvement pattern with transient local hyperperfusion (POD1) and subsequent distribution of CBF in wider vascular territory (POD7) on 37 hemispheres (56.9%, 37/65).

CONCLUSION

The revascularization surgery is a safe and effective treatment for adult MMD, while transient local hyperperfusion should be strictly managed by intensive perioperative care.

Visualizing prolonged hyperperfusion in post-stroke epilepsy using postictal subtraction SPECT

Diagnosis of post-stroke epilepsy is often challenging because of a low incidence of epileptiform abnormalities on electroencephalography (EEG). Hence, this study evaluated whether postictal subtraction single-photon emission computed tomography (SPECT) could visualize epileptic activity and act as a diagnostic modality in post-stroke epilepsy. Fifty post-stroke epilepsy patients, who had undergone Tc-99m-ECD SPECT twice (postictal and interictal), were enrolled. The postictal hyperperfusion area was identified by subtraction (postictal-interictal) SPECT and classified into two distribution types: superficial or deep-seated. Laterality and distribution of postictal hyperperfusion on subtraction SPECT were compared with stroke lesions, seizure symptoms, and epileptiform EEG findings. Forty-three of the 50 patients (86%) had hyperperfusion on subtraction SPECT and 26 (52%) had epileptiform EEG findings. Subtraction SPECT showed prolonged postictal hyperperfusion despite the relatively long interval between seizure end and postictal SPECT (median: 19.1 h, range: 2.2-112.5 h). The laterality of the hyperperfusion area had a high concordance rate with the laterality of stroke lesions (97.7%), seizure symptoms (91.9%), and epileptiform EEG findings (100%). Scalp EEG identified epileptiform activity more frequently in superficial type of SPECT, but less frequently in deep-seated type (both, P = 0.03). Postictal SPECT can be complementary to scalp EEG in endorsing the diagnosis and location of post-stroke epilepsy.

Arterial spin labeling hyperperfusion in seizures associated with non-ketotic hyperglycaemia: is it merely a post-ictal phenomenon?

A 53-year-old chronic uncontrolled diabetic patient presented with one episode of generalized seizures followed by drowsiness and post-ictal confusion. MR imaging at admission revealed left temporal subcortical T2/FLAIR hypointensities with overlying cortical T2/FLAIR hyperintensities and increased perfusion on arterial spin labeling (ASL). Follow-up imaging at 4- and 8-week interval revealed persistent ASL hyperperfusion with significant resolution of conventional MR imaging findings. Delayed persistent ASL hyperperfusion suggests that hyperglycemia-induced increased blood-brain barrier permeability rather than a mere post-ictal phenomenon in non-ketotic hyperglycemia (NKH) and may result in long-term cognitive disturbances.

Epstein-Barr Virus-Associated Encephalopathy Presenting with Nonconvulsive Status Epilepticus in an Immunosuppressive State

Epstein-Barr virus (EBV) infection is occasionally accompanied by central nervous system (CNS) complications, particularly in immunosuppressed patients. However, the symptoms and clinical features of EBV infection in the CNS are rather heterogeneous and remain unknown. We herein describe the first reported adult case manifesting nonconvulsive status epilepticus (NCSE), possibly associated with reactivation of EBV in an immunosuppressive state. A 63-year-old man with a history of acute myeloid leukemia and taking immunosuppressants was admitted due to progressively impaired consciousness without any focal neurological signs, including paralysis or convulsions. Arterial spin labeling magnetic resonance imaging (ASL-MRI) and brain perfusion single-photon emission computed tomography showed hyperperfusion in the right temporal region, despite no morphological abnormalities in other MRI sequences. White blood cell counts, EBV viral load, and virus-capsid antigen IgG in cerebrospinal fluid were elevated. We diagnosed him with EBV-associated encephalopathy presenting with NCSE. Administration of levetiracetam, an antiepileptic, improved the consciousness and the abnormal hyperperfusion. This case suggests a new concept of EBV-associated encephalopathy leading to epilepsy, particularly in immunosuppressed patients.

Measurement of Intraoperative Graft Flow Predicts Radiological Hyperperfusion during Bypass Surgery in Patients with Moyamoya Disease

Introduction

Moyamoya disease (MMD) is a rare cerebrovascular disease associated with cerebral infarction or hemorrhage. Hyperperfusion is the most significant complication of direct bypass surgery. Previous research has shown that an increase in cerebral blood flow (CBF) is strongly related to symptomatic hyperperfusion and highlighted the importance of postoperative assessment of CBF.

Objective

The principal aims of this study were to quantitatively analyze the relationship between intraoperative graft flow and increase in CBF and to evaluate the effectiveness of intraoperative graft flow measurement during bypass surgery for patients with MMD.

Methods

This study included 91 surgeries in 67 consecutive adult patients with MMD who underwent direct revascularization surgery at our institution between November 2013 and September 2018. Intraoperative graft flow of the branches and main trunk was measured in all patients, after anastomosis had been established. Postoperative CBF measurements were performed under sedation, immediately after surgery. Radiological hyperperfusion was defined as focal high uptake, as determined by CBF imaging immediately after surgery. Patients were divided into two groups (radiological hyperperfusion and nonradiological hyperperfusion groups), and the relationship between intraoperative graft flow and radiological hyperperfusion was analyzed.

