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At least 181 records · Page 10Linked to original sources
PubMed2003

Early experience with computed tomographic angiography in microsurgical reconstruction.

Preoperative angiography is frequently used in the planning of microsurgical reconstruction. However, several potentially devastating complications can result from angiography, including arterial occlusion and pseudoaneurysm. Computed tomographic angiography is a relatively new technique that can provide detailed information about vascular anatomy as well as soft and bony tissue without the risks of traditional angiography. In addition, three-dimensional image reconstruction uniquely demonstrates anatomical relationships among blood vessels, bones, and soft tissue. Fourteen computed tomographic angiograms were obtained in 10 patients undergoing microsurgical reconstruction of the head and neck, lower extremity, or upper extremity. The average patient age was 46.9 years (range, 22 to 67 years). Charges related to the computed tomographic procedure were compared with those of conventional preoperative imaging for microsurgical repair. At our institution, the average computed tomographic angiogram charge was 1140 US dollars, whereas the average charge for traditional arteriography was 3900 US dollars. When compared with intraoperative evaluation, computed tomographic angiograms demonstrated clinically relevant surgical anatomy. No complications were noted for the radiographic procedure or after free flap reconstruction. Computed tomographic angiography provides high-resolution, three-dimensional arterial, venous, and soft-tissue imaging without the risks of traditional angiogram and at a lower cost.

Adult↗
PubMed1983

Computed tomography of the middle ear in the evaluation of cholesteatomas and other soft-tissue masses: comparison with pluridirectional tomography.

Computed tomographic (CT) scans and tomograms of 60 patients with various soft-tissue masses of the middle ear, including 30 with cholesteatomas, were studied. CT produced excellent images of middle ear soft-tissue masses and appears to be the diagnostic method of choice for cholesteatomas, glomus tympanicum tumors, and other soft-tissue masses. In one patient CT demonstrated pneumolabyrinth resulting from postsurgical fracture of the footplate of the stapes. Pneumolabyrinth is a newly reported CT finding in stapes footplate fracture.

Adolescent↗
PubMed1978

Computed tomography of the paranasal sinuses and face: part I. Normal anatomy.

With the ability to image both bone and soft tissue structures, computed tomography (CT) is capable of visualizing many normal anatomical structures of the paranasal sinuses and face not seen with other radiological techniques. The superficial and deep fat planes, all of the muscles of mastication, and many of the facial muscles are readily identified. The extraocular muscles, optic nerves, and globes are clearly seen. The purpose of this report is to review the normal anatomy of the paranasal sinuses and face imaged by CT in both the transverse and coronal planes.

Face↗
PubMedDate not supplied

Orthogonal polynomials used as soft tissue energy density functions.

A mathematical method is developed for computing the coefficients of soft tissue energy density polynomials, satisfying certain constraints. The polynomial coefficients are computed in the least squares sense. It is demonstrated that this method: (a) determines up to 30 polynomial coefficients whereas the unmodified least squares method based on Maclaurin power series determines up to nine coefficients; and (b) increases numerical stability and accuracy by several orders of magnitude. All computations are carried out in single precision on a LSI-11/23 laboratory minicomputer. The algorithm is particularly useful for on-line data analysis using small laboratory computers.

Connective Tissue↗
PubMed1982

Computed tomography in the evaluation of acquired stenosis in the neonate.

We studied the feasibility of computed tomographic evaluation of the neonatal airway. Three neonatal larynges, removed at necroscopy, were examined by computed tomography. Good resolution of soft tissue, cartilage and airway lumen was obtained in these small specimens. On the basis of these findings two neonates with acquired subglottic stenosis were examined by endoscopy, soft tissue airway radiographs, and computed tomography. Measurements of radiation dose revealed that a computed tomographic study delivered 36% of the mean tissue dose of standard image intensifier fluoroscopy. Computed tomography and fluoroscopy both demonstrated the degree and length of this stenosis accurately. An advantage of CT over conventional imaging procedures was better definition of the cross sectional area of the airway.

Female↗
PubMed2004

Long line positioning in neonates: does computed radiography improve visibility?

OBJECTIVES: To assess the use of soft copy reporting of computed radiography (CR) images in determining intravenous long line tip position in neonates and compare visibility rates with hard copy printed images. METHOD: A retrospective study of all long lines inserted on the neonatal unit over a period of one year was performed. Forty five lines were inserted in 30 neonates over this time. Assessment of the CR images was made by three independent observers by reviewing the films on the viewing console and as hard copy printed films. RESULTS: Accurate identification of the line tip could be made in 66.7% of cases (kappa = 0.9) using hard copy images and 95.6% cases (kappa = 1.0) using soft copy reporting (significant difference: p = 0.002). The difference in percentage visibility using the two techniques was 28.9% (95% confidence interval 10.2% to 36.7%). CONCLUSION: The use of soft copy review of CR image improves the visibility of the line tip position compared with hard copy films and reduces the need for repeat radiographs with/without intravenous contrast.

