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PubMed1995

Relation between CT axial cross-sectional area of the oropharynx and obstructive sleep apnea syndrome in adults.

PURPOSE: To look for correlation between obstructive sleep apnea syndrome (OSAS) and axial cross-sectional area of the narrowed oropharyngeal lumen. METHODS: Thirty-six men with OSAS and 10 control subjects underwent polysomnography with registration of oxygen saturation and number of sleep apnea episodes and their duration. Nine of them underwent uvulopalatopharyngoplasty and repeated polysomnography. Each polysomnography was followed by high-resolution CT scan with reconstructions in sagittal and coronal planes. Measurements of the axial cross-sectional area of the oropharyngeal lumen were taken at the level of the narrowing. RESULTS: Twenty-seven patients with severe OSAS (high number and prolonged episodes of OSAS and 22% or greater decrease in oxygen saturation) had a narrowed oropharyngeal cross-sectional area less than 50 mm2 wide. The control subjects and 6 patients who had uvulopalatopharyngoplasty without OSAS had a minimal pharyngeal cross-sectional area of 110 mm2. Eight patients with moderate OSAS and 3 patients who had uvulopalatopharyngoplasty and diagnoses of OSAS had intermediate values of the narrowest pharyngeal level--between 60 mm2 and 100 mm2. CONCLUSION: The measurement of the axial cross-sectional area of the pharyngeal lumen can play an important role in evaluation of OSAS and indications for surgery.

Adult↗
PubMed1999

Mass-energy absorption coefficient and backscatter factor ratios for kilovoltage x-ray beams.

For low-energy (up to 150 kV) x-rays, the ratio of mass-energy absorption coefficients for water to air, (mu(en)/rho)w.air, and the backscatter factor B are used in the conversion of air kerma, measured free-in-air, to water kerma on the surface of a water phantom. For clinical radiotherapy, similar conversion factors are needed for the determination of the absorbed dose to biological tissues on (or near) the surface of a human body. We have computed the mu(en)/rho ratios and B factor ratios for different biological tissues including muscle, soft tissue, lung, skin and bone relative to water. The mu(en)/rho ratios were obtained by integrating the respective mass-energy absorption coefficients over the in-air primary photon spectra. We have also calculated the mu(en)/rho ratios at different depths in a water phantom in order to convert the measured in-phantom water kerma to the absorbed dose to various biological tissues. The EGS4/DOSIMETER Monte Carlo code system has been used for the simulation of the energy fluence at different depths in a water phantom irradiated by a kilovoltage x-ray beam of variable beam quality (HVL: 0.1 mm Al-5 mm Cu), field size and source-surface distance (SSD). The same code was also used in the calculation of the B factor ratios, soft tissue to water and bone to water. The results show that the B factor for bone differs from the B factor for water by up to 20% for a 100 kV beam (HVL: 2.65 mm Al) with a 100 cm2 field. On the other hand, the difference in the B factor between water and soft tissue is insignificant (well within 1% generally). This means that the B factors for water may be directly used to convert the 'in-air' water kerma to surface kerma for human soft tissues.

Humans↗
PubMed1989

Temporomandibular joint synovial osteochondromatosis: CT manifestations.

Synovial osteochondromatosis is a rare arthropathy of the temporomandibular joint. We report the computed tomographic findings in two subjects with this disorder. Both patients had increased soft-tissue density in the joint with multiple small calcified densities, many of which displayed peripheral calcification. Extensive erosions of the surrounding bony structures were present, affecting the condylar process and fossa, and, in one instance, the walls of the external auditory and carotid canals were thinned. We believe that computed tomography is superior to conventional imaging techniques and is useful in the depiction of disease and surgical planning in patients with temporomandibular joint synovial osteochondromatosis.

Adult↗
PubMed1978

Computed axial tomography in otorhinolaryngology.

The value of computed tomography in ORL and its applications have been briefly discussed. Better soft tissue detail and its relationship to bony structures is obtained. At the present time this modality may be utilized as a screening test in some suspected cases or as an adjunct of conventional methods. With the technical refinements that are constantly being made, better diagnostic information will be obtained in CT scanning.

Brain Neoplasms↗
PubMed1996

Advanced imaging methods.

