Tomoko Hyodo

Kinki University, Ōsaka, Ōsaka, Japan

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Publications (45)65.89 Total impact

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    ABSTRACT: Background: It remains unknown whether Kupffer-phase images in Sonazoid-enhanced ultrasonography (US) can be used to predict hypervascularization of borderline lesions. Therefore, we aimed to clarify whether Kupffer-phase images in Sonazoid-enhanced ultrasonography can predict subsequent hypervascularization in hypovascular borderline lesions detected on hepatobiliary-phase gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging. Methods: From January 2008 to March 2012, 616 low-intensity hypovascular nodules were detected in hepatobiliary-phase images of Gd-EOB-DTPA-enhanced MRI at nine institutions. Among these, 167 nodules, which were confirmed as hypovascular by Gd-EOB-DTPA-enhanced MRI and Sonazoid-enhanced US, were evaluated in this study. Potential hypervascularization factors were selected based on their clinical significance and the results of previous reports. The Kaplan-Meier model and log-rank test were used for univariate analysis and the Cox regression model was used for multivariate analysis. Results: The cumulative incidence of hypervascularization of borderline lesions was 18, 37, and 43 % at 1, 2, and 3 years, respectively. Univariate analyses showed that tumor size (p = 0.0012) and hypoperfusion on Kupffer-phase images in Sonazoid-enhanced US (p = 0.004) were associated with hypervascularization of the tumor. Multivariate analysis showed that tumor size [HR: 1.086, 95 % confidence interval = 1.027-1.148, p = 0.004] and hypo perfusion on Kupffer-phase images [HR: 3.684, 95 % confidence interval = 1.798-7.546, p = 0.0004] were significantly different. Conclusions: Kupffer-phase images in Sonazoid-enhanced US and tumor diameter can predict hypervascularization of hypointense borderline lesions detected on hepatobiliary-phase Gd-EOB-DTPA-enhanced MRI.
    No preview · Article · Sep 2015 · Journal of Gastroenterology
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    ABSTRACT: Methods: Static and BP images were constructed for 85 consecutive patients with cognitive impairment after (11)C-PiB dynamic PET. Cortical uptakes were visually assessed as positive, negative, or equivocal for both types of images. Quantitatively, the standardized uptake value ratio (SUVR) from the static image, the BPNONDISPLACEABLE (BPND) from the dynamic image for mean gray matter uptake, and the ratio of gray matter uptake to white matter retention were compared between PiB-positive, PiB-equivocal, and PiB-negative groups. Results: Forty-three scans were visually assessed as PiB-positive in both the static and BP images. Ten scans were PiB-equivocal in the static images. In eight of them, the BP images were PiB-positive, while the other two were PiB-equivocal. Thirty-two scans were assessed as PiB-negative in the static images. In the BP images, four were PiB-positive and 2 were PiB-equivocal. The mean gray matter uptake of (11)C-PiB in SUVR and BPND, respectively, showed statistically significant differences between the PiB-positive, -equivocal, and -negative groups. The ratio of gray matter uptake to white matter retention was lower in the BP images compared with static images from the PiB-negative and PiB-equivocal groups, whereas it was higher in the PiB-positive group. Conclusion: (11)C-PiB PET binding of potential images can clarify visual interpretation of clinical static PiB-equivocal images by reducing the interference of non-specific white matter retention. We conclude that PiB-equivocal PET findings on static images reflect cortical amyloid deposits, which can be verified using BP images. Furthermore, quantitative assessments, such as SUVR and BPnd, are of no use for correctly rating equivocal visual findings.
