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PubMed2005

Volume rendering in the presence of partial volume effects.

In tomographic imagery, partial volume effects (PVEs) cause several artifacts in volume renditions. In X-ray computed tomography (CT), for example, soft-tissue-like pseudo structures appear in bone-to-air and bone-to-fat interfaces. Further, skin, which is identical to soft tissue in terms of CT number, obscures the rendition of the latter. The purpose of this paper is to demonstrate these phenomena and to provide effective solutions that yield significantly improved renditions. We introduce two methods that detect and classify voxels with PVE in X-ray CT. Further, a method is described to automatically peel skin so that PVE-resolved renditions of bone and soft tissue reveal considerably more detail. In the first method to address PVE, called the fraction measure (FM) method, the fraction of each tissue material in each voxel v is estimated by taking into account the intensities of the voxels neighboring v. The second method, called uncertainty principle (UP) method, is based on the following postulate (Saha and Udupa, 2001): In any acquired image, voxels with the highest uncertainty occur in the vicinity of object boundaries. The removal of skin is achieved by means of mathematical morphology. Volume renditions have been created before and after applying the methods for several patient CT datasets. A mathematical phantom experiment involving different levels of PVE has been conducted by adding different degrees of noise and blurring. A quantitative evaluation is done utilizing the mathematical phantom and clinical CT data wherein an operator carefully masked out voxels with PVE in the segmented images. All results have demonstrated the enhanced quality of display of bone and soft tissue after applying the proposed methods. The quantitative evaluations indicate that more than 98% of the voxels with PVE are removed by the two methods and the second method performs slightly better than the first. Further, skin peeling vividly reveals fine details in the soft tissue structures.

Algorithms↗
PubMed2005

Soft-tissue tumors--role of diagnostic imaging.

The radiologic evaluation of soft-tissue masses has changed dramatically within the last two decades. Before the introduction of computer-assisted imaging, assessment of clinically suspicious soft-tissue masses was usually limited to radiographs. Although radiographs were sensitive to the identification of adipose tissue and soft-tissue mineralization, they provided little other diagnostic information. The emergence of CT improved this situation dramatically. Masses could be not only delineated with a great confidence but well staged with excellent depiction of anatomic detail. However, diagnosis remained problematic, with images sufficiently suggesting the correct histology in only a minority of cases: typically, lipomas and hemangiomas. The introduction of MR imaging markedly improved soft-tissue contrast and multiplanar image acquisition capabilities. Depiction of anatomic detail is of high importance in the evaluation of soft-tissue tumors. Attempts were made to develop rules analogous to those for bone tumors, for differentiating benign and malignant processes on the basis of lesion morphology and signal intensity.

Diagnostic Imaging↗
PubMed1996

Elastofibroma dorsi: a chest wall pseudotumor. Computed tomography and magnetic resonance imaging diagnosis.

"Elastofibroma dorsi" is a benign soft tissue mass usually arising between the chest wall and the inferior and medial aspects of the scapula. This lesion is not a true neoplasm but rather a reactive hyperplasia of elastic fibers. We present a case report of a woman with a subscapular mass, which was studied by computed tomography and magnetic resonance imaging. These are the methods of choice to study a soft tissue mass in order to define the inner structures and limits Computed tomography is helpful to guide a percutaneous biopsy, avoiding lesions to adjacent structures. Biopsy is recommended even when the imaging presentation seems typical of elastofibroma. The pathologic findings are diagnostic. No treatment is necessary in the asymptomatic patient. The treatment of choice for a symptomatic elastofibroma is local excison. There have been no reported cases of malignant transformation.

Female↗
PubMedDate not supplied

Axial computed tomographic anatomy of the foot: Part III. Forefoot.

Cross-sectional osseous and soft tissue anatomy of the human forefoot as demonstrated by high resolution computed tomography (CT) is described. This report serves an important baseline function because CT may be useful for the evaluation of a variety of forefoot disorders in the clinical setting.

Arteries↗
PubMed2006

Characterization of coronary atherosclerotic plaques by multidetector computed tomography.

Multidetector computed tomography (MDCT) provides 3-dimensional noninvasive visualization of the coronary arterial tree. We compared MDCT with intravascular ultrasound (IVUS) for assessment of severity of coronary artery stenosis and composition of atherosclerotic plaques in 40 patients (32 men; mean age 52 years, range 33 to 86) with documented coronary artery disease. Cross-sectional images obtained at 10-mm increments were assessed for percent decrease in luminal area. Atherosclerotic plaques were classified by IVUS as soft, fibrous, or calcified. On the matched multidetector computed tomograms, regions of interest of 1 to 3 mm in diameter were placed inside each plaque, and tissue contrast was measured in Hounsfield units. Obstructive coronary artery disease was found in 50 segments by IVUS and 57 segments by MDCT. Sensitivity for detecting obstruction >50% was 86.0% (95% confidence interval 72.6 to 93.7) and specificity was 90.2% (95% confidence interval 83.9 to 94.4). In total, 276 plaques were examined by IVUS and MDCT. There were 188 soft plaques (68.2%), 45 fibrous plaques (16.2%), and 43 calcified plaques (15.5%). Multidetector computed tomographic tissue contrast of soft, fibrous, and calcified plaques were 71.5 +/- 32.1, 116.3 +/- 35.7, and 383.3 +/- 186.1, respectively (p <0.001). Using a cut-off value of 185 HU, 273 of 276 plaques (99%) were correctly classified as calcified or noncalcified plaques. Using a cut-off value of 88 HU, 192 of 233 noncalcified plaques (82%) were correctly classified as fibrous or soft plaques. In conclusion, our data indicate that MDCT can provide important information concerning the composition of atherosclerotic plaques in addition to detecting luminal obstruction.

Adult↗
PubMed2005

Selective cyclooxygenase-2 inhibition reverses microcirculatory and inflammatory sequelae of closed soft-tissue trauma in an animal model.

BACKGROUND: Despite the common use of nonsteroidal anti-inflammatory drugs in the treatment of closed soft-tissue injuries, our understanding of the effect of these medications on tissue healing is incomplete. Using high-resolution multifluorescence microscopy, we investigated the efficiency of preinjury and postinjury treatment with the selective cyclooxygenase (COX)-2 inhibitor parecoxib to improve compromised perfusion of traumatized muscle tissue and to minimize secondary tissue damage. METHODS: With use of a pneumatically driven and computer-controlled impact device, closed soft-tissue trauma of the left hindlimb was induced in anesthetized rats that had had intravenous administration of 10 mg/kg of either parecoxib sodium (seven rats) or an equal volume of saline solution (seven rats). Seven additional animals received parecoxib two hours after the trauma, and seven animals without trauma served as controls. RESULTS: Time-course studies with use of both Western blot protein analysis and immunohistochemistry demonstrated a transient upregulation of COX-2 protein expression with peak levels eight to twelve hours after trauma and a return to near baseline level at eighteen hours. Regardless of whether parecoxib was administered before or after the injury, it completely restored microcirculatory impairment within the injured muscle. This was indicated by the mean values (and standard error of the mean) for nutritive perfusion (434 +/- 15 cm/cm(2) in animals treated before the injury and 399 +/- 8 cm/cm(2) in those treated after injury), nicotinamide adenine dinucleotide (NADH) levels (73 +/- 2 aU and 74 +/- 1 aU, respectively), and inflammatory cell interaction (184 +/- 36 and 186 +/- 32 n/mm(2), respectively, for leukocytes, and 1.0 +/-0.1 and 0.8 +/- 0.1 n/mm(2), respectively, for platelets) at eighteen hours after trauma, which were not different from those found in noninjured muscle tissue of controls. In contrast, skeletal muscle in saline solution-treated animals revealed persistent perfusion failure (296 +/-30 cm/cm(2)) with tissue hypoxia (NADH, 100 +/- 4 aU), and enhanced endothelial interaction of both leukocytes (854 +/- 73 mm(-2)) and platelets (2.3 +/- 0.5 n/mm(2)) at eighteen hours after trauma. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment of skeletal muscle soft-tissue trauma with parecoxib before as well as after injury is highly effective in restoring disturbed microcirculation. Moreover, a reduced inflammatory cell response helps to prevent leukocyte or platelet-dependent secondary tissue injury. These results deserve further investigation to prove that selective COX-2 inhibitors improve performance and promote healing following closed soft-tissue injury.

