Experimentally induced small-bowel tumor in rabbits: US-guided percutaneous 18-gauge core biopsy

To evaluate the safety and diagnostic yield of percutaneous 18-gauge core biopsy for an experimentally induced small-bowel tumor in a rabbit model.

Small-bowel tumors were induced by injecting VX2 tumor into 20 rabbits. After 3 weeks, the small bowel was filled with 100 mL of 2% diluted contrast agent containing methylene blue by using a 5-F catheter. Fifty biopsy firings for small-bowel tumor were performed with ultrasonographic (US) guidance by using an 18-gauge automatic gun. Computed tomography (CT) was performed before and immediately after biopsy. Any procedure-related complications, including leakage of air or fluid, hematoma, and perforation as seen at CT and identified at laparotomy, which was performed 48 hours after biopsy, were evaluated. White blood cell (WBC), red blood cell, and platelet counts; hemoglobin and hematocrit levels; and erythrocyte sedimentation rate were also obtained before and 48 hours after biopsy. Comparison was performed with paired t test. The diagnostic yield was calculated, and the specimen was evaluated whether fragments of mucosa were included or not.

No contrast agent leakage or pneumoperitoneum suggesting perforation was identified at CT or laparotomy. Fluid leakage was observed with manual squeezing at two biopsy sites (4%). In two rabbits, hemoperitoneum was observed at CT or laparotomy. Hematoma larger than 3 cm was observed in six rabbits. WBC count and erythrocyte sedimentation rate slightly increased, and red blood cells, hemoglobin, hematocrit, and platelets counts had decreased slightly after biopsy but were not significant (P >.05). Definitive histologic diagnosis of tumor was obtained in 44 (88%) of 50 biopsy sites. Fragments of mucosa were observed in 13 (28%) specimens of 10 rabbits.

Core biopsies of small-bowel tumor can be performed safely with an 18-gauge gun without severe complications and allow histologic diagnosis of small-bowel tumor with a good diagnostic yield.