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At least 1,279 records · Page 71Linked to original sources
PubMed1983

Extraskeletal Ewing sarcoma with computed tomography correlation.

Extraosseous Ewing sarcoma--a rare clinical entity--is described and the radiographic and histologic features discussed. Histologically this type of tumor may be differentiated from other soft tissue malignancies, but the ultrastructural glycogen content of the cytoplasm makes it frequently inseparable from the conventional osseous form of Ewing sarcoma. In spite of the presence of a huge paraosseal mass with bone erosion or periosteal new bone, computed tomography was the only preoperative modality able to provide evidence of non-involvement of the marrow cavity. However, histologic documentation is necessary to prove that one is dealing with a totally extraosseous Ewing sarcoma.

Adolescent↗
PubMed1999

Morphological assessment of the soft palate in habitual snoring using image analysis.

OBJECTIVES: Define differences in palatal and uvular dimensions between habitual snorers and healthy nonsnoring control subjects. Document the changes in palatal configuration after different types of palatoplasty. STUDY DESIGN: A prospective controlled clinical study was performed analyzing video recordings of the soft palate and oropharynx of 251 subjects (121 habitual snorers, 79 patients after laser-assisted uvulopalatoplasty ([LAUP], and 51 healthy volunteers). METHODS: The recordings were captured using a rigid endoscope with a reference measure applied to the soft palate and a mark at the junction of the soft and hard palate. Four parameters were studied in the captured pictures after correction for the distortion deformity in fiberoptic endoscopic images: 1) length of soft palate, 2) length of uvula, 3) width of uvula, and 4) distance between posterior pillars. RESULTS: Analysis showed that habitual snorers, compared with healthy volunteers have significantly increased soft palate length (P = .00001), increased uvula length (P = .0002) and width (P = .00001), and narrowed oropharyngeal isthmus (distance between the posterior pillars) (P = .04). In patients studied after LAUP, the length of the soft palate is significantly shorter (P = .00001) than in the preoperative cohort, and the oropharyngeal isthmus is significantly narrower (P = .00001). Moreover, this latter distance is significantly narrower (P = .00001) when compared with healthy volunteers. CONCLUSIONS: Habitual snorers have a long soft palate, a long wide uvula, and a narrowed oropharyngeal isthmus. LAUP shortens and tightens the elongated palate and causes a further reduction in the space between the posterior pillars.

Adult↗
PubMedDate not supplied

Influence of temperature on QCT: implications for mineral densitometry.

OBJECTIVE: Inaccuracies in quantitative CT (QCT) for vertebral bone mineral measurements may result from differences between the temperature of the vertebrae and the calibration standards. This study aims to quantify these effects by using scans of marrow-equivalent materials and computer simulation. MATERIALS AND METHODS: The CT numbers of fat, water, gelatin suspension, and bone were measured within an anthropomorphic phantom at temperatures between -18 and 38 degrees C. A computer simulation was then performed using these materials to represent marrow fat, soft tissue, and bone in varying proportions over this temperature range. Postprocessing single and dual energy QCT calculations were then performed on the data acquired from the simulation. RESULTS: A change of 80 HU in the CT number of water on cooling from 38 to -18 degrees C was demonstrated. An increase of 95 HU in the CT number of fat occurred over the same temperature range. Dry cortical bone showed no change in CT number with temperature changes from 24 to -18 degrees C. In the computer simulation, the fat error associated with single energy QCT for trabecular bone mineral densitometry was 20% less for specimens at room temperature than at body temperature. In simulated frozen specimens, varying marrow fat/soft tissue composition had almost no effect on single energy QCT mineral densitometry. Dual energy QCT methods that use a fat-equivalent reference material were significantly influenced by the temperature of the specimen. CONCLUSION: The fat error of single energy QCT for mineral densitometry may have been underestimated in previous in vitro studies using vertebral specimens scanned at room temperature. In the simulation, the fat error diminished as the temperature of the specimen was reduced and was negligible when frozen. Fat-equivalent reference materials used for dual energy QCT in vivo should have similar X-ray-attenuating properties at room temperature to those of marrow fat at body temperature.

