Su Youn Sim MD, Presenter: Nothing to Disclose

Ji Seon Park MD,PhD, Abstract Co-Author: Nothing to Disclose

Kyung-Nam Ryu MD, Abstract Co-Author: Nothing to Disclose

Sequestered disc is not always apart and moved from parent disc, so its close contact with parent disc can be confused with disc protrusion or extrusion on MRI which requires different surgical approach. We evaluated the MR features of the sequestered disc focusing on separation from parent disc and other additional findings especially in the cases of definite separation is not seen on MRI.

From Jan 2003 to Jan 2004, 28 patients were surgically diagnosed as sequestered disc at our orthopedic surgery clinic(male:female=20:8, mean age=46 years, mean interval period between MR imaging and operation=19 days). Two radiologists retrospectively reviewed all MR imagings. First of all, we divided the patients with sequestered discs into two groups on the basis of whether definite separation from parent disc is seen or not on MR. In the latter group, the signal intensities of herniated discs compared with parent discs were evaluated on T1- and T2-weighted images. And we also assessed the presence of waist-like notch within the herniated disc.

Only 5 discs (5/28, 18%) showed obvious separation from parent disc. Among the remained 23 discs of indefinite separation, the notch was visible in 14/23 discs (61%) and not in 9/23 discs (39%). The signal intensities of the herniated discs on T1-weighted images were isointense with the parent discs in all cases. On the T2-weighted images, the signal intensities of herniated disc were higher than the parent discs in 9/23 discs (39%) and isointense in 14/23 discs (61%). 17/23 discs (74%) had either notch or high signal intensities on T2-weighted images.

Sequestered disc is commonly seen as a herniated disc without separation on MR imaging. It is necessary to consider the possibility of the sequestered disc when the herniated disc material shows notch within it or high signal intensity on T2-weighted image compared with the parent disc.

It is necessary to consider the possibility of the sequestered disc when the herniated disc material shows notch within it or high signal intensity on T2-weighted image compared with the parent disc.

Sim, S, Park, J, Ryu, K, MR Findings of Sequestered Disc: Is There Any Complementary Features Except Separation from Parent Disc?.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4439388.html