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Featured researches published by Hajime Ohta.


Neurosurgery | 1996

Prediction of hemorrhagic complications after thrombolytic therapy for middle cerebral artery occlusion: value of pre- and post-therapeutic computed tomographic findings and angiographic occlusive site.

Kiyotaka Yokogami; Shinichi Nakano; Hajime Ohta; Tomokazu Goya; Shinichiro Wakisaka

OBJECTIVEnTo evaluate the usefulness of pre- and post-therapeutic computed tomographic (CT) findings in predicting hemorrhagic complications, we retrospectively examined 35 patients treated with intra-arterial thrombolytic therapy for middle cerebral artery (MCA) occlusion.nnnMETHODSnThe presence or absence of early CT findings (loss of the insular ribbon, obscuration of the lentiform nucleus, and cortical effacement) and the presence and location of extravasation of contrast medium were evaluated on pre- and post-therapeutic CT scans, respectively. According to the angiographic occlusive site, the patients were classified into the following three groups: Group 1 (n = 13), MCA trunk occlusion involved lenticulostriate arteries; Group 2 (n = 11), occlusion of the MCA trunk without involvement of the lenticulostriate arteries; Group 3 (n = 11), occlusion of a branch of the MCA. Hemorrhagic complications (hemorrhagic transformation and/or massive brain swelling) were evaluated by reviewing CT scans obtained 3 to 14 days after thrombolytic therapy.nnnRESULTSnNo patient without extravasation (n = 17) showed hemorrhagic complications, and extravasation is the most useful finding in predicting hemorrhagic complications. There was significant correlation between extravasation and hemorrhagic complications (P < 0.01). In Groups 1 and 2, there was also significant correlation between early CT findings and hemorrhagic complications (P < 0.01), indicating that early CT findings are also useful in predicting hemorrhagic complications. In Group 1, 10 of 13 (76.9%) patients had both early CT findings and extravasation, and 6 of these 10 patients had hemorrhagic complications with clinical deterioration, suggesting the difficulty of thrombolytic therapy in this group. On the contrary, in Group 2, 8 of 11 (72.7%) patients had neither early CT findings nor extravasation and none of these 8 patients had hemorrhagic complications. In Group 3, however, early CT findings and extravasation had no correlation. Because the affected area was small in this group, it was difficult to evaluate cortical effacement. Although negative early CT findings did not always mean absence of extravasation and hemorrhagic complications in this group, the patients with hemorrhagic complications did not clinically deteriorate because of the small affected area.nnnCONCLUSIONnHemorrhagic complications could be predicted by evaluation of angiographic occlusive site and pre- and post-therapeutic CT findings.


Stroke | 2004

Appearance of Early Venous Filling During Intra-Arterial Reperfusion Therapy for Acute Middle Cerebral Artery Occlusion A Predictive Sign for Hemorrhagic Complications

Hajime Ohta; Shinichi Nakano; Kiyotaka Yokogami; Tsutomu Iseda; Takumi Yoneyama; Shinichiro Wakisaka

Background and Purpose— The purpose of this study was to evaluate the correlation between appearance of angiographic early venous filling during intra-arterial reperfusion therapy and posttherapeutic hemorrhagic complications. Methods— For the past 7 years, 104 patients prospectively underwent superselective local angiography via a microcatheter before and during intra-arterial reperfusion therapy for acute middle cerebral artery occlusion to evaluate the presence or absence of early venous filling. In principle, reperfusion therapy was discontinued just after appearance of early venous filling for fear of hemorrhage. There were 2 types of early venous filling: early filling of the thalamostriate vein from the lenticulostriate arteries and that of the cortical vein from the cortical arteries. Results— Among these 104 patients, 31 (29.8%) had early venous filling: 19 had early filling of the thalamostriate vein, and the other 12 had early filling of the cortical vein. Eight of the 19 patients (42.1%) and 2 of the 12 patients (16.7%) had massive hematoma with neurological worsening, whereas only 1 of the 73 patients (1.4%) without early venous filling had massive hematoma. There was a significant correlation between early venous filling and massive hematoma in both the deep (P <0.0001) and superficial (P =0.0019) middle cerebral artery territories. The sensitivity and specificity of the presence of early venous filling as an indicator of parenchymal hematoma were 71% and 83%, respectively. None of the 31 ischemic areas with early venous filling could escape cerebral infarction. Conclusions— Appearance of early venous filling may indicate irreversible brain damage and may be a predictive sign for parenchymal hematoma.


