Akio Hiwatashi

Kyushu University, Hukuoka, Fukuoka, Japan

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Publications (102)194.95 Total impact

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    ABSTRACT: PurposeTo evaluate the reproducibility of amide proton transfer (APT) imaging of brain tumors using a parallel transmission-based technique.Materials and Methods Thirteen patients with brain tumors (four low-grade gliomas, three glioblastoma multiforme, five meningiomas, and one malignant lymphoma) were included in the study. APT imaging was conducted at 3T using a 2-channel parallel transmission scheme with a saturation time of 2 seconds and B1 amplitude of 2 μT. A 2D fast spin-echo sequence with driven-equilibrium refocusing was used for imaging. Z-spectra were obtained at 25 frequency offsets from −6 to +6 ppm (step 0.5 ppm). A point-by-point B0 correction was performed with a B0 map. A scan–rescan reproducibility test was performed in two sessions on separate days for each patient. The interval between the two sessions was 4.8 ± 3.5 days. Regions-of-interest (ROIs) were placed to include the whole tumor for each case. A mean and 90-percentile value of APT signal for the whole tumor histogram was calculated for each session. The between-session and within-session reproducibility was evaluated using linear regression analysis, intraclass correlation coefficient (ICC), and a Bland-Altman plot.ResultsThe mean and 90-percentile values of the APT signal for whole tumor ROI showed excellent agreements between the two sessions, with R2 of 0.91 and 0.96 in the linear regression analysis and ICC of 0.95 and 0.97, respectively.Conclusion Parallel transmission-based APT imaging of brain tumors showed good reproducibility. J. Magn. Reson. Imaging 2015.
    Journal of Magnetic Resonance Imaging 03/2015; DOI:10.1002/jmri.24895 · 2.79 Impact Factor
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    ABSTRACT: The recent development in magnetic resonance(MR)hardware and techniques allows the acquisition of functional information, such as perfusion or metabolism, in addition to conventional anatomical information in of cancers.In this review article, various molecular imaging methods based on MR are introduced and their application and usefulness for diagnosis of cancer are discussed.Diffusion weighted image(DWI)is believed to correlate cell density and reflect malignancy of tumor. DWI has been widely used for the diagnosis and evaluation of responses to cancer treatment.Arterial spin labeling(ASL) allows acquisition of perfusion data without the use of any contrast agent and is expected to be an alternative or complementary method to dynamic contrast enhanced MR imaging.Amide proton transfer(APT)imaging reflects the amount of mobile peptide and proteins in cancer tissue, and could be a useful tool for assessing tumor malignancy or evaluating treatment responses.More specific measurement of cancer metabolites is available at the cost of spatial resolution by MR spectroscopy (MRS).Finally, the positron emission tomography(PET)/MR hybrid system enables simultaneous acquisition of functional/ anatomical information from MR imaging and molecular/metabolic information from PET imaging.Combining various molecular MR imaging methods with PET tracers may have a huge potential for clinical diagnosis of cancer.
    Gan to kagaku ryoho. Cancer & chemotherapy 03/2015; 42(3):257-260.
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    ABSTRACT: Volume isotropic simultaneous interleaved bright- and black-blood examination (VISIBLE) is a recently developed 3D MR sequence that provides simultaneous acquisitions of images with blood vessel suppression (Black) and images without it (Bright). Our purpose was to evaluate the usefulness of VISIBLE in detecting brain metastases. This prospective study included patients with suspected brain metastasis imaged with both VISIBLE and MPRAGE. From a data set, we compared the number of visualized blood vessels and the lesion-to-normal contrast-to-noise ratio (CNR) in 60 patients. We also performed an observer test to compare their diagnostic performance with VISIBLE, MPRAGE and only Black in 34 patients. Diagnostic performance was evaluated using a figure of merit (FOM), sensitivity, false-positive results per case (FPs/case) and reading time. The number of vessels was significantly fewer in Black compared to MPRAGE and Bright (P < 0.0001). CNR was significantly higher with both Black and Bright than with MPRAGE (P < 0.005). In the observer test, significantly higher sensitivity (P < 0.0001) and FOM (P < 0.0001), significantly shorter reading time (P = 0.0001) and similar FPs/case were achieved with VISIBLE compared to MPRAGE. Compared to only Black, VISIBLE resulted in comparable sensitivity, but significantly fewer FPs/case (P = 0.0008). VISIBLE can improve radiologists' diagnostic performance for brain metastasis. • VISIBLE can achieve higher sensitivity and shorter reading time than MPRAGE. • VISIBLE can achieve lower false-positive rates than blood vessel suppressed images. • Compared to MPRAGE, VISIBLE can improve diagnostic performance for brain metastasis.
