Hidetaka Mitsumura

Findings of segmental zoster paresis on MRI

A 72-year-old man developed herpes zoster rash involving the left C3-5 dermatomes. The patient was receiving treatment for myasthenia gravis, which was very well controlled with oral prednisolone (25 mg). There was no muscle weakness or other complications on examination in the outpatient clinic. Ten days before the onset of rash, he noticed weakness of the left arm. On admission, the left arm weakness was limited to muscles controlled by the C5 myelomere. He had no clinical symptoms of myelitis, but the T2-weighted magnetic …

Olfactory function combined with morphology distinguishes Parkinson's disease

OBJECTIVE This study aimed to examine whether the volume of the olfactory bulbs and tracts (OB & T) on magnetic resonance imaging (MRI) is useful for differentiating Parkinsons disease (PD) from PD-related disorders. METHODS The study group comprised 13 patients with PD, 11 with multiple system atrophy (MSA), five with progressive supranuclear palsy, and five with corticobasal degeneration (PSP/CBD). All patients were evaluated using the odor stick identification test for Japanese (OSIT-J), (123)I-meta-iodobenzylguanidine (MIBG) scintigraphy, and brain MRI. OB & T areas on 1-mm-thick coronal images were measured and summed for volumes. We examined relationships between olfactory function and volume, and cardiovascular dysautonomia. We defined the cut-off values for OSIT-J score or MIBG uptake and OB & T volume to discriminate PD from PD-related disorders and calculated the proportional rate of PD in four categorized groups. RESULTS OB & T volume was smaller in PD than in MSA or PSP/CBD (p < 0.05 each). The cut-off for detecting PD patients was OSIT-J score <8, heart/mediastinum ratio <1.6, and OB & T volume <270 mm(3). In the group with OSIT-J score <8 and OB & T volume <270 mm(3), the proportion of PD patients among all patients with PD-related disorders was 91%. The rate of probable PD gradually increased as OSIT-J score and OB & T volume decreased (p < 0.001). CONCLUSIONS Although preliminary, these data obtained from a combined morphological and functional evaluation of OB or cardiovascular dysautonomia could be useful for further differential of PD and other PD-related disorders.

Stroke patients with cerebral microbleeds on MRI scans have arteriolosclerosis as well as systemic atherosclerosis.

Cerebral microbleeds (CMBs) are recognized as a manifestation of arteriolosclerosis in cerebral small vessels. However, little is known regarding whether stroke patients with CMBs often have systemic atherosclerosis. The aim of the present study was to elucidate this issue using the cardio–ankle vascular index (CAVI), a new index of systemic atherosclerosis, in acute ischemic stroke patients. We prospectively studied 105 patients (71 males, median age=70.0 years) with acute ischemic stroke. All of the patients were examined using T2*-weighted gradient echo magnetic resonance imaging (MRI) to look for and assess the CMBs and using fluid-attenuated inversion recovery to evaluate white matter hyperintensity (WMH). We assigned the patients into CMB and non-CMB groups and compared the clinical characteristics of these groups. The factors associated with CMBs were investigated using multivariate logistic regression analysis. T2*-weighted gradient echo MRI revealed CMBs in 47 patients (44.8%) and no CMBs in 58 patients (55.2%). The CAVI was significantly higher in the CMBs group (10.5 vs. 8.6, P<0.001). In the multivariate logistic regression analysis, CAVI per one point increase (odds ratio (OR), 1.50; 95% confidence interval (CI), 1.12–2.00; P=0.006), advanced WMH (OR, 4.78; 95% CI, 1.55–14.74; P=0.006) and impaired kidney function (OR, 3.31; 95% CI, 1.16–9.81; P=0.031) were independent factors associated with the presence of CMBs. A high CAVI was independently associated with CMBs in patients with acute ischemic stroke. Our results indicated that ischemic stroke patients with CMBs may have cerebral arteriolosclerosis as well as systemic atherosclerosis.

Relationship between Vertebral Artery Hypoplasia and Posterior Circulation Ischemia.

