Abstract: Objective We mainly discuss the sonographic value of the diagnosis of acute appendicitis in the old people with atypical clinical symptoms. Methods There were 240 old patients with stomach-ache performed by ultrasound with the graded compression technique at the front abdomen wall, the appendix was visualized by the method from flank to ileocecum with the graded compression technique or scanned in the most painful spot that the patients felt, meanwhile the appendix imaging was improved both in the fundamental imaging and in the tissue harmonic imaging. We elucidated the different pattern imaging characteristic. Results The ultrasound findings included the following: 182 cases(75.8%) with no mass, either only with local bowel dilation or with local anechoic in the right abdominal periappendix, 20 cases(8.3%) with complex mass, 38 cases(15.8%) with atypical mass but with the characteristic of the anechoic tubular. All were validated by operation and pathology or treatment and follow-up. The ultrasound results were consistent with the pathological findings.The ultrsound patterns of acute appendicitis were charaterized by these appearances of the appendix on transverse scan or on sagittal scan:the thickened wall, the discontinuity, hyperechoic in the extraappendix, the local bowel dilation or the local anechoic in the extraappendix and the sonogram of acute appendicitis with complications such as perforation, the periappendiceal abscess or the omentum wrapping the appendix. Conclution Finally, abdominal ultrasound has proven to be useful in distinguishing the appendicitis from anechoic to the complex mass or the dilated appendix in the extraappendix area and the severity of the appendicitis especially in the old patients with the abdominal abnormality.

Key words: ultrasound, acute atypical appendicitis, pathology