Waveform Analysis of STA-MCA Bypass graft in Revascularization Surgery for Moyamoya Disease.

BACKGROUND: Postoperative hyperperfusion syndrome (PHS) is a well-known complication following superficial temporal artery (STA)-middle cerebral artery (MCA) bypass for moyamoya disease (MMD). The early detection of postoperative radiological hyperperfusion (PRH), characterized by a transient increase in local cerebral blood flow (CBF), is crucial for the early diagnosis of PHS. This study aimed to investigate the effectiveness of waveform analysis for early PRH detection. METHODS: We reviewed 52 consecutive patients who underwent STA-MCA bypass for MMD. Patients were divided into PRH and non-PRH groups based on the postoperative/preoperative CBF ratio. We collected the intraoperative bypass graft waveform and bypass flow data using a flowmeter. The pulsatile index (PI), an indicator of peripheral vascular resistance (PVR), was calculated from bypass flow data. Next, the newly proposed index of PVR, the ratio of the time from peak to 50% decay and to 100% decay (RT50), was calculated through waveform analysis. The values were then compared between the PRH and non-PRH groups. RESULTS: Twenty-seven of the 52 patients met the inclusion criteria. Fourteen of these 27 patients showed PRH. The RT50, but not the PI, was significantly higher in the PRH group. Linear regression analysis revealed a significant correlation between the RT50 and PI. In the receiver operating characteristic for predicting PRH, the area under the curve of RT50 was 0.750, with a cutoff value of 0.255, a sensitivity of 0.928, and a specificity of 0.500. CONCLUSIONS: The RT50 obtained from waveform analysis is associated with PVR and can be useful for the early detection of PRH in patients with MMD.

Hemifacial spasm associated with posterior inferior cerebellar artery aneurysm: illustrative case.

BACKGROUND: Hemifacial spasms (HFSs) complicated by intracranial aneurysms are rare. Recently, endovascular treatment has been widely used for this disease entity and can allow the cessation of intracranial aneurysm arterial pulsation, leading to recovery from the HFS. Here, the authors present a case of HFS associated with an ipsilateral posterior inferior cerebellar artery (PICA) aneurysm successfully treated with open surgery. OBSERVATIONS: A 68-year-old woman was annually followed-up for an incidentally found right PICA aneurysm. Over 3 years, the PICA aneurysm gradually increased in size, which eventually led to right HFS. An axial fast spoiled gradient-recalled echo sequence with gadolinium enhancement showed the PICA aneurysm compressing the root exit zone (REZ), which was attributed as the cause of the HFS. However, a fusion image of the three-dimensional T1-weighted fast spin-echo sequence and magnetic resonance angiogram clearly showed a direct contact between the REZ and the anterior inferior cerebellar artery (AICA), which was located at the apex of the PICA aneurysm. Intraoperatively, the AICA was found compressing the REZ; hence, microvascular decompression with aneurysmal clipping was performed. The HFS resolved immediately after surgery. LESSONS: In cases of HFS associated with an ipsilateral intracranial aneurysm, a detailed neuroradiological assessment to identify the responsible lesion is important to use the most optimal treatment of choice.

The use of vessel wall imaging to detect a de novo microaneurysm on the periventricular anastomoses in moyamoya disease: illustrative case.

BACKGROUND: Moyamoya disease (MMD) is linked to the formation of intracranial aneurysms. The authors recently observed an effective use of magnetic resonance vessel wall imaging (MR-VWI) to detect de novo unruptured MMD-associated microaneurysms. OBSERVATIONS: The authors describe a 57-year-old female who was diagnosed with MMD 6 years ago after suffering a left putaminal hemorrhage. MR-VWI revealed point-like enhancement in the right posterior paraventricular region during the annual follow-up. On the T2-weighted image, this lesion was surrounded by high intensity. Angiography revealed a microaneurysm in the periventricular anastomosis. Right combined revascularization surgery was performed to prevent future hemorrhagic events. Another de novo circumferential enhanced lesion on MR-VWI appeared in the left posterior periventricular region 3 months after surgery. Angiography revealed that the enhanced lesion was a de novo microaneurysm on the periventricular anastomosis. The left combined revascularization surgery went well. The bilateral microaneurysms vanished on follow-up angiography. LESSONS: Unruptured MMD-associated microaneurysms on the periventricular anastomosis can be detected using MR-VWI. Revascularization surgery can eliminate microaneurysms by reducing hemodynamic stress on the periventricular anastomosis.

