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PubMed2001

QSAR modeling of large heterogeneous sets of molecules.

In aquatic toxicology, QSAR models are generally designed for chemicals presenting the same mode of toxic action. Their proper use provides good simulation results. Problems arise when the mechanism of toxicity of a chemical is not clearly identified. Indeed, in that case, the inappropriate application of a specific QSAR model can lead to a dramatic error in the toxicity estimation. With the advent of powerful computers and easy access to them, and the introduction of soft modeling and artificial intelligence in SAR and QSAR, radically different models, designed from large noncongeneric sets of chemicals have been proposed. Some of these new QSAR models are reviewed and their originality, advantages, and limitations are stressed.

Forecasting↗

PubMed1982

[Computed tomography and ultrasound: comparison with intraoperative findings of large metastases in the neck (author's transl)].

The evaluation of soft tissue lesions in cases with extensive metastases, in the neck is of great importance. The therapeutic concept will depend upon the size distribution and infiltration of the metastases into the structures of the lateral neck. The limiting factors include the great vessels of the neck, the deep neck muscles, the base of the skull, the mediastinum and the proximal parts of trachea and oesophagus. The timing of therapy (operation, radiation and cytostatic therapy) can be planned according to these factors. Computed tomography and ultrasound provide the information about the soft tissues of the neck. Spread, size and site of infiltration can be fairly estimated as shown in 25 patients which have been operated on.

Adult↗

PubMed1982

Comparison of computed tomography and pluridirectional tomography of the temporal bone.

During pluridirectional tomography dense bone creates ghost shadows that simulate chronic disease and soft-tissue masses within the middle ear cavity. This effect was demonstrated in three dried skulls. Cholesteatomas were simulated in three more temporal bones with a mixture of 2% iodine in paraffin. Three different high-resolution computed tomographic scanners clearly demonstrated middle ear anatomy and the simulated soft-tissue masses in the skulls.

Cholesteatoma↗

PubMed1979

Computed tomography of paranasal sinus tumors.

Thirty-two patients with histologically proved malignant disease involving the paranasal sinuses were studied by CT. The radiological features of tumor were sinus opacification, a soft-tissue mass, bone erosion and/or displacement, sclerosis, and new-bone formation. Measurements of tissue densities were not helpful in distinguishing tumor from benign disease. Significantly greater tumor extent was demonstrated by CT than by conventional methods in 15 patients; the additional tumor most commonly involved the pterygoid region or orbit. The clinical importance of various directions of tumor spread is emphasized.

Adolescent↗

PubMedDate not supplied

Use of radiography, computed tomography and magnetic resonance imaging for evaluation of navicular syndrome in the horse.

Radiographic evaluation of navicular syndrome is problematic because of its inconsistent correlation with clinical signs. Scintigraphy often yields false positive and false negative results and diagnostic ultrasound is of limited value. Therefore, we assessed the use of computed tomography and magnetic resonance imaging in a horse with clinical and radiographic signs of navicular syndrome. Cadaver specimens were examined with spiral computed tomographic and high-field magnetic resonance scanners and images were correlated with pathologic findings. Radiographic changes consisted of bony remodeling, which included altered synovial fossae, increased medullary opacity, cyst formation and shape change. These osseous changes were more striking and more numerous on computed tomographic and magnetic resonance images. They were most clearly defined with computed tomography. Many osseous changes seen with computed tomography and magnetic resonance imaging were not radiographically evident. Histologically confirmed soft tissue alterations of the deep digital flexor tendon, impar ligament and marrow were identified with magnetic resonance imaging, but not with conventional radiography. Because of their multiplanar capability and tomographic nature, computed tomography and magnetic resonance imaging surpass conventional radiography for navicular imaging, facilitating earlier, more accurate diagnosis. Current advances in imaging technology should make these imaging modalities available to equine practitioners in the future.

Animals↗

PubMed1986

Fast computer processing for tissue highlighting in computed tomographic cross-sectional imaging and digital scan projection radiography.

A simple, fast, computer method of simultaneously highlighting edge detail and emphasising soft-tissue contrast is discussed. An objective comparison is made with conventional blurred mask subtraction using the signal-to-noise ratio from phantom scans. The use of the algorithm for inner ear studies and digital scanned projection radiography is presented.

Computers↗

PubMed2006

Image guided surgery: new technology for surgery of soft tissue and bone sarcomas.

AIM: Providing the surgical oncologist with a new means of performing safe and radical sarcoma surgery with the help of image guidance technology. METHOD: Two patients with pelvic sarcomas were operated upon with the help of an intra-operative navigation system. The technology of image guided surgery is described in one patient with a retroperitoneal sarcoma invading the bony pelvis and another patient with a chondrosarcoma of the iliac crest. RESULTS: We show that this new procedure enables optimal radical surgical resection with minimal treatment related morbidity or loss of function. CONCLUSION: Image guided surgery is a new technical tool in sarcoma surgery.

