Takeshi Wada

Nagoya University, Nagoya, Aichi, Japan

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Publications (46)51.5 Total impact

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    ABSTRACT: Objective: This study aimed to assess the utility of dural thickening of the internal auditory canal (IAC) in patients with spontaneous intracranial hypotension (SIH) syndrome and determined the sensitivity and specificity of this image finding. Methods: Magnetic resonance images were evaluated for 22 cases of definite SIH and 16 cases of unlikely SIH. On contrast-enhanced magnetic resonance imaging, pachymeningeal enhancement and dural thickening of the IAC were assessed. Results: Pachymeningeal enhancement was observed in 21 of 22 patients in the definite SIH group and 1 of 16 patients in the unlikely SIH group (sensitivity, 95.5%; specificity, 93.8%). Dural thickening of the IAC was observed in 15 of 22 patients in the definite SIH group and 0 of 16 patients in the unlikely SIH group (sensitivity, 68.2%; specificity, 100%). Conclusions: Dural thickening of the IAC showed 100% specificity for SIH syndrome and can increase the accuracy of diagnosis of SIH syndrome.
    No preview · Article · Nov 2015 · Journal of computer assisted tomography
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    ABSTRACT: Background: Optimal antiplatelet inhibition is essential in patients undergoing neurointerventional procedures; however, variability in response to clopidogrel can contribute to thromboembolic and hemorrhagic complications. The present study evaluated the influence of diabetes mellitus and cigarette smoking on clopidogrel reactivity. Methods: Between 2011 and 2013, 71 consecutive patients underwent aneurysmal coil embolization (CE) or carotid artery stenting (CAS) and received clopidogrel (75 mg daily) and aspirin (100 mg daily) before the treatment. The patients were divided into 2 groups: CE (n = 31) and CAS (n = 40). The patients underwent prospective assessment of preoperative platelet function using VerifyNow assay and received adjunctive cilostazol (200 mg daily, triple antiplatelet therapy) in case of clopidogrel hyporesponse. Patients with clopidogrel hyper-response underwent clopidogrel dose reduction (clopidogrel, 12.5-50 mg daily). Results: Clopidogrel resistance was noted in 15 patients (37.5%) in the CAS group and in 4 patients (12.9%) in the CE group (P = .031). Clopidogrel hyper-response was noted in 2 patients (5%) in the CAS group and in 11 patients (54.8%) in the CE group (P < .001). There was a significant difference in the baseline clinical characteristics between the 2 groups. In the multivariate logistic regression analysis, diabetes and age were independent predictors of clopidogrel hyporesponse, whereas current smoker was an independent predictor of clopidogrel hyper-response. Conclusions: Significant differences in baseline clinical characteristics were present when comparing patients undergoing endovascular treatment of unruptured cerebral aneurysms and carotid artery stenosis. Diabetes mellitus and current smoker status were independent factors related to reactivity to clopidogrel.
    No preview · Article · Oct 2015 · Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association
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    ABSTRACT: Spontaneous dissecting aneurysm of the extracranial internal carotid artery is uncommon, and simultaneous onset of multiple dissecting aneurysms is rare in patients without congenital or traumatic risk factors. A few reports suggest that extracranial internal carotid artery dissecting aneurysms can grow after SAH due to another intracranial dissecting aneurysm. The present report describes two cases in which gradual growth of unruptured dissecting aneurysm of extracranial internal carotid artery occurred after SAH due to ruptured dissecting aneurysm of the vertebral artery and in which carotid artery stenting was subsequently performed. A 42-year-old man was admitted to our hospital with SAH due to ruptured left vertebral artery dissecting aneurysm and was managed surgically. Dissecting aneurysm of the right extracranial internal carotid artery was found and showed gradual growth. The aneurysm was treated with a stent at 7 weeks after onset. In another case, a 47-year-old woman presented with SAH due to ruptured right vertebral artery dissecting aneurysm and was managed surgically. Concomitant left extracranial internal carotid artery dissecting aneurysm was found and showed gradual growth. The aneurysm was treated with stent and coils. These are rare cases of multiple dissecting aneurysms that originated from different arteries simultaneously and that showed growth after SAH.
