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Featured researches published by Akihiro Uemura.


Academic Radiology | 2009

Prophylactic Vertebroplasty: Cement Injection into Non-fractured Vertebral Bodies During Percutaneous Vertebroplasty

Nobuo Kobayashi; Yuji Numaguchi; Sokun Fuwa; Akihiro Uemura; Masaki Matsusako; Yuka Okajima; Mitsutomi Ishiyama; Osamu Takahashi

RATIONALE AND OBJECTIVES We investigated the efficacy of prophylactic cement injection into the vertebral body adjacent to fractured vertebra to prevent new fractures after percutaneous vertebroplasty (PV). MATERIALS AND METHODS Between February 2002 to August 2004, PV was performed for osteoporotic compression fractures in 89 consecutive patients. All patients underwent PV for only fractured vertebrae. Between September 2004 and October 2006, we performed prophylactic cement injection for 155 patients, with cement injected into the non-fractured vertebra adjacent to the fractured vertebra, immediately above the fractured vertebra in the same procedure. We evaluated the frequency of new vertebral fractures and the efficacy of prophylactic therapy. RESULTS In the non-prophylactic group, 15 of 89 patients (16.8%) developed new fractures within 3 months and 20 of 89 patients (22.4%) developed new painful compression fractures within a year after the first PV. These fractures occurred mostly in adjacent vertebra, particularly in the vertebra immediately superior to the treated one and occurred in the lower thoracic and upper lumbar spine. In the prophylactic group, 7 of 155 patients (4.5%) developed new compression fractures within 3 months and 15 of 155 patients (9.7%) developed new compression fractures within 1 year. Statistical analysis showed that fewer new fractures developed in the prophylactic group than in the non-prophylactic group at both 3 months (P = .0020, Fishers exact test) and 1 year (P = .0079). CONCLUSIONS Prophylactic cement injection into non-fractured vertebrae adjacent to fractured vertebrae may prevent new compression fractures after vertebroplasty for osteoporotic patients.


Journal of Neurosurgery | 2014

Morphological and clinical risk factors for posterior communicating artery aneurysm rupture

Hidetoshi Matsukawa; Motoharu Fujii; Gensuke Akaike; Akihiro Uemura; Osamu Takahashi; Yasunari Niimi; Masaki Shinoda

OBJECT Recent studies have shown that posterior circulation aneurysms, specifically posterior communicating artery (PCoA) aneurysms, are more likely to rupture than other aneurysms. To date, few studies have investigated the factors contributing to PCoA aneurysm rupture. The authors aimed to identify morphological and clinical characteristics predisposing to PCoA aneurysm rupture. METHODS The authors retrospectively reviewed 134 consecutive patients with PCoA aneurysms managed at their facility between July 2003 and December 2012. The authors divided patients into groups of those with aneurysmal rupture (n = 39) and without aneurysmal rupture (n = 95) and compared morphological and clinical characteristics. Morphological characteristics were mainly evaluated by 3D CT angiography and included diameter of arteries (anterior cerebral artery, middle cerebral artery, and internal carotid artery), size of the aneurysm, dome-to-neck ratio, neck direction of the aneurysmal dome around the PCoA (medial, lateral, superior, inferior, and posterior), aneurysm bleb formation, whether the PCoA was fetal type, and the existence of other intracranial unruptured aneurysm(s). RESULTS Patients with ruptured PCoA aneurysms were significantly younger (a higher proportion were < 60 years of age) and a significantly higher proportion of patients with ruptured PCoA aneurysms showed a lateral direction of the aneurysmal dome around the PCoA, had bleb formation, and the aneurysm was > 7 mm in diameter and/or the dome-to-neck ratio was > 2.0. Multivariate logistic regression analysis showed age < 60 years (OR 4.3, p = 0.011), history of hypertension (OR 5.1, p = 0.008), lateral direction of the aneurysmal dome around the PCoA (OR 6.7, p = 0.0001), and bleb formation (OR 11, p < 0.0001) to be significantly associated with PCoA aneurysm rupture. CONCLUSIONS The present results demonstrated that lateral projection of a PCoA aneurysm may be related to rupture.


