Paste yINFRARED THERMAL IMAGING AND COLOUR DUPLEX ULTRASOUND ASSESSMENT OF PERIPHERAL ARTERIAL DISORDERS.
PROFORMA
FOR THE DEGREE OF
DOCTOR OF MEDICINE
RADIO-DIAGNOSIS
Shri Guru Ram Rai Institute of Medical & Health Sciences
Patel Nagar, Dehradun.
H.N.B. Garhwal University
Srinagar, Uttarakhand.
Dr Tarang Chauhan. (Batch 2018)
Shri Guru Ram Rai Institute of Medical & Health Sciences
Patel Nagar, Dehradun
H.N.B. Garhwal Medical University
Dehradun, Uttarakhand.
Dr. TARANG CHAUHAN
Pro-forma for the Registration of Thesis
For M.D. RADIO-DIAGNOSIS 2018
H.N.B. Garhwal, University
Name of Candidate : Dr. Tarang Chauhan
Department : Radio-diagnosis
Title of Thesis : INFRARED THERMAL IMAGING AND COLOUR DUPLEX ULTRASOUND ASSESSMENT OF PERIPHERAL ARTERIAL DISORDERS.
Introduction : (enclosed) page 7-9
Aims & Objectives : (enclosed) page 10
Material & Methods : (enclosed) page 11-15
Review of Literature : (enclosed) page 16-19
Bibliography : (enclosed) page 20-21
Supervisor : Dr. V.K SHARMA
Associate Professor
Department of Radio diagnosis
SGRRIM&HS
Dehradun.
Co-Supervisor : Dr. ROHIT SHARMA
Assistant Professor
Department of Radio diagnosis
SGRRIM&HS
Dehradun.
Place: Dehradun
Date: Signature of Candidate
RECOMMENDATION OF SUPERVISOR & CO-SUPERVISOR
The thesis titled “ INFRARED THERMAL IMAGING AND COLOUR DUPLEX ULTRASOUND ASSESSMENT OF PERIPHERAL ARTERIAL DISORDERS” of Dr. Tarang Chauhan for registration in MD (Radio-diagnosis) of HNB Garhwal Medical University, Dehradun, Uttarakhand is hereby recommended.
Supervisor : Dr. V.K SHARMA
Associate Professor
Department of Radio diagnosis
SGRRIM&HS
Dehradun.
SIGNATURE :
Co-Supervisor : Dr. ROHIT SHARMA
Assistant Professor
Department of Radio diagnosis
SGRRIM&HS
Dehradun.
SIGNATURE :
Certificate by Head of Department
The proforma for thesis titled “INFRARED THERMAL IMAGING AND COLOUR DUPLEX ULTRASOUND ASSESSMENT OF PERIPHERAL ARTERIAL DISORDERS’’ of Dr. Tarang Chauhan for registration in MD (Radio diagnosis) of HNB Garhwal University, Srinagar, Uttarakhand can be undertaken in the institute. All facilities will be provided to the candidate for the same. The work shall be done under regular monitoring of supervisor.
Name of HOD : Dr. Rajendra Kumar Srivastava
Designation : Professor and HOD
Department : Department of Radio diagnosis
Institute : Shri Guru Ram Rai Institute of Medical & Health
Sciences
Place : Dehradun
Date :
SIGNATURE :
Introduction
Peripheral artery disease is a condition associated with narrowing of the peripheral arteries in the legs, arms and head, most commonly affecting arteries of lower limbs. Lower extremity peripheral artery disease is the third leading cause of atherosclerotic cardiovascular morbidity, following coronary artery disease and stroke. [1]
Risk factors for peripheral arterial diseases include old age , male gender , dyslipidaemia ,hypertension , hyperhomocysteinemia , renal insufficiency, diabetes mellitus and smoking . Diabetes mellitus and smoking among them being the major risk factors. [2] Thromboangitis obliterans is one of the condition, leading to peripheral arterial disease affecting young males aged 20 – 40 years who are chronic smokers.
For long conventional angiography has been considered the gold standard in evaluation of peripheral artery disease and is done before any surgery is planned. This investigation is done to demonstrate the extent of the narrowing, condition of vessels above the narrowing, development of collaterals. It provides excellent anatomical detail. However, it does not give adequate physiological information about hemodynamics of lower limb. It is associated with risks due to its invasiveness, cost and contrast associated complications.