    No preview · Article · Sep 2015 · Journal of Nuclear Medicine
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    ABSTRACT: The purpose of this study was to investigate the usefulness of T1W black-blood Cube (BB Cube) and T1W BB Cube fluid-attenuated inversion recovery (BB Cube-FLAIR) sequences for contrast-enhanced brain imaging, by evaluating flow-related artefacts, detectability, and contrast ratio (CR) of intracranial lesions among these sequences and T1W-SE. Phantom studies were performed to determine the optimal parameters of BB Cube and BB Cube-FLAIR. A clinical study in 23 patients with intracranial lesions was performed to evaluate the usefulness of these two sequences for the diagnosis of intracranial lesions compared with the conventional 2D T1W-SE sequence. The phantom study revealed that the optimal parameters for contrast-enhanced T1W imaging were TR/TE = 500 ms/minimum in BB Cube and TR/TE/TI = 600 ms/minimum/300 ms in BB Cube-FLAIR imaging. In the clinical study, the degree of flow-related artefacts was significantly lower in BB Cube and BB Cube-FLAIR than in T1W-SE. Regarding tumour detection, BB Cube showed the best detectability; however, there were no significant differences in CR among the sequences. At 1.5 T, contrast-enhanced BB Cube was a better imaging sequence for detecting brain lesions than T1W-SE or BB Cube-FLAIR. • Cube is a single-slab 3D FSE imaging sequence. • We applied a black-blood (BB) imaging technique to T1W Cube. • At 1.5 T, contrast-enhanced T1W BB Cube was valuable for detecting brain lesions.
    No preview · Article · May 2015 · European Radiology
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    ABSTRACT: The purpose of this study was to characterize hepatic parenchymal enhancement for normal and diseased liver in dynamic computed tomography (CT) with the dose of contrast medium calculated on the basis of body surface area (BSA). The records of 328 consecutive patients who underwent triple-phase contrast-enhanced CT were retrospectively reviewed. The patients were divided into four groups: normal liver (n = 125), chronic hepatitis (CH) (n = 92), Child-Pugh grade A liver cirrhosis (LC-A) (n = 78), and Child-Pugh grade B liver cirrhosis (LC-B) (n = 33). All patients received 22 g I m(-2) as contrast material, calculated on the basis of BSA. CT values were measured in the region of interest during the pre-contrast, arterial, and portal phases, and the change in the CT value (ΔHU, where HU is Hounsfield units) compared with pre-contrast images was calculated. Mean ΔHU for the hepatic parenchyma for the normal liver, CH, LC-A, and LC-B groups during the portal phase was 55.5 ± 11.8 HU, 55.2 ± 12.5 HU, 50.0 ± 13.0 HU, and 43.0 ± 12.7 HU, respectively; generalized estimating equation analysis showed the differences were significant (p < 0.01). Hepatic parenchymal enhancement during the portal phase decreased as the severity of chronic liver damage increased.
    No preview · Article · Feb 2015 · Japanese journal of radiology
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    ABSTRACT: To compare four imaging approaches in cirrhotic estimation; pre-enhancement T1 relaxation time (T1RT), reduction rate (RR) of T1RT, signal-based liver-to-muscle ratio (L/M ratio) on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI), and liver stiffness measurement (LSM) of US elastography. Consecutive 58 patients with chronic liver diseases who underwent both Gd-EOB-DTPA-enhanced MRI and FibroScan were analyzed. Four imaging approaches were evaluated by fibrosis score from liver biopsy and receiver operating characteristic (ROC) analysis. RR was found to be inversely correlated with LSM (r = -0.65). RR decreased with degree of fibrosis (F0-F1, 58.5 ± 6.2%, versus F2-F3-F4, 48.8 ± 11.7%, P = 0.010, F0-F1-F2, 58.2 ± 6.2% versus F3-F4, 45.5 ± 12.3%, P = 0.010 and F0-F1, 58.5 ± 6.2%, versus F2-F3, 52.1 ± 12.0%, P = 0.0038). LSM increased with degree of fibrosis (F0-F1, 5.4 ± 2.2 kPa versus F2-F3-F3, 19.3 ± 15.5 kPa, P = 0.0011 and F0-F1-F2, 6.8 ± 3.6 kPa versus F3-F4, 23.8 ± 17.1 kPa, P = 0.0029 and F0-F1, 5.4 ± 2.2 kPa, versus F2-F3, 11.4 ± 7.2 kPa, P = 0.0098). Area under ROC curves were 0.83 (F3-F4), 0.72 (F2-F3-F4), 0.68 (F2-F3) for RR and 0.83 (F3-F4), 0.88 (F2-F3-F4), 0.81 (F2-F3) for LSM in discriminating between patients with fibrosis. The capability by LSM was better than those by RR of T1RT, pre-enhancement T1RT, and L/M ratio to differentiate F ≥ 2, but LSM and RR of T1RT showed the same value to differentiate F ≥ 3.J. Magn. Reson. Imaging 2013. © 2013 Wiley Periodicals, Inc.
