To investigate the ultrasonographic features of different types of inguinal hernia, and analyze the value of high-frequency ultrasound and color Doppler flow imaging (CDFI) in diagnosis of inguinal hernia.

The study retrospectively reviewed 65 patients with inguinal hernia treated in the Wanning people's hospital from January 2017 to August 2019. Of these, 55 were males and 10 were females; they were 5 to 78 years old, with an average age of (52.35±8.24) years old. All patients were subjected to high-frequency ultrasound and CDFI before surgery, and the examination results were compared with surgical pathological results.

Of 65 patients with inguinal hernia, 5 had direct hernia, 50 had reducible hernia, 3 had irreducible hernia, 5 had incarcerated hernia and 2 had strangulated hernia. Ultrasound images showed that there were no obvious changes in local abdominal wall of patients with direct hernia, few liquid dark areas were observed in the sac with clear layers, and CDFI showed few blood flow signals. In patients with reducible hernia and irreducible hernia, inguinal canal dilatation was observed, and intestinal tube and greater omentum echo were observed in the inguinal canal. The layer of intestinal wall was clear, without thickening, and there was greater omentum grid cystic-solid interphase chaotic echoes or uneven solid echoes. CDFI displayed multiple long and (or) short rod-shaped colored blood flow signals. For patients with incarcerated hernia, solid circular echogenic masses were observed in the groin, scrotum, and labia majora, with clear boundaries, thickened intestinal wall, and reduced echo. CDFI showed significantly decreased blood flow signals, and few scattered dotted blood flow signals were observed in the block masses. In patients with strangulated hernia, liquid dark areas in the hernia sac, obviously thickened intestinal wall, and extremely low echoes were observed. CDFI showed that blood flow signals sharply decreased or disappeared. Using surgical pathological results as the golden standard, the sensitivity, specificity, accuracy rate, misdiagnosis rate and missed diagnosis rate of ultrasound for inguinal hernia were 96.72% (59/61), 75.00% (3/4), 95.38% (62/65), 3.08% (2/65) and 1.54% (1/65), respectively. The coincidence rates for diagnosing direct hernia, reducible hernia, irreducible hernia, incarcerated hernia and strangulated hernia were 80.00% (4/5), 100% (50/50), 66.67% (2/3), 80.00% (4/5) and 100.00% (2/2). There was no significant difference in the inner diameter of the hernia ring measured by ultrasound and the value measured during operation (P>0.05).

Both high-frequency ultrasound and CDFI are of clinical significance in diagnosing ill-defined inguinal hernias, and they can be used as the first choice in clinical practice.