M Miyazaki

Toshiba America Medical Systems, Inc., Tustin, California, United States

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Publications (31)80.61 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Magnetic resonance imaging (MRI) cardiac gated phase contrast (PC) cine techniques have non-invasively shown the effect of the cardiac pulse on cerebrospinal fluid (CSF) movement. Echo planar imaging (EPI) has shown CSF movement as influenced by both cardiac pulsation and respiration. Previously, it has not been possible to visualize CSF movement in response to respiration non-invasively. The present study was undertaken to do so. The effect of respiration on CSF movement was investigated using a non-contrast time-spatial labeling inversion pulse (Time-SLIP) with balanced steady-state free precession (bSSFP) readout. CSF movement was observed in the intracranial compartment in response to respirations in ten normal volunteers. To elucidate the respiration effect, the acquisition was triggered at the beginning of deep inhalation, deep exhalation and breath holding. By employing this respiration-induced spin labeling bSSFP cine method, we were able to visualize CSF movement induced by respiratory excursions. CSF moved cephalad (16.4 +/- 7.7 mm) during deep inhalation and caudad (11.6 +/- 3.0 mm) during deep exhalation in the prepontine cisternal area. Small but rapid cephalad (3.0 +/- 0.4 mm) and caudad (3.0 +/- 0.5 mm) movement was observed in the same region during breath holding and is thought to reflect cardiac pulsations. The Time-SLIP bSSFP cine technique allows for non-invasive visualization of CSF movement associated with respiration to a degree not previously reported.
    Fluids and barriers of the CNS. 12/2013; 10(1):36.
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    ABSTRACT: To visualize the movement of pancreatic juice noninvasively by using an unenhanced magnetic resonance (MR) imaging technique. Institutional review board approval and informed consent were obtained for this study. A flow-out technique of time-spatial labeling inversion pulse (SLIP) technique was applied using both nonselective and selective inversion pulses to label, or tag, pancreatic juice to move out of the region. Ten normal (eight men, two women; age range, 22-61 years; mean age, 35 years) and two pathologic conditions were examined on a commercially available 1.5 Tesla MR imager with quadrature-detected phased-array coils. All images were evaluated by two radiologists to assess depiction of the pancreatic juice movement or pancreatic juice reflux as compared to the pancreatic duct or the common bile duct on MRCP obtained before time-SLIP examination. The tagged pancreatic juice was satisfactory visualized after applying the pulse labeling. Noninvasive visualization of pancreatic juice movement, including normal pancreatic juice movement and reflux from the main pancreatic duct into the common bile duct, was possible by using the unenhanced time-SLIP technique. Noninvasive visualization of pancreatic juice movement is possible by using the unenhanced MR imaging time-SLIP technique.
    Journal of Magnetic Resonance Imaging 12/2011; 35(5):1119-24. · 2.57 Impact Factor
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    ABSTRACT: To evaluate the efficacy of subtracted MR images from two sets of unenhanced three-dimensional (3D) MR angiography data (tag-on and tag-off images) acquired simultaneously during a single breath-hold in assessing the intraportal venous flow distribution to the distal branches from the superior mesenteric vein (SMV) and the splenic vein (SpV). Tag-on and tag-off MR images during a single breath-hold were obtained in 25 normal subjects. Tagging pulse was placed on the SMV or SpV separately to study inflow correlation of tagged blood into the portal vein. On the MR images tagged on the SMV, the mean ratings of visibility of tagged blood flow on the subtracted images were significantly higher (P = 0.016-0.0001) than those on the source images in almost all branches except second-ordered left portal vein (P = 0.096). On the subtracted MR images tagged on SMV, the tramline (16 of the 25 subjects) was the most common distribution pattern of the tagged blood inflow in the main portal vein. Subtracted MR images from two sets of unenhanced 3D MR angiography data (tag-on and tag-off images) acquired simultaneously would be effective to show the blood flow distribution of tagged blood into the portal vein and distal branches from SMV and SpV under the physiological condition without contrast injections.