Absorptiometry, Photon↗
PubMed1992

The role of digital image analysis in reproductive biology and medicine.

The use of high-speed computers, direct digitization of video images, and new methods to probe soft tissues has revolutionized our view of biology. Many of these new techniques are now commonly used in several areas of medicine, but their use in reproductive biology has just begun. At present, digital image processing is limited to a few applications in reproductive medicine, including digital colposcopy and the laboratory analysis of spermatozoon motility and cellular morphology. Early implementations of digital image processing experienced problems typical of any newly introduced high technology. Today, however, with careful attention to operational details, digital image processing instruments can be productively used in the clinical diagnosis of cervical cancer, in the laboratory diagnosis of male infertility, and in more basic cell biological research. Such instruments also promise to play a significant role in laboratory quality assurance and control and in technologist training and education. In the near future, digital image processing instruments will also be applied to other areas of reproductive laboratory medicine, such as oocyte evaluation and embryo monitoring in the in vitro fertilization laboratory.

Embryo, Mammalian↗
PubMed2001

[Trauma of the bones of the hand and wrist].

Fractures of the distal radius are common counting for 17 percent of all fractures. With conventional radiography they can be classified readily. Magnetic resonance imaging (MRI) is a suitable technique for the detection of occult forms of fractures and of associated soft tissue injuries. In the wrist, fractures are 10 times less common than in the distal radius, with the scaphoid bone to be involved most commonly. Indications for computed tomography (CT) are complex fractures, occult fractures, or dislocations. MRI should be performed to evaluate the soft tissues, to detect occult fractures, or to analyse osteochondral lesions. Indications for arthrography are injuries of the ligaments or of the joint capsule. Fractures and dislocations of the metacarpal, and the phalangeal bones are the most common fractures of the skeletal system. Conventional radiography is the primary imaging technique, followed by sonography and MRI to detect injuries of the ligaments and tendons.

Austria↗
PubMed2000

[Endoscopic endonasal surgery with image-guidance].

We evaluated the advantages and disadvantages of image-guided endoscopic endonasal surgery for various diseases. Thirty-three patients, including 8 with chronic sinusitis, 14 with paranasal cysts, 1 with paranasal tumor (biopsy), 1 with sellaturcial cyst (Rathke's cleft cyst) and 9 with pituitary tumors were endonasally operated on from September 1998 to May 1999, with an electromagnetic navigation system, The Insta Trak (Visualization Technology Inc. USA). The Insta Trak system is composed of a computer, a metal probe with a nonmetallic suction tube attachment, and a soft-type headset with an electromagnetic sensor. This freehand, armless system compensates well for patient's head movement during surgery, and precludes the need for head fixation. Either straight or curved suction tube (probe) can be used to access almost of all pathological sites in the sinus cavity. Location of the metal probe is displayed on the computer moniter as an intersection point on the axial, coronal and sagital CT images. In all cases, Insta Trak showed the surgeon the appropriate location and direction of each lesion. The Insta Trak also indicated the location of the orbit, optic canal, nasolacrimal duct and/or skull base, thus, preventing intraoperative complications. When the anatomy was distorted by previous surgery and/or when there was uncontrollable bleeding from a severe lesion so that the surgeon had difficulty finding the proper orientation, the usefulness of image-guided surgery was sufficiently recognized. However, the following disadvantages were also pointed out. An additional 15 to 20 minutes is needed for equipment set up and operation, unless the surgeon and the operation room staff are familiar with the machine. The patient's CT image used for navigation relies on data obtained preoperatively, that is to say, it can not reflect morphological changes produced during surgery. Moreover, the surgeon must consider possible errors of the navigational point that may result in the headset during surgery, as well as, errors the machine may originally possess. The image-guided system successfully integrated the most up-to-date computer technology with a surgeon's anatomical knowledge for improved treatment of endoscopic endonasal surgery. However, we also concluded that the system should be used as a surgical supporting device for safer and more adequate procedures.