Bypass surgery for ruptured dissecting aneurysms of the proximal posterior cerebral artery: illustrative case.

BACKGROUND: Posterior cerebral artery (PCA) dissecting aneurysms commonly occur in the proximal PCA and are considered rare. The treatment of proximal PCA dissecting aneurysms is challenging because of the existence of perforators supplying the vital neural structures. Recently, endovascular intervention has been used; however, concerns for ischemic or hemorrhagic complications exist. OBSERVATIONS: A 54-year-old woman presented with subarachnoid hemorrhage due to dissecting aneurysm rupture at the P1-P2 junction of the PCA. The thalamoperforating artery (TPA) and medial posterior choroidal artery (MPchA) originated from the proximal end and the distal end of the aneurysm, respectively. Additionally, the posterior communicating artery (PcomA) connected with the dissected segment. To preserve these perforators, we performed surgical trapping combined with superficial temporal artery (STA) PCA anastomosis. Clips were applied for trapping the proximal and distal end of the aneurysm, with preservation of the TPA and MPchA origin. PcomA was left open for blood flow preservation to the perforators directly arising from the aneurysm. The postoperative course was uneventful, and the patient was discharged. LESSONS: Surgical trapping using STA-PCA bypass could be a treatment of choice for proximal PCA dissecting aneurysms, considering its potential for cure and prevention of ischemic complications.

[Cerebral Blood Vessels and Infection].

Infectious intracranial aneurysms(IIAs)are rare cerebrovascular complications of systemic infections induced by microbial infiltration and degradation of the arterial vessel wall. Prospective or population-wide studies of the epidemiology, natural history, or management of IIAs have not been conducted. In this study, we present the epidemiological and angiographical features, management, and outcomes of IIAs based on published case series and retrospective studies. Most IIAs were small in size(< 5 mm), with aneurysms located in the middle cerebral artery followed by the posterior cerebral artery. Endovascular interventions for IIAs have increased since coils, liquid embolic materials, and microcatheter became more sophisticated, allowing them to reach more distal branches. Open surgery is still required in cases with large clots or in cases involving branches feeding the eloquent areas, which cannot be sacrificed. These multimodal approaches for managing IIAs have achieved satisfactory results. Septic cavernous sinus thrombosis is also a rare, life-threatening complication of head and neck infections. Several antibiotics and antivirals are used in combination with anticoagulants. However, no consensus has been reached because of a lack of randomized controlled trials and large population-based studies.

Transient Global Cerebral Hypoperfusion as a Characteristic Cerebral Hemodynamic Pattern in the Acute Stage after Combined Revascularization Surgery for Pediatric Moyamoya Disease: N-Isopropyl-P-[123I] Iodoamphetamine Single-Photon Emission Computed Tomography Study.

INTRODUCTION: Surgical revascularization prevents cerebral ischemic attack by improving cerebral blood flow (CBF) in both adult and pediatric patients with moyamoya disease (MMD). Uneven hemodynamic changes, including local cerebral hyperperfusion and remote ischemia, can cause delayed intracerebral hemorrhage and perioperative infarctions in adult MMD patients, but the characteristic hemodynamic pattern among pediatric MMD patients after revascularization surgery is poorly understood. METHODS: This study included 16 consecutive pediatric MMD patients (age, 6-16 years; mean age, 11.3) undergoing superficial temporal artery-middle cerebral artery anastomosis combined with encephalo-duro-myo-synangiosis on 21 affected hemispheres. Perioperative management was conducted by aspirin administration and strict blood pressure control (110-130 mm Hg). We prospectively performed N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography on postoperative days (POD) 1 and 7 and analyzed the temporal changes in perioperative hemodynamics. RESULTS: Four patients (19.0%, 4/21) exhibited immediate CBF improvement from POD 1, which was classified as "immediate redistribution pattern." In contrast, 9 (42.9%, 9/21) demonstrated transient hemispheric global hypoperfusion at POD 1 and subsequent CBF improvement at POD 7, which was defined as "transient hypoperfusion pattern." Although 8 patients, including 4 with "transient hypoperfusion pattern" (44.4, 4/9), developed mild transient neurological deterioration in the acute stage, it resolved in all 21 patients, and there were no permanent neurological deficits. DISCUSSION/CONCLUSIONS: This study revealed that the "transient hypoperfusion pattern" after revascularization surgery is relatively common among pediatric MMD patients, and its outcome is favorable under strict perioperative management.

