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PubMedDate not supplied

Cystic lymphangioma in the adult: an unusual axillary mass.

Magnetic resonance imaging (MRI) has rapidly become an effective technique for the diagnosis and localization of most musculoskeletal diseases. Because MRI lacks ionizing radiation and has superior soft tissue contrast as compared with computed tomography without the need for intravenous contrast material, MRI is emerging as the study of choice for soft tissue masses. This report describes the use of MRI in the evaluation of an unusual axillary soft tissue mass in an adult, a cystic lymphangioma.

Axilla↗

PubMed1995

From the archives of the AFIP. Musculoskeletal angiomatous lesions: radiologic-pathologic correlation.

Vascular lesions of bone and soft tissue are relatively common musculoskeletal neoplasms. Hemangioma is the most frequently encountered angiomatous lesion. Osseous hemangioma commonly involves the spine and calvaria and often has a characteristic radiographic appearance, with either coarsened trabeculae lying adjacent to the vascular channels or multifocal lytic areas creating a honeycomb pattern. Soft-tissue hemangioma is the most frequent soft-tissue neoplasm of infancy and childhood. Radiography and computed tomography (CT) may show phleboliths in cavernous soft-tissue hemangioma. The magnetic resonance (MR) imaging appearance, however, is often more distinctive, because fat overgrowth and serpentine vascular channels can be seen. Lymphangioma usually occurs in the neck and axillae of young children as a soft-tissue mass composed of large cavernous spaces and is well evaluated with CT, ultrasound, or MR imaging. Vascular lesions can also diffusely involve both bone and soft tissue in angiomatosis. A group of more aggressive vascular neoplasms, including hemangioendothelioma, hemangiopericytoma, and angiosarcoma, may have a nonspecific imaging appearance; however, the vascular pattern can be recognized in some cases, allowing radiologic diagnosis. Imaging is important throughout the evaluation of angiomatous lesions for detection, diagnosis, preoperative assessment, and treatment.

Adolescent↗

PubMed1984

Computed tomography of sacral and perisacral lesions.

The sacrum and perisacral soft tissues are not readily amenable to investigation by conventional radiological techniques. Computed tomography (CT) has provided an excellent imaging modality for the evaluation of these areas. This article describes the normal CT anatomy of the sacrum, the CT technique for evaluating the sacrum and perisacral soft tissues and the contribution of CT to the assessment of the many disorders that may involve the sacrum. Conditions discussed include osseous tumors of the sacrum, spinal dysraphism, cauda equina tumors and cysts, lesions arising primarily in the presacral space and sacral trauma. The use of CT scanning of the sacrum following intrathecal administration of Metrizamide is described.

Adolescent↗

PubMed2006

Gait analysis methods in rehabilitation.

INTRODUCTION: Brand's four reasons for clinical tests and his analysis of the characteristics of valid biomechanical tests for use in orthopaedics are taken as a basis for determining what methodologies are required for gait analysis in a clinical rehabilitation context. MEASUREMENT METHODS IN CLINICAL GAIT ANALYSIS: The state of the art of optical systems capable of measuring the positions of retro-reflective markers placed on the skin is sufficiently advanced that they are probably no longer a significant source of error in clinical gait analysis. Determining the anthropometry of the subject and compensating for soft tissue movement in relation to the under-lying bones are now the principal problems. Techniques for using functional tests to determine joint centres and axes of rotation are starting to be used successfully. Probably the last great challenge for optical systems is in using computational techniques to compensate for soft tissue measurements. In the long term future it is possible that direct imaging of bones and joints in three dimensions (using MRI or fluoroscopy) may replace marker based systems. METHODS FOR INTERPRETING GAIT ANALYSIS DATA: There is still not an accepted general theory of why we walk the way we do. In the absence of this, many explanations of walking address the mechanisms by which specific movements are achieved by particular muscles. A whole new methodology is developing to determine the functions of individual muscles. This needs further development and validation. A particular requirement is for subject specific models incorporating 3-dimensional imaging data of the musculo-skeletal anatomy with kinematic and kinetic data. METHODS FOR UNDERSTANDING THE EFFECTS OF INTERVENTION: Clinical gait analysis is extremely limited if it does not allow clinicians to choose between alternative possible interventions or to predict outcomes. This can be achieved either by rigorously planned clinical trials or using theoretical models. The evidence base is generally poor partly because of the limited number of prospective clinical trials that have been completed and more such studies are essential. Very recent work has started to show the potential of using models of the mechanisms by which people with pathology walk in order to simulate different potential interventions. The development of these models offers considerable promise for new clinical applications of gait analysis.

