石村 美由紀¹, 林 理絵¹, 下司 洋臣¹, 小川 加奈子², 井内 和幸²

Miyuki ISHIMURA¹, Rie HAYASHI¹, Hiroomi SHIMOTSUKA¹, Kanako OGAWA², Kazuyuki IUCHI²

¹済生会富山病院臨床検査科, ²済生会富山病院内科

¹Department of Clinical Laboratory, Saiseikai Toyama Hospital, ²Department of Medicine Saiseikai Toyama Hospital

キーワード : color Doppler, dissection, superior mesenteric artery, ultrasound

症例は，64歳の女性．高血圧症で加療中，2005年10月14日突然，腹痛が出現し，内服薬を投与されるが症状が持続するため，一週間後，当院を受診した．腹部造影CTにて，上腸間膜動脈起始部から7‐8cmに渡り偽腔の血栓化と真腔の高度狭窄を伴う上腸間膜動脈解離を認め，小腸の虚血も疑われた．超音波検査でも，腹部造影CTと同様の所見であった．血流が保たれていることと症状が軽快しており，絶食など保存的治療にて様子をみた．第8病日での超音波検査では当初認めなかった上腸間膜動脈からの分枝血管を認め，第13病日では描出される分枝血管数はさらに増加した．自覚症状の消失や腹部造影CTでの小腸の虚血性変化も改善し，超音波検査での変化に一致する所見と考えられた．約3週間後には腹部造影CT上，偽腔の縮小と真腔の拡大を認め，約4ヵ月後の超音波検査では偽腔は確認されなかった．本例は腹部造影CT検査で経過を見る方法もあるが，被爆の問題と上腸間膜動脈本幹や分枝の血流を動的に把握出来る点で超音波検査が有用であった1例と考えられた．

The patient was a 64-year-old woman under treatment for hypertension who suddenly experienced abdominal pain on October 14, 2005. Oral medication was administered, but her pain persisted, and after 1 week, she presented herself at our hospital. Contrast-enhanced abdominal CT showed an isolated dissection of the superior mesenteric artery (SMA) 7 to 8 cm from its origin and having a true but severely narrowed lumen and a thrombotic false lumen. Ischemia of the small intestine was considered. The ultrasonographic findings coincided with those of the contrast-enhanced abdominal CT scan. Because the patient was in a generally good state of health and her blood flow was maintained, she was managed with such conservative treatment as fasting. On the 8th day of hospitalization, small vessels, branching from the trunk of the superior mesenteric artery, which were not originally depicted in ultrasound images, had emerged. On the 13th day, the number of these side branches was found to have increased. These ultrasonographic changes were consistent with improvement in the symptoms and ischemic images noted in the small intestine demonstrated by contrast-enhanced abdominal CT. The false lumen was no longer observable 4 months later. Both ultrasonography and contrast-enhanced abdominal CT were useful in diagnosing and observing the clinical course of this case of dissection of the superior mesenteric artery. Of the two modalities, ultrasonography offered special advantages, including dynamic visualization of vascular flow from various angles and sparing the patient exposure to radiation.