    No preview · Article · Feb 2015 · Journal of Magnetic Resonance Imaging
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    ABSTRACT: To compare signal intensity (SI) correction using scale and rescale slopes with SI correction using SIs of spleen and muscle for quantifying multiphase hepatic contrast enhancement with Gd-EOB-DTPA by assessing their correlation with T1 values generated from Look-Locker turbo-field-echo (LL-TFE) sequence data (ER-T1). Thirty patients underwent Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in this prospective clinical study. For each patient, breath-hold T1-weighted fat-suppressed three-dimensional (3D) gradient echo sequences (e-THRIVE) were acquired before and 2 (first phase), 10 (second phase), and 20min (third phase) after intravenous Gd-EOB-DTPA. Look-Locker turbo-field-echo (LL-TFE) sequences were acquired before and 1.5 (first phase), 8 (second phase), and 18min (third phase) postcontrast. The liver parenchyma enhancement ratios (ER) of each phase were calculated using the SI from e-THRIVE sequences (ER-SI) and the T1 values generated from LL-TFE sequence data (ER-T1) respectively. ER-SIs were calculated in three ways: (1) comparing with splenic SI (ER-SI-s), (2) comparing with muscle SI (ER-SI-m), (3) using scale and rescale slopes obtained from DICOM headers (ER-SI-c), to eliminate the effects of receiver gain and scaling. For each of the first, second and third phases, correlation and agreement were assessed between each ER-SI and ER-T1. In the first phase, all ER-SIs correlated weakly with ER-T1. In the second and third phases, ER-SI-c showed a stronger linear correlation with ER-T1 (r(2)=0.71-0.72, p<0.01) than did ER-SI-s (r(2)=0.37-0.39, p<0.01) or ER-SI-m (r(2)=0.30-0.41, p<0.01). SI correction using scale and rescale slopes from DICOM data is the most acceptable algorithm for evaluating delayed-phase Gd-EOB-DTPA hepatic enhancement. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    No preview · Article · Nov 2014 · European Journal of Radiology
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    ABSTRACT: Objective: We have encountered occasional equivocal findings when assessing cerebral cortical amyloid retention with (11)C-Pittsburgh compound B (PiB) PET. We investigated the diagnostic significance of equivocal PiB PET findings. Methods: This retrospective study included 101 consecutive patients complaining of cognitive disorders (30 Alzheimer's disease, 25 mild cognitive impairment, 8 Lewy body disease, 7 frontotemporal lobar degeneration, 31 others) who underwent both (11)C-PiB PET and (18)F-fluorodeoxy-D-glucose (FDG) PET. We visually classified PiB-positive, PiB-equivocal or PiB-negative ratings according to cortical uptake. For quantitative assessments of PiB PET, standard uptake values referred to cerebellar cortex (SUVR) were calculated in regional template volume of interests (frontal, temporoparietal, precuneus/posterior cingulate cortex, cerebral white matter and cerebellar cortex). The results of visual assessment were compared with the regional and mean cortical SUVRs and cortical-to-white matter ratio of PiB uptake, as well as clinical and FDG PET findings. Results: Among the 101 scans, 41 were PiB negative, 11 were PiB equivocal, and 49 were rated PiB positive in the visual assessments. The mean cortical SUVR and cortical-to-white matter ratio were 0.97 ± 0.07 and 0.57 ± 0.21 in PiB-negative, 1.51 ± 0.17 and 0.75 ± 0.06 in PiB equivocal and 2.10 ± 0.33 and 0.97 ± 0.11 in PiB-positive group, respectively. Nine of 11 subjects with PiB-equivocal findings had cognitive impairments and FDG distribution compatible with Alzheimer's disease or dementia with Lewy bodies. Conclusions: We considered equivocal visual findings on PiB PET equivalent to PiB-positive with slight cortical uptake. In addition, slight cortical amyloid deposits were considered to cause cerebral metabolic abnormality and cognitive impairment. Although mean cortical SUVR was more sensitive than visual assessment because of low cortical-to-white matter contrast due to non-specific accumulation in white matter, it is important not to overlook small amounts of cortical uptake of PiB in visual inspection for exact diagnosis.
