Wednesday, January 28, 2015
Tuesday, January 20, 2015
Heat transfer model for deep tissue injury: a step towards an early thermographic diagnostic capability
Heat transfer model for deep tissue injury: a step towards an early thermographic diagnostic capability
Abstract
Background
Deep tissue injury (DTI) is a class of serious lesions which develop
in the deep tissue layers as a result of sustained tissue loading or
pressure-induced ischemic injury. DTI lesions often do not become visible on
the skin surface until the injury reaches an advanced stage, making their early
detection a challenging task.
Theory
Early diagnosis leading to early treatment mitigates the progression
of the lesion and remains one of the priorities in clinical care. The aim of
the study is to relate changes in tissue temperature with key physiological
changes occurring at the tissue level to develop criteria for the detection of
incipient DTIs.
Method
Skin surface temperature distributions of the damaged tissue were
analyzed using a multilayer tissue model. Thermal response of the skin surface
to a cooling stress, was computed for deep tissue inflammation and deep tissue
ischemia, and then compared with computed skin temperature of healthy tissue.
Results
For a deep lesion situated in muscle and fat layers, measurable skin
temperature differences were observed within the first five minutes of thermal
recovery period including temperature increases between 0.25°C to 0.9°C during
inflammation and temperature decreases between −0.2°C to −0.5°C during
ischemia.
Conclusions
The computational thermal models can explain previously published
thermographic findings related to DTIs and pressure ulcers. It is concluded
that infrared thermography can be used as an objective, non-invasive and
quantitative means of early DTI diagnosis.
Medical Infrared Imaging
Skin temperature measured by infrared thermography
after ultrasound-guided blockade of the sciatic nerve.
Abstract
BACKGROUND:
In the present study, we assessed
the relationship between subgluteal sciatic nerve blocking and skin temperature
by infrared thermography in the lower extremity. We hypothesized that blocking
the sciatic nerve will lead to an increase in temperature, and that this will
correlate with existing sensory block tests.
METHODS:
We studied 18 healthy individuals
undergoing orthopaedic surgery of the foot under ultrasound-guided subgluteal
blockade of the sciatic nerve with 30 ml ropivacaine 7.5 mg/ml. Skin
temperature was measured on the toes, the dorsal and plantar side of the foot,
the malleoli, and the lateral side of the lower leg, just before sciatic nerve
blockade and at 10-min intervals thereafter.
RESULTS:
Baseline skin temperatures showed a
significant distal-to-proximal gradient. After sciatic block, temperatures on
the blocked side increased significantly in the toes and foot. When comparing
pinprick to skin temperature in a receiver operating curve, there was an AUC of
85.9% (95% confidence interval = 83.7-88.2%, P < 0.001). The medial
malleolus (not being innervated by the sciatic nerve) showed no significant
difference to the lateral.
CONCLUSIONS:
After sciatic nerve block,
temperatures of the foot increased significantly. There was a good correlation
between pinprick testing and infrared temperature measurement. This makes
infrared skin temperature measuring a good test in determining block success
when sensory testing is impossible.
© 2013 The Acta Anaesthesiologica
Scandinavica Foundation. Published by John Wiley & Sons Ltd.
Medical Infrared Imaging
Does the temperature
gradient correlate with the photodynamic diagnosis parameter numerical colour
value (NCV)?
Source
Institute of Physics, Department of Medical Physics, University of Silesia, Uniwersytecka 4,
40-007 Katowice, Poland. armand.cholewka@gmail.com
Abstract
BACKGROUND:
Photodynamic diagnosis
(PDD) as well as thermovision belong to the category of non-invasive optical
diagnosis techniques. Among many different skin cancer diseases, basal cell
carcinoma (BCC) is the most frequently occurring one (almost 95% of all skin
tumours). In contrast, seborrhoeic keratosis represents almost 70% of benign
skin tumours. In this paper we present infrared thermography as an additional method, combined with PDD, to
show the differentiation between these two skin mutations.
