Akira Yamamoto

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (99)181.35 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose was to compare capability of fluorine-18 fluorodeoxyglucose (FDG)-PET and thallium-201 (Tl)-SPECT for grading meningioma.This retrospective study was conducted as a case-control study under approval by the institutional review board. In the hospital information system, 67 patients (22 men and 45 women) who had both FDG-PET and Tl-SPECT preoperative examinations were found with histopathologic diagnosis of meningioma. The maximum FDG uptake values of the tumors were measured, and they were standardized to the whole body (SUVmax) and normalized as gray matter ratio (SUVRmax). Mean and maximum Tl uptake ratios (TURmean and TURmax, respectively) of the tumors were measured and normalized as ratios to those of the contralateral normal brain. Receiver-operating characteristic curve analyses of the 4 indexes were conducted for differentiation between low- and high-grade meningiomas, and areas under the curves (AUCs) were compared. Correlation coefficients were calculated between these indexes and Ki-67.Fifty-six meningiomas were classified as grade I (low grade), and 11 were grade II or III (high grade). In all 4 indexes, a significant difference was observed between low- and high-grade meningiomas (P < 0.05). AUCs were 0.817 (SUVmax), 0.781 (SUVRmax), 0.810 (TURmean), and 0.831 (TURmax), and no significant difference was observed among the indexes. Their sensitivity and specificity were 72.7% to 90.9% and 71.4% to 87.5%, respectively. Correlation of the 4 indexes to Ki-67 was statistically significant, but coefficients were relatively low (0.273-0.355).Tl-SPECT, which can be used at hospitals without a cyclotron or an FDG distribution network, has high diagnostic capability of meningioma grades comparable to FDG-PET.
    Medicine. 02/2015; 94(6):e549.
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    ABSTRACT: Amide proton transfer (APT) magnetic resonance imaging is gaining attention for its capability for grading glial tumors. Usually, a representative slice is analyzed. Different definitions of tumor areas have been employed in previous studies. We hypothesized that the accuracy of APT imaging for brain tumor grading may depend upon the analytical methodology used, such as selection of regions of interest (ROIs), single or multiple tumor slices, and whether or not there is normalization to the contralateral white matter. This study was approved by the institutional review board, and written informed consent was waived. Twenty-six patients with histologically proven glial tumors underwent preoperative APT imaging with a three-dimensional gradient-echo sequence. Two neuroradiologists independently analyzed APT asymmetry (APTasym) images by placing ROIs on both a single representative slice (RS) and all slices including tumor (i.e. whole tumor: WT). ROIs indicating tumor extent were separately defined on both FLAIR and, if applicable, contrast-enhanced T1-weighted images (CE-T1WI), yielding four mean APTasym values (RS-FLAIR, WT-FLAIR, RS-CE-T1WI, and WT-CE-T1WI). The maximum values were also measured using small ROIs, and their differences among grades were evaluated. Receiver operating characteristic (ROC) curve analysis was also conducted on mean and maximum values. Intra-class correlation coefficients for inter-observer agreement were excellent. Significant differences were observed between high- and low-grade gliomas for all five methods (P < 0.01). ROC curve analysis found no statistically significant difference among them. This study clarifies that single-slice APT analysis is robust despite tumor heterogeneity, and can grade glial tumors with or without the use of contrast material.
    Journal of Neuro-Oncology 01/2015; · 3.12 Impact Factor
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    ABSTRACT: The objective was to evaluate diagnostic performance of dynamic susceptibility-contrast perfusion-weighted imaging, diffusion-weighted imaging, and (18)F-fluorodeoxyglucose positron emission tomography in differentiating primary central nervous system lymphoma (PCNSL) and glioblastoma. Twenty-three glioblastomas and 11 PCNSLs were analyzed with uncorrected cerebral blood volume (CBV) ratio, fifth percentile value of cumulative apparent diffusion coefficient histogram (ADC5%), and maximum standardized uptake value (SUVmax) using regions of interest created semiautomatically on enhancing areas. Uncorrected CBV ratio was highly capable of differentiating PCNSL from glioblastoma, as well as SUVmax and ADC5%. Uncorrected CBV ratio demonstrates high diagnostic performance comparable to SUVmax. Copyright © 2014 Elsevier Inc. All rights reserved.
