荒木 一郎¹, 山本 脩治², 小林 健², 宮山 史朗², 楠 憲夫¹, 平岩 善雄¹, 吉田 誠¹, 品川 俊男¹, 魚津 幸蔵³, 木元 文彦³, 関川 博³, 永森 正秋⁴

Ichiro ARAKI¹, Syuji YAMAMOTO², Takeshi KOBAYASHI², Shiro MIYAYAMA², Norio KUSUNOKI¹, Yoshio HIRAIWA¹, Makoto YOSHIDA¹, Toshio SHINAGAWA¹, Kozo UOZU³, Fumihiko KIMOTO³, Hiroshi SEKIKAWA³, Masaaki NAGAMORI⁴

¹富山赤十字病院内科, ²富山赤十字病院放射線科, ³富山赤十字病院外科, ⁴山田温泉病院内科

¹Department of Internal Medicine, Toyama Red Cross Hospital, ²Department of Radiology, Toyama Red Cross Hospital, ³Department of Surgery, Toyama Red Cross Hospital, ⁴Department of Internal Medicine, Yamada Onsen Hospital

キーワード : Acute appendicitis, Ultrasonography, Five-layered structure, Diagnosis, High resolution transducer

Ultrasonic examinations were performed in 63 patients with suspected acute appendicitis. Using a 7.5 MHz linear transducer, inflamed appendices were visualized in 49 of 52 operated cases (94.2%) who had pathologically-confirmed appendicitis. This visualization rate is higher than rates previously reported. It has been said that the sonographic pattern of an inflamed appendix appears as an anechoic lesion with a rounded hyperechoic configuration. Using a 7.5 MHz transducer, we could clearly observe that the wall of the inflamed appendix was divided into five layers, as was the gastric wall. Ultrasonically, catarrhal-type appendicitis showed smooth muscular layer, while phlegmonous-type showed irregular muscular layer and gangrenous-type showed a disappearance of the five-layered structure. By carefully observing the five-layered structure, especially the muscular layer, we could distinguish catrarrhal-type appendicitis from phlegmonous- or gangrenous-type with an accuracy of 88.9%. Moreover, most pasients with an appendix of more than 8 mm in width had phlegmonous or gangrenous appendicitis. These results indicate that we should regard as a surgical indication any appendix with an irregular muscular layer or an apendix which is more than 8 mm in width. These findings may enable us to make more accurate diagnose of acute appendicitis. In conclusion, high resolution sonography using a 7.5 MHz transducer is usuful not only for diagnosing acute appendicitis, but also for evaluating its surgical indications.