METHODS:
The photodynamic
diagnosis studies were performed by using the autofluorescence diagnosis system
Xillix Onco. As an additional non-invasive diagnosis technique, thermovision
studies were performed. Thermal imaging was done by using a Thermovision Camera
A40M with a sensitivity of 0.07K. The thermograms of the chosen areas were
performed in a special room with a temperature of 22.5±1°C. All patients were
treated in the Chair and Clinic of Internal Diseases, Angiology and Physical
Medicine in Bytom. Thirteen skin lesions were studied: 9 diagnosed as basal
cell carcinoma and 4 as seborrhoeic keratosis. All skin lesions were confirmed
in histopathological examinations.
RESULTS
AND CONCLUSIONS:
The results of the
studies revealed significant differences in skin thermal mapping between
patients suffering from basal cell carcinoma and seborrhoeic keratosis. It
appears that benign skin lesions are characterised by a lower mean temperature
than the surrounding healthy skin. To the contrary, cancerous skin mutations
appeared on the thermal map at a higher mean temperature. Thermal images for
the chosen skin lesions and temperature parameters derived from the thermograms
are contiguous with the photodynamic diagnosis results and may give some
additional diagnostic information.
Wednesday, August 20, 2014
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 (ΔT) 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 ΔT values of 0.10C. [12, 14, 18] On the other hand, patients affected with internal derangement and TMJ osteoarthritis showed ΔT values of +0.40C. [19, 20] Beth and Gratt in 1996 conducted a double-blinded clinical study to compare the ΔT values among active orthodontic patients, TMD patients and symptomatic TMJ controls. The results showed that the average TMJ area ΔT 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 ΔT values of +0.50C on the affected side whereas subjects with no inferior alveolar nerve deficit showed a symmetrical thermal ΔT 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
[1] Anbar M. Diagnostic thermal imaging: A historical technological perspective. In: Anbar M (ed). Quantitative Dynamic Telethermography in Medical Diagnosis. CRC Press: BocaRaton. 1994), pp 1-9.
[2] Adams F. Hippocratic Writings, In: Hutchins RM (ed). (Hippocrates, Galen, Vol. 10 of Great Books of the Western World, Univ. of Chicago, Encyclopedia Britannica Inc. 1952),pp 66-77.
[3] Wolf A. A History of Science and Technology and Philosophy in the 16th & 17th Centuries. 2nd ed., McKee D (ed). George Allen & Unwin: London. 1950, pp 66-77.
[4] Bedford RE. Thermometry. In: The New Encyclopedia Britannica, 15th ed, Chicago. Ill. 1992; 11: 702-703.
[5] Hardy JD. The radiation of heat from the human body: I-IV. J Clin Invest. 1934; 13: 593-620.
[6] Hardy JD, Muschenheim C. The radiation of heat from the human body: V. J Clin Invest. 1936; 15: 1-8.
[7] Weinstein SA. Standards for neuromuscular thermographic examination. Modern Medicine: supplement. 1986; 1: 5-7.
[8] Anbar M, Gratt BM, Hong D. Thermology and facial telethermography. Part I: history and technical review. Dento maxillofac Radiol. 1998; 27: 61-67.
[9] Anbar M. Fundamentals of computerized thermal imaging. In: Anbar M. Quantitative Dynamic Telethermography in Medical Diagnosis. CRC Press: Boca Raton. 1994, pp 99-131.
[10] Anbar M. Dynamic area telethermometry: a new field in clinical thermology: Part II. Medical Electronics. 1994; 147: 73-85.
[11] Anbar M. Dynamic area telethermometry and its clinical applications. SPIE Proc. 1995; 2473: 312-331
[12] Gratt BM, Anbar M. Thermology and facial telethermography: Part II: Current and future clinical applications in dentistry. Dento maxillofac Radiol. 1998; 27: 68-74.