Journal Article↗

PubMed1986

Soft-tissue masses of the locomotor system: comparison of MR imaging with CT.

Magnetic resonance (MR) images and computed tomographic (CT) scans of histologically characterized soft-tissue masses of the locomotor system in 35 patients were compared for image contrast, demonstration of bone destruction, and display of extent and anatomic relationships of the masses. Subjective criteria for predicting malignancy were tested. T1 measurements were made in a few cases. Intensities of masses relative to those of fat and muscle in spin-echo T1-weighted and highly T2-weighted images were evaluated for correlation with tissue type. Subjective value of using coronal and sagittal images was assessed. Because of its superior inherent image contrast and its ability to provide direct sagittal and coronal images, MR was better than CT in demonstrating size and extent of most tumors and their relationships to vascular and nonvascular structures. However, bone destruction was more difficult to see with MR. Except for fatty tumors, MR was not helpful in identifying tissue type. Subjective criteria were of limited value in distinguishing benign from malignant lesions. Moreover, there is currently no credible evidence that T1 or T2 measurements are helpful in this regard. Study results suggest that MR is superior to CT in evaluating soft-tissue masses of the locomotor system. If an MR examination is performed, CT may not be necessary in certain cases unless bone involvement is suspected.

Extremities↗

PubMed1984

CT of the nasopharyngeal region. Normal and pathologic anatomy.

The soft tissue anatomy of the nasopharynx is presented in terms of deglutitional and masticatory muscle layers. Within this framework of analysis, computed tomography can detect relatively early soft tissue changes of nasopharyngeal carcinoma.

Deglutition↗

PubMed2003

Metastases of colorectal carcinoma: comparison of soft- and hard-copy helical CT interpretation.

PURPOSE: To compare soft- and hard-copy computed tomographic (CT) image interpretation with regard to evaluation time and detection rates for hepatic and extrahepatic colorectal metastases in candidates for liver surgery. MATERIALS AND METHODS: In 20 patients with a history of colorectal carcinoma, two radiologists independently evaluated CT data sets. Focal hepatic lesions were characterized as benign or malignant by using a five-point scale. In each patient, soft-copy readouts and hard-copy printouts were compared for nonenhanced hepatic, contrast material-enhanced hepatic, and contrast-enhanced extrahepatic data sets. A stopwatch was used to document evaluation time. Ninety-two hepatic metastases and six extrahepatic metastatic recurrences were detected with the standard of reference--surgical, intraoperative ultrasonographic, and histologic findings. RESULTS: Both observers evaluated the contrast-enhanced hepatic data set significantly faster (P =.026 and.009) by using soft-copy readouts. The contrast-enhanced extrahepatic data set was also evaluated significantly faster (P =.010 and.006) with soft-copy readouts. Detection of hepatic and extrahepatic tumor with soft-copy readouts is not significantly superior to that with hard copies. Detection rates of hepatic metastases for nonenhanced and contrast-enhanced CT for both observers ranged from 50%-80% (46-74 of 92) for soft-copy readouts and 46%-75% (42-69 of 92) for hard copies. Interobserver agreement was highest for contrast-enhanced soft-copy readouts for hepatic metastases. CONCLUSION: Soft-copy readouts of contrast-enhanced CT data sets for the detection of hepatic metastases and extrahepatic metastatic recurrences were evaluated significantly faster than were hard copies, with at least equal sensitivity and with excellent interobserver agreement.

Adenocarcinoma↗

PubMed1984

[Clinical significance of nuclear magnetic resonance tomography in urology. Initial experiences].

NMR tomography, which is based on nuclear magnetic resonance, enables the production of sectional images of the human body without ionising radiation. In particular, the field of urology places great hopes on this new procedures, since the contrast in soft tissue is considerably better than that of computer tomography. Our first clinical results confirm the advantages of the soft tissue differentiation as well as the possibility to judge the large vessels safely and simultaneously without contrast medium, which is advantageous in the detection of tumours in the retroperitoneum and in the region of the kidneys. An improvement of the preoperative staging of urological tumours can be achieved by means of primary three-dimensional images. Only after several years of experience with NMR tomography and all its variations will it be able to evaluate properly, to what extent clinically relevant diagnostic possibilities are offered by the analysis of relaxation values.

Diagnosis, Differential↗

PubMed1997

Lipogranulomas as complications of septorhinoplasty.

BACKGROUND: Nasal tumors caused by lipogranulomas are a rare complication of a rhinoplasty; only 1 report of this occurrence was found in the literature. OBJECTIVE: To present a series of 4 patients with subcutaneous nasal tumors after each had undergone a rhinoplasty, together with a review of the literature and the clinical consequences. DESIGN: Case series. SETTING: Hospitalized care at a university ear, nose, and throat department. PATIENTS: Four patients were referred within 6 months from a single department for consultation because of broad nasal pyramids after each patient had undergone a rhinoplasty. The origin of the deformities was not known. INTERVENTIONS: Ear, nose, and throat and ultrasound examinations and computed tomography (ie, bone and soft tissue examinations). Two patients had undergone revision surgery and histological examinations of subcutaneous fibrous tissue. MAIN OUTCOME MEASURE: Search for the origin of the nasal deformity. RESULTS: All 4 patients had wide nasal pyramids. One of the 4 patients also had subcutaneous tumors of the nasal dorsum, glabella, and medial canthus area; this patient had subcutaneous cystic lesions on computed tomography and ultrasound examination and a foreign body reaction around "empty spaces" on histological examination. The tumorlike lesions were the result of displaced ointment from the endonasal packings. Two of the 4 patients with minor deformities did not undergo any surgical revision, and they still had some moderate reduction of the cystic lesions within 1 year after the rhinoplasty. CONCLUSIONS: Lipogranulomas caused by ointments that are used together with nasal packings are most often reported in the orbit after endonasal sinus surgery. The incidence should be more frequent in patients who undergo a rhinoplasty because connections between the endonasal cavity and the extranasal subcutaneous layer are created routinely by osteotomies or removal of a hump. Thus, postoperative deformities (eg, inadequate narrowing of the bony pyramid or supratip thickening [permanent swelling of the nasal tip]) should be examined by use of computed tomography, if lipid ointments were used endonasally. For prevention, no lipid substances should be applied together with pressure from packings. In the case of a lipogranuloma, surgical removal via an open approach is the treatment of choice.

Adult↗

PubMed2006

Microplane constitutive model and computational framework for blood vessel tissue.

