Clinical question: PLEASE INCLUDE SI JOINTS., s/p Left hip arthroscopy, labral repair 8/26/14, continued low back SI joint pain, has had 2 SI joint injections without relief. Evaluate SI joints and evaluate for disc injury. Pain is on left sideSigns and Symptoms: Continued left side hip, SI joint pain. Nonenhanced lumbar MRI:There is normal anatomical alignment of vertebral column.The signal intensity of vertebral column is unremarkable changes secondary to discogenic disease.Unremarkable medial and most visualized thoracic spine and thoracic cord from T10 inferiorly.T12-L1 is unremarkable.L1-L2 demonstrates advanced disc disease and significant loss of disc height, there is shallow ventral disc osteophyte with resultant partial effacement of subarachnoid space however without central spinal stenosis. There is also no evidence of neural foraminal compromise.L2-L3 is unremarkable.L3-L4 is unremarkable.L4-L5 demonstrate mild degenerative changes without spinal stenosis or neural foraminal compromise.L4-L5 demonstrate mild disc disease and loss of disc height, mild bilateral ligamentum flavum and facet hypertrophic changes. No spinal stenosis or neural foraminal compromise. There is a linear T2 increased signal intensity within the annulus of the disc in the midline and consistent with an annular fissure.There is a shallow broad-based disc protrusion with resultant effacement of ventral subarachnoid space and without detectable mass effect on the thecal sac.L5-S1 demonstrate mild disc disease and loss of disc height, mild bilateral (L>R) facet and ligamentum flavum hypertrophy. No evidence of a spinal stenosis or neural foraminal compromise.Sacral spine demonstrate a left sided CSF signal intensity expansile lesion proximal left S2 neural foramina which a benign Tarlov cyst or perineural cyst. This finding demonstrate mass effect on the left S1 nerve root and its resultant flattening deformity which is best appreciated on axial T2 series 701 on images 2 through 4.Perispinal soft tissues demonstrate a smaller left psoas muscle compared to right and suspected of mild atrophy.Visualized SI joints demonstrate no appreciable degenerative changes or signal abnormality. On the left there is a well demarcated and primarily fatty signal intensity lesion measuring approximately 11 x 14 mm in transaxial dimensions. The finding is contiguous with the SI joint and medial well-demarcated cortical rim and is not associated with any adjacent marrow signal changes or soft tissue mass. Finding is consistent with benign fatty deposit and possibility of a benign hemangioma should also be considered. The clinical significance of this finding is questionable. This finding was also present on prior lumbar MRI exam without additional change.
1.Nonenhanced MRI of the lumbar spine demonstrate degenerative changes without evidence of central spinal stenosis or clinically significant neural foraminal compromise as detailed above. Small central disc protrusion at L5-S1 without mass effect on the thecal sac. Perineural cyst on the left at S2 neural foramina with resultant expansion of foramina and mass effect / flattening of left S2 nerve root. 2.Unremarkable SI joints. Fatty signal intensity lesion inseparable from the left SI joint space could represent benign fatty deposit or a benign hemangioma as detailed above..