    European Radiology 11/2014; 25(4). DOI:10.1007/s00330-014-3496-z · 4.34 Impact Factor
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    ABSTRACT: Objective We report the clinical application of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging to diagnose a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) in the acute phase.ResultsOn IVIM MR Images of this patient, higher perfusion (f) and diffusion (D) values in the left occipital and temporal lobes were found compared to the contralateral areas.Conclusion These findings imply a breakdown of autoregulation with hyperperfusion and vasogenic edema during the acute phase of MELAS, as described in previous reports. IVIM imaging is a valuable, noninvasive tool that simultaneously quantifies perfusion and diffusion parameters.
    11/2014; 4(6). DOI:10.1002/brb3.282
  • 43rd Annual Meeting of the Child-Neurology-Society; 10/2014
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    ABSTRACT: To reveal angiographic findings to predict the result of balloon test occlusion (BTO).
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    ABSTRACT: To evaluate the diagnostic performance of a double-dose administration of gadolinium for brain metastases at 3 T in a systematic observer test. Postcontrast MR images of 39 patients (total 104 metastases) were obtained by 3D T1-weighted sequences with both standard and cumulative double dose contrast administration. An observer test involving 9 radiologists (5 board-certified radiologists and 4 residents) was performed, and their diagnostic performance with the two doses was compared by means of sensitivity, false-positives, reading time, and a figure-of-merit. Compared to the standard dose, the double dose showed higher sensitivity (P < 0.0001), higher false-positive/case (P < 0.05), longer reading time (P < 0.05), and higher figure-of-merit (P < 0.0001). Particularly in small lesions (< 5 mm), sensitivity with the double dose (61.5 %, P < 0.0001) was approximately twice as high as that with the standard dose (29.5 %). Artifacts and blood vessels were the most common imaging findings resulting in false-positives. The double dose improved detection for metastases smaller than 5 mm at 3 T and thus resulted in better diagnostic performance of radiologists. However, a higher dose might result in prolonged reading time and increased false-positives, presumably due to increased vessel signals and frequency of flow-related artifacts.
    Japanese journal of radiology 06/2014; 32(9). DOI:10.1007/s11604-014-0342-9 · 0.74 Impact Factor
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    ABSTRACT: Bone density measurements using high-resolution CT have been reported to be useful to diagnose fenestral otosclerosis. However, small region of interest (ROI) chosen by less-experienced radiologists may result in false-negative findings. Semi-automatic analysis such as CT histogram analysis may offer improved assessment. The aim of this study was to evaluate the utility of CT histogram analysis in diagnosing fenestral otosclerosis. Temporal bone CT of consecutive patients with otosclerosis and normal controls was retrospectively analyzed. The control group consisted of the normal-hearing contralateral ears of patients with otitis media, cholesteatoma, trauma, facial nerve palsy, or tinnitus. All CT images were obtained using a 64-detector-row CT scanner with 0.5-mm collimation. AROI encompassing 10 × 10 pixels was placed in the bony labyrinth located anterior to the oval window. The mean CT value, variance and entropy were compared between otosclerosis patients and normal controls using Student's t test. The number of pixels below mean minus SD in the control (%Lowcont) and total subjects (%Lowtotal) were also compared. In addition, the area under the receiver operating characteristic curves (AUC) value for the discrimination between otosclerosis patients and normal controls was calculated. 51 temporal bones of 38 patients with otosclerosis and 30 temporal bones of 30 control subjects were included. The mean CT value was significantly lower in otosclerosis cases than in normal controls (p < 0.01). In addition, variance, entropy, %Lowcont and %Lowtotal were significantly higher in otosclerosis cases than in normal controls (p < 0.01, respectively). The AUC values for the mean CT value, %Lowcont and %Lowtotal were 0.751, 0.760 and 0.765, respectively. In conclusion, our results demonstrated that histogram analysis of CT image may be of clinical value in diagnosing otosclerosis.