Adult↗

PubMed1984

Cervical chordoma presenting with intervertebral foramen enlargement mimicking neurofibroma: CT findings.

A cervical chordoma, confirmed at surgery, presented on plain spine films as a focal enlargement of the intervertebral foramen and mimicked the characteristic appearance of cervical neurofibroma. Computed tomography (CT) of the cervical spine was obtained immediately following metrizamide myelography; it demonstrated a soft-tissue mass in the enlarged intervertebral foramen that extended posteriorly to compress the spinal cord and anteriorly to compress the hypopharynx. The mass was sharply demarcated, inhomogeneous, and low in attenuation; CT density measured between those of cerebrospinal fluid and muscle. Although this CT appearance is not specific for cervical chordoma, it is unusual for neurofibroma. Cervical chordoma should be considered in the differential diagnosis of focal enlargement of cervical intervertebral foramina.

Adult↗

PubMed1999

Sino-orbital aspergillosis in acquired immunodeficiency syndrome.

OBJECTIVE: To describe the clinical features, causes, imaging characteristics, treatment, and outcome of patients with the acquired immunodeficiency syndrome (AIDS) and sino-orbital aspergillosis. DESIGN: Records of 5 patients were reviewed. Results of imaging and histopathologic examinations and clinical courses of the patients were studied. RESULTS: There were 3 women and 2 men (mean age, 34.0 years). All had received a diagnosis of AIDS, and mean CD4+ cell count was 0.014 x 10(9)/L (14 cells/mm3). Computed tomographic scanning exhibited heterogeneous, enhancing sino-orbital soft tissue lesions with bony erosion, and magnetic resonance imaging disclosed soft tissue masses hypointense on T1- and T2-weighted images. The infection involved 1 or more paranasal sinuses, with extension into the right orbit in 3 patients and into the left orbit in 2. Patients were treated with aggressive surgical debridement and intravenous antifungal agents. In addition, local irrigation of amphotericin B was performed in 3 patients. Aspergillus fumigatus was found to be the cause in all 5 patients. Intracranial extension developed in 4 patients, and all subsequently died. The 2 longest surviving patients were the only ones being treated with protease inhibitors. Three patients had a history of frequent marijuana smoking. CONCLUSIONS: Sino-orbital aspergillosis is a progressive, relentless, and usually fatal opportunistic infection of advanced AIDS. Patients are first seen with long-standing headache and proptosis with minimal external inflammatory signs. Marijuana smoking may increase the risk for development of sino-orbital aspergillosis in these patients. Aggressive surgical and medical treatment, combined with newer combination therapies using protease inhibitors, may improve the longevity of these patients.

AIDS-Related Opportunistic Infections↗

PubMed2000

Avoidance model for soft particles. II. Positional ordering of charged rods.

The phase diagram of parallel, charged spherocylinders is computed. The topology of the diagram is found to be similar to the uncharged one, but there are several qualitative changes. Regions of phase coexistence are significantly narrower and positional ordering is stabilized by the electrostatic repulsions. The nematic phase occupies a very narrow zone. We suggest that soft repulsions between surfactant micelles may be responsible for the absence of a nematic phase in most surfactant systems. We also present comparisons with the observed nematic-smectic phase transition for fd and tobacco mosaic virus particles.

Entropy↗

PubMed1990

[Histologic grade, DNA content and image analysis in soft tissue tumors].

Flow cytometry and image analysis technique were used to quantitate the nuclei of various soft tissue tumors. A single representing section from soft tissue sarcoma was used for histologic grading. Histologic and cytometric comparative analyses showed that all 21 benign tumors were diploid. Among 62 cases of soft tissue sarcoma, 45 (73%) were aneuploid. There was a significant difference in the nuclear area between benign and malignant tumors (P less than 0.01), diploid and aneuploid tumors (P less than 0.05). The two new techniques are valuable in cellular quantitative measurement for soft tissue tumors.

Adolescent↗

PubMed2005

Computer aided surgical reconstruction after complex facial burn injuries -- opportunities and limitations.

