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.

Anterior cerebral artery notching on anterior optic pathways in a child with craniopharyngioma and progressive blindness.

We report the clinical significance of anterior cerebral artery (ACA) notching on the optic nerve and chiasm in a 3.5-year-old girl with a craniopharyngioma and progressive blindness. She presented with a headache and vomiting, followed by binocular blindness. Magnetic resonance imaging (MRI) studies demonstrated severely distended A1 segments and ill-depicted ACAs. Surgical decompression via a right subfrontal approach was performed to reverse blindness. Postoperative MRI studies showed good ACA visualization. A second operation via a right pterional approach revealed ACA notching, which appeared as a transverse groove on the right optic nerve and chiasm. ACA notching should be considered as a possible cause of progressive visual disturbance and a potential risk of ACA infarction in a child with a craniopharyngioma.

Magnetic resonance plaque imaging to predict the occurrence of the slow-flow phenomenon in carotid artery stenting procedures.

INTRODUCTION: The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a filter-type protection device. METHODS: Thirty-one carotid artery stenotic lesions in 30 patients (28 men and two women; mean age, 71.8 years) were evaluated by MR plaque imaging with black blood T1- and T2-weighted and time-of-flight sequences before CAS. Main plaque components were classified as vulnerable (intraplaque hemorrhage and lipid-rich/necrotic core) or stable (fibrous tissue and dense calcification) from the signal pattern. The plaque classification was statistically compared with the occurrence of slow-flow phenomenon. RESULTS: The slow-flow phenomenon was observed in ten CAS procedures (five flow arrests and five flow reductions). Flow arrests consisted of four vulnerable and one stable plaque, and flow reductions consisted of four vulnerable and one stable plaque. The slow-flow phenomenon occurred significantly (P<0.01) more frequently in patients with vulnerable plaque. CONCLUSIONS: Vulnerable carotid plaques have a significantly higher risk of slow-flow phenomenon than stable plaques. The occurrence of the slow-flow phenomenon can be predicted by MR plaque imaging before CAS.

A Case of Anti-CRMP5 Paraneoplastic Neurological Syndrome Induced by Atezolizumab for Small Cell Lung Cancer.

We herein report a 76-year-old man who developed irritability and forgetfulness 5 months after the introduction of atezolizumab for the treatment of small cell lung cancer (SCLC). Brain magnetic resonance imaging showed lesions of the striatum, and an investigation of the serum revealed a high titer of anti-CRMP5 antibody. After stopping atezolizumab and starting steroid pulse therapy, these clinical features improved. Given these findings, it is considered that CRMP5-assciated striatal encephalitis was induced by atezolizumab in this case with SCLC.

"Sukeroku sign" and "dent internal-capsule sign"--identification guide for targeting the subthalamic nucleus for placement of deep brain stimulation electrodes.

INTRODUCTION: The purpose of this study was to assess the usefulness of signs ("Sukeroku sign" and "dent internal-capsule sign") for the recognition of subthalamic nucleus (STN). MATERIALS AND METHODS: Five Parkinson's disease cases in which there was a successful placement of deep brain stimulation (DBS) electrodes at the STN were retrospectively reviewed. Five radiologists who were not engaged in localization of STNs in clinical practice were asked to locate the STNs before and after instructions on the signs. We evaluated the deviation between the reader-located points and the location of the DBS electrode for which there had been a successful installation. RESULTS: After instruction, there was a significant reduction in the deviation between the reader-located points and the DBS electrode. The time required for localization was also reduced after the instructions. CONCLUSION: Sukeroku sign and dent internal-capsule sign are feasible indicators of STN and seem to be useful in helping to identify the STN.

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. MATERIAL AND METHODS: A group of 15 patients (14 men) with a mean age of 72.3 years (range 53-81 years) were treated by CAS using the AGXP. Among them, 10 were symptomatic with >50% stenosis of the common or internal carotid artery (ICA), and 5 were asymptomatic with >70% stenosis. The rates of technical success, periprocedural stroke, ICA flow impairment, filter movement, and development of new ischemic lesions on diffusion-weighted imaging (DWI) were assessed. RESULTS: CAS using the AGXP was successful in all cases. There was one minor stroke, and flow impairment occurred in six patients. Filter movement averaged 1.9 vertebral bodies. DWI showed new ipsilateral ischemic lesions in eight of the patients. CONCLUSION: Initial clinical experience using the AGXP for CAS has been generally sufficient. However, attention must be paid to three problems when using the AGXP: the filter may move after placement; the filter may disturb blood flow in the ICA; and debris may pass around the filter.

