Takachika Aoki

Primary amebic meningoencephalitis due to Naegleria fowleri: An autopsy case in Japan

Free‐living amebas represented by Naegleria fowleri, Acanthamoeba and Balamutia have been known to cause fatal meningoencephalitis since Fowler and Carter (1965) reported the first four human cases. An autopsy case of a 25‐year‐old female with primary amebic meningoencephalitis (PAM) due to Naegleria fowleri is described. Headache, lethargy and coma developed in this patient, and her condition progressed to death 8 days after the onset of clinical symptoms. Cerebral spinal fluid examination confirmed clusters of amebas, which were grown in culture and identified as Naegleria fowleri. At autopsy, lesions were seen in the central nervous system (CNS) and the ethmoid sinus. The CNS had severe, suppurative meningoencephalitis with amebic trophozoites mingled with macrophages. This case is the first report of PAM due to Naegleria fowleri in Japan.

Leakage Sign for Primary Intracerebral Hemorrhage A Novel Predictor of Hematoma Growth

Background and Purpose— Recent studies of intracerebral hemorrhage treatments have highlighted the need to identify reliable predictors of hematoma expansion. Several studies have suggested that the spot sign on computed tomographic angiography (CTA) is a sensitive radiological predictor of hematoma expansion in the acute phase. However, the spot sign has low sensitivity for hematoma expansion. In this study, we evaluated the usefulness of a novel predictive method, called the leakage sign. Methods— We performed CTA for 80 consecutive patients presenting with spontaneous intracerebral hemorrhage. Two scans were completed: CTA phase and delayed phase (5 minutes after the CTA phase). By comparing the CTA phase images, we set a region of interest with a 10-mm diameter and calculated the Hounsfield units. We defined a positive leakage sign as a >10% increase in Hounsfield units in the region of interest. Additionally, hematoma expansion was determined on plain computed tomography at 24 hours in patients who did not undergo emergent surgery. Results— Positive spot signs and leakage signs were present in 18 (22%) patients and 35 (43%) patients, respectively. The leakage sign had higher sensitivity (93.3%) and specificity (88.9%) for hematoma expansion than the spot sign. The leakage sign, but not the spot sign, was significantly related with poor outcomes (severely disabled, vegetative state, and death) in all of the patients (P=0.03) and in patients with a hemorrhage in the putamen (P=0.0016). Conclusions— The results indicate that the leakage sign is a useful and sensitive method to predict hematoma expansion.

Sequential pathological changes during malignant transformation of a craniopharyngioma: A case report and review of the literature

Background: Malignant transformation of craniopharyngiomas is quite rare, and the etiology of transformation remains unclear. The prognosis of malignantly transformed craniopharyngiomas is very poor. Case Description: A 36-year-old male had five craniotomies, five transsphenoidal surgeries, and two radiation treatments until 31 years of age after diagnosis of craniopharyngioma at 12 years of age. All serial pathological findings indicated adamantinomatous craniopharyngioma including those of a surgery performed for tumor regrowth at 31 years of age. However, when the tumor recurred approximately 5 years later, the pathological findings showed squamous metaplasia. The patient received CyberKnife surgery, but the tumor rapidly regrew within 4 months. The tumor was resected with the cavernous sinus via a dual approach: Transcranial and transsphenoidal surgery with an extracranial-intracranial bypass using the radial artery. Pathologic examination of a surgical specimen showed that it consisted primarily of squamous cells; the lamina propria was collapsed, and the tumor cells had enlarged nuclei and clarification of the nucleolus. The tumor was ultimately diagnosed as malignant transformation of craniopharyngioma. After surgery, he received combination chemotherapy (docetaxel, cisplatin, and fluorouracil). The tumor has been well controlled for more than 12 months. Conclusion: Serial pathological changes of the craniopharyngioma and a review of the 20 cases reported in the literature suggest that radiation of the squamous epithelial cell component of the craniopharyngioma led to malignant transformation via squamous metaplasia. We recommend aggressive surgical removal of craniopharyngiomas and avoidance of radiotherapy if possible.

Angiomatous variant of pleomorphic xanthoastrocytoma in a patient with a 20‐year history of epilepsy

The angiomatous variant of the pleomorphic xantho‐astrocytoma (PXA) is a morphological subtype of PXA that is characterized by the presence of large numbers of tiny blood vessels with variable wall thicknesses. A case of an angiomatous variant of PXA occurring in the temporal lobe of a 43‐year‐old man is presented. The patient had a 20‐year history of seizures. Considering the clinical course and intra‐operative electro‐encephalography findings, it appears that this tumor was the epileptic focus in this patient and that it had been present for 20 years. Histopathologically, various degenerative changes, such as microcystic changes, calcification and hyaline thickening of vessel walls were seen in the tumor. In particular, obvious vascularity in the tumor and secondary vascular degenera‐tion should be related to gradual growth and benign clinical course of an angiomatous variant of PXA.

