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At least 937 records · Page 52Linked to original sources
PubMed1988

Dedifferentiated chondrosarcoma of bone with leiomyosarcomatous mesenchymal component: a case report.

Dedifferentiated chondrosarcomas are well-described aggressive tumors arising from low-grade chondrosarcomas and containing high-grade mesenchymal sarcomatous components. These tumors are important to consider in the differential diagnosis of well-defined lytic lesions in the pelvis associated with large soft-tissue components. We present the plain film, computed tomographic, and angiographic findings of the first such reported tumor containing a leiomyosarcomatous component.

Bone Neoplasms↗
PubMed1985

A pressure-flow technique for quantifying temporal patterns of palatopharyngeal closure.

The purpose of this study was to demonstrate a new application of the pressure-flow technique and to determine whether the temporal characteristics of aerodynamic data associated with single-word utterances could reliably differentiate speakers with adequate palatopharyngeal closure from those with inadequacy. The groups included 10 normals, 20 patients with cleft palate who had adequate closure (0.0-0.09 cm2), 20 patients who had borderline closure (0.10-0.19 cm2), and 20 patients who had inadequate closure (greater than 0.19 cm2). The test sound was the nasal-plosive blend /mp/ in the word hamper. The data were processed by a PDP 11/34 computer. The results demonstrate the utility of the pressure-flow technique for studying timing parameters associated with speech and reveal that patients with adequacy of closure can be differentiated from those with inadequacy using timing criteria. Additionally, the data suggest that the perception of nasal resonance in the group with borderline closure appears to be influenced by the timing of closure.

Cleft Palate↗
PubMed1980

Abdominal aortic aneurysms: how can we improve their treatment?

Arteriosclerotic abdominal aortic aneurysms are present in a least 2% of the elderly population of the Western world and their number is increasing. Without treatment 30% of patients with asymptomatic aneurysms live for 5 years, although the risk of rupture becomes greater as the size of the aneurysm increases. Of those with untreated symptomatic aneurysms 80% are dead within a year. Elective repair of aneurysms has a low mortality, and 50% of the patients live for at least 5 years. Symptomatic aneurysms all cause pain and may produce other symptoms from pressure on adjacent structures, distal embolism, acute thrombosis or rupture. In 88% of cases an aneurysm can be diagnosed by physical examination alone; confirmatory tests include soft-tissue roentgenography of the abdomen, ultrasonography, computer-assisted tomography and aortography. Repair is indicated for symptomatic or ruptured aortic aneurysms and for asymptomatic aneurysms over 5 cm in diameter. Early diagnosis and referral for repair is essential for optimum treatment of this common condition.

Aged↗
PubMed1995

Ruptured deep femoral artery aneurysm simulating a soft-tissue sarcoma: a case report.

False aneurysms of the deep femoral artery are uncommon. The presentation in the 80-year-old woman described in this case report was unique in that the pseudoaneurysm was subacute; after an initial hemorrhage, compression of the pseudoaneurysm by the deep femoral artery resulted in a large hematoma suggestive of a soft-tissue sarcoma. The recommended management was angiography, computed tomography and magnetic resonance imaging to differentiate between a false aneurysm and a tumour followed by treatment for the vascular lesion. Such an approach will prevent tumour spread and uncontrollable hemorrhage.

Aged↗
PubMedDate not supplied

Handheld computers in radiology.

The next phase of the digital revolution in medicine is taking place through the dissemination of powerful handheld computers. Handheld computers, or personal digital assistants (PDAs), are no longer considered either a curiosity or a toy. The current handheld computer has many features (Internet access, simple e-mail client software, spreadsheet and database programs, word processing, and digital media) that make it an ideal tool for healthcare providers. Improvements in handwriting recognition, display characteristics, and wireless networking capabilities provide a platform for real-time review of both large static and dynamic repositories of patient data. Although earlier PDA models lacked the ability to display medical images appropriately, current PDAs boast display characteristics that approach low-resolution computer monitors. Although the handheld computer is not yet a reliable option for soft-copy reading, it offers many features that can improve work flow and efficiency for the radiologist. These features include improved personal information management, decision support via access to educational materials, and remote access to radiology-related information systems.

