Takaaki Ueda

Yamaguchi University, Yamaguti, Yamaguchi, Japan

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Publications (6)2.11 Total impact

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    ABSTRACT: PURPOSE To evaluate the safety and clinical effectiveness of covered Niti-S stent placement under multi-detector CT and fluoroscopy guidance for the palliation of dysphagia in patients with malignant esophageal obstruction. METHOD AND MATERIALS Under radiological imaging guidance using axial and sagittal CT scans, and fluoroscopy, covered Niti-S esophageal stents were placed in 31 consecutive patients with complete obstruction caused by malignant esophageal tumors (24 esophageal cancer, 7 lung cancer, 27 men and 4 woman; age range, 49-80 years; mean age, 70.2 years) between February 2010 and February 2012. The procedure time and technical success rate were evaluated. Swallowing improvement after stent placement was assessed by the following items: ability to eat and/or swallow (graded as follows: 3 = ability to eat normal diet, 2=ability to eat semisolids, 1=ability to swallow liquids, 0=complete obstruction). Procedural and post-procedural complications were also evaluated. In addition, survival (mean ± SD) was examined. RESULTS The mean procedure time was 38 ± 15 (SD) min (range, 22 – 65 min). Stent placement was technically successful in all patients; inadequate stent deployment did not occur in any cases. Ability to eat and/or swallow was improved and scored 2.4 (score 3, 15 cases, score 2, 14 cases, score 1, 2 case, score 0, no cases) after stent placement. No major and post-procedural complications were encountered. The mean survival time was 110±72 days (range 28-260 days). CONCLUSION The Niti-S stent appeared to be a safe and effective device for the palliation of dysphagia caused by malignant esophageal obstruction. Multi-detector CT and fluoroscopy image guidance helped the operators accurately place the stents in the esophagus. CLINICAL RELEVANCE/APPLICATION Image guidance using combined CT-and Fluoroscopy is useful for the accurate placement of the stents. The Niti-S Stent provides symptomatic relief of malignant esophageal obstruction.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: PURPOSE To examine the feasibility of deriving quantitative microcirculatory parameters and to investigate the relationship between vascular and metabolic characteristics of pancreatic tumors in vivo, using T1 weighted dynamic contrast enhanced (DCE) MRI. METHOD AND MATERIALS 16 patients who underwent surgery for a focal pancreatic mass, including pancreatic carcinoma (n=10), tumor forming pancreatitis (n=5), and islet cell tumor (n=1). DCE-MRI data were post-processed by using commercially available software (Avanto Tissue 4D Siemens Medical Systems). Transfer constant (Ktrans), extravascular extracellular blood volume (Ve), transfer constant from the extracellular extravascular space to plasma (Kep) and iAUC (initial area under the signal intensity-time curve) were calculated in the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery. Post operative pathological examination was used as the golden standard. RESULTS Microcirculatory parameters of tumors of 10 patients were lower than that of pancreatic parenchyma without islet cell tumor. The mean value of Extravascular extracellular blood volume (Ve) was 0.514±0.102 for tumor forming pancreatitis, 0.304±0.136 for pancreatic carcinoma and Ve in pancreatic carcinoma was significant lower than that of tumor forming pancreatitis and islet cell tumor (P=0.026) CONCLUSION Quantitative microcirculatory parameters analyzed by MRI was useful to predict the histopathology of pancreatic tumors. Quantitative microcirculatory parameters add to the diagnostic accuracy of pancreatic carcinoma from tumor forming pancreatitis. CLINICAL RELEVANCE/APPLICATION Quantitative microcirculatory parameters analyzed by MRI may be useful in defferentiating pancreatic carcinoma from other pancreatic disease.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: PURPOSE: We compared intermediate-weighted fast spin-echo (IW-FSE) images with intermediate-weighted fast-recovery FSE (IW-FRFSE) images in the diagnosis of meniscal tears. MATERIALS AND METHODS: First, 64 patients were recruited, and the arthroscopic findings (n = 40) and image analysis (n = 19) identified 59 torn menisci with 36 patients. Both the diagnostic performance and image quality in assessing meniscal tears was evaluated for IW-FSE and IW-FRFSE images using a four-point scale. Signal-to-noise ratio (SNR) calculation was performed for both sets of images. RESULTS: IW-FRFSE image specificity (100 %) for diagnosing the posterior horn of the medial meniscus (MM) tear with reader 1 was significantly higher than that of IW-FSE images (90 %). Mean ratings of the contrast between the lesion and normal signal intensity within the meniscus were significantly higher for the IW-FRFSE image ratings than the IW-FSE images in most meniscal tears. Mean SNRs were significantly higher for IW-FSE images than for IW-FRFSE images (P < 0.05). CONCLUSIONS: IW-FRFSE imaging can be used as an alternative to the IW-FSE imaging to evaluate meniscal tears.