With the introduction of CT angiography, MR angiography, the study has become further improvised but because of their high cost, colour Doppler Duplex sonography becomes the most easily available modality for evaluation of arteries. Over the past several years, interest in non-invasive evaluation of peripheral artery disease has increased rapidly. The use of the Duplex sonography has revolutionized the non-invasive assessment of blood vessels. Colour Doppler is the most valuable of the non- invasive tests. It can provide most of the essential anatomic information and functional information like velocity gradients across the stenosis, degree and extent of occlusion. Doppler studies are also helpful in postoperative follow- up of operated limbs where arterial surgery has been carried out. In this study the peripheral arterial diseases will be evaluated by colour Doppler Duplex imaging and by thermography.
The correlation of body temperature and diseases has been known since ages. Infrared thermal imaging is a fast, passive, non-contact and non-invasive alternative to conventional clinical thermometers for monitoring body temperature. Besides infrared thermography can also map body surface temperature remotely. Czerny documented first infrared image of human subject in Frankfurt in 1928. [3] Initial medical application of infrared thermography was in preclinical diagnosis of breast cancer in the year 1956. [4] According to laws of physics all bodies with a temperature above absolute zero Kelvin ( – 273 .c) emit radiations (Planck’s law) and those with absolute temperature between 100 k and 3000k emit it in infrared spectrum ( Wien’s law). The above-stated fact which is valid for a black body is also valid for skin. [5]
Last five decades has witnessed a steady increase in the utility of thermal imaging cameras. Infrared thermal imaging has been successfully used in diagnosis of breast cancer, diabetic neuropathy and peripheral vascular disorders. It is also used to detect problems associated with gynaecology, dermatology, neonatal physiology. With modern infrared cameras, data acquisition and processing techniques, it is now possible to have real time high resolution thermal images, which is likely to surge further research in this field.[6] With infrared thermal imaging we can effectively screen the population at community level because image acquisition is easy and image interpretation can be done separately offering added advantage over Doppler studies which requires expertise and is more time consuming thus making it faster screening modality. Infrared thermal imaging is fast and non-contact technology capable of acquiring multiple images in short time intervals and absolutely safe for patients and doctors. [7] Newer imaging advances and applications are currently ongoing in the field of medical infrared thermal imaging.
To the best of my knowledge based on research on Pubmed and other internet sources , till now no study has been successful to conclude the role of infrared thermal imaging for screening of Peripheral arterial disease. Our study will help in comparing the diagnostic value of thermography with ultrasound Doppler findings.
Aims and objectives
– To find out potential use of infrared thermography in early detection and screening of peripheral arterial diseases.
– To evaluate the perfusion patterns of thermography and compare it with patterns of duplex sonography in hemodynamically significant peripheral arterial disease.
Materials and methods
1. Study area
The study will be conducted in Department of Radio-diagnosis Shri Guru Ram Rai Institute of Medical and Health Sciences Dehradun Patel Nagar after approval from research and ethical committee of the institute.
2. Study population
We will be doing a Study of diagnostic accuracy between two modalities i.e. infrared thermal imaging and USG Doppler comprising 50 patients/subjects coming to Radio diagnosis department of Shri Mahant Indrish hospital for arterial Doppler study.
3. Equipments
1. Thermo graphic examination will be performed by Mob IR – 8 camera with thermal sensitivity of 0.5-1 degree Celsius.
2. Doppler sonographic examination will be performed by various ultrasound machines in the department.
3. Inclusion Criteria
• Clinically suspected cases of peripheral arterial diseases.
• As a pre requisite before surgery in patients with peripheral arterial diseases.
6. Exclusion criteria
• Patients not ready to give consent for the study.
7. Methodology
This will be a study of diagnostic accuracy between the two modes of investigation comprising 50 patients.
Study planning
History of the patients will be recorded regarding age, sex, religion and any familial history of similar diseases. All eligible patients will be properly counselled and explained about the nature and purpose of the study. Secrecy and confidentiality will be maintained. After informed written consent, patients will be recruited into the study. Informed consent of the patients will be taken after describing the procedure.