    No preview · Article · Aug 2015 · Turkish neurosurgery
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    ABSTRACT: We report the case of a 64-year-old male with internal carotid artery (ICA)-to-external carotid artery (ECA) steal due to severe stenosis of the common carotid artery (CCA). Left CCA occlusion was initially diagnosed on 3-dimensional time-of-flight magnetic resonance angiography, but digital subtraction angiography revealed severe stenosis of the left CCA and retrograde flow through the left ICA feeding the left ECA. Diverted blood flow from ECA to ICA in cases with occlusion or severe stenosis of the CCA represents a well-known alternative collateral flow pattern called ECA-to-ICA steal. However, collateral flow from ICA to ECA is rarely observed and may be termed ICA-to-ECA steal. We treated CCA stenosis in our patient by carotid artery stenting (CAS) because his CCA stenosis had been gradually progressing since the initial ischaemic attack. Antegrade ICA flow subsequently recovered. To the best of our knowledge, this is the first report of ICA-to-ECA steal normalised by the treatment of CCA stenosis using CAS.
    No preview · Article · May 2015
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    ABSTRACT: Spinal epidural arteriovenous fistulas (AVFs) with perimedullary venous drainage are rare. This report describes a case of lumbar epidural AVF in a patient with a history of endoscopic lumbar discectomy at the same level 8 years prior to presenting with progressive myelopathy secondary to retrograde venous reflux into the perimedullary vein. A 69-year-old man presented with progressive lower extremity weakness and sensory disturbance and loss of sphincter control 8 years after endoscopic lumbar discectomy for a disc herniation at L4-5 level. Magnetic resonance imaging showed spinal cord edema and dilated intradural perimedullary vessels. Spinal angiography revealed an epidural AVF at the site of the previous endoscopic lumbar surgery with intradural perimedullary venous drainage. The fistula was successfully occluded via endovascular transarterial embolization, and the patient had stabilization of his neurological deficits. Lumbar spinal epidural AVFs, especially those associated with iatrogenic trauma, are rare. Endoscopic surgical procedure can occlude the epidural venous plexus and disturb venous drainage, thereby inducing local venous hypertension and leading to epidural AVF with perimedullary venous drainage. This type of pathology should be considered within the differential diagnosis of delayed neurological deterioration after spinal surgery. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
    Full-text · Article · May 2015 · Interventional Neuroradiology
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    ABSTRACT: To investigate morphological changes of the superior and middle cerebellar peduncles (SCP, MCP) in spinocerebellar degeneration (SCD) by observing "cerebellar peduncle quarter notes". We examined 21 patients with SCD, including nine patients with multiple system atrophy cerebellar type (MSA-C), and 24 controls. We measured SCP angle and performed diffusion tensor analysis to quantify the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the MCP. We quantified the relationship between SCP angle and the ADC and FA of the MCP, and compared these variables between MSA-C patients and controls. There was statistically significant negative correlation between SCP angle and FA of the MCP, and a positive correlation between SCP angle and the ADC of the MCP. Mean SCP angle was larger among MSA-C patients than among normal controls. SCP angle tended to be larger among patients with severe degeneration of the MCP. The SCP angle, quantified by observing "cerebellar peduncle quarter notes", may be a simple index for evaluation of degeneration of the MCP.
