The Value of Thermography as a Clinical Imaging Diagnostic Test:

frared thermography, mapped 32 dermatome segments on the body’s surface that approximated the areas of innervation of the major peripheral nerves. He studied 32 healthy subjects and 30 patients with peripheral nerve impairment. In normal persons, he found the skin temperature difference between sides of the body to be stable, varying only 0.24C + 0.073C. In contrast, patients with peripheral nerve injury had skin temperature deviations on an average of 1.55C (p < 0.001) in segments innervated by a damaged nerve. Although some of the above-noted studies were quoted in the OHTA report, however, the logical conclusion was not drawn-that, according to most papers, thermography can distinguish normal from abnormal and that the range of temperature differences between sides of the body in normals was clearly quantified. Instead, the report lumped the assessment of thermography together with another methodology, using thermocoupled thermometers,‘” and did not base its conclusions on the individual merits of the two different techniques. Obviously, thermocoupled thermometers are not equivalent to a computerized thermographic imaging unit. The thermocoupled unit would include an impractical number of often haphazard spot temperatures in an attempt to obtain a composite imaging pattern. Thermocouples are also subject to other drawbacks, including stem effect, lead length, variable surface contact, and pressure effects.” Similar findings were obtained by Goodman et a1. Feldman and Nickoloff, using liquid crystal thermography of the cervical spine and upper extremities of 100 asymptomatic subjects, concluded that an asymmetry of 0.6C was presumptive evidence of abnormality and that an asymmetry of greater than 1C was definitely abnormal. 6 Another paper, by Ash,” claimed that thermography was unreliable in measuring heat emission patterns from curved living skin surfaces. However, the artifact noted by Ash was probably due to specular reflection in his equipment, as indicated by Anbar.