    Full-text · Article · Nov 2014 · Annals of Nuclear Medicine
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    ABSTRACT: Purpose: There is evidence that some cases of patients with dementia with Lewy bodies (DLB) can demonstrate Alzheimer disease (AD) like reduced glucose metabolism without amyloid deposition. The aim of this study was to clarify whether regional hypometabolism is related to amyloid deposits in the DLB brain and measure the degree of regional hypometabolism. Methods: Ten consecutive subjects with DLB and 10 AD patients who underwent both Pittsburgh compound B (PiB)-PET and (18)F-fluoro-2-deoxyglucose (FDG)-PET were included in this study. Regional standardized uptake value ratio (SUVR)s normalised to cerebellar cortices were calculated in the FDG- and PiB-PET images. Results: All AD patients and five DLB patients showed amyloid deposits (PiB positive). In the DLB group the parietotemporal and occipital metabolism were significantly lower than those in the AD group but there was no difference between the posterior cingulate hypometabolism between DLB and AD groups. There were no differences in regional glucose metabolism between PiB positive and negative DLB patients. Conclusions: In the DLB brain, it is suggested that decreased regional glucose metabolism is unrelated to amyloid deposits, although the hypometabolic area overlaps with the AD hypometabolic area and the degree of parietotemporal and occipital hypometabolism in DLB brain is much larger than that in AD brain.
    No preview · Article · Oct 2014 · Annals of Nuclear Medicine
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    ABSTRACT: To investigate optimal flip angle (FA) of three-dimensional fat-suppressed T1-weighted image on Gd-EOB-DTPA-enhanced MRI. Forty-five patients with 35 hepatocellular carcinomas (HCCs) and 16 liver metastases (METs) were investigated. Signal-to-noise ratio (SNR), tumor-to-liver contrast (TLC) of HCC and MET, visual image quality (IQ) and lesion conspicuity (LeCo) were evaluated at hepatobiliary phase with different FAs (FA15°-30°-45°-60° in 13 patients, FA5°-10°-15°-20°-25° in 32 patients). TLC gradually showed better in range from FA15° to FA60° and FA5° to FA25°, but SNRs gradually decreased. SNR and TLC-MET at FA15° were significantly better than those at FA45° and FA60°. SNR at FA10° was significantly higher than at FA5°, FA20°, and FA25°. TLC-HCC and TLC-MET at FA5° were inferior to other FAs. IQs and LeCos at FA15° and FA30° were superior to those at FA45° and FA60°. IQs at FA5° and FA25° were significantly lower than those at FA10°-20°, although LeCos for HCC and MET at FA25° were superior to those at FA5°-20°. FA ranging from 10° to 20° is suitable for hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI, to image HCC and MET.
    No preview · Article · Feb 2014 · Abdominal Imaging

  • No preview · Article · Jan 2014
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    ABSTRACT: PURPOSE To examine the optimal monochromatic levels to acquire a highest metastasis-to-liver contrast-to-noise ratio (CNR) on virtual monochromatic spectral (VMS) imaging by dual-energy CT (DECT) and the associations of the optimal monochromatic levels to patient body size METHOD AND MATERIALS 46 hypovascular hepatic metastases of twenty five patients were scanned by DECT in the portal venous phase. The scan was performed with fast kilovoltage switching between 80 and 140 kVp, detector collimation, 0.625 × 64 mm and helical pitch, 1.375. The tube current and rotation speed were adjusted to the computed tomography dose index-volume in a single energy CT acquisition at 120 kVp and Z-axis automatic tube current modulation technique (Noise Index=11). The highest metastasis-to-liver CNRs and the optimal monochromatic levels to acquire the highest metastasis-to-liver CNR on VMS imaging were measured, and their associations to patient body weight and body mass index (BMI) were examined. RESULTS The highest metastasis-to-liver CNR were 6.83±1.6 (range, 3.18-10.83). The optimal monochromatic levels to acquire the highest metastasis-to-liver CNR were 67.91±2.9 (range, 65-74 keV). There was significant positive correlation of the highest metastasis-to-liver CNR to the body weight (r=0.320, p<0.05) and the body mass index (r=0.506, p<0.05). There was a significant positive correlation of the optimal monochromatic level to the body weight (r=0.740, p<0.05) and the body mass index (r=0.637, p<0.05). CONCLUSION A significant positive correlation was observed between the body size and the optimal monochromatic level with regard to the metastasis-to-liver CNR on VMS imaging. Therefore, we consider that it is necessary to adjust an optimal monochromatic level according to the patient size for the evaluation of hepatic metastases on VMS imaging. CLINICAL RELEVANCE/APPLICATION This is the first study demonstrating the associations of the optimal monochromatic level to acquire a highest metastasis-to-liver CNR on virtual monochromatic spectral imaging to patient body size.
