The Doppler shift is a change in frequency that occurs when sound (or light) is emitted from, or bounced off of, a moving object. When a moving target reflects a sound the frequency of the reflected sound wave is altered. The frequency is shifted up by an approaching target and shifted down by a receding target. This is illustrated in Fig. 3.1. The amount the frequency is shifted is proportional to the velocity of the moving object. Because the Doppler shift was originally described for energy in the visible light spectrum, an upward Doppler shift is referred to as a blue shift, (a shift to a higher visible light frequency) and a downward Doppler shift is referred to as a red shift.
Ultrasound utilization of the Doppler shift falls into three main categories. Analysis of the Doppler frequency spectrum allows for calculation of velocity, and is used in vascular studies. Color-flow Doppler and power Doppler superimpose a color image representing motion onto a B-mode image to illustrate location of motion (blood flow).
KeywordsThyroid Nodule Doppler Imaging Parathyroid Adenoma Doppler Flow Malignant Lymph Node
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Cerbone G, Spiezia S, Colao A, Di Sarno et al (1999) Power Doppler improves the diagnostic accuracy of color Doppler ultrasonography in cold thyroid nodules: follow-up results. Hormone Research 52(1):19–24PubMedCrossRefGoogle Scholar
Papini E, Guglielmi R, Bianchini A, Crescenzi A et al (2002) Risk of malignancy in nonpalpable thyroid nodules: predictive value of ultrasound and color Doppler features. J Clin Endocrinol Metab 87(5):1941–1946PubMedCrossRefGoogle Scholar
Berni A, Tromba L, Falvo L, Marchesi M et al (2002) Malignant thyroid nodules: comparison between color Doppler diagnosis and histological examination of surgical samples. Chir Ital 54(5):643–647PubMedGoogle Scholar
Frates MC, Benson CB, Doubilet PM, Cibs ES, Marqusee E (2003) Can color Doppler sonography aid in the prediction of malignancy of thyroid nodules? J Ultrasound Med 22:127–131PubMedGoogle Scholar
Fukunari N, Nagahama M, Sugino K et al (2004) Clinical evaluation of color Doppler imaging for the differential diagnosis of thyroid follicular lesions. World J Surg 28(12):1261–1265PubMedCrossRefGoogle Scholar
De Nicola H, Szejnfeld J, Logullo AF et al (2005) Flow pattern and vascular resistance index as predictors of malignancy risk in thyroid follicular neoplasms. J Ultrasound Med 24:897–904.PubMedGoogle Scholar
Levine RA (2006) Value of Doppler ultrasonography in management of patients with follicular thyroid biopsies. Endocr Pract 12(3): 270–274PubMedGoogle Scholar
Macedo TA, Chammas MC, Jorge PT et al (2007) Differentiation between the two types of amiodarone-associated thyrotoxicosis using duplex and amplitude Doppler sonography. Acta Radiol 48(4):412–421PubMedCrossRefGoogle Scholar
Bogazzi F, Bartelena L, Brogioni S et al (1997) Color flow Doppler sonography rapidly differentiates type I and type II amiodarone-induced thyrotoxicosis. Thyroid 7(4):541–545PubMedCrossRefGoogle Scholar
Ralls PW, Mayekowa DS, Lee KP et al (1988) Color-flow Doppler sonography in Graves disease: “thyroid inferno”. AJR 150:781–784PubMedGoogle Scholar
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