Patient preparation.
The participants will be acclimatised for 15 minutes in the examination room by lying on a stretcher with bare legs and feet. Infrared thermal imaging will be performed at rest. The subjects will be allowed to rest in a room to equilibrate body temperature with ambient temperature. No body parts of the patient would be near to or in contact with any hot or cold sources. The patients will be kept away from air convection sources. These precautions should be taken to minimize the variables that might influence temperature measurement. The infrared thermal camera will be positioned 1 meter away from the examination table. [2]
Technique of examination
The thermal images will be recorded after proper patient preparation. Thermal imaging will be performed first and then Doppler examination will be performed. This is because the coupling agent gel may interfere with thermal patterns of images and also to avoid heating effects of Doppler ultrasound which can disturb the image characteristics. The collected data will be analysed and will be compared with Doppler findings of perfusion patterns in the limb. During the Doppler scan, limb arteries of the affected limb will be imaged and the parameters peak systolic velocity, PSV ratio will be recorded. If the plaque is present then the site, size, echogenicity and luminal diameter reduction (stenosis) will be recorded.
By using colour and spectral Doppler, presence of spectral broadening and pattern of spectral wave form will be noted. Doppler findings of affected limb will be compared with thermal imaging patterns in specific angiosomes of different arteries. The findings of both imaging modalities will be correlated and will be further compared with findings of other studies.
Image reconstruction, post processing and interpretation
Nowadays image acquired by thermo graphic camera are directly fed to a digital computer where the images are post processed. The acquired thermography images will be processed using a software which will help in determining temperature at area of interest. Data acquisition software plays an important role in medical infrared thermography.
Statistical Analysis: Segregation of the patients will be based upon differences in demographic and anatomic parameters. The qualitative variables will be expressed in terms of frequencies/percentages and will be analysed using chi-square/Fischer’s exact test. The variables will be considered statistically significant if the p-value is <0.05.
Review of literature
Peripheral arterial occlusion/stenosis mainly caused by atherosclerosis but can also be caused by embolism, vasospasm, inflammation or autoimmunity and trauma.
Detecting peripheral arterial occlusion has evolved since its inception. Ankle brachial pressure index is currently most accepted and suitable screening tool but ankle brachial index has limitations in case of calcified non compressible arteries of lower limb which can lead to increase BP at ankle. Doppler ultrasonography is currently the initial investigation in the diagnosis of Peripheral arterial disease. Doppler is an excellent tool to asses peripheral arterial disease but is comparatively time consuming and cumbersome for initial screening of the community at large scale. Moreover Doppler do not perform well in deeply located arteries in lower limb such as peroneal artery. “Doppler performs better in anterior and posterior tibial artery than peroneal artery”. [8]
Thermography is another imaging modality which is cheaper and faster method in assessment of perfusion in peripheral arterial diseases. Peripheral arterial occlusion will lead to decreased temperature of the affected limb distal to the occlusion. It is because skin temperature in limb is directly proportional to perfusion in the limb. It is due to heat transferred from arterioles to dermis and subsequently from dermis to epidermis. This heat will be radiated from skin surface in the form of infrared rays. These infrared rays are captured by infrared camera and converted to electronic signals for further display and evaluation.
