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Journal of Nippon Medical School 01/2013; 80(1):2-3.
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ABSTRACT: Background
Two-dimensional (2D) Look-Locker MRI technique can identify myocardial fibrosis, but cannot cover the whole left ventricle during a single scan.PurposeTo develop breath-hold three-dimensional (3D) Look-Locker MRI for the evaluation of postcontrast myocardial and blood T1 values and myocardial scarring in the left ventricle.Material and MethodsA phantom and 24 patients with myocardial diseases underwent gadolinium-enhanced 2D and 3D Look-Locker MRI using a 1.5-T unit. We compared the T1 value of the phantom and the values of the myocardium and blood in the patients between the two Look-Locker MRI sequences. In the patient study, the scan ordering of the two Look-Locker MRI was selected randomly. We also assessed the ability of the 3D imaging to detect myocardial scarring that was confirmed by late gadolinium enhancement MRI.ResultsThe phantom study showed a good agreement for the T1 value between 2D and 3D Look-Locker MRI. There were no significant differences in the myocardial T1 values after contrast between 2D and 3D Look-Locker MRI or in the T1 values between the two imaging slices on the 3D Look-Locker MRI (P > 0.10). A better agreement for the myocardial T1 values was found when the 3D Look-Locker imaging was performed first. The T1 values for blood were affected by the scan order (P < 0.05). The 3D Look-Locker MRI showed myocardial scarring with a shorter T1 value (290.4 ± 62.7 ms) than those for unscarred myocardium (360.8 ± 30.3 ms).Conclusion
Three-dimensional Look-Locker MRI may precisely estimate the postcontrast myocardial and blood T1 values for the entire left ventricle during a single scan.
Acta Radiologica 11/2012; · 1.37 Impact Factor
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ABSTRACT: PURPOSE: To evaluate the usefulness of magnetic resonance imaging (MRI) for detection and quantification of myocardial damage related to clinical phases and cardiac function during eosinophilic myocarditis. MATERIALS AND METHODS: Four eosinophilic myocarditis patients received seven MRI studies. The left ventricular myocardium was divided into 48 layers, and we quantified the extent of abnormal intensity detected by T2-weighted or delayed enhancement MRI relative to the clinical phase and global cardiac function. RESULTS: T2-weighted imaging detected extensive myocardial hyperintensity during the acute phase of eosinophilic myocarditis. Diffuse myocardial delayed enhancement was observed in one patient during the acute phase, but not in the other. Little or no hyperintensity was detected by T2-weighted imaging or myocardial delayed enhancement during the convalescent phase. The extent of hyperenhancing myocardial layers was inversely correlated with the ejection fraction (EF) (r = -0.87). CONCLUSION: MRI can evaluate the presence and extent of myocardial damage related to the clinical phases and EF during eosinophilic myocarditis.
Japanese journal of radiology 09/2012; · 0.65 Impact Factor
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ABSTRACT: Gastric schwannoma is a rare tumor that accounts for only 0.2 % of all gastric tumors. We report a case of gastric schwannoma that underwent computed tomography (CT), magnetic resonance imaging (MRI), and [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET), and its histological confirmation was acquired. Gastric schwannoma showed high intensity on T2-weighted and diffusion-weighted MRI and high maximum standardized uptake on [(18)F]-FDG-PET. Lymphadenopathy close to the tumor was also found. Although diffusion-weighted MRI, [(18)F]-FDG-PET, and the presence of lymphadenopathy could suggest malignant tumors, the detail interpretation of the other CT and MRI findings may give a clue for the diagnosis of gastric schwannoma.