    Archives of Oto-Rhino-Laryngology 02/2014; 271(12). DOI:10.1007/s00405-014-2933-6 · 1.61 Impact Factor
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    ABSTRACT: PURPOSE To evaluate the utility of the histogram-based analysis of multidetector row CT images in diagnosing otosclerosis. METHOD AND MATERIALS Temporal bone CT of consecutive patients with otosclerosis and normal controls were retrospectively analyzed. The diagnosis of otosclerosis was confirmed during surgery in all cases. The control group consisted of the normal-hearing contralateral ears in patients with otitis media, cholesteatoma, trauma, facial nerve paralysis, or tinnitus. All CT images were obtained using a 64-detector-row CT scanner with 0.5-mm collimation, 80 mm FOV, and a 512 × 512 matrix. A region-of- interest (ROI) encompassing 10 × 10 pixels was placed in the bony labyrinth located anterior to oval window. For each ROI, histogram-based metrics including the mean CT value, variance, kurtosis, skewness were measured. In addition, the energy, contrast, and entropy were derived from the texture analysis. Each metric was compared between the otosclerosis and normal controls groups using Student’s t-test. In addition, the area under the ROC curves (AUC) value for the discrimination between otosclerosis and normal controls was calculated. RESULTS Fifty one temporal bones of 38 patients with otosclerosis (mean age: 49.0 ± 12.4 years old) and 30 control subjects (mean age: 44.6 ± 17.0 years old) were included. The mean CT value, contrast, and energy were significant lower in otosclerosis cases than normal controls (p<0.01, respectively). In addition, the variance and entropy were significant higher in otosclerosis cases than normal controls (p<0.01, respectively). The AUC values for the mean CT value, variance, energy, contrast, and entropy were 0.754, 0.688, 0.669, 0.745 and 0.664, respectively. CONCLUSION Our results demonstrated that the histogram-based analysis of CT images is useful to diagnose otosclerosis. In particular, the mean CT value and the contrast showed higher diagnostic values. CLINICAL RELEVANCE/APPLICATION The histogram-based analysis of multidetector row CT images can be an effective and operator independent tool for diagnosis of fenestral otosclerosis.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: PURPOSE To assess the feasibility of high–resolution three dimensional diffusion–weighted images (HR3D–DWI) / multi–detector row CT (MDCT) images data fusion for surgical planning for cholesteatoma. METHOD AND MATERIALS A total of 14 patients (M/F= 7/7, age 11 to 72 years, mean 42.5 years) with acquired cholesteatoma underwent preoperative MRI using a 3.0 T clinical unit and an 8-channel head coil. For each subject, HR3D–DWIs were obtained using a turbo field–echo with diffusion–sensitized driven-equilibrium preparation with following parameters: TR/TE = 6.2/3ms, FA = 10°, ETL = 75, b factor = 800s/mm2, voxel size = 1.5×1.5×1.5mm3, NEX = 2, SENSE factor = 2, and acquisition time = 5min19s. These patients also underwent MDCT with a slice thickness of 0.5mm. Fusion of the HR3D–DWIs and MDCT images was performed using a landmark rigid registration method by a board–certified neuroradiologist on a workstation. The location and extent of cholesteatomas on the fused images was compared with the intraoperative findings. RESULTS On the fused images, the extent of the cholesteatoma, which was depicted as a conspicuous high intensity lesion could be easily evaluated with background bony structures. In all patients, the location and extent of the cholesteatoma on the fused images corresponded well with the intraoperative findings. CONCLUSION Image fusion between HR3D–DWI and MDCT images is feasible, and provides valuable preoperative information for surgical planning to otorhinolaryngologists. CLINICAL RELEVANCE/APPLICATION Our HR 3D–DWI has isotropic voxel dimensions that enables reformation in any arbitrary plane. It makes easier anatomical registration with CT images and leads to advantages of preoperative planning.