Akio Hiwatashi

Kyushu University, Hukuoka, Fukuoka, Japan

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Publications (110)207.24 Total impact

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    ABSTRACT: Background Pure dysarthria (PD) and dysarthria-facial paresis syndrome (DFP) mainly result from lenticulostriate artery territory infarction. PD and DFP are rare clinical entities, often grouped without distinction. The purpose of this study was to examine clinical and radiographic differences between PD and DFP due to unilateral internal capsule and/or corona radiata infarction. Methods Using a database that included consecutive patients with ischemic stroke admitted to the neurological stroke units of three hospitals within 7 days from onset between September 2011 and April 2014, we retrospectively extracted first-ever stroke patient data, who presented with PD or DFP with a single ischemic lesion localized in the internal capsule and/or corona radiata. Patients with weakness, ataxia, sensory deficit, or cortical symptoms were excluded. Ischemic lesion volume was calculated by the ABC/2 method on diffusion-weighted imaging (DWI). DWI images were normalized and superimposed to the template for PD and DFP. We compared patients' characteristics between PD and DFP. Results A total of 2126 patients, including 65 patients (3.1 %) with PD or DFP, were registered. Of these, 13 PD patients and 18 patients with DFP due to unilateral internal capsule and/or corona radiata infarction were included for analysis. Compared with DFP patients, PD patients had longer onset-to-door time (median 37.5 vs. 10.8 h, p = 0.031), shorter vertical length (C component) of ischemic lesions (median 12.0 vs. 18.8 mm, p = 0.007), and smaller ischemic lesion volume (median 285 vs. 828 mm3, p = 0.023). Ischemic lesions causing PD were located more frequently in the left hemisphere than DFP (92 % vs. 56 %, p = 0.045). The superimposed lesion pattern indicated that DFP had lesions more medial and involving posterior portions of the putamen and the caudate body, as well as more of the genu and posterior limb of the internal capsule, than PD. Ninety days after onset, symptoms disappeared in 21 (72 %) out of 29 patients. Conclusions In cerebral infarction limited to the internal capsule and/or corona radiata, PD is derived from smaller and left-sided lesions with delay in diagnosis compared with DFP. The clinical course of those with PD and DFP might be benign.
    Preview · Article · Dec 2015 · BMC Neurology
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    ABSTRACT: Purpose: To compare the utility and limitations of prenatal magnetic resonance (MR) imaging using half-Fourier acquisition single-shot turbo spin-echo (HASTE) with postnatal heavily T2-weighted imaging (hT2WI) for the evaluation of central nervous system abnormalities associated with myelomeningocele (MMC). Methods: Sixteen patients with MMC who had undergone pre- and postnatal MR imaging were included in this study. MR imaging, including HASTE, was undertaken in the 3rd trimester, and hT2WI was performed immediately after delivery. The precision with which each could distinguish MMC, hindbrain herniation and ventriculomegaly was compared retrospectively. Results: The skin defects and MMC sacs were clearly visible on prenatal HASTE images, although it was difficult to identify precisely the level of MMC compared with postnatal hT2WI, in which the detailed anatomical relationships of the spinal cord, neural placode and ventral nerve roots were evident in every case. Hindbrain herniation could be visualized on prenatal HASTE images, although its severity was difficult to evaluate because of the small size of the structures and neck flexion; again, the resolution was superior on postnatal hT2WI. For hydrocephalus, there were no significant differences in the diagnostic precision and ability to grade the severity between pre- and postnatal imaging. Conclusion: Prenatal HASTE imaging permits the diagnosis and understanding of the gross anatomy of MMC and associated hindbrain herniation and ventriculomegaly, but postnatal hT2WI is superior for evaluating detailed anatomy.
    Full-text · Article · Sep 2015 · Pediatric Neurosurgery
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    ABSTRACT: BACKGROUND AND PURPOSE: Glioblastoma multiforme is highly aggressive and the most common type of primary malignant brain tumor in adults. Imaging biomarkers may provide prognostic information for patients with this condition. Patients with glioma with isocitrate dehydrogenase 1 (IDH1) mutations have a better clinical outcome than those without such mutations. Our purpose was to investigate whether the IDH1 mutation status in glioblastoma multiforme can be predicted by using MR imaging. MATERIALS AND METHODS: We retrospectively studied 55 patients with glioblastoma multiforme with wild type IDH1 and 11 patients with mutant IDH1. Absolute tumor blood flow and relative tumor blood flow within the enhancing portion of each tumor were measured by using arterial spin-labeling data. In addition, the maximum necrosis area, the percentage of cross-sectional necrosis area inside the enhancing lesions, and the minimum and mean apparent diffusion coefficients were obtained from contrast-enhanced T1-weighted images and diffusion-weighted imaging data. Each of the 6 parameters was compared between patients with wild type IDH1 and mutant IDH1 by using the Mann-Whitney U test. The performance in discriminating between the 2 entities was evaluated by using receiver operating characteristic analysis. RESULTS: Absolute tumor blood flow, relative tumor blood flow, necrosis area, and percentage of cross-sectional necrosis area inside the enhancing lesion were significantly higher in patients with wild type IDH1 than in those with mutant IDH1 (P < .05 each). In contrast, no significant difference was found in the ADC(minimum) and ADC(mean). The area under the curve for absolute tumor blood flow, relative tumor blood flow, percentage of cross-sectional necrosis area inside the enhancing lesion, and necrosis area were 0.850, 0.873, 0.739, and 0.772, respectively. CONCLUSIONS: Tumor blood flow and necrosis area calculated from MR imaging are useful for predicting the IDH1 mutation status.