Journal of Neurology, Neurosurgery, and Psychiatry | 2014

Basilar extension and posterior inferior cerebellar artery involvement as risk factors for progression of the unruptured spontaneous intradural vertebral artery dissection

Hidetoshi Matsukawa; Masaki Shinoda; Motoharu Fujii; Osamu Takahashi; Akihiro Uemura; Yasunari Niimi

Background and purpose Spontaneous intradural vertebral artery dissection (siVAD) primarily causes stroke in young and middle-aged individuals; however, data on the relationship between vertebrobasilar morphology and the progression of siVAD are limited. Methods We retrospectively reviewed the data of 77 adult patients who were diagnosed with unruptured siVAD and treated conservatively. We analysed the clinical characteristics, vertebrobasilar morphologies and progression. Progression was defined as siVAD-induced stroke or morphological worsening of the siVAD. Results Twenty patients experienced progression. Recurrent ischaemic events that occurred in the vertebrobasilar territory were seen in three patients (3.9%). Two of these three patients and other 17 patients showed morphological worsening. None of the patients presented with subarachnoid haemorrhage. The log-rank test showed male sex, migraine, basilar extension and the posterior inferior cerebellar artery involvement were associated with the progression. Multivariate analysis using the Cox proportional hazards model showed that only basilar extension and the posterior inferior cerebellar artery involvement were significantly related to the progression (p=0.012 and 0.019). In addition, patients with these two vertebrobasilar morphologies had a significantly shorter period of progression of siVAD than those without these morphologies (both, median 242 days; one of two, median 1292 days; none, median 2445 days). Conclusions Thus, some vertebrobasilar morphologies might be markers of the progression of unruptured siVAD. Although all unruptured siVAD patients should be closely monitored, those with basilar extension and posterior inferior cerebellar artery involvement should perhaps be more carefully followed than those without such morphologies.


Radiation Medicine | 2007

Preprocedural MR imaging for percutaneous vertebroplasty: special interest in contrast enhancement.

Akihiro Uemura; Nobuo Kobayashi; Yuji Numaguchi; Sokun Fuwa; Yukihisa Saida

PurposeThe success of percutaneous vertebroplasty (PVP) depends greatly on preprocedural evaluation of the patients. The purpose of this study was to evaluate the efficacy of preprocedural magnetic resonance imaging (MRI) for the indications of PVP.Materials and methodsA retrospective review of 122 osteoporotic compression fractures in 63 patients who underwent preprocedural gadolinium-enhanced MRI and PVP was performed. Based on the extent of contrast enhancement on preprocedural MRI, each case was classified into one of two groups: group 1, which represented more than 50% of the vertebral body enhanced; and group 2, which represented less than 50% of the vertebral body enhanced. The most enhancing level was evaluated in multilevel PVP sessions. We evaluated the difference of pre- and postprocedural pain scales between groups 1 and 2 using Mann-Whitneys U-test.ResultsThere was a trend toward higher preoperative pain score in group 1, but it was not statistically significant (P = 0.0537). In addition, the postoperative pain score in group 2 was significantly higher than that in group 1 (P = 0.0007). The difference between the pre- and postoperative pain scores was significantly higher in group 1 than in group 2 (P = 0.0001).ConclusionContrast enhancement on MRI indicates a painful lesion and extensive contrast enhancement predicts better pain relief after PVP.