    Journal of Magnetic Resonance Imaging 05/2009; 29(5):1224-9. · 2.57 Impact Factor
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    ABSTRACT: Institutional review board approval and informed consent were obtained for this study. This study was HIPAA compliant. The purpose of this study was to visualize the movement of cerebrospinal fluid (CSF) noninvasively by using an unenhanced magnetic resonance imaging technique. A time-spatial labeling inversion pulse (SLIP) technique was applied to label, or tag, CSF in a region of interest. The tagged CSF was clearly visualized at inversion times of 1500-4500 msec after pulse labeling in both intracranial and intraspinal compartments. Noninvasive visualization of CSF movement, including bulk and turbulent flow, in normal (n = 7) and altered (n = 2) physiologic conditions was possible by using the unenhanced time-SLIP technique.
    Radiology 12/2008; 249(2):644-52. · 6.34 Impact Factor
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    ABSTRACT: OBJECTIVE: Eighteen healthy persons underwent unenhanced MR angiography with a breath-hold ECG-synchronized 3D half-Fourier fast spin-echo technique to evaluate the visibility of the portal vein and its branches. CONCLUSION: Our results indicated that unenhanced MR angiography with a singlebreath-hold ECG-synchronized 3D half-Fourier fast spin-echo sequence facilitates precise visualization of the anatomic features of the portal vein and its branches without the use of contrast agents.
    American Journal of Roentgenology 08/2008; 191(2):550-4. · 2.90 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 01/2008; · 4.44 Impact Factor
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    ABSTRACT: PurposeTo evaluate the influence of food intake on portal flow using unenhanced magnetic resonance imaging (MRI).Materials and Methods The study population included 29 healthy subjects. A selective inversion recovery tagging pulse was used on the superior mesenteric vein (SMV) and splenic vein (SpV) to study the correlation of tagged blood in the portal vein (PV). MRI was performed before and 60–90 min after a meal.ResultsThe flow signal from the SMV increased in 97% of the subjects after the meal. Before the meal the portal flow was dominated by flow from the SpV in 59% of the subjects, while it was dominated by flow from the SMV in 76% of the subjects after the meal. The most common distribution pattern of the flow signal from the SpV before the meal was in the central part of the main PV (55%), while it was in the left side (45%) after the meal. The most common distribution pattern of the flow signal from the SMV was in the bilateral sides of the main PV both before and after the meal (62%).Conclusion This technique shows potential for evaluating pre- and postprandial alterations of flow from the SpV and SMV in the PV under physiological conditions. J. Magn. Reson. Imaging 2005. © 2005 Wiley-Liss, Inc.
    Journal of Magnetic Resonance Imaging 09/2005; 22(4):527 - 533. · 2.57 Impact Factor
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    ABSTRACT: The dilatation of the thoracic duct was previously demonstrated in liver cirrhosis by lymphangiography, endoscopic ultrasound, and at autopsy. The evaluation of the morphologic change of the thoracic duct may be important in assessing the altered lymphodynamics in liver cirrhosis. The objectives of this study were to determine which combination of posture and breathing phase during noncontrast-enhanced magnetic resonance lymphography (MRL) provided the clearest images, and to evaluate the morphologic changes in the thoracic duct in healthy volunteers and patients with liver disease and malignancy. Prospective study. Community general hospital. Design and subjects: Twenty-three healthy volunteers and 113 patients underwent the MRL examination using a three-dimensional, half-Fourier, fast spin echo sequence on a 1.5-T, whole-body magnetic resonance system. The appropriate posture and breathing phase of MRL to obtain the best visualization was first determined by trial on 14 healthy volunteers. Morphologic changes of the thoracic ducts were evaluated in 23 healthy volunteers including the 14 healthy volunteers for the first trial and 113 patients using this appropriate method. The width of the thoracic ducts in both patients and volunteers was measured. Measurements and results: MRL with respiratory gating in the supine position depicted the thoracic duct well and was the most comfortable for the subjects. In 82 of 113 patients (72.6%), the thoracic ducts were entirely visualized from the diaphragm level to the subclavian region. The remaining 31 patients had ducts that could not be entirely visualized due to sections or short lengths that were obscured. The maximum diameter was 3.74 +/- 0.81 mm in all healthy volunteers, 6.98 +/- 2.77 mm in alcoholic cirrhosis, 4.12 +/- 1.51 mm in nonalcoholic cirrhosis, 3.76 +/- 1.10 mm in malignancy, and 3.60 +/- 0.80 mm in chronic hepatitis (mean +/- SD). The diameter in alcoholic cirrhosis was significantly greater than in other groups (p < 0.01). Respiratory gating in the supine position is the best MRL method for acquiring the clearest images. This may be a good method of detecting morphologic changes in the thoracic duct. The patients with alcoholic cirrhosis showed a greater thoracic duct diameter than other groups.
