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PubMed2003

Passive attenuation of cortical pattern evoked potentials with increasing body weight in young male rhesus macaques.

The purpose of our study was to determine changes in amplitudes and implicit times of retinal and cortical pattern evoked potentials with increasing body weight in young, growing rhesus macaques (Macaca mulatta). Retinal and cortical pattern evoked potentials were recorded from 29 male rhesus macaques between 3 and 7 years of age. Thirteen animals were reexamined after 11 months. Computed tomography (CT) was performed on two animals to measure the distance between the location of the skin electrode and the surface of the striate cortex. Spearman correlation coefficients were calculated to describe the relationship between body weights and either root mean square (rms) amplitudes or implicit times. For 13 animals rms amplitudes and implicit times were compared with the Wilcoxon matched pairs signed rank test for recordings taken 11 months apart. Highly significant correlations between increases in body weights and decreases in cortical rms amplitudes were noted in 29 monkeys (p < 0.0005). No significant changes were found in the cortical rms amplitudes in thirteen monkeys over 11 months. Computed tomography showed a large increase of soft tissue thickness over the skull and striate cortex with increased body weight. The decreased amplitude in cortical evoked potentials with weight gain associated with aging can be explained by the increased distance between skin electrode and striate cortex due to soft tissue thickening (passive attenuation).

Aging↗
PubMed2003

An unusual case of CV junction tuberculosis presenting with quadriplegia.

STUDY DESIGN: Isolated tubercular involvement of craniovertebral junction in a human immunodeficiency virus-positive patient causing paraplegia and sudden death with radiologic features is presented. OBJECTIVES: Isolated involvement of craniovertebral junction by tuberculosis causing quadriparesis is a rare entity. The role of imaging features is presented in diagnosis of craniovertebral junction tuberculosis, which is a treatable disease. Early detection of this entity with prompt treatment can prevent a fatal outcome. SUMMARY OF BACKGROUND DATA: Tuberculosis of the cervical spine is a rare and potentially dangerous manifestation of extrapulmonary tuberculosis. The incidence is probably less than 1% of all cases of spinal tuberculosis. However, in the developing countries this constitutes an increasingly important cause of craniovertebral junction instability and cervicomedullary compression. Most of the patients present with pain in the neck and local tenderness. Neurologic deficits of varying degrees have been reported in 24-40% of cases of craniovertebral junction tuberculosis. Quadriplegia followed by sudden death is exceptional (as seen in our case). The incidence of craniovertebral junction tuberculosis in immunocompromised patients is not known. Dramatic recovery is possible if craniovertebral junction tuberculosis is detected early in its course. Prompt medical and surgical treatment may avert a potential catastrophic event in such cases. Imaging methods such as computed tomography and magnetic resonance imaging are diagnostic of this condition and aid in the detection and prompt treatment of the same. METHOD: Frontal radiograph of the cervical spine and chest, and lateral view of cervical spine followed by plain and contrast enhanced computed tomography scan of the cervical spine was performed to detect the lesion. RESULT: These radiographic features were correlated with the clinical findings. The computed tomography findings of bone destruction, prevertebral and extradural peripherally enhancing soft tissue and infiltrating opacities in the lung apexes were consistent with tuberculosis. CONCLUSIONS: The computed tomography findings described in this report are very specific for tuberculosis of the craniovertebral junction. Clinical and radiologic correlation could help in making the early diagnosis and prompt treatment possible.

Adult↗
PubMed2006

Apo2l/Tumor necrosis factor-related apoptosis-inducing ligand prevents breast cancer-induced bone destruction in a mouse model.

Breast cancer is the most common carcinoma that metastasizes to bone. To examine the efficacy of recombinant soluble Apo2 ligand (Apo2L)/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) against breast cancer growth in bone, we established a mouse model in which MDA-MB-231 human breast cancer cells were transplanted directly into the marrow cavity of the tibiae of athymic nude mice producing osteolytic lesions in the area of injection. All vehicle-treated control animals developed large lesions that established in the marrow cavity, eroded the cortical bone, and invaded the surrounding soft tissue, as assessed by radiography, micro-computed tomography, and histology. In contrast, animals treated with recombinant soluble Apo2L/TRAIL showed significant conservation of the tibiae, with 85% reduction in osteolysis, 90% reduction in tumor burden, and no detectable soft tissue invasion. Tumor cells explanted from Apo2L/TRAIL-treated animals were significantly more resistant to the effects of Apo2L/TRAIL when compared with the cells explanted from the vehicle-treated control animals, suggesting that prolonged treatment with Apo2/TRAIL in vivo selects for a resistant phenotype. However, such resistance was readily reversed when Apo2L/TRAIL was used in combination with clinically relevant chemotherapeutic drugs, including taxol, etoposide, doxorubicin, cisplatin, or the histone deacetylase inhibitor suberoylanilide hydroxamic acid. These studies show for the first time that Apo2L/TRAIL can prevent breast cancer-induced bone destruction and highlight the potential of this ligand for the treatment of metastatic breast cancer in bone.

