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Two patients with buttock abscesses developing as an extension of Crohn's disease are described. In each, the abscess extended through the sciatic foramen into gluteal soft tissues. Cross-sectional imaging, particularly computed tomography, is of major help in identifying these lesions and the pathway of spread.
A study was made of change of the spectrum (spectral transformation) of x-ray radiation while passing through the soft tissue. Thirty-two depth spectra computed by the Monte-Carlo method and 16 experimentally measured spectra including 9 depth spectra taken from literature, were analysed. A method of the calculation of an absorbed dose in the red bone marrow with account of spectral transformation was described. It was shown that neglect of this factor caused regular underestimation of the assessment of medullary doses, patients were exposed to, during x-ray procedures. The error can reach 40% for doses at local points of the red bone marrow and 1-7% for mean medullary doses with regard to the type of x-ray procedure and regimen of its performance.
Oculomotor disturbance resulting from orbital floor fractures have different etiologic factors, sometimes damage of one of the ocular motor nerves, caused by direct injury to the orbit; this damage occurs also to one or more of the extrinsic ocular muscles, especially the obliques; frequently, the diplopia is caused by prolapsed orbital tissues with or without muscle entrapment or by a muscle fibrosis; when the diplopia appears after orbital floor reconstruction there is often a palsy of the inferior rectus muscle in front of silicone implant or bone graft on the orbital floor. In oculomotor disturbance after orbital floor fracture, the first stage will be to recognize the mechanism of the diplopia by a clinical examination, motility in the nine positions, Hess Charts, binocular vision and field, forced duction, radiography and sometimes coronal computed tomography which also allow visualization of soft tissues densities, including all extraocular muscles. If there is an indication of orbital surgery, it will be done always in first; oculomotor surgery will be done if necessary at the second stage, if there is a permanent diplopia without evolution during six months. The purpose of the treatment is to obtain orthophoria in primary position and in down gaze. A series of cases of fracture of the orbital floor with resulting diplopia are described. The method, the time, and the indications of orbital or oculomotor surgery are discussed according the variety of cases.
Four case reports are presented which illustrate various patterns of calcific deposits in the heart. Valvular, myocardial, intracavitary, and coronary calcific deposits are illustrated, with emphasis on pathology and clinicopathologic-radiologic correlation. "Dystrophic" and "metastatic" calcifications are terms used to describe calcific deposits in abnormal and normal soft tissues, respectively. These terms are somewhat confusing in relation to the myocardium, however, as the chronologic sequence of cardiac injury is often uncertain. We suggest that these terms be avoided in relation to the heart, in favor of simple descriptive terms such as "myocardial calcific deposits." Many conditions, such as renal failure and hypercalcemia may contribute to the likelihood of soft tissue calcification, although a definite common etiology has not been identified. Likewise, soft tissue calcification has been difficult to diagnose premortem. The advent of ultrafast (cine) computed tomography may provide a quick, noninvasive, highly sensitive and specific method for diagnosis of soft tissue calcific deposits in the future.
We reviewed 14 patients with primary bone tumors of the proximal tibia whose plain radiographs suggested possible posterior soft tissue extension. Four tumors extended posteriorly and displaced the major vessels on angiography. However, high resolution computed tomography (CT) showed the normal popliteus muscle lying between the tibia and the major vessels in three instances. When CT was equivocal, angiography in the lateral projection with the knee flexed was helpful for further evaluation.
In this work, we aim at validating some soft tissue deformation models using high resolution Micro Computed Tomography (Micro-CT) and medium resolution Cone-Beam CT (CBCT) images. These imaging techniques play a key role in detecting the tissue deformation details in the contact region between the tissue and the surgical tool (probe) even for small force loads, and provide good capabilities for creating accurate 3D models of tissues. Surgical simulations rely on accurate representation of the mechanical response of soft tissues subjected to surgical manipulations. Several finite element (F.E.) models have been suggested to characterize soft tissues. However, validating these models for specific tissues still remains a challenge. For our validation, ex vivo lamb liver is chosen to validate the linear elastic model (LEM), the linear viscoelastic model (LVEM), and the neo-Hooke hyperelastic model (NHM). We found that the LEM is more applicable to lamb liver than the LVEM for small force loads (< 40 g) and that the NHM is closer to reality than the LVEM for this same range of force loads.