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.

Cerebral hemorrhage with angiographic extravasation immediately after carotid artery stenting.

Recognizing cerebral hyperperfusion syndrome with intracerebral hemorrhage following carotid artery stenting is critical because the mortality rate is high. This type of hemorrhage usually arises from within several hours to a few days after the procedure. Here we describe a putaminal hemorrhage with extravasation during angiography that developed immediately after carotid artery stenting. A search of the literature revealed only one other similar case report. The etiology of the intracerebral hemorrhage immediately after carotid stenting might be analogous to that of hypertensive hemorrhage.

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.

Pituitary stalk compression by the dorsum sellae: possible cause for late childhood onset growth disorders.

PURPOSE: The purpose of this study was to evaluate the relationship between pituitary stalk compression by the dorsum sellae and clinical or laboratory findings in short stature children. MATERIALS AND METHODS: We retrospectively reviewed magnetic resonance images of the pituitary gland and pituitary stalk for 34 short stature children with growth hormone (GH) deficiency and 24 age-matched control cases. We evaluated the degree of pituitary stalk compression caused by the dorsum sellae. Body height, GH level, pituitary height and onset age of the short stature were statistically compared between cases of pituitary stalk compression with associated stalk deformity and cases without compression. RESULTS: Compression of the pituitary stalk with associated stalk deformity was seen in nine cases within the short stature group. There were no cases observed in the control group. There were no significant differences found for body height, GH level and pituitary height between the cases of pituitary stalk compression with associated stalk deformity and cases without compression. However, a significant difference was seen in the onset age between cases with and without stalk compression. CONCLUSION: Pituitary stalk compression with stalk deformity caused by the dorsum sellae was significantly correlated with late childhood onset of short stature.

CMOS-based opto-electronic neural interface devices for optogenetics.

CMOS-based opto-electronic neural interface devices are presented. The devices are designed with target application of in vitro and in vivo optogenetics. Two types of the opto-electronic neural interface devices are presented. One is single-chip type device for on-chip optogenetics, and the other is multi-chip type device with flexibility and wide-area coverage for in vivo optogenetics on brain. Design, packaging and functional evaluations are presented.

Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy.

BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect. METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side. RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery. CONCLUSION: Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.

Distinguishing between anterior cerebral artery and middle cerebral artery perfusion by color-coded perfusion direction mapping with arterial spin labeling.

The purpose of this study was to evaluate collateral circulation by describing anterior cerebral artery and middle cerebral artery perfusion areas. Pairs of image sets spin labeled on the medial and lateral side were used. A pixel-by-pixel t test was performed, with blue gradation used to display lateral perfusion (ie, middle cerebral artery) and orange gradation for anterior cerebral artery perfusion. Extensions of anterior cerebral artery perfusion areas in cases of middle cerebral artery stenosis were described. This method may aid in estimation of collateral circulation for stroke treatment.

Paradoxical parasellar high signals resembling shunt diseases on routine 3D time-of-flight MR angiography of the brain: mechanism for the signals and differential diagnosis from shunt diseases.