Animals↗
PubMed2005

Just-in-time tomography (JiTT): a new concept for image-guided radiation therapy.

Soft-tissue target motion is one of the main concerns in high-precision radiation therapy. Cone beam computed tomography (CBCT) has been developed recently to image soft-tissue targets in the treatment room and guide the radiation therapy treatment. However, due to its relatively long image acquisition time the CBCT approach cannot provide images of the target at the instant of the treatment and thus it is not adequate for imaging targets with intrafraction motion. In this note, a new approach for image-guided radiation therapy-just-in-time tomography (JiTT)-is proposed. Differing from CBCT, JiTT takes much less time to generate the needed tomographical, beam's-eye-view images of the treatment target at the right moment to guide the radiation therapy treatment.

Algorithms↗
PubMed1990

Deviatoric and hydrostatic mode interaction in hard and soft tissue.

It has been established that many hard and soft tissues have anisotropic material symmetry. It is noted here that the deviatoric and hydrostatic modes interact with each other in a general anisotropic elastic material. In the special case of isotropic, linear elastic, materials these modes are non-interactive. As a consequence of the interaction of these modes encountered in anisotropic materials, the decomposition into hydrostatic and deviatoric modes, and deviatoric mode concepts such as the von Mises effective stress are not appropriate for anisotropic materials in general. The implications of this observation for the presentation of computationally generated stress contours for hard and soft tissues are discussed. It is also pointed out that the mode coupling and mode interaction raise the question of whether anisotropic living tissues respond directly to stress or to some other physical quantity such as strain or strain energy, in view of the recent hypothesis concerning the proliferation and ossification of cartilage.

Adaptation, Physiological↗
PubMed2004

Xanthoma of the sacrum.

Xanthoma is a lesion containing abundant foamy histiocytes most commonly occurring in superficial soft tissues such as skin, subcutis, or tendon sheaths. The involvement of deep skeletal structures, however, is rare and has only been infrequently reported in the English literature. Most xanthomas occur in patients with hyperlipidemic disorders. We report a case of a xanthoma in the sacrum and ilium of a patient with hyperlipidemia type IIa, who had chronic lower back pain for more than 20 years. On radiographs the lesion appeared multiloculated and osteolytic with a thin sclerotic border and containing multiple nodular calcifications within its matrix. Computed tomographic images revealed a presacral soft-tissue mass that also infiltrated the adjacent sacroiliac joint and iliac fossa. On histologic examination, abundant areas of xanthoma cells and cholesterol clefts, typical of xanthoma, were present. The patient received simple curettage of the lesion, and his symptoms were markedly relieved.

Diagnosis, Differential↗
PubMed2001

Three-dimensional virtual-reality surgical planning and soft-tissue prediction for orthognathic surgery.

Complex maxillofacial malformations continue to present challenges in analysis and correction beyond modern technology. The purpose of this paper is to present a virtual-reality workbench for surgeons to perform virtual orthognathic surgical planning and soft-tissue prediction in three dimensions. A resulting surgical planning system, i.e., three-dimensional virtual-reality surgical-planning and soft-tissue prediction for orthognathic surgery, consists of four major stages: computed tomography (CT) data post-processing and reconstruction, three-dimensional (3-D) color facial soft-tissue model generation, virtual surgical planning and simulation, soft-tissue-change preoperative prediction. The surgical planning and simulation are based on a 3-D CT reconstructed bone model, whereas the soft-tissue prediction is based on color texture-mapped and individualized facial soft-tissue model. Our approach is able to provide a quantitative osteotomy-simulated bone model and prediction of postoperative appearance with photorealistic quality. The prediction appearance can be visualized from any arbitrary viewing point using a low-cost personal-computer-based system. This cost-effective solution can be easily adopted in any hospital for daily use.

Humans↗
PubMed2003

Can FDG PET be used to successfully direct preoperative biopsy of soft tissue tumours?

