Quantitative assessment of pain-related thermal dysfunction through clinical digital infrared thermal imaging

BACKGROUND: The skin temperature distribution of a healthy human body exhibits a contralateral symmetry. Some nociceptive and most neuropathic pain pathologies are associated with an alteration of the thermal distribution of the human body. Since the dissipation of heat through the skin occurs for the most part in the form of infrared radiation, infrared thermography is the method of choice to study the physiology of thermoregulation and the thermal dysfunction associated with pain. Assessing thermograms is a complex and subjective task that can be greatly facilitated by computerised techniques. METHODS: This paper presents techniques for automated computerised assessment of thermal images of pain, in order to facilitate the physician's decision making. First, the thermal images are pre-processed to reduce the noise introduced during the initial acquisition and to extract the irrelevant background. Then, potential regions of interest are identified using fixed dermatomal subdivisions of the body, isothermal analysis and segmentation techniques. Finally, we assess the degree of asymmetry between contralateral regions of interest using statistical computations and distance measures between comparable regions. RESULTS: The wavelet domain-based Poisson noise removal techniques compared favourably against Wiener and other wavelet-based denoising methods, when qualitative criteria were used. It was shown to improve slightly the subsequent analysis. The automated background removal technique based on thresholding and morphological operations was successful for both noisy and denoised images with a correct removal rate of 85% of the images in the database. The automation of the regions of interest (ROIs) delimitation process was achieved successfully for images with a good contralateral symmetry. Isothermal division complemented well the fixed ROIs division based on dermatomes, giving a more accurate map of potentially abnormal regions. The measure of distance between histograms of comparable ROIs allowed us to increase the sensitivity and specificity rate for the classification of 24 images of pain patients when compared to common statistical comparisons. CONCLUSIONS: We developed a complete set of automated techniques for the computerised assessment of thermal images to assess pain-related thermal dysfunction

Vertebrobasilar arterial occlusions in children

Three children with angiographically confirmed, sudden thrombosis involving the vertebro basilar arterial system are presented. Ten previously reported cases are reviewed with particular regard to possible etiologies. Vertebral artery trauma at the atlantoaxial level is suspected as one important cause. Les auteurs rapportent trois cas d'enfants présentant une trombose soudaine du système artériel vertébrobasilaire, confirmée angiographiquement. Ils revoient dix cas antérieurs, en particulier du point de vue éthiologique. Le traumatisme de l'artère vertébrale au niveau de la charnière cervico-occipitale semble être l'une des causes principale. 3 Kinder mit einer angiographisch nachgewiesenen plötzlich aufgetretenen thrombose des vertebro-basilären Systems werden geschildert, gleichzeitig wird ein Überblick über weitere 10 vorher veröffentlichte Fälle gegeben. Diskussion der möglichen Ätiologie. Es wird darauf verwiesen, daß ein Trauma der A. vertebralis in Höhe des atlanto-axialen Gelenkes eine wichtige Ursache sein kann.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46670/1/234_2004_Article_BF00341593.pd