Nobuko Tokunaga

Ehime Prefectural Central Hospital, Matuyama, Ehime, Japan

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Publications (4)4.44 Total impact

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    ABSTRACT: The aim of this study was to analyze microvas-cularity after reperfused acute myocardial infarction (AMI) using the maximum slope method of contrastenhanced cardiac magnetic resonance imaging (CMR). CMR and resting (201)T1 single photon emission computed tomography (SPECT) images were obtained in 30 consecutive patients after reperfused AMI and 10 controls. After bolus injection of gadolinium diethylenetriamine pentaacetic acid, first-pass CMR images were obtained using the True-FISP sequence. Time-intensity curves were generated by measuring the signal intensity in the myocardium and left ventricle. The arterial input function was obtained from the left ventricular time-intensity curve. On the basis of the maximum slope method, the microvascular index (MVI) was calculated by dividing the maximum initial upslope of the myocardium by the initial upslope of the left ventricle. The MVI was significantly lower in the segments related to the occluded coronary artery. MVIs in segments with (201)Tl uptake of 50%-59% of peak were significantly lower than in those with (201)Tl uptake of 60%-69%. MVIs in segments with (201)Tl uptake of <50% of peak were significantly lower than in those with (201)Tl uptake of 50%-59%. This study presents a method that directly assesses microvascularity after reperfused AMI.
    No preview · Article · Jun 2008 · Radiation Medicine
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    ABSTRACT: We introduce a new method that uses high-resolution myocardial perfusion images with 64-slice CE-MDCT and we investigate the performance of the new method in terms of detecting myocardial ischemia. CT perfusion images demonstrated that myocardial ischemia is characterized by transient hypoperfusion at systole and reperfusion at diastole. CT perfusion imaging has potential as a non-invasive method for detecting myocardial ischemia at rest.
    No preview · Article · Jan 2008
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    ABSTRACT: The purpose of this study is to evaluate reperfused acute myocardial infarction with late enhancement (LE) pattern on contrast-enhanced magnetic resonance imaging compared with myocardial single photon emission computed tomography (SPECT) images. Magnetic resonance and 201Tl and 99mTc-hydroxymethylenediphosphonate SPECT images were obtained from 40 patients within 6 days of reperfused myocardial infarction. We assessed the myocardial LE pattern using the true fast imaging with steady-state free precession sequence after the injection of Gd-DTPA. Patients were classified into 3 groups: group 1 included patients with localized endocardial enhancement; group 2, patients with transmural enhancement; and group 3, patients with LE and a residual defect. There were 9 patients (23%) in group 1, 15 (38%) in group 2, and 15 (38%) in group 3. In 1 patient, LE was not detected (3%). The %201Tl uptake for the infarcted area was 60.7 +/- 7.2 (mean +/- SD) for group 1, 49.5 +/- 12.3 (P < 0.05 vs. group 1) for group 2, and 36.9 +/- 8.2 (P < 0.0001 vs. group 1, P = 0.005 vs. group 2) for group 3. An overlap pattern of 201Tl and 99mTc was observed in 9 of the group 1 patients (100%) and 9 of the group 2 patients (60%), but was not evident in group 3 (0%). LE with residual defect is an important indicator of microvascular obstruction after reperfusion therapy.
    No preview · Article · Nov 2007 · Investigative Radiology
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    ABSTRACT: LEARNING OBJECTIVES In this exhibit, we will present the relationship between crossed cerebellar diaschisis (CCD) and cerebral perfusion reserve (CPR) by acetazolamide (ACZ) test and SPECT. To learn (1) how to distinguish cause of CBF reduction by ACZ test and SPECT without PET study, (2) the changes of CPR by surgery in representative cases. ABSTRACT In management of patients with occlusive cerebrovascular diseases (CVDs), it is important to distinguish cerebral blood flow (CBF) reduction caused by reduced blood supply (misery perfusion) from those caused by reduced metabolic demand (matched perfusion). We studied 20 patients with unilateral occlusive CVDs, who had reduced CBF but no cortical abnormalities. Regional CBF and CPR were quantitatively measured by I-123 IMP (IMP) split dose method. In 8 patients with CCD, there was no difference in the CPR between the affected and non-affected cerebral hemispheres (52.7�29.8 vs. 63.1�19.6%, ns) in patients with CCD. However, in 12 patients without CCD the CPR in the affected cerebral hemisphere was significantly decreased (16.7�22.1 vs. 50.5�24.6%, p<0.05). After surgery, the reduced CPR increased in patients without CCD, while it didn?t change in patients with CCD. In this CBF measurement using SPECT and ACZ test, CCD is useful to estimate the cause of CBF reduction.
    No preview · Conference Paper · Nov 2004