Japanese journal of radiology 06/2012; 30(7):602-5. · 0.65 Impact Factor
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ABSTRACT: Asymmetric septal hypertrophic cardiomyopathy (ASH) is the common phenotype of hypertrophic cardiomyopathy (HCM). We sought to classify ASH using magnetic resonance imaging (MRI) and to determine whether the MRI classification of ASH is related to the presence of risk factors for HCM. Ninety-three patients with ASH underwent cine and delayed-enhancement MRI. The ASH was classified morphologically using cine MRI at end-diastole. We evaluated the association between the MRI findings and the presence of risk factors in the ASH. The ASH was classified into three subtypes by MRI: contiguous subtype showing various clinical and MRI features (57%), sigmoid subtype (29%) with fewer risk factors, and reverse-curve subtype (14%) in younger patients with the larger myocardial mass and delayed-enhancement, which were significantly related to the risk factors. MRI was used to classify ASH into three subtypes, which might be related to the presence of risk factors.
The international journal of cardiovascular imaging 03/2012; · 2.15 Impact Factor
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Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:W40. · 3.72 Impact Factor
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Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P152. · 3.72 Impact Factor
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Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P302. · 3.72 Impact Factor
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ABSTRACT: To compare the antitumor efficacy and safety of transcatheter arterial chemoembolization (TACE) by epirubicin suspension (epirubicin suspension: epirubicin-iodized oil mixture without solution) to that by epirubicin emulsion (epirubicin emulsion: epirubicin-iodized oil mixture with solution), the efficacy of treatment by administration of either an epirubicin suspension or emulsion was examined in an animal model. Changes in plasma epirubicin concentration were compared over 24 h immediately after treatment, and enhanced ultrasonographic and histopathological analysis subsequently conducted 7 days after treatment to determine the growth ratio and proportion of viable tumor cells. The growth ratio and proportion of viable tumor cells were found to be significantly lower in the suspension group than in the emulsion group while the plasma epirubicin concentration was found to be significantly higher in the suspension group than in the emulsion group. These results indicate that administration of an epirubicin suspension is a superior form of TACE compared to that of administration of an epirubicin emulsion.
TheScientificWorldJOURNAL 01/2012; 2012:961986. · 1.66 Impact Factor
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ABSTRACT: The purpose of this paper is to describe imaging techniques and findings of T2-weighted magnetic resonance imaging (MRI) of edema in myocardial diseases. T2-weighted cardiac MRI is acquired by combining acceleration techniques with motion and signal suppression techniques. The MRI findings should be interpreted based on coronary artery supply, intramural distribution, and comparison with delayed-enhancement MRI. In acute myocardial diseases, such as acute myocardial infarction and myocarditis, the edema is larger than myocardial scarring, whereas the edema can be smaller than the scarring in some types of nonischemic cardiomyopathy, including hypertrophic cardiomyopathy. T2-weighted MRI of edema identifies myocardial edema associated with ischemia, inflammation, vasculitis, or intervention in the myocardium and provides information complementary to delayed-enhancement MRI.
TheScientificWorldJOURNAL 01/2012; 2012:194069. · 1.66 Impact Factor
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ABSTRACT: Sarcoidosis is a multisystem disorder of unknown etiology that involves multiple organs. Computed tomography is the first-line imaging modality for diagnosing sarcoidosis because of its capacity to detect hilar lymphadenopathy and pulmonary lesions. Magnetic resonance (MR) imaging provides good soft tissue contrast that is useful for detecting sarcoidosis in some body parts, including skeletal muscle. Signal intensity on pre- and postcontrast T(1)- and T(2)-weighted imaging may reflect disease activity and the pathological appearance of sarcoidosis. In this review, we demonstrate these conventional MR imaging findings of hepatosplenic and muscular sarcoidosis and describe the usefulness of diffusion-weighted imaging for detecting sarcoidosis.
Magnetic Resonance in Medical Sciences 01/2012; 11(2):83-9. · 0.97 Impact Factor
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ABSTRACT: The aim of this study was to determine whether non-contrast-enhanced magnetic resonance imaging (MRI) can detect three levels of renal impairment by evaluating the differences and agreement with (99m)Tc-diethylenetriamine pentaacetic acid (DTPA) renography.
