1. Vascularity of liver tumours and recent advances in Doppler ultrasound
Stefano Gaiani, Laura Volpe, Fabio Piscaglia, Luigi Bolondi 
Journal of Hepatology 
Volume 34, Issue 3, Pages (March 2001)
DOI: /S (01)

2. Fig. 1
Power Doppler and Doppler spectral analysis of a small focal nodular hyperplasia of the 5th segment of the liver. Power Doppler imaging (on the left side) clearly shows the feeding artery which surrounds the nodule and the radial shape of the intranodular vasculature. Doppler spectral trace (on the right side) shows a high peak frequency (over 3 kHz) with spectral broadening and wide diastolic phase, corresponding to a low impedance trace (resistive index 0.50).
Journal of Hepatology  , DOI: ( /S (01) )

3. Fig. 2
Power Doppler and Doppler spectral analysis of a small (1 cm) non-malignant hepatocellular nodule in cirrhosis. Power Doppler imaging (on the left side) displays only few vascular signals at the periphery of the hyperechoic nodule, while Doppler spectral trace (on the right side) shows two different low-frequency vascular signals: a continuous venous signal and a pulsatile trace (with a peak frequency less than 0.5 kHz), resembling those of the normal intrahepatic portal and arterial flows.
Journal of Hepatology  , DOI: ( /S (01) )

4. Fig. 3
Colour Doppler and Doppler spectral analysis of a hepatocellular carcinoma of the left lobe of the liver. The tumour appears as a hyperechoic nodule of 5 cm in diameter, with only few intranodular vascular signals at colour Doppler imaging (on the left side). Doppler spectral trace (on the right side) shows a high peak frequency (4.4 kHz) with spectral broadening and low diastolic phase, corresponding to a high impedance trace (resistive index 0.90).
Journal of Hepatology  , DOI: ( /S (01) )

5. Fig. 4
Hepatocellular carcinoma of the right lobe of the liver. At conventional ultrasound imaging (above), the tumour (4 cm in size) is poorly detectable as it displays an echopattern similar to that of the surrounding liver parenchyma. Using contrast-enhanced harmonic technology (below), an intense transient enhancement is evident in the liver tissue during the parenchymal phase, while the tumour remains hypoechoic and is better defined.
Journal of Hepatology  , DOI: ( /S (01) )