Recent developments in imaging sciences have enabled dental researchers to visualize structural and biophysical changes effectively. New approaches for intra-oral radiography allow investigators to conduct densitometric assessments of dento-alveolar structures. Longitudinal changes in alveolar bone can be studied by computer-assisted image analysis programs. These techniques have been applied to dimensional analysis of the alveolar crest, detection of gain or loss of alveolar bone density, peri-implant bone healing, and caries detection. Dental applications of computed tomography (CT) include the detailed radiologic anatomy of alveolar processes, orofacial soft tissues and air spaces, and developmental defects. Image analysis software permits bone mass mineralization to be quantified by means of CT data. CT has also been used to study salivary gland disease, injuries of the facial skeleton, and dental implant treatment planning. Magnetic resonance imaging (MRI) has been used extensively in retrospective and prospective studies of internal derangements of the temporomandibular joint. Assessments based on MRI imaging of the salivary glands, paranasal sinuses, and cerebrovascular disease have also been reported. Magnetic resonance spectroscopy (MRS) has been applied to the study of skeletal muscle, tumors, and to monitor the healing of grafts. Nuclear imaging provides a sensitive technique for early detection of physiological changes in soft tissue and bone. It has been used in studies of periodontitis, osteomyelitis, oral and maxillofacial tumors, stress fractures, bone healing, temporomandibular joint, and blood flow. This article includes brief descriptions of the technical principles of each imaging modality, reviews their previous uses in oral biology research, and discusses potential future applications in research protocols.

Absorptiometry, Photon↗
PubMed1985

Computed tomography of septic joints.

Twenty-six patients with suspected or known septic joints who had been studied by computed tomography were retrospectively reviewed. Eighteen patients (20 joints) proved to have septic arthritis. Computed tomography was advantageous in patients with acute septic arthritis of deep-seated axial joints, such as the hip and sacroiliac, where it demonstrated particular soft tissue swelling as early as 36 hours after the onset of symptoms. In three patients, this finding on computed tomography was helpful in accurately localizing the disease process and facilitating a diagnostic closed needle aspiration biopsy procedure. Four patients had a primary osseous focus of infection in an adjacent epiphyseal region that was documented by computed tomography. Computed tomography was superior to conventional radiology in revealing early articular bone erosion in joints with curved and overlapping articular surfaces in five patients, and resulted in alteration of their treatment. Fat-fluid levels within the suprapatellar bursae were noted in one patient (two joints). Computed tomography is a valuable modality for evaluation of patients with suspected septic arthritis of axial joints, particularly in the acute stage. Furthermore, it is helpful for evaluation of possible periarticular abscess formation and can serve as a guide for a percutaneous drainage procedure. Computed tomography can also be used when articular bone erosion or medullary extension of osteomyelitis is suspected but not fully documented by conventional radiography.

Adult↗
PubMed2000

Three-dimensional virtual reality surgical planning and simulation workbench for orthognathic surgery.

A new integrated computer system, the 3-dimensional (3D) virtual reality surgical planning and simulation workbench for orthognathic surgery (VRSP), is presented. Five major functions are implemented in this system: post-processing and reconstruction of computed tomographic (CT) data, transformation of 3D unique coordinate system geometry, generation of 3D color facial soft tissue models, virtual surgical planning and simulation, and presurgical prediction of soft tissue changes. The basic mensuration functions, such as linear and spatial measurements, are also included. The surgical planning and simulation are based on 3D CT reconstructions, whereas soft tissue prediction is based on an individualized, texture-mapped, color facial soft tissue model. The surgeon "enters" the virtual operatory with virtual reality equipment, "holds" a virtual scalpel, and "operates" on a virtual patient to accomplish actual surgical planning, simulation of the surgical procedure, and prediction of soft tissue changes before surgery. As a final result, a quantitative osteotomy-simulated bone model and predicted color facial model with photorealistic quality can be visualized from any arbitrary viewing point in a personal computer system. This system can be installed in any hospital for daily use.

Cephalometry↗
PubMed2006

Two-year outcomes of computed tomography-based and computed tomography free navigation for total knee arthroplasties.

UNLABELLED: Optimal component position in all planes and well-balanced soft tissues facilitate a good clinical outcome and long-term survival after total knee arthroplasties. We investigated the accuracy of implantation of navigated total knee arthroplasties at 3 months followup and the influence on the clinical outcome at 2 years followup. Forty-four patients (44 procedures) were enrolled in our prospective study. One half of the surgeries were performed using a computed tomography-based navigation system, and half were performed with imageless navigation. Outcomes were based on the Insall knee score parameters, anterior knee pain, patient satisfaction, feeling of instability, and step test. The radiographic parameters were the mechanical axis, tibial slope, lateral distal femoral angle, and medial proximal tibial angle. The radiographic measurements were similar in both groups (patients within +/- 3 degrees inaccuracy range in computed tomography-based/imageless groups; mechanical axis 86%/81%, tibial slope 95%/91%, lateral distal femoral angle 95%/91%, medial proximal tibial angle 91%/95%). The imageless system provided equal radiographic results, but we found improved ligament balancing in the computed tomography free group. The computed tomography-based approach has a good pre-operative planning procedure, but is more expensive and time consuming. LEVEL OF EVIDENCE: Therapeutic Study, Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed1987

Computed tomography of infiltrating benign lipoma.

Lipomas are frequently encountered benign tumors of adipose tissue origin. A lipoma generally develops in the superficial subcutaneous tissues but may occasionally be deep seated, growing between or within muscles. Deep-seated lipomas (excluding body cavities and viscera) have been termed infiltrating benign lipomas, of which there are two varieties--lipoma and angiolipoma. We wish to report three cases of infiltrating benign lipomas. Computed tomography scanning is the diagnostic modality of choice in the evaluation of these tumors.

Aged↗
PubMed1995

Lesser sac herniation through the greater omentum and gastro-pancreatic ligament: report of a case.

We report herein the case of a woman who developed a lesser sac hernia which was especially unusual in that the small bowel prolapsed through a defect in the greater omentum and was thereafter strangulated by a hole in the gastro-pancreatic ligament. The gastro-pancreatic ligament has never before been documented as causing an internal hernia. In our patient, a plain abdominal X-ray demonstrated as soft-tissue mass displacing the stomach to the left while abdominal computed tomography and ultrasonography showed a sac-like encapsulation of the small bowel loops between the liver and stomach. Careful evaluation of these radiographic findings allowed for the preoperative diagnosis of a lesser sac hernia to be made.

Adult↗
PubMed1995

The current state of the art in three dimensional oncologic imaging: an overview.

PURPOSE: To provide an overview of the methods and clinical applications of three dimensional (3D) medical imaging in the oncologic patient. METHODS AND MATERIALS: We briefly outline the techniques currently used to create 3D medical images with an emphasis on their strengths and shortcomings as they relate to oncologic imaging and radiation therapy planning. We then discuss some of the most important and promising oncologic applications of 3D imaging and suggest likely future directions in this rapidly developing field. RESULTS: Since the first application of 3D techniques to medical data over a decade ago, 3D medical images have evolved from relatively crude representations of musculoskeletal abnormalities to detailed and accurate representations of a variety of soft tissue, vascular, and oncologic pathology. The rapid development of both computer hardware and software coupled with the application of 3D techniques to a variety of imaging modalities have expanded the clinical applications of this technology dramatically. CONCLUSIONS: 3D medical images are clinically practical tools for oncologic evaluation and effective radiation therapy planning.

Humans↗
PubMed2006

Spontaneous retropharyngeal hematoma: an unusual presentation of thoracic aortic dissection.

A 78-year-old woman presented to the Emergency Department with spontaneous ecchymosis and swelling of the neck. Ecchymosis was also evident on the posterior pharyngeal wall. A lateral soft tissue radiograph demonstrated a retropharyngeal hematoma, which was confirmed by computed tomography (CT). At this time there was no evidence of airway obstruction and she was admitted for observation. One week after admission she became acutely short of breath, and a chest radiograph at this time showed a large pleural effusion. Pleural drainage confirmed this to be a hemothorax. Subsequent CT revealed a thoracic aortic dissection with blood communicating into both the retropharyngeal space and the pleural cavity. The case highlights both an unusual presentation of thoracic aortic dissection, and also the potential for occult hemorrhage in cases of spontaneous retropharyngeal hematoma.

Aged↗
PubMed1997

Adenoid cystic carcinoma developing in the nasal orbit.

PURPOSE: To describe the clinical, imaging, and histopathologic findings of an adenoid cystic carcinoma that occurred in the medial orbit. METHODS: A 26-year-old man developed a painless soft tissue mass in the nasal aspect of the left orbit. Computed tomography was done, and incisional biopsy performed elsewhere disclosed adenoid cystic carcinoma. Orbital exenteration was performed. RESULTS: Computed tomography showed a 1.5cm mass in the antronasal region of the orbit without bone erosion. Histopathology disclosed adenoid cystic carcinoma. CONCLUSIONS: Although orbital adenoid cystic carcinoma usually originates superotemporally in the main lacrimal gland, it can develop in the nasal orbit, possibly from ectopic lacrimal gland tissue. Adenoid cystic carcinoma should be included in the differential diagnosis of tumors of the nasal orbit.

Adult↗
PubMed1999

Unilateral proptosis in an immunocompetent man as the initial clinical manifestation of systemic Hodgkin disease.

OBJECTIVE: Orbital involvement in Hodgkin disease (HD) is rare. Previously reported cases of HD in patients without the acquired immunodeficiency syndrome have been diagnosed late in the course of established systemic disease. The authors describe an immunocompetent man with orbital infiltration as the initial manifestation of systemic HD. DESIGN: Case report. PARTICIPANTS: A 47-year-old man with acute progressive, painless proptosis of the left eye is described. INTERVENTION: A well-defined, homogeneous soft tissue mass of the superior left orbit was evident on computed tomography, and an incisional biopsy of the nontender mass was performed. RESULTS: The histopathologic findings were characteristic of HD. Systemic investigations showed clinical stage 3A HD. Ten months after completion of hybrid chemotherapy, the patient remained in complete remission from his HD. CONCLUSION: Hodgkin disease presenting initially in the orbit of a patient with the acquired immunodeficiency syndrome has been described previously. The patient presented in this report is the first case of HD in the recent English literature with the initial manifestation in the orbit of an otherwise immunocompetent patient.

Acute Disease↗
PubMed1999

Diagnostic utility of magnetic resonance imaging skeletal survey in a patient with oncogenic osteomalacia.

Oncogenic osteomalacia is a rare paraneoplastic syndrome characterized by hypophosphatemic osteomalacia due to renal phosphate wasting. The same biochemical features are found in patients with X-linked hypophosphatemic rickets/osteomalacia and sporadic hypophosphatemic osteomalacia with unknown etiology. Oncogenic osteomalacia is cured by resection of the responsible tumor. In contrast, patients with other types of hypophosphatemic rickets/osteomalacia need long-term treatment with large doses of active vitamin D3. Therefore, detection of the responsible tumor for oncogenic osteomalacia has great clinical importance. However, there is no standard method for detecting the tumor for oncogenic osteomalacia, and the responsible tumor is often very difficult to be found. We describe a patient with adult-onset osteomalacia due to renal phosphate wasting. Although oncogenic osteomalacia was suspected, cranial, chest, and abdominal computed tomography scanning, urological and otolaryngological examinations, and detailed palpation for soft tissue mass failed to detect the responsible tumor. However, magnetic resonance imaging skeletal survey revealed a tumor in the right femoral bone. Resection of the tumor resulted in normalization of serum phosphate and renal phosphate handling. Because the most frequent causes for oncogenic osteomalacia are tumors in bone or soft tissue, magnetic resonance imaging skeletal survey is a very powerful method for detecting the responsible tumor. Vigorous search for tumors with this method in patients with hypophosphatemic osteomalacia would be helpful not only for proper management of patients, but also for clarifying the identity of sporadic hypophosphatemic osteomalacia.

Bone Neoplasms↗
PubMed1989

Monte Carlo modeling of light propagation in highly scattering tissues--II: Comparison with measurements in phantoms.

Measurements of the fluence-depth distributions and of the diffuse reflectance of 633 nm light have been made in liquid media with optical properties similar to soft tissues. The results are compared with predictions of Monte Carlo computer calculations in order to test the adequacy of Monte Carlo modeling of light transport in tissue. Except at extremely high albedo, the experimental data and the Monte Carlo results agree well for the depth dependence of the fluence as a function of incident light beam diameter and optical absorption and scattering, and for the dependence of the diffuse reflectance on the albedo. The absolute experimental values for the fluence must be renormalized by a factor which varies with the albedo in order to match the model values, and the possible sources of this discrepancy are discussed.

Connective Tissue↗