This paper presents a nonlinearly elastic anisotropic microplane formulation in 3D for computational constitutive modeling of arterial soft tissue in the passive regime. The constitutive modeling of arterial (and other biological) soft tissue is crucial for accurate finite element calculations, which in turn are essential for design of implants, surgical procedures, bioartificial tissue, as well as determination of effect of progressive diseases on tissues and implants. The model presented is defined at a lower scale (mesoscale) than the conventional macroscale and it incorporates the effect of all the (collagen) fibers which are anisotropic structural components distributed in all directions within the tissue material in addition to that of isotropic bulk tissue. It is shown that the proposed model not only reproduces Holzapfel's recent model but also improves on it by accounting for the actual three-dimensional distribution of fiber orientation in the arterial wall, which endows the model with advanced capabilities in simulation of remodeling of soft tissue. The formulation is flexible so that its parameters could be adjusted to represent the arterial wall either as a single material or a material composed of several layers in finite element analyses of arteries. Explicit algorithms for both the material subroutine and the explicit integration with dynamic relaxation of equations of motion using finite element method are given. To circumvent the slow convergence of the standard dynamic relaxation and small time steps dictated by the stability of the explicit integrator, an adaptive dynamic relaxation technique that ensures stability and fastest possible convergence rates is developed. Incompressibility is enforced using penalty method with an updated penalty parameter. The model is used to simulate experimental data from the literature demonstrating that the model response is in excellent agreement with the data. An experimental procedure to determine the distribution of fiber directions in 3D for biological soft tissue is suggested in accordance with the microplane concept. It is also argued that this microplane formulation could be modified or extended to model many other phenomena of interest in biomechanics.

Animals↗

PubMed1999

In vivo analysis of microcirculation following closed soft-tissue injury.

Major loss of tissue is an almost invariable consequence of severe closed soft-tissue injury. Clinically, the extent of soft-tissue trauma determines the outcome of complex injuries and significantly influences bone healing. With use of a new animal model, this study quantitatively analyzed microcirculation, i.e., nutritive perfusion and leukocyte-endothelial cell interaction, in skeletal muscle after standardized closed soft-tissue injury. By means of a computer-assisted controlled-impact technique, a severe standardized closed soft-tissue injury was induced in the left hindlimb of 28 rats. The rats were assigned to four experimental groups (n = 7 per group) that differed by time of analysis (1.5, 24, 72, and 120 hours after injury); rats that were not injured served as controls (n = 7). Intramuscular pressure was measured, and microcirculation in the rat extensor digitorum longus muscle was analyzed by in vivo fluorescence microscopy, which allowed assessment of microvascular diameters, functional capillary density, number of rolling and adherent leukocytes in venules, and microvascular permeability. Edema weight gain was quantified by the ratio of wet to dry weight of the extensor digitorum longus muscle. Microvascular perfusion of the skeletal muscle was characterized by a significant reduction in functional capillary density, which was paralleled by an increase in capillary diameter throughout the 120 hours of observation when compared with the controls. Trauma-induced inflammatory response was reflected by a markedly increased rolling and adherence of leukocytes, primarily restricted to the endothelium of postcapillary venules; this was accompanied by increased microvascular permeability, indicative of a substantial loss of endothelial integrity. The microcirculation surrounding the core of the damaged tissue area resembled that of ischemia-reperfusion injury in skeletal muscle, i.e., heterogeneous capillary perfusion, pronounced microvascular leakage, and adherence of leukocytes. Enhanced vascular leakage and leukocyte adherence (24-72 hours after injury) coincided with the maximum intramuscular pressure (which was not indicative of compartment syndrome) and edema formation. These results demonstrate that initial changes, leading to ultimate tissue death, after closed soft-tissue injury are caused on the microcirculatory level. This standardized model provides further insight into microvascular pathophysiology and cellular interactions following closed soft-tissue injury. Thus, it is an adequate tool for testing novel therapeutic interventions.

Animals↗

PubMed1998

Imaging of the cervical spine.