Results

Significant differences were observed between the radiological hyperperfusion and nonradiological hyperperfusion groups in terms of intraoperative graft flow of both the branch (median 72 vs. 42 mL/min, respectively; p < 0.01) and main trunk (median 113 vs. 68 mL/min, respectively; p < 0.01). A receiver-operating characteristic analysis was performed to test the utility of intraoperative flow as a quantitative measure. We set the cutoff values for the intraoperative branch and main trunk flow at 57 mL/min (sensitivity: 0.707, specificity: 0.702; area under the curve [AUC]: 0.773; 95% confidence interval [CI]: 0.675–0.871) and 84 mL/min (sensitivity: 0.667, specificity: 0.771; AUC: 0.78; 95% CI: 0.685–0.875), respectively.

Conclusions

Measuring intraoperative graft flow during bypass surgery may be an effective means of predicting hyperperfusion and could serve to facilitate early therapeutic intervention such as strict blood pressure control.

Matching Selection of Donor-Recipient Vessels in Revascularization Surgery Effectively Reduce the Incidence of Postoperative Hyperperfusion Syndrome in Adult Moyamoya Disease: A Retrospective Comparison Study

INTRODUCTION

Cerebral hyperperfusion syndrome (CHS) is one of the most serious complications after revascularization surgery in patients with moyamoya disease (MMD). However, there are few effective measures to prevent the occurrence of CHS.

OBJECTIVE

The present study aims to examine the effect of the method about matching selection of donor-recipient vessels during revascularization surgery on the incidence of postoperative CHS in adult MMD patients.

METHODS

216 Chinese adult patients with MMD received surgery treatment between January 2018 and December 2019 in our hospital were enrolled in this study. 191 out of 216 patients were included in this study. Matching selection method was defined as follows: (1) blood flow: the direction of blood flow and speed of the donor artery and potential receptor arteries were measured by flow 800 indocyanine green video angiography; (2) vascular diameter: the diameters of the donor artery and potential receptor arteries by a miniature ruler. Only the artery with antegrade flow and with smallest difference in flow speed and diameter with the donor artery will be selected as the receptor artery to perform anastomosis. Matching selection was performed from January 2019. Digital subtraction angiography was performed in all patients for initial MMD diagnosis. Perioperative cerebral perfusion and related clinical symptoms were monitored. Clinical characteristics, contralateral progression, and risk factors were reviewed. The incidence of CHS and the correlation of CHS with baseline characteristics or clinical conditions were analyzed.

RESULTS

Of these 191 patients, 82 patients received matching selection of donor-recipient vessels during revascularization surgery and 109 patients without. The postoperative CHS incidence in the matching group was 3.66%, which was much lower than that in the nonmatching group (15.60%). Multivariate analysis did not reveal a significant risk factor between the progression group and the nonprogression group. Correlation analysis revealed only the matching selection method was significantly associated with the reduced postoperative CHS incidence in MMD patients.

CONCLUSIONS

The matching selection of donor-recipient vessels during revascularization surgery effectively reduces the incidence of postoperative CHS in adult patients with MMD.

A Case of Delayed Intraparenchymal Hemorrhage Due to Hyperperfusion After Flow Diverter Treatment

Delayed intraparenchymal hemorrhage (DIPH) is one of the complications of flow diverter (FD) treatment, however, the mechanism is unclear. We present the case of a 54-year-old woman with a partially thrombosed large internal carotid artery aneurysm. She presented intraparenchymal hemorrhage in the right parietal lobe three days after the successful FD treatment. We performed endoscopic hematoma removal, and then her consciousness disturbance was fully recovered. IMP single-photon emission computed tomography showed significant increase of cerebral blood flow in the right hemisphere. We diagnosed DIPH associated with hyperperfusion after FD treatment. It is necessary to consider that DIPH due to hyperperfusion may occur after FD treatment.

Characteristic Renal Histology of a 81-Year-Old Patient with a 30-Year History of Diabetes Mellitus: A Case Report

A renal histology of an 81-year-old man with a 30-year history of diabetes mellitus (DM), as well as diabetic retinopathy and neuropathy, was examined. The patient’s blood pressure was controlled within the normal range (less than 140/75 mmHg) using antihypertensive agents including angiotensin receptor blocker. Edematous management was achieved by a strict salt diet (less than 6 g/per day). However, this patient’s glycemic control was poor with HbA1c 8–10%. Serum creatinine was 0.87 mg/dL and estimated globular filtration rate (eGFR) was 64 ml/min/1.73m². Urinary protein excretion was 1.5 g/day. This patient’s renal biopsy showed linear staining for IgG along the GBM by immunofluorescence microscopy, but light microscopy showed almost intact glomeruli, and the GBM was not thickened as revealed by electron microscopy with a width of 288–368 nm (< 430 nm). While arteriolar hyalinosis was severe, and polar vasculosis was observed around the glomerular vascular pole. This case indicates that long-standing hyperglycemia may induce polar vasculosis by the mechanism of angiogenesis, but diabetic glomerulopathy can become minor change, only when hypertension and edematous management could be controlled strictly.