    Preview · Article · Sep 2015 · American Journal of Neuroradiology
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    ABSTRACT: Objective To investigate anti-neurofascin 155 (NF155) antibody-positive chronic inflammatory demyelinating polyneuropathy (CIDP).Methods Sera from 50 consecutive CIDP patients diagnosed in our clinic, 32 patients with multiple sclerosis, 40 patients with other neuropathies including 26 with Guillain–Barré syndrome (GBS)/Fisher syndrome, and 30 healthy controls were measured for anti-NF antibodies by flow cytometry using HEK293 cell lines stably expressing human NF155 or NF186. Four additional CIDP patients with anti-NF155 antibodies referred from other clinics were enrolled for clinical characterization.ResultsThe positivity rate for anti-NF155 antibodies in CIDP patients was 18% (9/50), who all showed a predominance of IgG4 subclass. No other subjects were positive, except one GBS patient harboring IgG1 anti-NF155 antibodies. No anti-NF155 antibody carriers had anti-NF186 antibodies. Anti-NF155 antibody-positive CIDP patients had a significantly younger onset age, higher frequency of drop foot, gait disturbance, tremor and distal acquired demyelinating symmetric phenotype, greater cervical root diameter on magnetic resonance imaging neurography, higher cerebrospinal fluid protein levels, and longer distal and F-wave latencies than anti-NF155 antibody-negative patients. Marked symmetric hypertrophy of cervical and lumbosacral roots/plexuses was present in all anti-NF155 antibody-positive CIDP patients examined by neurography. Biopsied sural nerves from two patients with anti-NF155 antibodies demonstrated subperineurial edema and occasional paranodal demyelination, but no vasculitis, inflammatory cell infiltrates, or onion bulbs. Among anti-NF155 antibody-positive patients, treatment responders more frequently had daily oral corticosteroids and/or immunosuppressants in addition to intravenous immunoglobulins than nonresponders did.InterpretationAnti-NF155 antibodies occur in a subset of CIDP patients with distal-dominant involvement and symmetric nerve hypertrophy.
    Full-text · Article · Sep 2015
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    ABSTRACT: Our aim was to assess the diagnostic performance of intravoxel incoherent motion (IVIM) MR imaging for differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs). Forty-five patients with diffuse glioma (age 50.9 ± 20.4 y; 26 males, 19 females) were assessed with IVIM imaging using 13 b-values (0-1000 s/mm(2)) at 3T. The perfusion fraction (f), true diffusion coefficient (D), and pseudo-diffusion coefficient (D*) were calculated by fitting the bi-exponential model. The apparent diffusion coefficient (ADC) was obtained with 2 b-values (0 and 1000 s/mm(2)). Relative cerebral blood volume was measured by the dynamic susceptibility contrast method. Two observers independently measured D, ADC, D*, and f, and these measurements were compared between the LGG group (n = 16) and the HGG group (n = 29). Both D (1.26 ± 0.37 mm(2)/s in LGG, 0.94 ± 0.19 mm(2)/s in HGG; P < .001) and ADC (1.28 ± 0.35 mm(2)/s in LGG, 1.03 ± 0.19 mm(2)/s in HGG; P < .01) were lower in the HGG group. D was lower than ADC in the LGG (P < .05) and HGG groups (P < .0001). D* was not different between the groups. The f-values were significantly larger in HGG (17.5 ± 6.3%) than in LGG (5.8 ± 3.8%; P < .0001) and correlated with relative cerebral blood volume (r = 0.85; P < .0001). Receiver operating characteristic analyses showed areas under curve of 0.95 with f, 0.78 with D, 0.73 with ADC, and 0.60 with D*. IVIM imaging is useful in differentiating HGGs from LGGs. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
    No preview · Article · Aug 2015 · Neuro-Oncology
  • K Tahara · K Yamashita · A Hiwatashi · O Togao · K Kikuchi · M Endo · H Otsuka · Y Oda · H Honda
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    ABSTRACT: We report a case of leiomyosarcoma of the thoracic spine. Primary leiomyosarcoma is a malignant connective tissue tumor originating from smooth muscle cells. Leiomyosarcoma frequently occurs in the uterus, retroperitoneal space, gastrointestinal tract, and deep soft tissues; primary leiomyosarcoma of the bone is rare. The MR imaging including intravoxel incoherent motion (IVIM) imaging findings of the current case indicated a low diffusion coefficient and high blood flow, which were in concurrence with high cell density on histology and increased vascularity by angiography. Although some benign tumors such as osteoblastoma and giant cell tumor would show similar findings on IVIM imaging, these additional imaging features may narrow the differential diagnosis of spinal tumors.
    No preview · Article · Jul 2015
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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.
    No preview · Article · Mar 2015 · Journal of Magnetic Resonance Imaging
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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.
    No preview · Article · Mar 2015 · Gan to kagaku ryoho. Cancer & chemotherapy
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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.
    No preview · Article · Nov 2014 · European Radiology
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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.
    Full-text · Article · Nov 2014 · Brain and Behavior