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: PURPOSE We performed a prospective randomized study using 4 protocols for multiphasic hepatic CT applying a combination of fixed injection duration and patients’ body-weight-tailored dose of contrast material, and to compare the quantitative and qualitative analyses among 4 protocols. METHOD AND MATERIALS This study was approved by the institutional review board. One hundred twenty patients were randomized into 4 groups: Group A (contrast material concentration; 370mgl/mL, fractional dose; 19.2mgI/kg/sec, injection duration; 25sec,and scan timing of arterial, portal, equilibrium phase;35/55/140sec, respectively), Group B (300mgl/mL, 16mgI/kg/sec, 30sec, 40/60/140sec), Group C (300mgl/mL, 15.8mgI/kg/sec, 38sec, 48/70/140sec), and Group D (370mgl/mL, 19.7mgI/kg/sec, 30sec,40/60/140sec). After performing imaging studies for the aorta, hepatic parenchyma, and portal vein, we compared their contrast enhancement among these 4 groups. In addition, we qualitatively evaluated the visualization of the aorta and portal vein. RESULTS The contrast enhancements of the aorta during the arterial phase were Group A/B/C/D=228.8/189.9/236.5/244.4 (HU), and there was no significant difference among Groups A, C, and D; furthermore, there was no difference in visual evaluation. The contrast enhancements of hepatic parenchyma during the portal and equilibrium phase were A/B/C/D= 41.8/42.3/58.7/50.9 (HU) and A/B/C/D= 36.7/34.3/44.9/42.4 (HU), respectively. There were significant differences between Group A and B, as well between as Group C and D, and also there is significant difference of visual evaluation of portal vein and hepatic parenchyma between C and other protocols. CONCLUSION Contrast enhancement of the aorta was dependent on fractional dose, while that of hepatic parenchyma was dependent on iodine dose. Good contrast enhancement of both the aorta and hepatic parenchyma could be achieved by using Group C, which indicated the potential usefulness of this method. CLINICAL RELEVANCE/APPLICATION A new protocol using longer injection duration of 38sec and middle concentration of contrast material may yield satisfactory enhancement.
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: PURPOSE The purpose of this study was to investigate the correlation between liver fat volume percentage (LFV%), obtained using a method based on multi-material decomposition (MMD) and histopathologic biopsy score in patients with nonalcoholic fatty liver disease (NAFLD) and alcoholic steatohepatitis. METHOD AND MATERIALS This study included 31 patients who underwent non-contrast (NC) and contrast-enhanced (CE) CT of the upper abdomen with dual energy CT (DECT) within 4 weeks prior to liver biopsy. The scan parameters employed for this study were 80/140kVp, 630mA, 0.6 sec/rot, 5mmTH, and helical mode. For CE studies, a non-ionic contrast agent was used and imaging was performed at the arterial, portal venous, and equilibrium phases. LFV% maps were generated from DECT data using MMD. For NC and CE exams, the measured LFV% was the average of 3 regions-of-interest (ROIs) that were placed in the hepatic parenchyma of the LFV% maps corresponding to the planned biopsy site. LFV% measurements were correlated with histopathologic grade of steatosis by the NAFLD activity (NAS) score. Differences in the mean LFV% for NC and CE data were tested by two-factor analysis of variance (ANOVA) with post hoc Tukey-Kramer test. Spearman rank correlations were calculated between NC LFV% and NAS steatosis score. RESULTS NAS steatosis scores were 0 in 4 patients, 1 in 15 patients, 2 in 12 patients and 3 in 0 patients. The mean LFV% of each NAS steatosis score group was 1.2%, 6.0% and 15.2%, respectively. Two-factor ANOVA results showed a statistically significant difference in LFV% by NAS score (P <0.01), but not by study phases (NC phase and all CE phases). With the Spearman rank test, a significant direct correlation was detected between LFV% and NAS steatosis score (ρ = 0.88, P < 0.01). CONCLUSION MMD-based LFV%, from both NC-CT and CE-CT data, shows statistically significant correlation to histopathologic biopsy grade, implying MMD can be used to accurately LFV% in the liver. Due to the agreement between LFV% across all phases of imaging (NC and CE), MMD can potentially obviate the need for the NC acquisition in DECT imaging of patients with fatty liver disease, which can lead to a significant reduction of radiation dose to patients. CLINICAL RELEVANCE/APPLICATION MMD-based method of LFV using fast-kV switching DECT enables accurate, non-invasive, and rapid measurement of LFV%. MMD may reduce total radiation dose by obviating the need for a NC-CT acquisition.