A total of 28 patients with kidney disease were enrolled in the study. MRI findings, including visual corticomedullary differentiation (CMD) on T1- and T2-weighted imaging (T1WI, T2WI), cortical irregularity, the number of renal cysts, and the volume of the kidney, were evaluated for individual kidneys and pairs of kidneys. The differences and agreement between MRI findings and the three levels of renal impairment based on the glomerular filtration rate (GFR) measured using (99m)Tc-DTPA renography were analyzed.
All MRI findings except the number of renal cysts in pairs of kidneys were consistent with the patient's classification. The agreement between the patient's classifications based on GFR and that based on the visual CMD on T1WI and T2WI was almost perfect or substantial in both individual kidneys and pairs of kidneys.
Non-contrast-enhanced MRI was capable of distinguishing three levels of renal function, including serious renal impairment.
Japanese journal of radiology 07/2011; 29(6):378-85. · 0.65 Impact Factor
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ABSTRACT: Hypertrophic cardiomyopathy (HCM) is reported to show patchy midwall myocardial hyperenhancement on delayed-enhancement magnetic resonance imaging (DE-MRI). The intramural distribution of myocardial hyperenhancement and its correlation with clinical symptoms, ventricular arrhythmias, and cardiac function have not been described forsymptomatic apical HCM.
To evaluate the features and significance of myocardial hyperenhancement on DE-MRI insymptomatic apical HCM.
Thirteen patients with symptomatic apical HCM and their 65 apical segments were investigated. Myocardial hyperenhancement and regional and global functional parameters were determined with MRI. We investigated the intramural distribution and frequencies of this myocardial hyperenhancement and compared them with the patients' clinical symptoms, the presence of ventricular arrhythmias, and cine MRI.
Eight (61.5%) patients with symptomatic apical HCM displayed apical myocardial hyperenhancement, and 22 (33.8%) of the 65 apical segments examined showed myocardial hyperenhancement. Of the myocardial hyperenhancement observed, 81.8% showed a subendocardial pattern.The hyperenhanced apical myocardium had a lower percentage of systolic myocardial thickening, and was associated with serious symptoms (e.g. syncope) and ventricular arrhythmias.
Patients with symptomatic apical HCMshowed myocardial hyperenhancement involving the subendocardial layer, which might be related to regional systolic dysfunction, serious clinical symptoms, and ventricular arrhythmias.
Acta Radiologica 04/2011; 52(6):613-8. · 1.37 Impact Factor
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ABSTRACT: The blood flow patterns of chronic thoracic aortic dissection are complicated, and their clinical significance remains unknown. We evaluated the technical and clinical potentials of time-resolved 3-dimensional (3D) magnetic resonance (MR) velocity mapping for assessing these patterns.
We used data collected from time-resolved 3D phase-contrast MR imaging of 16 patients with chronic thoracic aortic dissection to generate time-resolved 3D MR velocity mapping that included 3D streamline and path line. We investigated blood flow patterns of this disease in the mapping and compared them with the morphological changes of the patent false lumen.
Time-resolved 3D MR velocity mapping visualized rapid flow at the entry and in the true lumen immediately distal to the entry. We observed slower helical or laminar flow in the patent false lumen. In patients with disease progression, slower helical flow following rapid entry jet collided with the outer wall of the false lumen and was also observed in a growing ulcer-like projection.
We showed the potential of time-resolved 3D MR velocity mapping for visualizing pathologic flow patterns related to chronic thoracic aortic dissection.
Magnetic Resonance in Medical Sciences 01/2011; 10(2):93-9. · 0.97 Impact Factor
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ABSTRACT: Takayasu arteritis is an inflammatory disease of unknown etiology that involves the aorta, its major branches, and the pulmonary artery. We describe three patients with Takayasu arteritis who showed abnormal velocity profile of the thoracic aorta and supra-aortic arteries on time-resolved three-dimensional (3D) phase-contrast MR imaging and velocity mapping techniques. Compared with two comparative subjects, velocity reduction was observed in these arteries. The velocity reduction was prominent along the thickened arterial wall, even with normal luminal caliber, and the highest velocity was observed on the contralateral side. In one patient, the arterial flow velocity and its profile at systole were partly improved after the treatment. The time-resolved 3D velocity mapping visualized the changes in the blood velocity profile at systole in Takayasu arteritis.
