Akio Fukusumi

Age correlation of the time lag in signal change on EPI-fMRI

PURPOSE We measured the time lags between the start or end of tasks and signal changes in functional MRI (fMRI) for various age groups and evaluated the age correlation of the time lags. METHODS Forty subjects, 20-76 years old, were evaluated. fMRI was performed with and echo planar imaging sequence at 0.5 s intervals. We measured the time for the signal of the precentral gyrus to make a half-maximal increase after starting the task (T-inc) and the time to reach the initial level after ceasing the task (T-dec). RESULTS Average T-inc was 3.09 s and T-dec was 6.63 s. The values of T-inc could be correlated to age. T-dec had no age correlation. CONCLUSION The time lag in fMRI was revealed to be prolonged with increasing age. Our results suggest that the time lag in fMRI is influenced by some factors associated with aging.

Micro‐angiographical studies of the medullary venous system of the cerebral hemisphere

In order to identify the zones of convergence of the medullary veins of the cerebral white matter, gelatin‐mixed barium sulfate was injected into normal brains at autopsy. A catheter was inserted into the internal jugular veins or the carotid and vertebral arteries. Serial soft tissue roentgenograms of whole brains and brain slices were used to determine the zones of convergence. The deep med‐ullary veins had four zones of covergence before draining into the subependymal veins: the first (superficial), second (candelabra), third (palmate) and fourth (subependymal). The zones of various convergence within the white matter were due to the crossing of nerve fiber tracts (e.g. the pes of the corona radiata, the radiation of the corpus callosum, the superior occipitofrontal fasciculus, the tapetum and the sagittal strata). Similar but less conspicuous information about the parenchymal arteries was observed in the arterial injection studies. These results suggest that micro‐angiographical studies of the medullary veins of the cerebral white matter provide detailed information on veno‐architecture and convergence zones. This information may help in understanding the pathogenesis of medullary venous malformations.

Usefulness of contrast-enhanced magnetic resonance angiography for follow-up of coil embolization with the enterprise stent for cerebral aneurysms.

Objective: The aim of this study was to determine the feasibility and usefulness of contrast-enhanced magnetic resonance angiography (CE-MRA) and 3-dimensional (3D) time-of-flight (TOF) MRA for follow-up of intracranial aneurysms treated using the Enterprise stent. Methods: Five aneurysm cases using the Enterprise stent were prospectively analyzed and were followed up with CE-MRA, 3D TOF MRA, and digital subtraction angiography (DSA). Depictions of parent artery lumen and the aneurysm neck with 3D TOF MRA and CE-MRA were compared with those of DSA. Results: In all cases, on 3D TOF MRA, it was difficult to evaluate the parent artery lumen and aneurysm neck owing to the significant artifacts from the stent. Contrast-enhanced MRA sufficiently demonstrated parent artery lumen and aneurysm neck distinctly and as clear as DSA did in all cases. Conclusions: For follow-up after coiling with an Enterprise stent, CE-MRA may be necessary to avoid susceptibility artifacts caused by the stent.

Initial experience of using the filter protection device during carotid artery stenting in Japan

Purpose No filter protection devices for carotid artery stenting (CAS) have been formally approved for use in Japan; however, as of April 2008, the Angioguard XP (AGXP) was approved. This article describes our initial results using the AGXP during CAS for the treatment of carotid artery stenosis.

Successful percutaneous transluminal angioplasty and stenting for symptomatic intracranial vertebral artery stenosis using intravascular ultrasound virtual histology

This is the first report of percutaneous transluminal angioplasty (PTA) of an intracranial artery applying intravascular ultrasound virtual histology (IVUS-VH), which has been recently developed for tissue characterization of coronary artery plaque. We report a case of successful PTA and stenting for symptomatic intracranial vertebral artery stenosis using IVUS-VH.

ENHANCEMENT PATTERN OF NORMAL EXTRAOCULAR MUSCLES IN DYNAMIC CONTRAST-ENHANCED MR IMAGING WITH FAT SUPPRESSION

PURPOSE To evaluate the internal structure of normal extraocular muscles on fat-suppressed dynamic contrast-enhanced MR imaging. MATERIAL AND METHODS Ten subjects were examined using fat-suppressed dynamic contrast-enhanced MR imaging. We evaluated the enhancement pattern (C-shaped or ring-like) of extraocular muscles and quantified the maximum ratios of enhancement (Rmax) and maximum ratios of signal increase (Vmax). We also quantified Rmax and Vmax in the central and peripheral portions of medial rectus muscles. RESULTS In the early phase of dynamic contrast-enhanced MR imaging, a C-shaped or ring-like pattern was observed in 100% of inferior rectus, 95% of medial rectus, 55% of superior rectus, 20% of lateral rectus, and 15% of superior oblique muscles. Overall mean Rmax and Vmax values showed statistically significant differences to the temporal muscles. For the peripheral portion of medial rectus muscles, mean Rmax and Vmax values were greater than for the central portion. CONCLUSION Using fat-suppressed dynamic contrast-enhanced MR imaging, the C-shape or ring-like internal structure of the extraocular muscles could be visualized, and were considered to reflect their structure of orbital and global layers. Potential usefulness of the fat-suppressed dynamic contrast-enhanced MR imaging for detecting pathological status is suggested.

