Nobuaki Yamamoto

Brush Sign on 3-T T2*-Weighted MRI as a Potential Predictor of Hemorrhagic Transformation After Tissue Plasminogen Activator Therapy

Background and Purpose— The brush sign (BS) is the enlargement of medullary veins on 3-T T2*-weighted MRI seen in patients with ischemic stroke because of major cerebral artery occlusion. However, the clinical relevance of BS in patients with acute stroke remains unclear. We assessed the correlation between detecting BS with the development of hemorrhagic transformation after intravenous thrombolysis. Methods— We enrolled consecutive patients with M1 or M2 occlusion treated with intravenous tissue plasminogen activator. We classified the patients into 2 groups: the group positive for BS (P-BS) and the group negative for BS (N-BS). We investigated the differences in MRI findings and the clinical outcome between the 2 groups. Results— The subjects consisted of 36 patients (19 men; mean age, 74.7 years). Twenty-one patients (58%) had M1 occlusion, and 15 (42%) had M2 occlusion. Twenty-five patients (69%) were classified into the P-BS group and 11 (31%) into the N-BS group. Recanalization was observed in 15 (60%) and 10 (90%) patients in the P-BS and N-BS groups, respectively (P=0.116). Hemorrhagic transformation on MRI was observed more frequently in the P-BS group than in the N-BS group (64% versus 18%; P=0.027). A good outcome (mRS, 0–1) at discharge was found in 24% of patients in the P-BS group and in 45% of patients in the N-BS group (P=0.152). A multivariate logistic regression analysis revealed that the presence of BS (odds ratio, 9.08; 95% confidence interval, 1.4–59.8; P=0.022) was independently associated with hemorrhagic transformation. Conclusions— BS may predict the development of hemorrhagic transformation in patients with acute stroke treated with intravenous tissue plasminogen activator.

Intra-Arterial Signal on Arterial Spin Labeling Perfusion MRI to Identify the Presence of Acute Middle Cerebral Artery Occlusion

Background: The susceptibility vessel sign on gradient echo-type-T2*-weighted imaging is a well-known marker of arterial occlusion. Stagnant flow in front of the middle cerebral artery (MCA) occlusion sites may contribute to the intra-arterial, high-intensity signal on arterial spin labeling magnetic resonance imaging (MRI), making it another potential marker of MCA occlusion. We compared the intra-arterial, high-intensity signal and susceptibility vessel sign in patients with symptomatic MCA occlusion and patients without major vessel occlusion. Methods: We identified transient ischemic attack or ischemic stroke patients with (1) 3-T MRI performed within 24 h after clinical onset including arterial spin labeling, T2*-weighted imaging, and magnetic resonance angiography (MRA) and (2) either having MCA occlusion (n = 34 patients) or without major vessel occlusion (n = 24 patients). The intra-arterial, high-intensity signal was defined as an enlarged circular or linear bright hyperintensity within the artery. The susceptibility vessel sign was defined as an enlarged spot of hypointensity within the MCA, in which the diameter of the hypointense signal within the vessel exceeded the contralateral vessel diameter. The presence or absence of the intra-arterial, high-intensity signal and susceptibility vessel sign were assessed, along with their inter-rater agreement and consistency with the presence of MCA occlusion on MRA. Results: The intra-arterial, high-intensity signal was detectable in 30 patients (52%), and susceptibility vessel sign was observed in 17 patients (29%). The sensitivity of the intra-arterial high-intensity signal was significantly higher than that of the susceptibility vessel sign (88% vs. 50%; p < 0.05). The accuracy of the intra-arterial high-intensity signal was also higher than that of the susceptibility vessel sign (93% vs. 71%; p < 0.05). The intra-arterial high-intensity signal was situated in the proximal regions of the susceptibility vessel sign on T2*WI within the MCA. Neither the intra-arterial high-intensity signal nor the susceptibility vessel sign was observed in patients without major vessel occlusion. Inter-rater agreement was good for intra-arterial high-intensity signal detection (κ = 0.73) and moderate for susceptibility vessel sign detection (κ = 0.47). The presence or absence of the intra-arterial high-intensity signal was highly consistent with that of MCA occlusion on MRA (κ = 0.74). Conclusions: The intra-arterial high-intensity signal on arterial spin labeling appears to be useful to identify the presence of acute MCA occlusion and may be associated with stagnant flow in front of occlusion sites. The intra-arterial high-intensity signal may also be used to identify the occlusion site.

