Terslev L, Diamantopoulos A P, Døhn U Møller, Schmidt W A, Torp-Pedersen S
Center for Rheumatology and Spinal Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Department of Rheumatology, Hospital of Southern Norway Trust, Kristiansand, Norway.
Arthritis Res Ther. 2017 Jul 20;19(1):167. doi: 10.1186/s13075-017-1374-1.
Ultrasound is used increasingly for diagnosing large vessel vasculitis (LVV). The application of Doppler in LVV is very different from in arthritic conditions. This paper aims to explain the most important Doppler parameters, including spectral Doppler, and how the settings differ from those used in arthritic conditions and provide recommendations for optimal adjustments. This is addressed through relevant Doppler physics, focusing, for example, on the Doppler shift equation and how angle correction ensures correctly displayed blood velocity. Recommendations for optimal settings are given, focusing especially on pulse repetition frequency (PRF), gain and Doppler frequency and how they impact on detection of flow. Doppler artefacts are inherent and may be affected by the adjustment of settings. The most important artefacts to be aware of, and to be able to eliminate or minimize, are random noise and blooming, aliasing and motion artefacts. Random noise and blooming artefacts can be eliminated by lowering the Doppler gain. Aliasing and motion artefacts occur when the PRF is set too low, and correct adjustment of the PRF is crucial. Some artefacts, like mirror and reverberation artefacts, cannot be eliminated and should therefore be recognised when they occur. The commonly encountered artefacts, their importance for image interpretation and how to adjust Doppler setting in order to eliminate or minimize them are explained thoroughly with imaging examples in this review.
超声越来越多地用于诊断大血管血管炎（LVV）。多普勒在LVV中的应用与在关节炎病症中的应用有很大不同。本文旨在解释最重要的多普勒参数，包括频谱多普勒，以及其设置与关节炎病症中的设置有何不同，并提供最佳调整建议。这将通过相关的多普勒物理学来阐述，例如聚焦于多普勒频移方程以及角度校正如何确保正确显示血流速度。给出了最佳设置的建议，特别关注脉冲重复频率（PRF）、增益和多普勒频率以及它们如何影响血流检测。多普勒伪像与生俱来，可能会受到设置调整的影响。需要了解并能够消除或最小化的最重要伪像有随机噪声、旁瓣伪像、混叠和运动伪像。降低多普勒增益可以消除随机噪声和旁瓣伪像。当PRF设置过低时会出现混叠和运动伪像，因此正确调整PRF至关重要。有些伪像，如镜面伪像和混响伪像，无法消除，因此在出现时应予以识别。本综述通过成像示例详细解释了常见伪像、它们对图像解读的重要性以及如何调整多普勒设置以消除或最小化它们。
