ChiroView Presents Ian McLean, DC DACBR - Associate Professor, Department of Radiology, Palmer College of Chiropractic. As previously announced, for "Member Subscribers", I have in- place at the ChiroView Presents site a "Diagnostic Imaging Board" which is found under the "Talkin' Back" Section. Broadcasts are being submitted by several experts on the topic of Diagnostic Imaging, including Dr. McLean who I have known for many years. His expertise and integrity are second to none and I am proud to have him on-board. Here is what Dr. McLean has to say. . . Choices in Diagnostic Imaging - A quick reference 1. Conventional radiography, computerized tomography, magnetic resonance imaging and radionuclide scintigraphy are commonly utilized diagnostic imaging procedures in chiropractic practice. Appropriate use of an imaging study depends on understanding the physics basic to the diagnostic imaging device in conjunction with recognizing the anatomical and physiological constituents of the clinical condition in question. 2. MRI imaging is an imaging system that spatially localizes hydrogen protons within tissue 1 Since this element represents eighty percent of all atoms found in the human body and MRI is particularly sensitive in evaluating a wide range of anatomy inclusive of the brain, spinal cord, and joints. MRI is also particularly helpful in evaluating bone pathology through imaging of bone marrow. In chiropractic, MRI is the procedure of choice in evaluating the spine especially when neurological symptoms are present 2. 3. Computerized tomography uses x-ray. During the examination the radiographic tube rotates about the patient and the exiting photons are intercepted by an array of detectors. This information is spatially organized by a computer to create digitized axial tomographic images of the body. Computerized tomography should be considered when high resolution images of bone are required such as with fracture or bone tumor. Computerized tomography is an important procedure in evaluating soft tissue lesions such as potential malignancies of the chest and aortic aneurysm, conditions not uncommon in clinical practice. Radionuclide scintigraphy (bone scan) is a relatively non- invasive technology that utilizes the radiopharmaceuticals technetium tagged to phosphate compounds such as methylene diphosphanate (Tc-MDP). This examination is especially helpful in evaluating pathophysiological abnormalities of the skeletal system. Increased uptake of the radiopharmaceutical occurs in bone in conditions that have both an increased metabolic activity and blood supply. Lesions include tumors, infections, fractures, metabolic diseases, and joint diseases. In chiropractic practice, recognizing the extent and location of metastatic bone disease represents the most common use of a bone scan. Conventional radiography has a false negative report rate as high as 50% whereas, a bone scan only has a false negative rate of only 2%. Patients that present with back pain and a prior history of a primary malignancy such as of the breast or prostate might warrant a radionuclide bone scan to aid in the exclusion of metastatic bone disease. Importantly, follow up examination with other imaging devices will also be likely necessary inclusive of computerized tomography, conventional radiology and also MRI. Conventional radiology is the mainstay of diagnostic imaging studies. In skeletal imaging, the x-ray examination should normally precede most of the specialized imaging studies. With MRI in particular, combining the information from an x- ray examination can be particularly helpful in understanding skeletal pathologies and joint diseases. Choosing a diagnostic imaging study is also contingent on issues of cost, availability and on occasion medicolegal factors. Further, on occasion certain pathologies will necessitate multiple imaging studies to fully understand the ramifications of a condition. Regarding conditions listed below, MRI is the "Diagnostic Procedure Of Choice" unless otherwise stated. . . SPINE 1. Disc Herniation - CT also reasonably sensitive 2. Recurrent Disc 3. Post Operative Scar 4. Degenerative Disc Disease - CT also reasonably sensitive 5. Radiculopathy - CT also reasonably sensitive 6. Myelopathy - X-ray used as adjunctive 7. Multiple Sclerosis 8. Spinal Metastasis 9. Syringomyelia - CT also reasonably sensitive 10. Multiple Myeloma - CT also reasonably sensitive 11. Infections - CT also reasonably sensitive 12. Cord Tumors EXTREMITIES 1. Avascular Necrosis - X-ray insensitive early in disease 2. Cruciate Ligament Tears - CT used as adjunctive 3. Meniscal Tears 4. Osteochondritis Desicans - CT used as adjunctive 5. Post Trauma - X-ray procedure of choice although MRI very sensitive 6. Chondomalacia Patella - insensitive early in disease 7. Rotator Cuff Tear 8. Glenoid Labrum Tear - CT and arthrogram sensitive 9. Tendonitis 10. Joint Effusions - CT used as adjunctive 11. Cartilage Degeneration - CT used as adjunctive 12. Infection / Osteomyelitis - CT used as adjunctive 13. Tumor / Multiple Myeloma / Metastasis - CT used as adjunctive References. 1. Introduction to T1 and T2: what are they and why should I care? Russell A. Blinder, M.D. Applied radiology, November 1988 2. Lukin RR, Gaskill MF, Wiot JG. Lumbar herniated disc and related topics. Semin Roentgenol 1988; 2:100-105 To become a "Member Subscriber" and gain access to the ChiroView Presents site, just click http://www.ChiroViewPresents.com.