Presentation on theme: "New imaging strategies in Degenerative Disease of the Intervertebral Disks Functional Spine Imaging."— Presentation transcript:
New imaging strategies in Degenerative Disease of the Intervertebral Disks Functional Spine Imaging
Introduction Current MR imaging often fails to identify cause of pain Surgical management of DDD changing –Biochemical targets for disk therapy –Earlier intervention Imaging goals in transition
Functional imaging Great potential, but limited validation –MRS, –measurement of T2 relaxation times, –measurement of T1 rho, –dynamic imaging, –fMRI of the spinal cord –measurement of CSF flow and pressure.
MRS Lactic acid in the disk correlates with painful degenerating disks MRS noninvasively and effectively quantifies glycosaminoglycans and lactate in the disk MRS effectively distinguishes pain producing from non-pain producing disks Additional studies are needed.
MRS peaks in disk tissue
L4/L5 Disc Processing of raw MR spectral data RAW SIGNAL PROCESSED PG LA L5/S1 Disc
Intervertebral disk Lactic acid/PG
T2 relaxation times and T1 rho Clinical scanners provide the pulse sequences required to measure T2 relaxation times and T1 rho Provide a quantitative measure that correlates with the degenerative stage of the disk T2 relaxation times a proxy measurement of disk water Measure changes in the disk over time Promise to distinguish early degenerative changes from age-related changes T2 relaxation times decline slowly with age and more rapidly with degeneration Acquisition T2 data requires 6 minutes; T1 rho, 30 minutes.
T2 relaxation time image
Contour map of T 2 relaxation times in normal lumbar disk
Distribution of water in intervertebral disk T 1 rho Johannessen W et al. Spine 2006
Correlation of T 2 relaxation time to cadaver disk water content Marinelli N et al. submitted
Correlation of relaxation time to GAG content
MR images, T2 maps, and water content maps Marinelli et al, unpublished data.
Change in T2 relaxation times with degeneration
Change in T2 relaxation times with aging
Dynamic imaging Biomedical techniques measure rotations of vertebrae MR, CT measure rotation of lumbar vertebrae Dynamic MRI: the application of a load or force to the spine with pre-acquisition of images Relative rotation a measure useful in selecting patients for a fusion procedure Dynamic imaging without measurement: still under evaluation.
Measuring axial rotations of the lumbar spine with CT or MR 1.Table insert 2.Axial images 3.Application of standardized rotation to the spine 4.Repeat axial images 5.Calculation of rotation between vertebrae from image pairs
CT measurement of vertebral rotation correlated to reference method
Rotation measurement following L4/5 fusion Rotations for lumbar motion segments L1/L deg L2/ L deg L3/L deg L4/L deg L5/S deg
Axial loading of the spine
fMRI Demonstrates activation in the spinal cord secondary to motor and sensory functions Greater technical difficult that cerebral fMRI.
L L4 Patrick W. Stroman, PhD, University of Manitoba Activation in the spinal cord from thermal stimulation of R L4 dermatome
Activation of the spinal cord from tactile stimulation Walter Backes PhD, University Hospital Maastricht
Visualization of CSF flow and pressure Evaluation of Chiari I patients Measure CSF flow and pressure Selection of patients for cranio-occipital decompression Explanation of pathogenesis of syringomyelia
CSF flow in the Chiari I malformation
Conclusions Future promises minimally invasive procedures that reverse intervertebral disk degeneration Require new imaging strategies, especially for patients with early disk degeneration Functional imaging tools include many different techniques including MRS, measurement of disk water, dynamic MRI Functional imaging tools include many different techniques including MRS, measurement of disk water, dynamic MRI