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PubMed1997

Surgical prediction reliability: a comparison of two computer software systems.

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs. The presurgical and postsurgical cephalometric radiographs of 28 patients were digitized onto each computer program. A customized analysis was created to determine the amount of surgical movement, as well as to compare the actual postsurgical soft tissue profile with the computer-generated prediction. The results demonstrated that, on the average, the predictions were not significantly different from the actual postsurgical profile changes. While each program generated statistically similar prediction results, marked variability was noted. There was no significant difference found in the prediction errors between patients who had one-jaw surgery and those who had two-jaw surgery. This study found that a linear relationship existed between the surgical movement and the prediction error. In general, the greater the magnitude of the surgical movement, the larger the prediction error.

Adolescent↗

PubMed2003

Three-dimensional simulation and prediction of craniofacial surgery.

The treatment of patients with complex facial deformities is one of the most challenging multidisciplinary tasks in plastic surgery. Due to advancements in medical technology and surgical techniques in the last 20 years correction of severe malformations has become possible and is performed by highly specialized teams frequently in a single operation. Recent developments in three-dimensional (3-D) imaging techniques have already greatly facilitated diagnosis of complex craniofacial deformities. Computer-based simulation methods for surgical procedures that are based on imaging data have the potential to improve surgical treatment by providing the ability to perform 'virtual surgery' preoperatively and thus reduce patient risk and morbidity intraoperatively. A method is presented for interactive computer-assisted craniofacial plastic surgery planning and visualization, especially simulation of soft tissue changes using an experimental Craniofacial Surgery Planner. The system computes non-linear soft-tissue deformation because of bone realignment. It is capable of simulating bone cutting and bone realignment with integrated interactive collision detection. Furthermore, soft-tissue deformation and cutting due to surgical instruments can be visualized. Simulation processes are based on an individual patient's preoperative 3-D computed tomography and on a 3-D, photo-realistic model of the patient's preoperative appearance obtained by a laser range scanner. Very fast and robust prediction of non-linear soft-tissue deformation is computed by optimizing a non-linear cost function.

Computer Simulation↗

PubMed2004

Modality independent elastography (MIE): a new approach to elasticity imaging.

The correlation between tissue stiffness and health is an accepted form of organ disease assessment. As a result, there has been a significant amount of interest in developing methods to image elasticity parameters (i.e., elastography). The modality independent elastography (MIE) method combines a nonlinear optimization framework, computer models of soft-tissue deformation, and standard measures of image similarity to reconstruct elastic property distributions within soft tissue. In this paper, simulation results demonstrate successful elasticity image reconstructions in breast cross-sectional images acquired from magnetic resonance (MR) imaging. Results from phantom experiments illustrate its modality independence by reconstructing elasticity images of the same phantom in both MR and computed tomographic imaging units. Additional results regarding the performance of a new multigrid strategy to MIE and the implementation of a parallel architecture are also presented.

Algorithms↗

PubMed1982

CT of calcified renal masses.

The ability to evaluate the composition and to precisely locate calcifications within renal masses resulted in more accurate evaluation of 21 calcified renal masses by computed tomography than by standard radiographic techniques. Of 11 solid tumors, computed tomography demonstrated a soft-tissue mass extending beyond the calcification in nine cases of renal cell carcinoma. Of 10 benign cystic lesions, all six lesions characterized by a uniform water-density center, calcification confined to the wall, and no detectable soft-tissue mass were benign cysts. Three additional cystic lesions (xanthogranulomatous pyelonephritis, multilocular cystic nephroma, and a cyst containing calcified debris) were believed to represent benign lesions prospectively due to the absence of a soft-tissue mass. Only peripherally calcified lesions with a central attenuation higher than accepted for benign cysts were indeterminate by computed tomography. The significance of the computed tomographic findings in terms of malignant potential and patient management is discussed.

Adenocarcinoma↗

PubMedDate not supplied

Biomechanics of soft tissues.

Recent developments in Computer-Integrated and Robot-Aided Surgery (in particular, the emergence of automatic surgical tools and robots (as well as advances in Virtual Reality techniques, call for closer examination of the mechanical properties of very soft tissues (such as brain, liver, kidney, etc.). Moreover, internal organs are very susceptible to trauma. In order to protect them properly against car crash and other impact consequences we need to be able to predict the organ deformation. Such prediction can be achieved by proper mathematical modelling followed by a computer simulation. The ultimate goal of our research into the biomechanics of these tissues is development of corresponding, realistic mathematical models. This paper contains experimental results of in vitro, uniaxial, unconfined compression of swine brain tissue obtained by the author in Mechanical Engineering Laboratory, Japan, and discusses liver and kidney in vivo compression experiments conducted in Highway Safety Research Institute and the Medical Centre of The University of Michigan. The stress-strain curves for investigated tissues are concave upward for all compression rates containing no linear portion from which a meaningful elastic modulus might be determined. The tissue response stiffened as the loading speed increased, indicating a strong stress (strain rate dependence. As the step in the direction towards realistic computer simulation of injuries and surgical procedures, this paper presents two mathematical representations of brain, liver and kidney tissue stiffness. Biphasic and single-phase models are discussed. The biphasic model is shown to be inappropriate due to its inability to account for strong stress-strain relationship. Agreement between the proposed single-phase models and experiment is good for compression levels reaching 30% and for loading velocities varying over five orders of magnitude. Presented mathematical models can find applications in computer and robot assisted surgery, e.g. the realistic simulation of surgical procedures (including virtual reality), control systems of surgical robots, and non-rigid registration, as well as ergonomic design for injury prevention.

Animals↗

PubMed1994

A semi-automated micro-method for the histological assessment of fat embolism.

A method of quantitatively determining the volume of fat emboli in a tissue using an image analysis system (I.B.A.S.) was developed. This procedure is an interactive, semi-automated tool allowing the quick and accurate gathering of large quantities of data from sections of different tissue samples stained by osmium tetroxide. The development of this procedure was aimed at producing a system which is reliable, reproducible and semi-automated thereby enabling epidemiological and serial studies to be made of a large number of histological sections from different tissues. The system was tested in a study of tissue sections from a series of fatalities from an aircraft crash in an attempt at correlating the incidence of fat emboli with the presence of multiple fractures and soft tissue injuries, the correlation to be made being between the quantitative presence of fat emboli and the extent and severity of injuries suffered.

Accidents, Aviation↗

PubMed1986

[Computed tomography in imaging in maxillofacial surgery].

The improved definition and good visualization of soft tissues provided by high resolution computed tomography imaging greatly exceeds results of conventional tomography investigations. It is irreplaceable for tumoral lesions, particularly of the facial region, when not only the tumor but its degree of extension are perfectly identified. In orbital injuries it is the only imaging procedure capable of visualizing the orbital contents and its relation with the fracture line.

Facial Neoplasms↗

PubMed2001

Humeral hydatid cyst complicated with extraosseous involvement: a case of unusual location of echinococcosis.

Hydatid disease is a parasitic disease most commonly caused by Echinococcus granulosus that seldom involves the skeleton and is still common in the countries of the temperate zones. We present an extremely rare case report of a young patient with humeral hydatid disease complicated with extraosseous involvement. Plain film of the left humerus demonstrated distortion of the axis, regional expansion of the humeral shaft with minimal thinning areas of the cortex. Additionally, numerous radiolucent areas of the humeral shaft were observed especially at the distal part of the bone. No calcification of the soft tissues was noticed. Computed tomography examination showed significant destruction of the trabecular bone of the humeral head and polycystic appearance of the bone marrow with regional calcifications into the lumen. Additionally, a large cystic lesion between medial and lateral head of the triceps muscle with some foci of calcifications were observed. Magnetic resonance imaging revealed the multiocular nature of the lesion into the humeral lumen with a cystic lesion involving the soft tissues of the upper arm. The cyst showed contrast enhancement at the pericyst capsule of the cyst after Gadolinium-DTPA administration.

Adolescent↗

PubMed2000

Development and application of a virtual environment for reconstructive surgery.

OBJECTIVE: This paper details the development and application of a Virtual Environment for Reconstructive Surgery (VERS). It addresses the technical and user-interface challenges in developing such a system, and the lessons learned during application of the system in the case of a 17-year-old boy with a severe facial defect arising from the removal of a soft-tissue sarcoma. MATERIALS AND METHODS: Computed tomography (CT) scans were segmented into bone and soft-tissue classifications using traditional and novel algorithms, a surface mesh was generated, and imaging artifacts were removed, yielding a mesh suitable for visualization. This patient-specific mesh was then used in a virtual environment by the surgeons for preoperative visualization of the defect, planning of the surgery, and production of a custom surgical template to aid in repairing the defect. RESULTS: This system was successfully used to plan the surgery of the patient and to produce a custom, patient-specific template that was used to harvest bone from a donor site in order to reconstruct the defect. CONCLUSION: Despite technical challenges, virtual-environment surgical planning is useful as a clinical tool for preoperative visualization, cephalometric analysis, and surgical intervention. It can provide a more precise surgical result than would otherwise be realized using traditional methods.

Adolescent↗

PubMed2006

Genital beta2-microglobulin amyloidoma in a long-term dialysis patient.

We present the case of a 58-year-old Japanese woman with a huge amyloid tumor in the genital region. Hemodialysis therapy was started for renal failure secondary to polycystic kidney disease in 1974. From 1989 to 1991, carpal tunnel decompression was performed surgically, and beta(2)-microglobulin (beta2MG)-amyloid deposition was found in the wrists. She was hospitalized at our institute for evaluation of lower-abdominal fullness and lower-extremity edema in March 2003. Magnetic resonance imaging showed a huge mass measuring 9.0 x 6.0 x 5.0 cm sandwiched between the vagina and rectum. The mass was hypointense compared with adjacent muscle on T2-weighted images. Computed tomography showed soft-tissue density accompanied by diffuse calcification. A biopsy specimen of the mass obtained by using a transvaginal approach showed material that was positive for beta2MG-amyloid immunohistologically. When patients on long-term dialysis therapy develop a genital mass with low-signal intensity on T2-weighted images by magnetic resonance imaging and diffuse calcification by computed tomography, beta2MG-amyloidoma should be considered as a differential diagnosis.

Amyloidosis↗

PubMed1987

Angelchik antireflux device: computed tomography appearance.

The Angelchik antireflux prosthesis is a silicon gel-filled, doughnut-shaped device with a tantalum tie strap that wraps around the gastroesophageal junction after reduction of a hiatal hernia. If dislodged, this prosthesis may produce a confusing picture on computed tomography, as it is of soft tissue density and may mimic a mass lesion. The computed tomography appearance of a normally placed prosthesis is demonstrated, and a case of prosthesis dislodgment diagnosed by computed tomography is reported.

Adult↗

PubMed1996

Resolution of a soft-tissue sarcoma in a patient with rheumatoid arthritis after discontinuation of azathioprine therapy.

An 85-year-old woman with rheumatoid arthritis that was treated with azathioprine presented with a posterior thoracic soft-tissue mass. A computed tomographic scan demonstrated a large mass in the chest wall that extended into the pleural space and several pulmonary nodules that were consistent with metastatic disease. A fine-needle biopsy was performed, and a morphologic diagnosis of sarcoma was made. As the patient was relatively asymptomatic and the lesion was inaccessible to a surgical procedure, no therapy was recommended. Therapy with azathioprine was discontinued. One year later, the mass had resolved. To our knowledge, this is the first reported case of a soft-tissue sarcoma complicating azathioprine treatment of rheumatoid arthritis.

Aged↗

PubMed1998

Effect of early orthopedic intervention on hemifacial microsomia patients: an approach to a cooperative evaluation of treatment results.

The purpose of the present study was to analyze the effects of early orthopedic intervention in patients with hemifacial microsomia, clinically as well as radiologically, by computed tomographic examination to assess soft and hard tissue temporomandibular joint changes. Five patients, one with mandibular dysostosis, one with otomandibular dysostosis, two with Goldenhar syndrome, and one with a surgically revised fibroma of the right mandible that was reconstructed by a costochondral graft, were treated by means of an activator functional appliance. During functional appliance treatment, all patients showed improvement of function and occlusion, and facial asymmetry was reduced. Spiral computed tomographic examination before and during treatment provided data on the bony and muscular deficiencies. The volume and density of the lateral pterygoid muscle was measured with the standard computed tomography software. Evaluation of soft and hard tissue conditions before treatment has shown that the most important factor "lack of soft tissues" can be compensated by excellent cooperation during functional therapy. Pretreatment volume of the affected lateral pterygoid muscle in all patients was significantly smaller than on the unaffected side. In three patients, volume measurements between 4 and 8 years demonstrated that the lateral pterygoid muscle on the affected side had a third, less than a third, and a fifth of the volume of the unaffected side. Although increase, stability, and decrease of the ratio of left and right condylar dimension, muscular volume, and density were found, long-term prognosis cannot be given in the cases with extreme muscular deficiencies after cessation of growth. Prepubertal orthopedic treatment success is a desirable and feasible presurgical or nonsurgical treatment goal for the interdisciplinary team approach. From a study of the pathologic, we learn much about the normal.

Child↗

PubMed1991

Cancer surveillance of Veterans in Massachusetts, USA, 1982-1988.

This surveillance study is a follow-up to previous findings of elevated soft tissue sarcoma mortality in Massachusetts Vietnam veterans compared to other veterans. The roster of veterans was compiled from Massachusetts residents who received a state bonus for military service in the period 1958-1973. This computerized list was linked to the central files of the Massachusetts Cancer Registry and cases diagnosed between 1982 and 1988 were identified. Odds ratios (ORs) for several cancer sites were computed; only that for soft tissue sarcoma incidence was significantly elevated in Vietnam veterans compared to other veterans (OR = 3.08; 95% confidence interval: (CI) 1.07-8.73). Kaposi's sarcoma cases who were also AIDS patients were excluded from the analysis. Non-Hodgkin's lymphoma was also investigated but was not significantly elevated in these surveillance data. Sources of bias are discussed and recommendations for continued surveillance and follow-up studies are made.

Adult↗

PubMed1985

Bimaxillary protrusion in the Caucasian: a cephalometric study of the morphological features.

The skeletal morphology of bimaxillary dental protrusion has been investigated in a comparative cephalometric study. Because this is considered a subset of Class I malocclusions, the null hypothesis is that there should be no significant skeletal differences between this group and a Class I control group. There were 30 Caucasians in each group with no bias for age and sex differences between them. Eighteen radiographic landmarks were identified from which 33 skeletal, dental and soft tissue parameters were computed. The bimaxillary group had an average interincisal angle of 115 degrees versus the controls 135 degrees, and showed the following morphological features which persisted over a 5-year growth period: A shorter posterior cranial base. A longer and more prognathic maxilla. Similar mandibular dimensions and prognathism. A mild Class II skeletal pattern. A smaller upper and posterior face height. Diverging facial planes. A procumbent soft tissue profile with a low lip line. These findings indicate that there is a distinctive difference between the underlying skeletal patterns found in the two groups.

Adolescent↗

PubMed1988

Lipoma and liposarcoma of the parotid gland: high-resolution preoperative imaging diagnosis.

Over the past 7 years, nine fatty tumors within the parotid gland have been managed (eight lipomas, one liposarcoma). High-resolution computed tomography examination was carried out in all cases; with correct preoperative diagnosis recorded each time. The computed tomography imaging characteristics of lipoma, liposarcoma, and the differential diagnosis from other fat density lesions, such as a fatty infiltration, appear quite specific. The liposarcoma and six of the lipomas were resected at formal parotidectomy with facial nerve preservation. Two patients with small intraglandular lipomas have elected to undergo long-term clinical and imaging observation. Our experience indicates that high-resolution, soft-tissue imaging with computed tomography and magnetic resonance imaging permits consistent preoperative fatty tumor diagnosis. This imaging input facilitates rational treatment decision-making.

Absorptiometry, Photon↗

PubMed2006

Can 16-detector multislice CT exclude skeletal lesions during tumour staging? Implications for the cancer patient.

Current imaging guidelines recommend that many cancer patients undergo soft-tissue staging by computed tomography (CT) whilst the bones are imaged by skeletal scintigraphy (bone scan). New CT technology has now made it feasible, for the first time, to perform a detailed whole-body skeletal CT. This advancement could save patients from having to undergo duplicate investigations. Forty-three patients with known malignancy were investigated for bone metastasis using skeletal scintigraphy and 16-detector multislice CT. Both studies were performed within six weeks of each other. Whole-body images were taken 4 h after injection of 500 Mbq (99m)Tc-MDP using a gamma camera. CT was performed on a 16-detector multislice CT machine from the vertex to the knee. The examinations were reported independently and discordant results were compared at follow-up. Statistical equivalence between the two techniques was tested using the Newcombe-Wilson method within the pre-specified equivalence limits of +/-20%. Scintigraphy detected bone metastases in 14/43 and CT in 13/43 patients. There were seven discordances; four cases were positive on scintigraphy, but negative on CT; three cases were positive on CT and negative on scintigraphy. There was equivalence between scintigraphy and CT in detecting bone metastases within +/-19% equivalence limits. Patients who have undergone full whole-body staging on 16-detector CT may not need additional skeletal scintigraphy. This should shorten the cancer patient's diagnostic pathway.

Adult↗

PubMed1996

Alveolar soft part sarcoma metastatic to the breast.

Metastasis to the breast is uncommon, with an incidence of 0.5-3%. Alveolar soft part sarcoma is rare, accounting for < 1% of malignant soft tissue tumors, which are themselves unusual. Excluding contralateral breast and hematologic malignant disease, the primary lesion in most cases of metastasis to the breast is melanoma, small cell carcinoma of the lung, or ovarian carcinoma, although rhabdomyosarcoma is the most common primary tumor in children. We describe a 26-year-old woman with no history of malignant disease who presented with two masses in the right breast that clinical evaluations and ultrasonography indicated were fibroadenomas. Pathological studies after excisional biopsy, however, indicated alveolar soft part sarcoma. Subsequent computed tomography showed the primary tumor in the anterior left thigh and multiple bilateral lung metastases. Because of the presence of distant metastases, the patient was treated with chemotherapy.

Adult↗