Pedicle Marrow Signal Hyperintensity on Short Tau Inversion Recovery- and T2-Weighted Images: Prevalence and Relationship to Clinical Symptoms

Type 1 pedicle marrow signal intensity changes associated with an early to progressive pars fracture and absence of signal intensity changes in a terminal spondylolysis in an 18-year-old man with back pain and bilateral spondylolysis. Right (A) and left (B) parasagittal MR images of the lumbar spine. In each figure, the T1, T2, STIR, and multiplanar reformatted oblique and parasagittal CT images are shown, from left to right. A, Hypointensity of the L4 right pedicle is evident on T1 with increased signal intensity on T2- and STIR-weighted images (arrows). A relatively acute fracture is noted through the pars interarticularis on the CT images (arrow). B, Signal intensity of the left pedicle is normal on all sequences. The CT images reveal an older pars fracture (arrows).

Type 1 pedicle marrow signal intensity changes associated with evolving pedicle fractures in a 13-year-old male adolescent. A, Left type 1 pedicle marrow signal intensity changes, which are best appreciated on the STIR sequence. From top to bottom, each row shows T1-, T2-, and STIR-weighted sequences. The MR study on February 9, 2005, demonstrates increased signal intensity within the left pedicle and proximal superior facet, which is best appreciated on the STIR sequence (arrow). He was treated conservatively and the back pain improved. The follow-up study on March 23, 2005, demonstrates some improvement in the hyperintensity of the left L5 pedicle. A follow-up MR study on August 4, 2005, demonstrates increased type 1 pedicle marrow changes of L5 bilaterally with a fracture line at the junction of the pedicle and superior articular facets (arrow). A follow-up study from February 20, 2006, shows some improvement of the increased signal intensity on STIR and T2 (arrows), and the previous fracture line is no longer appreciated. Similar changes were seen on the right. The patient's back pain was less severe but still present. B, Axial T2 MR images (top row) through the L5 pedicle on February 9, 2005, and August 4, 2005, and axial CT images (bottom row) through the L5 pedicle on February 18, 2005, and August 8, 2005. The CT obtained on February 18, 2005, was read as negative for fracture. The follow-up MR image demonstrates bilateral fracture lines through the L5 pedicles. The follow-up CT from August 8, 2005, shows clearly demarcated fractures through the junction of the pedicle and superior facet of L5 bilaterally (arrows).

Type 1 pedicle marrow signal intensity changes associated with new and old pedicle fractures in a 64-year-old woman. A, Right parasagittal T1-, T2-, and STIR-weighted images that demonstrate a discrete fracture line through the pedicles of L4 bilaterally without pedicle marrow signal intensity changes (long arrow) and a less obvious fracture line on T1 images through the L5 pedicle with concomitant type 1 pedicle marrow changes (short arrows). Signal intensity changes at L5 and clinical symptoms had resolved at 8 months of follow-up. B, Right and left parasagittal multiplanar reformatted CT images through the lumbar spine and axial images through the pedicles of L5. Note the lucent appearance of the subacute fracture site through the pedicles on the parasagittal multiplanar reformatted images and adjacent axial CTs and the less well-defined fracture and adjacent marrow signal intensity alteration through the pedicles on the axial MR images (arrows).The signal intensity change is more obvious on the axial MR image on the right. Note the sclerotic appearance of an older fracture site through the L4 pedicle on the CT images.

A 25-year-old man with back pain. The left parasagittal T1, T2, and STIR images (left to right) from August 3, 2006, and January 19, 2007, which demonstrate type 1 pedicle marrow changes on the August 3, 2006, study. The hyperintensity on T2 and STIR images has resolved by the second study. On the T1 images, the decreased marrow signal intensity (type I) noted initially (August 3, 2006) has converted to a type 2 marrow (increased signal intensity on T1) on the second study (January 19, 2007).