Improved ultrasound examination of pancreas grafts in type 1 (insulin-dependent) diabetic patients using tissue harmonic imaging

Abstract

Background: Combined kidney/pancreas transplantation is an established therapy for type 1 diabetic patients with end-stage renal disease. Ultrasound examinations are valuable noninvasive methods for postoperative monitoring of transplant recipients. Kidney grafts are easily to detect, whereas pancreas grafts are surrounded or covered by small bowel loops, which makes the examination much more difficult.

Patients and methods: Thirty-three simultaneous pancreas and kidney recipients (SPK) were examined by conventional sonography at 3.4 MHz and THI sonography (pulse inversion, 2.3 MHz) by an investigator experienced in abdominal ultrasound. The images were graded by two "blinded readers" using a scale (1-best image quality, 2-second best, 3-worst) with regard to tissue penetration and detail characterization of the pancreas grafts. The graders were unaware of the sonographic technique, respectively. Statistical evaluation was performed by the Mann-Whitney U test.

Results: In 25 cases (78%) pancreas grafts were detected by conventional sonography. The detection rate was higher using THI sonography, namely 29 cases (91%). Grading for tissue penetration revealed a mean value of 2.05 +/- 0.5 for conventional and 1.94 +/- 0.5 for THI sonography (P =.27). Detail characterization of the pancreas grafts was determined to show a mean value of 2.50 +/- 0.5 for conventional sonography and a significantly better mean value of 1.78 +/- 0.6 for THI sonography (P <.0001).

Conclusion: THI sonography improves the detection and the judgment of tissue characteristics of pancreas grafts. Penetration of ultrasound waves is not relevantly decreased by this new technique.