    Clinical Imaging 12/2014; · 0.60 Impact Factor
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    ABSTRACT: We present a case series of a palliative radiofrequency ablation (RFA) for the tumors that lead to the resolution of pain and motor function disorders. RFA is widely used on tumors in various organs and often reported in good outcome. There are some reports that RFA was performed as a palliative treatment but a few reports of RFA that performed for lung tumor as a palliative treatment. This case series includes two cases, palliative RFA for a sacrum and a lung tumor. The results of this case series presented that a palliative RFA is effective in improving the symptoms of patients.
    BMC Research Notes 10/2014; 7(1):765.
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    ABSTRACT: To evaluate whether the combination of radiofrequency (RF) ablation and local injection of the immunostimulant Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces systemic antitumor immunity. Japanese White rabbits with lung and auricle VX2 tumors were randomized into three groups: control (n = 8; no treatment), RF ablation only (n = 8; RF ablation to the lung tumor), and RF ablation with local BCG injection into the lung tumor (n = 8). Treatments were performed 1 week after tumor implantation. Survival was evaluated with Kaplan-Meier method and log-rank test. Weekly mean volume and specific growth rate (SGR) of auricle tumors were calculated, and comparisons were made by Mann-Whitney test. Median survival of control, RF-only, and RF/BCG groups were 23, 41.5, and 103.5 days, respectively. Survival was significantly prolonged in the RF-only and RF/BCG groups compared with the control group (P = .034 and P =.003, respectively), but no significant difference was found between the RF-only and RF/BCG groups (P = .279). Only in the RF/BCG group was mean auricle tumor volume decreased 5 weeks after implantation. No significant difference in SGR was found between the control and RF-only groups (P = .959), but SGR in the RF/BCG group was significantly lower than in the control group (P = .005). The combination of RF ablation and local injection of BCG resulted in distant tumor suppression compared with the control group, whereas RF ablation alone did not produce this effect. Therefore, the combination of RF ablation and local injection of BCG may induce systemic antitumor immunity. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.
    Journal of vascular and interventional radiology: JVIR 10/2014; · 1.81 Impact Factor
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    ABSTRACT: The aim of this study is to investigate the relationship between abnormal retropharyngeal lymph nodes (RPLNs) and sinonasal malignancies among adults.
    Neuroradiology 09/2014; · 2.37 Impact Factor
  • International Congress of Radiology ICR2014, Dubai, UAE; 09/2014
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    ABSTRACT: To evaluate the feasibility of gastric variceal (GV) volumetry using computed tomography (CT) images taken before balloon-occluded retrograde transvenous obliteration (B-RTO) and to assess its correlation with the actual amount of 5% ethanolamine oleate and iodinated contrast medium (EOI) injected in B-RTO. Forty-seven consecutive patients with GV underwent B-RTO of the gastrorenal shunt. GV volume was measured with preoperative CT images by three radiologists. Statistical significance was examined by intraclass correlation coefficient (ICC) for concordance among three radiologists and by Pearson correlation test for correlation between GV volume and the amount of 5% EOI injected. GV volumes measured by three radiologists significantly correlated with each other (ICC=0.959). Combining all patients and all measurements, the mean GV volume and the mean amount of 5% EOI were 27.02±16.67cm3 and 28.72±17.72mL, respectively. There was a significant correlation between GV volume, calculated as a mean of the three values measured by the three radiologists, and the amount of EOI (r2=0.706, p<0.001). GV volume measured on CT showed a significant correlation with the amount of 5% EOI injected. CT volumetry of GV has the potential to determine an amount of the sclerosing agent to be injected in B-RTO.