Journal of Magnetic Resonance Imaging 06/2010; 31(6):1481-5. · 2.70 Impact Factor
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ABSTRACT: To assess the myocardial damage in hypertrophic cardiomyopathy (HCM) using contrast-enhanced myocardial T1-weighted scout (Look-Locker) magnetic resonance imaging (MRI).
Twenty-three patients with HCM and seven comparative patients without known HCM serving as controls underwent cine, contrast-enhanced myocardial T1-weighted scout and delayed-enhancement MRI using a 1.5T unit. Intervals of null points between myocardium and blood were compared among hyperenhancing and nullified myocardium of HCM and the normal myocardium. The relationship between these myocardial patterns and global cardiac functions was analyzed in HCM.
The hyperenhancing myocardium, dense myocardial fibrosis in HCM had null points significantly shorter than blood, normal myocardium, and nullified myocardium of HCM (P < 0.0001). The number of hyperenhancing myocardial segments correlated with the ejection fraction (P = 0.045). The nullified myocardium of HCM showed shorter intervals of the null points between myocardium and blood than did the normal myocardium, indicating the dispersed myocardial fibrosis (P = 0.0032). The interval of null points between the nullified myocardium and blood showed a significant correlation with the increase in myocardial mass in HCM (P = 0.034).
Contrast-enhanced myocardial T1-weighted scout imaging has the potential for showing dispersed myocardial damage leading to increased myocardial mass in HCM, while the dense myocardial fibrosis correlated with reduced ejection fraction.
Journal of Magnetic Resonance Imaging 10/2009; 30(4):778-84. · 2.70 Impact Factor
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ABSTRACT: To evaluate the feasibility of a respiratory-compensated three-dimensional (3D) T1-weighted k-space segmented gradient-echo imaging sequence with radial data sampling for noncontrast-enhanced 3D magnetic resonance (MR) aortography of the thorax at 3.0 T.
Twenty-two subjects, including healthy volunteers (n = 6) and patients with suspected diseases of the thoracic aorta (n = 16), underwent noncontrast-enhanced 3D MR aortography at 3.0 T acquired using a navigator- or respiratory-gated 3D T1-weighted k-space segmented gradient-echo imaging sequence with radial data sampling (TR, 4.8 milliseconds; TE, 1.5 milliseconds; flip angle, 20 degrees; spatial resolution 0.66 x 0.76 x 5.6-6.4 mm) in the sagittal oblique imaging plane. ECG gating, fat-suppression, and T2-prepared pulses were employed. The vascular contrast of the thoracic aorta and the contrast ratio between the aorta and the superior vena cava or pulmonary artery were compared between the noncontrast-enhanced 3D MR aortography and transverse two-dimensional (2D) steady-state free precession. Image quality of the noncontrast-enhanced 3D MR aortography was rated on a 4 point scale (1, nondiagnostic, to 4, diagnostic and excellent image quality).
The noncontrast-enhanced 3D MR aortography provided vascular contrast of the thoracic aorta comparable to, and contrast ratio between the aorta and superior vena cava higher than, those of 2D steady-state free precession. The mean score of image quality of the noncontrast-enhanced 3D MR aortography was 3.0 (diagnostic with no or few artifact), and some major branch arteries were visualized by this imaging.
Respiratory-compensated 3D T1-weighted k-space segmented gradient-echo imaging with radial data sampling are feasible for the noncontrast-enhanced 3D MR aortography of the thorax at 3.0 T.
Investigative radiology 08/2009; 44(9):548-52. · 4.85 Impact Factor
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ABSTRACT: To assess the feasibility of free-breathing high-spatial-resolution delayed contrast-enhanced three-dimensional (3D) viability magnetic resonance imaging (MRI) at 3.0 T for the detection of myocardial damages.