Magnetic resonance imaging (MRI) has been the most useful tool in the anatomical definition of soft tissue sarcoma, although there remains the problem of defining the lesions as benign or malignant. The management of such lesions requires biopsy prior to surgical resection. If the most malignant area could be defined more accurately, then this area could be targeted for biopsy. Fluorodeoxyglucose positron emission tomography (FDG PET) has been found to be useful in identifying malignancy and variations in grade in soft tissue masses. The aim of this study was to assess the use of FDG PET scanning with or without co-registered MRI to indicate the most appropriate biopsy site. Twenty consecutive patients presented with soft tissue masses with clinical signs of malignancy. All patients underwent MRI and FDG PET scanning and the two images were co-registered. A biopsy site that was the most likely to be malignant was defined on the PET scan. All patients underwent an initial biopsy and then complete surgical resection of the mass. The histological results from the mass were compared with those from the biopsy specimen obtained from the site suggested by the PET scan. In malignant masses the biopsy site suggested by the FDG PET scan was found to be representative of the most malignant site on the whole mass histology. Benign lesions had low or no FDG uptake. In no case did the co-registered image add significantly to the appropriate biopsy site. FDG PET can be used to appropriately direct biopsy in soft tissue sarcoma and potentially may lead to computed tomography/MRI directed outpatient biopsy prior to definitive treatment.

Adult↗
PubMed1986

[Traumatology of the midface--diagnostic and therapeutic guidelines for the practicing ENT physician from the viewpoint of the radiologist].

Local and combined facial fractures are usually correctly diagnosed by conventional plain films in conjunction with the clinical picture. If the image quality is reduced due to soft tissue swelling of problems in positioning a multiply injured patient, conventional tomography or computed tomography (CT) are indicated. The advantages of CT are the detailed imaging of soft tissue and bone structures; in patients with skull trauma, CT of the facial bones can be combined with cranial computed tomography without re-positioning the patient. CT proved to be the most accurate method for the evaluation of blow-out-fractures of the orbit. The radiation dose is less and the investigation time is shorter compared to conventional tomography in the demonstration of facial fractures. Conventional tomography is indicated when artefacts caused by dental fillings reduce the image quality of CT.

Facial Bones↗
PubMed1983

Selective application of CT in the management of laryngeal trauma.

The clinical course of five patients with varying degrees of laryngeal trauma are presented to illustrate the predictive value of computed tomography (CT) in the management of laryngeal trauma. Computed tomography visualizes well the laryngeal skeleton, soft tissues and airway in the injured larynx. Cost effectiveness of CT scanning is an important consideration, and the authors have chosen their case examples to restrict this examination to selected patients.

Accidents, Traffic↗
PubMed1999

Differences in soft tissue profile changes following mandibular setback in Chinese men and women.

PURPOSE: This study investigated the soft tissue profile changes after surgical correction of mandibular prognathism in Chinese patients and evaluated the sex differences in the ratios of soft tissue to hard tissue change. PATIENTS AND METHODS: Forty-three adult Chinese patients (18 men and 25 women) with mandibular prognathism were treated by intraoral oblique or vertical ramus osteotomy. Lateral cephalometric radiographs were taken presurgically and between 6 to 12 months postsurgically, and specific soft and hard tissue points were digitized and analyzed with a computer-aided system. RESULTS: As a result of surgical setback of the mandible, the soft tissue to hard tissue change ratios were: Li:Ii = 0.71:1, Si:B = 0.90:1, Pg':Pg = 0.94:1 for the males; and Li:Ii = 0.82:1, Si:B = 0.92:1, Pg':Pg = 1.06:1 for the females. CONCLUSION: The changes in soft tissue were closely correlated with the hard tissue movement after surgical setback of mandible. The average ratios of soft tissue to hard tissue change in horizontal direction appear to show a gender difference, which suggests the need for different ratios when predicting the results of orthognathic surgery.

Adult↗
PubMed1981

[On the diagnosis of extraocular muscle disease. Clinical application of computer reformations (author's transl)].

The clinical application and differential diagnostic value of computer reformations in patients with Graves' disease and ocular myositis are demonstrated. Computer reformations parallel to the course of the muscle allow the identification of abnormal soft tissue densities on axial section as a swelling of individual muscles. Computer reformations perpendicular to the course of the muscle demonstrate its true cross sectional diameter. In most clinical instances, the rectus muscles are sufficiently visualized on computer reformations 90 degrees to the orbital axis. The vertical recti are then shown as true cross sections, whereas the horizontal recti are dissected in an equally oblique plane. A swelling of the inferior oblique muscle is well visualized by sagittal reformations lateral to the insertion of the inferior rectus muscle. With the use of computer reformations muscle enlargement can be diagnosed with certainty. They therefore provide valuable information in the evaluation of motility disturbances as well as in the analysis of specific patterns of muscle involvement in various orbital diseases.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Pet fish radiography: technique and case history reports.

Radiography can be used to aid in the diagnosis and treatment of pet fish diseases. Handling, restraint and radiographic technique for the radiographic examination of pet fish is described. Quality diagnostic images can be obtained with standard radiographic equipment and radiographic techniques. Fishes with undifferentiated sarcoma, swim bladder herniation and scoliosis are three clinical examples that are described where radiography was used in the management of the patient. Conventional radiography appears to be best for evaluating skeletal and swim bladder diseases. Alternate imaging techniques such as computed tomography and magnetic resonance imaging may enhance the evaluation of coelomic soft tissue structures.

