Chinese dragon sign: splenic artery calcification

‘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).

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].