BACKGROUND AND PURPOSE: We occasionally encounter phenomena in which venous flow signals of the cavernous sinus (CS) and/or inferior petrosal sinus (IPS) are visualized paradoxically in patients without arteriovenous shunt in 3D time-of-flight magnetic resonance angiography (3D-TOF MRA) of the brain. The aims of this study are to examine the frequency and cause of this phenomenon ("pseudo-shunt" image) and to determine points of differentiation from definite arteriovenous shunt images ("real shunt"). METHODS: We retrospectively examined 85 maximum intensity projection images obtained by MRA in the absence of arteriovenous shunts to detect pseudo-shunt images, and evaluated source images of pseudo-shunt studies for venous structures. Four real-shunt MRA studies were compared with pseudo-shunt studies on three points: (1) extension of sinuses, (2) extension of cortical veins, and (3) signal intensity of sinuses as assessed by the scoring method (1 point when these findings exist, 0 when they do not). RESULTS: We detected five CS (3%) and six IPS (4%) signals in 9 (11%) of the 85 cases. In the source images of four pseudo-shunt images in the CS, we detected signals from the sphenoparietal sinus (SPS). The average score was significantly lower in the pseudo-shunt (0.22) than the real-shunt (2.75) images (P < .0001). CONCLUSION: In cerebral 3D-TOF MRA, pseudo-shunt images were seen in 11% (9/85) of the study population, with antegrade upward blood flow of the SPS considered as one of the causes. Real-shunt signals can be distinguished from pseudo-shunt signals by evaluation of source images.

Signal characteristics of FLAIR related to water content: comparison with conventional spin echo imaging in infarcted rat brain.

To examine the correlation between tissue water content and signal intensity on fluid-attenuated inversion recovery (FLAIR) images, we analyzed infarcted rat brain, verified the results by theoretical simulation, and compared them with conventional spin-echo images. We produced brain infarction with cavitation in five rats by middle cerebral artery occlusion. After in vivo MRI, histologic sections of the MRI plane were obtained. We measured the signal intensity of regions on FLAIR and spin-echo images, and measured the area of cavitation on histologic sections. We plotted curves of cavity percentage to signal intensity. Theoretical values were calculated using a two-compartment model. On the curve of cavity area to signal intensity, the signal on FLAIR images peaked in tissues with 20% to 30% area of cavitation. On the theoretical curve, the signal on FLAIR images peaked at 90% tissue water content. These results seem to be characteristic of FLAIR.

Hard-copy versus soft-copy image reading for detection of ureteral stones on abdominal radiography.

PURPOSE: The purpose of this study was to compare the usefulness of soft-copy images displayed on a cathode ray tube (CRT) with hard-copy images (film images) for detecting ureteral stones on abdominal radiography. MATERIALS AND METHODS: Five radiologists read images from 50 cases of ureteral stones and 50 normal cases diagnosed on the basis of intravenous urography and CT. For hard-copy reading, 10-bit images at 3,520x4,280 pixels obtained by computed radiography were printed on 14x17-inch films. For soft-copy reading, 8-bit images were displayed on a 17-inch monochrome monitor at 1,024x1,280 pixels. The study items were area under receiver operating characteristics (ROC) curve (Az), ureteral stone detection sensitivity and specificity, and reading time. RESULTS: For soft-copy and hard-copy images, the average Az values were 0.855 and 0.851, sensitivity was 62.8% and 62%, and specificity was 70.8% and 62.4%, respectively. There were no statistically significant differences between these values. Reading time was 106.6 min for soft-copy images, significantly longer than the 71.2 min for hard-copy images (p<0.05). CONCLUSION: Although soft-copy image reading time was longer than hard-copy image reading time, the ability to diagnose ureteral stones on abdominal radiography did not differ for soft- and hard-copy images.

[MR imaging provides important clues for the diagnosis of benign intracranial hypertension by all-trans retinoic acid in a patient with acute promyelocytic leukemia].

We report a case of benign intracranial hypertension (BIH) caused by all-trans retinoic acid (ATRA) in a patient with acute promyelocytic leukemia. A 21-year-old male was admitted to our hospital with pancytopenia. He was diagnosed as having acute promyelocytic leukemia due to increased promyelocytes, and PML-RAR alpha chimeric mRNA was detected. The administration of ATRA and idarubicin was started immediately. After 26 days of the chemotherapy, he complained of diplopia. Ophthalmologic examination revealed bilateral papilledema and hemorrhage. The cerebrospinal fluid showed an increase in pressure, but no other abnormalities. Computed tomography showed no intracranial abnormalities. The orbital MR imaging showed distension of the perioptic subarachnoid space and flattening of the posterior sclera. A diagnosis of BIH was made. After the discontinuation of ATRA, the symptoms improved and the MR abnormalities disappeared. As far as we know, there have been no reports illustrating MR abnormalities of BIH caused by ATRA, for the diagnosis and monitoring of which orbital MR imaging can provide important clues.