    Japanese journal of radiology 07/2012; 30(9). DOI:10.1007/s11604-012-0108-1 · 0.74 Impact Factor
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    ABSTRACT: To determine whether it is possible to use bone single-photon emission tomography (SPECT) as a substitute for magnetic resonance (MR) imaging for differentiating malignant from benign vertebral compression fractures (VCFs). Ninety-seven fractures in patients who underwent both bone SPECT and MR imaging were included in our study. These 97 fractures were divided into two groups: malignant and benign VCFs. Two radiologists separately classified VCFs into malignant and benign according to the criteria for classifying VCFs on the planar, SPECT, and MR imaging as malignant or benign, as reported by many investigators earlier. In addition, 97 fractures were divided into two groups based on the MR images: VCFs with complete and partial replacement of the normal fatty marrow. The sensitivity, specificity, and accuracy of both the observers were calculated. The accuracy of the MR images was significantly greater than that of the SPECT images for both the observers (observer 1, P<0.001; observer 2, P<0.05). However, there were no significant differences in sensitivity, specificity, and accuracy for differentiating malignant from benign VCFs with complete replacement of the normal fatty marrow for both the observers [(observer 1: sensitivity, P=0.85; specificity, P=0.58; accuracy, P=0.63), and (observer 2: sensitivity, P=0.85; specificity, P=0.58; accuracy, P=0.87)]. Bone SPECT may be comparable with MR imaging for differentiating malignant from benign VCFs, especially, in the case of VCFs with a complete replacement of the normal fatty marrow.
    Nuclear Medicine Communications 03/2011; 32(3):192-8. DOI:10.1097/MNM.0b013e3283425665 · 1.37 Impact Factor
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    ABSTRACT: PURPOSE/AIM The purpose of this exhibit is to illustrate dynamic CT and MR imaging findings of various hypervascular hepatic tumors in order to help improve the radiologist’ diagnostic accuracy of these entities, and to highlight key differential diagnostic points of hypervascular nodules with histopathologic correlation. CONTENT ORGANIZATION 1)Review of dynamic CT and MR of hepatic hypervascular tumors (hepatocellular carcinoma, focal nodular hyperplasia, hepatocellular adenoma, cavernous hemangioma, sclerosing hemangioma, cholangiolocelluar carcinoma, MALT lymphoma, metastatic tumor caused by renal cell carcinoma, carcinoid tumor, acinar cell carcinoma, and melanoma, hepatic actinomycosis). 2) Highlight of key points for the correlation of radiologic and pathologic features. 3) Utility of contrast enhanced dynamic CT and MR imaging in the differential diagnosis. SUMMARY Differential diagnoses of hapervascular hepatic tumors include the wide spectrum from benign tumors to malignancies. Each lesion has typical CT/MR features in morphology, location, signal intensity and enhancement pattern that are useful for diagnosis. This exhibit will provide a diagnostic algorithm to aid reasonable differential diagnosis with emphasis on contrast enhanced dynamic CT, MR imaging, and pathologic features.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting;
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    ABSTRACT: PURPOSE/AIM The purpose of this exhibit is: 1. To familiarize the radiologist with recently developed 3D MR myelography 2. To review the basic principles of 3D MR myelography techniques 3. To learn characteristics of the technique and interpretation CONTENT ORGANIZATION 1. 3D MR myelography techniques - 3D STIR (short inversion time inversion recovery) - SPACE (sampling perfection with application optimized contrasts using different flip angle evolutions) - DESS (double-echo steady-state) - MEDIC (multi echo data imaging combination) - Diffusion-weighted imaging 2. 3T versus 1.5T 3. Clinical examples of each technique: cervical and lumbar spine SUMMARY The major teaching points of this exhibit are: 1. 3 Tesla has advantages over 1.5 Tesla when performing MR myelography despite technical challenges. 2. Understanding the principle of MR myelography techniques is critical for high quality spinal imaging.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting;