Akira Yamamoto

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (120)

  • Toshiki Dodo · Tomohisa Okada · Akira Yamamoto · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: This study aims to investigate difference between magnetization-prepared rapid gradient-echo imaging (MPRAGE) and spin-echo (SE) imaging for evaluating glioma on pre-contrast-enhanced (CE) and post-CE T1-weighted images at 3 T. Materials and methods: We retrospectively assessed pre-CE and post-CE T1-weighted images for tumor contrast in 64 consecutive glioma patients. Results: In the nonenhancing tumors, the contrast was significantly clearer in MPRAGE than SE. In the enhancing tumors, post-CE contrast ratio was significantly higher in SE than MPRAGE, but when subtraction images are evaluated, the difference got smaller. Conclusion: MPRAGE can be a good substitute of SE for T1-weighted imaging of glioma.
    Article · Aug 2016 · Clinical imaging
  • Eiichiro Okazaki · Akira Yamamoto · Norifumi Nishida · [...] · Yukio Miki
    [Show abstract] [Hide abstract] ABSTRACT: Objectives: The purpose of this study was to retrospectively evaluate the effectiveness of the model for end-stage liver disease (MELD) score compared with the Child-Pugh classification in patients who received 3-dimensional conformal radiotherapy (3D-CRT) for hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) by analyzing toxicity and prognostic factors. Methods: Fifty-six consecutive patients who had locally advanced HCC with PVTT treated by 3D-CRT between September 2007 and April 2013 were retrospectively reviewed. Results: The median survival time of all patients was 6.4 months. ROC analysis identified MELD score = 7.5 (area under the curve [AUC] 0.81) and Child-Pugh score = 6.5 (AUC 0.86) as the best cut-off values for predicting the incidence of complications over CTCAE Grade 2. There was no significant difference in the discrimination power between the MELD score and the Child-Pugh score comparing the two ROC curves (P = 0.17). On multivariate analysis, age, MELD score, and RT dose were significant prognostic factors for overall survival (P = 0.021, 0.038, and 0.006, respectively). In contrast, Child-Pugh classification, tumor response, PVTT response, and the number of prior interventional radiologic treatments were not significant on multivariate analysis. Conclusions: This study showed that the best MELD score cut-off value is 7.5, and that the MELD score is a better prognostic factor than the Child-Pugh classification in 3D-CRT for HCC with PVTT. Advances in knowledge: The MELD score is useful for predicting the risk of severe toxicities and the prognosis of patients treated with 3D-CRT for PVTT.
    Article · May 2016 · The British journal of radiology
  • Akira Yamamoto · Norifumi Nishida · Hiroyasu Morikawa · [...] · Yukio Miki
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: To investigate predictive factors and cutoff value of transient elastography (TE) measurements for assessing improvement in liver function after balloon-occluded retrograde transvenous obliteration (BRTO) for gastric varices (GV). Materials and methods: Retrospective analysis was performed of 50 consecutive patients followed for > 3 months after BRTO, who had undergone TE before BRTO between January 2011 and February 2015. The correlation between change in liver function (total bilirubin, albumin, and prothrombin time) and baseline liver function values and liver stiffness measurement (LSM) by TE was evaluated by Pearson correlation test. Receiver operating characteristic curves were used to determine cutoff values for discriminating between patients who had improved liver function and patients who did not. The time interval from BRTO to aggravation of esophageal varices (EV) (worsening morphology, development of new varices, or variceal rupture) grouped by cutoff values was also analyzed. Results: Serum albumin was significantly improved at 3 months after BRTO (3.57 g/dL vs 3.74 g/dL, P < .001). There was a significant negative correlation between change in albumin and baseline LSM (r = -0.50, P < .001). The best cutoff point for LSM was ≤ 22.9 kPa, with sensitivity and specificity of 78.4% and 69.2%, respectively, for predicting which patients would have improved albumin after BRTO. Among 33 patients, 29 (88%) patients had improved albumin. The 1-year progression rate of EV after BRTO was 13.6% in patients with LSM ≤ 22.9 kPa. Conclusions: The predictive factor for improvement in albumin after BRTO was lower LSM (≤ 22.9 kPa) using TE.
    Article · May 2016 · Journal of vascular and interventional radiology: JVIR
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    [Show abstract] [Hide abstract] ABSTRACT: Background and purpose: A thorough knowledge of fetal growth and development is key to understanding both the normal and abnormal fetal MR imaging findings. We investigated the size and signal intensity of the normal pituitary gland and the intrasphenoidal ossification around the Rathke pouch in formalin-fixed fetuses on MR imaging. Materials and methods: Thirty-two fetuses with undamaged brains were included in this study (mean age, 19.93 weeks; age range, 12-31 weeks). Visual inspection of the pituitary and ossification around the Rathke pouch in the sphenoid bone or the postsphenoid ossification was conducted. The extent of pituitary and postsphenoid ossification, pituitary/pons signal ratio, and postsphenoidal ossification/sphenoid bone signal ratio was compared according to gestational age. Results: The pituitary gland was identified as a hyperintense intrasellar structure in all cases, and postsphenoid ossification was identified as an intrasphenoidal hyperintense area in 27 of the 32 cases (84%). The mean pituitary/pons signal ratio was 1.13 ± 0.18 and correlated weakly with gestational age (R(2) = 0.243), while the mean postsphenoid ossification/sphenoid bone signal ratio was 2.14 ± 0.56 and did not show any increase with gestational age (R(2) = 0.05). No apparent change in the size of pituitary hyperintensity was seen with gestational age (R(2) = 0.001). Postsphenoid ossification showed an increase in size with gestational age (R(2) = 0.307). Conclusions: The fetal pituitary gland was hyperintense on T1-weighted images and the pituitary/pons ratio and extent of postsphenoid ossification correlated weakly with gestational age.
    Full-text Article · Apr 2016 · American Journal of Neuroradiology
  • [Show abstract] [Hide abstract] ABSTRACT: Purpose: To investigate changes in brain temperature according to the menstrual cycle in women using diffusion-weighted imaging (DWI) thermometry and to clarify relationships between brain and body temperatures. Materials and methods: In 20 healthy female volunteers (21.3-38.8 years), DWI of the brain was performed during the follicular and luteal phases to calculate the brain temperature. During DWI, body temperatures were also measured. Group comparisons of each temperature between the two phases were performed using the paired t test. Correlations between brain and body temperatures were analyzed using Pearson's correlation coefficient test. Results: Mean diffusion-based brain temperature was 36.24 °C (follicular) and 36.96 °C (luteal), showing a significant difference (P < 0.0001). Significant differences were also seen for each body temperature between the two phases. Correlation coefficients between diffusion-based brain and each body temperature were r = 0.2441 (P = 0.1291), -0.0332 (0.8387), and -0.0462 (0.7769), respectively. Conclusions: In women of childbearing age, brain and body temperatures appear significantly higher in the luteal than in the follicular phase. However, brain and body temperatures show no significant correlations.
    Article · Feb 2016 · Japanese journal of radiology
  • Hirofumi Yamada · Akira Yamamoto · Tomohisa Okada · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: To evaluate the impact of surgery on the optic pathway of patients with intra- or parasellar mass lesions, as evidenced by readout-segmented DTI. Materials and methods: Twenty-four patients with intra- or parasellar mass lesions were included in the study. Readout-segmented DTI and T2WI were obtained before and after surgery. The ROIs were set on the optic chiasm as well as the anterior and posterior optic tracts. For each ROI, axial diffusivity (AD), radial diffusivity (RD), fractional anisotropy (FA), and ADC values were calculated. DTI parameters in preoperative studies of all patients were compared and related to the presence of tumor compression. In patients who underwent surgery, pre- and postoperative DTI parameters were compared. The correlation between DTI parameters and visual function was determined. Results: In the preoperative studies, the optic chiasm of patients with tumor compression showed significant lower AD and RD values. The optic chiasm of patients with visual field disorder showed significantly lower AD and RD values compared to patients without the disorder. There was a negative correlation with a trend toward significance between FA values and visual field disorder scores. The comparative analysis of patients in pre- and postoperative studies showed that the optic chiasm of patients with tumor compression presented a significant lower FA (0.41 versus 0.30, p = 0.0068) and higher RD values after surgery. Conclusions: DTI is a useful tool to assess the impact of surgery on the optic chiasm and nerve.
    Article · Jan 2016 · Magnetic Resonance Imaging
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    Thai Akasaka · Koji Fujimoto · Takayuki Yamamoto · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: In Compressed Sensing (CS) of MRI, optimization of the regularization parameters is not a trivial task. We aimed to establish a method that could determine the optimal weights for regularization parameters in CS of time-of-flight MR angiography (TOF-MRA) by comparing various image metrics with radiologists' visual evaluation. TOF-MRA of a healthy volunteer was scanned using a 3T-MR system. Images were reconstructed by CS from retrospectively under-sampled data by varying the weights for the L1 norm of wavelet coefficients and that of total variation. The reconstructed images were evaluated both quantitatively by statistical image metrics including structural similarity (SSIM), scale invariant feature transform (SIFT) and contrast-to-noise ratio (CNR), and qualitatively by radiologists' scoring. The results of quantitative metrics and qualitative scorings were compared. SSIM and SIFT in conjunction with brain masks and CNR of artery-to-parenchyma correlated very well with radiologists' visual evaluation. By carefully selecting a region to measure, we have shown that statistical image metrics can reflect radiologists' visual evaluation, thus enabling an appropriate optimization of regularization parameters for CS.
    Full-text Article · Jan 2016 · PLoS ONE
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    Dataset: S1 Fig
    Thai Akasaka · Koji Fujimoto · Takayuki Yamamoto · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: A color plot and top 10 list of the average slice-by-slice NMSE values between the SoS and reconstructed images. The image to the left is a color plot of the average slice-by-slice NMSE values between the SoS and reconstructed images. The axes are the same as in Fig 6; the vertical axis is α (1.0 × 10−7 to 3.2 × 10−3 from top to bottom) and the horizontal axis is β (1.0 × 10−7 to 3.2 × 10−3 from left to right). Notice the dissimilarity with the result of visual evaluation (Fig 4). (TIF)
    Full-text Dataset · Jan 2016
  • Akira Yamamoto · Tomohisa Okada · Jun C. Takahashi
    [Show abstract] [Hide abstract] ABSTRACT: Moyamoya is a disease affecting the cerebral arteries, which predisposes individuals to recurrent ischemic attack in association with progressive steno-occlusive change of the intracranial internal carotid arteries and their proximal branches. The disorder is typically characterized by a reduction in blood flow in the major vessels of the anterior circulation of the brain. This results in the development of a compensatory collateral vasculature around the stenosed vessels, near the apex of the internal carotid, on the cortical surface, leptomeninges, and branches of the external carotid artery and the base of the skull. In advanced cases, the posterior circulation is also involved, including the basilar and posterior cerebral arteries. While it was first described as a “hypoplasia of the bilateral internal carotid arteries,” the characteristic appearance of the network of abnormally dilated collateral vessels on conventional angiography was compared to “a puff of cigarette smoke” (Arch Neurol 20(3):288–899, 1969) or “moyamoya” in Japanese. The designation “spontaneous occlusion of the circle of Willis” was recently suggested as an alternative by the International Classification of Diseases (ICD). Moyamoya disease patients are predominantly found in Eastern Asian countries such as Japan and the Republic of Korea. Moyamoya disease patients show bimodal distribution, adult type and pediatric type. Symptom of adult moyamoya patients can be either ischemic or hemorrhagic; nevertheless, pediatric patients usually present with ischemia. In ischemic moyamoya disease, the therapeutic effect of surgical revascularization (extracranial-intracranial bypass) has been well established. Bypass surgery can improve the impaired cerebral hemodynamic state and decrease the recurrent ischemic events. Management of the hemorrhagic moyamoya disease, on the other hand, presents a serious challenge. Despite the extremely high rate of rebleeding attacks, no therapeutic method has been established until recently. In 2013, the Japan Adult Moyamoya (JAM) Trial, a multicentered prospective randomized controlled trial, was completed. It has been revealed that bypass surgery significantly decreases the rate of rebleeding attacks and improve the patients’ prognosis during the following 5 years. This epoch-making study is expected to establish a guiding principle for the treatment of hemorrhagic moyamoya disease.
    Chapter · Jan 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Objectives: The aims of this study were to optimize parameters for Nesterov algorithm (NESTA) in reconstruction of 3-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) at 3 T by performing an exhaustive search and to validate the performance of compressed sensing (CS) by applying it to data from cerebral aneurysms and evaluating diagnostic quality. Materials and methods: Three-dimensional TOF-MRA was obtained using a 3 T MR system with a 32-channel head coil for both healthy volunteers and 10 patients (11 aneurysms). No undersampling was applied for imaging parameters, including parallel imaging or other partial Fourier sampling. In the first step, the experimental setup was for healthy subjects to optimize CS parameters of NESTA and the undersampling mask pattern, so 24,696 different reconstruction conditions were surveyed for sampling rates of 8.0X and 5.0X. Mean square error (MSE) was calculated for each image reconstructed with the undersampling pattern and CS parameter sets. Evaluation was by normalized MSE, edge sharpness for MRA reconstructed using fully sampled data (MRA-full), zero-filled MRA (ZF-MRA) with Poisson disk undersampling mask, and CS-MRA (5.0X and 8.0X) with iterations of 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50. CS-MRA (5.0X and 8.0X) with 5, 10, and 50 iterations of the sampling pattern and CS parameter set with the lowest MSE were visually inspected by 2 neuroradiologists to check the diagnostic quality. Results: The sampling pattern and CS parameter set with the lowest MSE were identical for both CS-MRA 5.0X and CS-MRA 8.0X. At the initial 5 to 15 iterations, MSE of both sampling rates greatly decreased from that of ZF-MRA. For subsequent iterations, the decrease in MSE was relatively small. For CS-MRA, sharpness greatly increased from that of ZF-MRA within the initial 5 to 15 iterations, followed by slight increases with further iterations. Two neuroradiologists graded most aneurysms as excellent, with the exception of 1 to 4 aneurysms recognized as good by 1 observer in CS-MRA (8.0X). Conclusions: Optimization of NESTA in the reconstruction of 3-dimensional TOF-MRA was conducted, and the parameters and undersampling mask with the lowest MSE were determined. Caliber measurement should be performed with CS (5.0X) with 25 or 30 iterations. Most cerebral aneurysms were sufficiently recognized using CS-MRA (5.0X) or CS-MRA (8.0X) with 10 iterations.
    Article · Nov 2015 · Investigative radiology
  • Shigeaki Umeoka · Akira Yamamoto · Koji Sakai · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: PURPOSE 1.To investigate the feasibility and utility of DKI for the assessment of uterine endometrial cancer 2.To correlate ADC, D and K values with histologic subtypes of endometrial lesion CONCLUSION DKI seems an effective, non-invasive method for the assessment of endometrial lesions. ALL D-, K-, and ADC-values are helpful for the differentiation between benign and malignant endometrial lesion. Only the K-value shows an excellent correlation with histological subtypes of uterine endometrial cancer, and may serve as a new, useful prognostic biomarker.
    Conference Paper · Nov 2015
  • Noah Nakanishi · Taro Shimono · Akira Yamamoto · Yukio Miki
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: Delayed colonic perforation after acute pancreatitis (AP) is a potentially lethal complication. This study investigated the frequency and predictors of delayed colonic perforation (DCP) following AP by reviewing the earliest laboratory data and computed tomography (CT) examination findings after pancreatitis onset. Materials and methods: This retrospective study examined 75 consecutive cases of AP treated between April 2009 and April 2014. Laboratory data after onset and imaging features from earliest CT examinations (Balthazar grade, CT Severity Index) were reviewed. To clarify relationships between these data and DCP, univariate analyses were undertaken between perforated and nonperforated groups. Results: Delayed colonic perforation occurred in four of the 75 patients (5.3 %). Median duration to perforation after onset was 13 days (range 6-47). All four patients with DCP showed grade E according to Balthazar grade (≥2 peripancreatic collections and/or gas bubbles in or adjacent to pancreas). Univariate analyses identified Balthazar grade E as a risk factor for DCP (p = 0.0087). Conclusion: Delayed colonic perforation is not uncommon and can occur a week or more after AP. Balthazar grade E on earliest CT after onset represents a risk factor for DCP.
    Article · Oct 2015 · Japanese journal of radiology
  • [Show abstract] [Hide abstract] ABSTRACT: Background: Focal stenosis or occlusion of the infrarenal aorta is rare, and treatment is usually conventional bypass or endarterectomy. However, endovascular treatment has advanced in recent years. The purpose of this retrospective study is to report the results of primary stenting for focal infrarenal aortic occlusive disease and clarify the usefulness of endovascular treatment. Methods: This study includes 6 consecutive patients (3 men, 3 women; mean age, 59.3 years) with infrarenal aortic stenosis or occlusion who underwent endovascular intervention at our hospital between April 2009 and February 2014. All patients had bilateral intermittent claudication. The mean preoperative ankle-brachial index (ABI) showed a slight to moderate decrease: right 0.668 and left 0.636. The mean lesion site length was 12.5 mm, the percent stenosis was 90.7%, and calcification was present in 3 patients. Primary stenting was performed in all patients. The stent selected was generally a self-expanding stent (SES). For patients with severe calcification, the stent selected was a balloon-expandable stent (BES). Results: Four patients received an SES and two patients received a BES. The technical success rate was 100%, no complications occurred, and the mean pressure gradient disappeared or decreased. Symptoms resolved in all patients and the postoperative ABI improved: right 0.923 and left 0.968. During a mean follow-up period of 27 months, there were no recurrent symptoms and no restenosis on CT angiography. Conclusions: Endovascular treatment should be considered as a first line treatment for focal infrarenal aortic stenosis and occlusion.
    Article · Oct 2015 · Osaka city medical journal
  • [Show abstract] [Hide abstract] ABSTRACT: There is no established second-line treatment for steroid-resistant acute graft-versus-host disease (GVHD). We prospectively assessed the safety and efficacy of intra-arterial steroid infusions (IASI) for steroid-resistant acute gastrointestinal (GI) GVHD and compared the outcomes with those of historical controls at our institution. Nineteen consecutive, allogeneic hematopoietic stem cell transplantation subjects aged 31-67 years (median 52) were enrolled between October 2008 and November 2012. Acute GVHD was confirmed by biopsy in all cases. The enrolled patients were treated with infusions of methylprednisolone into the mesenteric arteries and/or gastroduodenal and left gastric arteries. Fourteen consecutive patients who developed steroid-resistant acute GI GVHD between 2001 and 2008 were used as controls. For the primary endpoint at day 28, the overall and complete responses in the IASI group trended higher (79% vs. 42%, p=.066) and were significantly higher (63% vs. 21%, p=.033) than those in the control group. Although not statistically significant due to the small population, the crude day 180-non-relapse mortality rate was about 20 percent lower and the day 180-overall survival rate tended to be higher than the control (11% versus 29%, p=.222; 79% versus 50%, p=.109, respectively). There were no serious IASI-related complications. Our results suggest that IASI can safely provide excellent efficacy for refractory acute GI GVHD without increasing infection-related complications and may improve prognosis. Copyright © 2015 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.
    Article · Aug 2015 · Experimental hematology
  • Gosuke Okubo · Tomohisa Okada · Akira Yamamoto · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: To compare magnetization-prepared two rapid acquisition gradient echoes (MP2RAGE) imaging with conventional MPRAGE imaging for deep gray matter (GM) segmentation, reproducibility, contrast ratio (CR) and contrast-to-noise ratio (CNR), and to evaluate reproducibility of T1 maps derived from MP2RAGE. MP2RAGE and MPRAGE imaging were conducted twice for each of 20 volunteers on a 3 Tesla MRI scanner. Images were normalized and segmented using SPM12 with the DARTEL algorithm. Reproducibility of segmentation was evaluated using coefficients of variation (COVs) of deep GM probability maps between first and second scans, which was compared between MP2RAGE and MPRAGE. Differences in deep GM probability were compared voxel-wise. CR and CNR analyses were conducted using regions of interest. COVs of T1 maps were also evaluated. Comparison of GM probability maps demonstrated that putamen, caudate nucleus and thalamus were segmented significantly larger in MP2RAGE than in MPRAGE, and MP2RAGE was inferior only at some areas of globus pallidus and lateral thalamus (P < 0.05; false discovery rate, FDR). CRs of deep GM structures were significantly better in MP2RAGE (P < 0.0001). COVs of deep GM probability maps were significantly higher at large areas of the deep GM in MPRAGE (P < 0.05, FDR). COVs ranged from 0.50 to 3.31% in MP2RAGE and from 0.62 to 4.12% in MPRAGE. COVs of the T1 map were around 2%. MP2RAGE yields greater reproducibility and better tissue contrast than MPRAGE in deep GM. T1 maps derived from MP2RAGE were highly reliable. MP2RAGE is useful for measurement and analysis of deep GM.J. Magn. Reson. Imaging 2015. © 2015 Wiley Periodicals, Inc.