[13] Ongole R, Praveen BN. Chapter 21- Specialized imaging techniques. In: Clinical manual for Oral Medicine and Radiology. Jaypee Brothers, New Delhi. 2007, pp 439-441.
[14] Gratt BM, Sickles EA. Electronic facial thermography: an analysis of asymptomatic adult subjects. J Orofacial Pain. 1995; 9: 255-265.
[15] Blaxter K. Energy exchange by radiation, convection, conduction, and evaporation. In: Energy Metabolism in Animals and Man Cambridge Univ. Press: New York, 1989: pp 86- 99.
[16] Blaxter K. The minimal metabolism. In: Energy Metabolism in Animals and Man. Cambridge Univ. Press: New York, 1989, pp 120-146.
[17] Gratt BM, Graff-Radford SB, Shetty V, Solberg WK, Sickles EA. A six-year clinical assessment of electronic facial thermography Dentomaxillofac Radiol. 1996; 25: 247 -255.
[18] Gratt BM, Sickles EA. Thermographic characterization of the asymptomatic TMJ. J Orofacial Pain. 1993; 7: 7-14.
[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.
[21] McBeth SA, Gratt BM. A cross-sectional thermographic assessment of TMJ problems in orthodontic patients. Am J Orthod Dentofac Orthop. 1996; 109: 481-488.
[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.
[23] Carson J, Rider T, Nash D. A Thermographic Study of Heat Distribution during Ultra-Speed Cavity preparation. J Dent Res. 1979; 58; 16-81.
[24] Gratt BM, Shetty V, Saiar M, Sickles EA. Electronic thermography for the assessment of inferior alveolar nerve deficit. Oral Surg Oral Med Oral Pathol. 1995; 80: 153-160.
[25] Gratt BM, Sickles EA, Shetty V. Thermography for the clinical assessment of inferior alveolar nerve deficit: A pilot study. J Orofacial Pain. 1994; 8: 369- 374.
[26] Shetty V, Gratt BM, Flack V. Thermographic assessment of reversible inferior alveolar nerve deficit. J Orofacial Pain. 1994; 8: 375-383.
[27] Emmanouil DE, Quock RM. Advances in understanding the actions of nitrous oxide. Anesth Prog. 2007; 54(1):9-18.
[28] Cohen EN, Brown BW Jr, Bruce DL, et al. A survey of anesthetic health hazards among dentists. JADA. 1975; 90(6):1291-1296.
[29] McGlothlin JD, Crouch KG, Mickelsen RL. Control of nitrous oxide in dental operatories. Cincinnati: National Institute for Occupational Safety and Health; U.S. Department of Health and Human Services (NIOSH) publication.1994; 94-129.
[30] Krajewski W, Kucharska M, Pilacik B, et al. Impaired vitamin B12 metabolic status in healthcare workers occupationally exposed to nitrous oxide. Br J Anaesth. 2007;99(6):812-818.
[31] Myles PS, Chan MT, Leslie K, Peyton P, Paech M, Forbes A. Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery. Br J Anaesth. 2008; 100(6):780-786.
[32] ADA Council on Scientific Affairs; ADA Council on Dental Practice. Nitrous oxide in the dental office. JADA. 1997; 128(3):364-365.
[33] Rademaker MA et al. Evaluation of Two Nitrous Oxide Scavenging systems Using Infrared Thermography to Visualize and Control Emissions. J Am Dent Assoc. 2009; 140; 190-199.
[34] Biagioni PA, Longmore RB, McGimpsey JG, Lamey PJ. Infrared thermography. Its role in dental research with particular reference to craniomandibular disorders. Dentomaxillofac Radiol. 1996; 25: 119-124.
[35] Friedlander AH, Gratt BM. Panoramic dental radiography and thermography as an aid in detecting patients at risk for stroke. J Oral Maxillofac Surg. 1994; 52: 1257- 1262.