Two-layered susceptibility vessel sign on 3-tesla T2*-weighted imaging is a predictive biomarker of stroke subtype.

Background and Purpose— A susceptibility vessel sign (SVS) on 1.5-tesla (T)-T2*-weighted images may predict cardioembolism. It has also been detected in patients with large artery atherosclerosis. In patients with major vessel occlusion, the SVS was comprised 2 layers on 3T-T2*-weighted images. We assessed the efficacy of 2-layered SVS on 3T-T2*-weighted imaging scans for predicting cardioembolism. Methods— Our study included 132 patients who had ischemic stroke within the preceding 24 hours and presented with internal carotid artery or middle cerebral artery occlusion because of cardioembolism or large artery atherosclerosis. We compared 2-layered SVS and SVS on 3T-T2*-weighted imaging scans for their sensitivity, specificity, and diagnostic odds ratio for predicting cardioembolism. Results— We enrolled 132 patients (72 men; mean age, 74.5 years); of these, 63 (47.7%) were presented with cardioembolism. Although the sensitivity of SVS and 2-layered SVS for cardioembolism and large artery atherosclerosis was not statistically different (74.6% and 58.0%, respectively), the sensitivity of 2-layered SVS was significantly higher in patients with cardioembolism (42.9%) than those with large artery atherosclerosis (2.9%; P<0.001). The specificity and diagnostic odds ratio for 2-layered SVS for cardioembolism were 97.1% and 25.1; for SVS they were 42.0% and 2.1, respectively. Conclusion— The specificity of 2-layered SVS for cardioembolism was high. It may be useful for predicting cardioembolism and for the management of patients with acute ischemic stroke.

Optimal Timing of Diffusion-Weighted Imaging to Avoid False-Negative Findings in Patients With Transient Ischemic Attack

Background and Purpose— We aimed to investigate the optimal timing of diffusion-weighted imaging (DWI) in patients with transient ischemic attack (TIA). Methods— Seventy-three consecutive patients with TIA underwent DWI on admission (initial DWI) and at 24 hours after admission (second DWI). Patients were divided into 2 groups based on initial DWI findings in relation to the second examination: false negative (group 1) and other (group 2). The probability of initial false-negative findings was determined for each hour from TIA onset to initial DWI. Multivariate analysis was used to evaluate the independent risk factors associated with false-negative findings on initial DWI. Results— Of the 73 patients examined (56 men; mean age, 68 years), 9 (12%) were categorized into group 1. The latency from TIA onset to initial DWI was 1.7±0.6 hours for group 1 (range, 1–2.8 hours) and 3.3±2.6 hours for group 2 (range, 35 minutes to 12 hours). The probability of false-negative findings on initial DWI decreased in a time-dependent manner (25%, 21%, and 7% for 1, 2, and 3 hours, respectively), and no false-negative findings were observed on initial DWI performed at >3 hours from symptom onset. Short latency (⩽2 hours) from TIA onset to initial DWI was an independent risk factor related to false-negative findings (odds ratio, 13.11; 95% confidence interval, 1.07–161.38; P=0.045). Conclusions— If the duration between TIA symptom onset and initial DWI is <2 hours, a repeat examination should be performed to minimize the risk of false-negative findings.

YAMATO Study (Tissue-Type Plasminogen Activator and Edaravone Combination Therapy).