Uni-hemispheric hyperperfusion in the early postictal state: case report

Background

In the emergency setting of acute ischemic stroke, seizures have been reported in up to 4% of patients. In the absence of arterial occlusion, seizures may also cause abnormalities in CT perfusion in 78% of cases when the time window from onset to imaging is short. Both hyperperfusion and hypoperfusion in the postictal state have been described. Also, though rarely reported, postictal perfusion changes can be uni-hemispheric. In these cases, perfusion maps should be analyzed thoroughly, since perfusion reconstruction software relies heavily on a “normal” contralateral perfusion status.

Case presentation

A 39-year-old man was found on the ground with a minor head injury. On admission, his reactions were generally slow, but there were no other neurological symptoms, and blood pressure was low. The patient had a history of primary generalized epilepsy and admitted to dropping off his anti-epileptic medication. He was transferred to the radiological department for imaging but shortly before began to experience generalized onset tonic-clonic seizures which were brought under control by intravenous therapy with 10 mg diazepam. After approximately 15 min, a multimodal CT scan was performed, revealing marked changes in the perfusion of the brain hemispheres and posterior fossa, with sharp delimitation at the midline. Blood gas analysis was congruent with respiratory acidosis. Clinically, the patient remained awake without developing any new symptoms. He gradually recovered over the following 3 h and, against our medical recommendation, discharged himself from the hospital.

Conclusions

To the authors’ knowledge, this is the first report of an early postictal state describing sharply delimited uni-hemispheric hyperperfusion and hemispheric alteration of the cerebellum with an equally split rhombencephalon. Surprisingly, these changes were not associated with any focal neurological signs. To prevent misdiagnosis of perfusion alterations in seizures, radiologists and neurologists should be aware of the limitations of CT perfusion maps and software reconstructions. Novel use of CT perfusion reconstruction using peak enhancement helped in identifying the cerebral pathology.

Crossed cerebellar diaschisis as an indicator of severe cerebral hyperperfusion after direct bypass for moyamoya disease

Cerebral hyperperfusion (HP) complicates the postoperative course of patients with moyamoya disease (MMD) after direct revascularization surgery. Crossed cerebellar diaschisis (CCD) has been considered to be rarely associated with HP after revascularization surgery. This study aimed to describe the clinical features and factors associated with CCD secondary to cerebral HP after revascularization surgery for MMD. We analyzed 150 consecutive hemispheres including 101 in adults and 49 in pediatric patients who underwent combined direct and indirect bypass for MMD. Using single-photon emission computed tomography (SPECT), serial cerebral blood flow (CBF) was measured immediately after the surgery and on postoperative days 2 and 7. Pre- and postoperative voxel-based analysis of SPECT findings was performed to compare the changes in regional CBF. Multivariate logistic regression analysis was performed to test the effect of multiple variables on CCD. Asymptomatic and symptomatic HP was observed in 41.3% (62/150) and 16.7% (25/150) of the operated hemispheres, respectively. CCD was observed in 18.4% (16/87) of these hemispheres with radiological HP. Multivariate analysis revealed that the occurrence of CCD was significantly associated with symptomatic HP (p = 0.0015). Voxel-based analysis showed that the CBF increase in the operated frontal cortex, and the CBF reduction in the contralateral cerebellar hemisphere on day 7 were significantly larger in symptomatic HP than in asymptomatic HP (median 11.3% vs 7.5%; - 6.0% vs - 1.7%, respectively). CCD secondary to postoperative HP is more common than anticipated in MMD. CCD could potentially be used as an indicator of severe postoperative HP in patients with MMD.

Effect of Unilateral Carotid Artery Stenting on Cognitive Function in Patients with Severe Bilateral Stenosis

CASE DESCRIPTION

An 82-year-old man with dementia, gait disturbance, and a small cerebral infarction owing to severe bilateral carotid artery stenosis was successfully treated with carotid artery stenting (CAS). Preoperative cerebral vascular reactivity was reduced in the bilateral cerebral hemispheres. We performed CAS to treat right internal carotid artery stenosis. Following CAS, cerebral vascular reactivity showed an increase in the bilateral cerebral hemispheres. Memory, fluency, and attention also showed improvement.

CONCLUSIONS

This case illustrates the potential benefit of single-stage CAS for cognitive function in severe bilateral carotid artery stenosis without hyperperfusion syndrome.

Focal hyperemia in Wernicke's encephalopathy: a preliminary arterial spin labeling MRI study

Although a perturbed cerebral blood flow (CBF) has been reported in patients with Wernicke's encephalopathy (WE), its clinical meaning is still elusive. A retrospective analysis of 10 patients (male, 6; mean age, 57.7 years) with WE between October 2012 and May 2018 was performed. Brain imaging was performed using fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), arterial spin labeling (ASL) perfusion-weighted imaging (PWI), and contrasted enhanced T1-weighted imaging. All patients had symmetric high signal intensity lesions in the vulnerable areas on FLAIR or DWI with focal hyperintensity on ASL-PWI (100% sensitivity). CBF_lesion was variable (from 70 mL/100 g/min to 190.0 mL/100 g/min). CBF_lesion/CBF_{white matter} was elevated, ranging from 2.5 to 5.5. Focal hyperintensity on ASL in the vulnerable areas can be a diagnostic clue for WE.