PURPOSE Vertebral artery hypoplasia (VAH) is a common congenital anatomical variation. In previous reports, it was unclear whether VAH was an independent risk factor for posterior circulation ischemia. The purpose of this study was to evaluate the impact of VAH on posterior circulation ischemia. METHODS Subjects were patients with acute ischemic stroke who underwent brain magnetic resonance imaging (MRI) and carotid ultrasonography. Diagnostic criteria for VAH were as follows: (1) Vertebral artery (VA) diameter less than 2.5 mm; (2) VA diameter less than 3.0 mm and a difference in length equal to or greater than 1:1.7; (3) VA diameter less than 3.0 mm, peak systolic velocity less than 40 cm/second, and resistance index value greater than .75. The patients were categorized by the location of the ischemic stroke on MRI as follows: lesion in posterior circulation (P group), lesion in anterior circulation (A group), and multiple lesions in both the anterior and posterior circulations (AP group). RESULTS We evaluated 129 consecutive patients. VAH was seen in 39, and VA occlusion was found in 15. The prevalence of VAH in the P group (44.4%) was significantly higher than that in the A + AP group (24.7%, P = .034). Multivariate regression analysis showed that large-artery atherosclerosis (odds ratio, 6.3; 95% confidence interval [CI], 1.3-30.1), posterior circulation ischemia (odds ratio, 12.0; 95% CI, 2.8-51.2), and VAH (odds ratio, 4.2; 95% CI, 1.2-15.0) were independent factors related to VA occlusion. CONCLUSION VAH was an independent factor related to VA occlusion. Therefore, VAH likely plays a role in posterior circulation ischemia.

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.

Substantial fluctuation of acoustic intensity transmittance through a bone-phantom plate and its equalization by modulation of ultrasound frequency.

For safe and efficient sonothrombolysis therapies, accurate estimation of ultrasound transmittance through the human skull is essential. The present study clarifies uncertainty surrounding this transmittance and experimentally verifies the equalization of transmittance through the modulation of ultrasound frequency. By changing three factors (ultrasound frequency, the thickness of a bone-phantom plate, and the distance between a transducer and a bone-phantom plate), we measured the intensity of ultrasound passing through the plate. Two activating methods, sinusoidal waves at 500 kHz and modulated waves, were compared. When we changed (1) the distance between a transducer and a bone-phantom plate and (2) the thickness of the bone-phantom plate, ultrasound transmittance through the plates substantially fluctuated. The substantial fluctuation in transmittance was observed also for a cut piece of human temporal skull bone. This fluctuation significantly declined for the modulated wave. In conclusion, modulation of ultrasound frequency can equalize the transmittance with an approximately 30-65% fluctuation drop and an approximately 40% fluctuation drop for a bone-phantom plate and for a cut piece of skull bone, respectively. By using modulated waves, we can develop safer and more effective sonothrombolysis therapies.

An uncovered risk factor of sonothrombolysis: Substantial fluctuation of ultrasound transmittance through the human skull

&NA; Sonothrombolysis is one of the most feasible methods for enhancing clot lysis with a recombinant tissue plasminogen activator (rt‐PA) in cases of acute ischemic strokes. For safe and efficient clinical practices of sonothrombolysis, accurate estimation of ultrasound transmittance through the human skull is critical. Previously, we reported substantial and periodic fluctuation of ultrasound transmittance through a bone‐phantom plate following changes to ultrasound frequency, the thickness of the bone‐phantom plate, and the distance between a transducer and the bone‐phantom plate. In the present study, we clarify the transmittance behavior of medium‐frequency ultrasound (from 400 kHz to 600 kHz) through the human skull, and examine reduction of the transmittance fluctuation. For the study, we measured transmittance of sinusoidal ultrasound waves at 400 kHz, 500 kHz, and 600 kHz at 13 temple spots on 3 human skulls by changing the distance between a transducer and the skull bone, and found substantial and periodic fluctuation in the transmittance behaviors for these sinusoidal voltage excitations. Degrees of the fluctuation varied depending on the measurement spots. A fluctuation ratio between the maximum transmittance and the minimum transmittance reached 3 in some spots. This large transmittance fluctuation is considered to be a risk factor for sonothrombolysis therapies. We examined a modulated ultrasound wave to reduce the fluctuation, and succeeded in obtaining considerable reduction. The average fluctuation ratios for 400‐kHz, 500‐kHz, and 600‐kHz waves were 2.38, 2.38, and 2.07, respectively. We successfully reduced the ratio to 1.72 by using a periodic selection of random frequency (PSRF)‐type of modulation wave. The thus obtained results indicate that attention to the fluctuation in ultrasound transmittance through the skull is necessary for safe and effective sonothrombolysis therapies, and that modulated ultrasound waves constitute a powerful method for reducing the risk of fluctuation. HighlightsWe measured ultrasound transmittance through the human skull for several frequencies around 500 kHz.We found substantial and periodic fluctuation in the ultrasound transmittance.This fluctuation significantly declined with the use of modulated ultrasound.