    No preview · Article · Mar 2015 · Japanese journal of radiology
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    ABSTRACT: We report a case of a direct carotid-cavernous fistula (CCF) in a patient with Ehlers-Danlos syndrome type IV who presented with progressive chemosis and diplopia. To prevent potential lethal arterial wall injury due to the fragility of the arterial vessel wall, the ipsilateral carotid artery and internal jugular vein were surgically exposed for direct insertion of endovascular sheaths, and transvenous embolization was performed using triple microcatheters with detachable coils. The clinical course was uneventful, and chemosis and diplopia subsequently resolved. By the 6 month follow-up, MRI revealed no recurrence of the CCF. These techniques offer a unique access alternative for endovascular treatment, thereby reducing the risks associated with arterial dissection that often accompanies transfemoral access in this particular condition. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    No preview · Article · Nov 2014 · Journal of Neurointerventional Surgery
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    ABSTRACT: Hemorrhagic presentation of spinal epidural arteriovenous fistulas (AVFs) is rare in patients with cervical spinal vascular lesions. The present report describes a patient with cervical spine epidural AVFs associated with anterior spinal artery aneurysm at the same vertebral level presenting with subarachnoid hemorrhage. A 54-year-old man presented with sudden onset of headache. Computed tomography of the head showed subarachnoid hemorrhage. Diagnostic angiography revealed an epidural AVF located at the C1-2 level that was fed mainly by the dorsal somatic branches of the segmental arteries from the radicular artery and anterior spinal artery. This AVF drained only into the epidural veins without perimedullary venous reflux. Further, there was a 4-mm anterior spinal artery aneurysm in the vicinity of the fistula that was thought to be the cause of the hemorrhage. Endovascular transarterial fistulas embolization from the right radicular artery was performed to eliminate the AVF and to reduce hemodynamic stress on the aneurysm. No new symptoms developed after the treatment and discharged without neurological deficits. The aneurysm was noted to be reduced in size after the treatment and totally disappeared by 1 year later, according to follow-up angiography. Anterior spinal artery aneurysm from a separate vascular distribution may coexist with spinal epidural AVFs. In the setting of spinal subarachnoid hemorrhage, comprehensive imaging is indicated to rule out such lesions.
    No preview · Article · Oct 2014 · Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association
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    ABSTRACT: Background: Intracranial giant vertebral artery aneurysms are extremely rare in the pediatric population and are associated with significant morbidity and mortality. The present report describes a case of a pediatric patient with giant vertebral artery aneurysm who presented with intracranial mass effect. This patient was successfully treated with endovascular parent artery occlusion and coil embolization. Case Description: A 7-year-old girl presented with tetraparesis, ataxia, dysphagia, and dysphonia. Cerebral angiography revealed intracranial giant aneurysm arising from the right vertebral artery. The patient underwent endovascular parent artery occlusion alone to facilitate aneurysmal thrombosis as an initial treatment. This was done to avoid a coil mass effect to the brainstem. However, incomplete thrombosis occurred in the vicinity of the vertebral artery union. Therefore, additional coil embolization for residual aneurysm was performed. Two additional coil embolization procedures were performed in response to recurrence. Mass effect and clinical symptoms gradually improved, and the patient had no associated morbidity or recurrence at 2 years after the last fourth coil embolization. Conclusion: Intracranial giant vertebral artery aneurysms are rare and challenging in pediatric patients. Staged endovascular strategy can be a safe and effective treatment option.
    No preview · Article · Jun 2014 · Surgical Neurology International
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    ABSTRACT: The objective of this study was to determine long-term outcomes after stent placement for subclavian artery (SA) obstructive lesions assisted by intraoperative intravascular ultrasound (IVUS). The study included 25 lesions in 24 patients who underwent stent placement assisted by intraoperative IVUS for subclavian artery stenosis or obstruction at our hospital between January 2003 and August 2010. Outcome was evaluated based on the results within 30 postoperative days (technical success rate, improvement in upper extremity ischemia, steal syndrome, left-right blood pressure difference, and perioperative complications) and the results after 30 postoperative days (incidence of vertebrobasilar artery territory infarction and restenosis). Stent placement and vessel dilatation were successful in all patients, without perioperative complications. Upper extremity ischemia, steal syndrome, and left-right blood pressure difference disappeared in all cases. During follow-up observation (6-96 months; median 51 months), no restenosis occurred at the stent placement site in any patient. In one case, four years after initial treatment, stenosis was noted proximal to the stent placement site. Satisfactory long-term as well as short-term outcomes were achieved after stent placement for SA obstructive lesions assisted by intraoperative IVUS evaluation.
    No preview · Article · Apr 2014
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    ABSTRACT: Objective: We report a case of a fusiform aneurysm of vertebral artery, treated by second stent placement using stent-in-stent technique on down-the-barrel view (DBV) for a stent assisted coil embolization.Case presentation: A 60-year-old woman had a fusiform aneurysm of the right vertebral artery growing up in size during 1 year follow up. Stent-assisted coil embolization using an Enterprise stent was performed. During coil embolization with the initial Enterprise stent, coil migration to the parent artery was seen on DBV. The second Enterprise stent was deployed in a stent-in-stent manner. Following deployment of the second stent, coil migration to the parent artery disappeared with preserving the vessel lumen. Complete occlusion of the aneurysm and good patency of the parent artery were seen on 3 months’ follow up angiogram.Conclusion: Second stent placement using stent-in-stent technique may be effective for management of coil herniation to the parent vessel during stent-assist coil embolization for fusiform vertebral artery aneurysm.
    Preview · Article · Jan 2014
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    ABSTRACT: Periprocedural ischemic stroke is one problem associated with carotid artery stenting (CAS). This study was designed to assess whether preoperative statin therapy reduces the risk of periprocedural ischemic complications with CAS. In this prospective study at 11 centers, patients with carotid artery stenosis (symptomatic ≥50 %, asymptomatic ≥80 %) and a high risk of carotid endarterectomy but without previous statin treatments were divided into two groups by low-density lipoprotein cholesterol (LDL-C) levels. With LDL-C ≥120 mg/dl, the pitavastatin-treated (PS) group received pitavastatin at 4 mg/day. With LDL-C <120 mg/dl, the non-PS group received no statin therapy. After 4 weeks, both groups underwent CAS. Frequencies of new ipsilateral ischemic lesions on diffusion-weighted imaging within 72 h after CAS and cerebrovascular events (transient ischemic attack, stroke, or death) within 30 days were assessed. Among the 80 patients enrolled, 61 patients (PS group, n = 31; non-PS group, n = 30) fulfilled the inclusion criteria. New ipsilateral ischemic lesions were identified in 8 of 31 patients (25.8 %) in the PS group and 16 of 30 patients (53.3 %) in the non-PS group (P = 0.028). Cerebrovascular events occurred in 0 patients in the PS group and in 3 of 30 patients (10.0 %) in the non-PS group (P = 0.071). Multivariate analyses demonstrated the pitavastatin treatment (β = 0.74, 95 % confidence interval 0.070-1.48, P = 0.042) to be an independent factor for decreasing post-CAS ischemic lesions. Pretreatment with pitavastatin significantly reduced the frequency of periprocedural ischemic complications with CAS.
    Full-text · Article · Dec 2013 · CardioVascular and Interventional Radiology
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    ABSTRACT: PURPOSE Diffusion kurtosis is a statistical measure for quantifying the deviation of the water diffusion profile from a Gaussian distribution. The current study acessed the time course of diffusion kurtosis and evaluated the period of pseudo-normalization after cerebral infarctions. METHOD AND MATERIALS Subjects included 25 cases / 30 lesions of cerebral infarction. The duration between onset and imaging ranged from 1 day to 122 days. Diffusion kurtosis measurements were done with b values of 0, 1000, and 2000 sec/mm2 applied in 30 directions. Diffusion kurtosis images are generated, including axial kurtosis (Kax) and radial kurtosis (Krad) to the eigenvector. We also acquired T2 weighted image (T2WI), diffusion weighted image (DWI) and apparent diffusion coefficient (ADC) images. The time course of the relative values for T2WI, DWI, ADC, Krad, and Kax were evaluated and the period for pseudo-normalization was obtained. RESULTS The trend curve of relative Krad indicates that there was a trend for relative Krad to decrease according to the duration after infarction onset, and that lesions from 10 days to 2 weeks after infarction onset showed lower Krad values compared with the contralateral side. The trend curve of the relative Kax showed high values in cases within 10 days to 2 weeks after infarction onset. There was also a trend for relative Kax to decrease according to the duration after infarction onset, which represented the pseudo-normalization period. The days for pseudo-normalization were 45days, 21days, 14 days and 25 days for DWI, ADC, Krad and Kax respectively. CONCLUSION Diffusion kurtosis values showed increases in lesions early after infarction and showed decreases earlier than DWI. Krad showed pseudo-normalization earlier than that of ADC, and the pseudo-normalization of Kax was a little later than that of ADC. Because DKI can show different time courses after the onset of infarction compared with DWI or ADC, additional information for white matter tissue with infarction can be provided using this imaging technique. Specifically, information by DKI including Kax and Krad seems helpful in making detailed evaluation for the duration after onset of infarction in combination with T2WI, DWI and ADC. CLINICAL RELEVANCE/APPLICATION Since DKI can show different time courses, information by DKI including Kax and Krad seems helpful in making detailed evaluation for the duration after onset of infarction in addition to T2WI, DWI and
