Evaluation of contrast-enhanced ultrasound of the pancreas combined with concurrent hormone stimulation

PURPOSE: To evaluate the potential of combined administration of the gastrointestinal hormones secretin (Secrelux) and c-terminal cholecystokinin (CCK-8 s) together with contrast-enhanced ultrasound (CE-US) to generate an extended contrast enhancement of healthy pancreatic tissue.

MATERIALS AND METHODS: 14 anaesthetised pigs weighing 30-35 kg were studied. After laparotomy, the pancreas was located and a B-mode examination followed by a CE-US examination of the gland was made using SonoVue 1.5 ml. After an injection of Secrelux 1 U/kg and CCK-8 s 100 pmol/kg, a second CE-US examination was conducted. The hormones and the contrast agent were administered through a catheter in the superior vena cava. The sonographic images were stored for later evaluation.

RESULTS: The study showed that CE-US increased the echogenicity of the pancreas by an average of 15.6 decibel (dB) (confidence intervals [CI]: 13.72, 17.42) p < 0.0001, an increase of 24%. The administration of Secrelux and CCK-8 s in combination with CE-US further increased the echogenicity of the pancreas by an average of 3% (CI: 0.36, 5.36) p = 0.028. A new sequence of hormones and CE-US 20 min after the previous injection did not induce further enhancement. The area under the curve (AUC) was significantly larger using both hormones and CE-US compared with CE-US alone by an average of 66 dBx sec (CI: 28,103) p = 0.002.

CONCLUSION: It is possible to generate an extended contrast enhancement of healthy pancreatic tissue using CE-US combined with the administration of the gastrointestinal hormones secretin (Secrelux) and c-terminal cholecystokinin (CCK-8 s). Our results may improve the ability to discriminate between healthy pancreatic tissue and areas with a changed blood flow due to either neoplasm or other pathological lesions.