A Critical Look at Thermography

Stephen Barrett, M.D.

Thermographic devices portray heat emission from body surfaces as images that the practitioner interprets. The images may be in color or in black and white, and may be accompanied by displays of various calculations. Each color or shade represents a specific temperature level.

One type of device converts the radiated heat (infrared energy) into electronic signals that are amplified and transmitted to a monitor and/or videotape. Liquid crystal display devices exist but are not as popular. Some devices produce a printout that can be shown to the patient. An infrared thermographic examination typically costs hundreds of dollars.

 

Promotional Claims

Chiropractors who use thermography typically claim that it can detect nerve impingements or "nerve irritation" and is useful for monitoring the effect of chiropractic adjustments on subluxations [1]. One ad I have seen claimed that thermography provides "a picture of pain" and "helps the doctor and patient find and describe 'the reason for pain.'" One manufacturer has stated that thermography "attracts patients who do not wish to be x-rayed." Another has stated that it provides "comprehensive and substantive proof that each chiropractic adjustment provided some correction of a patient's problem." Chiropractors have even set up an American Chiropractic Board of Thermography, which offers "certification" in the procedure. Some chiropractors refer to thermograph as digital infrared imaging.

Thermography is also promoted by the American College of Clinical Thermology (ACCT), which offers training and several "certification" programs in "clinical thermography." According to its Web site:

Medical [Digital Infrared Thermal Imaging] is a monitor of thermal abnormalities present in a number of diseases and physical injuries.It is used as an aid for diagnosis and prognosis, as well as therapy follow up and rehabilitation monitoring, within clinical fields that include Rheumatology, neurology, physiotherapy, sports medicine, oncology, pediatrics, orthopedics and many others.

Results obtained with medical DITI systems are totally objective and show excellent correlation with other diagnostic tests [2].

The ACCT site also lists 76 alleged "indications for thermographic evaluation" and about 120 "approved clinics" in the United States. One such clinic is run by Terry Sorbe, of Burnsville, Minnesota, a Clayton College of Nutrition graduate who practices "nutrition, herbology & homeopathy" and claims that thermography "detects breast cancer 10-12 years before mammography." [3]

What's Wrong with This Picture?

The scientific view is that thermography is, at best, a research tool that would not yield useful information for day-to-day chiropractic or medical practice. In 1989, the American Academy of Neurology (AAN) issued a position paper stating that thermography had not been proven useful as a screening test for patients with back or neck pain and that better tests are available for most other purpose [4]. In 1990, the American College of Radiology resolved that "thermography has not been demonstrated to have value as a screening, diagnostic, or adjunctive imaging tool." [5] In 1993, the American Medical Association concluded:

In 1994, after reviewing additional studies, an Agency for Health Care Policy and Research panel concluded:

The one study meeting review criteria found that thermography did not accurately predict either the presence or absence of lumbar nerve root compression found at surgery. In addition, several studies have shown thermography of the lower limbs as abnormal in a substantial proportion of [symptom-free] subjects with back problems. Based on the available research evidence, thermography does not appear effective for diagnosing low back problems [7].

No published studies demonstrate how the results of thermography can be used to enhance patient management and improve patient health outcomes. Therefore insurance programs are very unlikely to cover it. In 1989, the Office of Health Technology Assessment concluded:

Thermography lacks sensitivity, specificity, or predictive value. Unassailable data are lacking to indicate that thermography provides a useful guide to monitor the effect of treatment of any disease entity. The evidence suggests that thermography may only confirm the presence of a temperature difference, that other procedures are needed to reach a specific diagnosis, and that thermography may add little to what physicians already know based on history, physical examination, and other studies [8].

Based on this report the Health Care Financing Administration (now called the Center for Medicare and Medicaid Services) excluded Medicare coverage of thermography [9].

Aetna's Clinical Policy Bulletin states:

Aetna considers thermography (temperature gradient studies) experimental and investigational because available medical literature indicates thermography to be an ineffective diagnostic technique. . . .

The scientific evidence suggests that thermography may only confirm the presence of a temperature difference, and that other procedures are needed to reach a specific diagnosis. Thermography may add little to what doctors already know based on history, physical examination, and other studies [10].

In 1990, A Michigan judge ruled against two chiropractors who had sued an insurance company for denying coverage of thermographic scannings. In an 86-page opinion, the judge concluded that "thermography is not scientifically valid to monitor physiology to determine subluxations or misalignments." [11] In explaining his conclusion, the judge summarized the testimony of the expert witness (E. James Potchen, M.D., a board-certified specialist in radiology and nuclear medicine) whom he found "most eloquent":

Thermography has no utility in diagnosing nervous system disorders relating to the spine nor in diagnosing nerve interference. Thermography has no efficacy in diagnosing the various definitions of subluxation given by Dr. Herfert and Dr. Hofmann. It also has no efficacy in diagnosing where a particular nerve or group of nerves is not functioning.

Basically, Dr. Potchen explained that the reason for this lack of efficiency is that because thermography measures regional differences in heat which are caused by variations in the microvascular blood supply, and because these various skin vascular beds open and close almost randomly in an effort to release heat, efforts to find correlations with neural regulation of the microvascular circulation have been unsuccessful.

