Tetsuji Yamaguchi

Nagasaki University Hospital, Nagasaki, Nagasaki, Japan

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Publications (12)22.11 Total impact

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    ABSTRACT: PURPOSE The aim of this prospective study was to evaluate the utility of magnetic resonance imaging (MRI) findings in differentiating progressive massive fibrosis (PMF) from lung cancer in patients with pneumoconiosis. METHOD AND MATERIALS Thirty two pulmonary lesions, suspected the possibility of lung cancer on CT, in 24 patients with pneumoconiosis were evaluated. The diagnosis of PMF was made based on the signal intensity of the lesions on T2 weighted image (T2WI) and the enhancement pattern of the lesions by dynamic contrast-enhanced studies on MRI. These MRI findings were correlated with the histological findings. RESULTS 17 lesions showed hypo-intensity on T2WI; 16 of 17 lesions were PMF and the remaining one was other benign lesion (sensitivity 94%). 15 lesions showed iso or high-intensity on T2WI; 14 of them were lung cancer and the remaining one was an epithelioid cell granuloma (specificity 100%). Dynamic contrast-enhanced studies were performed in 19 lesions. 5 lesions showed no enhancement and 2 lesions showed ring-enhancement; 4 of 7 lesions were PMF (sensitivity 57%). 12 lesions showed diffuse enhancement; 8 of them were lung cancer, and the other 4 lesions were PMF (specificity 67%). CONCLUSION The most common MRI finding of PMF was hypo-intensity on T2WI. No enhancement or ring-enhancement on dynamic contrast-enhanced MRI did not necessarily suggest that the lesion was PMF. CLINICAL RELEVANCE/APPLICATION Signal intensity of the lesions on T2WI can be clue to the differentiation of PMF from lung cancer in patients with pneumoconiosis.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
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    ABSTRACT: Epiploic appendagitis is an ischemic infarction of an epiploic appendage caused by torsion or spontaneous thrombosis of the central draining vein. Epiploic appendagitis is self-limited without surgery, and it is imperative for clinicians to be familiar with this entity. A healthy 27-year-old man was admitted due to acute right lower quadrant abdominal pain. Physical examination showed focal abdominal tenderness with slight rebound tenderness. Laboratory tests showed leukocytosis and an increased serum C-reactive protein level. Computed tomography (CT) showed a fatty ovoid pericolonic mass measuring 12 mm in diameter, with a circumferential hyperdense ring that abutted on the ascending colon and was surrounded by ill-defined fat stranding with a hyperdense ring. These findings were diagnostic of primary epiploic appendagitis. The patient was given high-dose antibiotics due to the secondary inflammation involving the parietal peritoneum. Epiploic appendagitis presents with an abrupt onset of focal abdominal pain and tenderness without significant guarding or rigidity; it is an uncommon and difficult diagnosis. With awareness of this condition, however, evaluation by CT can provide an accurate diagnosis of epiploic appendagitis, distinguishing it from conditions with clinically overlapping manifestations.
    Medical science monitor: international medical journal of experimental and clinical research 10/2011; 17(10):CS113-5. · 1.22 Impact Factor
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    ABSTRACT: Distant metastasis of benign pleomorphic adenoma of salivary glands rarely occurs, and these neoplasms have been termed metastasizing pleomorphic adenoma. We present a rare case of metastasizing pleomorphic adenoma of the submandibular gland with lung and bone metastases obtained MR images and pathological findings. On MRI, the lesions were depicted as an area of high signal intensity on T2-weighted images (WI), reflecting myxoid or/and chondroid matrices. Metastasizing pleomorphic adenoma should be considered as a differential diagnosis when a pulmonary lesion shows high signal intensity on T2-WI and the patient has a medical history of salivary pleomorphic adenoma
    01/2009;
  • Tetsuji Yamaguchi, Shoichiro Takao, Masataka Uetani
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    ABSTRACT: PURPOSE The purpose of this study was to assess MR imaging features of radiographically occult fractures in osteonecrosis of the femoral head and to clarify the prognosis related with these fractures. METHOD AND MATERIALS Forty-two subjects with osteonecrosis of the femoral head (ONFH) with no radiographic collapse or subchondral lucency were recruited between April 2000 and September 2006. We divided the subjects into two groups, fracture and control groups. The fracture group consisted of 20 femoral heads (18 patients) with ONFH, in which radiographically occult fractures were detected on MR imaging. The control group consisted of 22 femoral heads (18 patients) with ONFH, in which no fracture was detected on MR imaging. We defined the fracture as a linear abnormal signal in the area of osteonecrosis. MR imaging findings were evaluated for the following findings in each group: extent of osteonecrosis, presence or absence of bone marrow edema (BME), and extent of BME. In the study group, signal intensity and location of fracture lines were also evaluated. All subjects were followed more than six months and were assessed for development of femoral head collapse. RESULTS No significant difference was found in the extent of osteonecrosis between two groups. BME was demonstrated in 20 cases (100%) of fracture group: extent of BME in femoral head in 7 cases (35%), in femoral head and neck in 6 cases (30%), and in femoral head to intertrochanteric region in 7 cases (35%). In control group, BME was demonstrated in only 2 cases (9%), which was localized in the femoral head. The signal intensity of the fracture on T2WI was low in 14 cases (70%) and mixed low/high in 6 cases (30%). The fractures were located in the weight-bearing portion in 19 cases (95%) and non-weight-bearing portion in one cases (5%). In the follow-up period, femoral head collapse developed in 19 cases (95%) of study group but no case (0%) in control group. CONCLUSION MR imaging is useful in detecting radiographically occult fractures associated with ONFH. The fractures are frequently accompanied by BME and can be a predisposing factor for the development of femoral head collapse. CLINICAL RELEVANCE/APPLICATION MR imaging is useful in evaluating fractures associated with ONFH.
