Yoshitaka Okada

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The craniovertebral junction is clinically important. The vertebral artery (VA) in its several variations runs within this area. We report the prevalence of these VA variations on magnetic resonance angiography (MRA). We retrospectively reviewed MRA images, obtained using two 1.5-T imagers, of 2,739 patients, and paid special attention to the course and(More)
We introduce an anatomical and electrophysiological model of deep brain structures dedicated to magnetoencephalography (MEG) and electroencephalography (EEG) source imaging. So far, most imaging inverse models considered that MEG/EEG surface signals were predominantly produced by cortical, hence superficial, neural currents. Here we question whether crucial(More)
A persistent trigeminal artery (PTA) is the most common carotid-vertebrobasilar anastomosis. A cerebellar artery that arises from the precavernous segment of the internal carotid artery (ICA) without connecting to the basilar artery is regarded as a PTA variant. Our study aimed to determine the incidence of PTA and its variants and classify them based on(More)
Fenestrations of cerebral arteries are most common in the vertebrobasilar (VB) system, and magnetic resonance (MR) angiographic studies of these variations are sparse. We retrospectively reviewed MR angiographic images of 3,327 patients; images were obtained using two 1.5-T imagers and picked up fenestrations of the intracranial vertebral artery (VA), VB(More)
Duplicate origin of the middle cerebral artery (MCA) is rare and has been misdiagnosed or confused as fenestration of the proximal M1 segment of the MCA. The condition is not a true fenestration and occurs when two MCA branches arise separately from the terminal segment of the internal carotid artery, and fuse to form an arterial ring. We researched our(More)
PURPOSE To examine the incidence and appearance of the communicating vein between the left renal vein (LRV) and the left ascending lumbar vein (LALV) on abdominal CT. MATERIALS AND METHODS We reviewed the appearance of the communicating vein on contrast-enhanced CT obtained by multidetector-row CT (MDCT) scanner. One hundred patients without known(More)
Persistent hypoglossal artery (PHA) is the second most common anastomosis between the carotid and vertebrobasilar systems and demonstrates some variations. We evaluated the prevalence of PHA on computed tomography (CT) angiography. We also evaluated characteristic features of PHA and its variants on magnetic resonance (MR) angiography. We retrospectively(More)
It is well known that the occipital artery (OA) can arise from the internal carotid artery (ICA) or vertebral artery (VA). However, the incidence of an anomalously originating OA has not been reported. We investigate its incidence and characteristic features on magnetic resonance angiography (MRA). We retrospectively reviewed MRA images of 2,866 patients(More)
An 85-year-old woman was referred to the medical oncology department because of a hypogastric mass. Contrast-enhanced CT showed a large hypervascular mass in the lower abdomen. CT angiography with volume rendering imaging revealed a vascular pedicle with an arborizing pattern of vessels. Many thick, early draining veins shunting into the portal vein were(More)
The origin of the vertebral artery (VA) varies, though most VAs enter the transverse foramen (TF) of the sixth cervical vertebra. On computed tomography (CT) angiographic images, we evaluated the prevalence of variations of both VA origin and its level of entry into the TF. We retrospectively reviewed CT angiographic images of 2,287 patients obtained using(More)