‘Chinese dragon sign’ describes the appearance of tortuous calcified splenic artery on an abdominal radiograph [1, 2]. The Dragon is a mythical creature and denoted generally as snake-like with four legs and considered one of the 12 animals in the Chinese zodiac [3] (Fig. 1). The tortuous course with arterial wall calcification resembles the body of dragon, and the more tortuous coiled segment near the splenic hilum resembles the head of dragon (Fig. 2).

Fig. 1
figure 1

Source: https://en.wikipedia.org/wiki/Dragon_(zodiac) #/media/File:Dragon.svg. Accessed 4 April 2018. This file is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported license

Image of The Chinese dragon

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Fig. 2
figure 2

a Radiograph of the upper abdomen showing the tortuous and calcified splenic artery in the left upper quadrant (arrows). b Coronal view of contrast-enhanced CT showing the tortuous and calcified splenic artery reaching the splenic hilum (arrows)

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Splenic artery tortuosity and calcification are common findings in the abdominal radiograph and computed tomography (CT) of the abdomen of elderly and diabetic population. Splenic artery shows a relatively linear course in the pediatric population and tortuosity develops with increasing age due to mismatch in the growth of vessel and distance between its origin and splenic hilum [4]. Calcification is usually medial (located in tunica media) with circumferential and continuous tram track appearance on radiographs. It is often an incidental finding but can be associated with aneurysms [5]. Splenic artery aneurysm is the commonest visceral artery aneurysm and has a small risk of rupture [6]. It can be calcified although splenic artery calcification has no relationship with the development or rupture of aneurysms. Splenic artery aneurysms cannot be confidently diagnosed on a radiograph and needs contrast-enhanced CT [7].