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PubMed1986

Computed tomography of extraosseous ganglia.

Computed tomography (CT) was performed in six patients with painful soft-tissue masses where sarcoma was suspected. Incisional or excisional biopsy proved all to be extraosseous ganglia. CT delineated the anatomic relationships of the masses. The CT density of four of the ganglia was 18 Hounsfield Units (HU), consistent with that of fluid-filled lesions. Contrast medium did not enhance the lesions on CT. Angiography was performed in four cases and demonstrated hypovascular masses with no vessel displacement. Plain radiographs and technetium bone scintigrams were nonspecific. CT was the best preoperative confirmation of the diagnosis of benign extraosseous ganglia and the best method of localizing the lesions with respect to surrounding bone and soft tissues.

Adolescent↗

PubMed1982

Computed tomography of sacral and presacral lesions.

Forty-two patients with various sacral and presacral lesions were examined by computed tomography (CT). CT was sensitive in detecting intraosseous neoplasms and presacral soft tissue masses and in seven cases identified lesions not visible on plain films. The total extent of each lesion was readily determined using CT. However, CT is diagnostically nonspecific and differentiation between primary and secondary tumors of the sacrum in generally not possible from the CT appearance alone. CT is also of considerable use in the evaluation of several non-neoplastic conditions of the sacrum, including spinal dysraphism, anterior and internal meningocele and trauma.

Adolescent↗

PubMed2003

Unusual clinical manifestation of virus-associated hemophagocytic syndrome.

A 22-year-old man presented with bilateral painless cervical lymphadenomegaly, difficulties in nasal breathing and bilateral conductive hearing loss. Rhinoscopy and computer tomography disclosed mucosal polyps in the nasal cavity and a polypoid soft mass almost completely filling the whole nasal cavity and the paranasal sinuses. Thoracic and abdominal computer tomography showed mild hepatosplenomegaly and a solitary round lesion in the right lung. No fever or abnormal laboratory parameters were detected. The biopsy from the nasal polypoid lesions and from the cervical lymph nodes showed extensive proliferation of histologically benign erythrophagocytic histiocytes. The diagnosis of virus (Epstein-Barr virus)-associated hemophagocytic histiocytosis was confirmed by immunohistochemical reactions, by polymerase chain reaction, and by Epstein-Barr-Encodes (Early)-RNA in situ hybridization. This case illustrates an unusual clinical manifestation of virus-associated hemophagocytic histiocytosis presenting as mucosal polyps of the upper respiratory tract.

Adult↗

PubMed1997

Orbital immunocytoma simulating Hodgkin's disease by mimicking Hodgkin- and Reed-Sternberg-like cells.

PURPOSE: The present case report describes primary orbital immunocytoma (IgM-kappa) mimicking Hodgkin's disease of the diffuse, lymphocyte predominance type by expressing Hodgkin simulating cells as well as Reed-Sternberg simulating cells (both: H-RS cells). PATIENTS AND METHODS: The patient (87a; male) was admitted to hospital with increasing left upper eyelid protrusion. Computed tomography revealed an unspecific accumulation of soft tissue within the orbit. A biopsy was taken. Light microscopical sections were stained with PAS, Giemsa and haematoxylin-eosin. Immunohistochemistry was performed following standard procedures. RESULTS: By means of light microscopy, Hodgkin's disease of the diffuse, lymphocyte predominance type was indicated. This initial diagnosis was mainly based on morphological criteria, e.g. the presence of H-RS-like cells. Since staging work-up produced no evidence of systemic disease, immunohistochemistry was performed. It revealed that the misleading cells were H-RS simulating cells. Finally, the diagnosis made was that of immunocytoma (IgM-kappa); stage I EA. CONCLUSION: The diagnosis of Hodgkin's disease of the diffuse, lymphocyte predominance type is normally based on morphological criteria. However, in very rare cases immunocytomas simulate this variant of Hodgkin's disease by expressing misleading H-RS simulating cells. Thus, immunohistochemical investigations should generally be included in the criteria for the diagnosis of Hodgkin's disease of the diffuse, lymphocyte predominance type. As far as we are aware, primary immunocytoma mimicking this variant of Hodgkin's disease within the orbit has never been reported.

