鯉渕 晴美, 中村 みちる, 谷口 信行, 小野 倫子, 藤井 康友, 重田 浩一朗, 尾本 きよか, 安里 満信, 伊東 紘一

Harumi KOIBUCHI, Michiru NAKAMURA, Nobuyuki TANIGUCHI, Tomoko ONO, Yasutomo FUJII, Kouichiro SHIGETA, Kiyoka OMOTO, Mitunobu ASATO, Kouichi ITOH

自治医科大学臨床検査医学

Department of Clinical Laboratory Medicine Jichi Medical School

キーワード : thymus, children, ultrasonography

背景：胸腺は小児の前縦隔に存在する臓器であり, 年齢があがるにつれ退縮する. 小児では, 画像上前縦隔の真の腫瘤と正常胸腺の鑑別がしばしば困難である. 今回我々は正常胸腺が超音波検査で何歳まで観察可能か検討した. 対象・方法：0-15歳までの233人を検査した. アプローチの方法は「右傍胸骨」「左傍胸骨」「上胸骨」からとした. 結果：胸腺は「右傍胸骨」からは3歳以下では80％以上で観察可能であったが, 4歳を越えるとその割合は著明に減少した. 「左傍胸骨」「上胸骨」からは「右傍胸骨」と比較すると年長児まで観察可能であった. 結語：胸腺は年長児まで超音波で観察可能である.

Background: Most of the thymus gland situated mostly in the anterior mediastinum in children, although decreases in size in young adults, in whom a normal thymus is sometimes difficult to distinguish from an anterior mediastinal tumor. We attempted to determine an age group in children in which the thymus can be visualized by ultrasound. Patients and Methods: Two hundred thirty-seven children aged 0 to 15 years were studied. The right parasternal, left parasternal, and suprasternal views were scanned with ultrasound to identify the thymus. Results: The right parasternal view identified the normal thymus in 80 percent of children aged less than 3 years, but the rate of detection decreased after the third year. Although the suprasternal and left parasternal views visualized the thymus in every age group; however, the right parasternal view did not. Conclusion: This study indicates that the normal thymus can be observed by ultrasound in children of all ages.