Interventional Pain Management from a Diagnostic Imaging Point of View

1. Interventional Pain Management from a Diagnostic Imaging Point of View Arthur S. Watanabe, MD, FIPP Friday, Sept 13, 2013 Washington Assn of Nurse Anesthetists

2. Art Watanabe, M.D., Pharm.D. Medical Director Open MRI DiagnosticsSpinal Diagnostics, PLLCClinical Assistant Professor of RadiologyUniversity of WashingtonSpokane, Washingtonwww.openmridiagnostics.com Spinal Diagnostics, PLLC 2

3. Disclaimer Medical Director, Spinal Diagnostics and Open MRI Assistant Clinical Professor, Radiology, University of Washington School of Medicine Board Certified ABR ABIPP Member: ASIPP, ISIS, ASSR, ASNR, NASS Past Board Member, ASIPP President, Washington Society of Interventional Pain Physicians Proctor for Advanced Neuromodulation Systems, Boston Scientific Spinal Diagnostics, PLLC 3

4. Lecture Objectives: • Description of various aspects of imaging of the spine • Radiography • Myelography • Computed Tomography • SPECT Scans

5. Imaging for Interventional Pain Physicians

6. Imaging for Interventional Pain Physicians

7. Radiography

8. Radiography Physics – X-ray Conversion electron K.E.  E.M.R. Electrons boiled off x-ray tube hit Tungsten anode  X-ray X-rays generated by 2 processes: General radiation Characteristic radiation Spinal Diagnostics, PLLC 8

9. Lumbar Radiography Advantages • High spatial resolution • Good bone contrast resolution • Wide availability • Fast, easy imaging • Non-claustrophobic • Inexpensive

10. Lumbar Radiography Weaknesses • Poor-fair soft tissue contrast resolution • Only four densities • Fat, water, air, bone • Radiation dose • Variation in techniques by facility

11. Lumbar Facet with Gadolinium Open MRI Diagnostics 11

12. Vertebral Cement Augmentation Open MRI Diagnostics 12

14. Myelography 14

15. Myelography Radio-opaque contrast is injected into the thecal sac to assss its contents, e.g. spinal cord, nerve roots. Approx 350,000 myelograms/year in U.S. 1913 – Luckett incidentally noted vetricular system was visualized on a post- traumatic skull x-ray. 1918 – Walter Dandy, MD Johns Hopkins neurosurgeon air myelography and air encephalography.

16. Lumbar Myelography Strengths • Problem solving tool • Nerve roots • Intradural lesions • Arachnoiditis • Alternative for patients unable to have MRI

17. Myelography Weaknesses • Intradural imaging • Invasive with attendant risks • Radiation • Variation in techniques by facility • Variation in readings by radiologists

18. Myelography Technique • Fluoroscopic guidance • 25 or 26 G 3 ½ in Quincke tip • L2/3 interlaminar space • Bevel medial or lateral • Check lateral fluoro • 12-15 cc nonionic iodinated contrast 240M

19. Lumbar Myelography Complications • Spinal headache • Pneumocephalus • Nerve root damage • Contrast reaction • Infection, hematoma

20. Computed Tomography 20

21. CT Scan - Evolution CT one of the greatest radiology innovations since the discover of X-rays. X-sectional imaging provided diagnostic information improved visualization of disease. Godfrey Hounsfield, British electronics engineer with EMI Company, builds a CT scanner between 1969 and 1972. Allan Cormack, South African nuclear physicist, in 1963 described the mathematical basis for constructing a CT scanner.

22. Spiral CT Imaging Volume Scanning Patient table translates thru scan gantry while x-ray tube rotates 360º continuously. X-ray produces a spiral path thru the body resulting in a data volume acquisition of three dimensional picture elements, i.e. voxels.

