1 筑波大学附属病院検査部Department of Laboratory Medicine, Tsukuba University Hospital
2 筑波大学医学医療系臨床検査医学Faculty of Medicine, University of Tsukuba
3 筑波大学医学医療系循環器内科Cardiovascular Division, Faculty of Medicine, University of Tsukuba
目的：頸部放射線治療後の症例を対象に頸動脈超音波検査所見の特徴を検討し，危険因子を合わせた対照と比較することである．
対象と方法: 2012年4月から2014年3月に当院で頸動脈超音波検査を実施した症例の中で，癌治療のために頸部放射線照射の既往のある15例（年齢71±7歳，男性12例）を対象とした．臨床背景として放射線治療後の年数，原疾患，高血圧，脂質代謝異常，糖尿病，喫煙，脳梗塞の有無を調査した．頸動脈超音波検査では最大内中膜厚（IMT），プラークの性状，狭窄の有無，プラークスコアを計測した．傾向スコアマッチング法を用いて交絡因子の影響を調整し対照群を決定し，頸部放射線照射既往のある症例と比較した．
結果と考察：頸部放射線治療後に脳梗塞を発症した症例は15例中6例（40%）で放射線治療後5年以上経過していた．頸部放射線治療後症例の頸動脈超音波検査においてのプラーク性状は潰瘍性病変，低輝度プラークなどの臨床的に脆弱性を危惧する注意すべきプラークおよび有意狭窄が高頻度に認められた．
また，頸動脈超音波検査において傾向スコアマッチング法で決定した対照群と比較し動脈硬化が生じにくい総頸動脈を含め頸動脈の広範囲にIMTの増大を認めた．
以上より，放射線治療が頸動脈エコー所見に関与していることを示していると考えた．
結論：頸部放射線治療後の頸動脈超音波所見の特徴は両側頸動脈の広範囲，特に総頸動脈の注意すべきプラークや狭窄を認めることであった．放射線治療による頸動脈血管障害の活動性が持続し経年的に血管壁の不安定性や狭窄が進行する場合があり，超音波検査による定期的な経過観察が必要である．
Purpose: We examined the characteristics of carotid ultrasound findings in patients receiving cervical radiotherapy and compared with control cases with combined risk factors.
Subjects and Methods: Fifteen patients (age, 71±7 years, 12 males) with history of cervical radiation among those evaluated by carotid artery ultrasonography from April 2012 to March 2014 at our hospital were included in the study. Background clinical data on duration after radiotherapy, original disease, hypertension, dyslipidemia, diabetes, smoking, and cerebral infarction were investigated. Maximum intima-media thickness (IMT), plaque properties, stenosis, and plaque score were determined by carotid ultrasonography. The propensity score-matching method was used to determine control cases and adjust the influence of confounding factors for comparison with patients who received cervical radiation.
Results and Discussion: Six (40%) of 15 patients developed cerebral infarction after cervical radiotherapy, and more than 5 years had passed since radiation therapy. Plaque properties by carotid ultrasonography in patients receiving cervical radiotherapy had noticeable clinically vulnerable plaques such as ulcerative, low-echoic, and cautionable plaques, and significant stenosis were found frequently. By carotid ultrasonography, the IMT increase was observed in several carotid artery sites including the common carotid artery, which is rarely affected by arteriosclerosis, compared with the control cases determined by the propensity score-matching method. These findings suggested that radiation therapy was associated with changes in carotid pulse echogenic properties.
Conclusion: Carotid ultrasound findings after cervical radiation therapy were examined to characterize the range of changes including plaque formation and stenosis in bilateral carotid arteries, especially the carotid arteries. Changes were observed in the carotid arteries due to radiotherapy, instability, and stenosis of the vessel wall may progress over time, and regular follow-up by ultrasonic examination is necessary in these patients.
Key words: cervical radiation therapy; cerebral infarction; carotid ultrasound
© 2019 一般社団法人日本超音波検査学会© 2019 Japanese Society of Sonographers
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This page was last modified on 2019-03-29T17:50:57.000+09:00
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