[36] Sudhakar S, Bina kayshap, Sridhar reddy P. Thermography in dentistry-revisited. Int J Biol Med Res. 2011; 2(1): 461-465
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 (ΔT) 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 ΔT values of 0.10C. [12, 14, 18] On the other hand, patients affected with internal derangement and TMJ osteoarthritis showed ΔT values of +0.40C. [19, 20] Beth and Gratt in 1996 conducted a double-blinded clinical study to compare the ΔT values among active orthodontic patients, TMD patients and symptomatic TMJ controls. The results showed that the average TMJ area ΔT 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 ΔT values of +0.50C on the affected side whereas subjects with no inferior alveolar nerve deficit showed a symmetrical thermal ΔT 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
[1] Anbar M. Diagnostic thermal imaging: A historical technological perspective. In: Anbar M (ed). Quantitative Dynamic Telethermography in Medical Diagnosis. CRC Press: BocaRaton. 1994), pp 1-9.
[2] Adams F. Hippocratic Writings, In: Hutchins RM (ed). (Hippocrates, Galen, Vol. 10 of Great Books of the Western World, Univ. of Chicago, Encyclopedia Britannica Inc. 1952),pp 66-77.
[3] Wolf A. A History of Science and Technology and Philosophy in the 16th & 17th Centuries. 2nd ed., McKee D (ed). George Allen & Unwin: London. 1950, pp 66-77.
[4] Bedford RE. Thermometry. In: The New Encyclopedia Britannica, 15th ed, Chicago. Ill. 1992; 11: 702-703.
[5] Hardy JD. The radiation of heat from the human body: I-IV. J Clin Invest. 1934; 13: 593-620.
[6] Hardy JD, Muschenheim C. The radiation of heat from the human body: V. J Clin Invest. 1936; 15: 1-8.
[7] Weinstein SA. Standards for neuromuscular thermographic examination. Modern Medicine: supplement. 1986; 1: 5-7.
[8] Anbar M, Gratt BM, Hong D. Thermology and facial telethermography. Part I: history and technical review. Dento maxillofac Radiol. 1998; 27: 61-67.
[9] Anbar M. Fundamentals of computerized thermal imaging. In: Anbar M. Quantitative Dynamic Telethermography in Medical Diagnosis. CRC Press: Boca Raton. 1994, pp 99-131.
[10] Anbar M. Dynamic area telethermometry: a new field in clinical thermology: Part II. Medical Electronics. 1994; 147: 73-85.
[11] Anbar M. Dynamic area telethermometry and its clinical applications. SPIE Proc. 1995; 2473: 312-331
[12] Gratt BM, Anbar M. Thermology and facial telethermography: Part II: Current and future clinical applications in dentistry. Dento maxillofac Radiol. 1998; 27: 68-74.
[13] Ongole R, Praveen BN. Chapter 21- Specialized imaging techniques. In: Clinical manual for Oral Medicine and Radiology. Jaypee Brothers, New Delhi. 2007, pp 439-441.
[14] Gratt BM, Sickles EA. Electronic facial thermography: an analysis of asymptomatic adult subjects. J Orofacial Pain. 1995; 9: 255-265.
[15] Blaxter K. Energy exchange by radiation, convection, conduction, and evaporation. In: Energy Metabolism in Animals and Man Cambridge Univ. Press: New York, 1989: pp 86- 99.
[16] Blaxter K. The minimal metabolism. In: Energy Metabolism in Animals and Man. Cambridge Univ. Press: New York, 1989, pp 120-146.
[17] Gratt BM, Graff-Radford SB, Shetty V, Solberg WK, Sickles EA. A six-year clinical assessment of electronic facial thermography Dentomaxillofac Radiol. 1996; 25: 247 -255.
[18] Gratt BM, Sickles EA. Thermographic characterization of the asymptomatic TMJ. J Orofacial Pain. 1993; 7: 7-14.