In severe facial burn injuries with extensive destruction of anatomical structures, cosmetic and functional outcome of treatment are frequently not satisfactory. Although operative therapy is being continuously refined, the variety and proximity of structures in the facial region is considered a major challenge in reconstructive surgery. We present the case of a 16-year-old patient with a severe facial burn injury. In planning the reconstructive procedures, we used a multimodal approach employing data from computerized tomography imaging, as well as from surface laser scanning, which provided three-dimensional visualization of facial soft tissues. Amount and pattern of structural loss could thus be determined more precisely and studied more vividly than by inspection of two-dimensional imaging alone. Anatomical features to be reconstructed could be projected onto the skin area of the prelaminated vertical rectus abdominis muscle (VRAM) flap that has been chosen to cover the defect. Prior to surgery, correction of the defects was simulated and the results of the virtual procedure superimposed on a three-dimensional head model of the patient. Tissue elasticity and thickness of the flap, however, could not be ascertained in advance, indicating the limitations of the method.

Adolescent↗

PubMedDate not supplied

Computed tomography of malignant lymphoma involving the skull.

The CT findings in two patients with the unusual presentation of malignant lymphoma in the skull are described. The dominant CT findings were contrast enhanced large soft tissue masses without calcifications on both sides of the bone with very little or no changes in the bone itself. This characteristic CT appearance may be helpful to differentiate primary lymphoma of the skull from other bone tumors and osteomyelitis.

Adult↗

PubMed1995

Integrated life-sized solid model of bone and soft tissue: application for cleft lip and palate infants.

The recent development of three-dimensional computed tomography (3D-CT) and laser stereolithography has allowed the creation of life-sized skeletal models. The development of helical CT has enabled us to apply this method to very young children. However, skeletal models alone do not reveal the spatial relationship between soft tissue and bone in complicated craniofacial deformities. We have therefore developed a model that shows both soft and bony tissue by first using CT values that result in a model in which soft tissue is solid and bone is replaced by empty space. The space is then filled with plaster to represent the skeleton. This model also can provide baseline data for evaluating facial growth after surgical repair of clefts. Two infants with cleft lip and palate are presented to illustrate this method of creating an integrated solid model and its applications.

Bone and Bones↗

PubMed1998

Transaxial computer tomography of lower extremity lymphedema.

We examined retrospectively 11 patients with isolated unilateral lower limb lymphedema (clinical criteria confirmed by isotope lymphography) using computer tomography. In conjunction with earlier observations, the findings of soft tissue stranding, skin thickening, fat deposition in the epifascial compartment and perimuscular fascial thickening and edema relate to lymph stasis. This noninvasive and relatively simple imaging technique allows analysis of soft tissue changes in leg lymphedema and can be used to evaluate lymphatic insufficiency and its extent as well as document the response to treatment.

Adult↗

PubMed1993

Soft-tissue window to enhance visualization of entrapped osteocartilaginous fragments in the hip joint.

The thin-section computed tomographic (CT) scans of 11 patients with entrapped intra-articular fragments secondary to dislocation or fracture dislocation of the hip are studied. The effects of CT bone and soft-tissue contrast manipulation on the visibility of the intra-articular fragments are demonstrated in both patients and in vitro. When the mechanism of injury and clinical features raise the possibility of entrapped fragments, as in hip dislocation and fracture dislocation, special magnification and image-enhancement techniques are available for re-examining the acetabulum, especially when raw CT data are saved. Thus, index of suspicion and appropriate CT planning can ensure prompt diagnosis and treatment of entrapped intraarticular fragments in the hip joint.

Cartilage, Articular↗

PubMedDate not supplied

Computed tomography of osteogenic sarcoma of nasal cavity and paranasal sinuses.

Computed tomography was performed in four patients with osteogenic sarcoma of the nasal cavity and paranasal sinuses. In all cases CT demonstrated an abnormal soft tissue mass with associated aggressive bony destruction. In only one case were areas of calcification and new bone formation identified, allowing a preoperative diagnosis. The CT appearance of these four patients plus an additional four cases previously reported in the literature are reviewed.

Adolescent↗

PubMedDate not supplied

[Scintigraphy with thallium chloride in a case of clear cell sarcoma of the tendons and aponeurosis].

Clear cell sarcoma of the soft parts (CCSSP) is a rare and highly malignant tumor. This is a case report of a 31 years old woman who presented with a tumor in the internal face of left thigh. The tumor biopsy was suggestive of a possible malignant tumor of the peripheral nerve sheath (malignant schwannoma). Biochemical analyses, computed tomography and magnetic resonance were performed and reported a sarcoma of soft parts (CCSSP) without abnormal inguinal lymph nodes. With this diagnostic suspicion, the patient was sent to the Nuclear Medicine Service of our center where a 201Thallium scintigraphy study was performed. In this study, it showed the primary tumor together with a hot spot in the homolateral inguinal region, suggestive of the presence of a metastastic lymph node. This finding would change the surgical attitude in the patient, including inguinal lymphadenectomy. The post-surgical histological study confirmed a clear cell sarcoma of soft parts (CCSSP) with a metastatic inguinal lymph node.

Adult↗