The emergence of multiplanar spiral computed tomography and high-resolution magnetic resonance imaging has resulted in the ability to see cervical spine anatomy and pathologic conditions in detail. Appropriately chosen and performed, these imaging studies can provide an anatomic basis for a clinical diagnosis and a therapeutic plan. In the evaluation of cervical spondylosis, magnetic resonance imaging is more commonly performed than computed tomography because of its superior depiction of soft tissue anatomy, including intervertebral discs and spinal cord disease. However, computed tomography still has a role, particularly in the assessment of osseous neural foraminal stenosis. In cervical spine trauma, routine radiography remains the procedure of choice. Computed tomography is performed in patients who have abnormal plain radiographs or in patients in whom there is a strong clinical suspicion of fracture with inconclusive radiographs. In the neurologically compromised patient, magnetic resonance imaging is useful in the diagnosis of cord and nerve root injury. Magnetic resonance imaging is the most sensitive and specific imaging study in the assessment of spinal infection, including osteomyelitis, discitis, and epidural abscess. Magnetic resonance imaging has also supplanted all other imaging methods in the evaluation of primary and secondary tumors of the spinal cord and spinal column. Despite the precise depiction of cervical spine anatomy provided by these imaging methods, the role of the clinician in determining the true cause of a patient's symptoms is in no way diminished. The presence of an imaging study abnormality does not automatically imply causality.

Cervical Vertebrae↗

PubMedDate not supplied

Attenuation correction and gating synergistically improve the diagnostic accuracy of myocardial perfusion SPECT.

BACKGROUND: The diagnostic accuracy of myocardial perfusion single photon emission computed tomography is limited by soft tissue attenuation. Artifacts may be reduced by attenuation correction (AC) or compensated for by assessment of wall motion in gated images. We studied the benefit of gating and AC, both separately and combined, in improving accuracy. METHODS AND RESULTS: Sixty-six subjects (27 with > or =50% angiographic stenosis, 5 with <50% stenosis, and 34 Bayesian normal volunteers) underwent gated AC single photon emission computed tomography. Images were reconstructed and independently viewed in 4 ways: static with motion correction (MC) only, gated with MC only, static with MC plus blur correction plus AC (referred to as combined corrections [CC]), and gated with CC. Images were interpreted by 2 blinded observers for overall presence of coronary disease and for vascular territory (left anterior descending [LAD], left circumflex [LCx], and right coronary artery [RCA]). Statistical analysis of sensitivity and normalcy was done by means of the Cochran Q test. Overall diagnostic accuracy showed statistically significant improvement (P =.05 for sensitivity, P <.001 for normalcy), progressing from static MC to gated MC to static CC to gated CC (sensitivity/normalcy = 85%/54%, 78%/62%, 93%/77%, and 96%/85%, respectively, for the 4 reconstruction and viewing approaches). Sensitivity was highest in all 3 vascular territories for the combination of gating and CC; normalcy was also highest with the same combination for the LAD and RCA territories; sensitivity/normalcy with this combination was 85%/87% for the LAD, 69%/87% for the LCx, and 89%/87% for the RCA territory. CONCLUSIONS: The combination of gating and CC provides the highest diagnostic accuracy, and gating and AC should thus be considered complementary and synergistic.

Artifacts↗

PubMed1983

Bone-forming gastric metastases in muscle-computed tomographic demonstration.

Bone-forming metastases to soft tissues and muscle are a rare entity. An unusual case of heterotopic ossification occurring within metastases to muscle arising from a primary gastric adenocarcinoma is reported. No bone was found in the primary gastric malignancy. There is one prior report of ossification in muscle occurring in metastases from gastric malignancy, but no previous computed tomographic demonstration of this. The mechanism of osseous metaplasia is discussed, but its precise morphogenesis remains obscure.

Adenocarcinoma↗

PubMed1992

Magnetic resonance imaging of facial vascular anomalies.