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: PURPOSE The purpose of this study was to retrospectively evaluate diagnostic efficacy of gadoxetic acid-enhanced magnetic resonance (MR) imaging compared with contrast-enhanced CT in the detection of hepatic metastasis in patients with colorectal carcinoma. METHOD AND MATERIALS Consecutive 158 patients with histopathologically confirmed colorectal carcinoma underwent gadoxetic acid-enhanced MR imaging and contrast-enhanced CT. Sixty-eight with 105 histopathological confirmed hepatic metastases by surgery. All MR studies were performed at a 3 T scanner (Magnetom Trio, Siemens Medical Systems, Germany or Achieva 3.0T TX, Philips Medical Solutions, Netherlands ) and CT were performed at 64-detector rows helical CT scanner (Aquilion Multi, Toshiba Medical, Japan). MR examination consisted of T1-weighted 3D-GRE dynamic sequences after bolus-injection of 0.025 mmol gadoxetic acid (Primovist; Bayer Schering Pharma, Japan). Diagnostic analysis was performed by sensitivity and positive predictive value (PPV) for the detection of hepatic metastases in combined arterial- and hepatocyte- phase images compared with contrast-enhanced CT by 2 blinded readers. Sensitivity and PPV for the detection of hepatic metastases were compared using McNemar test. Diagnostic accuracy and sensitivity were evaluated using the alternative-free response receiver operator characteristic (AFROC) method. RESULTS The overall sensitivity of gadoxetic acid-enhanced MR imagings (91.1%) were significantly higher than that of contrast-enhanced CT (78.5%, p<0.001), especially in the sensitivity of gadoxetic acid- enhanced MR imagings was observed in higher sensitivity in smaller size of lesions (76.2% vs 59.3% in the lesions ≤1cm, 97.0% vs 83.5% in the lesions 1 cm< ≤2cm, 98.3% vs 93.5% in the lesions >2cm). The gadoxetic acid-MR imagings showed significantly higher increased area under the ROC curve (Az value = 0.970) compared with contrast-enhanced CT (Az value = 0.899, p<0.01). CONCLUSION The results of this study demonstrated gadoxetic acid-enhanced MR imagings provided higher detectability for hepatic metastases, especially in smaller size of lesion, compared with contrast-enhanced CT in patients with colorectal carcinoma. CLINICAL RELEVANCE/APPLICATION Gadoxetic acid-enhanced MR imaging can detect smaller size of hepatic metastases compared with CT and would provide more feasible therapeutic direction for patients with colorectal carcinoma.
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: Background and purpose: Alzheimer disease is the most common neurodegenerative disorder with dementia, and a practical and economic biomarker for diagnosis of Alzheimer disease is needed. Three-dimensional arterial spin-labeling, with its high signal-to-noise ratio, enables measurement of cerebral blood flow precisely without any extrinsic tracers. We evaluated the performance of 3D arterial spin-labeling compared with SPECT, and demonstrated the 3D arterial spin-labeled imaging characteristics in the diagnosis of Alzheimer disease. Materials and methods: This study included 68 patients with clinically suspected Alzheimer disease who underwent both 3D arterial spin-labeling and SPECT imaging. Two readers independently assessed both images. Kendall W coefficients of concordance (K) were computed, and receiver operating characteristic analyses were performed for each reader. The differences between the images in regional perfusion distribution were evaluated by means of statistical parametric mapping, and the incidence of hypoperfusion of the cerebral watershed area, referred to as "borderzone sign" in the 3D arterial spin-labeled images, was determined. Results: Readers showed K = 0.82/0.73 for SPECT/3D arterial spin-labeled imaging, and the respective areas under the receiver operating characteristic curve were 0.82/0.69 for reader 1 and 0.80/0.69 for reader 2. Statistical parametric mapping showed that the perisylvian and medial parieto-occipital perfusion in the arterial spin-labeled images was significantly higher than that in the SPECT images. Borderzone sign was observed on 3D arterial spin-labeling in 70% of patients misdiagnosed with Alzheimer disease. Conclusions: The diagnostic performance of 3D arterial spin-labeling and SPECT for Alzheimer disease was almost equivalent. Three-dimensional arterial spin-labeled imaging was more influenced by hemodynamic factors than was SPECT imaging.