[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.
[21] McBeth SA, Gratt BM. A cross-sectional thermographic assessment of TMJ problems in orthodontic patients. Am J Orthod Dentofac Orthop. 1996; 109: 481-488.
[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.
[23] Carson J, Rider T, Nash D. A Thermographic Study of Heat Distribution during Ultra-Speed Cavity preparation. J Dent Res. 1979; 58; 16-81.
[24] Gratt BM, Shetty V, Saiar M, Sickles EA. Electronic thermography for the assessment of inferior alveolar nerve deficit. Oral Surg Oral Med Oral Pathol. 1995; 80: 153-160.
[25] Gratt BM, Sickles EA, Shetty V. Thermography for the clinical assessment of inferior alveolar nerve deficit: A pilot study. J Orofacial Pain. 1994; 8: 369- 374.
[26] Shetty V, Gratt BM, Flack V. Thermographic assessment of reversible inferior alveolar nerve deficit. J Orofacial Pain. 1994; 8: 375-383.
[27] Emmanouil DE, Quock RM. Advances in understanding the actions of nitrous oxide. Anesth Prog. 2007; 54(1):9-18.
[28] Cohen EN, Brown BW Jr, Bruce DL, et al. A survey of anesthetic health hazards among dentists. JADA. 1975; 90(6):1291-1296.
[29] McGlothlin JD, Crouch KG, Mickelsen RL. Control of nitrous oxide in dental operatories. Cincinnati: National Institute for Occupational Safety and Health; U.S. Department of Health and Human Services (NIOSH) publication.1994; 94-129.
[30] Krajewski W, Kucharska M, Pilacik B, et al. Impaired vitamin B12 metabolic status in healthcare workers occupationally exposed to nitrous oxide. Br J Anaesth. 2007;99(6):812-818.
[31] Myles PS, Chan MT, Leslie K, Peyton P, Paech M, Forbes A. Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery. Br J Anaesth. 2008; 100(6):780-786.
[32] ADA Council on Scientific Affairs; ADA Council on Dental Practice. Nitrous oxide in the dental office. JADA. 1997; 128(3):364-365.
[33] Rademaker MA et al. Evaluation of Two Nitrous Oxide Scavenging systems Using Infrared Thermography to Visualize and Control Emissions. J Am Dent Assoc. 2009; 140; 190-199.
[34] Biagioni PA, Longmore RB, McGimpsey JG, Lamey PJ. Infrared thermography. Its role in dental research with particular reference to craniomandibular disorders. Dentomaxillofac Radiol. 1996; 25: 119-124.
[35] Friedlander AH, Gratt BM. Panoramic dental radiography and thermography as an aid in detecting patients at risk for stroke. J Oral Maxillofac Surg. 1994; 52: 1257- 1262.
[36] Sudhakar S, Bina kayshap, Sridhar reddy P. Thermography in dentistry-revisited. Int J Biol Med Res. 2011; 2(1): 461-465
Tuesday, August 19, 2014
Infrared thermography: Experience from a decade of pediatric imaging.
Eur J Pediatr. 2007 Aug 30;
Infrared thermography: Experience from a decade of pediatric imaging.
Saxena AK, Willital GH.
Department of Pediatric Surgery, Medical University of Graz, Auenbruggerplatz 34, Graz, A-8036, Austria
The aim of this study was to evaluate the feasibility of clinical application of infrared thermography (IRT) in the pediatric population and to identify pathological states that can be diagnosed as well as followed up using this non-invasive technique. In real time computer-assisted IRT, 483 examinations were performed over a period of 10 years from 1990-2000 on 285 patients in the pediatric age group (range 1 week-16 years) presenting with a wide range of pathologies. The temperature was measured in centigrade (degrees C), and color images obtained were computer analyzed and stored on floppy discs. IRT was found to be an excellent noninvasive tool in the follow-up of hemangiomas, vascular
malformations and digit amputations related to reimplantation, burns as well as skin and vascular
growth after biomaterial implants in newborns with gastroschisis and giant omphaloceles. In the
emergency room, it was a valuable tool for rapid diagnosis of extremity thrombosis, varicoceles,
inflammation, abscesses, gangrene and wound infections. In conclusion, IRT can be performed in
the pediatric age group, is non-invasive, without any biological side effects, requires no sedation or
anesthesia and can be repeated as desired for follow-ups, with objective results that can demonstrated as colored images. Periodic thermographic studies to follow progression of lesions seem to be a
useful and reproducible method.