Aged↗

PubMed2003

An investigation of entrance surface dose calculations for diagnostic radiology using Monte Carlo simulations and radiotherapy dosimetry formalisms.

Our aim in this work was to investigate the methodology used in the determination of the entrance surface dose (ESD) in diagnostic radiology. In kV x-rays for low-energy photons (tube potential up to 160 kV, HVL: 1-8 mm Al), the ESD is based on the use of the ratio of mass-energy absorption coefficients and backscatter factors. A full simulation of the photon and electron transport in a kilovoltage x-ray unit, using the Monte Carlo code BEAM/EGS4, was performed to obtain an accurate beam phase space for use in dose calculation. The modelled phase space was experimentally validated for the beam qualities (measured HVL: 3.3 mm Al-2.2 mm Cu) and showed good agreement between calculated and measured HVLs, air kerma and relative dose distributions. We have computed the conversion factors from air kerma to water or soft tissue absorbed dose at the surface of a phantom for beam qualities (HVL: 3.3-8.35 mm Al). The same model was also used to calculate the ESD in water and in soft tissue for the low-energy photon range considered. The results show that the numerical differences between the air kerma and the water kerma based backscatter factors are insignificant. The same conclusion was reached for the (mu(en)/rho) ratios, for soft tissue to air, evaluated using either the primary photon spectra or the spectra at the surface of a phantom. Furthermore, the good agreement obtained for the computation of the conversion factors with a full BEAM/EGS4 model confirms the previous studies which are based on different sources for the spectral distribution and different beam geometries (pencil beam or point source assumptions). On the other hand, the ESD in water or soft tissue is well described either with the B(air) or the B(w) formalism. Conversion factors from air kerma to ESD in these media are proposed in this work for several beam qualities in diagnostic radiology.

Biophysical Phenomena↗

PubMedDate not supplied

Diagnostic accuracy in sinus fungus balls: CT scan and operative findings.

A fungus ball may be characterized by its radiologic and operative gross findings. Computed tomography (CT) revealed a rim of soft tissue attenuation of variable thickening along the bony walls of the isolated paranasal sinus, or mottled hyperdense foci of variable size. A small amount of friable muddy mass surrounded by purulent secretions or dirty brown clay-like materials provide highly pathognomonic findings. However, these characteristics may induce clinical misdiagnosis. During the last four years we experienced 11 cases of chronic paranasal sinusitis in which pathologic examination failed to confirm fungal hyphae, despite clinical suspicion of a fungus ball based on operative or CT findings. During the same period, we also experienced another 52 patients who were diagnosed with fungus ball at pathologic examination. To evaluate the diagnostic accuracy of CT scans and operative gross findings in sinus fungus balls, we reviewed the medical records of these 63 patients and also reviewed CT scans and operative records of another 1127 patients who received endoscopic sinus surgery for chronic rhinosinusitis. The sensitivity of CT evaluation was 62%, and specificity was 99%. The false-positive and false-negative rate were 22% and 2%, respectively. With regard to operative findings, such as clay-like inspissated mucus, the sensitivity, specificity, and predictive value positive rate were 100%, 99%, and 83%, respectively. To make a diagnosis of fungus ball, a high index of suspicion is necessary and a pathologic confirmation is mandatory.

Diagnosis, Differential↗

PubMed1997

A computer-interfaced vertometer system for contact lenses.

BACKGROUND: The conventional vertometer (lensometer) is difficult to use for accurate measurement of contact lenses whose back vertex power (BVP) varies across the optic zone. BVPs of multifocal rigid and soft contact lenses have previously been measured using a conventional vertometer incorporating the Scheiner principle, which makes use of two light paths equidistant from the center of the lens. METHODS: We have developed a computer-based vertometer system based on the Scheiner principle which can be used to produce a profile of BVPs across rigid and soft contact lenses. A computer interface to the vertometer allows rapid acquisition of readings and software-based ray tracing derives in-air dioptric power readings across the optic zone at specific ray heights. RESULTS: Results are presented for soft and rigid, and spherical and aspheric surface contact lenses. CONCLUSIONS: The system improves the measurement resolution of a standard vertometer and shows an acceptable level of precision and accuracy for most applications.

