Infrared Imaging and Open Heart Surgery

Infrared Imaging and Open Heart Surgery

By Wayne Ruddock, Advanced Infrared Resources, 177451 Bastanchury Rd, Suite 100D Yorba Linda, CA, Ph 250-579-2141

Introduction:
The study of temperature has been associated with health and the human body as far back as the 1st century BC. At that time the Greek philosopher Hypocrites, who is considered the father of medicine, used the sense of touch in relation to skin surface temperature anomalies to determine the "health" of
his patients, and to assist in the diagnosis of disease. Even in today's modern world an elevated body temperature or a "fever" is often a key which aides in both diagnosis and treatment planning.

Infrared Imaging:
All objects above absolute zero, -459 F, give off infrared radiated energy as the result of the acceleration and deceleration of charged atomic particles at the surface of an object. This radiated energy is directly related to the temperature of the object. The higher the temperature, the higher the kinetic molecular energy, leading to increased molecular motion, which results in an increased level of infrared radiated energy. Infrared imaging can be defined as the detection and measurement of this radiated energy, with the information being displayed and stored for both real time and post collection analysis. In the beginnings of this technology in the early 1960's, this information was displayed on a black and white CRT and captured using black and white film. Today this information can be displayed in color or gray scale on a CRT or LCD display and can be digitally stored and then analyzed at a later time using powerful computer programs. Infrared Imaging Systems are currently available in 3 common wavelength bands. Cameras known as long wave systems detect radiated energy in the wavelength band between 8 and 14 microns. These systems are typically uncooled systems using a Focal Plane Array detector set up which gives high resolution gray scale or color images. These type of systems are the most commonly used cameras in industrial infrared applications. A second type of camera generally known as a short wave system detects energy in the 2 - 6 micron bandwidth. Today, the majority of these cameras require cooling, using either liquid nitrogen or a sterling cycle cooler to accomplish this task. The detector array is cooled to -196 Celsius, giving the cameras excellent thermal resolution. A new addition to the infrared imaging camera field in the last few years has been the Near IR system. The main use of this camera, which detects energy in approximately the .9 - 1.7 micron bandwidth, is in the telecommunications industry.

Infrared Imaging and Open Heart Surgery Today:
Infrared imaging in the past, has been confined mainly to the evaluation of external skin temperatures in a variety of applications. These uses have met with success in a number of publicized situations. For many years, Dr. Ernest M. Feiler, MD, has been working on a technique to prove the value of infrared imaging in open heart surgery. Dr. Feiler has patented this initiative and is currently involved in case studies, which are proving the effectiveness of this technique. Today, infrared imaging is proving its ability to assist the surgeon in making real time decisions during the open heart surgery procedure. It gives valuable information during the operation by showing the change in temperature
patterns on the heart as various procedures are performed. Dr. Feiler has indicated that the three main areas infrared imaging can be of assistance to the surgeon are as follows:

1. The use of infrared imaging in open heart surgery demonstrates unsuspected areas of inadequate myocardial perfusion, due to obstruction of the tiny branch arteries that do not show up on coronary arteriography, generally associated with adjacent myocardial infarction, diabetes mellitus, or old age. The goal is to correct this inadequate perfusion, when identified by infrared imaging during the operation, by the use of procedures such as of TransMyocardial Laser Revascularization, (TMLR).
2. In cases of multiple obstructions in one coronary artery, infrared imaging will show if a graft placed distal to one of the obstructions supplies the other parts of the artery as well, by antegrade or retrograde flow past the obstructions, and therefore produces adequate myocardial perfusion as seen by comparison of the myocardial perfusion in each area. By using infrared imaging to see this, the surgeon can then determine if further grafting into that artery is necessary.
3. Infrared imaging can demonstrate if there is partial sharing of perfusion beds between an artery whose graft has been completed graft and another artery that is being approached, due to the development of collateral vessels, or detour routes. This is suspected when the perfusion fluid of one artery flows out when another artery is opened, which then requires a graft to keep it from closing. Now, one can discover this, before the artery is opened, utilizing the line profile function on the infrared imaging instrument, and confirm it by comparison of the relative perfusion of the myocardium surrounding each artery. "Competitive Grafting", of necessity, decreases the flow through both grafts, thereby endangering the survival of both grafts. The AIR-MED system is a specifically designed package that allows high resolution of the relatively small chest cavity area, worked on during the open heart surgical procedure. This area is viewed from a remote position that in no way interferes with the surgical procedures. As this technique is non contact and non invasive, there is no adverse effects or dangers involved in the employment of this technology. The infrared imager currently being employed in this set of tests makes use of a Raytheon 320 X 240 Focal Plane Array (FPA) with an uncooled Barium Strontium Titanate (BST) detector. This is the least expensive of the three systems available to hospitals and surgeons interested in exploring the use of infrared imaging in open heart surgery. The second system that will be tested, will also be a 320 X 240 focal plane array but it will use a camera with an uncooled, microbolometer detector. This detector senses energy in approximately the 8 - 14 micron range. This system is capable of higher spatial resolution.
The most powerful system in this series, uses a sterling cycle, cooled, Indium Antimonide FPA with a 320 X 256 pixel array. This camera is a short wave camera, detecting infrared energy in the 3 - 5 micron bandwidth.