    Hepato-gastroenterology 09/2014; 61(134):1806-11. · 0.91 Impact Factor
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    ABSTRACT: Objective: We qualitatively evaluated the differences among susceptibility-weighted (SWI), magnitude (MAG), and high pass filtered phase (PHA) images in depicting inter-lobar differences in the appearance of the signal of the corticomedullary junction (CMJ). We conducted quantitative evaluation to validate the qualitative results. Materials and Methods: We obtained SWI images from 25 preoperative brain tumor patients (12 men, 13 women, aged 19 to 82 years, mean, 52 years). Two trained neuro-radiologists evaluated MAG, PHA, and SWI images. Qualitative evaluation of the CMJ signal and quantitative calculation of the relative signal ratio (RSR) percentages between the CMJ and deep white matter (WM) were conducted at 3 different slice levels of the brain independently for 4 different lobes (frontal, parietal, temporal, and occipital) and com-pared among MAG, PHA, and SWI. The extent of the area of the CMJ signal was graded on a 4-point scale (Grade 3, >75%; Grade 2, 50 to 75%; Grade 1, 25 to 50%; Grade 0, <25%). Data were statistically analyzed using a nonparametric Friedman test. Results: The Kappa coefficients between the qualitative and quantitative grades were 0.002 for MAG, 0.0047 for PHA, and 0.050 for SWI. Qualitatively, on the PHA images and SWI, grades of the occipital lobes were significantly higher than those of the other lobes (P < 0.005). Quantitatively, PHA images showed statistically significant interlobar differences in RSR percentage values of the CMJ (P = 0.025). Conclusion: Qualitatively, the appearance of the CMJ differed significantly among the different lobes of the brain on SWI and underlying PHA images but not on MAG images. Quantitatively, only PHA images showed significant interlobar differences in the RSR. PHA images are most sensitive to the CMJ signal contrast due to local paramagnetic iron content.
    Magnetic Resonance in Medical Sciences 08/2014; · 1.04 Impact Factor
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    ABSTRACT: To evaluate the validity of 3D dynamic pituitary MR imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), with special emphasis on demarcation of pituitary posterior lobe and stalk.
    European Journal of Radiology 07/2014; · 2.16 Impact Factor
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    ABSTRACT: Oxygen causes an increase in the longitudinal relaxation rate of tissues through its T1-shortening effect owing to its paramagnetic properties. Due to such effects, MRI has been used to study oxygen-related signal intensity changes in various body parts including cerebrospinal fluid (CSF) space. Oxygen enhancement of CSF has been mainly studied using MRI sequences with relatively longer time resolution such as FLAIR, and T1 value calculation. In this study, fifteen healthy volunteers were scanned using fast advanced spin echo MRI sequence with and without inversion recovery pulse in order to dynamically track oxygen enhancement of CSF. We also focused on the differences of oxygen enhancement at sulcal and ventricular CSF. Our results revealed that CSF signal after administration of oxygen shows rapid signal increase in both sulcal CSF and ventricular CSF on both sequences, with statistically significant predominant increase in sulcal CSF compared with ventricular CSF. CSF is traditionally thought to mainly form from the choroid plexus in the ventricles and is absorbed at the arachnoid villi, however, it is also believed that cerebral arterioles contribute to the production and absorption of CSF, and controversy remains in terms of the precise mechanism. Our results demonstrated rapid oxygen enhancement in sulcal CSF, which may suggest inhaled oxygen may diffuse into sulcal CSF space rapidly probably due to the abundance of pial arterioles on the brain sulci.
    PLoS ONE 06/2014; 9(6):e100723. · 3.53 Impact Factor
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: To optimize visualization of lenticulostriate artery (LSA) by time-of-flight (TOF) magnetic resonance angiography (MRA) with slice-selective off-resonance sinc (SORS) saturation transfer contrast pulses and to compare capability of optimal TOF-MRA and flow-sensitive black-blood (FSBB) MRA to visualize the LSA at 3T. This study was approved by the local ethics committee, and written informed consent was obtained from all the subjects. TOF-MRA was optimized in 20 subjects by comparing SORS pulses of different flip angles: 0, 400°, and 750°. Numbers of LSAs were counted. The optimal TOF-MRA was compared to FSBB-MRA in 21 subjects. Images were evaluated by the numbers and length of visualized LSAs. LSAs were significantly more visualized in TOF-MRA with SORS pulses of 400° than others (P < .003). When the optimal TOF-MRA was compared to FSBB-MRA, the visualization of LSA using FSBB (mean branch numbers 11.1, 95% confidence interval (CI) 10.0-12.1; mean total length 236 mm, 95% CI 210-263 mm) was significantly better than using TOF (4.7, 95% CI 4.1-5.3; 78 mm, 95% CI 67-89 mm) for both numbers and length of the LSA (P < .0001). LSA visualization was best with 400° SORS pulses for TOF-MRA but FSBB-MRA was better than TOF-MRA, which indicates its clinical potential to investigate the LSA on a 3T magnetic resonance imaging.