Infrared thermography: Experience from a decade of pediatric imaging.
Saxena AK, Willital GH.
Department of Pediatric Surgery, Medical University of Graz, Auenbruggerplatz 34, Graz, A-8036, Austria
The aim of this study was to evaluate the feasibility of clinical application of infrared thermography (IRT) in the pediatric population and to identify pathological states that can be diagnosed as well as followed up using this non-invasive technique. In real time computer-assisted IRT, 483 examinations were performed over a period of 10 years from 1990-2000 on 285 patients in the pediatric age group (range 1 week-16 years) presenting with a wide range of pathologies. The temperature was measured in centigrade (degrees C), and color images obtained were computer analyzed and stored on floppy discs. IRT was found to be an excellent noninvasive tool in the follow-up of hemangiomas, vascular
malformations and digit amputations related to reimplantation, burns as well as skin and vascular
growth after biomaterial implants in newborns with gastroschisis and giant omphaloceles. In the
emergency room, it was a valuable tool for rapid diagnosis of extremity thrombosis, varicoceles,
inflammation, abscesses, gangrene and wound infections. In conclusion, IRT can be performed in
the pediatric age group, is non-invasive, without any biological side effects, requires no sedation or
anesthesia and can be repeated as desired for follow-ups, with objective results that can demonstrated as colored images. Periodic thermographic studies to follow progression of lesions seem to be a
useful and reproducible method.
Wednesday, May 15, 2013
Polygraph
Periorbital thermal signal extraction and applications.
Shastri D, Tsiamyrtzis P, Pavlidis I. Computational Physiology Lab, University of Houston, Houston, TX
We propose a novel method that localizes the thermal footprint of the facial and ophthalmic arterial-venous complexes in the periorbital area. This footprint is used to extract the mean thermal signal over time (periorbital signal), which is a correlate of the blood supply to the ocular muscle. Previous work demonstrated that the periorbital signal is associated to autonomic responses and it changes significantly upon the onset of instantaneous stress. The present method enables accurate and consistent extraction of this signal. It aims to replace the heuristic segmentation approach that has been used in stress quantification thus far. Applications in computational psychology and particularly in deception detection are the first to benefit from this new technology. We tested the method on thermal videos of 39 subjects who faced stressful interrogation for a mock crime. The results show that the proposed approach has improved the deception classification success rate to 82%, which is 20% higher compared to the previous approach.
Thursday, May 9, 2013
Facial thermography is a sensitive and specific method for assessing food challenge outcome.
Clark AT, Mangat JS, Tay SS, King Y, Monk CJ, White PA, Ewan PW. Department of Allergy, Cambridge University Hospitals NHS Trust, Addenbrookes Hospital, Cambridge, UK.
BACKGROUND: Oral challenge is widely used for diagnosing food allergy but variable interpretation of
subjective symptoms may cause error. Facial thermography was evaluated as a novel, objective and
sensitive indicator of challenge outcome.
METHODS: A total of 24 children with a history of egg allergy underwent oral challenge, which were scored positive when objective symptoms occurred or negative after all doses were consumed without reaction. Facial temperatures were recorded at baseline and 10-min intervals. The difference between mean and baseline temperature (DeltaT), maximum DeltaT during challenge (DeltaT(max)) and area under curve of DeltaT against time (DeltaTAUC) were calculated for predefined nasal, oral and forehead areas, and related to objective challenge outcome.