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: Optimal platelet inhibition is an important therapeutic adjunct in patients with carotid artery stenosis undergoing carotid artery stenting (CAS). Clopidogrel resistance is associated with increased periprocedural thromboembolic complications from neurovascular stent placement procedures. The addition of cilostazol to dual antiplatelet therapy (DAT) has been reported to reduce platelet reactivity and to improve clinical outcomes after percutaneous coronary intervention. This study was undertaken to evaluate the impact of adjunctive cilostazol in patients with CAS. Platelet function was assessed by light transmittance aggregometry using the VerifyNow assay. Sixty-four consecutive patients who underwent CAS received standard DAT, clopidogrel (75 mg daily), and aspirin (100 mg daily) more than 4 weeks before the procedure. From 2010 to 2011 (period I), 28 patients underwent CAS under standard DAT. From 2011 to 2013 (period II), 36 patients prospectively had preoperative assessment of platelet function, and 13 patients with clopidogrel resistance received adjunctive cilostazol (200 mg daily) in addition to standard DAT. The incidence of new ipsilateral ischemic lesions on diffusion-weighted imaging a day after CAS and ischemic or hemorrhagic events within 30 days was assessed. Clopidogrel resistance was indentified in 12 patients (43%) in period I and 13 patients (36%) in period II (P = .615). In period II, the addition of cilostazol significantly decreased P2Y12 reaction units and % inhibition (P = .006 and P = .005, respectively), and there was a significant difference in P2Y12 reaction units between the two periods. New ipsilateral ischemic lesions were significantly decreased in period II (2/36 patients) compared with period I (7/28 patients; P = .034); however, there was no significant difference in hemorrhagic and thromboembolic events between the two periods. Adjunctive cilostazol (triple antiplatelet therapy) in clopidogrel-resistant patients reduces the rate of clopidogrel resistance and suppresses new ischemic lesions without hemorrhagic complications, as compared with standard DAT. Antiplatelet management based on the evaluation of antiplatelet resistance would be required for prevention of perioperative thromboembolic complications in CAS.
    No preview · Article · Nov 2013 · Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter
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    ABSTRACT: The present study aimed to identify the types of curved lesions that are difficult to place Carotid Wallstent (CWS). The study targeted 31 consecutive carotid artery (CA) stenosis underwent carotid artery stenting using CWS. CWS placement success rate, stenosis location, lesion tortuosity, and relationship with stent placement failures were investigated. Lesion tortuosity was defined as the angle formed by 2 tangential lines between internal CA and common CA from the inflection point (IP) was defined as the center of lesion curvature. Stenosed lesions were classified into type A or B. Type A was defined as if the distal end of the stenosis was located proximal to the IP at a distance ≥0.5 of a vertebral body based on the posterior height of the 3rd vertebral body, otherwise was type B. The stent placement success rate was 93.5% (29/31). The 2 unsuccessfully stented lesions, both lesions were significantly different from other lesions by having a lesion tortuosity less than 90° and by belonging to type B. Since CWS placement is difficult in patients with CA stenosis located close to the IP at a lesion tortuosity ≤90°, open-cell stents should be considered as an alternative.