The authors discuss various radiographic imaging techniques for pedal soft tissue lesions. These include xeroradiography, angiography, ultrasound, computed tomography, and magnetic resonance imaging. Illustrative cases of each modality, as well as an evaluation of advantages and disadvantages, are presented.
OBJECTIVES: The formation of the dental primordial should be visualized with special reference to characteristic differences for each single primordium. Until today, it has not been clear how traffic of the ameloblasts is controlled, how the folding pattern of the occlusal relief is generated or how the enamel production is terminated at the enamel surface. DESIGN: Using computer-aided reconstructions from histological serial sections, the dental primordial were visualized and, using fractured enamel specimens, the traces of each single ameloblast were followed by means of scanning electron microscopy. In this way, the developmental movements of the inner enamel epithelium can be reconstructed. RESULTS: Gathering morphological knowledge, three-dimensional polygon sets of shape data were input into a computer workstation and animated by means of the software Soft Image (Microsoft). CONCLUSIONS: The development of the human primary and permanent dentition was animated to simulate growth.
Radiology plays an important role in the diagnosis of temporomandibular disorders. Different techniques are used with computed tomography offering simultaneous imaging of bone and soft tissues. It is therefore suited for visualization of the articular disk and may be used in patients with suspected internal derangements and other disorders of the temporomandibular joint. Previous research suggests advantages to direct sagittal scanning, which requires special positioning of the patient and a sophisticated scanning technique. This study describes the development of a new technique of direct sagittal computed tomographic imaging of the temporomandibular joint using a specially designed patient table and internal light visor positioning. No structures other than the patient's head are involved in the imaging process, and misleading artifacts from the arm or the shoulder are eliminated. The use of the scanogram allows precise correction of the condylar axis and selection of exact slice level.
We evaluated 22 soft-tissue masses in the extremities using magnetic resonance (MR) imaging. The twenty-two cases consist of 14 benign lesions and 8 malignant lesions. MR imaging is available to provide the representation of the extent of the masses, though characteristic diagnosis of them could not be identified. We think that there are more advantages to using MR imaging rather than computed tomography (CT) in the evaluation of soft-tissue masses in extremities.
RATIONALE AND OBJECTIVES: Reader performance and image quality wee assessed for standard film, computed film, and computer monitor radiography viewing formats in the evaluation of skeletal extremity trauma. MATERIALS AND METHODS: Three radiologists and three orthopedic surgeons interpreted 27 skeletal radiographs obtained with equivalent technical parameters. Readers evaluated standard film, computed film, and computer monitor formats randomly for fracture and soft-tissue abnormalities. Sessions were videotaped, and eye motion was recorded. RESULTS: No statistically significant differences were found between image formats for true-positive or false-positive findings of trauma indicators. Findings were classified as false-negative based on eye position fixation times. Search errors (lesion not fixated) accounted for 21.7%, 20.6% and 17.1% of false-negative errors with the computer monitor, computed film, and standard film formats, respectively. Combined recognition errors and decision errors were 78.3%, 79.4%, and 82.9%, respectively. Viewing times were longest for the computer monitor images (P < .001). Image quality, contrast, and sharpness were rated highest for computed radiographs (P = .001). Radiologists had a higher true-positive decision rate than orthopedic surgeons (P = .03). CONCLUSION: No statistically significant differences were seen in reader performance among viewing formats. The computed film format received the highest quality rating, and workstation viewing times were longest.
