Ann Nucl Med (2015) 29:754–755 DOI 10.1007/s12149-015-1001-7

LETTER TO THE EDITOR

Accurate measurement of the normality values of macroaggregated albumin lung perfusion scan in hepatopulmonary syndrome He Zhao1,2 • Jiaywei Tsauo1,3 • Xiaoze Wang1,3 • Xiao Li1

Received: 1 May 2015 / Accepted: 25 May 2015 / Published online: 17 July 2015 Ó The Japanese Society of Nuclear Medicine 2015

Sir, We read with great interest the article by de Queiro´s et al. regarding the measurement of the normality and reproducibility parameters of lung perfusion scintigraphy using technetium-99m-labelled macroaggregated albumin (MAA) in the diagnosis of intrapulmonary vascular dilatations (IPVD) and the diagnosis of hepatopulmonary syndrome (HPS) [1]. However, we have some concerns about the validity of the conclusions due to several study design flaws. Firstly, as the connection between HPS (IPVD) and hepatosplenic schistosomiasis had not been assessed before, it is unsuitable to take the patients with hepatosplenic schistosomiasis as the study group. To acquire the normality values for detecting IPVD by MAA, the

This comment refers to the article available at doi:10.1007/s12149014-0915-9. & Xiao Li [email protected] He Zhao [email protected] Jiaywei Tsauo [email protected] Xiaoze Wang [email protected] 1

Institute of Interventional Radiology, West China Hospital, Sichuan University, No. 37, Guoxue Lane, Chengdu 610041, Sichuan, China

2

Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

3

Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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patients should be assigned to HPS (non-HPS) or IPVD (non-IPVD) groups. In addition, it seems that contrast-enhanced echocardiography, which is the first-line method for detecting IPVD, had not been performed to distinguish patients with IPVD from the normal subjects. Secondly, previous studies suggested that images should be obtained as soon as possible after radiotracer injection, to avoid overestimating the total shunt fraction resulting from MAA particles breaking down and escaping the lung field [2, 3]. However, the image acquisition of the current study was conducted with a 20-min interval, which was in accordance with the scan procedures of another study which also showed an overrated sensitivity (96 %) [4]. Although Brazilian population may affect the normal range of MAA scan, the delay of image acquisition may contribute more to the high shunt fraction. In summary, we consider that the high shunt fractions in this article may result from the inappropriate grouping and delay of the scan, rather than Brazilian population. And it should be cautious to draw the conclusions in the study. Acknowledgments This paper was made possible by the National Natural Science Fund of China (Grant Nos. 81371656 and 81171444). Compliance with ethical standards Conflict of interest of interests.

The authors have no real or perceived conflict

References 1. de Queiros AS, Brandao SC, Macedo LG, Ourem MS, Mota VG, Leite LA, et al. Evaluation of normality and reproducibility parameters of scintigraphy with (99m)Tc-MAA in the diagnosis of intrapulmonary vascular dilatations. Ann Nucl Med. 2015;29(1):46–51.

Ann Nucl Med (2015) 29:754–755 2. Wolfe JD, Tashkin DP, Holly FE, Brachman MB, Genovesi MG. Hypoxemia of cirrhosis: detection of abnormal small pulmonary vascular channels by a quantitative radionuclide method. Am J Med. 1977;63(5):746–54. 3. Abrams GA, Jaffe CC, Hoffer PB, Binder HJ, Fallon MB. Diagnostic utility of contrast echocardiography and lung perfusion scan in patients with hepatopulmonary syndrome. Gastroenterology. 1995;109(4):1283–8.

755 4. Krowka MJ, Wiseman GA, Burnett OL, Spivey JR, Therneau T, Porayko MK, et al. Hepatopulmonary syndrome: a prospective study of relationships between severity of liver disease, PaO(2) response to 100 % oxygen, and brain uptake after (99m)Tc MAA lung scanning. Chest. 2000;118(3):615–24.

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Accurate measurement of the normality values of macroaggregated albumin lung perfusion scan in hepatopulmonary syndrome.

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