Radiology Section - Thermography

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Thermography is a non-invasive imaging technique, which is intended to measure temperature distribution of various organs and tissues. The infrared radiation from the tissue reveals temperature variations by producing brightly colored patterns on a liquid crystal display. Interpretation of the color patterns is thought to assist in the diagnosis of many disorders such as breast cancer, Raynaud's phenomenon, digital artery vasospasm in hand-arm vibration syndrome, impaired spermatogenesis in infertile men, degree of burns, deep vein thrombosis, gastric cancer, tear-film layer stability in dry-eye syndrome, Frey's syndrome, headaches, low-back pain, reflex sympathetic dystrophy, and vertebral subluxation. Thermography is also thought to assist in treatment planning and procedure guidance such as identifying restricted areas of perfusion in coronary artery bypass grafting, assessing response to methylprednisone in rheumatoid arthritis, and locating high undescended testicles.

The American Chiropractic Association suggests that high-resolution infrared imaging is of value in the diagnostic evaluation of patients when the clinical history suggests the presence of one of the following situations (17):

• Early diagnosis and monitoring of reflex sympathetic dystrophy syndromes
• Evaluation of spinal nerve root fiber irritation and distal peripheral nerve fiber pathology for detection of sensory/autonomic dysfunction
• Evaluation and monitoring of soft tissue injuries, including segmental dysfunction/subluxation, sprain and myofascial conditions (strains and myofascial pain syndromes) not responding to clinical treatment
• Evaluation of the physiological significance of equivocal or minor anatomical findings seen on myelogram, computed tomography (CT) and/or magnetic resonance imaging (MRI)
• Evaluation of feigned disorders

Thermography can include various types of telethermographic infrared detector images and heat-sensitive cholesteric liquid crystal systems.

Policy/Criteria

Thermography is considered investigational for all indications.

Scientific Background

This policy is based on a 1987 BlueCross BlueShield Association Technology Evaluation Center (TEC) assessment which focused on three categories of indications (2):

The first and second categories can be diagnosed with the same set of alternative methods, including: physical neurological examination, computerized tomography (CT), electromyography (EMG), myelography, nerve conduction studies, magnetic resonance imaging (MRI), and surgical exploration.

From a review of the scientific literature on thermography, the following key questions emerge:

Neuromuscular Conditions Associated with Spinal Pain: Electronic Infrared-Thermography

Infrared thermography has seen its most extensive use in these conditions. The main disorder targeted by studies in this group is spinal nerve root irritation or radiculopathy. It can occur at the cervical, thoracic, lumbar and sacral levels. Seven studies addressed this condition. (3-9) Thermography was compared to one of several of the alternative diagnostic methods mentioned above. Findings were reported in various formats, including sensitivity, specificity, accuracy or percent agreement (a composite figure which combines sensitivity and specificity, and correlations).

The general aim of these studies was to show an acceptable rate of agreement between thermography and alternatives, with special emphasis on the low rate of false negatives. They found that thermography had a comparable level of accuracy relative to its alternatives. However, this did not address the low specificity of thermography. The studies did not address the question of whether thermography added any significant information to the differential diagnostic process that could not be derived through physical examination of the patient.

Overall, the manner in which these studies were reported lacked depth and detail. In addition, these studies were not subjected to peer review. Methodological problems included small numbers of study subjects (from which it was difficult to draw conclusions), no mention of patient selection criteria, incomplete reporting of results, and incomplete or no mention of testing protocol.

Neuromuscular Conditions Associated with Spinal Pain: Liquid Crystal Thermography (LCT)

Four studies in the above category were included in the TEC assessment, and the results were variable. Neuman and colleagues compared LCT EMG, myelography, physical findings and CT in patients with chronic lumbosacral pain. (10) Accuracy ranged from 54-58% with varying number of false negatives. Similarly, Mills and colleagues related LCT to EMG, myelography, CT and surgical findings with obtained accuracy rates of 41-53%. (11) Adams and Lloyd found correlations with EMG, CT and myelography ranging from 40-94% in lumbar, thoracic and cervical patients. (12) Pochaczesky and colleagues found LCT to have better sensitivity than myelography in patients with sacral, lumbar and cervical disorders. (13) This last positive finding provides insufficient evidence from which to conclude that LCT is a useful technique.