Air Sacs↗
PubMed1997

Analytical approaches to the determination of pressure distribution under a plantar prominence.

INTRODUCTION:: The purpose of the current research was to develop an analytical model for the interface between the metatarsal head, surrounding soft tissue, and the shoe. Results of 'peak plantar pressures' computed from this model were compared to previous results obtained from clinical data and from a finite element (FE) model. METHODS:: An analytical model for determining the pressure distribution at the interface between the foot and shoe insole was developed based on the solution[Figure: see text] for a rigid cylinder and a single elastic layer mounted on a rigid half-space originally developed by Meijers (see Figure 1). The rigid cylinder was used to represent the metatarsal head region (including bone and soft tissue). Material properties and loading conditions were chosen to reflect those used by Lemmon et al. for 'Normal' and 'Reduced' soft tissue thickness cases. RESULTS:: Peak pressures computed from the analytical model are plotted against insole thickness in Figure 1, alongside experimental and FE model data from Lemmon et al. Correlations between analytical, FE, and experimental results for both the Normal and Reduced soft tissue cases were all highly significant (r(2) = 0.86, p < 0.01). DISCUSSION:: The analytical model produced unrealistically high peak pressures compared to the FE and experimental results, with differences of approximately one order of magnitude. This was not surprising, given that the entire metatarsal head region (soft tissue included) was modelled as a rigid cylinder. The soft tissue on the bottom of the foot, and the much greater surface area over which the loads are carried in the real case, contribute greatly to reducing these peak pressure values. However, the downward trend in peak pressure with increased insole thickness was retained. CONCLUSION:: It is anticipated that the use of more accurate and detailed models will greatly improve the initial results.

Journal Article↗
PubMed2005

From 2-dimensional cephalograms to 3-dimensional computed tomography scans.

Computed tomography is entering the orthodontic specialty as a mainstream diagnostic modality. Radiation exposure and cost have decreased significantly, and the diagnostic value is very high compared with traditional radiographic options. However, 3-dimensional data present new challenges and need a different approach from traditional viewing of static images to make the most of the available possibilities. Advances in computer hardware and software now enable interactive display of the data on personal computers, with the ability to selectively view soft or hard tissues from any angle. Transfer functions are used to apply transparency and color. Cephalometric measurements can be taken by digitizing points in 3-dimensional coordinates. Application of 3-dimensional data is expected to increase significantly soon and might eventually replace many conventional orthodontic records that are in use today.

Algorithms↗
PubMedDate not supplied

Hypertrophic synovitis and osteoarthritis of the cervical facet joint. Report of two cases.

We report two cases of cervical facet joint osteoarthritis associated with radiculopathy. Contrast-enhanced computed tomography showed a halo of enhancing soft tissue surrounding the facet joints and narrowing the neural foramen. Hypertrophic synovial masses were discovered and removed at the time of operation in each case, resulting in relief of the radicular symptoms.

Aged↗
PubMed2006

Serous otitis media revealing temporal en plaque meningioma.

OBJECTIVES: To present a series of temporal en plaque meningiomas involving the middle ear or mastoid, whose main symptoms suggested a serous otitis media. STUDY DESIGN AND SETTINGS: Multicentric retrospective study reviewing clinical records originating from eight tertiary referral centers. MATERIALS AND METHODS: The clinical records of 10 patients presenting with signs and symptoms suggesting serous otitis media and whose neuroimaging studies revealed a temporal en plaque meningioma involving the middle ear or mastoid are reported. RESULTS: All the patients were women, ranging from 49 to 71 years old. The delay between the onset of symptoms and the diagnosis of meningioma varied from 1 to 10 years. All the patients underwent various procedures usually applied for the treatment of serous otitis media, which failed in all the cases, particularly ventilating tube placement, which was followed by severe episodes of discharge. In all cases, the computed tomographic scans showed three imaging signs: soft tissue mass filling the middle ear or mastoid, hyperostosis of the petrous bone, and hairy aspect of the intracranial margins of the affected bone. This imaging triad must alert the otologist of the possibility of intracranial meningioma. Magnetic resonance imaging was the method of choice to assess the diagnosis of intracranial meningioma involving the middle ear or mastoid. When analyzing management options, it appeared that conventional middle ear procedures were inefficient. CONCLUSION: Temporal en plaque meningioma involving the middle ear or mastoid can mimic a serous otitis media. A computed tomographic scan is recommended for cases of atypical or prolonged unilateral serous otitis media to investigate indirect signs of a meningioma, which has to be confirmed with magnetic resonance imaging.

Aged↗