    Radiological Society of North America 2006 Scientific Assembly and Annual Meeting; 11/2006
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    ABSTRACT: LEARNING OBJECTIVES To describe CT, MRI, and angiographic imaging features of aortic disease in systemic vasculitis. To learn clinical features of aortic disease in systemic vasculitis. To describe pathologic features of aortic disease in systemic vasculitis. ABSTRACT Main cause of common aortic diseases (ADs) such as aneurysm, dissection, or intramural hematoma of the aorta is atherosclerosis. However, these ADs can also be seen in a variety of systemic vasculitis (SV) such as Takayasu arteritis, Temporal arteritis, Kawasaki disease, Wegener granulomatosis, Behcet disease, inflammatory aortic aneurysm, and collagen disease. Imaging and clinical features of ADs occurring in SV may differ from those of usual ADs because of the presence of pre-existing inflammation in and around the aorta. Additionally, in some cases, prognosis of ADs in SV may be extremely poor because of the fragility of the aortic wall contributing to eventual rupture. Therefore, familiarity with characteristics of imaging and clinical features of ADs in SV is essential to make earlier and correct diagnosis enabling proper management. In this presentation, the clinical, imaging, and pathologic features of ADs in SV will be exhibited and discussed.
    Radiological Society of North America 2005 Scientific Assembly and Annual Meeting; 11/2005
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    ABSTRACT: Endovascular treatment is now an alternative to surgery for the treatment of iliac artery aneurysms (IAAs). A variety of minimally invasive therapeutic options are available (eg, coil embolization, stent-graft placement), and choosing an appropriate option is essential for achieving excellent long-term results and reducing potential complications. Preprocedural imaging with multi-detector row computed tomography or magnetic resonance imaging is necessary for evaluating patient eligibility and planning the interventional procedure. An imaging classification system for IAAs that is based on anatomic features and endovascular treatment options has been developed and may help determine therapeutic strategies for affected patients. Early experience indicates that endovascular treatment is safe and effective in treating IAAs, and it is expected that various devices that will make endovascular treatment easier to perform will soon become commercially available. However, large, long-term follow-up studies will be needed to determine whether this approach is a practical alternative to open surgery.
    Radiographics 11/2005; 25 Suppl 1:S213-27. · 2.79 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the growth rate of type B double-barrel aortic dissection with computed tomography (CT) and the factors influencing its enlargement. Sixty-two patients were entered into this study, and regular follow-up CT studies (mean; 49.1 months) were performed. The affected aortas and iliac arteries were divided into 5 segments (aortic arch, descending thoracic, suprarenal abdominal, infrarenal abdominal aorta, and iliac artery). Fifty-two of 62 patients (83.9%) had 1 or more segments increased in size during follow-up period. In a total of 177 segments, the presence or absence of blood flow in the false lumen and aortic diameter were evaluated on CT during the follow-up period. The factors (gender, diabetes mellitus, atherosclerotic disease, smoking, entry site in arch, initial diameter, chronic obstructive pulmonary disease, blood pressure, and age) influencing increase in the diameter and growth rate were also evaluated. Of 177 segments, 132 segments (74.6%) increased in size during the follow-up period. The presence of blood flow in the false lumen was the only significant risk factor for increase in the diameter in the univariate and multivariate analysis. The group with blood flow in the false lumen had a significantly higher mean growth rate (3.3 mm/year) than the group without blood flow (-1.4 mm/year) (P<0.0001). The growth rate of aortic dissections in thoracic aorta and abdominal aorta were 4.1 and 1.2 mm/year, respectively. There was a significant difference in the growth rate between the 2 groups (P=0.0003). In type B aortic dissection, the affected aortas have shown a high incidence of enlargement during the follow-up period, and more careful follow-up study is needed for aortic dissections in the thoracic aorta. The presence of blood flow in the false lumen is the most important risk factor for aortic enlargement.