Peripheral Nerve Injury/Reflex Sympathetic Dystrophy (RSD)

RSD is a chronic impairment of sympathetic function marked by burning pain, paresthesias, signs of vasomotor instability and disuse atrophy. It is sometimes, but not always, preceded by an identifiable event of peripheral nerve injury. However, it is assumed that its etiology is the disruption of a peripheral nerve. Early diagnosis of RSD has been unsuccessful - no reliable method of detection exists prior to the development of trophic changes. Three studies examined the use of infrared thermography in evaluating peripheral nerve injury, the earliest of which was a large-scale effort aimed at comparing thermography with EMG, myelography and nerve conduction studies. (14) The authors found a specificity rate of 89% (11% false negatives). In a smaller investigation, a high rate of correspondence was found between positive thermograms and the combined results of alternative tests (history, neurological examination, x-ray, EMG and myelography). (15) Another study was somewhat ambiguous in that the report failed to mention the alternative means with which peripheral nerve injury was determined. (16) The author simply identified a group of nerve-injured patients and showed a high rate of thermal asymmetry in the appropriate skin sites. Given the small number of empirical studies, it cannot be definitely concluded that infrared thermography is useful in detecting peripheral nerve injury/RSD.

Breast Cancer Screening

Thermography has been proposed as an alternative method of breast cancer screening. Currently, the gold standard for breast cancer screening is mammography; therefore, sensitivities, specificities, and positive and negative predictive values of thermography need to be compared against those of mammography in order to evaluate whether or not thermography is equivalent or superior to mammography. There are no published studies in the peer-reviewed scientific literature comparing the two screening techniques. Furthermore, there are no national published evidence-based practice guidelines which endorse thermography as the appropriate method of screening for early detection of breast cancer.

Other Conditions

Several additional conditions (psychogenic pain, carpal tunnel syndrome, trigger points, temporomandibular joint disease, stress fractures, amputation complications) have been studied via thermography, each of which is represented by too little empirical research to support any clear conclusion regarding diagnostic utility.

Practice Guidelines

In 1998, the Council on Chiropractic Practice issued a document that stated that thermography was an established method to detect temperature changes in spinal and paraspinal tissues related to vertebral subluxation. (17) However, this recommendation is based on expert opinion and literature support of observational, pre-post, and/or case studies but not controlled studies.

The Reflex Sympathetic Dystrophy Syndrome Association and the International Research Foundation for RSD/CRPS issued guidelines for the treatment of reflex sympathetic dystrophy and complex regional pain syndrome. (18,19) Each of these guidelines indicates thermogram may be used to assist in the diagnosis of RSD/CRPS. However, neither guideline lists supporting evidence for its conclusion.

The American Medical Association (20), the American College of Radiology (21-23), the American College of Obstetricians and Gynecologists (24), American College of Occupational and Environmental Medicine (25), the National Headache Foundation (26) and the American College of Neurology (27) issued policy statements or other documents that specifically do not recommend or endorse thermography as a diagnostic technology.  Additionally, the Work Loss Data Institute, in its pain management guidelines, lists thermography under the category of interventions that are either not currently recommended or not specifically included as major recommendations. (28)  The Ottawa Panel reported no benefit for thermography used for the diagnosis of rheumatoid arthritis. (29)

Summary

There is insufficient evidence in the peer-reviewed published literature to reach conclusions concerning the effects of thermography on health outcomes for any indication. The scientific literature is inadequate to validate the clinical role of thermography; no published studies demonstrate how the results of thermography can be used to enhance patient management and improve patient health outcomes. An updated search of the MEDLINE database through May 12, 2008 identified no additional published studies which alter this determination.