Stroke | 2013

Arterial Spin–Labeled Perfusion Imaging to Predict Mismatch in Acute Ischemic Stroke

Takeya Niibo; Hajime Ohta; Kazuma Yonenaga; Ichiro Ikushima; Shirou Miyata; Hideo Takeshima

Background and Purpose— We assigned a threshold to arterial spin–labeling (ASL) perfusion-weighted images (PWI) from patients with acute ischemic stroke and compared them with dynamic susceptibility contrast perfusion images to examine whether mismatch can be determined. Methods— Pseudocontinuous ASL was combined with dynamic susceptibility contrast PWI in 23 patients with acute ischemic stroke. Scans were obtained within 24 hours of symptom onset. PWI volumes were defined by ASL cerebral blood flow (<15, <20, and <25 mL/100 g per minute) and dynamic susceptibility contrast–mean transit time (MTT) thresholds (>10 s) that show a strong association with cerebral blood flow <20 mL/100 g per minute in Xenon CT studies. Agreement between the ASL–diffusion-weighted imaging and MTT–diffusion-weighted imaging mismatch and the correlation between penumbra salvage and infarct growth, defined as the difference between the baseline PWI and the baseline diffusion-weighted imaging lesion, respectively, and the final infarct volume were assessed. Results— The lesion volumes defined by MTT>10 s and ASL<20 mL/100 g per minute showed an excellent correlation. There was 100% agreement on the mismatch status between MTT>10 s and ASL<20 mL/100 g per minute. The correlation between infarct growth and penumbra salvage volume was significantly better for PWI lesions defined by ASL<20 mL/100 g per minute and MTT>10 s. Conclusions— In acute ischemic stroke, PWI lesions based on ASL threshold of <20 mL/100 g per minute can provide a reliable estimate of mismatch in correspondence at MTT threshold of >10 s.


Brain Tumor Pathology | 2014

A case of primary diffuse leptomeningeal gliomatosis

Kouji Yamasaki; Kiyotaka Yokogami; Hajime Ohta; Shinji Yamashita; Hisao Uehara; Yuichiro Sato; Hideo Takeshima

Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare and fatal disease characterized by diffuse infiltration of the leptomeninges by neoplastic glial cells without evidence of tumor in the brain parenchyma or spinal cord. We report a 60-year-old man with PDLG. He suffered transient right hemiparesis and generalized seizures. MRI showed diffuse leptomeningeal thickening and enhancement throughout the brain and spinal cord without any intraaxial involvement. Biopsy resulted in a diagnosis of glioblastoma with methylated MGMT promoter and wild-type IDH1. He underwent craniospinal radiotherapy and temozolomide treatment but despite concomitant adjuvant therapy he died 8xa0months after initial presentation.


International Journal of Angiology | 2000

A stump of occluded posterior cerebral artery mimicking a ruptured aneurysm: Case report

Shinichi Nakano; Kiyotaka Yokogami; Hajime Ohta; Shinichiro Wakisaka

We report on a 63-year-old female with subarachnoid hemorrhage who had a stump of occluded posterior cerebral artery (PCA) mimicking a ruptured aneurysm of the basilar bifurcation. Intraoperatively, the aneurysmal opacification on preoperative angiograms proved to be the residual lumen of the occluded right P1 segment. Because of the nodular appearance and upward direction of the stump of the right P1 segment, it was misinterpreted as an aneurysm. During operation, a tiny ruptured aneurysm missed on preoperative angiograms was found in the left A1-A2 junction and was clipped safely.