Long-term Prognosis after Extracranial-intracranial Bypass Surgery for Symptomatic Cerebrovascular Occlusive Disease

Prognosis after extracranial-intracranial (EC-IC) bypass surgery has only been studied for a few years and the benefits of this procedure are still controversial. In this single-center retrospective study, we examined the long-term prognosis of patients who underwent EC-IC bypass surgery. Subjects were patients with symptomatic internal carotid artery or intracranial lesion occlusive disease who underwent EC-IC bypass surgery between 1991 and 2003. Of these, long-term prognosis was examined in 57 patients (39 male, 18 female; mean age, 61.8 years) who showed good surgical outcomes 30 days after bypass surgery, measured as a 0-2 on the modified Rankin Scale (mRS). They were divided into 2 groups (survivors and non-survivors) and were analyzed to identify factors effecting long-term survival after bypass surgery. Sixteen patients (28%), whose mean follow-up period (survival time) was 8.3±3.8 years, died after the bypass surgery. The average follow-up period for the survivors was 12.0±1.1 years, which was significantly longer than that for the non-survivors (P<0.0001). At surgery, the non-survivors (mean age 71.5 years) were significantly older than the survivors (P=0.0012). Pneumonia and other respiratory diseases were a frequent cause of death (31.2%), but death by cerebrovascular disease also occurred (12.5%). The rate of recurrent ischemic stroke was 28%, with no significant difference between groups (survivors vs. non-survivors: 31.2% vs. 26.1%, P= 0.82). In the absence of perioperative complications, the long-term prognosis of patients who underwent EC-IC bypass surgery was very good.

Comparative outcome analysis of anterior choroidal artery aneurysms treated with endovascular coiling or surgical clipping

Background: Treatment of anterior choroidal artery (AChA) aneurysms with endovascular coiling or surgical clipping may increase the risk of ischemic complications owing to the critical territory supplied by the AChA. We analyzed the surgical results of endovascular coiling and surgical clipping for AChA aneurysms performed in a single institution, as well as the role of indocyanine green-videoangiography (ICG-VAG) and motor-evoked potential (MEP). Methods: We analyzed 50 patients (51 aneurysms; 21 men, 29 women; mean age: 58 years) including 25 with subarachnoid hemorrhage treated with endovascular coiling or surgical clipping between April 1990 and October 2013. The complication rates and clinical outcomes of the coil group (mean follow-up: 61 months) and the clip group (mean follow-up: 121 months) were analyzed with a modified Rankin scale. Results: The overall clinical outcome of the coil group (95%) was better than that of the clip group (85%). Especially, the outcomes in the coil group were better in the first investigated period (1990–2007) (P < 0.05). However, after the introduction of ICG-VAG and MEP, the outcomes in the clip group improved significantly (P = 0.005), and treatment-related complications decreased from 20 to 4.7%. Eleven aneurysms (coil group: 8, clip group: 3) showed small neck remnants but no remarkable regrowth, except for 1 case during the mean follow-up period of 91 months. Conclusions: Surgical clipping of AChA aneurysms has become safer because of ICG-VAG and MEP monitoring. Coiling and clipping of AChA aneurysms showed good and comparable outcomes with these monitoring methods.

Nontraumatic aneurysm rupture following an endoscopic third ventriculostomy and ventricular drainage: Case report of a rare complication

Background: Although endoscopic third ventriculostomy is a safe procedure, the authors report a case of aneurysmal subarachnoid hemorrhage as an unusual and serious complication of an endoscopic third ventriculostomy and ventricular drainage. Case Description: A 60-year-old male presented with obstructive hydrocephalus caused by midbrain tumors was admitted to our hospital. Endoscopic third ventriculostomy and external ventricular drainage were successfully performed. Two days after the operation, he became comatose, and a computed tomography (CT) scan revealed a diffuse subarachnoid hemorrhage. Emergency cerebral angiogram showed an aneurysm of the left internal carotid artery. Endovascular coil embolization of the ruptured aneurysm was then performed. Conclusion: The rupture of the aneurysm may have been induced by excessive cerebrospinal fluid drainage after the endoscopic third ventriculostomy. Planning for intracranial endoscopic procedures should consider that rupture of an unknown previously unruptured aneurysm is a possible complication.