Contact Lenses↗

PubMedDate not supplied

Optimal radiologic imaging of soft tissue sarcomas.

Radiologic evaluation of the patient with soft tissue sarcoma may include conventional radiography, scintigraphy, ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. The radiologist also plays a critical role in the evaluation of the patient with soft tissue sarcoma by guiding and performing aspiration biopsies. This review discusses the use of radiological techniques to evaluate the primary lesion and to detect recurrences. In adults, soft tissue sarcoma most commonly occurs in the extremities, and this review emphasizes the role of MR imaging in the pre- and post-treatment evaluation of extremity soft tissue sarcomas. The role of imaging studies in the evaluation of soft tissue sarcomas in the abdomen, thorax, and the head and neck region is also discussed.

Biopsy, Needle↗

PubMed2000

Accuracy of muscle moment arms estimated from MRI-based musculoskeletal models of the lower extremity.

OBJECTIVE: Biomechanical models that compute the lengths and moment arms of soft tissues are broadly applicable to the treatment of movement abnormalities and the planning of orthopaedic surgical procedures. The goals of this study were to: (i) develop methods to construct subject-specific biomechanical models from magnetic resonance (MR) images, (ii) create models of three lower-extremity cadaveric specimens, and (iii) quantify the accuracy of muscle-tendon lengths and moment arms estimated using these models. MATERIALS AND METHODS: Models describing the paths of the medial hamstrings and psoas muscles for a wide range of body positions were developed from MR images in one joint configuration by defining kinematic models of the hip and knee, and by specifying "wrapping surfaces" that simulate interactions between the muscles and underlying structures. Our methods for constructing these models were evaluated by comparing hip and knee flexion moment arms estimated from models of three specimens to the moment arms determined experimentally on the same specimens. Because a muscle's moment arm determines its change in length with joint rotation, these comparisons also tested the accuracy with which the models could estimate muscle-tendon lengths over a range of hip and knee motions. RESULTS: Errors in the moment arms calculated with the models, averaged over functional ranges of hip and knee flexion, were less than 4 mm (within 10% of experimental values). CONCLUSION: The combination of MR imaging and graphics-based musculoskeletal modeling provides an accurate and efficient means of estimating muscle-tendon lengths and moment arms in vivo.

Biomechanical Phenomena↗

PubMed2002

Gigantic thymolipoma.

A 48-year-old woman with an abnormal shadow in chest radiography during an annual physical examination was found by chest computed tomography to have a large fatty mass lesion found to be diagnosed as a gigantic lipoma. Histopathological diagnosis was found to be benign thymolipoma consisting of mature fatty tissue and hyperplastic thymic tissue structures with Hassall,s corpuscles. Although the diagnosis is supported by imaging studies that demonstrate fat and soft tissue within the tumor, variations occur in computed tomography appearance. We suggest that surgical excision be considered when a gigantic intrathoracic lipomatous mass is in scanning as in this case.

Female↗

PubMed2006

[Multimodalities imaging for target volume definition in radiotherapy].

Modern radiotherapy delivery nowadays relies on tridimensional, conformal techniques. The aim is to better target the tumor while decreasing the dose administered to surrounding normal tissues. Gold standard imaging modality remains computed-tomography (CT) scanner. However, the intrinsic lack of contrast between soft tissues leads to high variabilities in target definition. The risks are : a geographical miss with tumor underirradiation on the one hand, and a tumor overestimation with undue normal tissues irradiation on the other hand. Alternative imaging modalities like magnetic resonance imaging and functional positron emission tomography could theoretically overcome the lack of soft tissues contrast of CT. However, the fusion of the different imaging modalities images requires the use of sophisticated computer algorithms. We will briefly review them. We will then review the different clinical results reported with multi-modalities imaging for tumors of the head, neck, lung, esophagus, cervix and lymphomas. Finally, we will briefly give practical recommendations for multi-modality imaging in radiotherapy treatment planning process.