[How to Avoid Intraoperative Rupture and What to Do When It Ruptures].

Intracranial aneurysm rupture is the main fatal complication of coil embolization for an intracranial aneurysm performed in conjunction with systemic heparinization. We answered five clinical questions about anesthesia, systemic heparinization, intraoperative aneurysmal rupture, the balloon-assisted technique, and the next step of initial response in case of aneurysmal rupture. It is crucial to understand when and why intraoperative aneurysmal rupture occurs to reduce its mortality rate. In cases of intraoperative problems, never pull the microcatheter or coil when perforating an aneurysm; lowering blood pressure, administering protamine for the reversal of heparin, and occluding blood flow into an aneurysm by inflating balloon(s) will help in the treatment. It is our pleasure that this chapter will help in your daily care.

Persistent Local Vasogenic Edema with Dynamic Change in the Regional Cerebral Blood Flow after STA-MCA Bypass for Adult Moyamoya Disease.

We report an adult moyamoya disease (MMD) patient who developed persistent local vasogenic edema with dynamic change in the regional cerebral blood flow after left superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. A 49-year-old woman with ischemic-onset MMD underwent left STA-MCA anastomosis. Magnetic resonance (MR) imaging of fluid-attenuated inversion recovery 1 day after surgery revealed an asymptomatic local high-signal-intensity lesion at the site of anastomosis, and MR angiography demonstrated apparently patent STA-MCA bypass. Due to the increased apparent diffusion coefficient value, we diagnosed the lesion as vasogenic edema. A significant increase in focal cerebral blood flow (CBF) at the site of the anastomosis was observed on N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography (123I-IMP-SPECT) (139.8%; compared with the preoperative value). Under strict blood pressure control (systolic blood pressure under 130 mmHg), the patient remained asymptomatic during the entire peri-operative period, but the 123I-IMP-SPECT 7 days after surgery suggested paradoxical CBF decrease (72.9%). Based on this finding, we allow the patient to be maintained under normotensive condition (∼160 mmHg), which recovered the CBF (115.0%) 14 days after surgery. Vasogenic edema remained during the entire peri-operative period, but completely disappeared 83 days after surgery. Local vasogenic edema formation due to cerebral hyperperfusion is not uncommon after STA-MCA anastomosis for adult MMD, but dynamic CBF change at the site of persistent local vasogenic edema after STA-MCA anastomosis is extremely rare. We recommend serial CBF measurement in the acute stage after revascularization surgery for MMD, especially when MR imaging demonstrates local signal intensity change.

Temporal profile of magnetic resonance angiography and decreased ratio of regulatory T cells after immunological adjuvant administration to mice lacking RNF213, a susceptibility gene for moyamoya disease.

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease with an unknown etiology and is characterized by an abnormal vascular network at the base of the brain. Recent studies identified the RNF213 gene (RNF213) as an important susceptibility gene for MMD; however, the mechanisms underlying the RNF213 abnormality related to MMD have not yet been elucidated. We previously reported that Rnf213-deficient mice and Rnf213 p. R4828K knock-in mice did not spontaneously develop MMD, indicating the importance of secondary insults in addition to genetic factors in the pathogenesis of MMD. The most influential secondary insult is considered to be an immunological reaction because RNF213 is predominantly expressed in immunological tissues. Therefore, we herein attempted to evaluate the role of an immunological stimulation as a supplementary insult to the target disruption of RNF213 in the pathophysiology of MMD. Rnf213-deficient mice were treated with strong immunological adjuvants including muramyl dipeptide (MDP)-Lys (L18), and then underwent time-sequential magnetic resonance angiography (MRA) up to 40 weeks of age. The results obtained did not reveal any characteristic finding of MMD, and no significant difference was observed in MRA findings or the anatomy of the circle of Willis between Rnf213-deficient mice and wild-type mice after the administration of MDP-Lys (L18). The ratio of regulatory T cells after the administration of MDP-Lys (L18) was significantly decreased in Rnf213-deficient mice (p<0.01), suggesting the potential role of the RNF213 abnormality in the differentiation of regulatory T cells. Although the mechanisms underlying the development of MMD currently remain unclear, the RNF213 abnormality may compromise immunological self-tolerance, thereby contributing to the development of MMD.

Transient middle cerebral artery occlusion in mice induces neuronal expression of RNF213, a susceptibility gene for moyamoya disease.