Background and Purpose— We investigated whether administration of edaravone, a free radical scavenger, before or during tissue-type plasminogen activator (tPA) can enhance early recanalization in a major arterial occlusion. Methods— The YAMATO study (Tissue-Type Plasminogen Activator and Edaravone Combination Therapy) is an investigator-initiated, multicenter (17 hospitals in Japan), prospective, randomized, and open-label study. Patients with stroke secondary to occlusion of the M1 or M2 portion of the middle cerebral artery and within 4.5 hours of the onset were studied. The subjects were randomly allocated to the early group (intravenous edaravone [30 mg] was started before or during tPA) and the late group (edaravone was started after tPA and the assessment of early recanalization). Results— One-hundred sixty-five patients (96 men; median age [interquartile range], of 78 [69–85] years) were randomized 1:1 to either the early group (82 patients) or the late group (83 patients). Primary outcome, defined as an early recanalization 1.5 hour after tPA, was observed in 53% of the early group and in 53% of the late group (P=1.000). About secondary outcomes, the rate of significant recanalization of ≥50% was not different between the 2 groups (28% versus 34%; P=0.393). The symptomatic intracerebral hemorrhage has occurred in 4 patients (5%) in the early group and in 2 patients (2%) in the late group (P=0.443). The favorable outcome (modified Rankin Scale score of 0–2) at 3 months was also similar between the groups (53% versus 57%; P=0.738). Conclusions— The timing of edaravone infusion does not affect the rate of early recanalization, symptomatic intracerebral hemorrhage, or favorable outcome after tPA therapy. Clinical Trial Registration— URL: http://www.umin.ac.jp/ctr/index-j.htm. Unique identifier: UMIN000006330.

Predictors of Neurologic Deterioration in Patients with Small-Vessel Occlusion and Infarcts in the Territory of Perforating Arteries

BACKGROUND It is difficult to predict neurologic deterioration in patients with small-vessel occlusion (SVO), that is, small infarcts in the territory of cerebral perforating arteries. METHODS We reviewed 110 patients with SVO who were admitted to our hospital. We divided them into groups with (n = 32, group 1) and without deterioration (n = 78, group 2) and evaluated their medical records, risk factors, magnetic resonance imaging findings, grade of periventricular hyperintensity (PVH), maximum diameter of the infarct area, and the number of slices showing infarcts on diffusion-weighted images (DWI). RESULTS Our study population consisted of 110 patients (71 males and 39 females; mean age 69.2 years): 32 (29%) did and 78 (71%) did not suffer deterioration. By univariate analysis, the age, current smoking, history of stroke, maximum diameter of the infarcted area, number of DWI slices with infarcts, frequency of PVH, and PVH grade based on Fazekas classification differed significantly between the 2 groups. By multivariate analysis, conventional risk factors other than PVH and history of stroke were not associated with neurologic deterioration (PVH grade ≥ 2 versus PVH grade ≤ 1, odds ratio 6.72, P = .006; with stroke versus without stroke, odds ratio .21, P = .049). We also found that higher the PVH grade, the worse the National Institutes of Health Stroke Scale score at the time of discharge. CONCLUSIONS PVH and without history of stroke are independently associated with neurologic deterioration in patients with SVO.

Usefulness of 3-Tesla magnetic resonance arterial spin-labeled imaging for diagnosis of cranial dural arteriovenous fistula

BACKGROUND AND PURPOSE Conventional digital subtraction angiography (DSA) has been a useful tool for the diagnosis of cranial dural arteriovenous fistula (cDAVF). In most patients with cDAVF, blood flow through the arteriovenous shunt was pooled at diseased veins and/or sinuses. Therefore, we speculated that pooled blood at diseased veins in patients with cDAVF could be detected on arterial spin-labeled imaging (ASL). The purpose of the present study was to investigate the usefulness of ASL to detect cDAVF. MATERIALS AND METHODS Consecutive 13 patients with cDAVF who were admitted to our hospital between April 2013 and September 2016 were included in our study. We performed magnetic resonance imaging (MRI), including ASL, before DSA and within 7days after treatment for all of our patients. The accuracy for diagnosis of cDAVF was compared between conventional MRI findings and ASL findings. We also investigated the difference in ASL findings before and after treatment. RESULTS We could detect venous ASL signals in 12 patients, and this was more sensitive for diagnosis of cDAVF versus conventional MRI findings. ASL found the same location of cDAVF as conventional angiography. After successful treatment, venous ASL signals disappeared. CONCLUSIONS ASL might be useful to detect cDAVF and predict the location of diseased sinuses.

Risk Factors of Neurological Deterioration in Patients with Cerebral Infarction due to Large-Artery Atherosclerosis.