Algorithms↗

PubMed2005

Aerodynamic effects of inferior turbinate reduction: computational fluid dynamics simulation.

OBJECTIVE: To investigate the aerodynamic consequences of conservative unilateral inferior turbinate reduction using computational fluid dynamics methods to accomplish detailed nasal airflow simulations. DESIGN: A high-resolution, finite-element mesh of the nasal airway was constructed from magnetic resonance imaging data of a healthy man. Steady-state, inspiratory airflow simulations were conducted at 15 L/min using the techniques of computational fluid dynamics. INTERVENTION: Circumferential removal of 2 mm of soft tissue bulk along the length of the left inferior turbinate was modeled. MAIN OUTCOME MEASURES: Nasal airflow distribution and pressure profiles were computed before and after simulated left inferior turbinate reduction. RESULTS: Simulated inferior turbinate reduction resulted in a broad reduction of pressure along the nasal airway, including the regions distant from the inferior turbinate vicinity. In contrast, relative airflow changes were regional: airflow was minimally affected in the valve region, increased in the lower portion of the middle and posterior nose, and decreased dorsally. CONCLUSION: Use of computational fluid dynamics methods should help elucidate the aerodynamic significance of specific surgical interventions and refine surgical approaches to the nasal airway.

Computer Simulation↗

PubMed2002

Bilateral multiple cervical root avulsions without skeletal or ligamentous damage resulting from blast injury: case report.

OBJECTIVE AND IMPORTANCE: We describe a unique case of multiple bilateral cervical root injuries without ligamentous or bony injury secondary to a sandblast accident. CLINICAL PRESENTATION: A 19-year-old man sustained a sandblast injury to his face, neck, chest, and upper extremities, with immediate loss of motor and sensory function occurring in both of his upper extremities. Cervical spine x-rays, computed tomography, and magnetic resonance imaging demonstrated no fracture, soft tissue abnormality, or malalignment. The restriction of deficits to the patient's upper extremities suggested a central cervical spinal cord injury, bilateral brachial injuries, or a conversion disorder. INTERVENTION: Cervical computed tomographic myelography revealed multiple bilateral nerve root injuries. CONCLUSION: This case report is unique in the literature in that it describes a patient with multiple cervical nerve root injuries secondary to sandblast injury without ligamentous or bony injury. Although magnetic resonance imaging remains the diagnostic modality of choice in patients with acute spinal cord injury, it is deficient in demonstrating cervical root injury in the acute setting. In this setting, computed tomographic myelography is superior.

Adult↗

PubMed2006

Young's modulus reconstruction of vulnerable atherosclerotic plaque components using deformable curves.

Rupture, with subsequent thrombosis, of thin-cap fibroatheromas (TCFAs) is a major cause of myocardial infarction. A TCFA has two main components: these are a large, soft lipid pool and a thin, stiff fibrous cap covering it. Quantification of their morphology and stiffness is essential for monitoring atherosclerosis and quantifying the effect of plaque-stabilizing pharmaceutical treatment. To accomplish this, we have developed a model-based Young's modulus reconstruction method. From a plaque strain elastogram, measured with an intravascular ultrasound catheter, it reconstructs a Young's modulus image of the plaque. To this end, a minimization algorithm automatically varies the morphology and stiffness parameters of a TCFA computer model, until the corresponding computer-simulated strain elastogram resembles the measured strain elastogram. The morphology parameters of the model are the control-points of two deformable Bézier curves; one curve delineates the distal border of the lipid pool region, the other the distal border of the cap region. These component regions are assumed to be homogeneous and their stiffness is characterized by a Young's modulus. Reconstructions from strain elastograms that were 1. simulated using a histology-derived computer TCFA, 2. measured from a physical phantom with a soft lipid pool, and 3. simulated with a computer TCFA, where the complexity of its plaque component borders was increased, demonstrated the superior reconstruction/delineation behavior of this method, compared with a previously developed circular reconstruction method that used only circles for border delineation. Consequently, this method may become a valuable tool for the quantification of both the morphology and stiffness of vulnerable atherosclerotic plaque components.

