Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. 304 radiology.rsna.org n Radiology: Volume 259: Number 1—April 2011 LETTERS TO THE EDITOR index of the response to chemotherapy in lo- cally advanced breast cancer: a preliminary study. Eur Radiol 2010;20(2):303–308. 3. Woodhams R, Kakita S, Hata H, et al. Identi- fication of residual breast carcinoma following neoadjuvant chemotherapy: diffusion-weighted imaging—comparison with contrast-enhanced MR imaging and pathologic findings. Radiology 2010;254(2):357–366. 4. Nilsen L, Fangberget A, Geier O, Olsen DR, Seierstad T. Diffusion-weighted magnetic res- onance imaging for pretreatment prediction and monitoring of treatment response of pa- tients with locally advanced breast cancer undergoing neoadjuvant chemotherapy . Acta Oncol 2010;49(3):354–360. 5. Pickles MD, Gibbs P, Lowry M, Turnbull LW. Diffusion changes precede size reduction in neoadjuvant treatment of breast cancer . Magn Reson Imaging 2006;24(7):843–847. 6. Sharma U, Danishad KK, Seenu V, Jagannathan NR. Longitudinal study of the assessment by MRI and diffusion-weighted imaging of tumor response in patients with locally advanced breast cancer undergoing neoadjuvant chemo- therapy . NMR Biomed 2009;22(1):104–113. 7. Padhani AR, Liu G, Koh DM, et al. Diffusion- weighted magnetic resonance imaging as a cancer biomarker: consensus and recommen- dations. Neoplasia 2009;11(2):102–125. Why Do We Have So Many Controversies in Thyroid Nodule Doppler US? From Maria Cristina Chammas, MD, PhD Department of Radiology, Hospital das Clínicas da Faculadade de Medicina da Universidade de São Paulo, Av Manoel dos Reis Araujo 453, São Paulo, 04664-000, Brazil e-mail: mcchammas@hotmail.com Editor: I read with interest the article (1) by Dr Moon and colleagues that appeared in the April 2010 issue of Radiology. Al- though I respect the authors and their expertise, I am concerned that prob- lems in the methods used may have led to disappointing results. The classification system used in the report does not work well for predict- ing malignancy; this is particularly true when using high-end equipment. Just classifying lesions by presence of intra- nodular vascularization underestimates the capacity of color Doppler ultraso- nography (US) (2–5). High-resolution power (or color) Doppler US can be used to detect intra- nodular blood flow in around 80% of thyroid nodules. A more relevant obser- vation is the location of vascularity in the central or peripheral region (surely, a nodule could have equal vasculariza- tion in the central and peripheral re- gions, making yet another class) (3). Another area of concern is the power or color Doppler US equipment settings used. These must be set to low wall filter, a Doppler gain of about 80–90, and a velocity scale of around 3.0 or 4.0 cm/sec. Furthermore, for this ex- cellent equipment (iU22; Philips Med- ical Systems, Bothell, Wash), the best performance is reached when the pen- etration on color mode is selected (thy- roid preset modified). Another technical issue could also explain the surprising results. It is im- portant to use minimal probe pressure when evaluating superficial lesions with power Doppler US because even light compression with the probe can oblit- erate low-velocity flow (3). Many authors have reported good results using power Doppler US to pre- dict malignancy when using the new classification system (3–11) and when using cytologic or histologic findings as the reference standard (12,13). Disclosures of Potential Conflicts of Interest: M.C.C. No potential conflicts of interest to disclose. References 1. Moon HJ, Kwak JY, Kim MJ, Son EJ, Kim EK. Can vascularity at power Doppler US help predict thyroid malignancy? Radiology 2010; 255(1):260–269. 2. Lagalla R, Caruso G, Novara V, Cardinale AE. Flowmetric analysis of thyroid diseases: hy- pothesis on integration with qualitative color-Doppler study [in Italian]. Radiol Med (Torino) 1993;85(5):606–610. 3. Chammas MC, Gerhard R, de Oliveira IR, et al. Thyroid nodules: evaluation with power Doppler and duplex Doppler ultrasound. Otolaryngol Head Neck Surg 2005;132(6): 874–882. 4. Hamazaki N, Kounoike Y, Suzaki Y, et al. Usefulness of color Doppler sonography in the diagnosis of thyroid nodules: comparison of velocity mode with power mode. J Med Ultrasonics 1997;24(6):25–29. 5. Miyakawa M, Onoda N, Etoh M, et al. Diag- nosis of thyroid follicular carcinoma by the vascular pattern and velocimetric parame- ters using high resolution pulsed and power Doppler ultrasonography . Endocr J 2005; 52(2):207–212. 6. De Nicola H, Szejnfeld J, Logullo AF, Wolosker AM, Souza LR, Chiferi V Jr . Flow pattern and vascular resistive index as predictors of malignancy risk in thyroid follicular neoplasms. J Ultrasound Med 2005;24(7):897–904. 7. Foschini MP, Papotti M, Parmeggiani A, et al. Three-dimensional reconstruction of vessel distribution in benign and malignant lesions of thyroid. Virchows Arch 2004; 445(2):189–198. 8. Foschini MP , Ragazzi M, Parmeggiani AL, et al. Comparison between echo-color Dop- pler sonography features and angioarchitec- ture of thyroid nodules. Int J Surg Pathol 2007;15(2):135–142. 9. Fukunari N, Nagahama M, Sugino K, Mimura T, Ito K, Ito K. Clinical evaluation of color Doppler imaging for the differential diagnosis of thyroid follicular lesions. World J Surg 2004;28(12):1261–1265. 10. Giammanco M, Di Gesù G, Massenti MF, Di Trapani B, Vetri G. Role of color flow Doppler sonography in pre-operative diag- nostics of the thyroid pathology. Minerva Endocrinol 2002;27(1):1–10. 11. Iared W, Shigueoka DC, Cristofoli JC, et al. Use of color Doppler ultrasonography for the prediction of malignancy in follicular thyroid neoplasms: systematic review and meta-analysis . J Ultrasound Med 2010;29(3):419–425. 12. Lebkowska UM, Dzieciol J, Lemancewicz D, Boguslowicz W, Lewszuk A. The influence of the vascularisation of the follicular thyroid nodules on the proliferative activity of the follicular cells. Folia Morphol (Warsz) 2004; 63(1):79–81. 13. Gritzmann N, Koischwitz D, Rettenbacher T. Sonography of the thyroid and parathyroid glands. Radiol Clin North Am 2000;38(5): 1131–1145, xii. Response From Hee Jung Moon, MD, and Eun-Kyung Kim, MD Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, 120-752 Seoul, Korea e-mail: ekkim@yuhs.ac