Predictors of Impaired Cerebral Perfusion After Flow Diversion Therapy

BACKGROUND

Flow-diverting stents (FDS) are relatively safe and highly efficacious in treating cerebral aneurysms; however, a small subset of patients experience devastating hemorrhagic complications owing to presumed alterations in local aneurysm and distal cerebral blood flow. The downstream effects of FDS on distal cerebral blood flow is not well understood, but isolated reports of hyperperfusion injury have been described in the literature. We investigate the incidence and clinical factors contributing to abnormal cerebral blood flow after FDS placement.

METHODS

A retrospective analysis of patients undergoing FDS for elective aneurysm treatment between 2014-2017 was performed. Patients who underwent perfusion imaging within 24-hours posttreatment were included for further analysis. Univariate and multivariate analyses were performed to assess the impact of multiple variables on the postoperative perfusion changes.

RESULTS

A total of 69 patients underwent FDS therapy to treat unruptured intracranial aneurysms. Thirteen patients (18.8%) developed abnormal perfusion changes. A significant difference of the median was found in aneurysm projection width, depth, neck width, calculated approximate volume, and size ratio between the hypoperfused, normal, and hyperperfusion cases. On multivariate analysis, history of smoking (P = 0.0117), and approximate calculated volume (P = 0.0145) were significant predictors of hyperperfusion identified on posttreatment imaging.

CONCLUSIONS

This study yielded several novel findings. We demonstrate that cerebral blood flow alterations will occur in a significant subset of patients undergoing FDS treatment. We also provide new evidence that aneurysm volume and history of smoking may predict the developing of postoperative perfusion anomalies. Future studies are needed to evaluate the clinical ramifications of cerebral blood flow disruption in large prospective studies.

In vivo demonstration of blood-brain barrier impairment in Moyamoya disease

BACKGROUND

Moyamoya disease (MMD) is a cerebrovascular disorder characterized by fragile vascular system. Previous studies suggested that the blood-brain barrier (BBB) destabilizing cytokine angiopoietin-2 plays a critical role in increasing vascular plasticity and endothelial disintegration in MMD. The aim of this study was to assess cerebrovascular integrity in vivo in patients affected by MMD.

METHODS

We retrospectively analyzed 11 patients that underwent bypass for MMD (MMD group), 11 patients that underwent bypass for atherosclerotic cerebrovascular disease (ACVD-control group I), and 5 patients that underwent clipping for unruptured aneurysms (non-ischemic-control group II). Sodium fluorescein (NaFL) extravasation was evaluated during videoangiography when checking for bypass patency. A grading system (0, +, ++, +++) was used to define the extent of extravasation. Frequency and intensity of leakage was compared among different groups.

RESULTS

NaFL extravasation appeared in 10/11 (91%) patients with MMD and in 8/11 (73%) patients with ACVD during bypass procedures. Extravasation was observed in none of the patients undergoing clipping for unruptured aneurysms. Although both chronic ischemic patient groups showed a comparably high incidence of NaFL extravasation, the MMD group was characterized by a much greater intensity of NaFL extravasation (grade +++ in 82%) than the ACVD group (grade +++ in 27%, p < 0.05).

CONCLUSIONS

We demonstrate blood-brain barrier impairment in MMD patients for the first time in vivo. This may be due to mechanisms intrinsic to the unique pathology of MMD, probably explaining the higher association with hemorrhage and post-operative hyperperfusion.

Carotid Artery Stenting for Symptomatic Internal Carotid Artery Stenosis Associated with Moyamoya Disease

BACKGROUND

Surgical intervention in a case of internal carotid artery stenosis with moyamoya vessels has not been well described. We present a case with detailed description of the surgical procedure and perioperative management.

CASE DESCRIPTION

A 58-year-old man with symptomatic internal carotid artery stenosis had concurrent moyamoya vessels intracranially. He had motor weakness and numbness in the left upper extremity. Magnetic resonance imaging showed an ischemic lesion in the right frontal lobe and right chronic subdural hematoma. On day 18 after surgery for subdural hematoma, carotid artery stenting was performed under proximal balloon protection and distal filter protection. After carotid artery stenting, systolic blood pressure was maintained at <120 mm Hg. Hyperperfusion syndrome or hemorrhagic complication did not occur. The patient was discharged without any neurologic deficits.

CONCLUSIONS

In our patient with internal carotid artery stenosis with moyamoya vessels, strict control of blood pressure likely contributed to prevention of hyperperfusion syndrome or hemorrhagic complications.