International Journal of Angiology | 1997

Direct percutaneous transluminal angioplasty for acute embolic middle cerebral artery occlusion: Report of two cases

Shinichi Nakano; Kiyotaka Yokogami; Hajime Ohta; Tomokazu Goya; Shinichiro Wakisaka

Two patients with cardioembolic middle cerebral artery (MCA) trunk occlusion were treated by direct percutaneous transluminal angioplasty (PTA).


International Journal of Angiology | 1998

MRA as a primary screening technique for intra- and extracranial arterial occlusive diseases

Kiyotaka Yokogami; Shinichi Nakano; Hajime Ohta; Tomokazu Goya; Shinichiro Wakisaka

We designed a protocol of 3-dimensional phase contrast (3D-PC-) magnetic resonance angiography (MRA), which was performed in the axial plane to assess the circle of Willis and in the coronal plane to assess the arteries of the head and neck, for screening of the intra- and extracranial arterial occlusive diseases. We evaluated the accuracy of 3D-PC-MRA comparing it with intraarterial angiography. In 52 consecutive patients presenting with clinical suspicion of a stroke, common carotid bifurcation (CCB), petrous segment of internal carotid artery (C5 segment), carotid siphon, middle cerebral artery (MCA), posterior cerebral artery (PCA), vertebral artery (VA), and basilar artery (BA) were evaluated. Both examinations were blindly graded as normal, mild (0–29% stenosis), moderate (30–69% stenosis), severe (70–99% stenosis), or occluded. In the two readers experienced and inexperienced in MR interpretation, Spearman rank correlations between the two techniques were 0.917/0.866 (CCB), 0.803/0.758 (C5 segment), 0.837/0.702 (carotid siphon), 0.841/0.787 (MCA), 0.899/0.886 (PCA), 0.935/0.889 (VA), and 0.932/0.900 (BA), respectively (p<0.0001). 3D-PC-MRA and intraarterial angiography had a good overall agreement, suggesting its use as a primary screening technique for intra- and extracranial arterial occlusive diseases, although the diagnostic accuracy of MRA was relatively poor in the C5 segment, carotid siphon, and MCA presumably due to phase dispersion.


Stroke | 2017

Prediction of Blood–Brain Barrier Disruption and Intracerebral Hemorrhagic Infarction Using Arterial Spin-Labeling Magnetic Resonance Imaging

Takeya Niibo; Hajime Ohta; Shirou Miyata; Ichiro Ikushima; Kazuchika Yonenaga; Hideo Takeshima

Background and Purpose— Arterial spin-labeling magnetic resonance imaging is sensitive for detecting hyperemic lesions (HLs) in patients with acute ischemic stroke. We evaluated whether HLs could predict blood–brain barrier (BBB) disruption and hemorrhagic transformation (HT) in acute ischemic stroke patients. Methods— In a retrospective study, arterial spin-labeling was performed within 6 hours of symptom onset before revascularization treatment in 25 patients with anterior circulation large vessel occlusion on baseline magnetic resonance angiography. All patients underwent angiographic procedures intended for endovascular therapy and a noncontrast computed tomography scan immediately after treatment. BBB disruption was defined as a hyperdense lesion present on the posttreatment computed tomography scan. A subacute magnetic resonance imaging or computed tomography scan was performed during the subacute phase to assess HTs. The relationship between HLs and BBB disruption and HT was examined using the Alberta Stroke Program Early Computed Tomography Score locations in the symptomatic hemispheres. Results— A HL was defined as a region where CBFrelative≥1.4 (CBFrelative=CBFHL/CBFcontralateral). HLs, BBB disruption, and HT were found in 9, 15, and 15 patients, respectively. Compared with the patients without HLs, the patients with HLs had a higher incidence of both BBB disruption (100% versus 37.5%; P=0.003) and HT (100% versus 37.5%; P=0.003). Based on the Alberta Stroke Program Early Computed Tomography Score locations, 21 regions of interests displayed HLs. Compared with the regions of interests without HLs, the regions of interests with HLs had a higher incidence of both BBB disruption (42.8% versus 3.9%; P<0.001) and HT (85.7% versus 7.8%; P<0.001). Conclusions— HLs detected on pretreatment arterial spin-labeling maps may enable the prediction and localization of subsequent BBB disruption and HT.


