The aim of this study was to ascertain whether a new ultrasound technique, namely pulse inversion imaging, could assess the arrival of a contrast agent in the hepatic veins, and to describe possible advantages of this procedure in determining transit time over a previously described method based upon spectral Doppler quantification. 15 subjects were scanned using pulse inversion imaging. A bolus injection of 2.5 g Levovist (Schering AG, Berlin, Germany) 300 mg x ml(-1) was given into an antecubital vein. Median transit times of 16 s (range 14-20 s) were found in patients with liver cirrhosis (n=4), 22 s (range 16-27 s) in patients with focal liver lesions (n=8) and 31 s (range 30-32 s) in control subjects (n=3). The maximum interobserver variation was 2 s and the maximum intraobserver variation was 3 s (n=10). Transit time was assessed by both pulse inversion imaging and spectral Doppler quantification in six patients. Comparison of the two methods showed transit times within 2 s apart in five patients and within 5 s apart in one patient. In conclusion, it is possible to assess transit time using pulse inversion imaging. This method is simpler than a previously described method requiring computer analysis. Moreover, several liver veins can be assessed simultaneously. Different transit times were observed in different liver veins in two patients with liver tumours. A short transit time (<27 s) appears to be found only in patients with liver disease. After transit time assessment, it is possible to use the injected contrast agent for late phase imaging of the liver parenchyma.

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Objective: To examine the effect of contrast agents on Doppler ultrasound findings in the synovial membrane in the wrist and fingers of healthy volunteers. Material and methods: Eleven healthy subjects were included in the study (5 women and 6 men, mean age 38 years, range (20-60)). They had no clinical signs of inflammatory or degenerative joint diseases. A total of 66 joints were examined-6 joints for each subject: wrist and metacarpophalangeal (MCP) joints 1-5-before contrast injection and after Levovist and SonoVue injection with a 30 minute interval. Results: Colour Doppler activity was detected in 10/55 (18%) MCP joints before contrast injection and in 29/ 55 (53%) and 28/55 (51%) joints after Levovist (p,0.0001) and SonoVue injection (p = 0.0001), respectively. A significant increase in Doppler activity in the radial (p,0.05) and ulnar (p = 0.01) parts of the wrist joint was detected only after SonoVue injections. With spectral Doppler no difference was found in the resistive index (RI) in the vessels measured before as compared with those only detected after contrast injection. Conclusion:The number of joints with colour Doppler activity in healthy volunteers was increased by the use of contrast agents. No changes in RI were detected. The value of contrast agents remains to be demonstrated in inflammatory diagnostics. Doppler ultrasound is used increasingly in the evaluation of joint inflammation and has the advantage of giving an objective analysis of the disease without ionising radiation. It is accessible in many outpatient clinics, has no contraindications, and poses no problems of patient compliance. Colour and power Doppler 1-6 have been used to identify the hyperaemia associated with inflammation 1-4 by visualising the vascularity in the inflamed synovial membrane. With spectral Doppler it is possible to evaluate the type of flow-that is, low resistance versus high resistance, in these vessels expressed by the resistive index (RI). Previous studies have shown that low RI values are associated with inflammation. [3][4][5][6] Ultrasound contrast agents in the form of microbubbles are used to enhance the scattering reflection from blood in order to increase the sensitivity of the Doppler examination. They have within the past few years been used to amplify the colour Doppler signal in patients with inflammatory joint conditions, and one study also used spectral Doppler for the examination of vessels. 3 The results have been divergent. Although some studies have reported Doppler signals from healthy joints without the use of contrast agents, 7 8 Doppler signals in healthy subjects were neither seen before nor after contrast injection in other studies.9-11 The use of contrast agents in rheumatology is still being investigated, and so far the studies have not agreed about the findings and there is no consensus about the recommendations for future use of contrast agents in inflamed joints. Previous studies have shown that it is possible to detect vascularisation in normal joints without the use of contra...