Nobuhiro Nakagawa

Early effects of boron neutron capture therapy on rat glioma models

Early effects of boron neutron capture therapy (BNCT) on malignant glioma are characterized by reduction of the enhancement area and regression of the peritumoral edema radiologically. The aim of this study was to investigate the early histological changes of tumors and inflammatory cells after BNCT in the rat brain. Rats were treated with BNCT using boronophenylalanine (BPA) 7 days after implantation of C6 glioma cells. The tumors were assessed with magnetic resonance imaging and histopathological examination at 4 days after BNCT. The mean tumor volumes were 39 ± 2 mm3 in the BNCT group and 134 ± 18 mm3 in the control group. In the BNCT group, tumor cells showed a less pleomorphic appearance with atypical nuclei and mitotic figures. The Ki-67 labeling index was 6.5% ± 4.7% in the BNCT and 35% ± 3.8% in the control group. The reactions of the inflammatory cells were examined with ED-1 as macrophage marker and OX42 as microglia marker. ED-1- and OX-42-positive cells were reduced both in the core and the marginal area of the tumor in the BNCT group. It is suggested that BNCT reduced tumor progression by suppression of proliferation. Inhibition of the activated macrophages may relate to reduced peritumoral edema in the early phase.

A novel technique for identifying the fistulous point in a direct carotid-cavernous fistula

The fistulous point in a direct carotid-cavernous fistula (CCF) can often be difficult to identify because of high-flow shunting. A novel technique that is useful for identifying the fistulous point is reported. A 71-year-old woman underwent endovascular therapy for a left direct CCF that presented with sudden diplopia and tinnitus. To identify the fistulous point, vertebral angiography with manual compression of the left carotid artery was attempted, as was slow injection of a contrast agent from a balloon guiding catheter, closing off the left internal carotid artery; however, the shunt flow was very rapid, and identification was not possible. Therefore, three-dimensional digital subtraction angiography of the vertebral artery was performed while also performing manual aspiration from the balloon guiding catheter, closing off the left internal carotid artery. This reduced early visualization of the cavernous sinus and enabled an aneurysm in the cavernous sinus to be clearly visualized. Embolization was performed transarterially and transvenously, and the shunt flow disappeared completely. Vertebral angiography combined with manual aspiration from a balloon guiding catheter closing off the internal carotid artery is useful for identifying the fistulous point in a direct CCF.

Endovascular Microcatheter Provocation Test for the Diagnosis of Glossopharyngeal Neuralgia

OBJECTIVE Glossopharyngeal neuralgia (GN) is a rare disease often clinically misdiagnosed as trigeminal neuralgia. An endovascular provocative test has been applied to assist in making the diagnosis of GN caused by vascular compression. We similarly used endovascular provocative techniques to identify the causative vessel and to evaluate the indication for microvascular decompression (MVD) in two patients. METHODS Two patients had severe retroauricular and pharyngeal pain that could not be controlled by medical therapy. Magnetic resonance imaging and magnetic resonance angiography showed a high-riding right posterior inferior cerebellar artery (PICA). We decided to apply the endovascular provocation test to prove the assumed GN and identify potential indications for MVD. RESULT A loop of the PICA appeared to compress the glossopharyngeal nerve in the first patient. In this patient, a microcatheter was inserted into the right PICA, decreasing the GN. The patient underwent MVD, resulting in complete pain relief. In the second patient, a microcatheter was inserted into the right PICA, and an attack of typical GN occurred, with pain in the posterior region of the tongue, tonsils, oropharynx, and larynx. The patients severe pain was clearly different from this typical GN caused by the microcatheter provocation test, and MVD was not performed. CONCLUSION The diagnosis of GN is sometimes complex. The endovascular provocative technique may allow identification of GN caused by vascular compression.