Animals↗
PubMed1987

Comparison of three methods of profile change prediction in the adult orthodontic patient.

Potential changes in the contour of the facial profile that accompany tooth movement can be important considerations in developing an orthodontic treatment plan. The objective of this study was to compare the accuracy of three different methods of predicting horizontal soft-tissue changes. Eighty-three nongrowing, orthodontically treated patients comprised the sample. Pretreatment and posttreatment lateral cephalometric hard- and soft-tissue landmark points were digitized. A coordinate system was defined, landmark coordinates were corrected for magnification, and then hard- and soft-tissue, angular, and linear measures were calculated by computer programs developed on a DEC PDP 11/44. The accuracy of prediction of soft-tissue landmark changes was compared for three prediction methods: (1) use of ratios of means of soft-tissue changes to corresponding hard-tissue changes, (2) use of a bivariate regression equation on corresponding hard-tissue landmark changes, and (3) use of stepwise multiple regression with hard-tissue changes and initial hard- and soft-tissue facial characteristics as predictor variables. For predicting changes of four soft-tissue points, multiple regression equations were slightly more accurate than ratio of means predictions. The standard errors of the estimate ranged from 0.7 to 1.1 mm for the multiple regression predictions; these were from 0.2 to 1.4 mm lower than those obtained for ratio of means predictions. The accuracy of the bivariate regression prediction technique fell between that of the other two methods. Examination of the residuals showed that the multiple regression equations consistently underpredicted the most extreme soft-tissue facial changes.

Adolescent↗
PubMed2005

Advantages of color B-mode imaging with contrast optimization in sonography of low-contrast musculoskeletal lesions and structures in the foot and ankle.

OBJECTIVE: The purpose of this study was to evaluate the utility of color B-mode imaging with contrast optimization in evaluating low-contrast lesions of the foot and ankle (Morton neuromas and plantar fasciitis). METHODS: The sonographic examinations of 49 consecutive patients with a diagnosis of plantar fasciitis or Morton neuroma imaged with both conventional gray scale imaging and color B-mode imaging with contrast optimization (Photopic; Siemens Medical Solutions, Mountain View, CA) were reviewed. In every patient, matched pairs of images obtained with conventional gray and color maps (Photopic) were acquired and stored as DICOM (Digital Imaging and Communications in Medicine) images on a sonographic workstation. Each image was assessed independently by 2 musculoskeletal radiologists trained in musculoskeletal sonography for overall image contrast (lesion to background), conspicuity of regional tissue boundaries, visualization of deep tissue boundaries, and how well the internal characteristics of the structure were visualized. RESULTS: Three-way analysis of variance showed that Photopic imaging resulted in statistically significantly improved overall image contrast, definition of regional soft tissue boundaries, including deep soft tissue boundaries, and depiction of the internal characteristics of the structure being examined. CONCLUSIONS: Color imaging with contrast optimization improves overall image contrast and better defines deep soft tissue boundaries and the internal morphologic characteristics of Morton neuromas and the plantar fascia compared with conventional gray scale imaging.

Analysis of Variance↗
PubMed2006

[Characteristics of computed tomography of allergic fungal sinusitis].

OBJECTIVE: To sum up the characteristics of computed tomography of allergic fungal sinusitis (AFS) and to compare the CT changes with the findings in the operation. The diagnostic role of CT scan was discussed. METHODS: The CT scans of 21 patients diagnosed as AFS were analyzed. The patients ranged from 15 to 50 years old,there were 17 males and 4 females. The CT was scanned with both bony and soft tissue windows. The preoperative examinations included nasal endoscopy, skin prick test, total serum IgE and nasal secretion smear. The findings in the operation were compared with the preoperative CT scans. Histopathology and fungal smear were done postoperatively. RESULTS: Endoscopy showed that all patients had polyps with wasfy yellow or inspissated white secretion. Nine cases (11 sides) showed yellow-to-brown material similar to peanut butter in the nasal cavities. Nasal CT scan demonstrated unilateral lesion in 10 cases (10 sides) and bilateral lesions in 11 cases (22 sides), who were all pansinus diseases. CT scan demonstrated a sheet areas of high-attenuation like "ground glass" within sinuses coupled with soft tissue image around them. Bone erosion of anterior skull base was encountered in 3 cases (4 sides). One case showed the intracranial extension. Twenty cases had conceived nasal endoscopic sinus surgeries. One case underwent endoscopic sinus surgery combined with coronal approach. The yellow-to-brown material (allergic mucin) was detected in the cavities of 17 cases. Four cases had green-to-brown secretion like mud. After follow-up of 6 months to 7 years, 14 cases were cured, 7 cases improved. Among them, 3 cases had to get revision surgeries because of recurrence 2 years after surgery. CONCLUSIONS: The characteristic of a sheet area of high-attenuation like " ground glass" within sinuses coupled with soft tissue image around them in computed tomography of nasal sinus, accompanied with invasive expansion or bone erosion, has a diagnostic significance for AFS.