Summary:
Infrared imaging can play an important role in open heart surgery by supplying the surgeon with real time information that can assist in the ongoing decision making process that takes place during the procedure. The information supplied by the infrared camera is unavailable pre-operatively.

Ocular surface temperature gradient is increased in eyes with bacterial corneal ulcers.

Ocular surface temperature gradient is increased in eyes with bacterial corneal ulcers.

Klamann MK, Maier AK, Gonnermann J, Klein JP, Bertelmann E, Pleyer U.

Source

Department of Ophthalmology, Charité-University Medicine Berlin, Berlin, Germany. matthias.klamann@charite.de

Abstract

AIMS:

To investigate the ocular surface temperature gradient in eyes with bacterial corneal ulcers.

METHODS:

Prospective examination of 12 eyes with bacterial corneal ulcers (group 1) and 12 control eyes (group 2). Infrared thermal imaging (Tomey TG 1000) was used to study the temperature of the ocular surface. The mean, minimum and maximum temperature of the ocular surface and temperature course over a time period of 10 s of sustained eye opening were evaluated. Furthermore, a correlation between the overall corneal temperature and the temperature at the base of the corneal ulcers was determined.

RESULTS:

A significant difference between both groups was present. Mean corneal temperature was 35.6°C ± 0.9 in group 1 and 34.8°C ± 0.8 in group 2 (p = 0.033). The temperature course over 10 s of sustained eye opening was -0.6°C ± 0.4 in group 1 and -0.3°C ± 0.2 in group 2 (p = 0.045). There was a close correlation between the mean temperature at the base of the corneal ulcer and the overall corneal temperature (r = 0.92, p < 0.001).

CONCLUSION:

Infrared thermal imaging can be used to objectively determine the increased ocular surface temperature in patients with bacterial corneal ulcers. The use of dynamic thermography may offer new options to monitor ocular surface alterations.

Copyright © 2012 S. Karger AG, Basel.

CRPS and Neuropathic pain

THE ROLE OF INFRARED THERMAL IMAGING (ITI)

IN MANAGEMENT OF NEUROPATHIC PAIN

Hooshang Hooshmand, M.D. , Masood Hashmi, M.D. , and Eric M. Phillips

Neurological Associates Pain Management Center

1255 37th Street, Suite B

Vero Beach, Florida, USA.

 Abstract

The value of Infrared thermal imaging (ITI) is limited to evaluation of neurovascular dysfunction. It provides useful diagnostic and therapeutic information in the management of neuropathic pain[1].

Key Words: Infrared thermal imaging, neuropathic pain, ITI in pain management.

Introduction

The nociceptive chronic pain is usually due to involvement of large somesthetic (somatic) nerve fibres. Electromyography (EMG) and nerve conduction velocity (NCV) tests are usually the diagnostic tools for the study of somesthetic pain. In contrast, these tests are normal in neuropathic pain because they cannot detect changes in the microscopic thermosensory neurovasculature. The diagnosis and management of neuropathic pain requires neurovascular autonomic tests such as infrared thermal imaging.

Methods

The role of ITI in pain management was studied in 762 successive complex pain patients evaluated with ITI. The results were compared with a meta analysis of medical literature. A Bales Scientific Infrared Thermal Processor and an Agema (Flir) Infrared Thermal Processor were utilized in this study. The patients were cooled down in a 20-21ºC steady state room for 30 minutes of equilibration without clothing. No prior smoking for 90 minutes. A standard sensitivity of 24-34ºC was done. If the areas were not properly visualized the physician would adjust the sensitivity accordingly. Two identically reproducible images recorded on laser disc were required.