    Chest 01/2004; 124(6):2136-42. · 5.85 Impact Factor
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    ABSTRACT: The authors evaluated a nonenhanced magnetic resonance (MR) angiographic technique that allows separation of arteries from veins. In 15 healthy subjects, peripheral MR angiography was performed with readout flow-spoiled gradient pulses in electrocardiography-triggered three-dimensional half-Fourier fast spin-echo MR imaging. Appropriate flow-spoiled gradient pulses were measured and applied in the three-dimensional acquisition to differentiate arteries and veins in the peripheral vasculature. Subtraction of the diastolic bright-blood arteries from the systolic black-blood arteries allowed visualization of the arteries by cancelling the veins, which are constantly depicted as bright blood throughout the cardiac cycle. Stronger flow-spoiled gradient pulses improved the depiction of slow-flow arteries even in the distal foot and hand vessels.
    Radiology 07/2003; 227(3):890-6. · 6.34 Impact Factor
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    ABSTRACT: We investigated temporal MR signal changes in the peripheral lung and proximal pulmonary vessels during the entire cardiac cycle in order to evaluate the characteristics of the diastolic-systolic subtraction method in the lung. In eight healthy volunteers free of lung diseases, changes in the MR signal during one breath-hold were investigated with the multiple ECG-triggered half-Fourier single-shot fast-spin echo (SS-FSE) technique. The signal intensity-time course curve in the lung showed that biphasic signals decreased 20% to 47% at systole and 5% to 33% at mid-diastole, measured against the maximum signals at late diastole. This signal decrease in the peripheral lung was correlated to that in the proximal pulmonary vessels during an entire cardiac cycle (r=0.667 to 1.000). The best visualization of the lung was obtained at late diastole, when the intra-vascular flow in the lung was expected to be stagnant. Compared with the late diastolic SS-FSE images, the late diastolic-systolic subtracted SS-FSE images improved the signal-to-noise ratio in the lung as well as the signal-intensity ratio of the peripheral lung to surrounding tissues. Although the flow-induced signal dephasing in the lung was completely unavoidable and its amount was unpredictable even at late diastole, the diastolic-systolic subtracted SS-FSE images showed the relative differences in flow alteration during the cardiac cycle between the images at diastole and those at systole. The main characteristic of diastolic-systolic subtracted SS-FSE was the enhancement of visibility of cardiac-dependent signal changes in the lung due to the alteration in pulsatile flow.
    Magnetic Resonance in Medical Sciences 12/2002; 1(3):137-47. · 0.75 Impact Factor
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    ABSTRACT: A noncontrast electrocardiography (ECG)-gated, fast-spin-echo magnetic resonance imaging was applied to noninvasively define perfusion impairments in pulmonary embolic and airway obstruction dog models. Two-phase ECG-gated lung images of the minimal lung signal intensity during systole and maximal signal intensity during diastole were acquired by using optimized R-wave triggering delay times in seven dogs anesthetized with pentobarbital sodium before, soon after, and 2 mo after embolization with enbucrilate and in another eight dogs before and after bronchial occlusion with balloon catheters, in combination with a gadolinium diethylenetriaminepentaacetic acid-enhanced dynamic study. An ECG-gated subtraction image between the two-phase lung images provided a uniform but gravity-dependent perfusion map in normal lungs. Furthermore, it defined all 13 variable-size perfusion deficits associated with pulmonary embolism and the dynamically decreased perfusion with time after bronchial occlusion in all the airway obstruction models. These results were consistent with contrast-enhanced pulmonary arterial perfusion phase images. This noncontrast imaging could be equivalent to a contrast-enhanced dynamic study in the definition of regionally impaired pulmonary arterial perfusion in pulmonary embolism and airway obstruction.