    Circulation 09/2004; 110(11 Suppl 1):II256-61. · 15.20 Impact Factor
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    ABSTRACT: The purpose of our study was to evaluate the diagnostic performance of an artificial neural network (ANN) in differentiating among certain diffuse lung diseases using high-resolution CT (HRCT) and the effect of ANN output on radiologists' diagnostic performance. We selected 130 clinical cases of diffuse lung disease. We used a single three-layer, feed-forward ANN with a back-propagation algorithm. The ANN was designed to differentiate among 11 diffuse lung diseases by using 10 clinical parameters and 23 HRCT features. Therefore, the ANN consisted of 33 input units and 11 output units. Subjective ratings for 23 HRCT features were provided independently by eight radiologists. All clinical cases were used for training and testing of the ANN by implementing a round-robin technique. In the observer test, a subset of 45 cases was selected from the database of 130 cases. HRCT images were viewed by eight radiologists first without and then with ANN output. The radiologists' performance was evaluated with receiver operating characteristic (ROC) analysis with a continuous rating scale. The average area under the ROC curve for ANN performance obtained with all clinical parameters and HRCT features was 0.956. The diagnostic performance of four chest radiologists and four general radiologists was increased from 0.986 to 0.992 (p = 0.071) and 0.958 and 0.971 (p < 0.001), respectively, when they used the ANN output based on their own feature ratings. The ANN can provide a useful output as a second opinion to improve general radiologists' diagnostic performance in the differential diagnosis of certain diffuse lung diseases using HRCT.
    American Journal of Roentgenology 09/2004; 183(2):297-305. · 2.90 Impact Factor
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    ABSTRACT: Ground-glass opacity of the lung is often demonstrated on high-resolution CT (HRCT) in various diffuse lung diseases. Ground-glass opacity generally results from minimal thickening of the alveolar interstitium or partial filling in the alveolar spaces. We classify diffuse infiltrative lung diseases into two clinical categories, namely, noninfectious and infectious lung disease. In noninfectious lung disease, although ground-glass opacity can be observed as an isolated finding, it is commonly observed to be combined with other findings such as centrilobular micronodules, interlobular septal thickening, and cystic air-spaces. These associated findings may be important for the differential diagnosis. Ground-glass opacity may also be seen as a consequence of increased capillary blood volume in redistribution of blood flow. This condition of hemodynamic origin is observed in chronic obstructive pulmonary disease, airway disease, and vascular lung disease. Although ground-glass opacity is a nonspecific finding, it can suggest a specific diagnosis in certain clinical circumstances or indicate a potentially treatable disease. Therefore, accurate recognition and differential diagnosis of ground-glass opacity are important
    01/1998;
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    ABSTRACT: Introduction Computed tomography (CT), particularly high-resolution CT (HRCT), defines detailed lung morphology, and is useful in evaluating diffuse lung disease1,2 It allows assessment of the anatomic changes as well as physiologic responses in patients with diffuse lung disease. We herein review the HRCT findings of diffuse lung disease according to classification based on their predominant appearances
    01/1996;
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    ABSTRACT: The value of short inversion time inversion recovery (STIR) imaging in differentiating patients with aplastic anemia (AA) from those with myelodysplastic syndrome (MDS) was investigated. Thirty-nine patients with pancytopenia were diagnosed hematologically as having AA or MDS. These patients and 95 volunteers without hematologic disorders were then examined with STIR imaging. Hyperintense posterior pelvis was present in 25 of the 29 patients with MDS, including 17 of the 19 patients with refractory anemia. In contrast, high intensity of the posterior pelvis was absent in 8 of the AA 10 patients. High intensity of the femoral elements was present in 6 of the 8 patients with severe MDS and 3 of the 19 patients with refractory anemia. High intensity in the femoral elements was absent in all 10 AA patients. STIR imaging was useful in differentiating patients with AA from those with MDS
    01/1996;
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    ABSTRACT: PURPOSE/AIM The purpose of this exhibit is: 1. To present normal anatomy of the paravertebral region. 2. To review the CT and MRI findings of various paravertebral lesions. 3. To understand the significance of background of patients to make a correct diagnosis . CONTENT ORGANIZATION 1. Normal anatomy 2. Pathologic conditions 2-1.Neoplasm Neurogenic tumor, Pleural tumor, Lung cancer, Malignant lymphoma 2-2.Infection Infected spondylitis, Tuberculosis 2-3.Congenital disorder Meningocele, Neurenteric cyst 2-4.Specific diseases Extramedullary hematopoiesis, IgG4-related mediastinitis 3. Conclusions SUMMARY The major teaching points of this exhibit are: 1. Understanding normal anatomy of the paravertebral region 2. Knowledge of typical CT and MRI findings of various paravertebral lesions. 3. Understanding the significance of patient’s background to make a correct diagnosis.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting;