Anesth Prog 37:127-128 1990
Imaging
Aspects of New Approaches to tie Differential
Diagnosis of Chronic Orofacial Pain Allan Reiskin, DDS, D.Phil. Department of Radiology,
Mt. Sinai Hospital, Hartford, CT. Sinai Imaging Associates 580 Cottage Grove Road Bloomfield, CT
This section raised several important points. First, there is a repertory of imaging modalities using film and/or digitally acquired computer-processed information. These methods are being effectively applied to the diagnosis of disease in the head and neck. Second, sophisticated imaging techniques are being used to further our understanding of normal physiology and of the pathophysiology of pain. Finally, data suggest that existing imaging techniques will become more powerful as clinical experience grows and as new opportunities arise to explore additional applications of existing technology. The anatomic focus of Dr. Katzberg's discussion on contemporary imaging techniques was the temporomandibular joint (TMJ). Plain films and tomograms have been shown to have limited but important uses. The spatial resolution of film records fine detail of hard tissues that is difficult to match. When clinical indicators suggest the presence of bony changes, film-based imaging systems can be valuable. When soft tissues are involved, the contrast resolution of conventional film-based systems can be inadequate, and computerized tomography or magnetic resonance imaging may provide a more realistic approach. It is important to note that in the application of these imaging techniques to the temporomandibular joint, efficacy has always been measured. Subjective impressions of radiologists have been matched against a surgical or histopathologic ground truth. As a result, it has been possible to devise imaging algorithms to assist in the management of patients. Economic cost and biological risk can be realistically assessed. The presentation by Dr. D. Roberts (not included in this volume due to space limitations) was able to point out some of the risks associated with magnetic resonance imaging. In particular, he showed that a fundamental knowledge of the physical and chemical structure of tissue
was essential for correct interpretation. The intensity of the MR signal was found to be highly dependent not only on the concentration of specific substances, but also on the relationship of their magnetic axis to that of the scanner. Accordingly, variations in the organization of collagen in the articular disc of the temporomandibular joint or changes in the orientation of the patient can produce significant variations in signal strength and potential errors in interpretation. The collection of detailed data will help to minimize the risk of false conclusions from MR images.
Spectroscopy also can be used to evaluate chemical changes in muscle associated with function. Evidence that patients diagnosed as having myofascial pain dysfunction show spectroscopic profiles different from normal individuals and even profiles different from normal individuals with fatigued muscles may ultimately alter or expand our approach to patient evaluation. MR imaging and spectroscopy should have far-reaching impact on the diagnosis and management of chronic orofacial pain because of their capability to define changes in a variety of soft tissues including nerves, and because of the potential for recognizing alterations in normal physiology through spectroscopic analysis. Dr. Sadzot and his group demonstrated how the quantity and site of pain receptors can be mapped in nerve tissue through the use of appropriately labeled ligands for opiate receptors. The availability of high specific activity radioligands such as 1"C-carfentanil and "IC-diprenorphine have made it possible to conduct studies in vivo and in humans, thus avoiding many of the problems arising from the application of in vitro methods or from in vivo experiments that require the sacrifice of the subject as an essential step in data collection. Sadzot and his colleagues have shown that it is possible to monitor opiate receptors in volunteers and in patients with disorders of which pain is a significant component. In the foreseeable future it will be possible to evaluate important questions including the relationship of receptor occupant by opiates in relation to the degree of relief from pain, the size of the opiate dose, and other related factors.
Address correspondence to Dr. Allan Reiskin, Sinai Imaging Associates, 580 Cottage Grove Rd., Bloomfield, CT 06002 1990 by the American Dental Society of Anesthesiology
ISSN 0003-3006/90/$3.50
127
128 Imaging Aspects and Differential Diagnosis
Imaging systems, as is the case with other sophisticated technologies, are often developed with some specific objecfive or end-point in mind. The application of these imaging techniques and/or technologies to peripheral problems can be extremely rewarding. We have found photoelectronic digital imaging systems developed for cardiovascular studies to be extremely helpful in the assessment of bones, joints, and soft tissues. In the case of the temporomandibular joint, digital subtraction arthrography has made it possible to recognize loose bodies or wear particles and it can define the size and location of meniscal perforations. Intraarticular scarring and other abnormalities are occasionally seen. Similarly, the use of digital subtractions based on differ-
Anesth Progress 37:127-128 1990
ent x-ray energies can enhance subtle changes in the fine structure of bone that are difficult to see on conventional films and which may be below the spatial resolution of computerized tomograms. The ability to use computer postprocessing techniques has also shown that magnification, contrast enhancement, edge-sharpening algorithms, and other techniques can either increase information extraction from images, or facilitate certain types of diagnostic measurements. In summary, this session has shown that imaging technology is important to the growth of our understanding of the pathophysiology of chronic orofacial pain, while at the same time imaging science plays a rapidly expanding role in the diagnostic testing of patients.
Imaging
Aspects of New Approaches to tie Differential
Diagnosis of Chronic Orofacial Pain Allan Reiskin, DDS, D.Phil. Department of Radiology,
Mt. Sinai Hospital, Hartford, CT. Sinai Imaging Associates 580 Cottage Grove Road Bloomfield, CT
This section raised several important points. First, there is a repertory of imaging modalities using film and/or digitally acquired computer-processed information. These methods are being effectively applied to the diagnosis of disease in the head and neck. Second, sophisticated imaging techniques are being used to further our understanding of normal physiology and of the pathophysiology of pain. Finally, data suggest that existing imaging techniques will become more powerful as clinical experience grows and as new opportunities arise to explore additional applications of existing technology. The anatomic focus of Dr. Katzberg's discussion on contemporary imaging techniques was the temporomandibular joint (TMJ). Plain films and tomograms have been shown to have limited but important uses. The spatial resolution of film records fine detail of hard tissues that is difficult to match. When clinical indicators suggest the presence of bony changes, film-based imaging systems can be valuable. When soft tissues are involved, the contrast resolution of conventional film-based systems can be inadequate, and computerized tomography or magnetic resonance imaging may provide a more realistic approach. It is important to note that in the application of these imaging techniques to the temporomandibular joint, efficacy has always been measured. Subjective impressions of radiologists have been matched against a surgical or histopathologic ground truth. As a result, it has been possible to devise imaging algorithms to assist in the management of patients. Economic cost and biological risk can be realistically assessed. The presentation by Dr. D. Roberts (not included in this volume due to space limitations) was able to point out some of the risks associated with magnetic resonance imaging. In particular, he showed that a fundamental knowledge of the physical and chemical structure of tissue
was essential for correct interpretation. The intensity of the MR signal was found to be highly dependent not only on the concentration of specific substances, but also on the relationship of their magnetic axis to that of the scanner. Accordingly, variations in the organization of collagen in the articular disc of the temporomandibular joint or changes in the orientation of the patient can produce significant variations in signal strength and potential errors in interpretation. The collection of detailed data will help to minimize the risk of false conclusions from MR images.
Spectroscopy also can be used to evaluate chemical changes in muscle associated with function. Evidence that patients diagnosed as having myofascial pain dysfunction show spectroscopic profiles different from normal individuals and even profiles different from normal individuals with fatigued muscles may ultimately alter or expand our approach to patient evaluation. MR imaging and spectroscopy should have far-reaching impact on the diagnosis and management of chronic orofacial pain because of their capability to define changes in a variety of soft tissues including nerves, and because of the potential for recognizing alterations in normal physiology through spectroscopic analysis. Dr. Sadzot and his group demonstrated how the quantity and site of pain receptors can be mapped in nerve tissue through the use of appropriately labeled ligands for opiate receptors. The availability of high specific activity radioligands such as 1"C-carfentanil and "IC-diprenorphine have made it possible to conduct studies in vivo and in humans, thus avoiding many of the problems arising from the application of in vitro methods or from in vivo experiments that require the sacrifice of the subject as an essential step in data collection. Sadzot and his colleagues have shown that it is possible to monitor opiate receptors in volunteers and in patients with disorders of which pain is a significant component. In the foreseeable future it will be possible to evaluate important questions including the relationship of receptor occupant by opiates in relation to the degree of relief from pain, the size of the opiate dose, and other related factors.
Address correspondence to Dr. Allan Reiskin, Sinai Imaging Associates, 580 Cottage Grove Rd., Bloomfield, CT 06002 1990 by the American Dental Society of Anesthesiology
ISSN 0003-3006/90/$3.50
127
128 Imaging Aspects and Differential Diagnosis
Imaging systems, as is the case with other sophisticated technologies, are often developed with some specific objecfive or end-point in mind. The application of these imaging techniques and/or technologies to peripheral problems can be extremely rewarding. We have found photoelectronic digital imaging systems developed for cardiovascular studies to be extremely helpful in the assessment of bones, joints, and soft tissues. In the case of the temporomandibular joint, digital subtraction arthrography has made it possible to recognize loose bodies or wear particles and it can define the size and location of meniscal perforations. Intraarticular scarring and other abnormalities are occasionally seen. Similarly, the use of digital subtractions based on differ-
Anesth Progress 37:127-128 1990
ent x-ray energies can enhance subtle changes in the fine structure of bone that are difficult to see on conventional films and which may be below the spatial resolution of computerized tomograms. The ability to use computer postprocessing techniques has also shown that magnification, contrast enhancement, edge-sharpening algorithms, and other techniques can either increase information extraction from images, or facilitate certain types of diagnostic measurements. In summary, this session has shown that imaging technology is important to the growth of our understanding of the pathophysiology of chronic orofacial pain, while at the same time imaging science plays a rapidly expanding role in the diagnostic testing of patients.