Computers, Handheld↗
PubMed1996

The variability of manual and computer assisted quantification of multiple sclerosis lesion volumes.

The high resolution and excellent soft tissue contrast of Magnetic Resonance Imaging (MRI) have enabled direct, noninvasive visualization of Multiple Sclerosis (MS) lesions in vivo. This has allowed the quantification of changes in the appearance of lesions in MR exams to be used as a measure of disease state. Nevertheless, accurate quantification techniques are subject to inter- and intra-operator variability, which may hinder monitoring of disease progression. We have developed a computer program to assist an experienced operator in the quantification of MS lesions in standard spin-echo MR exams. The accuracy of assisted and manual quantification under known conditions was studied using exams of a test phantom, while inter- and intra-operator reliability and variability were studied using exams of a MS patient. Results from the phantom study show that accuracy is improved by assisted quantification. The patient exam results indicate that assisted quantification reduced inter-operator variability from 0.34 to 0.17 cm3, and reduced intra-operator variability from 0.23 to 0.15 cm3. In addition, the minimum significant change between two successive measurements of lesion volume by the same operator was 0.64 cm3 for manual quantification and 0.42 cm3 for assisted quantification. For two different operators making successive measurements, the minimum significant change was 0.94 cm3 for manual quantification, but only 0.47 cm3 for assisted quantification. Finally, the number of lesions to be monitored for an average change in volume at a given power and significance level was reduced by a factor of 2-4 by assisted quantification. These results suggest that assisted quantification may have practical applications in clinical trials, especially those that are large, multicenter, or extended over time, and therefore require lesion measurements by one or more operators.

Analysis of Variance↗
PubMed2004

Ciliated hepatic foregut cyst: a rare but increasingly reported liver cyst.

We report a case of a ciliated hepatic foregut cyst (CHFC) in the left lobe of the liver in a 42-year-old woman. To date, only 60 cases of these respiratory epithelial lined hepatic cysts have been reported since first described by Friedrich in 1857. CHFC are believed to be congenitally derived from the embryonic foregut and are considered benign lesions that are most often unilocular. Recently, however, there has been documented malignant transformation in these cysts. The majority of patients with a CHFC are asymptomatic and the cyst is usually an incidental finding during abdominal imaging studies or during surgical exploration. Interestingly, 85% of the total number of cases of CHFC have been reported within the last two decades. This recent rise in case reports is likely explained by greater detection because of the dramatic rise in the use of abdominal imaging. In our case, however, ultrasound failed to demonstrate any lesion within the liver and on computed tomography the cyst was more consistent with a soft tissue mass. Therefore, pathologic evaluation was necessary for the correct diagnosis of this liver lesion and to exclude malignancy.

Adult↗
PubMed2002

Estimation of soft-tissue model parameters using registered pre- and postoperative facial surface scans.

Computer-based techniques for the simulation of craniofacial surgical procedures and for the prediction of the surgical outcome have been shown to be very useful. However, the assessment of the accuracy of the simulated surgical outcome is difficult. In this paper, a technique is described which allows to compare the simulated surgical outcome and the actual surgical result. The simulated postoperative patient's appearance is compared to a second surface scan which is obtained postoperatively. The pre- and postoperative surface scans, which are different due to the surgery, are registered employing a robust registration method which minimizes distances of corresponding points. Parameters of the soft-tissue model can be adapted with respect to minimized differences of corresponding points of the simulated postoperative and the actual postoperative surface of a patient's face.

Artifacts↗
PubMed2005

Control of protein functional dynamics by peptide linkers.

Control of structural flexibility is essential for the proper functioning of a large number of proteins and multiprotein complexes. At the residue level, such flexibility occurs due to local relaxation of peptide bond angles whose cumulative effect may result in large changes in the secondary, tertiary or quaternary structures of protein molecules. Such flexibility, and its absence, most often depends on the nature of interdomain linkages formed by oligopeptides. Both flexible and relatively rigid peptide linkers are found in many multidomain proteins. Linkers are thought to control favorable and unfavorable interactions between adjacent domains by means of variable softness furnished by their primary sequence. Large-scale structural heterogeneity of multidomain proteins and their complexes, facilitated by soft peptide linkers, is now seen as the norm rather than the exception. Biophysical discoveries as well as computational algorithms and databases have reshaped our understanding of the often spectacular biomolecular dynamics enabled by soft linkers. Absence of such motion, as in so-called molecular rulers, also has desirable functional effects in protein architecture. We review here the historic discovery and current understanding of the nature of domains and their linkers from a structural, computational, and biophysical point of view. A number of emerging applications, based on the current understanding of the structural properties of peptides, are presented in the context of domain fusion of synthetic multifunctional chimeric proteins.