    Academic radiology 06/2014; 21(6):812-6. · 2.09 Impact Factor
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    ABSTRACT: To investigate the diffusion tensor imaging parameters of the optic radiation and surrounding structures using the high-resolution readout-segmented diffusion tensor imaging method. Coronal readout-segmented diffusion tensor images were acquired in 15 healthy volunteers. On three slices of each image, eigenvalue 1, fractional anisotropy, radial diffusivity, apparent diffusion coefficient, and signal intensity on T2-weighted images were measured in the lateral inferior longitudinal fasciculus, external and internal layers of the optic radiation, and the tapetum within regions of interest delineated by two independent observers. Profile curve analysis of regions of interest across the optic radiation and surrounding structures was performed for a representative typical case. Significant differences in fractional anisotropy, radial diffusivity and apparent diffusion coefficient were observed between external and internal layers of the optic radiation, while there was no significant difference in eigenvalue 1. In fractional anisotropy maps, two low signal bands were observed between the inferior longitudinal fasciculus, the optic radiation and the tapetum. Profile curve analysis showed a minimum on the fractional anisotropy and eigenvalue 1 images and a maximum in the radial diffusivity image. Readout-segmented diffusion tensor imaging revealed significant differences in the diffusion tensor imaging parameters between internal and external layers of the optic radiation.
    Anatomia Clinica 04/2014; · 1.33 Impact Factor
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    ABSTRACT: To examine differences in neointimal hyperplasia (NIH) after placing a self-expanding (SE) stent across size-discrepant vessels. The subjects were 6 beagles, and the target vessels were the abdominal aorta and the external iliac artery (EIA). A nitinol SE stent was placed which was normal-sized in the aorta and oversized in the EIA. Angiography and intravascular ultrasound (IVUS) were performed immediately and after 1 and 3 months; histopathologic examinations were then performed. Furthermore, the chronic outward force (COF) on the same type of stent was investigated in vitro. On IVUS, thickened intima was seen on the EIA at 1 month (5.1 ± 4.2 mm(2)) and at 3 months (7.8 ± 2.5 mm(2)). For the aorta, thickening of the intima was negligible at any time. Histopathologically, the percentage of the vessel obliterated by NIH was significantly greater on the iliac side than on the aortic side (33.2 ± 10.4 vs. 13.4 ± 4.4 %). The COF exerted when stent diameter reached that of the EIA and the aorta was 0.73 and 0.17 N/mm(2), respectively. When a non-tapered stent is placed in vessels with a large discrepancy in diameter, attention must be paid to increased NIH in the oversized side.
    Japanese journal of radiology 04/2014; 32(6). · 0.73 Impact Factor
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    ABSTRACT: Quantitative values of CT attenuation, apparent diffusion coefficient (ADC), and standardized uptake value (SUV) were investigated for differentiation between pineal parenchymal tumors (PPTs) and germinomas. Differences in age, sex, and calcification pattern were also evaluated. Twenty-three patients with PPTs and germinomas in 20 years were retrospectively enrolled under the approval of the institutional review board. CT attenuation, ADC, and SUV (20, 13, and 10 patients, respectively) were statistically compared between the two tumors. Differences in sex and patterns of calcification ("exploded" or "engulfed") were also examined. Mean patient ages were compared among three groups of pineoblastoma, pineal parenchymal tumor of intermediate differentiation, (PPTID) and pineocytoma and germinoma. None of the quantitative values of CT attenuation, ADC, and SUV showed significant differences between PPTs and germinomas (p > .05). However, there was a significant difference in age (p < .05) among the three groups of pineoblastoma (mean age ± standard deviation 7.0 ± 8.7 years), PPTID, and pineocytoma (53.7 ± 11.4 years) and germinoma (19.1 ± 8.1 years). Sex also showed significant differences between PPTs and germinomas (p = .039). Exploded pattern of calcification was found in 9 of 11 PPT patients and engulfed pattern in 7 of 9 patients with germinomas. No reverse pattern was observed, and the patterns of calcification were considered highly specific of tumor types. None of the quantitative imaging values could differentiate PPTs from germinomas. Age, sex, and calcification patterns were confirmed useful in differentiating these tumors to some degree.