23. CT Lumbar Spine: Strengths • High spatial resoln • Good bone contrast resoln • Wide availability • Fast, easy imaging • Non-claustrophobic • Multiplanar, 3D reformations

24. CT Spine: Weaknesses • Fair soft tissue contrast resolution • Radiation dose • Variation in techniques by facility • Variation in readings by radiologists

25. CT Scan - Image Processing Axial cross-sectional images stored in digital form processed immediately. CT measurement of geometrical parameters E.g., distance, area, angle, volume and density. Geometrical parameters more accurately defined with CT than in conventional radiography superimposition and distortion not present

26. Magnetic Resonance Imaging

27. MRI Scan - Evolution 1972 Damadian files patent for a NMR body scanner entitled Apparatus and Method for Detecting Cancer in Tissue. 1974 Damadian receives U.S. Patent #3,789,832. 1977 Dr. Damadian develops the first MRI scanner of the human body Indomitable installed in the Smithsonian Institution.

28. MRI Scan - Evolution 1977 the Indomitable produced the first human MRI image.

29. MRI Sequences What is fat doing? What is CSF doing? Spinal Diagnostics, PLLC 29

30. MRI Sequences T1 Fat Bright H2O Dark C T2 Fat Dark H2O Bright FSE T2 Fat, H2O bright STIR Only H2O bright Spinal Diagnostics, PLLC 30

31. Imaging the Spectrum of Facet Joint Pathology

32. Normal Facet Joints • Joint Space • Joint Margins • Articular cartilage • Periarticular soft tissues

33. Advanced Facet Disease • Articular cartilage loss • Subchondral bony eburnation • Marginal hypertrophic changes, spurring • Effusion • Atrophy of multifidi and erector spnae muscles

34. Advanced Facet Disease • Absence of cartilage • Bone on Bone • Marginal hypertrophic changes • Deconditioning of multifidi and erector spinae m.

35. Unilateral Facet Disease • Left side normal • Right side • Articular cartilage loss • Joint effusion

36. Facet Synovitis • Prominent effusion • Note: medial ligamentum flavum hypertrophy • Paraspinous muscles preservered

37. Paravertebral Soft Tissue • Gadolinium contrast enhancement • Periarticular soft tissue • Medullary bone marrow • High clinical correlation with pain generator

38. Unilateral Facet inflammation • Articular cartilage • Gadolinium contrast enhancement • Medullary bone marrow • Periarticular soft tissues

39. Facet Marrow Edema • Medullary bone marrow edema • Indicator of inflammation • High clinical correlation with pain generator

40. The positive predictive value of isotope lumbar SPECT scans to RF rhizhtomy response Unpublished Study

41. Study Design and MR • Retrospective chart review study • Initial assessment with diagnosis of lumbosacral arthrosis • Lumbar SPECT scan • Facet block: (0.4 cc 0.5% Marcaine, 0.4 cc Depo) • MBB block: (ea branch 0.4 cc 0.5% Marcaine) • RF Rhizhotomy (85 Degrees 105 sec) x 3 • Follow up • Methods • Total: 57 patients • Age: Range: 32 – 80 yrs, Mean: 67 yrs • Sex: M 30 F 27

42. Preliminary Results: SPECT

43. Preliminary Results: Clinical Exam

44. Preliminary Conclusion • Concordant positive lumbar spine bone scans are predictive of good clinical response to RF rhizhotomy. • Clinical diagnosis of facet pain generator just as sensitive as lumbar spect scans • Lumbar spect scans while predictive may be unnecesary imaging and costs.

45. ANYBODY MISS THIS GUY? • 'Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it'   - Ronald Reagan

46. Spinal Imaging: Caveats High tech physical exam It’s just an image Doesn’t tell you where the pain is coming from Lots of false positives and false negatives Open MRI Diagnostics 46

47. Spinal Imaging: Caveats High tech physical exam It’s just an image Doesn’t tell you where the pain is coming from Lots of false positives and false negatives Open MRI Diagnostics 47

48. The truth about imaging The pictures lie The pictures rarely tell you what the pain generator is Over reliance on imaging = false sense of security Open MRI Diagnostics 48

49. Which is the more important imaging modality here? Open MRI Diagnostics 49

50. Only the needle knows… Open MRI Diagnostics 50