In 36 patients, facial vascular anomalies were studied with 46 magnetic resonance (MR) examinations, 9 angiograms, and 5 computed tomographic scans. All lesions were categorized into classic pathologic groups on the basis of radiologic and pathologic studies, clinical examination, and behavior. Overall, 2 juvenile hemangiomas, 3 capillary malformations (port-wine stains), 18 venous malformations, 9 lymphatic malformations, and 4 arteriovenous malformations were found. MR imaging was superior to computed tomography and angiography for demonstrating the precise anatomic extent of the facial vascular anomalies and their relationship to the adjacent soft tissues but was inferior to computed tomography for demonstrating radiopaque structures such as trophic bone changes and phleboliths. MR imaging was also inferior to angiography in determining the nidus and the exact nature of collateral vascular structures in arteriovenous malformations. MR studies confirmed the clinically suspected diagnosis of facial vascular anomalies and demonstrated typical characteristics for each type of lesion. MR imaging is an ideal initial technique to triage patients with facial vascular anomalies for appropriate management, including observation, endovascular therapy, or surgical excision.

Adolescent↗

PubMed1999

Thermoacoustic computed tomography--technical considerations.

We have constructed a thermoacoustic computed tomography scanner for imaging soft tissue in the human body. Thermoacoustic signals are induced in soft tissue by irradiation with 434 MHz rf energy. The thermoacoustic signals are detected by an array of transducers mounted on a hemispherical bowl. A three-dimensional, filtered backprojection algorithm is used to reconstruct rf absorption patterns within soft tissue. We have demonstrated soft tissue differentiation sufficient to delineate the normal internal structures of an excised lamb kidney using safe levels of rf radiation.

Acoustics↗

PubMed2000

Distortion reduction for fast soft straightening of the colon.

RATIONALE AND OBJECTIVES: The purpose of this study was to suppress the geometric distortion associated with soft straightening of the colon by moderately adjusting curved cross sections, which is equivalent to appropriately modifying the underlying electrical field. MATERIALS AND METHODS: A computational mechanism to reduce the geometric distortion associated with soft straightening was developed. Because the cause of distortion is uneven sampling of the colon wall with curved cross sections, the curved cross sections formed according to a numerically simulated electrical field were redistributed in the distortion reduction process. This mechanism can be directly incorporated into a previously published fast soft-straightening algorithm. Simulations were performed to evaluate the effectiveness of the mechanism, and a phantom colon with digitally implanted, spherical polyps was straightened and rendered to visually display the efficacy of the mechanism. RESULTS: The distortion reduction mechanism was advantageous regarding shape preservation of polyps and alleviated distortion substantially. The mechanism occupied only a small portion of the total processing time. CONCLUSION: The distortion reduction mechanism can effectively reduce the geometric distortion associated with soft straightening at little computational cost and has potential for use with computed tomographic colonography.

Algorithms↗

PubMed1994

Personal computer teleradiology interhospital image transmission to facilitate tertiary pediatric telephone consultation and patient transfer: soft-tissue lateral neck and elbow radiographs.

Although teleradiology systems are available commercially, they are expensive ($30,000), and different makes are incompatible with each other, making them unusable for interhospital image transfers. Standard components were added to a personal computer (PC) to build a functional teleradiology unit capable of interhospital image transmission at a low cost ($600 upgrade). This PC teleradiology system was studied to assess its accuracy in the interpretation of soft-tissue lateral neck x-rays with epiglottitis or retropharyngeal abscesses and elbow x-rays with joint effusions, fractures, or both. A radiologist and a pediatric emergency physician were asked to read the PC teleradiology images. Both physicians read 13 of 13 soft-tissue lateral neck x-rays and 15 of 15 elbow x-rays correctly. This study supports the premise that PC teleradiology can be used to facilitate telephone consultation and patient transfers between tertiary pediatric emergency centers by transmitting pertinent radiographic information over a phone line. Although verbal communication can often suffice in a telephone consultation or transfer, there are many instances when visualizing a radiographic image such as an x-ray or computed tomography scan can provide important information that cannot be optimally described verbally. Rural hospitals can form interhospital image transmission links with tertiary center resources. Tertiary centers may elect to organize interhospital image transmission and referral networks with their rural hospital sources.

Adolescent↗