[Sarcoma of soft tissues in adults. X-ray computed tomographic aspects and evaluation of the response to induction chemotherapy].
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Adolescent↗
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Results for “Soft Computing”
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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↗
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↗
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↗
[The significance of computer tomography in the diagnosis of bone and soft tissue tumors].
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Bone Neoplasms↗
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↗
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↗
[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↗
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↗
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↗
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↗
The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors.
The influence of antiscatter x-ray grids on image quality in cone-beam computed tomography (CT) is evaluated through broad experimental investigation for various anatomical sites (head and body), scatter conditions (scatter-to-primary ratio (SPR) ranging from approximately 10% to 150%), patient dose, and spatial resolution in three-dimensional reconstructions. Studies involved linear grids in combination with a flat-panel imager on a system for kilovoltage cone-beam CT imaging and guidance of radiation therapy. Grids were found to be effective in reducing x-ray scatter "cupping" artifacts, with heavier grids providing increased image uniformity. The system was highly robust against ring artifacts that might arise in CT reconstructions as a result of gridline shadows in the projection data. The influence of grids on soft-tissue detectability was evaluated quantitatively in terms of absolute contrast, voxel noise, and contrast-to-noise ratio (CNR) in cone-beam CT reconstructions of 16 cm "head" and 32 cm "body" cylindrical phantoms. Imaging performance was investigated qualitatively in observer preference tests based on patient images (pelvis, abdomen, and head-and-neck sites) acquired with and without antiscatter grids. The results suggest that although grids reduce scatter artifacts and improve subject contrast, there is little strong motivation for the use of grids in cone-beam CT in terms of CNR and overall image quality under most circumstances. The results highlight the tradeoffs in contrast and noise imparted by grids, showing improved image quality with grids only under specific conditions of high x-ray scatter (SPR> 100%), high imaging dose (Dcenter> 2 cGy), and low spatial resolution (voxel size > or = 1 mm).
Artifacts↗
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↗
Computation and visualization of three-dimensional soft tissue motion in the orbit.
This work presents a method to measure the soft tissue motion in three dimensions in the orbit during gaze. It has been shown that two-dimensional (2-D) quantification of soft tissue motion in the orbit is effective in the study of orbital anatomy and motion disorders. However, soft tissue motion is a three-dimensional (3-D) phenomenon and part of the kinematics is lost in any 2-D measurement. Therefore, T1-weighted magnetic resonance (MR) imaging volume sequences are acquired during gaze and soft tissue motion is quantified using a generalization of the Lucas and Kanade optical flow algorithm to three dimensions. New techniques have been developed for visualizing the 3-D flow field as a series of color-texture mapped 2-D slices or as a combination of volume rendering for display of the anatomy and scintillation rendering for the display of the motion field. We have studied the performance of the algorithm on four-dimensional volume sequences of synthetic motion, simulated motion of a static object imaged by MR, an MR-imaged rotating object and MR-imaged motion in the human orbit during gaze. The accuracy of the analysis is sufficient to characterize motion in the orbit and scintillation rendering is an effective visualization technique for 3-D motion in the orbit.
Algorithms↗
[Role of spiral computed tomography in the assessment of the bone and soft tissue structures of the spine in the postoperative period of degenerative diseases and traumas].
The spiral computed tomography (SCT) was used in examinations of 59 patients with symptoms of neurological disorders at the postoperative period after discectomy, and 82 casualties and 24 patients with degenerative-dystrophic lesions of the spine after correcting-stabilizing operations with plasty of the vertebra with autobone, biositall-XK. An examination of this category of patients and casualties in the nearest and remote terms after operation improves the potentials of SCT-diagnostics of recurrent hernias, epidural fibrosis, spondylites, central and lateral stenoses and allows control of osteoreparation and remodelling of the spine. The improved pathogenetical treatment in these cases shortens the period of disability and does not result in persistent invalidism of the patients.
Cervical Vertebrae↗
Ultrasonography and computed tomography in adenomyomatosis of the gallbladder.
Ultrasonography and computed tomography were performed in 4 patients with adenomyomatosis of the gallbladder of segmental or diffuse type. Cholecystectomy was performed in all cases, and the diagnosis of adenomyomatosis was confirmed histopathologically. Ultrasonography revealed diffuse or segmental thickening of the gallbladder wall with small intramural diverticula. Small stones were also found. The characteristic findings of adenomyomatosis at computed tomography were soft tissue density masses in the gallbladder fossa, associated with a well-delineated, distinct tumor-free space between the mass and the liver, and with small intramural diverticula and calcified stones within the mass. Ultrasonography and computed tomography demonstrate a characteristic appearance of adenomyomatosis.
Adolescent↗
Unusual late sequel of ruptured distal tendon of biceps brachii mimicking a soft-tissue tumor.
OBJECTIVE: We report a rare case of chronic, neglected rupture of the distal biceps brachii which presented with gradually increasing swelling over the left lower arm. Fine-needle aspiration cytology was reported as indicative of a soft-tissue neoplasm. Computed tomography and magnetic resonance imaging were unable to rule out a neoplastic mass. Final histopathology after surgical excision revealed a reparative process. CONCLUSION: Such a presentation of ruptured biceps brachii wherein the clinicoradiological features are misleading and suggestive of a soft-tissue tumor is quite unusual.
Adult↗
Design, synthesis, computational prediction, and biological evaluation of ester soft drugs as inhibitors of dihydrofolate reductase from Pneumocystis carinii.
A series of lipophilic soft drugs structurally related to the nonclassical dihydrofolate reductase (DHFR) inhibitors trimetrexate and piritrexim have been designed, synthesized, and evaluated in DHFR assays, with special emphasis on the inhibition of P. carinii DHFR. The best inhibitors, encompassing an ester bond in the bridge connecting the two aromatic systems, were approximately 10 times less potent than trimetrexate and piritrexim. The metabolites were designed to be poor inhibitors. Furthermore, molecular dynamics simulations of three ligands in complex with DHFR from Pneumocystis carinii and from the human enzyme were conducted in order to better understand the factors determining the selectivity. A correct ranking of the relative inhibition of DHFR was achieved utilizing the linear interaction energy method. The soft drugs are intended for local administration. One representative ester was selected for a pharmacokinetic study in rats where it was found to undergo fast metabolic degradation to the predicted inactive metabolites.
Animals↗