Endoscopy↗
PubMed1990

Giant-cell tumor of the sphenoid bone: case report and review of the literature.

We report the case of a 23-year-old man with a giant-cell tumor of the sphenoid bone. The radiologic manifestations consisted of an expansile mass arising from the sphenoid bone with extension into the cranial cavity and the nasopharynx. The findings with computed tomography and magnetic resonance imaging best reflected respectively the osseous and soft-tissue extent of the disease.

Adult↗
PubMed2002

Skeletal muscle lymphoma.

Lymphoma usually presents with painless lymphadenopathy. However, it can also present at an extranodal site. Presentation with skeletal muscle infiltration is relatively uncommon and can be confused with a wide variety of both inflammatory as well as neoplastic conditions. We report a patient who presented with progressive swelling of the lower extremity resembling inflammatory necrosis on computed tomography scan, but was later diagnosed as skeletal muscle lymphoma on biopsy.

Female↗
PubMed1984

Surface reconstructions from computerized tomographic scans for evaluation of malignant skull destruction.

The head and neck surgeon is dependent on radiographic technology to diagnose deformity, plan surgery, and evaluate operative results. The development of computerized tomographic scanning has facilitated osseous definition as well as allowed study of intracranial and extracranial soft tissue. Nonetheless, the computerized tomographic image slice format requires an educated interpreter and a fertile imagination for correlation with physical findings. We have created computer software that presents computerized tomographic data as surface images that resemble photographs of the patient or a specimen skull. The program runs on standard computerized tomographic scanners, requires no operator intervention, and is efficient in computation time and space. The surgeon can directly visualize the osseous deformity and mathematically relate it to the overlying soft tissue. The surface images can be viewed from a variety of perspectives, with or without selected structures, such as removing the body of the mandible in the pseudo-Water's projection to demonstrate the palate. The image data can be manipulated to obtain a variety of useful results beyond the images themselves. The addition of this technology to the preoperative evaluation and longitudinal follow-up of patients with head and neck cancer has increased our understanding of the extent of their malignancy.

Aged↗
PubMed1999

Imaging of the rotator cuff and biceps tendon.

Several different imaging techniques are available for evaluating the rotator cuff and biceps tendon. The common disorders of impingement, rotator cuff tears and biceps tendonitis are discussed along with the role which the various imaging modalities can play in establishing their diagnosis. Plain radiographs can be helpful particularly with a history of trauma but give limited information on the soft tissues. Ultrasound is a useful and inexpensive means of assessing the rotator cuff and biceps tendon but has a number of limitations and varying reports on its accuracy. Computed tomography (CT) is most helpful in the evaluation of shoulder trauma but gives limited information on the soft tissues. Magnetic resonance imaging (MRI) is an accurate imaging modality for evaluating the rotator cuff and biceps tendon, allowing visualisation of the soft tissues and the adjacent bony structures.

Arm Injuries↗
PubMed1987

The use of computed tomography scan in unstable hip reconstruction.

Accurate femoral-acetabular relationship was not possible until the advent of the computed tomography scan. Computed tomography scan allows visualization and measurement of femoral torsion, femoral head contour, soft tissue and bony impingements on the femoral head, acetabular configuration and femoral-acetabular relationship.

Acetabulum↗
PubMed1998

The application of volume deformation to three-dimensional facial reconstruction: a comparison with previous techniques.

Facial reconstruction has been widely criticised for its subjective nature and is thus often viewed as a last resort. Recent computer-aided reconstructions, which claim to be objective, may be subject to similar errors. To date, both manual reconstructions and computer-aided techniques have been limited to using the same tissue depth data reference tables. We propose that it is not solely the accuracy of the soft tissue depth data, but the sparsity of landmarks, which contributes to a lack of understanding of how soft tissue changes between the landmarks. The authors feel that a new approach to facial reconstruction using a computer graphics technique known as volume deformation addresses some of the problems encountered in the past. A review of previous methods is provided with discussion of the strengths and limitations of these techniques. In addition, areas are highlighted where the new deformation-based approach may offer possible solutions.

