Echo-enhanced ultrasound with pulse inversion imaging: A new imaging modality for the differentiation of cystic pancreatic tumours

Abstract

Aim: To describe and discuss echo-enhanced sonography in the differential diagnosis of cystic pancreatic lesions.

Methods: The pulse inversion technique (with intravenous injection of 2.4 mL SonoVue) or the power-Doppler mode under the conditions of the 2nd harmonic imaging (with intravenous injection of 4 g Levovist) was used for echo-enhanced sonography.

Results: Cystadenomas frequently showed many vessels along fibrotic strands. On the other hand, cystadenocarcinomas were poorly and chaotically vascularized. "Young pseudocysts" were frequently found to have a highly vascularised wall. However, the wall of the "old pseudocysts" was poorly vascularized. Data from prospective studies demonstrated that based on these imaging criteria the sensitivities and specificities of echo-enhanced sonography in the differentiation of cystic pancreatic masses were >90%.

Conclusion: Cystic pancreatic masses have a different vascularization pattern at echo-enhanced sonography. These characteristics are useful for their differential diagnosis, but histology is still the gold standard.

Figure 1

Cystadenoma at conventional and echo-enhanced ultrasound. A: A tumour at the pancreatic tail (5 cm in diameter) with small cystic areas (small arrows) and thin fibrotic strands; B: Highly vascularized tumour arteries (large arrows) along the fibrotic strands (maximum of contrastation 15 s after injection of the echo-enhancer).

Figure 2

Cystadenoma at conventional and echo-enhanced ultrasound A: A tumour (7 cm in diameter) at the pancreatic tail with large cystic (c) and solid areas (s); B: A poorly vascularized solid (s) tumour (maximum of contrastation 15 s after injection of the echo-enhancer).

Figure 3

Pseudocust at conventional and echo-enhanced ultrasound A: A lesion with an echo-free pattern and a sharply delineated wall. The Wirsungs Duct is dilated; B: A highly vascularized wall (maximum of contrastation 20 s after injection of the echo-enhancer).