2005 Fiscal Year Final Research Report Summary
Development of a new technique to detect thromboemboli in the venous circulation using Doppler ultrasound apparatus to predict pulmonary embolism due to deep vein thrombosis
| Project/Area Number |
15591332
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General surgery
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
HIROKAWA Masayuki Tokyo Medical and Dental University Hospital, Instructor, 医学部附属病院, 助手 (00315011)
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| Co-Investigator(Kenkyū-buntansha) |
IWAI Takehisa Tokyo Medical and Dental University, Graduate School, Department of Vascular and Applied Surgery, Professor, 大学院医歯学総合研究科, 教授 (90111591)
INOUE Yoshinori Tokyo Medical and Dental University, Graduate School, Department of Vascular and Applied Surgery, Assistant professor, 大学院医歯学総合研究科, 講師 (70280964)
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| Project Period (FY) |
2003 – 2005
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| Keywords | pulmonary embolism / deep vein thrombosis / embolus / vein / HITS / diagnosis / Doppler examination |
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| Research Abstract |
Most cases of acute pulmonary embolism (PE) are caused by deep vein thrombosis (DVT) in the lower extremities. PE occur serious condition in patients with postoperative DVT. Currently, PE is diagnosed by lung ventilation and perfusion scintigraphy, angiography, or enhanced chest computed tomography scan, however, no diagnostic examination can predict PE. We have developed a new technique to detect thromboemboli in the venous circulation using Doppler ultrasound apparatus to predict PE. Castered male swine were injected various size of thrombi through the external iliac vein into the inferior vena cava (IVC). High intensity signal (HITS) was detected at the IVC using Doppler ultrasound machine (EME Pioneer, Nicolet Biomedical, Companion, Madison, WI, USA). Thrombus could be detected in the venous system by the Doppler ultrasound device with embolic detecting function. 22 out of 25 thrombi (10 × 5mm) wee detected as HITS. The thrombi (10 × 5mm) were confirmed at the pulmonary artery by histopathological examination. Appropriate confidence level was 60%. A positive correlation was recognized between passage time and velocity at flow rate of 30 cm/s or less. If thrombus flew at the maximum speed (30 cm/s) in the inferior vena cava, the length of those was 10.4 ± 2.8 mm for 3 mm and 10.8 ± 4.9 mm for 5 mm, both of which were close to 10 mm. Thrombi could be detected as high intensity transient signal in the venous system. The appropriate confidence level was 60% and the off-line analysis should be performed. The size of emboli can be estimated if it is more than 3 mm when the venous flow rate is 30 cm/s or less. Our results suggested that Doppler ultrasound monitoring technique can evaluate risk of PE in patients with deep vein thrombosis.
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