    Neuroradiology 02/2014; · 2.37 Impact Factor
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    ABSTRACT: Background:Congenital porto-systemic shunt (CPSS) has the potential to cause hepatic encephalopathy thus needs long-term follow-up, but an effective follow-up method has not been established. We aimed to evaluate the importance of per-rectal portal scintigraphy (PRPS) for long-term follow-up of CPSS.Methods:We retrospectively examined shunt-severity time course in patients (median 9.6y, 5.2-16.6) with intrahepatic (n=3) or extrahepatic (n=3) CPSS by using blood tests, ultrasonography or computed tomography (CT), and PRPS. Per-rectal portal shunt index (SI, cut-off 10%) was calculated by PRPS.Results:PRPS demonstrated the initial SI reduced in all intrahepatic cases from 39.7±9.8% (mean±SD) to 14.6±4.7% and also reduced in all extrahepatic cases from 46.2±10.9% to 27.5±12.6% during follow-up period. However, ultrasonography and CT disclosed the different shunt diameter time course between intrahepatic and extrahepatic CPSS. Initial shunt diameter (5.8±3.5mm) reduced to 2.0±0.3mm in intrahepatic cases, but the initial diameter (6.3±0.7mm) increased to 10.6±1.0mm in extrahepatic cases. All patients had elevated serum total bile acid or ammonia levels at initial screening, but these blood parameters were insufficient to assess shunt severity because the values fluctuate.Conclusions:PRPS can track changes in the shunt-severity of CPSS and is more reliable than ultrasonography and CT in patients with extrahepatic CPSS.Pediatric Research (2014); doi:10.1038/pr.2014.11.
    Pediatric Research 01/2014; · 2.84 Impact Factor
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    ABSTRACT: Central neurocytoma was initially believed to be benign tumor type, although atypical cases with more aggressive behavior have been reported. Preoperative estimation for proliferating activity of central neurocytoma is one of the most important considerations for determining tumor management. To investigate predictive values of image characteristics and quantitative measurements of minimum apparent diffusion coefficient (ADCmin) and maximum standardized uptake value (SUVmax) for proliferative activity of central neurocytoma measured by MIB-1 labeling index (LI). Twelve cases of central neurocytoma including one recurrence from January 2001 to December 2011 were included. Preoperative scans were conducted in 11, nine, and five patients for computed tomography (CT), diffusion-weighted imaging (DWI), and fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET), respectively, and ADCmin and SUVmax of the tumors were measured. Image characteristics were investigated using CT, T2-weighted (T2W) imaging and contrast-enhanced T1-weighted (T1W) imaging, and their differences were examined using the Fisher's exact test between cases with MIB-1 LI below and above 2%, which is recognized as typical and atypical central neurocytoma, respectively. Correlational analysis was conducted for ADCmin and SUVmax with MIB-1 LI. A P value <0.05 was considered significant. Morphological appearances had large variety, and there was no significant correlation with MIB-1 LI except a tendency that strong enhancement was observed in central neurocytomas with higher MIB-1 LI (P = 0.061). High linearity with MIB-1 LI was observed in ADCmin and SUVmax (r = -0.91 and 0.74, respectively), but only ADCmin was statistically significant (P = 0.0006). Central neurocytoma had a wide variety of image appearance, and assessment of proliferative potential was considered difficult only by morphological aspects. ADCmin was recognized as a potential marker for differentiation of atypical central neurocytomas from the typical ones.
    Acta Radiologica 01/2014; · 1.35 Impact Factor
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    ABSTRACT: Balloon-occluded retrograde transvenous obliteration (B-RTO) has shown great potential in controlling acute gastric variceal hemorrhage, although rebleeding related to the procedure may occur in a small percentage of patients. The purpose of this study was to identify risk factors of perioperative rebleeding and prognostic factors of postoperative survival in B-RTO performed for acute episodes of gastric variceal hemorrhage. We retrospectively analyzed 39 consecutive patients who underwent B-RTO for gastric variceal rupture at our hospital between June 2003 and May 2011. Uni- and multi-variate analyses were performed to assess risk factors for perioperative rebleeding and prognostic factors for postoperative survival. Surgical success and complete eradication of varices were achieved in 36 cases (92.3 %) and 35 cases (89.7 %), respectively. Six patients experienced rebleeding either intraoperatively (n = 3) or within 1 h after B-RTO (n = 3). Child-Pugh class C was identified as a risk factor for rebleeding on univariate (P = 0.018) and multivariate analyses (odds ratio, 6.003; P = 0.014). With a median follow-up of 23 months (range 0-106.6 months), overall survival rates at 1, 3, and 5 years were 91.7, 74.7, and 67.2 %, respectively. Multivariate analyses revealed Child-Pugh class C as a prognostic factor for survival (relative risk, 4.014; P = 0.023). Although B-RTO is generally effective in the treatment of acute gastric variceal rupture, patients classified as Child-Pugh class C have a higher risk of perioperative rebleeding and shorter survival.
