Keiji Kidoguchi

Cerebral Vasoreactivity and Internal Carotid Artery Flow Help to Identify Patients at Risk for Hyperperfusion After Carotid Endarterectomy

Background and Purpose— Hyperperfusion syndrome is a rare but potentially devastating complication after carotid endarterectomy (CEA). The aim of this study was to investigate whether preoperative measurement of cerebral vasoreactivity (CVR) and intraoperative measurement of internal carotid artery (ICA) flow could identify patients at risk for hyperperfusion after CEA. Methods— For 26 patients with unilateral ICA stenosis ≥70%, cerebral blood flow (CBF) and CVR were investigated before and 1 month after CEA, with resting and acetazolamide-challenge single-photon emission CT. CBF on the first postoperative day was also measured. ICA flow was measured before and after reconstruction by electromagnetic flowmeter during surgery. Results— Ipsilateral CBF on the first postoperative day significantly increased relatively (56.6±53.2%) as well as absolutely (37.9±8.8 to 57.7±18.0 mL/100 g per minute) in the reduced CVR group (CVR <12%) but not in the normal CVR group (CVR ≥12%) (10.3±15.5% and 40.6±7.9 to 43.9±5.7 mL/100 g per minute, respectively). One month later, this difference almost disappeared. Two patients showed ipsilateral CBF increase of ≥100%. A significant association of intracerebral steal with hyperperfusion (CBF increase ≥100%) on the first postoperative day was also observed. ICA flow increase after reconstruction significantly correlated with CBF increase on the first postoperative day in the reduced CVR group but not in the normal CVR group. The threshold of ICA flow increase for hyperperfusion was estimated to be 330 mL/min in the reduced CVR group. Conclusions— Single-photon emission CT with acetazolamide challenge and ICA flow measurement during surgery could identify patients at risk for hyperperfusion after CEA, in whom careful monitoring and control of blood pressure should be initiated even intraoperatively.

In Vivo X-Ray Angiography in the Mouse Brain Using Synchrotron Radiation

Background and Purpose— We, for the first time, performed in vivo x-ray angiography in the mouse brain using SPring-8, a third-generation synchrotron radiation facility. Methods— A thin PE-50 tube was placed in the unilateral external carotid artery in adult male C57BL/6J mice. While maintaining the blood flow in the internal carotid artery, 33 &mgr;L of contrast agent was injected and then selective angiography of the hemisphere was performed. Results— The average diameters of cerebral artery were as follows: 142.5±7.90 &mgr;m in middle cerebral artery, 138.3±9.35 &mgr;m in anterior cerebral artery, 120.5±5.53 &mgr;m in posterior cerebral artery, and 162.6±10.87 &mgr;m in internal carotid artery (n=5). To demonstrate the changes in diameter, we induced hypercapnia and detected the dilatation of the vessels between 121% and 124% of the original diameters (n=5). We also repeated angiography in the mice before and after intracarotid injection of vasodilatation drugs papaverine hydrochloride, ATP disodium, and fasudil hydrochloride hydrate and demonstrated the chronological changes in the diameters in each artery at 1, 5, 15, and 30 minutes after injection (n=1 for each drug). Conclusions— Using only a minimum volume of the contrast agent, synchrotron radiation enables us to study x-ray angiography in the mouse brain. The morphology of the vessels can be clearly observed under physiological conditions. The diameters and their changes can also be successfully studied in vivo.

Diagnostic yield and morbidity by neuronavigation-guided frameless stereotactic biopsy using magnetic resonance imaging and by frame-based computed tomography-guided stereotactic biopsy.

Background: We compared the diagnostic yield and morbidity by frame-based computed tomography-guided stereotactic biopsy (CTSTB) with Brown-Roberts-Wells (BRW) unit and by neuronavigation-guided frameless stereotactic biopsy (NSTB) using magnetic resonance imaging (MRI). Methods: The subjects’ age range was 15-83 years. CTSTB with BRW unit was performed for 59 tumors (58 cases, 1988-2007). NSTB was performed for 38 tumors (35 cases, 2007-2013) with the needle sheath attached to the head holder. By NSTB, target locations of sampling points and trajectories were confirmed by using MRI. Diffusion tensor imaging-based fiber tractography was used to achieve safe trajectories. STB by using BRW did not visualize the trajectory virtually; however, the planning images for NSTB were able to show the trajectory virtually before the procedure. Results: Histological diagnoses were established for 93 tumors at the first biopsy. The diagnostic yield was 94.9% by CTSTB and 97.4% by NSTB (P = 0.944). The morbidity rate was 5.1% by CTSTB and 0% by NSTB (P = 0.417). The absolute risk reduction was 23.1% by NSTB when the targets were basal ganglia (putamen, globus pallidus) or thalamus. In the cases of glioma for which the targets were basal ganglia (putamen, globus pallidus) or thalamus, the absolute risk reduction by NSTB was 30%. Conclusions: There was no significant difference between CTSTB and NSTB concerning the diagnostic yield and morbidity. However, when the target is the basal ganglia (putamen, globus pallidus) or thalamus and glioma is suspected, NSTB by using MRI with virtual trajectory is preferable to CTSTB concerning morbidity.