    Article · Jun 2015 · Journal of Magnetic Resonance Imaging
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    [Show abstract] [Hide abstract] ABSTRACT: The aim of this study was to assess the consistency and reproducibility of quantitative susceptibility mapping (QSM) at 3-T and 1.5-T magnetic resonance (MR) scanners. This study was approved by institutional ethics committee, and written informed consent was obtained. Twenty-two healthy volunteers underwent 2 examinations on different days. Each examination consisted of MR imaging on both 3-T and 1.5-T MR scanners. The data from both scanners and examination days were obtained, and QSM was calculated with STI Suite using 2 different algorithms-harmonic phase removal using laplacian operator (HARPERELLA) and a sophisticated harmonic artifact reduction for phase data (SHARP) method with a variable radius of the spherical kernel at the brain boundary (V-SHARP). We evaluated consistency of QSM between 3 T and 1.5 T and the reproducibility between the first and second examinations using 2-phase processing methods (HARPERELLA and V-SHARP). Susceptibility values of regions of interests at 3 T were highly correlated with those at 1.5 T with good agreement (HARPERELLA, R = 0.838; V-SHARP, R = 0.898) (average difference, ±1.96 SD; HARPERELLA, -0.012 ± 0.046; V-SHARP, -0.002 ± 0.034). Reproducibility analysis demonstrated excellent correlation between the first and second examination at both 3 T and 1.5 T for both algorithms (HARPERELLA at 3 T, R = 0.921; 1.5 T, R = 0.891; V-SHARP at 3 T, R = 0.937; 1.5 T, R = 0.926). Bland-Altman analysis showed excellent reproducibility for HARPERELLA (3 T, -0.003 ± 0.032; 1.5 T, -0.003 ± 0.038) and V-SHARP (3 T, -0.003 ± 0.027; 1.5 T, -0.003 ± 0.029). Susceptibility values of these 2 algorithms were highly correlated with good agreement (3T, R = 0.961; 1.5 T, R = 0.931) (3 T, 0.009 ± 0.023; 1.5 T, -0.003 ± 0.049). Quantitative susceptibility mapping with HARPERELLA and V-SHARP demonstrated good reproducibility at 3 T and 1.5 T, and QSM with V-SHARP demonstrated good consistency at 3 T and 1.5 T.
    Full-text Article · Apr 2015 · Investigative radiology
  • [Show abstract] [Hide abstract] ABSTRACT: Pancreatic cancer (PC) with arterial invasion is currently a contraindication to resection and has a miserable prognosis. Seventeen patients with locally advanced PC involving the celiac axis and/or common hepatic artery (CHA) who received chemoradiotherapy (CRT) composed of gemcitabine, S-1, and external beam irradiation over the last 2 years were investigated. Thirteen patients underwent pancreatectomy with major arterial resection: 6 distal pancreatectomies with resection of the celiac axis, 4 total pancreatectomies with resection of both the celiac axis and the CHA, and 3 pancreatoduodenectomies with resection of the CHA. Preoperative arterial embolization and/or arterial reconstruction to prevent ischemic gastropathy and hepatopathy was performed in 7 of the 13 patients. Distant metastases were found in 3 patients after CRT. One patient did not consent to operation after CRT. The morbidity rate of the 13 patients who underwent surgery was 62% (8/13), but no deaths occurred. Although there were no responders on CT, >90% of tumor cells were necrotic on histopathology in 5 of 13 tumors after CRT. Invasion of the celiac axis remained in 5 tumors, and extrapancreatic plexus invasion remained in 8 tumors, but an R0 resection was achieved in 12 of 13 tumors. Lymph node metastases were found in 3 of 13 cases. The overall 1-year survival rate from commencement of CRT and resection was 12 of 13 patients. Neoadjuvant CRT containing gemcitabine and S-1 and subsequent pancreatectomy with major arterial resection for patients with locally advanced PC with arterial invasion were carried out safely with an acceptable R0 resection acceptable morbidity and mortality, and encouraging survival (12 of 13) at 1 year postoperatively. Copyright © 2015 Elsevier Inc. All rights reserved.