Results

The study revealed the importance of proper technique and proper clinical correlation. ITI is useful in the study of complex neuropathic pain. It provides indispensable diagnostic and therapeutic information. Both superficial and deep temperature changes influence the ITI test. The skin is an almost perfect radiator of both deep and surface heat. This radiator, has 98% emissive efficiency [2]. The ITI records pathological temperatures at least as deep as 27 mm (Fig 1) in the extremities, and even deeper in the breast [3-5].

Conclusion

ITI exclusively provides diagnostic information in neuropathic pain. Such information cannot be achieved by EMG or NCV. ITI is useless in diagnosis and management of cervical and lumbar sprain. It can spare patients from unnecessary amputation, carpal tunnel, temporomandibular joint, spinal disc surgeries and migraine. It is helpful in differentiating cervicogenic headache from migraine-each requiring opposite forms of treatment. In electrical injury ITI identifies points of entrance and exit of electricity. This picture is pathognomonic and is exclusively seen in electrical injury. ITI identifies hyperthermic foci of permanent sympathetic system damage sparing the patient from further damage by trauma of sympathetic nerve blocks.

References

1. Hooshmand H: Is thermal imaging of any use in pain management? Pain Digest. 1998; 8:166-170.

2.Elam R, Goodwin DN, Lloyd-Williams K: Optical properties of human epidermis. Nature [Lond]. 1963; 198:1001.

3. Lawson RN: Thermography- a new tool for the investigation of breast lesions. Can Med Assoc J. 1957; 13:517- 524.

4.Thermography and its clinical applications. Annals of the New York Academy of Science. 1964; 121: 304.

5. Ring EFJ: Progress in the measurement of human body temperature. IEEE Engineering in Medicine and Biology . July/August 1998; pp19-24.

Clinical Application Of Thermography In Dentistry

Clinical Application Of Thermography In Dentistry

Thermography measurement in the clinical set up can be done on a given spot or over an extended area of interest. Infrared telethermography of the face in normal subjects have shown that men have higher temperatures than females. The rationale behind this is that men have more basal metabolic than women and his skin dissipates more heat per unit area of body surface. Similarly age and ethnicity variations in facial temperature can also occur. [14-16]

In Chronic Orofacial pain patients

Gratt and his colleagues in 1996 developed a classification system using telethermographs for patients with chronic pain. [17] They classified them as normal when selected anatomic area (∆T) values range from 0.0 to +0.250C, hot when it is >0.350C, and cold when it is <0.350C. When a selected anatomic area value is 0.26- 0.350C, the finding is classified as equivocal. Moreover they also found that hot thermographs had the clinical diagnosis of (1) sympathetically maintained pain, (2) peripheral nerve mediated pain, (3) TMJ arthropathy, or (4) maxillary sinusitis. Subjects classified with cold subareas on their thermographs were found to have the clinical diagnosis of (1) peripheral nerve-mediated pain (2) sympathetically independent pain. Subjects classified with normal telethermographs included patients with the clinicaldiagnosis of (1) cracked tooth syndrome (2) trigeminal neuralgia (3) pretrigeminal neuralgia (4) psychogenic facial pain. This system of thermal classification resulted in 92% agreement in classifying pain patients making it as an important diagnostic parameter. [12,17]

In TMJ disorders

Normal TMJ examination using thermography had showed symmetrical thermal patterns with a mean

∆T values of 0.10C. [12, 14, 18] On the other hand, patients affected with internal derangement and TMJ osteoarthritis showed ∆T values of +0.40C. [19, 20] Beth and Gratt in 1996 conducted a double-blinded clinical study to compare the ∆T values among active orthodontic patients, TMD patients and symptomatic TMJ controls. The results showed that the average TMJ area ∆T values as +0.20C, +0.40C, and +0.10C in these groups respectively.(21) The above findings suggest that tele-thermography can distinguish between patients undergoing active orthodontic treatment and patients with TMD. [12,21]

In quantification of thermal insult to pulp

Dental pulpal tissue is exposed to variety of thermal insult during various dental treatment modalities.

Of late for debonding of orthodontic brackets Eelectro Thermal Ddebonding (ETD) method is widely used, this technique although has many advantages than the conventional mechanical method can pose serious thermal damage to pulp. Cummings and his colleagues in 1999 performed an in-vitro study on extracted human premolar teeth applying ETD. Thermal imaging analysis was done using mercury cadmium terullide detector showed that the pulpal temperature increased from 16.80C- 45.60C, which can pose serious threat to pulpal vitality. It can be stated from the study that, ETD methods needs intermittent cooling of the teeth with simultaneous thermal imaging to prevent pulpal damage. [22] Similarly the use of ultra high speed air-driven instrumentation during cavity preparation can result in serious thermal insult to the pulp. To overcome this, it is believed that various coolants (air water spray or air/water alone) can be used to reduce the intrapulpal temperature and prevent subsequent damage to the pulp. It was only until 1979, when Carson and his colleagues performed a study employing thermography to determine the pattern of heat distribution and dissipation during ultra-speed cavity preparation using both an air-water spray and air only coolants to determine if a point heat source is generated. This study stated that the mean magnitude of temperature increases with both types of coolant, 2.80C and 3.670C, probably does not exceed the physiologic limits of the pulp. [23] 

In assessing inferior alveolar nerve deficit

Over the years numerous studies have shown that thermal imaging technique can play a vital role in effective assessment of inferior alveolar nerve deficit. [12,24] Gratt and his colleagues in 1994 stated that patients with inferior alveolar nerve deficit when examined showed ∆T values of +0.50C on the affected side whereas subjects with no inferior alveolar nerve deficit showed a symmetrical thermal ∆T value of +0.10C. [25] The authors stated that the changes are due to blockage of the vascular neuronal vasoconstriction and this was confirmed by the same colleagues in the same year when similar thermological picture was obtained in normal subjects by temporary blockage of the inferior alveolar nerve using 2% lidocaine. [26]

Qualitative evaluation of N2O concentration

N2O is a highly insoluble gas which is rapidly absorbed and is eliminated swiftly by the lungs, thus it is used widely either alone or in combination with other anesthetic agents. [27] Results of various studies have shown that leakage of N2O into the workplace can lead to adverse health effects such as reproductive, hematologic and nervous dysfunctions. [28] Studies on acute and chronic occupational exposures have shown that N2O air concentration levels as low as 50 parts per million (ppm) can result in bone marrow depression, paresthesias, altered concentration, impaired visual effects, alterations in vitamin B12 and plasma homocysteine concentrations. [29-31]

In response to these findings and in order to effectively control exposures several guidelines have been published that define appropriate use and control criteria for N2O usage. The ADA made 10 recommendations that address the use of appropriate engineering controls for proper scavenging. [32] However, they are proved futile and health hazards secondary to N2O exposure is still on the rise. Rademaker et al in 2009 conducted a study using infrared thermography to determine the effectiveness of two N2O scavenging systems- The Safe Sedate Dental Mask (Airgas, Radnor, Pa.) system (System I) and Porter Nitrous Oxide Sedation System (Porter Instrument, Hatfield, Pa.) (System II). The results suggested that neither of the system was able to control occupational exposure of N2O oxide below the NIOSH REL. [33]

Additional applications of telethermography

- Evaluation of cranio mandibular disorders. [34]

- Detection of carotid occlusal disease. [35]

- Quantification of the effects of post-surgical inflammation. [36]

- Quantification of the effects of analgesics, anti-inflammatory drugs, etc.

- In the diagnosis of myofacial symptoms.

Conclusion

Thermography aids in the assessment and staging of various dysfunctions of the head and neck region.The unique significance of thermography is both qualitative and quantitative assessment which helps in estimation of progression of the disease in a systematic manner. With the innovation of novel equipments and the state of the art facility, thermography in the near future will certainly re-emerge as a unique research tool in dentistry.

References

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[19] Gratt BM, Sickles EA, Ross JB. Thermographic characterization of an intemal derangement of the temporomandibular joint. J Orofacial Pain. 1994; 8: 197-206.

[20] Gratt BM, Sickles EA, Wexler CA. Thermographic characterization of osteoarthrosis of the temporomandibular joint. J Orofacial Pain. 1993; 7: 345-353.

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[22] Cummings M, Biagioni P, Lamey PJ, Burden DJ. Thermal image analysis of electrothermal debonding of ceramic brackets: an in vitro study. European Journal of Orthodontics. 1991; 21: 111-118.

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