Amino Acid Sequence↗
PubMedDate not supplied

Soft tissue sarcomas in the general population living near a chemical plant in Northern Italy.

BACKGROUND AND OBJECTIVES: After the notification by a general practitioner of a high frequency of soft tissue sarcomas among subjects living close to the industrial area of the city of Mantua (northern Italy), the local Medical Association carried out a formal epidemiologic investigation to corroborate or falsify the hypothesized excess. Several industrial activities of the area were hypothesized to be a source of environmental pollution that might cause soft tissue sarcomas. METHODS: All general practitioners working in the area were requested to report the cases of soft tissue sarcoma diagnosed in the study area. Person-years of observation were computed for all subjects who ever resided in the area between 1984 and 1997. Expected incidence was computed from the cancer registry covering a nearby province (Varese) and from the pool of Italian cancer registries. Peripheral soft tissue sarcoma and visceral sarcomas were included in the analysis. RESULTS AND CONCLUSIONS: Overall, 20 cases were observed in a 13-year period, 8.87 were expected from the Varese province cancer registry and 7.72 from the pool of Italian registries. The corresponding standardized morbidity ratios were 2.25 (95% confidence interval, 1.34-3.47) and 2.6 (95% confidence interval, 1.6-4.0), respectively. A significant excess persisted after excluding 5 cases that had been the object of the original notification. We hypothesize that the soft tissue sarcoma excess may have resulted from environmental pollution by industrial toxic emissions, which likely included 2,3,7,8-tetrachloro-dibenzo-dioxin.

Adult↗
PubMed1985

Computed tomography of the neck.

The capabilities of CT to distinguish between soft tissue structures of varying densities, bone and air, coupled with the added advantage of utilizing intravascular contrast, particularly suits this method of examination to the study of head and neck disorders. With improved equipment permitting thinner sections and shorter exposure times, applications in head and neck diagnosis are increased. CT is used in the evaluation of salivary gland enlargements, staging of known tumors, the evaluation of a variety of neck swellings and in the assessment of laryngeal and facial trauma. In some cases, CT alone may be the only imaging procedure necessary, while in other situations, CT may comprise an important portion of comprehensive imaging evaluation.

Head and Neck Neoplasms↗
PubMed2001

The cervicocranium: its radiographic assessment.

Acute injuries of the cervicocranium (from the occiput to the second cervical intervertebral disk) may be radiographically obscure due to minimal displacement of fracture fragments, minor alterations of normal anatomic relationships (occipitoatlantal subluxation), or superimposition of normal skeletal structures. With the nasooropharynx adequately distended with air, the normal cervicocranial prevertebral soft-tissue contour is congruent with the anterior cortical margin of the cervicocranium; namely, concave above, convex anterior to, and concave below the anterior tubercle of C1. Alterations of the normal cervicocranial prevertebral soft-tissue contour due to hemorrhage into the retropharyngeal fascial space from subtle fractures or ligamentous injuries should prompt further assessment of the cervicocranium by means of computed tomography (CT). Cervicocranial CT prompted by an abnormal cervicocranial prevertebral soft-tissue contour has yielded a 16% positive injury rate, approximately three times the rate of acute cervical spine injuries reported in the literature.

Adult↗
PubMed1986

Evaluation of the prostate by magnetic resonance imaging.

