Predictive Value of Coronary CT Angiography for Side-Branch Occlusion

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  • LETTERS TO THE EDITOR

    306 radiology.rsna.org n Radiology: Volume 274: Number 1January 2015

    benefit from coronary CT angiography, they were exposed to this radiation dose. In addition, these patients under-went two more ICA examinations within the same month. Moreover, during the same period, the patients received ap-proximately 6080 mL of contrast ma-terial during coronary CT angiography in addition to the contrast material ad-ministered during the two ICA exami-nations.

    In conclusion, although there is no accepted algorithm before revasculari-zation treatment in patients with total coronary occlusion, we think that per-forming coronary CT angiography in such a group of patients as described in this study is unnecessary. Radiation-based imaging techniques should be considered for patients likely to benefit from the procedure and not just for ex-perimental purposes.

    Disclosures of Conflicts of Interest: E.O. disclosed no relevant relationships. M.S. disclosed no relevant relationships. K.K. disclosed no relevant relationships.

    References 1. Zhang J, Li Y, Li M, Pan J, Lu Z. Collateral

    vessel opacification with CT in patients with coronary total occlusion and its relationship with downstream myocardial infarction. Ra-diology 2014;271(3):703710.

    2. Sun Z, Ng KH. Prospective versus retrospec-tive ECG-gated multislice CT coronary angi-ography: a systematic review of radiation dose and diagnostic accuracy. Eur J Radiol 2012;81(2):e94100.

    Response

    FromJiayin Zhang, MD, and Yuehua Li, MDDepartment of Radiology, Shanghai

    Jiao Tong University Affiliated Sixth Peoples Hospital, No. 600, Yishan Rd, Shanghai, China 200233 e-mail: drliyuehua@gmail.com

    We read the letter by Dr Ozturk and colleagues and appreciate their interest in our work. They raise several inter-esting questions, and we would like to respond to them.

    First, we completely agree with the opinion of Dr Ozturk and colleagues

    Predictive Value of Coronary CT Angiogra-phy for Side-Branch Occlusion

    FromXi-jie Gao, MDDepartment of Radiology, Second

    Peoples Hospital of Liaocheng, No. 306, Jiankang Rd, Linqing City, Shandong Province, China e-mail: xijiegao@163.com

    Editor:I read with interest the recent study in the June 2014 issue of Radiology by Dr Park and colleagues regarding to the predictive value of coronary computed tomographic (CT) angiography for side-branch occlusion (1). It indicates that the plaque thickness in the side-branch side of the proximal main vessel, plaque thickness in the noncarinal side of the side branch, side-branch lumen diam-eter, and side-branchdiameter steno-sis evaluated with CT angiography could be applied to predict side-branch oc-clusion after main-vessel stent implan-tation in bifurcation lesions. However, it may not be practical for clinicians to use the threshold of these indexes for planning the optimal strategy. As is shown in the article, the overall per-formance, which was expressed with the area under the receiver operating characteristic curve, is low or moderate (2). The sensitivity and specificity ac-cording to the threshold calculated by Dr Park and colleagues, however, were not present in the article. Based on the given receiver operating characteristic curve, we believe that no single thresh-old could yield a sensitivity and speci-ficity of more than 80% simultaneously. Therefore, we suggest that two thresh-olds should be defined, which could in-dicate a negative and positive predic-tive value greater than 80%, to provide more useful information for the refer-ring clinicians.

    Disclosures of Conflicts of Interest: disclosed no relevant relationships.

    References 1. Park JJ, Chun EJ, Cho YS, et al. Potential

    predictors of side-branch occlusion in bifur-

    that radiation-based imaging tech-niques must be considered in patients most likely to benefit from the proce-dures and not just for experimental purposes. In our study, patients under-went coronary CT angiography for comprehensive preprocedural evalua-tion of coronary CTO rather than for experimental purposes because coro-nary CT angiography has been vali-dated as one promising imaging mo-dality for treatment planning (1). The cardiologists who performed the sec-ond ICA examination, as Dr Ozturk and colleagues noted, were blinded to coronary CT angiography findings to enable better comparison between col-lateral vessel classification with coro-nary CT angiography and ICA. Because the second ICA was considered as the reference standard for collateral vessel assessment in this study, there would have been bias if cardiologists were in-formed of coronary CT angiography findings before the second ICA. How-ever, coronary CT angiography did serve as one of the imaging modalities for treatment planning when the sec-ond ICA was done and ICA-based col-lateral vessel classification had been established. The cardiologists who performed percutaneous coronary in-tervention were informed of coronary CT angiography findings afterward and took them into consideration along with findings of ICA and cardiac MR imaging so as to decide the individual treatment strategy. In other words, coronary CT angiography played a sig-nificant role in the decision-making process rather than being performed for a so-called experimental purpose. Finally, we are sorry for any confusion caused by the design description of this study.

    Disclosures of Conflicts of Interest: J.Z. disclosed no relevant relationships. Y.L. disclosed no relevant relationships.

    Reference 1. Rolf A, Werner GS, Schuhbck A, et al. Pre-

    procedural coronary CT angiography signifi-cantly improves success rates of PCI for chronic total occlusion. Int J Cardiovasc Im-aging 2013;29(8):18191827.