Factors of Delayed Hyperperfusion and the Importance of Repeated Cerebral Blood Flow Evaluation for Hyperperfusion After Direct Bypass for Moyamoya Disease

OBJECTIVE

Postoperative hyperperfusion is an important complication after direct bypass for moyamoya disease, which sometimes occurs late after initial postoperative cerebral blood flow (CBF) measurement. This study aimed to clarify the incidence of hyperperfusion with management using postoperative continuous sedation and repeated postoperative CBF measurement and to identify factors associated with delayed hyperperfusion.

METHODS

This retrospective study evaluated 72 consecutive hemispheres in 56 adult Japanese patients with moyamoya disease who underwent direct bypass. Postoperative continuous sedation was routinely administered based on CBF evaluation. First, the incidence of symptomatic hyperperfusion was investigated. Second, radiologic hyperperfusion (RHP), which was strictly defined as >30% increase in CBF compared with the contralateral side, and factors associated with delayed RHP were statistically analyzed.

RESULTS

Postoperative symptomatic hyperperfusion occurred in 3 hemispheres (4.2%), including subarachnoid hemorrhage in 1 hemisphere (1.4%). RHP immediately after surgery was identified in 16 hemispheres (22.2%). In 8 hemispheres (11.1%), RHP appeared or worsened several days after initial CBF study. In univariate logistic regression analysis, decreased preoperative cerebral vasoreactivity was significantly associated with delayed RHP.

CONCLUSIONS

The incidence of symptomatic hyperperfusion was 4.2% with management. Delayed hyperperfusion was significantly associated with decreased cerebral vasoreactivity. Therefore, repeated CBF measurements evaluating preoperative cerebral vasoreactivity may decrease complications.

A case of cerebellar ataxia associated with VZV infection

The varicella zoster virus (VZV) is a neurotropic virus that becomes latent in the sensory ganglia, but later causes various neurologic complications such as meningitis, encephalitis, myelitis, meningoencephalitis, cranial neuropathy, and peripheral neuropathy [1]. While acute cerebellitis is one of the most frequent acute cerebellar diseases associated with VZV in childhood, VZV rarely causes cerebellitis in adults, with or without skin manifestations, and only a few isolated cases of adult VZV cerebellitis have been reported. We report a case of acute cerebellitis associated with VZV infection after a herpetic rash in an 80-year-old male. Functional imaging of his cerebellum showed high blood perfusion during the acute stage of the disease, though perfusion decreased in the subacute stage.

Objective evaluation of cerebrovascular reactivity for acetazolamide predicts cerebral hyperperfusion after carotid artery stenting: Comparison with region of interest methods

BACKGROUND AND PURPOSE

Hemodynamic impairments are considered risk factors of cerebral hyperperfusion after carotid artery stenting (CAS); measurement by Single-photon emission computed tomography (SPECT) using a subjective region of interest (ROI) method lacks consistency and reproducibility.

MATERIALS AND METHODS

The present study compared objective perfusion analysis (stereotactic extraction estimation [SEE] method) with the ROI method for preoperative SPECT to predict the hyperperfusion phenomenon (HPP) after CAS. Preoperative resting asymmetry index (cerebral blood flow [CBF] ratio from the affected to unaffected hemisphere) and cerebrovascular reactivity (CVR) to acetazolamide were measured by N-isopropyl-p-[¹²³I]-iodoamphetamine SPECT using the SEE and ROI method in 84 patients. CBF was also measured the day after CAS. Perfusion data with the highest area under the curve (AUC) by receiver-operating characteristic (ROC) analysis was considered a perfusion risk factor of HPP. Multivariate analyses for clinical characteristics and perfusion risk factors were performed to determine predictors of HPP.

RESULTS

The HPP was observed in 10 patients (11.9%). Female sex, contralateral stenosis, and degree of stenosis were significantly associated with HPP development on univariate analysis, and symptomatic stenosis was not found to be a significant factor. On SPECT analysis, CVR in the MCA area by SEE method had the highest AUC (0.981). Multivariate analysis showed that CVR in the MCA area was a significant predictor of HPP (P=0.041). To predict hyperperfusion, the ROC curve of the CVR showed a cutoff value of -0.60%, sensitivity of 94.6%, and specificity of 100% (P<0.001).

CONCLUSIONS

Objective SEE method had better a predictive capability than ROI method to identify risk of hyperperfusion after CAS.

Comparison of Monitoring of Cerebral Blood Flow by c-FLOW and Transcranial Doppler in Carotid Endarterectomy

OBJECTIVE

To prospectively compare the use of the cerebral blood flow monitor (c-FLOW) and transcranial Doppler (TCD) as 2 techniques for assessing brain perfusion during carotid endarterectomy.

METHODS

This was a prospective, single-center, observational study. All patients were monitored using c-FLOW and TCD during the operation. Changes from baseline values of cerebral blood flow index and blood flow velocity of middle cerebral artery (V-MCA) were recorded following carotid artery clamping and unclamping. The correlation analysis was conducted for c-FLOW and TCD monitoring values.