    Journal of Applied Physiology 07/2002; 92(6):2439-51. · 3.48 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the intraportal blood flow distribution from splenic and superior mesenteric veins with an unenhanced MR angiographic technique using single breath-hold ECG-triggered three-dimensional (3D) half-Fourier fast spin-echo sequence and selective inversion-recovery tagging pulse. Seventeen healthy volunteers were included in this prospective study. After obtaining regular single breath-hold ECG-triggered 3D half-Fourier fast spin-echo images without applying a tagging pulse, we placed the selective inversion-recovery tagging pulse on the superior mesenteric vein (TAG-A), the splenic vein (TAG-B), or on both (TAG-C) to study the inflow correlation of tagged or marked blood into the portal vein. MR images were evaluated subjectively by three reviewers. On MR images obtained using the TAG-A pulse to suppress the signal flow from the superior mesenteric vein into the portal vein, the most common pattern of signal loss was observed on the right half of the main portal vein (8/17 subjects). Conversely, on the MR images obtained using the TAG-B pulse, signal loss of the left half of the main portal vein was the most common pattern (11/17 subjects). Signal reduction from the splenic venous flow in the left portal vein was significantly greater than that from the superior mesenteric venous flow (p<0.05). The unenhanced MR angiographic technique using single breath-hold ECG-triggered 3D half-Fourier fast spin echo with selective inversion-recovery tagging pulse has the potential to assess the intraportal blood flow distribution from the splenic and superior mesenteric veins.
    American Journal of Roentgenology 02/2002; 178(2):343-8. · 2.90 Impact Factor
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    ABSTRACT: The efficacy of the nonenhanced magnetic resonance angiography (MRA) technique known as fresh-blood imaging (FBI), using electrocardiograph (ECG)-triggered 3D half-Fourier fast spin-echo (FSE), was evaluated for the detection and characterization of aortic diseases. Seventy-five consecutive patients with aortic disease underwent the FBI examination on a 1.5-T clinical imager. The results showed that the FBI technique permits clear visualization of aortic diseases, and the vessel branches and their relationship, which provides valuable information. Therefore, the nonenhanced FBI technique is appropriate to use for screening purposes.
    Journal of Magnetic Resonance Imaging 09/2001; 14(2):113-9. · 2.57 Impact Factor
  • 3rd International Symposium of the Japanese Society of Magnetic Resonance in Medicine JSMRM; 01/2001
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    ABSTRACT: A non-contrast-enhanced three-dimensional (3D) magnetic resonance angiography (MRA) technique, which acquires images in a reasonably short scanning time and requires no contrast agent, is developed. An electrocardiographically (ECG) synchronized 3D half-Fourier fast spin-echo (FSE) technique with an appropriate ECG delay time for every slice encoding in 3D terms was used to examine the thoracic and iliac regions in 16 healthy volunteers at both 0.5 and 1.5 T. Prior to each 3D fresh blood imaging (FBI) experiment, an ECG preparation (ECG-prep) scan was acquired, and an appropriate ECG triggering time was selected for 3D FBI acquisition to optimize visualization of the vessel of interest. In the thoracic and abdominal regions, good-quality 3D MRA images were obtained. Furthermore, the weighted subtraction of two images in different phases provides contrast enhancement between arteries and veins.