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: PURPOSE Amide proton transfer (APT) imaging is a specific type of endogenous chemical exchange saturation transfer (CEST) imaging for detection of the amide protons included in mobile proteins and peptides. The purpose of this study was to evaluate the usefulness of APT imaging in grading diffuse gliomas by comparisons with contrast-enhanced and diffusion-weighted imaging (DWI). METHOD AND MATERIALS Consecutive 35 patients with histopathologically proven diffuse glioma (47.7±16.3 year-old, 14 males and 21 females, 6 grade II, 11 grade III and 18 grade IV) were included in the prospective study. MR imaging was conducted on a 3T clinical scanner using an 8-ch head coil for signal reception and 2-channel parallel transmission via the body coil. Saturation pulse: Tsat=2.0s, B1,rms=2.0μT. 2D turbo spin-echo sequences with driven equilibrium refocusing were used for imaging. Other parameters were as follows: TR/TR=5s/6ms, FOV=2302mm2, resolution=1.8×1.8×5mm3, 25 saturation frequency offsets ω=-6..6ppm (step 0.5ppm) and ω = -160ppm, affording 2 minutes scanning time. δB0 maps were acquired separately for a δB0 correction. APT signal intensity (SI) was defined as: MTRasym = (S[-3.5ppm]-S[+3.5ppm])/S0. Regions-of-interest were carefully placed in solid components within brain tumors. In addition, contrast enhancements (CE) in the tumors were visually graded on a 5-point scale, and minimum apparent diffusion coefficients (ADCmin) within the tumors were determined on DWI. RESULTS High-grade gliomas (HGG, grade III or IV) showed significantly stronger contrast enhancement (P<.005), lower ADC (P<.05) and higher APT SI (P<.0001) compared with low-grade gliomas (LGG, grade II). ROC analyses showed that APT imaging provided the best AUC value among these three parameters (CE: 0.88, ADC: 0.81 APT: 0.99) in discriminating HGG from LGG. Excellent sensitivity (97%) and specificity (100%) were achieved by APT imaging, while those of CE were 79% and 83%, and those of ADCmin were 79% and 83%, respectively. CONCLUSION APT imaging can provide better diagnostic performance in differentiating HGG from LGG compared with contrast-enhanced MR imaging and DWI. CLINICAL RELEVANCE/APPLICATION APT imaging can provide better diagnostic performance in discriminating HGG from LGG compared with conventional MR imaging sequences.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: Background Amide proton transfer (APT) imaging is a novel molecular MRI technique to detect endogenous mobile proteins and peptides through chemical exchange saturation transfer. We prospectively assessed the usefulness of APT imaging in predicting the histological grade of adult diffuse gliomas.Methods Thirty-six consecutive patients with histopathologically proven diffuse glioma (48.1 ± 14.7 y old, 16 males and 20 females) were included in the study. APT MRI was conducted on a 3T clinical scanner and was obtained with 2 s saturation at 25 saturation frequency offsets ω = -6 to +6 ppm (step 0.5 ppm). δB0 maps were acquired separately for a point-by-point δB0 correction. APT signal intensity (SI) was defined as magnetization transfer asymmetry at 3.5 ppm: magnetization transfer ratio (MTR)asym = (S[-3.5 ppm] - S[+3.5 ppm])/S0. Regions of interest were carefully placed by 2 neuroradiologists in solid parts within brain tumors. The APT SI was compared with World Health Organization grade, Ki-67 labeling index (LI), and cell density.ResultsThe mean APT SI values were 2.1 ± 0.4% in grade II gliomas (n = 8), 3.2 ± 0.9% in grade III gliomas (n = 10), and 4.1 ± 1.0% in grade IV gliomas (n = 18). Significant differences in APT intensity were observed between grades II and III (P < .05) and grades III and IV (P < .05), as well as between grades II and IV (P < .001). There were positive correlations between APT SI and Ki-67 LI (P = .01, R = 0.43) and between APT SI and cell density (P < .05, R = 0.38). The gliomas with microscopic necrosis showed higher APT SI than those without necrosis (P < .001).ConclusionsAPT imaging can predict the histopathological grades of adult diffuse gliomas.