RESULTS

Seventy-three consecutive patients were enrolled from August 2015 to March 2016. No death or stroke occurred during the postoperative hospitalization. Fresh infarction was identified on magnetic resonance imaging in 17 patients. Ten patients showed a significant decrease of V-MCA following carotid clamping. A shunt was placed for only 4. The Pearson correlation index between CFI and V-MCA was 0.647 (P < 0.001). A cut-off of 21% decrease of CFI was proposed as optimal to detect intraoperative hypoperfusion. Seven patients were diagnosed as having hyperperfusion by TCD monitoring. The Pearson correlation index between CFI and V-MCA was 0.286 (P = 0.014). A cut-off of 15% increase of CFI following carotid unclamping was suggested as optimal to detect the postoperative hyperperfusion.

CONCLUSIONS

c-FLOW could continuously and noninvasively monitor the cerebral blood flow in real-time during carotid endarterectomy and effectively detect the intraoperative hypoperfusion and postoperative hyperperfusion as defined by TCD so that it may serve as a favorable modality in future intraoperative monitoring.

First Depiction of Flow Voids to Differentiate Pituicytomas from Giant Adenomas

Pituicytomas are rare low-grade glial lesions of neurohypophysis or adenohypophysis. They are often misdiagnosed as adenomas due to their similar morphology. Previous reports have underlined their nonspecific aspect. In our experience, presence of flow voids on magnetic resonance, which usually indicate hypervascularized tumors with strong arterial supply, may be a useful sign to identify pituicytomas. Unlike adenomas, pituicytomas are highly vascularized tumors. Second, we emphasize the strong enhancement of these tumors when compared with normal hypophysis, which may be another sign of their hypervascularization. Indeed, adenomas, on the opposite side, present less enhancement than normal hypophysis. This observation is corroborated by previous histologic studies that showed adenomas present less vascular density than normal pituitary glands. However, in large tumors, the normal hypophysis can sometimes not be individualized and thus the enhancement gradient between the tumor and normal tissue cannot be properly assessed. Due to their rarity, no previous reports had ever emphasized the specific signs that could allow us to differentiate pituicytomas from adenomas; however, it seems crucial due to the potential hemorrhagic complications of pituicytoma surgery.

Characteristics of seizure-induced signal changes on MRI in patients with first seizures

PURPOSE

The aim of this study was to investigate the predictive factors and identify the characteristics of the seizure-induced signal changes on MRI (SCM) in patients with first seizures.

METHODS

We conducted a retrospective study of patients with first seizures from March 2010 to August 2014. The inclusion criteria for this study were patients with 1) first seizures, and 2) MRI and EEG performed within 24h of the first seizures. The definition of SCM was hyper-intensities in the brain not applying to cerebral arterial territories. Multivariate logistic regression was performed with or without SCM as a dependent variable.

RESULTS

Of 431 patients with seizures visiting the ER, 69 patients met the inclusion criteria. Of 69 patients, 11 patients (15.9%) had SCM. Epileptiform discharge on EEG (OR 29.7, 95% CI 1.79-493.37, p=0.018) was an independently significant variable predicting the presence of SCM in patients with first seizures. In addition, the topography of SCM was as follows; i) ipsilateral hippocampus, thalamus and cerebral cortex (5/11), ii) unilateral cortex (4/11), iii) ipsilateral thalamus and cerebral cortex (1/11), iv) bilateral hippocampus (1/11). Moreover, 6 out of 7 patients who underwent both perfusion CT and MRI exhibited unilateral cortical hyperperfusion with ipsilateral thalamic involvement reflecting unrestricted vascular territories.

CONCLUSION

There is an association between epileptiform discharges and SCM. Additionally, the involvement of the unilateral cortex and ipsilateral thalamus in SCM and its hyperperfusion state could be helpful in differentiating the consequences of epileptic seizures from other pathologies.

Staged carotid artery angioplasty and stenting for patients with high-grade carotid stenosis with high risk of developing hyperperfusion injury: a retrospective analysis of 44 cases

Background

Hyperperfusion syndrome (HPS) is a rare but potentially a life-threatening complication after carotid artery angioplasty and stenting (CAS). Staged CAS has been an alternative to prevent HPS.

Materials and methods

44 of 908 patients with high-grade internal carotid artery stenosis or near occlusion were at risk of HPS because of poor collateral flow and impaired cerebral blood flow (CBF). They were treated with first (stage 1), followed by a full CAS (stage 2) 1 month later. Their 30-day outcomes were tabulated and analysed.

Results

During follow-up, 1 of the 44 (2.2%) patients developed HPS immediately, 3 (7%) had postprocedural HPS (ie, transcranial Doppler (TCD) >120%) without clinical symptoms and 3 (7%) required stenting at stage 1 for carotid dissections. After stage 1, there were significant improvement between the preprocedural and postprocedural CBF (0.98±0.06 vs 0.85±0.05, p<0.05), mean transit time (MTT; 1.05±0.05 vs 1.15±0.05, p<0.05), time to peak (TTP; 1.04±0.06 vs 1.20±0.06, p<0.05) on CT perfusion (CTP), and CBF (66.41±7.41 vs 44.44±6.43, p<0.05) on TCD. After stage 2, improvement was seen in CBF (1.01±0.07 vs 0.98±0.06, p<0.05), MTT (1.01±0.05 vs 1.05±0.05, p<0.05), TTP (0.99±0.06 vs 1.04±0.06, p<0.05) on CTP and CBF (66.41±7.41 vs 93.78±18.81, p<0.05) on TCD. 2 had postoperative increase of middle cerebral artery mean flow velocity of 120% after stage 2 without clinical symptoms.