Brain Injury | 2016

Basilar dolichoectasia and the spontaneous intradural vertebral artery dissection

Hidetoshi Matsukawa; Masaki Shinoda; Motoharu Fujii; Akihiro Uemura; Osamu Takahashi; Yasunari Niimi

Abstract Object: Basilar dolichoectasia (BD) is an atherosclerotic, a distinct arteriopathy or a chronic-phase dissection characterized by elongation and dilation of the basilar artery. Spontaneous intradural vertebral artery dissection (siVAD) is an important cause of stroke in young and middle-aged people. It is hypothesized that the BD and the siVAD might partially share aetiologies and this study aimed to examine the relationship. Methods: This study compared clinical and radiological characteristics in 93 patients with siVAD with 93 controls. Ectasia was defined as basilar artery diameter >4.5 mm and dolichosis, as either basilar artery bifurcation above the suprasellar cistern or lateral to the margin of the clivus or dorsum sellae. The BD was defined if both ectasia and dolichosis were simultaneously observed. Multivariate logistic regression analysis was performed using variables that were marginally or significantly associated with siVAD on univariate analysis (p < 0.20). Results: Multivariate analysis showed siVAD patients have higher proportions of hypertension (OR = 2.4; 95% CI = 1.3–4.6; p = 0.007) and BD (OR = 3.7; 95% CI = 1.1–12; p = 0.036). Conclusions: The present study suggested that BD was related to the siVAD. A randomized study from multi-institutions with an adequate sample size is needed to make a strong argument about the association between BD and siVAD.


Journal of Stroke & Cerebrovascular Diseases | 2015

Inverse Relationship between Coffee Consumption and Cerebral Microbleeds in Men, but Not Women

Masaki Shinoda; Motoharu Fujii; Osamu Takahashi; Akiko Kawatsu; Akihiro Uemura; Yasunari Niimi

BACKGROUND Studies evaluating the association between coffee consumption and neurovascular diseases have frequently yielded contradictory results. The aim of this study was to investigate the association of coffee consumption with small-vessel disease (SVD) incidence in a healthy urban population while accounting for multiple demographic and lifestyle risk factors. METHODS This prospective study conducted from May 2013 through March 2014 included 455 participants (314 men and 141 women) aged 25 to 92 years. All subjects completed a questionnaire on coffee consumption and received a comprehensive neurologic examination, including magnetic resonance imaging, at St. Lukes International Hospital (Tokyo, Japan). RESULTS Incidence of SVD was lower in male daily coffee drinkers than male nondrinkers and occasional drinkers, whereas incidence of white matter lesions was lower in female daily coffee drinkers than female nondrinkers or occasional drinkers. In multivariate analyses including age, sex, smoking status, and BMI, as well as coffee consumption, incidence of microbleeds was significantly lower in male daily coffee drinkers compared to nondrinkers. CONCLUSIONS Daily coffee consumption is associated with reduced risk of cerebral microbleeds in men.


Journal of Neurosurgery | 2013

Morphological and clinical risk factors for the rupture of anterior communicating artery aneurysms

Hidetoshi Matsukawa; Akihiro Uemura; Motoharu Fujii; Minobu Kamo; Osamu Takahashi; Sosuke Sumiyoshi


American Journal of Neuroradiology | 2005

Percutaneous sacroplasty for hemorrhagic metastases from hepatocellular carcinoma

Akihiro Uemura; Masaki Matsusako; Yuji Numaguchi; Masaki Oka; Nobuo Kobayashi; Chikako Niinami; Tomonori Kawasaki; Koyu Suzuki


Academic Radiology | 2005

Intravertebral Cleft Sign on Fat-suppressed Contrast-enhanced MR

Masaki Oka; Masaki Matsusako; Nobuo Kobayashi; Akihiro Uemura; Yuji Numaguchi


American Journal of Neuroradiology | 2007

Effect on Partial Pressure of Oxygen in Arterial Blood in Percutaneous Vertebroplasty

Akihiro Uemura; Yuji Numaguchi; Masaki Matsusako; Nobuo Kobayashi; Y. Saida; M. Rahman

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Yuji Numaguchi

University of Rochester Medical Center

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Yuka Okajima

Brigham and Women's Hospital

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