    No preview · Article · Nov 2013 · American Journal of Neuroradiology
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    ABSTRACT: Background and study aims: Pancreatic ductal adenocarcinomas (PDAC) sometimes arise in patients with intraductal papillary mucinous neoplasms (IPMNs). This study examined the incidence of PDACs concomitant to or derived from branch duct IPMNs. The usefulness of endoscopic ultrasonography (EUS) relative to other imaging methods for detecting these tumors was also assessed. Patients and methods: This retrospective study used data from clinical records and imaging studies that were collected prospectively. During 2001-2009, 167 consecutive patients with IPMNs underwent EUS, ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). The 102 patients whose branch duct IPMNs lacked mural nodules/symptoms and thus did not qualify for resection were followed up by semiannual EUS and annual ultrasonography, CT, and MRI. The sensitivity and specificity with which the four modalities detected IPMN-derived and -concomitant PDACs at the first examination and throughout the study period were evaluated. The rate of PDAC development during follow-up was analyzed by the Kaplan-Meier method. Results: A total of 17 IPMN-derived and 11 IPMN-concomitant PDACs were diagnosed at the first examination. Lesions that did not qualify for resection or chemotherapy were followed up for a median of 42 months. Seven IPMN-concomitant PDACs and no IPMN-derived PDACs were detected during follow-up. The 3- and 5-year rates of IPMN-concomitant PDAC development were 4.0% and 8.8%, respectively. At the first examination, EUS was superior to other imaging modalities in terms of IPMN-derived and -concomitant PDAC detection. Throughout the study period, including follow-up, EUS was significantly better at detecting IPMN-concomitant PDACs than the other modalities. Conclusions: IPMN-concomitant PDACs are quite often found at diagnosis and during follow-up. EUS examination of the whole pancreas plays an important role in the management of IPMNs as it allows the early detection of these small invasive carcinomas.
    No preview · Article · Nov 2013 · Endoscopy
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    ABSTRACT: Objective: We aimed to investigate the natural outcome of nonhypervascular lesions detected in the hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI by performing a longitudinal study retrospectively enrolled in a nationwide manner. Methods: Between February 2008 and March 2011, 224 patients with 504 nodules that were diagnosed as nonhypervascular by imaging were recruited from institutions that participated in the present study. We examined the natural outcome of nonhypervascular lesions and evaluated the risk factors. Results: Of the 504 nodules, 173 (34.3%) showed hypervascular transformation. The overall cumulative incidence of hypervascular transformation was 14.9% at 12 months and 45.8% at 24 months. Multivariate analysis using the Cox regression model revealed previous treatment history for hepatocellular carcinoma (HCC; relative risk = 1.498; p = 0.036, 95% CI 1.03-2.19) and hyperintensity on T2-weighted images (relative risk = 1.724; p = 0.015, 95% CI 1.11-2.67) were identified as independent factors for hypervascular transformation. Conclusions: Patients who have a previous treatment history for HCC and with hypointense nodules showing hyperintensity on T2-weighted images need careful follow-up because of the high incidence of hypervascular transformation.
    No preview · Article · Nov 2013 · Digestive Diseases
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    ABSTRACT: The aim of this study was to investigate the prevalence of intravertebral pneumatocyst (IVP) of the cervical spine by age group, compared with that of intradiscal vacuum (IDV). We investigated 500 consecutive patients who underwent cervical computed tomography (CT) from May 2012 to May2013 for various indications. CT datasets were assessed for the presence of IVPs and IDVs with stratification by age. IVPs of the cervical spine were detected in 8 % (7 of 86 subjects) of patients in their forties or below, 30 % (23 of 75) in their fifties, 49 % (67 of 136) in their sixties, 55 % (76 of 137) in their seventies, and 60 % (40 of 66) in their eighties or over. IDVs of the cervical spine were detected in 6, 25, 48, 54, and 57 %, respectively. Coexistence of both phenomena was identified in 4, 17, 33, 40, and 43 %, respectively. IVPs of the cervical spine are a common incidental finding, increasing in prevalence with age and more common than IDV in all age groups.