Computer Graphics↗
PubMed1979

[Comments on the problem of demonstrating vertebral bodies in the computer tomogram (author's transl)].

This article emphasises that computer tomography is suitable for disclosing occult destructions in the region of the vertebral column. On the other hand, computer tomography is of great importance for determining the extent of destructions which are already manifest, and any possible spreading of a pathological process in the soft parts to the vertebral column.

Adrenal Gland Neoplasms↗
PubMed1992

[Radiologic diagnosis of the recurrence of soft tissue sarcomas].

We report about the diagnosis of recurrent soft tissue tumors in more than 350 patients using magnetic resonance tomography (MRT) and computed tomography (CT) during the last 5-6 years. MRT turned out to be the method of choice having a sensitivity of about 85% and a specificity of 60-70%, provided that a high resolution technique is used and a paramagnetic contrast agent (gadolinium-DTPA (Gd)) is applied. By performing "dynamic Gd-sequences" a quantification and of the perfusion of a recurrent tumor is possible. Even MRT does not produce a definite tumor-specificity. The alterations of imaging concerning surgical treatment or therapeutic irradiation are extensively discussed. Practical suggestions for the daily routine diagnostic in case of uncertain clinic or symptoms are given.

Adolescent↗
PubMed2005

Computer vision analysis of collagen fiber bundles in the adventitia of human blood vessels.

Numerical simulations, which are based on reliable biomechanical models of blood vessels, can help to get a better understanding of cardiovascular diseases such as atherosclerosis, and can be used to develop optimal medical treatment strategies.The adventitia is the outer most layer of blood vessels and its mechanical properties are essentially determined by the three-dimensional, structural arrangement of collagen fibre bundles embedded in the tissue. Global information such as the orientation statistics of the fibre bundles as well as detailed information as the crimp of the single fibres within the bundles is of particular interest in biomechanical modeling.In order to obtain a sufficiently large amount of data for biomechanical modeling, a fully automatic method for the structural analysis of the soft tissue is required. In this contribution we present methods based on computer vision to fulfill this task. We start by discussing proper tissue preparation and imaging techniques that have to be used to obtain data, which reliably represents the real three-dimensional tissue structure. The next step is concerned with algorithms that robustly segment the collagen fibre bundles and cope with various kinds of artifacts. Novel segmentation techniques for robust segmentation of individual fibril bundles and methods for estimation of their parameters, such as location, shape, mean fibril orientation, crimp of fibrils, etc, is discussed. The proposed algorithms are based on novel perceptual grouping methods operating on the extracted orientation data of fibrils.Finally, we demonstrate the results obtained by our fully automatic method on real data. In addition, for a more quantitative assessment, we introduce a generative structural model that enables the synthesis of three-dimensional fibre bundles with well-defined characteristics.

Adventitia↗
PubMed1990

Current trends in the radiology of the head and neck.

In the head and neck, the changes in radiological practice resulting from the introduction of high resolution computed tomography and magnetic resonance imaging have been far reaching. They relate principally to the greatly improved soft tissue information which is now obtainable, and to the additional possibilities for characterization of soft tissues by intravenous contrast enhancement.

Angiography↗
PubMed1992

[Visualized three-dimensional reconstruction and image analysis in orthopedics and trauma surgery].

Computer tomography is a commonly used technique for detecting pathological alterations in soft tissue and the skeleton. The remote access to image informations as well as the allocation of display and processing tools via networks enables improved diagnostic and therapeutic practice in orthopaedic and traumatologic surgery. The realization of a user friendly image analysis system displays and processes the acquired images in a modality oriented manner. Our method is based on a unique file format and specific evaluation procedures to produce the input data for three-dimensional display and algorithms for the individual design of implants. Our image analysis system can process the data of conventional computer tomographies with three or more mm distance. In contrast to the available systems there is a low significance of radiation effects.

Computer Graphics↗