Catheterization, Central Venous↗
PubMed1985

Calf hematoma mimicking thrombophlebitis: sonographic and computed tomographic appearance.

Five patients with calf hematomas presented with signs and symptoms suggesting thrombophlebitis, obscuring the correct diagnosis. Venography showed no venous thrombosis; further diagnostic studies using ultrasound and/or computed tomography provided the correct diagnosis in all patients. Ultrasound showed a hypoechoic mass clearly demarcated from surrounding soft tissue, while computed tomography showed a well-defined mass whose density depended on the age of the hematoma.

Adolescent↗
PubMed1985

Comparison of computed tomography and digital subtraction angiography of preoperative evaluation of soft-tissue tumors of the limbs.

The preoperative results of computed tomography (CT) (n = 59) and digital subtraction angiography (DSA) (n = 14) were compared with the intraoperative site and the pathological histological finding. The tumor was correctly estimated by CT in 69% (difference less than 20%), and overestimated in 31% (difference greater than 20%). The superiority of CT consisted in the visualization of intratumor alterations and the representation of the muscle compartments concerned and of the spatial relationship of the tumor to the bone and large vessels. Specific morphological CT criteria were found only in rhabdomyosarcoma and liposarcoma. Unequivocial preoperative appraisals with regard to the histological finding to be expected were possible only in the case of lipoma. DSA was helpful for evaluation of vascular involvement and vascularization. The technique contributed to differential diagnosis (malignant-benign) in only 70%. In peripheral soft-tissue tumors (lower leg, forearm), arterial DSA is preferable to venous DSA. Angiography should be employed after the CT investigation and reserved for specific cases.

Adolescent↗
PubMed1982

Comparison of computed tomography and angiography in the evaluation of soft tissue tumors of the extremities.

CT and angiography were performed in 21 patients with soft tissue tumors of the extremities (18 malignant and 3 benign) and the results were compared with the surgical and histopathologic findings. The tumor size was correctly evaluated at CT in 15 of 21 cases and at angiography in 17 of 21 cases. The main reason for overestimation of longitudinal tumor extent seems to be edema surrounding the poles of high grade malignant neoplasms. CT was superior to angiography in demonstrating the intra- or extramuscular tumor location. If only factors important for the surgical planning are considered, angiography yielded such information in 8 cases while CT was of critical value in the preoperative evaluation of 14 patients. It is concluded that CT should precede angiography in the examination of soft tissue tumors of the extremities. Angiography may be superior to CT in demonstrating vascular anatomy in relation to tumors of the medial thigh. With other tumor locations, angiography should be reserved for those lesions where vascular relationships are not adequately demonstrated at CT.

Adult↗
PubMedDate not supplied

High-resolution x-ray imaging at soft diagnostic energies using a silicon photodiode array.

A linear self-scanned silicon photodiode array (PDA) has been used as a high-resolution detector for small object computed tomography using soft diagnostic x rays. The imaging performance of the PDA when used to detect x rays directly has been characterized for x-ray spectra between 24 and 69 kVp. The modulation transfer function (MTF) was measured to 40 cycles/mm (twice the PDA sampling cut-off frequency) by double sampling an edge profile using a half-detector shift. The MTF had no significant energy dependence, a 10% value at 28 cycles/mm, and a 3% low-frequency drop. The detective quantum efficiency zero-frequency value ranged from 1.5% with an 18-keV average-energy beam to 0.4% at 40 keV, and decreased further with increasing spatial frequency. It was found that the effective thickness of the silicon detector was 22 microns. This is typical of the expected diffusion length of minority carriers in doped silicon. An average of 4.6 +/- 1 eV was required to generate one e-h pair in the PDA, consistent with the accepted value of 3.6 eV in silicon. No evidence of radiation damage was observed after an accumulated exposure of over 5000 R. Use of the PDA is demonstrated by generating computed tomographic images using a third-generation (rotate only) reconstruction algorithm. Images of a resolution test phantom, a pen and pencil, a mouse head, and bone biopsy specimen taken from a patient with osteoporosis are shown.

Animals↗
PubMed1985

New observations of soft tissue sarcomas with contrast medium-enhanced computed tomography.

Computed tomography examinations were performed on 74 patients who presented to the Children's Hospital of Philadelphia and the Hospital of the University of Pennsylvania with a known or suspected diagnosis of primary or secondary soft tissue sarcoma. Focal masses were detected on computed tomography study in 59 patients. These masses were classified into three broad categories: centrally necrotic masses with a large predominantly liquefactive center and higher density periphery (29); multilocular, septated masses with distinct linear bands or striations (21); and miscellaneous masses (9). The miscellaneous category included six inhomogeneous and three homogeneous masses. The apparent density differences within these sarcomas were best appreciated on dynamic postcontrast scans. The computed tomography appearance of these sarcomas may be explained by the pathologic findings of cystic degeneration, extensive necrosis, central cavitation, focal hemorrhage, and myxoid changes.