Although recent genome-wide and locus-specific association studies revealed that the RING finger protein 213 (RNF213) gene is an important susceptibility gene for moyamoya disease (MMD), the exact mechanism by which the genetic alteration of RNF213 contributes to the development of MMD has not yet been elucidated. A quantitative reverse transcription polymerase chain reaction (PCR) analysis revealed that the constitutive expression of the RNF213 gene was very low in adult and embryonic brain tissue. However, information regarding the temporal and spatial expression patterns of the RNF213 gene under the condition of cerebral ischemia, which is one of characteristic pathologies associated with MMD, is currently limited. In order to address this critical issue, Rnf213 mRNA expression was investigated in mouse brains subjected to 60 min of transient middle cerebral artery occlusion (tMCAO). Male C57BL6/j mice underwent tMCAO through the intraluminal blockade of MCA. Expression of the Rnf213 gene in the tMCAO brain was investigated with in situ RNA hybridization and a real-time PCR analysis from 1 to 72 h after tMCAO. In situ RNA hybridization revealed a significant increase in Rnf213 mRNA levels in the cerebral cortex supplied by the affected MCA, especially at the penumbra area, as early as 6h after tMCAO, and these levels had increased further by 24 h. Rnf213 gene expression remained unchanged in the non-ischemic hemisphere or control specimens. Double staining of Rnf213 mRNA with NeuN immunohistochemistry revealed Rnf213 hybridization signal expression mostly in neurons. The real-time PCR analysis confirmed induction of the Rnf213 gene after tMCAO. Therefore, the Rnf213 gene was up-regulated in the ischemic brain, especially at the penumbra area, 6 h after tMCAO. Early increases in RNF213 gene expression in neurons after tMCAO indicate its involvement in cerebral ischemia, which is an underlying pathology of MMD. Further investigation is required to clarify its exact role in the pathophysiology of MMD.

Temporal profile of the vascular anatomy evaluated by 9.4-tesla magnetic resonance angiography and histological analysis in mice with the R4859K mutation of RNF213, the susceptibility gene for moyamoya disease.

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease with an unknown etiology. Recent genome-wide and locus-specific association studies identified the RNF213 gene (RNF213) as an important susceptibility gene of MMD among East Asian populations; however, the mechanism by which an abnormality in RNF213 leads to MMD has not yet been elucidated. Therefore, we herein generated Rnf213-knock-in mice (RNF213-KI) expressing a missense mutation in mouse Rnf213, p. R4828K, on Exon 61, corresponding to human RNF213, p. R4859K, on Exon 60, in MMD patients, and investigated whether they developed MMD. We assessed the temporal profile of intracranial arteries by 9.4-T magnetic resonance angiography (MRA) continuously in the same mouse up to 64 weeks of age. The ratios of the outer diameter of the internal carotid artery (ICA)/basilar artery (BA) and middle cerebral artery (MCA)/BA were evaluated histopathologically. The common carotid arteries (CCA) were sectioned and arterial wall thickness/thinness was evaluated by Elastica-Masson staining before and after CCA ligation, which selectively induced vascular hyperplasia. The results obtained showed that RNF213-KI grew normally, with no significant difference being observed in MRA findings or the anatomy of the circle of Willis between homozygous RNF213-KI and wild-type (Wt) littermates. Furthermore, no significant difference was noted in the diameter of the intracranial vasculature (ICA/BA; p=0.82, MCA/BA; p=0.27) or in vascular remodeling after CCA ligation. Therefore, RNF213-KI did not spontaneously develop MMD. Multiple secondary insults such as environmental factors may contribute to the onset of MMD in addition to genetic factors.

Enhanced post-ischemic angiogenesis in mice lacking RNF213; a susceptibility gene for moyamoya disease.

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease with unknown etiology that is characterized by the development of abnormal vascular networks at the base of the brain. Recent genome-wide studies identified RNF213 as an important MMD susceptibility gene. However, the exact mechanism by which the RNF213 abnormality leads to MMD remains unknown. Thus, we sought to clarify the role of RNF213 in angiogenesis under ischemic conditions using conventional RNF213 knockout mice. We assessed the infarction volume, cerebral edema, and vascular density in the ischemic brain after transient middle cerebral artery occlusion (tMCAO). To further evaluate systemic angiogenesis following chronic ischemia, we investigated blood flow recovery using laser speckle flowmetry, the severity of ambulatory impairments, and vascular density in the hind-limb after permanent femoral artery ligation. Results were compared between homozygous RNF213 knockout mice (RNF213 -/-) and wild-type littermates (Wt). No significant differences were observed in infarction volume or the formation of edema following tMCAO, or in vascular density 28 days after tMCAO between RNF213 -/- and Wt. Blood flow recovery was significantly improved in RNF213 -/- from 3 to 28 days after femoral artery ligation, and angiogenesis as shown by vascular density in the hind-limb was significantly enhanced in RNF213 -/- at 28 days. The amelioration of ambulatory impairments was also evident in RNF213 -/-. Angiogenesis was enhanced in mice lacking RNF213 after chronic hind-limb ischemia, which suggested the potential role of the RNF213 abnormality in the development of pathological vascular networks in chronic ischemia.