    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.

  • LETTERS TO THE EDITOR

    Radiology: Volume 274: Number 1January 2015 n radiology.rsna.org 307

    cation lesions after percutaneous coronary intervention: a coronary CT angiography study. Radiology 2014;271(3):711720.

    2. Swets JA. Measuring the accuracy of diagnos-tic systems. Science 1988;240(4857):12851293.

    Response

    Jin Joo Park, MD, and Young-Seok Cho, MD

    Cardiovascular Center, Seoul National University Bundang Hospital, 82 Gumiro-173-gil, Bundang, Seong-nam, Gyeonggi, 463-707, South Korea e-mail: flammeus1@gmail.com

    Dr Gao noticed that the practicality of the threshold of the new coronary CT angiography parameters may be limited owing to a low or moderate diagnos-tic performance. The best or optimal cutoff value of a test usually represents the mean or the median of a popula-tion. Several methods exist to deter-mine optimal cutoff values; however, all have grounds to be called optimal, or none are a true unique optimum. To our knowledge, our study was the first study of its kind to predict side-branch occlusion with coronary CT angiography parameters. By means of maximizing the sum of sensitivity and specificity, we provided a cutoff value of side-branchdiameter stenosis of more than 40% with an area under the re-ceiver operating characteristic curve, sensitivity, and specificity of 0.79 (95% confidence interval: 0.67, 0.92), 0.75, and 0.73, respectively, as presented in the article. When the new coronary CT angiography parameters are compared with the amino-terminal pro-brain na-triuretic peptide, or NT-proBNP, which is the best-known prognostic marker for heart failure and has an area un-der the receiver operating character-istic curve of 0.76 in the prediction of short-term outcomes (1), we believe that the coronary CT angiography pa-rameters are acceptable and clinically useful. However, the study results are

    Funding line should have been included as follows: This research was support-ed by the National Institutes of Health (grants 1R01EB01494401 and P30 CA08748).

    Frequency, Management, and Out-come of Extravasation of Nonionic Io-dinated Contrast Medium in 69 657 In-travenous Injections. Radiology 2007; 243(1):8087

    Page 87, middle column, reference 4 should have appeared as follows: Co-han RH, Bullard MA, Ellis JH, et al. Local reactions after injection of io-dinated contrast material: detection, management, and outcome. Acad Ra-diol 1997 Nov; 4(11):711718.

    Conventional US, US Elasticity Imag-ing, and Acoustic Radiation Force Im-pulse Imaging for Prediction of Malig-nancy in Thyroid Nodules. Radiology 2014;272(2):577586

    Page 583, the caption for Figure 3 should have included the following after the last sentence: (Reprinted, with permission, from Zhang YF, He Y, Xu HX, et al. Virtual touch tissue imaging on acoustic radiation force impulse elastography: a new technique for dif-ferential diagnosis between benign and malignant thyroid nodules. J Ul-trasound Med 2014;33[4]:585595.)

    Page 579, middle column, line 12 should read as follows: tion, 51 years 11; range, 1875 years; 93 of these pa-tients were also included in a previ-ously published report [J Ultrasound Med 2014;33{4}:585595])

    Editors Note: We stress to authors and research groups the importance to paying attention to manuscripts in the varied stages of acceptance written by any member of the group, to keep track of previously published patients and imaging studies, and to ensure that all figures are original unpublished material unless appropriately referenced with permission granted for reproduction.

    more hypothesis generating than de-finitive, and the optimal cutoff value should be optimally adjusted and val-idated in further clinical trials before it can be adopted in routine clinical prac-tice.

    Disclosures of Conflicts of Interest: J.J.P. disclosed no relevant relationships. Y.S.C. disclosed no relevant relationships.

    Reference 1. Januzzi JL, van Kimmenade R, Lainchbury J,

    et al. NT-proBNP testing for diagnosis and short-term prognosis in acute destabilized heart failure: an international pooled analysis of 1256 patients: the International Collabora-tive of NT-proBNP Study. Eur Heart J 2006;27(3):330337.

    ErrataNanoparticles for Imaging: Top or Flop? Radiology 2014;273(1):1028

    Page 10, bottom, left-hand column, In the affiliations footnote, after final version accepted November 6, the in-formation should have read as follows: F.K. and T.L. supported by Deutsche Forschungsgemeinschaft; F.K. sup-ported by NRW/EU-Ziel 2-Programm (Europischer Fonds fr Regionale Entwicklung 2007-2013: Entwicklung und Bildgebung patienten-optimiert-er Implantate), Exploratory Research Space Boost Fund at Rheinisch- Westflische Technische Hochschule Aachen University, and the Helmholtz Society Portfolio Program (Techno-logie and Medizin: Multimodale Bildgebung zur Aufklrung des In-vivo-Verhaltens von polymeren Biomaterialien); J.G. was supported by Louis V. Gerstner Young Investiga-tor Award and U.S. Department of Defense Program (PC1116670; opin-ions, interpretations, conclusions and recommendations are those of the au-thor and are not necessarily endorsed by the funding agency); and T.L. sup-ported by European Research Council (starting grant 309495: NeoNaNo). Page 11, bottom, right-hand column, a