THE ROLE OF INFRARED THERMAL IMAGING
IN ELECTRICAL INJURIES
Hooshang Hooshmand, M.D., Masood Hashmi, M.D. and Eric
Neurological Associates Pain Management Center
1255 37th Street, Suite B
Vero Beach, FL 32960
In our study of 411 consecutive
Electrical injury (EI) patients (in publication) , the disease followed a
stereotypical pattern. The electricity enters, and passes through the path of
the least resistance [1,2]. This path consists of oxygenated, rapidly
circulating arterial blood. In its wake the electricity damages the
thermoreceptor sensory nerves in the wall of blood vessels. As a result, the
electricity causes neuropathic pain, complex regional pain syndrome
spinal cord dysfunction , myelogenic seizures and limbic system dysfunction
As far as we are aware, the only disease in medicine with
exclusive, sin equa non thermal changes on Infrared thermal imaging
(Thermography) is electrical injury. The most characteristic thermographic
finding in EI is the "button hole" sign (Fig.1) at points of entrance or exit of
electricity. The epicenter of the damage area is hyperthermic, surrounded by
concentric hypothermic isotherms (Fig.1). The hypothermic surround is so
intense that it conceals the small central hyperthermia. It requires impeccable,
and detailed technique to identify the central "button hole" hyperthermia (Fig.1). Limiting the test to standard technique, and not increasing the sensitivity,
will show nothing but a hypothermic extremity masking the "button hole" sign.
The second typical thermographic finding in EI is hyperthermia in precordial and
posterior thoracic areas. This is due to the electrical injury involving the
richly innervated structure of cardiac sympathetic plexus. The thermographic
signs are important in diagnosis of EI injuries in face of EMG/NCV and MRI tests
being invariably normal. EMG/NCV are positive in less than 5%, and MRI in less
than 2% of cases .
Fig. 1 - Central hyperthermic areas of entrance and exit in
electrical injury. The permanent hyperthermic damage is surrounded by
vasoconstrictive hypothermia. Only after increasing the thermal sensitivity
(right) the lesions were identified. This "button hole" sign is exclusively seen
in electrical injury.
1. Hooshmand H, Petrilla F, Phillips E.M.: Long term effects of
electrical injuries. Industrial lightning strikes: A study of 411 patients. In Publication.
2. Hooshmand H, Radfar F, Beckner E: The neurophysiological
aspects of electrical injuries. Clin Electroencephalography 20:111-120, 1989.