In another case, tried in Maryland, the judge ruled that "Thermography is an invalid medical diagnostic procedure for the treatment musculoligamentous injuries, musculoskeletal disease and nerve root impingement." One of the experts witnesses on whom the judge relied was orthopedist Charles J, Ash, M.D. of Springfield, Missouri who had demonstrated in a clever experiment that thermographic imaging of curved surfaces such as the human body are unreliable. The judge reported:

Dr. Ash showed slides of a thermogram that was taken of a balloon filled with two liters of swater heated to 80 degrees Fahrenheit. The heat loss was factored and the balloon was stated to be comparable to a bald human head. Then, the balloon was rotated 90 degrees, 180 degrees, and 270 degrees and thermographically imaged in each position within 30 seconds. . . . The result showed four distinct colors on each rotation. The area closest to the camera was the warmest spot on each rotation. Because the thermogram shows diverse colors for each one degree Centigrade, the balloon represented a four-degree Centigrade range. The relatively uniform temperature should have reflected only one color. Dr. Ash believes that thermographic imaging equipment with its two-dimensional depictions does not accurately measure the rounded surface of a patient. The three-degree Centigrade margin of error is, as Dr. Ash reported, prohibitively high [12].

Although the judge's ruling was overturned on appeal [13], it was well-reasoned and remains a monument to good science. Moreover, Leonard C. Redmond, III, one of the attorneys who tried the case, told me that the information developed during the proceedings led insurance companies in Maryland to stop paying for thermography, and Medicare excluded coverage soon afterward [14].

Regulatory Action

The FDA regulates " Telethermographic systems" as Class I medical devices when used as an adjunct to other methods and as Class III devices when used alone for diagnostic screening [15]. Class I devices require 510(k) clearance, but class III devices require full FDA approval. So far, the FDA has ordered three companies to stop makingillegal claims for thermograpy devices:

The Bottom Line

Despite their lack of scientific support, colorful thermographic images are still used by many chiropractors as a tool for selling spinal adjustments, and some chiropractors offer free thermography as a screening device. You should assume that any chiropractor who does this will find something that needs treatment [24].

References

  1. Stillwagon G, Stillwagon BS. Objective proof: Thermography documents chiropractic efficacy. Today's Chiropractic 23(3):52-56, 1994.
  2. Indications for thermographic evaluation. ACCT Web site, accessed Aug 24, 2006.
  3. Our services. Terry Sorbe's US Nutrition Web site, accessed Aug 24, 2006.
  4. American Academy of Neurology Therapeutics and Technology Assessment Subcommittee. Assessment: Thermography in neurologic practice. Neurology 40:523-525, 1990.
  5. Substitute resolution No. 33: Efficacy of thermography. Passed by American College of Radiology House of Delegates, Sept 26, 1990.
  6. H-175.988 Thermography update. AMA Council on Scientific Affairs, 1993, reaffirmed 2003.
  7. Bigos SJ and others. Acute Low Back Pain in Adults, Clinical Practice Guideline No. 14. AHCPR Publication No. 95-0642. Rockville, MD: Agency for Health Care Policy & Research, 1994, p 65.
  8. U.S. Department of Health and Human Services (DHHS), Public Health Service, Office of Health Technology Assessment. Thermography for indications other than breast lesions. Health Technology Assessment Reports. DHHS Pub. No. PHS 89-3438. Washington, DC: U.S. Department of Health and Human Services; August 1989.
  9. Centers for Medicare and Medicaid Services. National Coverage Determination for Thermography. NCD #220.11. Effective December 21, 1992.
  10. Thermography. Clinical Policy Bulletin 0029, updated March 8, 2011.
  11. Tertzag K. Opinion. John Hoffman, D.C. and Richard Herbert vs. Auto Club Insurance Corporation. Wayne County (Michigan) Circuit Court Case No 85-500355 CZ, Aug 29, 1990.
  12. Kaplan JHH. Opinion. Sabatier v. State Farm Mutual Insurance Company. Baltimore Circuit Court, 1990.
  13. Sabatier v. State Farm Mutual Insurance Company, 323 Md. 232, 592 A.2d 1098 (1991), appeal after remand, 327 Md. 296, 609 A.2d 307 (1992).
  14. Redmond LC. Interview by Dr. Stephen Barrett, April 11, 2006.
  15. Telethermographic system. Code of Federal Regulations Title 21, Sec 884.2980 53 FR 1566, Jan. 20, 1988, as amended at 55 FR 48440, Nov. 20, 1990; 66 FR 46953, Sept. 10, 2001.
  16. Ulatowski TA. Warning letter to Bernard Amani, July 26, 2007.
  17. Ulatowski TA. Warning letter to Rose Thomas, N.D. Oct 26, 2009.
  18. Silverman S. Warning letter to Central Coast Thermography / Breast Health Imaging Centers, Jan 6, 2011.
  19. Premarket notification 510(k): Telethermographic camera, K033967, Dec 19, 2004.
  20. Silverman S. Warning letter to Dr. Peter Leando, April 4, 2011.
  21. Silverman S. Warning letter to Dr. Joseph Mercola, March 22, 2011.
  22. Schultz DG. 510(k) clearance letter for Meditherm Med2000 (#K003332), Feb 21, 2001.
  23. Tsouderos T. FDA warns doctor: Stop touting camera as disease sceening tool. Chicago Tribune, April 26, 2011.
  24. Homola S. Inside Chiropractic: A Patient's Guide. Amherst NY: Prometheus Books, 1999.

This article was revised on June 5, 2011.