Department of Diagnostic Radiology1, General Surgery2, Pediatrics3, and Anatomic Pathology4, Asan Medical Center, University of Ulsan college of Medicine
ABSTRACT
PURPOSE : Sonography is a conclusive method in the diagnosis of infantile hypertrophic pyloric stenosis(IHPS). However, previous reports incompletely described the sonographic layers. This study was performed todefine the layers seen on high resolution sonography. MATERIAL & METHODS : We performed high resolution sonographywith 10-5 MHz linear transducer in 8 patients with IHPS. The layers seen on sonography were correlated withhistopathologic findings by obtaining thin section of thickened gastric wall during surgery. RESULTS : All casesshowed typical sonographic findings that were previously described. The thickened pyloric wall consisted of 5sonographic layers : extremely echogenic mucosal interface, hypoechoic mucosa, hyperechoic submucosa, mixedechogenic circular muscle layer, and hypoechoic longitudinal muscle layer. On longitudinal scan of pylorus,circular muscle fiber directions were identified as alternating bands of hyper-and hypoechogenicity with theappearance of zebra skin. CONCLUSION : Clear delineation of the layers of gastric wall and the muscle fiberdirections of hypertrophied circular muscle in IHPS showed by high resolution sonography. Our results arecontradictory to the previous reports that defined the sonolucent double tracks as collapsed lumen and theechogenic lines as mucosa. We believe that the multiple hypoechogenic bands seen in longitudinal scan representthe folded mucosal layers and that the echogenic lines are from the mucosal interface.