Aortic cobwebs: An anatomic marker identifying the false lumen in aortic dissection - Imaging and pathologic correlation

PURPOSE: To describe and estimate the frequency of fibroelastic cords or bands projecting from the false lumen wall ("aortic cobwebs") in acute and chronic dissections. MATERIALS AND METHODS: Pathologic specimens (n = 23), routine magnetic resonance (MR) images (n = 27), and intravascular (n = 5) and transesophageal (n = 3) ultrasound (US) images from 43 patients with aortic dissection were reviewed, and the presence and configuration of cobwebs were noted. RESULTS: Aortic cobwebs usually bridge the junction of the dissection flap with the outer wall of the false lumen (the line of dissection) but occasionally project like small tendrils from the false lumen wall remote from the line of dissection. Cobwebs were found in 17 of 23 pathologic specimens and on six of 27 MR images, two of five intravascular US scans, and one of three transesophageal US scans. CONCLUSION: Aortic cobwebs most likely represent residual ribbons of media that have been incompletely sheared from the aortic wall during the dissection process. As such, they can serve as an anatomic marker of the false lumen. They are occasionally seen on routine aortic images and may, therefore, prove useful for orientation during percutaneous or surgical interventional procedures to relieve ischemic complications of aortic dissection.