Autoimmune hypophysitis presenting with intracranial multi-organ involvement: three case reports and review of the literature.

BACKGROUND: Autoimmune hypophysitis very rarely spreads to nearby organs outside the pituitary tissue, for unknown reasons, with only 5 reported cases of hypophysitis spreading over the cavernous sinus. CASE PRESENTATION: Three patients presented with cases of non-infectious hypophysitis spreading outside the pituitary tissue over the cavernous sinus. All three cases were diagnosed with histological confirmation by transsphenoidal surgery, and the patients showed remarkable improvement with postoperative pulse dose steroid therapy, including disappearance of abnormal signal intensities in the bilateral hypothalami on magnetic resonance imaging, resolution of severe stenosis of the internal carotid artery, and normalization of swollen pituitary tissues. Two of 3 cases fulfilled the histological criteria of immunoglobulin G4-related disease, although none of the patients had high serum immunoglobulin G4 level. CONCLUSION: The true implications of such unusual spreading of hypophysitis to nearby organs are not fully understood, but the mechanism of occurrence might vary according to the timing of inflammation in this unusual mode of spreading. Pulse dose steroid therapy achieved remarkably good outcomes even in the patient with progressive severe stenosis of the internal carotid artery and rapid visual deterioration.

Metachronous, multicentric glioma of pilocytic astrocytoma with oligodendroglioma-like component and oligodendroglioma through distinct genetic aberrations.

This patient presented with a rare case of metachronous, multicentric gliomas first manifesting as headache and nausea in 1983 when he was an 8-year-old boy. Computed tomography revealed a cerebellar tumor and the tumor was subtotally resected. The histological diagnosis was pilocytic astrocytoma, and radiation therapy to the posterior fossa and chemotherapy consisting of nimustine hydrochloride and fluorouracil were performed. In 1989, at age 14 years, the patient presented with local recurrence. He underwent gross-total resection of the tumor, and histological examination revealed that the tumor consisted of classic pilocytic astrocytoma with a biphasic pattern and a small oligodendroglioma-like component. In 2011, at age 36 years, he presented with seizure. Magnetic resonance imaging revealed a mass lesion in the right middle frontal gyrus. Gross-total resection of the tumor was performed, and the histological diagnosis was oligodendroglioma. Genetic analyses revealed amplification of the BRAF gene in both the primary cerebellar pilocytic astrocytoma and the recurrent tumor with biphasic features, as well as a BRAF V600E missense mutation in the oligodendroglioma-like component. On the other hand, the IDH1 R132H mutation, instead of aberrations of the BRAF gene, was identified in the oligodendroglioma arising in the right frontal lobe. Different types of aberrations of the BRAF gene in the classic and oligodendroglioma-like component in the recurrent pilocytic astrocytoma suggest that they had different cell origins or that amplification of BRAF was negatively selected under the de novo BRAF V600E mutation. In addition, the aberration profiles of IDH1 and BRAF suggest that the oligodendroglioma arose independent of cerebellar pilocytic astrocytoma.

[Case report of lumbar discal cyst].

The authors describe a rare case of lumbar discal cyst which produced manifestations similar o lumbar disc herniation. A 33-year-old man, who had had a crick in the back 3 months previously, suffered from severe low back and right lower-extremity pain. The neurological examination showed the L5 radiculopathy through the positive straight leg-raising test, no motor weakness nor sensory disturbance with normal reflexes. Magnetic resonance imaging demonstrated an oval shaped extradural lesion with a low signal intensity on T1-weighted images and a high signal intensity on T2-weighted images. Additionally, the surrounding rim of the cyst was enhanced with the addition of Gd-DTPA. As we diagnosed a lumbar discal cyst with severe symptoms, the patient received emergent surgery. The symptom disappeared immediately after surgery. This case implies that early surgery for discal cyst may be an effective means to obtain release from symptoms.