Aim: To show how currently described techniques confuse interpretation of Doppler indices in lymph node characterization.
Materials and methods: The Doppler indices [resistivity index (RI) and pulsatility index (PI)] were obtained in 35 malignant lymph nodes by colour duplex sonography. Each node was sampled at eight different sites. Data were analysed using our own method, and methods employed in six previous studies.
Results: Restistivity index values varied between 0.69 and 0.88 and PI values ranged from 1.28 to 2.34. All but two methods produced different resistance indices (P < 0.05).
Conclusion: Conflicting results are obtained analysing the same data using different methods. Standardized techniques should be agreed and employed in future studies.
Copyright 2001 The Royal College of Radiologists.