Forty-seven male patients with suspected prostatic disease underwent magnetic resonance imaging (MRI) of the pelvis on a Picker resistive magnet operating at 0.15 T; 33 had histologically proved adenocarcinoma, 12 benign prostatic hypertrophy, 1 a transitional cell carcinoma, and 1 a seminoma. Eleven normal subjects also were included in the study. The study attempted to (1) define the MRI characteristics of the normal prostate, benign prostatic hypertrophy, and prostatic adenocarcinoma, (2) evaluate various pulse sequences in imaging the prostate, and (3) compare MRI findings with clinical, pathologic, and computed tomography results. Various pulse sequences, including inversion recovery and spin-echo with short and long TE and TR, were used. MRI was sensitive in detecting intracapsular and extracapsular prostatic disease. The finding of inhomogeneous signal texture throughout the gland was a sensitive but nonspecific finding for adenocarcinoma. A focal nodule with prolonged T1 and T2 relaxation times was the most specific MRI finding for adenocarcinoma. Extracapsular spread of neoplasm was often demonstrated, and because of its superior soft-tissue contrast ability, MRI was more accurate than computed tomography in delineating extracapsular extension.

Adenocarcinoma↗
PubMed1997

Magnetic resonance imaging (MRI): considerations and applications in radiotherapy treatment planning.

The emerging utilisation of conformal radiotherapy (RT) planning requires sophisticated imaging modalities. Magnetic resonance imaging (MRI) has introduced several added imaging benefits that may confer an advantage over the use of computed tomography (CT) in RT planning such as improved soft tissue definition, unrestricted multiplannar and volumetric imaging as well as physiological and biochemical information with magnetic resonance (MR) angiography and spectroscopy. However, MRI has not yet seriously challenged CT for RT planning in most sites. The reasons for this include: (1) the poor imaging of bone and the lack of electron density information from MRI required for dosimetry calculations; (2) the presence of intrinsic system-related and object-induced MR image distortions; (3) the paucity of widely available computer software to accurately and reliably integrate and manipulate MR images within existing RT planning systems. In this review, the basic principals of MRI with its present potential and limitations for RT planning as well as possible solutions will be examined. Methods of MRI data acquisition and processing including image segmentation and registration to allow its application in RT planning will be discussed. Despite the difficulties listed, MRI has complemented CT-based RT planning and in some regions of the body especially the brain, it has been used alone with some success. Recent work with doped gel compounds allow the MRI mapping of dose distributions thus potentially providing a quality assurance tool and in a manner analogous to CT, the production of dose-response information in the form of dose volume histograms. However, despite the promise of MRI, much development research remains before its full potential and cost-effectiveness can be assessed.

Abdominal Neoplasms↗
PubMed1996

Three-dimensional modeling for modern diagnosis and planning in maxillofacial surgery.

The existing methods of recording the face in three dimensions are reviewed, and a new method for three-dimensional facial modeling is introduced. The technique utilizes two stereo pairs of videocameras, a stereo pair at each side of the patient's face. The system allows rapid capture of the face in three dimensions and precise measurement of anatomic landmarks. The system can be used to capture the facial image and a cephalogram almost simultaneously, allowing more accurate superimposition of soft and hard tissues. This precision will facilitate development of the surgical treatment plan. A computer program in the early stages of development will use the data generated by this biostereometric measurement system to predict soft tissue changes following orthognathic surgery.

Cephalometry↗
PubMed1978

Computed tomography of the orbit with special emphasis on coronal sections: Part I. Normal anatomy.

Computed tomography (CT) of the orbit is capable of demonstrating soft tissue structures not visualized yet by any other radiological modality. The possibility of obtaining direct coronal slices has added a new dimension to the study. Direct enlargement viewing on the display console reveals many anatomical details. For better evaluation of pathological findings, an accurate anatomical knowledge is required. The purpose of this study is to report on the normal anatomy of the orbital soft tissues made visible by CT, with emphasis on the coronal views.

Adipose Tissue↗
PubMed1978

The base of the skull: a comparison of computed and conventional tomography.

The diagnostic information obtained from 35 examinations of the skull base by computed tomography (CT) was compared with the findings furnished by conventional or blurring tomography (BT). Computed tomography yielded diagnostically valuable information not only on the soft tissues but also on the bony structures. Compared with BT, CT was superior in 40%, equivalent in 40%, and inferior in 20% of the cases in assessing pathological findings involving the bony structures of the skull base. Obviously, CT's additional capability of accurate display of soft tissue changes represents a fundamental diagnostic advantage.

Brain Neoplasms↗