Cobweb sign in aortic dissection

Cobweb sign in aortic dissection

Cobweb sign in aortic dissection are slender linear areas of low attenuation seen occasionally in the false lumen in contrast enhanced computed tomographic scans. They are specific for the false lumen and help in the identification of false lumen [1]. The slender linear areas correspond to incompletely dissected aortic media. It is thought to be a specific sign for the false lumen, but with low sensitivity as it is not seen very frequently.

Williams et al studied aortic cobwebs by multiple modalities [2]. They studied 23 pathological specimens, 27 magnetic resonance studies, 5 intravascular ultrasound scans and 3 transesophageal ultrasound images from and 43 patients with aortic dissection. Cobwebs were found in 17 of the 23 pathological specimens, while it was found only in 6 of the 27 magnetic resonance images. They were noted in 2 of the 5 intravascular ultrasound images and 1 of the 3 transesophageal ultrasound scans.

References

1. Zhonghua Sun, Yan Cao. Multislice CT virtual intravascular endoscopy of aortic dissection: A pictorial essay. World J Radiol. 2010 Nov 28;2(11):440-8.
2. D M Williams, A Joshi, M D Dake, G M Deeb, D C Miller, G D Abrams. Aortic Cobwebs: An Anatomic Marker Identifying the False Lumen in Aortic Dissection–Imaging and Pathologic Correlation. Radiology. 1994 Jan;190(1):167-74.