Conclusion

Staged carotid artery stenting probably decreased the chance of developing HPS in this group of selected patients. Although requiring a 2-step intervention, staged CAS may be a safe and effective alternative.

Evaluation of Cerebral Hyperperfusion After Carotid Artery Stenting Using C‑Arm CT Measurements of Cerebral Blood Volume

PURPOSE

Hyperperfusion syndrome (HPS) after carotid artery stenting (CAS) causes serious symptoms; therefore, early evaluation after CAS is considered to be important. Measurement of cerebral blood volume using C‑arm computed tomography (C-arm CBV) has recently become possible. Here, the usefulness of C‑arm CBV for the evaluation of hyperperfusion was investigated.

METHODS

C-arm CBV was measured before and immediately after CAS in 30 patients. The regions of interest (ROI) were set in the bilateral middle cerebral artery perfused regions, and the affected/healthy side ratio of measured C‑arm CBV (CBV ratios) was determined to evaluate cerebral perfusion. For comparing values before and after CAS, the CBV ratio increase rate (postoperative CBV ratios/preoperative CBV ratios) was also determined.

RESULTS

C-arm CBV was successfully measured in 30 patients. Intracerebral hemorrhage (ICH) was detected in 3 patients, and no other patient had hyperperfusion syndrome. In the patients who developed ICH, postoperative C‑arm CBV on the affected side was high, and a marked increase was confirmed in the postoperative CBV ratios. Postoperative CBV ratios were 1.03 ± 0.40 and 1.45 ± 0.68 in the non-ICH and ICH groups, and CBV ratio increase rates were 2.7 ± 24.0% and 28.5 ± 26.7% in the non-ICH and ICH groups, respectively; these differences were statistically significant (P < 0.01).

CONCLUSION

C-arm CT allows CBV measurements immediately after CAS without requiring transport of the patient out of the angiography room, and it may enable the evaluation of hyperperfusion before and after CAS.

Hyperperfusion syndrome after aneurysm surgery: a case report

A 74-year-old woman exhibited sensory aphasia with abrupt blood pressure elevation 3 h after clipping of an unruptured large left middle cerebral artery aneurysm. Perfusion computed tomography and single-photon emission computed tomography demonstrated hyperperfusion in one of the distal parent artery areas. She gradually improved and was discharged without neurological deficits. Increased distal blood flow after occlusion of the large cerebral aneurysm and postischemic reperfusion after temporary occlusion of the parent artery during surgery presumably played an important role in the occurrence of this fairly rare condition associated with aneurysm surgery.

Severe and prolonged ictal paresis in an elderly patient

We report an 84-year-old female who showed a rare manifestation of epilepsy, ictal paresis, a type of simple partial seizure presenting with focal motor dysfunction. While the patient exhibited severe left hemiplegia which lasted for a week, cranial diffusion-weighted MRI demonstrated slightly high intensity in the right posterior quadrant, and electroencephalography (EEG) showed continuous epileptiform discharges located mainly in the right parieto-occipital area, strongly suggesting that the patient was in an ictal state. ^99mTc-hexamethylpropylene amine oxime-single photon emission computed tomography (HMPAO-SPECT) showed markedly high blood perfusion in the right parieto-temporo-occipital areas. Considering the distribution of EEG epileptiform activities and HMPAO-SPECT hyperperfusion, it is most likely that the ictal paresis of our patient was associated with epileptic activities at the sensorimotor area which caused either direct or indirect activation of an inhibitory system. Careful clinical consideration of the possibility of ictal paresis is needed in elderly patients, especially in those with preexisting dementia, because paresis can be as severe as complete flaccid hemiplegia and can last as long as for a week.

Dilation of the Internal Carotid Artery at the Entrance to the Carotid Canal following Carotid Artery Stenting Predicts Postprocedural Hyperperfusion

OBJECTIVE

Ischemic stroke and hyperperfusion (HP) are the most frequent and important complications in carotid artery stenosis surgery. Carotid artery stenting (CAS) has replaced carotid endarterectomy in high medical risk patients. Prior to CAS, initial angiographic findings disclose a small caliber internal carotid artery (IC) due to stenosis, but after the stenosis is relieved, the diameter of the IC becomes enlarged. We investigated whether a change in the IC diameter was related to ischemic complication and HP using cerebral blood flow single photon emission computed tomography (SPECT).

METHODS

From February 2008 to December 2009 we consecutively performed 39 CAS on 35 patients. We retrospectively analyzed the relationship between changes at the level before the entry to the petrous bone canal of the IC and stenosis of the etiological artery, improvement in stenosis, HP and postintervention diffusion-weighted image high-intensity lesions. Statistical analyses comprised Wilcoxon/Kruskal-Wallis analysis, analysis of variance and a multivariate logistic analysis.