Journal of Neurotrauma | 2018

Determining if Cerebrospinal Fluid Prevents Recurrence of Chronic Subdural Hematoma: A Multi-Center Prospective Randomized Clinical Trial

Hiroyuki Toi; Yukihiko Fujii; Toru Iwama; Hiroyuki Kinouchi; Hiroyuki Nakase; Kazuhiko Nozaki; Hiroki Ohkuma; Hajime Ohta; Hideo Takeshima; Hironobu Tokumasu; Yuhei Yoshimoto; Masaaki Uno

Over the decades, the problem of postoperative recurrence of chronic subdural hematoma (CSDH) has not been resolved. The objective of our study was to investigate whether the recurrence rate of CSDH is decreased when artificial cerebrospinal fluid (ACF) is used as irrigation solution for CSDH surgery. The present study was a multi-center, prospective, randomized, open parallel group comparison test of patients enrolled from 10 hospitals in Japan. Eligible patients with CSDH were randomly assigned to undergo burr hole drainage with either normal saline (NS) or ACF irrigation. The primary end-point was postoperative recurrence of ipsilateral CSDH. A total of 402 patients with newly diagnosed CSDH were enrolled during the study period. After applying inclusion and exclusion criteria, and taking into consideration cases lost to follow-up, our final study cohorts consisted of 177 ACF patients and 165 NS patients, representing 85.7% of the initial cohort. The overall recurrence rate was 11.4%, occurring in 39 of the 342 analyzed patients during 90 days of follow-up. Recurrence rates in the ACF and NS groups were 11.9% (21 of 177) and 10.9% (18 of 165), respectively. No significant difference was evident between groups (pu2009=u20090.87). In addition, no significant difference in time to recurrence was seen between groups (pu2009=u20090.74). No serious adverse effects related to irrigation fluid were seen in either group. Regarding the irrigation fluid for CSDH surgery, no differences in recurrence rate or time to recurrence were seen between the ACF and NS groups. However, ACF offers sufficient safety as irrigation fluid for CSDH.


Journal of Neurosurgery | 2018

MGMT promoter methylation in patients with glioblastoma: is methylation-sensitive high-resolution melting superior to methylation-sensitive polymerase chain reaction assay?

Shinji Yamashita; Kiyotaka Yokogami; Fumitaka Matsumoto; Kiyotaka Saito; Asako Mizuguchi; Hajime Ohta; Hideo Takeshima

In BriefThe authors assessed MGMT promoter methylation results obtained by methylation-sensitive PCR (MS-PCR) and high-resolution melting (MS-HRM) methods to determine whether MS-HRM overcomes the limitations of MS-PCR. They found that MS-HRM was superior to MS-PCR for predicting survival outcome in 75 GBM patients with and without MGMT promoter methylation. Based on the results of multivariate Cox analysis, MS-HRM revealed independent prognostic factors. The authors suggest that MS-HRM is optimal for assessing the MGMT promoter methylation status and that it represents an alternative to MS-PCR.

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Shinichi Nakano

Memorial Hospital of South Bend

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Tomokazu Goya

Memorial Hospital of South Bend

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Izumi Nagata

Memorial Hospital of South Bend

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Ryogo Anei

Asahikawa Medical University

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