Twenty-five patients with myocardial diseases, including myocardial infarction and cardiomyopathies, were enrolled after informed consent was given. Free-breathing 3D viability MRI with high spatial resolution (1.5 x 1.25 x 2.5 mm) at 3.0 T, for which cardiac and navigator gating techniques were employed, was compared with breath-hold two-dimensional (2D) viability imaging (1.77 x 1.18 x 10 mm) for assessment of contrast-to-noise ratio (CNR) and myocardial damage.
Free-breathing 3D viability imaging was achieved successfully in 21 of the 25 patients. This imaging technique depicted 84.6% of hyperenhancing myocardium with a higher CNR between hyperenhancing myocardium and blood and with excellent agreement for the transmural extension of myocardial damage (k = 0.91). In particular, the 3D viability images delineated the myocardial infarction and linear hyperenhancing myocardium, comparable to the 2D viability images.
Free-breathing high-spatial-resolution delayed contrast-enhanced 3D viability MRI using 3.0 T was feasible for the evaluation of hyperenhancing myocardium, as seen with myocardial infarction and cardiomyopathies.
Journal of Magnetic Resonance Imaging 12/2008; 28(6):1361-7. · 2.70 Impact Factor
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ABSTRACT: To determine the appropriate dose of contrast medium for moving-table MR angiography (MT-MRA) from the abdominal aorta to the ankle by comparing visualization with different doses of meglumine gadopentetate (Gd-DTPA) administered in crossover fashion to normal volunteers.
Twelve healthy adults underwent imaging after crossover administration of 0.1 and 0.2 mmol/kg of Gd-DTPA in random order. Continuous MT-MRA was performed with a fast 3D spoiled gradient echo sequence without parallel imaging technique. Visualization was evaluated in a total of 252 arteries by three blinded readers who independently rated arterial visualization using a 5-grade scale. Signal intensity was determined and the blood concentration of Gd-DTPA was estimated.
Arterial visualization in the lower leg region was significantly better with a dose of 0.2 mmol/kg than with 0.1 mmol/kg (P<0.001). For all regions assessed the estimated blood Gd-DTPA level was significantly higher with 0.2 mmol/kg than with 0.1 mmol/kg (abdominal aorta, P=0.030; superficial femoral artery, P<0.001; posterior tibial artery, P=0.039). The vascular signal enhancement ratio and artery-to-muscle signal ratio were significantly higher in the upper leg and lower leg regions at 0.2 mmol/kg.
With continuous MT-MRA imaging from the abdomen to the ankle in normal volunteers, better arterial visualization and superior contrast were achieved with 0.2 mmol/kg of Gd-DTPA.
Journal of Magnetic Resonance Imaging 09/2008; 28(3):783-90. · 2.70 Impact Factor
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ABSTRACT: To assess the usefulness of non-contrast-enhanced MR angiography using cardiac and navigator-gated magnetization-prepared three-dimensional (3D) steady-state free precession (SSFP) imaging for the diagnosis of diseases of the thoracic aorta.
Twenty-two patients with diseases of the thoracic aorta were examined using a 1.5 Tesla unit. Non-contrast-enhanced MR angiography was done using parasagittal 3D SSFP combined with cardiac-gating and k-space weighted navigator-gating techniques, using T2-prepared and fat-suppression pulses. Imaging quality and the diagnostic capability of this technique were compared with the imaging quality of 2D SSFP or contrast-enhanced 3D MR angiography and with final diagnoses.
Non-contrast-enhanced 3D MR angiography provided signal-to-noise and contrast-to-noise ratios of the thoracic aorta comparable to non-contrast-enhanced 2D or contrast-enhanced 3D MR angiography (P > 0.17). This imaging technique gave accurate diagnoses in 19 of the 22 patients.
Non-contrast-enhanced MR angiography using cardiac and navigator-gated magnetization-prepared 3D SSFP technique was useful for the diagnosis of diseases of the thoracic aorta.
Journal of Magnetic Resonance Imaging 03/2008; 27(3):504-9. · 2.70 Impact Factor