RESULTS

A total of 9 cases showed HP in SPECT. Severity of IC stenosis and change in the IC at the level before the entry to the petrous bone canal were related with statistical significance to HP. Other factors did not correlate with HP.

CONCLUSION

Procedure-related dilation of the IC at the level before the entry to the petrous bone canal occurred due to release of the etiological stenosis. This finding can also support the prediction of HP.

Post-carotid endarterectomy cerebral hyperperfusion syndrome : is it preventable by strict blood pressure control?

Objective

Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid endarterectomy (CEA). However, the prevalence of CHS has decreased as techniques have improved. This study evaluates the role of strict blood pressure (BP) control for the prevention of CHS.

Methods

All 18 patients who received CEA from February 2009 through November 2012 were retrospectively reviewed. All patients were routinely managed in an intensive care unit by a same protocol. The cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow (rCBF) study by perfusion computed tomography (pCT) and mean velocity by transcranial doppler (TCD). BP was strictly controlled (<140/90 mm Hg) for 7 days. When either post-CEA hyperperfusion (>100% increase in the rCBF by pCT or in the mean velocity by TCD compared with preoperative values) or CHS was detected, BP was maintained below 120/80 mm Hg.

Results

TCD and pCT data on the patients were analyzed. Ipsilateral rCBF was significantly increased after CEA in the pCT (p=0.049). Post-CEA hyperperfusion was observed in 3 patients (18.7%) in the pCT and 2 patients (12.5%) in the TCD study. No patients developed clinical CHS for one month after CEA. Furthermore, no patients developed additional neurological deficits related to postoperative cerebrovascular complications.

Conclusion

Intensive care with strict BP control (<140/90 mm Hg) achieved a low prevalence of post-CEA hyperperfusion and prevented CHS. This study suggests that intensive care with strict BP control can prevent the prevalence of post-CEA CHS.

Inhalation of hydrogen gas reduces liver injury during major hepatotectomy in swine

AIM: To study the effect of H₂ gas on liver injury in massive hepatectomy using the Intermittent Pringle maneuver in swine.

METHODS: Male Bama pigs (n = 14) treated with ketamine hydrochloride and Sumianxin II as induction drugs followed by inhalation anesthesia with 2% isoflurane, underwent 70% hepatotectomy with loss of bleeding less than 50 mL, and with hepatic pedicle occlusion for 20 min, were divided into two groups: Hydrogen-group (n = 7), the pigs with inhalation of 2% hydrogen by the tracheal intubation during major hepatotectomy; Contrast-group (n = 7), underwent 70% hepatotectomy without inhalation of hydrogen. Hemodynamic changes and plasma concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA) in liver tissue were measured at pre-operation, post-hepatotectomy (PH) 1 h and 3 h. The apoptosis and proliferating cell nuclear antigen (PCNA) expression in liver remnant were evaluated at PH 3 h. Then we compared the two groups by these marks to evaluate the effect of the hydrogen in the liver injury during major hepatotectomy with the Pringle Maneuver in the swine.

RESULTS: There were no significant differences in body weight, blood loss and removal liver weight between the two groups. There was no significant difference in changes of portal vein pressure between two groups at pre-operation, PH 30 min, but in hydrogen gas treated-group it slightly decrease and lower than its in Contrast-group at PH 3 h, although there were no significant difference (P = 0.655). ALT and AST in Hydrogen-group was significantly lower comparing to Contrast-group (P = 0.036, P = 0.011, vs P = 0.032, P = 0.013) at PH 1 h and 3 h, although the two groups all increased. The MDA level increased between the two group at PH 1 h and 3 h. In the hydrogen gas treated-group, the MDA level was not significantly significant at pre-operation and significantly low at PH 1 h and 3 h comparing to Contrast-group (P = 0.0005, P = 0.0004). In Hydrogen-group, the HA level was also significantly low to Contrast-group (P = 0.0005, P = 0.0005) although the two groups all increased at PH 1 h and 3 h. The expression of cluster of differentiation molecule 31 molecules Hydrogen-group was low to Contrast-group. However, PCNA index (%) was not statistically significant between the two groups (P = 0.802). Microphotometric evaluation of apoptotic index (AI) in terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-stained tissue after hepatotectomy for 3h, the AI% level in the hydrogen was significantly low to Contrast-group (P = 0.012). There were no significant difference between Hydrogen-group and Contrast-group at pre-operation (P = 0.653, P = 0.423), but after massive hepatotectomy, the TNF-α and IL-6 levels increase, and its in Hydrogen-group was significantly low compared with Contrast-group (P = 0.022, P = 0.013, vs P = 0.016, P = 0.012), respectively. Hydrogen-gas inhalation reduce levels of these markers and relieved morphological liver injury and apoptosis.

CONCLUSION: H₂ gas attenuates markedly ischemia and portal hyperperfusion injury in pigs with massive hepatotectomy, possibly by the reduction of inflammation and oxidative stress, maybe a potential agent for treatment in clinic.