  • No preview · Conference Paper · Oct 2014
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    ABSTRACT: Aim: To reveal angiographic findings to predict the result of balloon test occlusion (BTO). Methods: The cerebral angiograms of 42 consecutive patients who underwent cerebral angiography including both the Matas and Allcock maneuvers and BTO were retrospectively analyzed. Visualization of the anterior cerebral artery (ACA) and the middle cerebral artery (MCA) by the cross flow on the tested side during the Matas or Allcock maneuver was graded on a 5-point scale. Circle of Willis (COW) anatomy with respect to the presence/absence of a collateral path to reach the tested internal carotid artery (ICA) was classified into four categories. A univariate logistic analysis was used to analyze the associations between each angiographic finding and the BTO result. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for each finding were calculated. Results: Five patients (12%) were BTO-positive and the remaining 37 patients (88%) were BTO-negative. Visualizations of the ACA and MCA as well as the COW anatomy were significantly associated with the BTO result (P = 0.0051 for ACA, P = 0.0002 for MCA, and P < 0.0001 for COW anatomy). In particular, good MCA visualization and the presence of an anterior connection (collateral path to the tested ICA from the contralateral ICA via the anterior communicating artery) in the COW were highly predictive for negative BTO (negative predictive value = 100% for both). Conclusion: A BTO result may be predicted by angiographic findings including ACA/MCA visualization and COW anatomy.
    Preview · Article · Aug 2014
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    ABSTRACT: Purpose To evaluate the diagnostic performance of a double-dose administration of gadolinium for brain metastases at 3 T in a systematic observer test. Materials and Methods 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. Results Compared to the standard dose, the double dose showed higher sensitivity (P
    No preview · Article · Jun 2014 · Japanese journal of radiology
  • A. Hiwatashi · O. Togao · K. Yamashita · K. Kikuchi · H. Honda
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    ABSTRACT: Percutaneous vertebroplasty (PVP) is a minimally invasive procedure that provides pain relief and stability for osteoporotic compression fractures. Balloon kyphoplasty (BKP) is a modification of PVP in which expandable balloons are used to restore height and to create a void in vertebra before cement injection. There are several studies regarding PVP/BKP vs. sham procedures and conservative treatment In this article we review recent studies and introduce some ongoing research.
    No preview · Article · Apr 2014
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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.
    No preview · Article · Feb 2014 · Archives of Oto-Rhino-Laryngology
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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.
    No preview · Conference Paper · Dec 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.
    No preview · Conference Paper · Dec 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.
    No preview · Conference Paper · Dec 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.
    Full-text · Article · Dec 2013 · Neuro-Oncology
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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.
    No preview · Conference Paper · Dec 2013

Publication Stats

1k Citations
207.24 Total Impact Points

Institutions

  • 2007-2015
    • Kyushu University
      • Department of Clinical Radiology
      Hukuoka, Fukuoka, Japan
  • 2006-2009
    • University of Rochester
      • Department of Imaging Sciences
      Rochester, New York, United States
  • 2002-2007
    • University Center Rochester
      • • Department of Imaging Sciences
      • • Department of Radiology
      Rochester, Minnesota, United States