    Full-text · Article · Sep 2013 · SpringerPlus
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    ABSTRACT: PURPOSE In contrast enhanced (CE) CT in head and neck (HN) region, swelling of pharyngeal wall is sometimes observed after contrast agent (CA) administration compared to plain (P) CT (Figure). We made retrospective evaluation of clinical cases in order to assess the frequency and the relevance to anaphylactic reaction of the pharyngeal wall swelling. METHOD AND MATERIALS The subjects were 463 HN CE-CT (285 males and 178 females, average age 63.1) and 119 3D-CT angiography (CTA) examinations (93 males and 26 females, average age 71.3). In CE-CT, 100ml of 300mgI/ml CA was intravenously administrated with 1.0ml/sec, and 80ml of 370mgI/ml CA and 25ml of saline was administrated with 4.0ml/sec in 3D-CTA,. We defined the posterior hypopharyngeal wall as the reference region because the morphological change of the region was least in the volunteer scan. Two radiologists evaluated the CT images with agreement for the posterior hypopharyngeal wall swelling. The hypopharyngeal wall thickness (WT) was measured on CE and plain CT in the cases suspected the wall swelling and increase ratio {(WTCE - WTP) / WTP * 100} was calculated. The ratio over 30% was defined as significant wall swelling. The clinical information including anaphylactic reaction after CT was investigated. RESULTS Hypopharyngeal wall swelling was visually suspected in 41 cases (8.7%) in CE-CT and 16 (13.4%) in 3D-CTA and the significant hypopharyngeal wall swelling was found in 4 cases (0.9%) in CE-CT and 7 (5.9%) in 3D-CTA. The frequency of the hypopharyngeal wall swelling was significantly more in 3D-CTA than CE-CT by the Chi square test. No clinical symptom indicating the anaphylactic reaction was found in any cases during and after the CT examination. CONCLUSION The frequency of the hypopharyngeal wall swelling after the CA administration was higher in 3D-CTA than HN CE-CT, so the high blood concentration of CA was suspected to be related to the occurrence of the phenomenon. Although the hypopharyngeal wall swelling was suspected to be connected with the anaphylactic reaction, the finding was subclinical change in our evaluation. The symptomatic wall swelling related to anaphylactic reaction was supposed to have more severe morphological change and lower frequency. CLINICAL RELEVANCE/APPLICATION It should be known that the swelling of pharyngeal wall is sometimes observed in contrast enhanced CT in head and neck region but not always indicates an anaphylactic reaction.
    No preview · Conference Paper · Nov 2012
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    ABSTRACT: PURPOSE We examined the signal intensities of structures in the newborn brain on T1 weighted image (T1WI) and evaluate correlation between the signal intensities and the postnatal age or the gestational age at the examination. METHOD AND MATERIALS We evaluated the T1WI of consecutive 79 newborns who showed normal development after two years follow up. The gestational age ranged from 35 weeks 3 days to 46 weeks 6 days, and the postnatal age ranged from 8 days to 119 days. We performed qualitative grading for signal intensities of the structures including vermis, dentate nuclei, subthalamic nuclei, globus pallidus, fornix, splenium, pyramidal tracts in the precentral gyri, corona radiata, and internal capsule. Grading of the signal intensities on T1WI were as follows; Grade 1: higher than the cortex and close to the signal of fat, Grade 2: higher than the cortex, Grade 3: between the cortex and the surrounding structures, and Grade 4: indistinguishable from the surrounding structures. We correlated the signal grades with their gestational age and with the postnatal age at examination by using Kruskal-Wallis test. RESULTS There were statistically significant (p<0.01) positive correlations found between signal intensity and the gestational age at examination in the pyramidal tracts in the precentral gyri, corona radiata and internal capsule. In contrast, there were statistically significant (p<0.01) negative correlations found between signal intensity and the gestational age at examination in the cerebellar vermis, subthalamic nuclei, globus pallidus and fornix. CONCLUSION Maturation of the brain according to gestational age is associated with shortening of T1 relaxation time which is thought to be largely the result of myelination. The positive correlation between the gestational age and the signal of pyramidal tracts in the current study also support the effect of myelination. However, there were some structures which do not shows positive correlation to the gestational age but shows negative correlation to the postnatal age. Mechanism other than myelination may play role for the signal changes of the newborn brain in the structures such as subthalamic nuclei. CLINICAL RELEVANCE/APPLICATION On the T1WI of the newborn brain, there are structures showing high signal shortly after the birth such as subthalamic nucleus. It is important to know these structures for image interpretation.