Novel Indirect Revascularization Technique with Preservation of Temporal Muscle Function for Moyamoya Disease Encephalo-Duro-Fascio-Arterio-Pericranial-Synangiosis: A Case Series and Technical Note

BACKGROUND Direct and/or indirect bypass surgery is the established approach for preventing stroke in patients with moyamoya disease. However, conventional indirect revascularization, including encephalo-myo-synangiosis, has some disadvantages associated with the mass effect of the temporal muscle under the bone flap and postsurgical depression in the temporal region. We devised a novel indirect revascularization method, using only the temporal fascia, to address the aforementioned disadvantages. METHODS A skin incision was performed along the superficial temporal artery. The temporal fascia was cut such that the base of the fascia flap was on the posterior side. The fascia and temporal muscles were dissected separately. After turning over the fascia, the muscle was cut such that the base of the muscle flap was on the anterior side. Craniotomy, direct bypass, and encephalo-duro-synangiosis were performed conventionally. Only the temporal fascia was used for indirect revascularization and duraplasty. The muscle was replaced in the anatomically correct position after replacing the bone flap. RESULTS We performed the aforementioned surgery on 18 (13 women and 5 men) consecutive patients (21 cerebral hemispheres) enrolled between 2012 and 2016. The average age was 28.7 years. The mean follow-up period was 31.6 months. In 17 patients (94%), the symptoms and cerebral blood flow improved. Digital subtraction angiography showed satisfactory angiogenesis from the temporal fascia. Depression in the temporal region and atrophy of the temporal muscle were negligible. CONCLUSIONS This surgical technique provides good clinical and cosmetic outcomes. It may also be one of the good surgical treatments available for symptomatic moyamoya disease.

Stenotic changes of the posterior cerebral artery are a major contributing factor for cerebral infarction in moyamoya disease

Background: Some patients with moyamoya disease (MMD) show broad infarction with moderate internal carotid artery (ICA) stenosis, whereas others with complete ICA occlusion show no infarction. This suggests that other factors contribute to the occurrence of infarction. Contributing factors predictive of cerebral infarcts must be identified for the prevention of infarction and the consequent neurological deficits. Methods: We examined data from 93 patients with confirmed MMD for the presence of infarction (n = 72), transient ischemic attack (TIA, n = 41), asymptomatic presentation (n = 51), or hemorrhage (n = 22) in 186 bilateral cerebral hemispheres. We analyzed the relationship between the occurrence of infarction and several clinical factors, such as steno-occlusive status or the site of the ICA and posterior cerebral artery (PCA). Results: The incidence of PCA steno-occlusive lesions was significantly higher in infarcted (77.8%) than in non-infarcted hemispheres (TIA, 14.6%; asymptomatic, 9.8%; hemorrhagic 9.1%; P < 0.01). The steno-occlusive site of ICA was also a significant factor (P < 0.05). There was no significant correlation between the occurrence of infarction and the steno-occlusive status of the ICA or grade of the moyamoya vessels. Multivariate statistical analysis demonstrated that the PCA steno-occlusive changes were an important contributing factor for infarction (P < 0.0001). Conclusions: This is the multivariate statistical analysis study identifying PCA steno-occlusive lesions as the most important independent factor that is predictive to cerebral infarction in moyamoya patients. The prediction and inhibition of PCA steno-occlusive changes may help to prevent cerebral infarction.

Unusual hemodynamic stroke related to an accessory middle cerebral artery: The usefulness of fusion images from three-dimensional angiography

Background: Ischemic stroke associated with an anomaly of the middle cerebral artery (MCA) is a rare occurrence. The diagnosis is very difficult when there are steno-occlusive lesions associated with an accessory middle cerebral artery (AMCA). Case Description: A 77-year-old female with hypertension and hyperlipidemia experienced repeated transient ischemic attacks (TIAs) of motor aphasia and dysarthria. Although angiography showed only left intracranial occlusion, the fusion images of three-dimensional digital subtraction angiography (3-D DSA) showed complex steno-occlusive lesions and an AMCA related with the TIA. The cerebral blood flow (CBF) to the left frontal lobe was supplied by the AMCA, via the anterior communicating artery from the right internal carotid artery. The left temporal and parietal lobes were supplied by the stenotic MCA, via the left posterior communicating artery from the left posterior cerebral artery. Single-photon emission computed tomography showed a marked decrease in CBF to both the left frontal and temporal lobes. A left superficial temporal artery (STA)-to-left MCA double anastomosis was performed, in which each branch of the STA supplied branches of the AMCA and MCA. Conclusion: This is the first reported case of ischemic stroke in a patient with an AMCA. The exact diagnosis could be made only by using fusion images of 3-D DSA, which were useful for understanding the complicated CBF pattern and for the choice of recipient artery in bypass surgery.