    Neuro-Oncology 12/2013; DOI:10.1093/neuonc/not158 · 5.29 Impact Factor
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    ABSTRACT: PURPOSE Post-contrast 3D gradient-echo is the standard for brain metastases, but enhancing blood vessel can be a disturbing factor. Recent studies have shown that blood vessel suppression techniques help detect metastases more efficiently. However, incompletely suppressed vessels may closely mimic metastases, hence can result in false positive results. To solve this issue, we developed a novel 3D sequence named volume isotropic simultaneous interleaved bright- and black-blood examination (VISIBLE), which allows for simultaneous acquisitions of images with blood vessel suppression (Black images) and those without (Bright images) in 5 minutes. Our purpose was to evaluate usefulness of VISIBE through an observer study. METHOD AND MATERIALS In VISIBLE, two sequential phases of TFE acquisition are implemented following a motion-sensitized driven-equilibrium preparation for black-blood imaging. Patients with suspected brain metastasis were prospectively imaged using both VISIBLE and conventional MPRAGE. 34 patients including consecutive 17 patients with 1 to 6 metastases and 17 with no metastasis were selected and used for the observer study. 3 radiologists read VISBLE and MPRAGE of the 34 patients in the first and second reading session. In reading VISIBLE, each observer was instructed to use Black images to pick up high signal intensity areas as candidates for metastases and Bright images as a second opinion to reject false positives such as incompletely suppressed enhancing vessels. The observers’ diagnostic performance was evaluated by means of the figure-of-merit (FOM) as an index of diagnostic performance derived from the JAFROC analysis, sensitivity, false-positive per case (FP/case), and reading time. RESULTS Compared to MPRAGE, VISIBLE was associated with significantly higher sensitivity (91.7±4.2% for VISBLE vs. 70.8±11.1% for MPRAGE, P<.05), significantly higher FOM (0.94±0.02 vs. 0.82±0.05, P<.05), and significantly shorter reading time (108.4±57.8 sec vs. 149.5±74.7 sec, P<.05). FP/case was fewer with VISIBLE (0.13±0.12 vs. 0.23±0.22), although it did not reach statistical significance. CONCLUSION VISIBLE can improve radiologists’ diagnostic performance in detecting brain metastases. CLINICAL RELEVANCE/APPLICATION VISIBLE is capable of simultaneous acquisitions with and without blood vessel suppression and can improve radiologists’ diagnostic performance in detecting brain metastases.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: 3D turbo field echo with diffusion-sensitised driven-equilibrium preparation (DSDE-TFE) is a novel non-echo planar technique for diffusion-weighted (DW) imaging. The purpose of this study was to differentiate intraorbital lymphoma from immunoglobulin G4-related disease (IgG4-RD) using the apparent diffusion coefficient (ADC) derived from DSDE-TFE. Fifteen patients with lymphomas and 8 with IgG4-RDs underwent imaging. ADC and signal intensities compared with normal grey matter on T1-weighted images, fat-suppressed T2-weighted images and fat-suppressed postcontrast T1-weighted images were measured. Statistical analyses were performed using the Mann-Whitney U test and receiver operating characteristic (ROC) analysis. Intraorbital lesions were clearly visualised on DSDE-TFE without obvious geometrical distortion. The ADC of lymphoma (1.25 ± 0.50 × 10(-3) mm(2)/s; mean ± standard deviation) was significantly lower than that of IgG4-RD (1.67 ± 0.84 × 10(-3) mm(2)/s; P < 0.05). Conventional sequences could not separate lymphoma from IgG4-RD (0.93 ± 0.18 vs. 0.94 ± 0.21 on T1-weighted images, 0.92 ± 0.17 vs. 0.95 ± 0.14 on T2-weighted images and 2.03 ± 0.35 vs. 2.30 ± 0.58 on postcontrast T1-weighted images, for lymphoma and IgG4-RD, respectively; P > 0.05). ROC analysis showed the best diagnostic performance with ADC. The apparent diffusion coefficient derived from diffusion-sensitised driven-equilibrium preparation techniques may help to differentiate lymphoma from immunoglobulin G4-related disease. • Distinguishing between orbital lymphoma and immunoglobulin G4-related disease can be difficult • Intraorbital lesions were clearly visualised on diffusion-sensitised driven-equilibrium preparation magnetic resonance techniques. • Variations in field homogeneity do not affect DSDE-TFE techniques all that much. • ADCs derived from DSDE-TFE may help differentiate lymphoma from IgG4-RD.