    Journal of Magnetic Resonance Imaging 12/2000; 12(5):776-83. · 2.57 Impact Factor
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    ABSTRACT: A non-contrast-enhanced three-dimensional (3D) magnetic resonance angiography (MRA) technique, which acquires images in a reasonably short scanning time and requires no contrast agent, is developed. An electrocardiographically (ECG) synchronized 3D half-Fourier fast spin-echo (FSE) technique with an appropriate ECG delay time for every slice encoding in 3D terms was used to examine the thoracic and iliac regions in 16 healthy volunteers at both 0.5 and 1.5 T. Prior to each 3D fresh blood imaging (FBI) experiment, an ECG preparation (ECG-prep) scan was acquired, and an appropriate ECG triggering time was selected for 3D FBI acquisition to optimize visualization of the vessel of interest. In the thoracic and abdominal regions, good-quality 3D MRA images were obtained. Furthermore, the weighted subtraction of two images in different phases provides contrast enhancement between arteries and veins. J. Magn. Reson. Imaging 2000;12:776–783. © 2000 Wiley-Liss, Inc.
    Journal of Magnetic Resonance Imaging 10/2000; 12(5):776 - 783. · 2.57 Impact Factor
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    ABSTRACT: The objective of this study was to examine the relation of tumor vascularity on magnetic resonance imaging (MRI) with differential diagnosis malignant from benign lesions and tumor invasiveness in breast carcinoma. Forty-nine patients with breast cancer or benign lesion (median 49 yrs) were examined with dynamic MRI. Scanning of the entire breast was performed at 1.5 T with a three-dimensional fast spin echo sequence, using an original polarity altered spectral and spatial selective acquisition (PASTA) technique for fat suppression. Subsequently 0.1 mmol/Kg Gd-DTPA was administered and 3-6 images were obtained. The presence or absence of intratumoral, marginal and peritumoral vascularity on MRI was recorded. The excised specimen was histopathologically examined for the size of lesion, the presence and extent of local invasion. Tumor size on MRI correlated closely with the size at morphologic examination (r = 0. 96). Intratumoral (p = 0.04), marginal (p = 0.05) and peritumoral vascularity (p = 0.01) were less common in benign than in malignant lesions. Among the latter, intratumoral (p = 0.01) and marginal (p = 0.03) vascularity were more common in invasive carcinomas than in DCIS. In the subset of invasive carcinomas (n = 31); however, the tumors exhibiting intratumoral vascularity were markedly larger (p = 0.03). The presence of intratumoral and marginal vascularity on MRI can help predict both the differential diagnosis malignant from benign lesions and the presence tumor invasion in breast carcinomas.
    Magnetic Resonance Imaging 10/2000; 18(7):807-13. · 2.06 Impact Factor
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    K Fukui, S Miyachi, M Kato, M Miyazaki
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    ABSTRACT: We report a case of acute subdural haematoma in traumatic carotid-cavernous fistula. The patient had a history of head trauma four years ago. Postoperative study revealed CCF of dominant posterior drainage with giant pseudoaneurysm. Thereafter endovascular treatment using detachable balloons and detachable platinum micro-coils made successful occlusion of the fistula preserving the ICA.
    Interventional Neuroradiology 06/2000; 6(2):147-52. · 0.77 Impact Factor
  • 28th Meeting of the Japanese Journal of Magnetic Resonance in Medicine JMRM; 01/2000
  • 12th International Workshop on Magnetic Resonance Angiography; 01/2000

Publication Stats

402 Citations
80.61 Total Impact Points

Institutions

  • 1998–2011
    • Toshiba America Medical Systems, Inc.
      Tustin, California, United States
  • 2009
    • Kawasaki Medical University
      Kurasiki, Okayama, Japan
  • 2002
    • Yamaguchi University
      • Division of Radiology
      Yamaguti, Yamaguchi, Japan
  • 2000
    • Mitsubishi Nagoya Hospital
      Nagoya, Aichi, Japan
    • Nagoya University
      • Division of Radiology
      Nagoya-shi, Aichi-ken, Japan
  • 1999
    • Toho University
      • Department of Radiology
      Edo, Tōkyō, Japan