    No preview · Conference Paper · Nov 2012
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    ABSTRACT: PURPOSE Diffusion kurtosis is a dimensionless statistical measure to quantifying the deviation of the water diffusion profile from Gaussian distribution. The purpose of the current study is to evaluate the changes in diffusion kurtosis in the cases with early cerebral infarction. METHOD AND MATERIALS The subjects of this study consist of the 15 cases with cerebral infarction. The duration between the onset and the imaging ranged from 3 hours to 5 weeks. Diffusion kurtosis image were acquired by using 3.0T clinical scanner (Siemens Magnetom Verio). An echo-planar diffusion weighted imaging sequence was used to acquire the diffusion kurtosis imaging data with b values of 1000 and 2000 sec/mm2 applied in distributed 30 directions. Diffusion kurtosis images are generated on the console of the imager (Siemens, work in progress), including axial (parallel) kurtosis to the eigenvector (Kax images) and radial kurtosis to the eigenvector (Krad images). We also evaluated diffusion weighted trace images (Dtrace images) generated from the same set of images. RESULTS In the population of the current study, there were 8 lesions of cerebral infarction within one week. In which, all 8 lesions showed high signal on Kax images, 3 lesion showed high signal on Krad images and all 8 lesions showed high signal on Dtrace images. Among the 5 lesions between one to 3 weeks, 2 lesions showed high signal on Kax images, no lesion showed high signal on Krad images and 5 lesions showed high signal on Dtrace images. Two lesions after 4 weeks of onset did not show high signal on three images. CONCLUSION Diffusion kurtosis value which is axial to the eigenvector showed increase in the lesions of the early infarction and showed earlier decrease compared to the diffusion weighted images. The results suggest large alteration in the intra-axonal diffusivity in the tissue of early infarction. Additional information for the tissue with very early infarction will be provided by diffusion kurtosis imaging. CLINICAL RELEVANCE/APPLICATION In the cases with early infarction, findings by diffusion kurtosis images made different behavior from the diffusivity. Additional information for the early infarction will be provided by this method.
    No preview · Conference Paper · Nov 2012
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    ABSTRACT: PURPOSE/AIM Movement disorder in elderly population is caused by various conditions. Neurodegenerative disease is one of the major causes among them. The purpose of this exhibit is to describe the role of imaging in the diagnosis of movement disorders and to illustrate this role with case-based presentations. CONTENT ORGANIZATION 1. Overview 2. Classification by the symptoms a) Parkinsonism and extra-pyramidal symptoms b) Involuntary movement c) Ataxia d) Motor weakness. 3. Classification by the causing substances a) Tauopathy b) Synucleinopathy c) TDP-43 proteinopathy 4. Role of imaging. Conventional and advanced techniques a) Conventional MRI b) MRS c) Diffusion imaging d) Susceptibility weighted imaging 5. Case-based presentations MSAs, SCAs, ALS etc. 6. Conclusion SUMMARY The diagnosis of movement disorders is a clinical challenge both for neurologist and neuroradiolgist. Conventional neuroimages still plays an important role in the diagnosis and management of these groups of entities as well as advanced images.
    No preview · Conference Paper · Nov 2012
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    ABSTRACT: BACKGROUND:: Retrograde leptomeningeal venous drainage (RLVD) in dural arteriovenous fistulas (DAVFs) is associated with intracerebral hemorrhage and nonhemorrhagic neurological deficits or death. Angiographic evidence of RLVD is a definite indication for treatment, but less-invasive methods of identifying RLVD are required. OBJECTIVE:: To evaluate the efficacy of susceptibility-weighted magnetic resonance imaging (SWI) in detecting RLVD in DAVFs. METHODS:: We retrospectively identified 17 DAVF patients who had angiographic evidence of RLVD and received treatment. Conventional angiography and SWI were assessed at pre- and post-treatment time points. The presence of RLVD on SWI was defined as cortical venous hyperintensity, and the presence of venous congestion on SWI venograms was defined as increased caliber of cortical or medullary veins. RESULTS:: Cortical venous hyperintensity was identified in pre-treatment SWI of 15 patients. Cortical venous hyperintensity was absent in early post-treatment SWI, consistent with the absence of RLVD in post-treatment angiography, in all but one of these patients. In two patients, cortical venous hyperintensity was identified during follow-up, indicating recurrence of RLVD. Cortical venous hyperintensity was not identified in pre-treatment SWI of two patients, despite angiographic evidence of RLVD. Venous congestion was identified in pre-treatment SWI venograms of 11 patients, and was of similar appearance to that identified from angiography. Venous congestive signs improved over the follow-up period. CONCLUSION:: The presence of SWI hyperintensity within the venous structure could be a useful indicator of RLVD in DAVF patients. SWI offers a noninvasive alternative to angiography for identification of RLVD in pre- and post-treated DAVF patients.
    No preview · Article · Oct 2012 · Neurosurgery