reverse halo sign

Another cause of reverse halo sign: Wegener's granulomatosis

http://bjr.birjournals.org/cgi/content/long/80/958/849#R5

Reversed Halo Sign on High-Resolution CT of Cryptogenic Organizing Pneumonia: Diagnostic Implications

http://www.ajronline.org/cgi/content/figsonly/180/5/1251


in COP, WG