Adolescent↗
PubMed1995

The role of MR imaging in the diagnosis of alveolar soft part sarcoma: a report of 10 cases.

OBJECTIVE: The objective of this study was to analyze the characteristics of alveolar soft part sarcoma using magnetic resonance imaging (MRI). DESIGN: MRI studies of pathologically proven alveolar soft part sarcomas (ASPS) in ten patients were reviewed and compared with computed tomographic (CT) studies and angiograms. PATIENTS: Ten patients presented with a soft tissue mass of the extremities, neck, axilla, or buttocks. MR images were obtained in all patients prior to surgical intervention, chemotherapy, or irradiation. RESULTS AND CONCLUSION: Although most soft tissue sarcomas are isointense relative to muscle or MRI T1-weighted images (T1WI), nine of the ten alveolar ASPS in the present study demonstrated high signal intensity on both T2 and T1WI. Flow voids were observed both at the core and at the margins of the tumors studied. Recognition of these characteristic MRI findings may lead to the early diagnosis of ASPS, especially when the clinical presentation is that of a slow-growing soft tissue mass in a young adult patient.

Adult↗
PubMedDate not supplied

Histiocytosis X of the temporal bone: CT findings.

The preoperative diagnosis of temporal bone histiocytosis X has been based traditionally on clinical examination, plain radiography, and pluridirectional tomography. Clinical misdiagnosis is common because otologic findings can mimic those of acute and chronic infectious ear disease. Similarly, plain radiographic and tomographic findings may be confused with those of mastoiditis, cholesteatoma, and temporal bone metastasis. The three cases of histiocytosis X presented here illustrate the advantages of CT compared with traditional radiographic methods in the diagnosis and staging of this disease. Computed tomography clearly delineates osseous involvement, including erosion of the bony labyrinth. Computed tomography also better defines the soft tissue margins of the granulomatous mass in relationship to the central nervous system and extratemporal tissues.

Adult↗
PubMed1987

[Reproducibility of anatomo-pathological diagnoses: use of the kappa-test in histo-prognostic grading of soft tissue sarcomas in adults].

In pathology, reproducibility of lesional diagnostic and classification is not perfect, particularly when dealing with rare tumors like soft-tissue sarcomas, the classification of which is complex. Reproducibility among many independent observers can be well appreciated by kappa statistics, which take into account the agreement rate expected by chance only. A study of the reproducibility of histological classification and grading of 25 soft-tissue sarcomas by 15 pathologists showed that the agreement was better for the grading. A review of some other applications of kappa statistics in pathology reported in the literature is presented.

Adult↗
PubMed2004

A rheological network model for the continuum anisotropic and viscoelastic behavior of soft tissue.

The mechanical behavior of soft tissue demonstrates a number of complex features including nonlinearity, anisotropy, viscoelasticity, and growth. Characteristic features of the time-dependent and anisotropic behavior are related to the properties of various components of the tissue such as fibrous collagen and elastin networks, large proteins and sugars attached to these networks, and interstitial fluid. Attempts to model the elastic behavior of these tissues based on assumptions about the behavior of the underlying constituents have been reasonably successful, but the essential addition of viscoelasticity to these models has been met with varying success. Here, a new rheological network model is proposed using, as its basis, an orthotropic hyperelastic constitutive model for fibrous tissue and a viscoelastic reptation model for soft materials. The resulting model has been incorporated into numerical and computational models, and is shown to capture the mechanical behavior of soft tissue in various modes of deformation including uniaxial and biaxial tension and simple shear.