BACKGROUND In some patients with acute ischemic stroke, neurological deterioration (ND) is observed, and it is difficult to predict at the time of admission. Especially in some patients with large-artery atherosclerosis (LAA), aggressive medical treatments and surgical interventions might be helpful to prevent ND. Therefore, we investigated factors associated with ND in patients with LAA. METHODS We studied patients with LAA who were admitted to our hospital. We divided them into 2 groups with (group 1) and without deterioration (group 2), and evaluated their medical records, risk factors, and radiological findings, such as number of diffusion-positive lesion and degree of stenosis. RESULTS Our study population consisted of 171 patients; 71 (41.5%) did and 100 (58.5%) did not suffer deterioration. By univariate analysis, blood pressure (BP), heart rate, National Institutes of Health Stroke Scale (NIHSS) score, number of diffusion-positive lesion, count of red blood cell, high-density lipoprotein, and degree of stenosis differed significantly between the 2 groups. By multivariate analysis, systolic BP (≥170 mm Hg, odds ratio: 7.20, P <.001) was associated with ND. Furthermore, number of diffusion-weighted image (DWI)-positive lesion (≥8), degree of stenosis (>80.0%), and NIHSS score (≥4) were also independent factors associated with ND. CONCLUSIONS High BP, severity of neurological deficit at the time of admission, and radiological findings, such as degree of stenosis and number of DWI-positive lesion, are independently associated with ND in patients with LAA.

Late-onset myasthenia gravis is predisposed to become generalized in the elderly

Objective The continuous increase in the number of patients presenting with late-onset myasthenia gravis (LOMG) underscores the need for a better understanding of the clinical course and the establishment of an optimal therapeutic strategy. We aimed to clarify factors associated with clinical outcomes in LOMG. Methods We retrospectively reviewed the clinical profiles of 40 patients with early-onset MG (EOMG) (onset age: 49 years or younger), 30 patients with non-elderly LOMG (onset age: 50–64 years), and 28 patients with elderly LOMG (onset age: 65 years or older) and compared the subgroups according to onset age and thymus status. The evaluated parameters were MGFA classification before treatment, MG-ADL score, complicating diseases, antibody titer, treatment, and MGFA post-intervention status. Results Elderly LOMG patients showed transition to generalized symptoms at a higher frequency and underwent thymectomy less frequently than EOMG and non-elderly LOMG patients (p < 0.001). The frequencies of crisis and plasmapheresis were significantly lower in thymectomized LOMG patients without thymoma than in thymectomized LOMG patients with thymoma or non-thymectomized LOMG patients (p < 0.01, P < 0.05, respectively). However, the outcome was not significantly different. All of the thymectomized LOMG patients without thymoma presenting with hyperplasia or thymic cyst had a favorable clinical course. Conclusions Our study showed that elderly LOMG patients are more prone to severity, suggesting that they require aggressive immunomodulatory therapy.

Dural arteriovenous fistula in the superior orbital fissure: A case report

Background: Dural arteriovenous fistulas (dAVFs) are extremely rare in the superior orbital fissure, and they exhibit ocular symptoms similar to the dAVF in the cavernous sinus because of the intraorbital venous congestion. Hence, the distinction of these conditions is imperative because of some inherent differences in endovascular treatment techniques. Case Description: A 58-year-old woman presented with a gradually worsening left eyeball protrusion and conjunctival congestion. The digital subtraction angiography revealed a dAVF with a shunting point in the left superior orbital fissure. Moreover, the inferolateral trunk of the left internal carotid artery and the left middle meningeal artery were involved as feeding arteries. Shunting blood flow drained into the facial vein through the superior ophthalmic vein (SOV) but not into the cavernous sinus, which was located just posterior to the superior orbital fissure. We performed transvenous coil embolization in the SOV through the facial vein, and the symptoms disappeared completely. Conclusion: We experienced a case of a dAVF in the superior orbital fissure. This case presented a possibility of the presence of one subtype of the dAVF in the part of the cavernous sinus separated at the superior orbital fissure in front. Transvenous coil embolization in the SOV through the facial vein efficiently occluded the fistula.