小縣 正明

Masaaki OGATA

神戸市立中央市民病院外科

Department of Surgery, Kobe City General Hospital

キーワード : Strangulation ileus, Hemorrhagic necrosis, Destruction of Kerckring's folds, Ultrasonography

The purpose of this study was to examine the ultrasonographic features of intestinal walls with hemorrhagic necrosis. For this, ultrasonograms (7.5 MHz) of resected intestinal tracts in five cases of strangulation ileus were taken in a water bath and were compared with their histological pictures. Ultrasonograms of strangulated intestinal walls (four specimens) with hemorrhagic necrosis were compared with those of edematous intestinal walls (six specimens) without hemorrhagic necrosis. Preoperative ultrasonograms were also reviewed.
In ultrasonograms taken in a water bath, the edematous intestinal walls showed a five- or seven- layer structure. The first layer was delineated as a highly echogenic line and the second layer was delineated as a hypoechoic zone. Kerckring's folds were intact and delineated clearly in each cases. In contrast, the intestinal walls with hemorrhagic necrosis showed the following characteristic changes in the ultrasonographic layer structure: (1) unclearness of the first layer (highly echogenic line), (2) enhancement of echogenicity in the second layer, (3) destruction or disappearance of Kerckring's folds, and (4) unclearness of the layer structure of the hypertrophic intestinal wall associated with enhanced echogenicity in all layers. Furthermore, these ultrasonographic changes appeared to reflect on their histopathological changes. In a clinical ultrasonic examination using a 3.5 MHz probe, destruction or disappearance of Kerckring's folds in an akinetic distended intestinal tract has been considered as one of the characteristic ultrasonographic signs of hemorrhagic necrosis of the strangulated intestinal tract. However, it shoud be pointed out that a 3.5 MHz probe is not suitable to delineate the layer structure of the intestinal wall. The results of the current study suggest that the changes in the ultrasonographic layer structure of the intestinal wall are considered as important signs in the diagnosis of strangulation ileus, so that a 7.5 MHz probe is recommended to be used.