Adolescent↗
PubMed1998

[Pelvic lytic lesion, and the need to suspect osteoporosis-related fractures].

Insufficiency fractures of the pelvis may be overlooked as a cause of hip or groin pain. These fractures occur in the elderly, usually those with pronounced osteopenia of the pelvis. Predisposing factors include corticosteroids, local irradiation and postmenopausal osteoporosis. These fractures are difficult to detect clinically and plain radiographs and other studies may be misleading, delaying diagnosis and treatment. A 65-year-old woman had left groin and hip pain for 2 months with no history of trauma. Plain radiographs showed lytic lesions in the left pubic rami. Bone scan revealed increased uptake in that region, suggesting metastatic bone disease. Computed tomography and magnetic resonance imaging demonstrated fractures in the left superior and inferior pubic rami, with callus formation with no involvement of soft tissues. Quantitative computed tomography indicated low calcium concentration, below fracture threshold. The diagnosis of insufficiency fractures of the pelvis was confirmed by the favorable clinical and radiographic outcome. It is therefore important to be familiar with the appearance and location of these fractures.

Aged↗
PubMed2001

Utility of chest computed tomography for staging in patients with T1 extremity soft tissue sarcomas.

BACKGROUND: National Cancer Center Network (NCCN) and Society of Surgical Oncology (SSO) practice guidelines recommend chest computed tomography (CT) as part of the staging evaluation of patients with extremity soft tissue sarcoma (STS). In the current study, the authors evaluated the use and yield of chest roentgenography (CXR) and selective chest CT to screen for pulmonary metastases in patients with T1 STS. METHODS: The utility of these staging studies was evaluated retrospectively in a cohort of 125 consecutive patients who presented to a tertiary care cancer center with T1 primary (nonrecurrent) extremity STS. Two diagnostic strategies (CXR alone vs. CXR plus chest CT) were evaluated using an incremental cost-effectiveness ratio. RESULTS: The majority of tumors (70%) were high grade. The median sarcoma size was 3.0 cm; 64 of the tumors (51%) were located deep to the investing fascia of the extremity. All patients underwent staging CXR; 1 CXR (< 1%) was suspicious for metastatic disease. Fifty-one patients (41%) also underwent chest CT; 1 chest CT, performed in the patient with a suspicious CXR, revealed metastatic disease. With a median follow-up of 76 months, 19 patients (15%) developed metachronous pulmonary metastases. The relatively low yield resulted in an incremental cost-effectiveness ratio of $59,772 per case of synchronous pulmonary metastasis detected by CXR plus chest CT. CONCLUSIONS: Less than 1% of patients with T1 primary extremity STS were found to have pulmonary metastases that were detectable using a staging algorithm that employs routine CXR with the selective use of chest CT. The findings of the current study do not support current NCCN or SSO practice guidelines for patients with high-grade T1 STS.

Adolescent↗
PubMed2000

Novel microscopic mechanism of intermixing during growth on soft metallic substrates

Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands.

Journal Article↗
PubMed2001

Soft-copy mammographic readings with different computer-assisted detection cuing environments: preliminary findings.

PURPOSE: To assess the performance of radiologists in the detection of masses and microcalcification clusters on digitized mammograms by using different computer-assisted detection (CAD) cuing environments. MATERIALS AND METHODS: Two hundred nine digitized mammograms depicting 57 verified masses and 38 microcalcification clusters in 85 positive and 35 negative cases were interpreted independently by seven radiologists using five display modes. Except for the first mode, for which no CAD results were provided, suspicious regions identified with a CAD scheme were cued in all the other modes by using a combination of two cuing sensitivities (90% and 50%) and two false-positive rates (0.5 and 2.0 per image). A receiver operating characteristic study was performed by using soft-copy images. RESULTS: CAD cuing at 90% sensitivity and a rate of 0.5 false-positive region per image improved observer performance levels significantly (P < .01). As accuracy of CAD cuing decreased so did observer performances (P < .01). Cuing specificity affected mass detection more significantly, while cuing sensitivity affected detection of microcalcification clusters more significantly (P < .01). Reduction of cuing sensitivity and specificity significantly increased false-negative rates in noncued areas (P < .05). Trends were consistent for all observers. CONCLUSION: CAD systems have the potential to significantly improve diagnostic performance in mammography. However, poorly performing schemes could adversely affect observer performance in both cued and noncued areas.

Area Under Curve↗
PubMed2002

Traumatic injuries: imaging of facial injuries.

Facial injuries are common and require radiologic evaluation to plan treatment. The role of imaging is to detect fractures, describe their morphology and topography, and evaluate adjacent soft tissue damage. Computed tomography is the imaging method of choice for an accurate diagnosis and for depicting the complex anatomic structures of the maxillo-facial region. Magnetic resonance imaging plays a limited role, mainly in the assessment of lesions of orbital soft tissues. This paper reviews the most common traumatic injuries of facial bones, paranasal sinuses, orbits and mandible.

Facial Bones↗