Transit-time analysis of contrast agent in the liver: Advantages of contrast harmonic imaging compared with spectral Doppler quantification

The aim of the study was to examine if a pulse inversion technique, contrast harmonic imaging (CHI), could assess the arrival of Levovist in hepatic veins (transit-time), and to describe possible advantages over a previously described method with spectral Doppler quantification. Twelve patients were scanned using CHI after intravenous bolus-injection, the arrival was seen as white reflections in the hepatic veins. In patients with cirrhosis (n = 2) transit-time was 13 seconds, non-cirrhotic diffuse liver disease (n = 3) median 17 (range, 12-22), focal liver lesions (n = 7) median 24 (range, 16-27). Bolus-injection was repeated in five patients and transit-time assessed by spectral Doppler analysis: In four patients the two methods gave transit-times within 2 seconds apart, in one patient 5 seconds apart. In conclusion, it is possible to assess transit-time using CHI. The method is simpler than a previously described method which require computer analysis. Also, several hepatic veins can be assessed simultaneously.