Animals↗
PubMed2002

Soft tissue sarcoma mimicking chronic hematoma: value of magnetic resonance imaging in differential diagnosis.

We report six patients with soft tissue sarcoma mimicking traumatic hematoma. The lesions in these patients, showed huge hematomas and were characterized by rapid growth. Cytology of percutaneous; aspiration biopsy samples was performed in all six patients; however, in five patients, findings for malignant cells were negative. Consequently, they were misdiagnosed, resulting in a poor prognosis. We conducted a retrospective study in which we evaluated the clinical findings, the magnetic resonance (MR) images, and computed tomography (CT) scans of the soft tissue sarcomas forming huge hematomas in the lesion. MR imaging revealed the fine tumor mass with enhancement and characterized the hematoma in the lesion in a more precise fashion than did CT. We conclude that MR imaging is a suitable method for differentiating these soft tissue sarcomas from chronic traumatic hematoma.

Adolescent↗
PubMed1989

Application of video surgery to orthodontic diagnosis.

The purpose of this project was to develop a practical methodology for predicting the visual facial changes resulting from the movement of anterior teeth. The armamentarium includes an 8-bit audiovisual computer, a video camera, a digitizer, and a cephalogram of the patient. The system outputs the patient's profile on a personal computer video display. The image is superimposed on the soft tissue line of a digitized cephalogram plot on the same display. The video profile image is transformed from analog to digital signals. The profile image digitized by the computer is modified according to average ratios of soft tissue to hard tissue changes induced by modifications to the hard tissues. The program incorporates the spline function to smooth the profile image.

Audiovisual Aids↗
PubMedDate not supplied

Evaluation of canine lumbosacral stenosis using intravenous contrast-enhanced computed tomography.

The objective of this study was to evaluate intravenous contrast-enhanced computed tomography as a technique for predicting the within-level location(s) of compressive soft tissues in the canine lumbosacral spine. Pre-operative intravenous contrast-enhanced computed tomography of the L5-S3 vertebral levels was performed in 12 consecutive large breed dogs with lumbosacral stenosis. The images were evaluated for enhancement of soft tissues by two radiologists who were unaware of the surgical findings. For each within-level location (dorsal canal, ventral canal, right lateral recess, left lateral recess) enhancement was classified as present, absent or equivocal. The results were compared with the results of surgical exploration and histopathology of excised tissues. The positive predictive values of intravenous contrast-enhanced computed tomography for compressive soft tissues involving the dorsal canal, ventral canal and lateral recesses were 83%, 100%, and 81% respectively. Negative predictive values for compressive soft tissues involving these locations were 29%, 50%, and 40% respectively.

Animals↗
PubMedDate not supplied

Synovial sarcoma of the soft tissues: prognostic significance of imaging features.

OBJECTIVE: This study assessed the prognostic value of computed tomography (CT) and magnetic resonance (MR) imaging features in synovial sarcoma of the soft tissues. METHODS: CT and MR imaging studies were performed in 30 patients with pathologically confirmed synovial sarcoma of the soft tissues. CT and MR imaging findings obtained by 2 radiologists with agreement by consensus were compared for histopathologic features including tumor grade. Univariate analyses were conducted to clarify the impact of imaging findings on overall survival with a medium duration of 32 months. Multivariate analysis was estimated using a Cox proportional hazards model with the relative risk of each variable. RESULTS: Statistically significant imaging findings favoring a diagnosis of high-grade tumor included proximal distribution (P < 0.01), large tumor size (>10 cm, P < 0.05), the absence of calcification (P < 0.05), tumor possessing cyst (P < 0.01), the presence of hemorrhage (P < 0.05), and the presence of triple signal pattern (P < 0.05). Univariate analysis showed that proximal distribution (P < 0.05), tumor size larger than 5 cm (P < 0.01), the absence of calcification (P < 0.01), the presence of hemorrhage (P < 0.05), and the presence of triple signal pattern (P < 0.05) had a significant association with the disease-free survival (DFS). Multiple logistic regression models revealed that tumor size larger than 10 cm had a significant impact on the DFS with relative risk of 18.8 (P < 0.05). CONCLUSION: CT and MR imaging studies allow prognosis prediction in patients with synovial sarcoma of the soft tissues.

Adolescent↗