Algorithms↗

PubMed1997

[Imaging of the temporomandibular joint].

A large number of imaging techniques are available nowadays to visualise the temporomandibular joint and surrounding structures. It is important that osseous structures as well as soft tissue can be shown. Transcranial images, conventional tomography, panoramic radiography and computed tomography (CT) are more suitable for viewing the osseous structures. The best techniques to evaluate the soft tissues are arthrography and especially magnetic resonance imaging (MR). The panoramic radiography is the technique of choice in the general practice and provides adequate screening images of the temporomandibular joints, mandible, maxilla, teeth and surrounding tissues. When the joint is suspected of developmental anomalies, neoplastic conditions or a condylar trauma, CT-images are necessary to depict the bony abnormalities. CT has a poor reliability in imaging the disk. For this reason, disk displacements of the temporomandibular joint are best shown with MR, although the clinician should be very restrictive in using MR-images. They are very expensive and are only useful to confirm an uncertain diagnosis, or if disc surgery is the treatment of choice. The anamnesis and the clinical investigation are still the most important elements in diagnosing craniomandibular dysfunction.

Arthrography↗

PubMed2006

Application of inkjet printing to tissue engineering.

Recent advances in organ printing technology for applications relating to medical interventions and organ replacement are described. Organ printing refers to the placement of various cell types into a soft scaffold fabricated according to a computer-aided design template using a single device. Computer aided scaffold topology design has recently gained attention as a viable option to achieve function and mass transport requirements within tissue engineering scaffolds. An exciting advance pioneered in our laboratory is that of simultaneous printing of cells and biomaterials, which allows precise placement of cells and proteins within 3-D hydrogel structures. This advance raises the possibility of spatially controlling not only the scaffold structure, but also the type of tissue that can be grown within the scaffold and the thickness of the tissue as capillaries and vessels could be constructed within the scaffolds. Here we summarize recent advances in printing cells and materials using the same device.

Animals↗

PubMedDate not supplied

Hepatic angiomyolipoma.

The imaging and pathological appearances of a hepatic angiomyolipoma are presented. On ultrasound (US), the mass was well-defined and echogenic. On computed tomography (CT), the lesion appeared of soft tissue density with peripheral foci of lower density. The case illustrates the difficulty of detecting the fatty content of a tumor by CT when the fatty content represents only a small portion of the lesion. Fine-needle aspiration (FNA) cytology and needle biopsy did not yield diagnostic material, and the tumor was resected.

Adult↗

PubMed2000

Primary lymphoma of bone originating in a rib.

Malignant lymphoma originating in the bone is rare and is now recognized as being an independent clinicopathologic entity known as primary lymphoma of bone. A 60-year-old man complaining of right chest and back pain consulted our hospital for further examination. Chest X-ray and computed tomogram revealed osteolysis and a surrounding soft tissue mass in the sixth right rib. An ultrasonically-guided needle biopsy of the tumor was performed, and histologic examination indicated the dense proliferation of similar-sized atypical cells with nucleoli and an irregular nuclear border. A diagnosis of diffuse, medium-sized non-Hodgkin's lymphoma, B-cell type was made. En block resection of the tumor and chest wall was performed. Macroscopically, the tumor measured 7.5 x 4.8 x 3.0 cm in diameter, and the histologic findings were similar to those of the preoperative needle biopsy. Unfortunately, postoperative treatment with radiation therapy and chemotherapy was ultimately unsuccessful, and a local recurrence and metastatic lesions appeared in the stomach and para-aortic abdominal lymph nodes 7 months after the first symptom appeared. The patient died 3 months later. Surgery was chosen as the initial therapy as it was considered that a rib resection would not result in serious respiratory compromise and the complete resection of the tumor would be superior to radiation therapy for local control. Some authors have reported that the surgical resection of a primary lymphoma of the bone originating in a rib can yield a good prognosis. However, it is a systemic disease and a more effective therapeutic strategy should be developed.

Bone Neoplasms↗