    CardioVascular and Interventional Radiology 01/2014; 37(5). · 2.09 Impact Factor
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    ABSTRACT: Abstract This report describes the successful use of portal venous stent placement for a patient with recurrent melena secondary to jejunal varices that developed after subtotal stomach preserved pancreatoduodenectomy (SSPPD). A 67-year-old man was admitted to our hospital with tarry stool and severe anemia at 2 years after SSPPD for carcinoma of the head of the pancreas. Abdominal computed tomography examination showed severe stenosis of the extrahepatic portal vein caused by local recurrence and showed an intensely enhanced jejunal wall at the choledochojejunostomy. Gastrointestinal bleeding scintigraphy also revealed active bleeding near the choledochojejunostomy. Based on these findings, jejunal varices resulting from portal vein stenosis were suspected as the cause of the melena. Portal vein stenting and balloon dilation was performed via the ileocecal vein after laparotomy. Coiling of the jejunal varices and sclerotherapy of the dilate postgastric vein with 5% ethanolamine oleate with iopamidol was performed. After portal stent placement, the patient was able to lead a normal life without gastrointestinal hemorrhage. However, he died 7 months later due to liver metastasis.
    International surgery 01/2014; 99(1):91-95. · 0.25 Impact Factor
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    ABSTRACT: To retrospectively evaluate risk factors for aggravation of esophageal varices (EV) within 1 year after balloon-occluded retrograde transvenous obliteration (B-RTO) of gastric varices (GV) and to clarify suitable timing for upper endoscopy to detect EV aggravation after B-RTO. Participants included 67 patients who underwent B-RTO for GV between January 2006 and December 2010. Whether EV aggravation occurred within 1 year was evaluated, and the time interval from B-RTO to aggravation was calculated. Factors potentially associated with EV aggravation were analyzed. B-RTO was successfully performed in all patients. EV aggravation at 1 year after B-RTO was found in 38 patients (56.7 %). Multivariate logistic regression analysis showed that total bilirubin (T-bil) (P = 0.032) and hepatic venous pressure gradient (HVPG) (P = 0.011) were significant independent risk factors for EV aggravation after B-RTO. Cutoff values of T-bil and HVPG yielding maximal combined sensitivity and specificity for EV aggravation were 1.6 mg/dL and 13 mmHg, respectively. The patients with T-bil ≥ 1.6 mg/dL or HVPG ≥ 13 mmHg had a median aggravation time of 5.1 months. All five patients with ruptured EV belonged to this group. In contrast, patients with T-bil < 1.6 mg/dL and HVPG < 13 mmHg had a median aggravation time of 21 months. T-bil and HVPG were significant independent risk factors for EV aggravation after B-RTO. The patients with T-bil ≥ 1.6 mg/dL or HVPG ≥ 13 mmHg require careful follow-up evaluation, including endoscopy.
    CardioVascular and Interventional Radiology 12/2013; 37(5). · 2.09 Impact Factor
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Publication Stats

673 Citations
181.35 Total Impact Points


  • 2005–2014
    • Osaka City University
      • • Department of Radiology
      • • Graduate School of Medicine
      Ōsaka, Ōsaka, Japan
    • Kinki University
      • Department of Radiology
      Ōsaka-shi, Osaka-fu, Japan
  • 2004–2014
    • Kyoto University
      • • Department of Diagnostic Imaging and Nuclear Medicine
      • • Graduate School of Medicine / Faculty of Medicine
      Kioto, Kyōto, Japan
  • 2011
    • Johns Hopkins University
      • Department of Radiology
      Baltimore, Maryland, United States
  • 2010
    • Otsu Red Cross Hospital
      Ōtu, Shiga Prefecture, Japan
  • 2009
    • Kyoto City Hospital
      Kioto, Kyōto, Japan