    European Radiology 11/2013; DOI:10.1007/s00330-013-3058-9 · 4.34 Impact Factor
  • 08/2013; 24(4). DOI:10.1007/s00062-013-0254-6
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    ABSTRACT: We are the first to report a case that showed spontaneous resolution of epidural hematoma which was related to a steroid-induced osteoporotic compression fracture. The patient had a painful fracture with an intravertebral cleft at L1 accompanying an epidural hematoma posteriorly. Immediate pain relief was achieved after percutaneous vertebroplasty. Complete resolution of hematoma was noted three months after procedure. We theorized that intravertebral stability after treatment might have played a role in this patient.
    08/2013; 5(8):325-7. DOI:10.4329/wjr.v5.i8.325
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    ABSTRACT: BACKGROUND AND PURPOSE:3D turbo field echo with diffusion-sensitized driven-equilibrium preparation is a non-echo-planar technique for DWI, which enables high-resolution DWI without field inhomogeneity-related image distortion. The purpose of this study was to evaluate the feasibility of diffusion-sensitized driven-equilibrium turbo field echo in evaluating diffusivity in the normal pituitary gland.MATERIALS AND METHODS:First, validation of diffusion-sensitized driven-equilibrium turbo field echo was attempted by comparing it with echo-planar DWI. Five healthy volunteers were imaged by using diffusion-sensitized driven-equilibrium turbo field echo and echo-planar DWI. The imaging voxel size was 1.5 × 1.5 × 1.5 mm(3) for diffusion-sensitized driven-equilibrium turbo field echo and 1.5 × 1.9 × 3.0 mm(3) for echo-planar DWI. ADCs measured by the 2 methods in 15 regions of interests (6 in gray matter and 9 in white matter) were compared by using the Pearson correlation coefficient. The ADC in the pituitary anterior lobe was then measured in 10 volunteers by using diffusion-sensitized driven-equilibrium turbo field echo, and the results were compared with those in the pons and vermis by using a paired t test.RESULTS:The ADCs from the 2 methods showed a strong correlation (r = 0.79; P < .0001), confirming the accuracy of the ADC measurement with the diffusion-sensitized driven-equilibrium sequence. The ADCs in the normal pituitary gland were 1.37 ± 0.13 ×10(-3) mm(2)/s, which were significantly higher than those in the pons (1.01 ± 0.24 ×10(-3) mm(2)/s) and the vermis (0.89 ± 0.25 ×10(-3) mm(2)/s, P < .01).CONCLUSIONS:We demonstrated that diffusion-sensitized driven-equilibrium turbo field echo is feasible in assessing ADC in the pituitary gland.
    American Journal of Neuroradiology 07/2013; 35(1). DOI:10.3174/ajnr.A3620 · 3.68 Impact Factor
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    ABSTRACT: OBJECTIVE: To prospectively evaluate the usefulness of a newly developed high-resolution three-dimensional diffusion-weighted imaging method, turbo field-echo with diffusion-sensitized driven-equilibrium (TFE-DSDE) in diagnosing middle-ear cholesteatoma by comparing it to conventional single-shot echo-planar diffusion-weighted imaging (SS-EP DWI). MATERIALS AND METHODS: Institutional review board approval and informed consent from all participants were obtained. We studied 30 patients with preoperatively suspected acquired cholesteatoma. Each patient underwent an MR examination including both SS-EP DWI and DSDE-TFE using a 3.0T MR scanner. Images of the 30 patients (60 temporal bones including 30 with and 30 without cholesteatoma) were reviewed by two independent neuroradiologists. The confidence level for the presence of cholesteatoma was graded on a scale of 0-2 (0=definite absence, 1=equivocal, 2=definite presence). Interobserver agreement as well as sensitivity, specificity, and accuracy for detection were assessed for the two reviewers. RESULTS: Excellent interobserver agreement was shown for TFE-DSDE (κ=0.821) whereas fair agreement was obtained for SS-EP DWI (κ=0.416). TFE-DSDE was associated with significantly higher sensitivity (83.3%) and accuracy (90.0%) compared to SS-EP DWI (sensitivity=35.0%, accuracy=66.7%; p<0.05). No significant difference was found in specificity (96.7% for TFE-DSDE, 98.3% for SS-EP DWI) CONCLUSION: With increased spatial resolution and reduced susceptibility artifacts, TFE-DSDE improves the accuracy in diagnosing acquired middle ear cholesteatomas compared to SS-EP DWI.