    No preview · Article · Oct 2013 · Neuroradiology
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    ABSTRACT: Purpose: To identify patient characteristics and magnetic resonance (MR) imaging findings associated with subsequent hypervascularization in hypovascular nodules that show hypointensity on hepatobiliary phase gadoxetic acid-enhanced MR images in patients with chronic liver diseases. Materials and methods: Institutional review board approval was obtained, and informed consent was waived. At multiple follow-up gadoxetic acid-enhanced MR imaging examinations of 68 patients, 160 hypovascular nodules were retrospectively reviewed. A Cox regression model for hypervascularization was developed to explore the association of baseline characteristics, including patient factors (Child-Pugh classification, etiology of liver disease, history of local therapy for hepatocellular carcinoma [HCC], and coexistence of hypervascular HCC) and MR imaging findings (fat content, signal intensity on T2-weighted images, and nodule size). In addition, the growth rate was calculated as the reciprocal of tumor volume doubling time to investigate its relationship with subsequent hypervascularization by using receiver operating characteristic and Kaplan-Meier analyses. Results: The prevalence of subsequent hypervascularization was 31% (50 of 160 nodules). Independent Cox multivariable predictors of increased risk of hypervascularization were hyperintensity on T2-weighted images (hazard ratio [HR] = 8.7; 95% confidence interval [CI]: 3.6, 20.8), previous local therapy for hypervascular HCC (HR = 5.0; 95% CI: 1.8, 13.6), Child-Pugh B cirrhosis (HR = 3.6; 95% CI: 1.4, 9.5) and coexistence of hypervascular HCC (HR = 2.0; 95% CI: 1.0, 3.8). The mean growth rate was significantly higher in nodules that showed subsequent hypervascularization than in those without hypervascularization. Kaplan-Meier analysis based on the receiver operating characteristic cutoff level (1.8 × 10(-3)/day [tumor volume doubling time, 542 days]) showed that nodules with a higher growth rate had a significantly higher incidence of hypervascularization (P = 5.2 × 10(-8), log-rank test). Conclusion: Hyperintensity on T2-weighted images is an independent and strong risk factor at baseline for subsequent hypervascularization in hypovascular nodules in patients with chronic liver disease. Tumor volume doubling time of less than 542 days was associated with a high rate of subsequent hypervascularization.
    No preview · Article · Feb 2013 · Radiology
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    ABSTRACT: Purpose To investigate whether low-dose dynamic CT of the liver with iterative reconstruction can reduce both the radiation dose and the amount of contrast medium. Materials and methods This study was approved by our institutional review board. 113 patients were randomly assigned to one of two groups. Group A/group B (fifty-eight/fifty-five patients) underwent liver dynamic CT at 120/100 kV, with 0/40% adaptive statistical iterative reconstruction (ASIR), with a contrast dose of 600/480 mgI/kg, respectively. Radiation exposure was estimated based on the manufacturer's phantom data. The enhancement value of the hepatic parenchyma, vessels and the tumor-to-liver contrast of hepatocellular carcinomas (HCCs) were compared between two groups. Two readers independently assessed the CT images of the hepatic parenchyma and HCCs. Results The mean CT dose indices: 6.38/4.04 mGy, the dose–length products: 194.54/124.57, for group A/group B. The mean enhancement value of the hepatic parenchyma and the tumor-to-liver contrast of HCCs with diameters greater than 1 cm in the post-contrast all phases did not differ significantly between two groups (P>0.05). The enhancement values of vessels in group B were significantly higher than that in group A in the delayed phases (P<0.05). Two reader's confidence levels for the hepatic parenchyma in the delayed phases and HCCs did not differ significantly between the groups (P>0.05). Conclusions Low-dose dynamic CT with ASIR can reduce both the radiation dose and the amount of contrast medium without image quality degradation, compared to conventional dynamic CT without ASIR.
    No preview · Article · Jan 2013 · European journal of radiology

Publication Stats

206 Citations
65.89 Total Impact Points


  • 2011-2015
    • Kinki University
      • Department of Radiology
      Ōsaka, Ōsaka, Japan
  • 2009
    • Ehime University
      • Department of Urology
      Matuyama, Ehime, Japan