The Application of Dual-Pathway Contrast-Enhanced Ultrasound (CEUS) in the Treatment of Periappendiceal Abscesses

Abstract

Objectives: To explore the value of an ultrasound contrast agent (Sonovue) as an interventional treatment for periappendiceal abscesses.

Methods: From January 2019 to December 2020, 30 patients were recruited who were admitted to Jinan Central Hospital due to periappendiceal abscesses. Before the operation, 2.5 ml of SonoVue^® contrast agent was injected intravenously to determine the non-enhanced area of liquefaction and necrosis in the abscess cavity. The puncture sites were selected. Percutaneous catheterization and drainage (PCD) were performed under contrast-enhanced ultrasound guidance. After the operation, 1 ml of diluted SonoVue^® suspension was injected through the drainage tube to observe the position of the drainage tube, the degree of drainage and the development of the abscess.

Results: An ultrasound contrast agent was used preoperatively to assess the extent of the abscess. Liquefaction and necrosis were observed in the abscess cavity. CEUS showed hyperenhancement in the wall of the abscess in the arterial phase and the liquefied necrotic area in the abscess cavity was not enhanced before PCD. CEUS allowed operators to confidently identify the puncture site. Amongst the 30 cases of PCD, 27 cases showed the clear positioning of the drainage tube. The head of the drainage tube was placed in the ideal position and development could be seen in the abscess cavity. The diffusion effect of the contrast agent was good with no spillover and the drainage was unobstructed. Abscess development was observed in 3 patients after puncture injection of the contrast agent but the head of the drainage tube was not in the predetermined position. After adjusting the position of the drainage tube, CEUS was repeated and showed a strong diffusion effect of the contrast agent.

Conclusions: Intravenous injection of Sonovue before PCD of periappendiceal abscesses can evaluate the extent of the abscess, liquefaction and necrosis in the abscess cavity. The approach can also provide guidance for the placement of the drainage tube. After the operation, a diluted contrast agent was injected through the drainage tube. The position of the drainage tube and the flow direction of the contrast agent could be seen. This approach has good value for clinical applications to accurately judge the position of the drainage tube.

Keywords: Contrast-enhanced ultrasound; Periappendiceal abscess (PCD).

Fig. 1

Ultrasound imaging of a 57-year-old man undergoing dual-pathway contrast-enhanced ultrasonography and PCD. a Conventional two-dimensional ultrasound showing the location, characteristics and general condition of the periappendiceal abscess; b imaging before the operation, CEUS shows the scope of liquefaction and necrosis in the abscess cavity, evaluated the drainage effect and identified the best puncture point; c an 8F pigtail tube was selected for PCD, the arrow shows the position of the head end of the drainage tube; d image after the operation in which 1 ml of diluted Sonovue suspension was injected through the drainage tube to observe the position of the drainage tube, the degree of drainage and the development of the abscess

Fig. 2

CT images showing the post-operative results of PCD in a 57-year-old man. A CT scan was performed to determine the position of the drainage tube. The arrow shows the drainage tube located in the abscess cavity. Follow-up showed that 200 ml of fluid had drained from the patient demonstrating that the drainage tube was placed successfully

Fig. 3

Imaging of 76-year-old man who underwent conservative treatment after being diagnosed with appendicitis a year ago. The pain in the right lower abdomen had worsened for one month. a Conventional two-dimensional ultrasound showing a periappendiceal abscess with effusion; b CEUS showed no enhancement in the liquefied necrotic area of the abscess cavity and the effusion; c PCD in the abscess cavity, the arrow in c1 shows the position of the head end of the drainage tube; c2 shows the diluted contrast agent injected through the drainage tube to determine the catheter position; d PCD in the effusion that was aspirated and injected with antibiotics through the drainage tube as an anti-inflammatory flushing treatment

Fig. 4

CT imaging showing the positions of the two drainage tubes of the above 76-year-old man