    Article · Apr 2015 · Surgery
  • [Show abstract] [Hide abstract] ABSTRACT: To evaluate prevalence of subcutaneous fluid collection (SFC) in infectious thoracolumbar spondylodiscitis (SD) compared with control patients and to investigate correlation between volume changes of SFC and treatment response of SD. This retrospective study was approved by our institutional review board. From April 2011 to March 2012, 49 patients (24 SD and 25 non-SD patients) were enrolled. Prevalence of SFC was evaluated respectively for SD and non-SD patients using magnetic resonance imaging (MRI) on the sagittal short tau inversion recovery (STIR) imaging or fat-saturated T2-weighted imaging (T2WI), and compared. In SD patients with SFC, correlation was investigated between SFC volume on the 1st MRI and initial clinical status. The same analysis was conducted also for SFC volume changes from the 1st to 2nd or last MRI. SFC was found in 20 patients with SD (83.3%) and 3 non-SD patients (12%) with significant difference (p<.001). In 20 SD patients with SFC, 17 patients had follow-up MRI. For the 1st MRI, no significant correlation was found between volume of SFC and initial status of patients, including body weight, body mass index (BMI), white blood cell (WBC), and erythrocyte sedimentation rate (ESR). However, significant positive correlations were found between changes of C-reactive protein (CRP) and SFC volume from the 1st to 2nd as well as from the 1st to the last MRI (each p<.05). SD patients had significantly higher prevalence of SFC than non-SD patients. Volume changes of SFC had significant correlation with changes of CRP, which can be used as an imaging marker for treatment response of SD on MRI. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Article · Apr 2015 · European Journal of Radiology
  • Hironori Sunakawa · Daisuke Tokuhara · Akira Yamamoto · [...] · Haruo Shintaku
    [Show abstract] [Hide abstract] ABSTRACT: There is no consensus guidelines for treating duodenal variceal bleeding, which is a rare and life-threatening complication of portal hypertension. Here we report an exceedingly unusual case in a 9-year-old boy who had developed left-sided portal hypertension after surgical treatment for pancreatoblastoma followed by a duodenal variceal bleeding with massive melena, severe anemia (hemoglobin 4.5 g/dL) and hypovolemic shock. Emergency partial splenic arterial embolization (PSE) provided a reduction of variceal bleeding and improved blood pressure. Endoscopic injection sclerotherapy (EIS) was subsequently performed and stopped the duodenal variceal bleeding without the complication of portal vein thrombosis caused by injected sclerosant under hepatopetal flow. Our case demonstrates that emergency combined therapy with PSE and EIS can be considered as the therapeutic option for the management of left-sided portal hypertension-induced ectopic variceal bleedings in order to avoid the complication of portal embolization by EIS and provide effective hematostasis.
    Article · Apr 2015 · Clinical Journal of Gastroenterology
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    Akihiko Sakata · Tomohisa Okada · Akira Yamamoto · [...] · Kaori Togashi
    [Show abstract] [Hide abstract] ABSTRACT: Background. Previous studies have shown that intratumoral hemorrhage is a common finding in glioblastoma multi-forme, but is rarely observed in primary central nervous system lymphoma. Our aim was to reevaluate whether intratumoral hemorrhage observed on T2-weighted imaging (T2WI) as gross intratumoral hemorrhage and on susceptibility-weighted imaging as intratumoral susceptibility signal can differentiate primary central nervous system lymphoma from glioblastoma multiforme. Patients and methods. A retrospective cohort of brain tumors from August 2008 to March 2013 was searched, and 58 patients (19 with primary central nervous system lymphoma, 39 with glioblastoma multiforme) satisfied the inclusion criteria. Absence of gross intratumoral hemorrhage was examined on T2WI, and an intratumoral susceptibility signal was graded using a 3-point scale on susceptibility-weighted imaging. Results were compared between primary central nervous system lymphoma and glioblastoma multiforme, and values of P < 0.05 were considered significant. Results. Gross intratumoral hemorrhage on T2WI was absent in 15 patients (79%) with primary central nervous system lymphoma and 23 patients (59%) with glioblastoma multiforme. Absence of gross intratumoral hemorrhage could not differentiate between the two disorders (P = 0.20). However, intratumoral susceptibility signal grade 1 or 2 was diagnostic of primary central nervous system lymphoma with 78.9% sensitivity and 66.7% specificity (P < 0.001), irrespective of gross intratumoral hemorrhage. Conclusions. Low intratumoral susceptibility signal grades can differentiate primary central nervous system lymphoma from glioblastoma multiforme. However, specificity in this study was relatively low, and primary central nervous system lymphoma cannot be excluded based solely on the presence of an intratumoral susceptibility signal.
    Full-text Article · Mar 2015 · Radiology and Oncology