Urgent Carotid Artery Stenting for Carotid-Related Stroke-in-Evolution

BACKGROUND Stroke-in-evolution (SIE) is a major outcome determinant in patients with acute ischemic stroke. The benefit of surgery for treatment of carotid artery-related SIE remains controversial. OBJECTIVE To retrospectively evaluate the use of carotid artery stenting (CAS) as a possible alternative treatment in patients with carotid-related SIE. METHODS Ten patients with carotid-related SIE were treated with CAS from May 2005 to December 2014. The mean initial National Institutes of Health Stroke Scale (NIHSS) score was 5.4 ± 4.4. Two patients had total occlusion of the internal carotid artery, and 8 had severe stenosis. The mean interval from symptom onset to clinical deterioration was 2.9 ± 2.9 d. The mean NIHSS score after deterioration was 14.3 ± 4.5. In the hemodynamic assessment using perfusion imaging, the ipsilateral cerebral hemodynamics was impaired in 7 of 8 patients. RESULTS All patients underwent urgent CAS in the acute phase of SIE. Seven patients underwent CAS using flow reversal with or without distal protection. No procedure-related complications occurred in any patients, although 1 patient developed aspiration pneumonia. The mean NIHSS score 7 d after CAS was 4.8 ± 2.3. Six patients (60%) had a modified Rankin scale score of 0 to 2 at discharge. CONCLUSION Urgent CAS for carotid-related SIE with hemodynamic impairment appears to be an effective method for achieving good clinical outcomes.

Seizures and Tumor Progression in Glioma Patients with Uncontrollable Epilepsy Treated with Perampanel

Background/Aim: Excessive extracellular glutamate activates AMPA-type glutamate receptors (AMPA receptors) and induces seizures. Antagonistic activation of AMPA receptors inhibits epilepsy and glioma growth in in vitro and in vivo studies. This study was conducted to evaluate the clinical impacts of perampanel (PER), a novel AMPA receptor antagonist, on seizures and tumor progression in glioma patients with uncontrollable epilepsy. Patients and Methods: Twelve glioma patients with uncontrollable epilepsy were treated with PER. Seizure response, PER concentration, and tumor volume were assessed. Results: Obvious seizure control was observed in 10 analyzed patients (100%) and 6 patients (60%) became seizure-free. Median plasma concentrations of PER were 296 ng/ml in those with 4 mg/day PER treatment and 518 ng/ml in those with 8 mg/day PER treatment. High-intensity lesions in fluid-attenuated inversion recovery of magnetic resonance imaging (MRI) were volumetrically assessed to analyze tumor size. Volume reduction was detected within 6 months in correlation with increased plasma levels of PER. Conclusion: PER treatment was effective in uncontrollable epilepsy with gliomas. MRI images showed the inhibition of tumor growth.

Transfemoral Stenting of Stenoses at the Common Carotid Artery Origin Using an Anchoring Technique With a Balloon Protection Device.

BACKGROUND Transfemoral stenting of stenoses at the common carotid artery (CCA) origin is technically difficult because of poor stability of the guiding catheter. OBJECTIVE To describe an anchoring technique using a balloon protection device that provides excellent stability of the guiding catheter. METHODS Four patients (5 stenotic lesions) with stenosis of the CCA origin underwent transfemoral stenting with a balloon protection device (PercuSurge GuardWire; Medtronic, Santa Rosa, California). These 5 stenotic lesions of the CCA origin included 1 on the right side and 4 on the left side. Two of the stenoses were symptomatic, and 3 were asymptomatic. A balloon-expandable stent (Express LD stent; Boston Scientific, Natick, Massachusetts) was used in all patients. RESULTS All stenoses were successfully dilated. With the balloon protection device as an anchor in all patients, the guiding catheter was highly stable during the procedure. There were no intraprocedural or periprocedural ischemic complications in any patients. None of the patients developed a stroke during a mean follow-up period of 8.4 months. CONCLUSION The anchoring technique using a balloon protection device is useful for transfemoral stenting of stenoses at the CCA origin. ABBREVIATIONS CCA, common carotid arteryECA, external carotid arteryICA, internal carotid arteryPTA, percutaneous transluminal angioplasty.

Spontaneous Closure of a Dural Arteriovenous Fistula Immediately after Cerebral Angiography Using a Gadolinium Contrast Agent

Gadolinium (Gd) contrast agents have been used instead of iodinated contrast agents in patients in whom iodine is contraindicated, but cerebral angiography of a dural arteriovenous fistula (dAVF) using a Gd contrast agent has not previously been reported. We recently performed cerebral angiography using a Gd contrast agent in a patient with an anterior condylar confluence dAVF who was allergic to iodine. To our surprise, there was spontaneous closure of the dAVF immediately after angiography. We now report what we believe is the first such case report.