Improved imaging of liver metastases with stimulated acoustic emission in the late phase of enhancement with the US contrast agent SH U 508A: early experience

Radiology. 1999 Feb;210(2):409-16. doi: 10.1148/radiology.210.2.r99fe47409.


Purpose: To see whether stimulated acoustic emission (SAE) in the liver parenchyma in the late phase of enhancement with SH U 508A increases the conspicuity of occult metastases at ultrasonography (US).

Materials and methods: Eighteen patients with known hypo- or hypervascular hepatic metastases underwent US after SH U 508A administration, after a delay of at least 5 minutes, to ensure decay of blood pool enhancement. In 16 patients with visible metastases, conspicuity was compared on registered SAE and gray-scale scans by two blinded readers and by using computerized analysis of relative gray-scale and color Doppler conspicuity scores inside and outside the lesion. In nine patients, areas suspected of being involved but without definite gray-scale masses were imaged in the same way. Paired sections were analyzed by two blinded readers looking for parenchymal color defects without corresponding gray-scale masses; nine control images from three healthy volunteers were also included.

Results: Intense, transient parenchymal SAE was seen in all subjects. All metastases appeared as areas of reduced or absent signal. The conspicuity score was 80% for SAE versus 9% for gray-scale US (P < .001, Wilcoxon signed rank test). SAE-specific defects were seen in all patients but in none of the volunteers. Metastases seen on SAE but undetectable on gray-scale images were proved in three patients.

Conclusion: SAE with SH U 508A improves the conspicuity of metastases. SAE-specific defects may reveal isoechoic or subtle metastases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biopsy
  • Contrast Media*
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Liver / diagnostic imaging
  • Liver / pathology
  • Liver Neoplasms / diagnostic imaging*
  • Liver Neoplasms / secondary*
  • Male
  • Middle Aged
  • Pilot Projects
  • Polysaccharides*
  • Time Factors
  • Ultrasonography


  • Contrast Media
  • Polysaccharides
  • SHU 508