In Vivo Cerebral Artery Microangiography in Rat and Mouse Using Synchrotron Radiation Imaging System

Microangiography with spatial resolution in the micrometer range was carried out to depict vascular responses of the cerebral artery and arterioles in rats and mice using a real-time imaging system and a third generation synchrotron radiation source at SPring-8. An X-ray direct-conversion type detector with 6-mum spatial resolution was developed for real-time biomedical imaging. The X-ray image is converted directly into an electrical signal in the photoconductive layer without image blurring. In synchrotron radiation radiography, a long source-to-object distance and a small source spot can produce high-resolution images. Microangiographic images were obtained without image blurring and were stored in a digital frame memory system with a 1024 x 1024-pixel, 10-bit format. In imaging experiments, vasoconstriction and vasodilatation of small cerebral arteries were visualized in response to hypercapnia, hemorrhagic hypotension, and vasoactive agents after iodine contrast agent injection into the carotid artery.

Skull metastasis as initial manifestation of pulmonary epithelial-myoepithelial carcinoma: a case report of an unusual case.

Epithelial-myoepithelial carcinoma (EMC) of the lung is rare and is considered to be low-grade malignancy. Intracranial metastasis of pulmonary EMC has not previously been reported according to our search of the literature. We report a case of skull metastasis as the initial manifestation of pulmonary EMC. An 81-year-old man complained of left leg motor weakness. Neurological examination showed left hemiparesis. Computed tomography and magnetic resonance imaging revealed an osteolytic tumor in the right frontal bone with invasion to the dura and subdural space, attached to the superior sagittal sinus. Subtotal removal of the tumor was performed, and the left hemiparesis showed improvement. Histopathological study revealed the tumor to consist of epithelial and myoepithelial cells. Pulmonary EMC was diagnosed. The MIB-1 index in primary lesion was approximately 10%. The skull and dura are possible sites for metastasis from pulmonary EMC. The MIB-1 index is a predictive marker of malignant potential.

Strategy for patients with co-existence of meningioma and intracerebral aneurysm, especially unruptured aneurysm (–seven cases and review of the literature–)

BACKGROUND Intracerebral aneurysms co-existing with meningiomas are rare. Treatment strategies for intracerebral aneurysms co-existing with meningiomas have not yet been established. METHODS We studied 62 patients with intracerebral aneurysms co-existing with meningiomas in the literature including our seven cases, evaluated the various managements and outcomes, and discussed the strategy for intracerebral aneurysms, especially unruptured cases, co-existing with meningiomas. The aim of this study was to develop a guide for the management of non-subarachnoid hemorrhage (SAH) intracerebral aneurysms co-existing with meningiomas. RESULTS Most intracerebral aneurysms co-existing with meningiomas are unruptured. Of course, aneurysms presenting with SAH should be treated first followed by the resection of meningiomas. In addition, intracerebral aneurysms inside or adjacent to meningiomas have a high risk of intraoperative rupture during the surgery for meningiomas, and it may be necessary to treat them first followed by the resection of meningiomas with one or two-step surgery. In nine out of 62 patients, ten intracerebral unruptured aneurysms were not treated; however, no intracerebral aneurysms ruptured during the follow-up period, and outcomes of these patients were good in eight and poor in only one. CONCLUSIONS Intracerebral unruptured aneurysms remote from meningiomas may be treated according to the guidelines for unruptured aneurysms. In advance of microsurgery and endovascular techniques, both lesions should be treated, if possible.

Supratentorial extraventricular WHO grade III (anaplastic) ependymoma 17 years after total removal of WHO grade II ependymoma of the fourth ventricle

Abstract We report a WHO grade III ependymoma of the supratentorial interhemispheric fissure and grew to form a large mass with anaplastic transformation without local recurrence 17 years after the total removal of a fourth ventricular WHO grade II ependymoma. We emphasize the necessity of long-term follow-up, even in benign ependymomas.