RESULTS: There were 13 positive and 11 negative challenges. Median nasal DeltaTAUC and DeltaT(max) were greater in positive compared with negative challenges (231- and 5-fold, respectively; P < 0.05). In positive challenges, nasal temperatures showed an early transient rise at 20 min, preceding objective symptoms at median 67 min. There was a sustained temperature increase from 60 min, which was reduced by antihistamines. A cut-off for nasal DeltaT(max) of 0.8 degrees C occurring within 20 min of the start of the challenge predicted outcome with 91% sensitivity (positive predictive value [PPV] 100%) and 100%
specificity (negative predictive value [NPV] 93%). Subjective symptoms occurred in four of 13 positive and
three of 11 negative challenges.
CONCLUSIONS: Facial thermography consistently detects a significant early rise in nasal temperature during positive compared with negative food challenges, which is evident before objective symptoms occur.
Thermography may therefore provide a sensitive method to determine outcome of food challenges and investigate the pathophysiology of food allergic reactions.
Monday, May 6, 2013
Intraoperative application of thermography in extracranial-intracranial bypass surgery.
Okada Y, Kawamata T, Kawashima A, Hori T Department of Neurosurgery, Tokyo Women's Medical University, Tokyo, Japan. yokada@nij.twmu.ac.jp
OBJECTIVE: The extracranial-intracranial bypass may have the potential to improve hemodynamic cerebral ischemia caused by occlusive diseases of the main cerebral arteries. Intraoperative confirmation of effective distribution of blood flow via the donor arteries to the involved region will assure a successful bypass surgery.
METHODS: Infrared thermography was used to measure the temperature of the cortical surface at the operative field. Regional cerebral blood flow (rCBF) was measured with a laser Doppler flow meter. Changes in the cortical surface temperature before and after temporary occlusion of the bypass were compared with changes in rCBF values in the corresponding sites.
RESULTS: Thermographic examination demonstrated a heterogeneous increase of cortical surface temperature caused by the blood flow via the extracranial-intracranial bypass and was closely related to rCBF changes.
CONCLUSION: Thermography is useful not only to demonstrate the distribution of blood flow through the extracranial-intracranial bypass but also to quantitatively evaluate the rCBF changes in the operative field.
Neurophysiological study of thin myelinated and unmyelinated fibers.
Espinosa ML, Santiago S, Guzman JJ, Prieto J, Ferrer T; Laboratorio de SNA, Hospital General
La Paz, Madrid, Espana.
INTRODUCTION: Standard neurophysiological techniques evaluate thick myelinated fibers. Yet,
peripheral nerves are equally composed of thin myelinated and unmyelinated fibers. The latter are
responsible for autonomic function as well as temperature and pain perception.
DEVELOPMENT:
Microneurographic studies are restricted to investigation laboratories. Since the techniques are complex
and invasive, their performance is still poor for clinical purposes and some of the components to be
analyzed, such as cardiovagal, cannot be directly recorded. The clinical need to evaluate the functions
regulated by the autonomic nervous system (ANS) had led to devising a series of tests which, in most
cases, rely on reflex responses evoked by already known standardize stimuli. The battery chosen has to
be non invasive, reproducible, specific, providing relevant data to the investigated function, with a readily
available technology, which has to be managed being aware of the physiological and pathological factors
that might bear an influence on the results. The recent development of heart rate blood pressure power
spectral analysis, provides a new interesting insight for quantification of ANS abnormalities. The study of
thermography and thermometry of body surface brings forward evidence on the activity of other thin and
unmyelinated fibers components of the peripheral nerve spectrum.
CONCLUSION: The adequate
management of the above mentioned tests gives rise to a more extensive and appropriate knowledge of
the whole peripheral nerve fiber spectrum.
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