Transcranial Color Flow Imaging Can Evaluate the Severity of Periventricular Hyperintensity

BACKGROUND The goal of this study was to investigate the relationship between white matter lesions on magnetic resonance imaging and flow parameters in the middle cerebral artery (MCA) measured by transcranial color flow imaging. METHODS Patients with acute ischemic stroke or transient ischemic attack were included. The relationship between severities of periventricular hyperintensity (PVH) and ultrasonographic parameters in the MCA was investigated. The frequency of PVH was calculated for different categories according to the presence or absence of 2 considerable parameters according to the value of area under the receiver operating characteristic curve. RESULTS MCA flow was successfully measured in 203 temporal windows among 124 patients. After determining the cutoff value of end-diastolic velocity (EDV) and pulsatility index (PI) for the presence of PVH, 4 different categories were established: Category A, EDV more than 40 cm/second and PI less than .7; Category B, EDV more than 40 cm/second and PI more than .7; Category C, EDV less than 40 cm/second and PI less than .7; and Category D, EDV less than 40 cm/second and PI more than .7. The prevalence of PVH gradually increased along with category (P < .01). CONCLUSIONS The evaluation of MCA parameters using the combination of PI and EDV may be useful for the prediction of PVH.

Stiffness Parameter β of Cardioembolism Measured by Carotid Ultrasound Was Lower Than Other Stroke Subtypes

BACKGROUND We estimated the stiffness parameter β (β value), which is useful in the assessment of premature atherosclerosis, among patients with different subtypes of cerebral infarction (CI; eg, small-vessel occlusion, large-artery atherosclerosis, cardioembolism, and other determined and undetermined etiologies) to determine the clinical utility of the β value in classification of stroke patients into CI subtypes. METHODS Carotid ultrasonography (ALOKA ProSound SSD-alpha10) was performed in 31 CI patients and 38 control subjects, and the β value of the bilateral common carotid artery at 2.0 cm proximal to the bifurcation was measured using the echo-tracking method. The relationship between β value and age was examined, and the β value was compared among the different CI subtypes. RESULTS Positive β value correlated with age in control subjects (R=.69, P<.001) but not in CI patients (R=-.01, P=.996). There was no significant difference in the β value when comparing control patients and patients with cardioembolic stroke (P=.106), but the β value were lower in patients with cardioembolic stroke than in patients with noncardioembolic stroke (eg, small-vessel occlusion, large-artery atherosclerosis, and others, P=.009). CONCLUSIONS The β value was lower in patients with cardioembolic stroke than in patients with noncardioembolic stroke. The β value may be useful for estimating the risk of different stroke subtypes.

Clinical characteristics associated with corticospinal tract hyperintensity on magnetic resonance imaging in patients with amyotrophic lateral sclerosis

OBJECTIVE The usefulness of conventional magnetic resonance imaging (C-MRI) for diagnosing amyotrophic lateral sclerosis (ALS) remains controversial. The aim of this study was to investigate the utility of C-MRI in identifying ALS, specifically the association between corticospinal tract (CST) hyperintensity on C-MRI and clinical characteristics in patients with ALS. METHODS Between June 2008 and April 2012, we retrospectively enrolled consecutive patients diagnosed with sporadic ALS who underwent C-MRI. Patients with ALS were classified as definite-phase ALS (D-ALS) and indefinite-phase ALS (ID-ALS). We focused on the hyperintensity of T2-weighted images in the CST in patients with ALS. Based on the MRI results, we divided patients into two groups: a positive CST group showing CST hyperintensity; and a negative CST group with no such findings. Clinical characteristics of the two groups were compared. RESULTS Seventeen patients (median age, 62 years; 8 women, 9 men) were enrolled in this study, with D-ALS in eight (47%) and ID-ALS in nine (53%). Eight patients (47%) showed CST positivity. The rate of CST positivity was higher in patients with D-ALS (75%) than in patients with ID-ALS (22%, p=0.03). CONCLUSIONS CST positivity appears significantly increased in D-ALS patients. C-MRI can play an important role in diagnosing ALS.