Various studies have suggested the potential use of infrared thermography for monitoring foot temperatures as a means of early detection of onset of foot ischemic disorders. One such study was done by Staffa et al to describe thermal changes of lower limbs in patients before and after endovascular procedure and these findings were compared with ankle brachial pressure measurements (ABI).It was observed in the study that surface temperatures increased by 0.4.c (mean) and ABI by O.17 (mean) from 0.81 in the treated limb after percutaneous trans luminal angioplasty. Thus we can assume that the increase of limb perfusion will be accompanied by increase in surface temperature and ABI. It remains questionable if the observed temperature changes resulted from inflammatory reaction caused by some infection as post-operative complication. However this fact was argued in the study because none of the study subjects suffered from post-operative complication. [9]
Similar study done in 2016 where eight patients with lower extremity arterial occlusive disease undergoing endovascular intervention/ surgical bypass procedure were evaluated by Lin PH and Saines M using FLIR one smartphone based thermo graphic camera. Post-operative thermal imaging, ABI and arterial ultrasound were performed before and 4 weeks after the intervention. It was observed that there was improvement in ankle brachial indices and surface temperatures in thermal imaging after intervention. [10]
In another study done by Huang et al on 51 subjects, cutaneous temperatures at shin and sole were assessed before and after the exercise. There was no significant difference in the resting temperatures of the lower limb at shin and sole between peripheral arterial disease and non-peripheral arterial disease patients. However after exercise cutaneous temperatures elevated in non – peripheral arterial disease patients but the temperature did not elevate in peripheral arterial disease patients. The sole temperature actually lowered in peripheral arterial disease patients dramatically. The exercise induced temperature change (post exercise temperature – pre exercise temperature) was different in two groups (peripheral arterial disease Vs. non peripheral arterial disease patients → -1.25.c Vs. -0.15.c). [2]
In another study done by Bagaqvathippan et al 4 cases of peripheral vascular disease were thermo graphically imaged. Among them a case of 48 year old male patient had low volume dorsalis pedis in the left lower limb while it was normal in right lower limb. The thermal images showed elevated temperatures in left leg medial view probably because of thrombosis and resultant inflammation.6
In a study done by Szentuki A et al infrared video thermography was done for assessment of microcirculation. As it is known, that periodic function of microcirculation in time causes minute temperature changes on the surface of body. These minute temperature changes caused by perpetual oscillation of microcirculation presents themselves as slightly oscillating heat emission intensity and can be detected by infrared thermography. [3]
In a review article by Barbara M et al for reviewing application of infrared thermography in diabetic foot care, thermography was recognised as one of the promising emerging modalities for evaluation of diabetic foot wounds. Thermal changes under the plantar aspect of foot may be the result of vascular compromise, diabetic neuropathy, skeletal changes, infection or combination of these factors. [11]
Bibliography
1.Fowkes FGR, Rudman D, Rudman I, Banyans V, Dannenberg JO et al. Comparison of global estimates of prevalence and risk factors for peripheral artery disease in 2000 and 2010: a systematic review and meta-analysis. The Lancet. 2013; Volume 382, Issue 9901: 1329 – 40
2. Huang CL, Wu YW, Hwang CL, Jong YS, Chao CL et al. The application of infrared thermography in evaluation of patients at high risk for lower extremity peripheral arterial disease. J Vacs Surg. 2011; 54:1074-80.
3. Szentuki A, Kavanagh HS, Grazio S. Infrared thermography and image analysis for biomedical use. Period biol.2011; vol113, No.4:385-92.
4. Lawson R. Implications of surface temperatures in the diagnosis of breast cancer. Can Med Assoc J 1956; 75:309-10.
5. Di Carlo A. Thermography and the Possibilities for its applications in clinical and experimental dermatology. Clin Dermatol 1995;13:329-36.
6. Lahiri BB , Bagavathippan S , Jayakumar T , Philip J. Medical application of infrared thermography : A review. Infrared phyics and technology. 2012 ;55 :221 -235.
7.Bagavathippan S, Karunanithi R, panicker TMR, Kaurath MP, Jagadeesan Ket al. Infrared thermal imaging for detection of peripheral vascular disorders. Journal of medical physics. 2009;34 ,No.1:43-47.
8. Mark EL,Umphrey HR , Weber TM,Robbin ML. peripheral vessels In :Rumack CM, Levine D. Diagnostic ultrasound. 5th edition. Philadelphia. Elsevier 2018 ;vol 2: 964-1010.
9. Staffa E , Bernard V , Vlk D , Mornstein V , Bourek A et al. Infraered thermography as option for evaluating the treatment effect of percutaneous transluminal angioplasty by patient with peripheral arterial disease. Vascular 2017;25 :42-9.
10. Lin PH , Saines M. Assesment of lower extremity ischemia using smartphone thermographic imaging. Journal of vascular surgery and innovative techniques. 2017;3:205-8.
11. Bharara M, Schoess J, Armstrong DG. Coming events cast their shadows before : detecting inflammation in acute diabetic foot and the foot in remission. Diabetes Metab Res Rev. 2012;28:15-20.
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