References

1. BlueCross BlueShield Association Medical Policy Reference Manual, Policy No. 6.01.12
2. TEC Assessment, Thermography, 1987; BlueCross and BlueShield Association Technology Evaluation Center. Vol 2
3. Wexler CE. Neuromuscular thermography: its past, present status, and future prospects. Postgraduate Medicine 1986;spec. ed.:9-20
4. Weinstein SA, Weinstein G. A review of 500 patients with low back complaints: comparison of five clinically accepted diagnostic modalities. Postgraduate Medicine 1986;spec. ed.:40-3
5. Weinstein SA, Weinstein G. A clinical comparison of cervical thermography with EMG, CT scanning, myelography, and surgical procedure in 500 patients. Postgraduate Medicine 1986;spec. ed.:44-6
6. Goldberg GS. Thermography and magnetic resonance imaging correlated in 31 cases. Postgraduate Medicine 1986;spec. ed.:54-8
7. Gillstrom P. Thermography in low back pain and sciatica. Archives of Orthopedic and Trauma Surgery 1985;104:31-6
8. Hubbard J, Maultsby J, Wexler CE. Lumbar and cervical thermography for nerve fiber impingement: a critical review. Clinical Journal of Pain 1986;2(2):131-7
9. Uricchio JV, Walbroel CE. Blinded reading of electronic thermography. Postgraduate Medicine 1986;spec. ed.:47-53
10. Neuman RI, Seres JL, Miller EB. Liquid crystal thermography in the evaluation of chronic back pain: a comparative study. Pain 1984;20:293-305
11. Mills GH, Davies GK, Getty CJM and Conway J. The evaluation of liquid crystal thermography in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis. Spine 1986;11(5):427-32
12. Adams WJ, Lloyd JT. Empirical evaluation of the chronic pain diagnosis. Postgraduate Medicine 1986;spec. ed.:86-89
13. Pochaczesky R, Wexler CE, Meyers PH, Epstein JA, Marc JA. Liquid crystal thermography of the spine and extremities. Journal of Neurosurgery 1982;56:386-95
14. Uematsu S, Hendler N, Hungerford D, Long D, Ono N. Thermography and electromyography in the differential diagnosis of chronic pain syndromes and reflex sympathetic dystrophy. Electromyographic and Clinical Neurophysiology 1981;21:165-182
15. Pulst SM, Haller P. Thermographic assessment of impaired sympathetic function in peripheral nerve injuries. Journal of Neurology 1981;226:35-42
16. Uematsu S. Thermographic imaging of cutaneous sensory segment in patients with peripheral nerve injury. Journal of neurosurgery 1985;62:716-20
17. Council on Chiropractic Practice.  Clinical Practice Guideline Number 1: Vertebral Subluxation in Chiropractic Practice.  1998 (updated 2003).  www.ccp-guidelines.org/guideline-2003  (Verified 05/12/08)
18. Reflex Sympathetic Dystrophy Syndrome Association (RSDSA). Clinical practice guidelines (second edition) for the diagnosis, treatment, and management of reflex sympathetic dystrophy/complex regional pain syndrome (RSD/CRPS). Milford (CT):  Reflex Sympathetic Dystrophy Syndrome Association (RSDSA); 2002 Feb.  46 p
19. International Research Foundation for RSD/CRPS. Reflex sympathetic dystrophy/complex regional pain syndrome. 3rd ed. Tampa (FL): International Research Foundation for RSD/CRPS; 2003 Jan 1. 48 p
20. AMA policy statement. H-175.988 Thermography Update.  www.ama-assn.org/apps/pf_new/pf_online?f_n=browse&doc=policyfiles/HnE/H-175.988.HTM  (Verified 05/12/08)
21. Seidenwurm DJ, Brunberg JA, Davis PC, et al. Expert Panel on Neurologic Imaging. Myelopathy. [online publication]. Reston (VA): American College of Radiology (ACR); 2006. 11 p. (Verified 5/12/08)
22. Bradley WG Jr, Seidenwurm DJ, Brunberg JA, et al. Expert Panel on Neurologic Imaging. Low Back Pain [online publication]. Reston (VA): American College of Radiology (ACR); 2005. 7 p.
23. Polak JF, Yucel EK, Bettmann MA, et al. Expert Panel on Cardiovascular Imaging. Suspected lower extremity deep vein thrombosis. [online publication]. Reston (VA): American College of Radiology (ACR); 2005. 5 p. (Verified 5/12/08)
24. American College of Obstetricians and Gynecologists (ACOG). Breast cancer screening. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2003 Apr. 12 p. (ACOG practice bulletin; no. 42). (Verified 5/12/08)
25. Low back complaints. Elk Grove Village (IL): American College of Occupational and Environmental Medicine (ACOEM); 2004. 41 p
26. Martin V, Elkind A. Diagnosis and classification of primary headache disorders. In: Standards of care for headache diagnosis and treatment. Chicago (IL): National Headache Foundation; 2004. p. 4-18
27. American College of Neurology. Assessment: Thermography in Neurologic Practice. Report of the American Academy of Neurology Therapeutics and Technology Assessment Subcommittee. Neurology 1990;40(3 pt 1):523-5
28. Work Loss Data Institute. Pain (chronic) Corpus Christi (TX); 2003 (revised 2007). 65 p
29. Ottawa Panel evidence-based clinical practice guidelines for electrotherapy and thermotherapy interventions in the management of rheumatoid arthritis in adults. Phys Ther 2004;84(11):1016-43

Cross References

None

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