    European journal of radiology 05/2013; 82(9). DOI:10.1016/j.ejrad.2013.04.018 · 2.16 Impact Factor
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    ABSTRACT: PURPOSE: The aim of this study was to evaluate the usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo (3D T1-GRE) images for the preoperative anatomical evaluation of lumbosacral lipoma, thick filum terminale, and myelomeningocele as a means of compensating for the drawbacks of 3D heavily T2-weighted (3D hT2-W) images. METHODS: Nine patients with lumbosacral lipomas, one patient with tight filum terminale, and five patients with myelomeningoceles were included in this study. 3D T1-GRE images were compared with 3D hT2-W images or conventional magnetic resonance images in terms of delineation of lipomas and other structures in the patients with lipomas and tight filum terminale. For patients with myelomeningoceles, 3D T1-GRE images were compared with 3D hT2-W images in terms of artifacts in the cerebrospinal fluid (CSF) space. RESULTS: The 3D T1-GRE images demonstrated lipomas with good contrast to the spinal cord and CSF space and more clearly delineated the anatomical relationship between lipomas and these structures than did the 3D hT2-W images. The 3D T1-GRE images delineated dural defects through which extradural lipomas penetrated into the intradural space. The 3D T1-GRE images also demonstrated the presence or absence of lipomas in the filum terminale and the absence of artifact in the myelomeningoceles. Furthermore, they were useful for differentiating artifacts observed on the 3D hT2-W images from nerve elements. CONCLUSIONS: The complementary use of 3D T1-GRE and 3D hT2-W images may compensate for the drawbacks of 3D hT2-W images and may eventually improve lesion visualization and surgical decision making.
    Child s Nervous System 05/2013; DOI:10.1007/s00381-013-2140-6 · 1.16 Impact Factor
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    ABSTRACT: BACKGROUND: Cognitive impairment is a frequent complication of moyamoya disease (MMD) in adults. Chronic hypoperfusion in frontal lobes can lead to subtle brain injury, resulting in cognitive dysfunctions. Apparent diffusion coefficient (ADC) in normal-appearing white matter on conventional magnetic resonance imaging correlates with cerebral hemodynamics in the frontal lobe. OBJECTIVE: The purpose of this study was to examine the relationship of ADC with executive function in patients with MMD. METHODS: Thirty-one patients (25 women and 6 men; mean age, 32.6 ± 10.4 years) were included in this study. Executive function was evaluated by the Frontal Assessment Battery (FAB) at 21.5 ± 7.5 years after disease onset. ADC was measured in the normal-appearing frontal white matter. RESULTS: ADC was statistically related to the occurrence of executive dysfunction in multivariate analysis (P = .0179). Total FAB score and ADC were negatively correlated (r(2) = .22; P = .0072; Spearman correlation coefficient, -.41; P = .024). Elevated ADC predicted executive dysfunction (area under the receiver operating characteristic curve, .73; 95% confidence interval, .55-.91; P = .029). CONCLUSIONS: The association of ADC with executive function might suggest that ADC is useful in screening for executive dysfunction during follow-up in the outpatient setting.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 04/2013; 23(3). DOI:10.1016/j.jstrokecerebrovasdis.2013.03.022 · 1.99 Impact Factor

Publication Stats

1k Citations
194.95 Total Impact Points

Institutions

  • 2007–2015
    • Kyushu University
      • • Graduate School of Medical Sciences
      • • Department of Clinical Radiology
      Hukuoka, Fukuoka, Japan
  • 2013
    • University of Texas Southwestern Medical Center
      Dallas, Texas, United States
  • 2004–2009
    • University of Rochester
      • Department of Imaging Sciences
      Rochester, New York, United States
  • 2002–2007
    • University Center Rochester
      • • Department of Imaging Sciences
      • • Department of Radiology
      • • Department of Diagnostic Radiology
      Rochester, Minnesota, United States