To assess the value of contrast-enhanced ultrasound (CEUS) in guiding the biopsy of abdominal gastrointestinal stromal tumors (GISTs).

A total of 29 patients with gastrointestinal stromal tumors and receiving US-guided percutaneous biopsy were collected from June 2015 to February 2020 at the Department of Ultrasound Medicine of Chongqing University Cancer Hospital, among whom 11 patients underwent conventional ultrasound-guided biopsy and 18 underwent CEUS-guided percutaneous biopsy. The CEUS feature of masses were observed and recorded, including enhancement pattern, intensity, arrival time, time to peak, and internal perfusion characteristics. The high perfusion area was determined to be the biopsy target, and the safe pathway of puncture was selected. Each mass underwent 2 to 3 punctures, and if the obtained tissues achieved the requirements of pathological diagnosis, the needle biopsy was judged to be successful. The successful biopsy rate, positive sampling rate, pathological diagnosis coincidence rate, and complications were compared between the two groups.

In 29 patients, the maximum diameter of GIST tumors ranged from 7.3 to 30.2 cm, with an average of (14.8±6.2) cm. Of cases guided by CEUS, all showed strong heterogeneous enhancement, 17 had no contrast agent perfusion in internal areas, 11 had bulky and pedantic vascular perfusion, and 4 had centripetal perfusion. The arrival time was (14.1 ± 4.2) s, time to peak was (23.8 ±5.8) s, and wash-out time was (32.3± 8.8) s. There were 26 tissue strips obtained by conventional ultrasound-guided biopsy from 11 cases, and 36 tissue strips obtained by CEUS-guided biopsy from 18 cases. The successful biopsy rates were 69.2% and 94.4%, the sampling positive rates were 69.2% and 94.4%, and the diagnosis coincidence rates were 72.7% and 100%, respectively. The successful biopsy rate, positive sampling rate, and pathological diagnosis coincidence rate in the CEUS-guided group were significantly higher than those of the conventional ultrasound-guided group (P=0.008, 0.008, 0.045). No severe complications occurred in either group.

Large GISTs have certain CEUS characteristics. CEUS is a better way of guiding percutaneous biopsy than conventional ultrasound, and has appreciated clinical value for the preoperative qualitative diagnosis and guiding the treatment of GIST.