Evaluation of extraocular muscles using dynamic contrast enhanced MRI in patients with chronic thyroid orbitopathy

Objective: The purpose of the current study is to investigate the underlying pathophysiological changes of extraocular muscle (EOM) in Graves orbitopathy using dynamic contrast MR imaging and to correlate these MR functional changes with the anatomic abnormalities. Methods: EOMs of 16 patients with Graves disease and 12 normal volunteers were examined by dynamic enhanced MRI. We quantified the peak enhancement ratio of EOMs and calculated the ratio versus temporalis muscle and the ratio of maximum upslope versus temporalis muscle. We compared the ratios between normal volunteers and patient groups. Results: Mean of peak enhancement ratio values for the EOMs in patients with Graves disease tends to decrease according to the severity of the anatomic and clinical changes. The mean maximum upslope also decreased according to the severity of the disease for EOMs. Conclusion: Hemodynamic information obtained by dynamic contrast enhanced MRI is useful in evaluating the clinical course of thyroid orbitopathy.

Initial experience of carotid artery stenting using the Carotid WALLSTENT and FilterWire EZ in Japan.

PurposeThe Carotid WALLSTENT (CWS) and Filter-Wire EZ (FWEZ) embolic protection devices for use in carotid arterial stenting (CAS) were newly approved for national health insurance coverage in Japan in April 2010. This article describes our initial experience of CAS using the CWS and FWEZ.Material and methodsA group of 14 patients (12 men, 2 women; mean age 70.1 years, range 59–83 years) with 15 carotid artery stenoses at high risk for carotid endarterectomy were treated by CAS using the CWS and FWEZ. Of these stenoses, 5 were symptomatic with ≥50% stenosis of the common or internal carotid artery (ICA), and 10 were asymptomatic with ≥80% stenosis. The rates of technical success, ICA flow impairment during filter protection, periprocedural ischemic stroke, 30-day major adverse events (MAEs) (stroke, death, myocardial infarction), and development of new ischemic lesions on diffusion-weighted imaging (DWI) were assessed.ResultsCAS was successful in all cases. There was no ICA flow impairment, periprocedural ischemic stroke, or MAEs. DWI showed new ipsilateral ischemic lesions in only one patient (6.7%).ConclusionOur initial clinical experience using the CWS and FEWZ for CAS was generally excellent, and the incidence of postprocedural ischemic lesions was low.

Multiple cerebral aneurysms associated with Takayasu arteritis successfully treated with coil embolization

The cerebrovascular complications of Takayasu arteritis are primarily related to the presence of occlusive lesions. Cerebral aneurysms rarely occur as complications; only 18 cases have been reported thus far. The use of coil embolization to treat cerebral aneurysms occurring as a complication of Takayasu arteritis has not been previously reported. We report a case of Takayasu arteritis with a basilar tip aneurysm and a P1 segment aneurysm of the left posterior cerebral artery that were successfully treated with coil embolization. Because coil embolization for cerebral aneurysms associated with Takayasu arteritis requires the use of limited access routes that have extremely curved and tortuous courses, catheter navigation was difficult. The guide catheter, microcatheter, and guidewire must be selected and navigated with greater care than is usually required for common aneurysm embolization.

Structure of the Medullary Veins of the Cerebral Hemisphere and Related Disorders

Deep medullary veins drain into subependymal veins with four convergence zones and show parallel distribution patterns adjacent to the body or inferior horn and a radial pattern in the frontal horn or trigon of the lateral ventricle. As white matter imaging develops such as diffusion tensor imaging or susceptibility-weighted imaging, requirements for understanding of white matter structures are increasing, not only for understanding of neuronal tracts but also for that of other structures including the fine anatomy of white matter vessels. Some disorders are related to deep medullary veins and show characteristic distributions of the lesions indicating the relationship to the medullary veins. When lesions show a parallel or radial distribution pattern in the certebral deep white matter, disorders related to deep medullary veins should be considered for differential diagnosis. In this review, we discuss disorders related to deep medullary veins, including (a) anomalies of the medullary veins, (b) hemorrhagic disorders related to the medullary veins (diffuse vascular injury due to high-energy trauma, deep medullary vein engorgement/thrombosis in neonates), (c) inflammatory changes that spread along the medullary veins, (d) neoplasms within the medullary veins, and (e) metabolic changes that lead to altered visualization of medullary veins. Understanding the anatomic structure of medullary veins in the cerebral hemisphere and becoming familiar with disorders in which the medullary veins play a major role in disease development may be helpful in the interpretation of brain images. ©RSNA, 2017.