BACKGROUND: The transcutaneous transorbital approach to medial orbital wall fractures facilitates placing a large implant or autogenous graft. However, its major disadvantage is the difficulty of accurately reducing the fractured medial orbital wall and herniated soft tissues with minimal morbidity. METHODS: To resolve this problem, a combined transcutaneous transethmoidal/transorbital approach through the same skin incision was developed at the Chonnam National University Medical School. Between 1997 and 2003, this approach was used in 54 patients with pure medial orbital blowout fractures. All fractures were larger than 2 cm in defect size and had 3 mm or more of bone displacement. RESULTS: Postoperative computed tomographic scans showed complete release of entrapped soft tissues and accurate reconstruction of bone defects in all cases. Complications related to the operation such as intraorbital and intramuscular hemorrhage, infection, and eyeball and optic nerve injuries were not observed, except in two cases with slight implant displacement. Follow-up ranged from 2 to 22 months, with an average of 9 months. Forty-one patients were evaluated 6 months or more after their reconstructive procedure. At the time of surgery, diplopia was present in 39 patients, eyeball movement limitation in 35 orbits, and enophthalmos of more than 2 mm in 16 orbits. Postoperatively, diplopia and eyeball movement limitation were resolved in most cases. Two patients had persistent diplopia for more than 1 year after surgery, and one of these needed extraocular muscle surgery. Enophthalmos of more than 2 mm developed in three orbits, but enophthalmos of more than 3 mm was not observed in any orbit. Cosmetic results at the incision site were acceptable in all patients. CONCLUSIONS: The combined transcutaneous transethmoidal/transorbital approach is a safe procedure that can be performed with minimal morbidity; it offers the advantages of both the transcutaneous approach and the trans-nasal approach. Therefore, the authors suggest that this method be considered as a surgical alternative for the treatment of medial orbital blowout fractures, especially large and combined fractures of the medial wall and other parts of the orbit.
OBJECTIVE: The analysis of lateral videofluoroscopic images of velar movements during speech is a commonly used tool in the management of the cleft palate patient. This study tests the general hypothesis that measurements of velar movements taken from lateral videofluoroscopic images are accurate and reliable. METHOD: A measurement system was used that allowed for the rapid assessment of velopharyngeal distance, soft palate velocity during the closure cycle, extension of the soft palate at maximum closure, and the angular lift of the soft palate above the plane of the hard palate. Ten recordings of soft palate movement during speech were randomly chosen from lateral X-rays of 27 normal adults. The video recordings were captured by digital frame grabber for subsequent analysis by three operators using a standard PC that was running image-analysis software. The uncertainties associated with the above measurements were analyzed in terms of the errors introduced by the inherent calibration and nonlinearity of the imaging system, the inaccuracy of the patient setup, and the operator-dependent measurement error. RESULTS: For both absolute dimensions and ratiometric measurements, the measurement uncertainties related to the inherent nonlinearity in the imaging system were shown to be less than 2%. Typical patient misalignments as a result of a 10 degree head rotation and a 10-mm translation out of the measurement plane introduced errors of between 2% and 3%. Results showed that the average standard deviation for measurement of gap size was 1.2 mm, extension ratio was 0.11, angular lift was 3.1 degrees, and soft palate velocity was 15.5 mm/second. The intra-class correlation coefficient generally showed a good agreement between operators, typically in the range 0.8 to 0.9. CONCLUSION: Measurements of velopharyngeal distance, extension of the soft palate at maximum closure, and the angular lift of the soft palate above the plane of the hard palate assessed from lateral videofluoroscopic images are reliable and accurate. The soft palate velocity during the closure cycle can also be determined, but clinical interpretations based on this parameter should be constrained by the measurement uncertainties.
The average in vivo chest computed tomographic (CT) attenuation number (air = -1,000, soft tissue = 0, perflubron = +2,300 Hounsfield units [HU]) of 10 ventrodorsal-oriented lung segments was calculated to assess the distribution of gas and perflubron in 14 oleic acid lung-injured adult sheep during partial liquid ventilation (PLV, n = 7) or gas ventilation (GV, n = 7). Partial liquid ventilation was associated with a significant decrease in shunt fraction (PLV = 40 +/- 12%, GV = 76 +/- 12%, p = 0.004). Computed tomographic attenuation data during expiration (HUexp) demonstrated minimal gas aeration in GV animals in the dependent (segments 6-10) lung zones (HUexp = -562 +/- 108 for segments 1-5, HUexp = -165 +/- 104 for segments 6-10, p = 0.015). During PLV, perflubron was predominantly distributed to the dependent lung regions (HUexp = 579 +/- 338 for segments 1-5, HUexp = 790 +/- 149 for segments 6-10, p = 0.04). The ratio of the inspiratory to expiratory HU (HUinsp/exp) was greater in dependent than nondependent regions (mean HUinsp/exp segments 1-5 = 0.56, segments 6-10 = 0.81, p = 0.01), indicating that during inspiration relatively more gas than perflubron was distributed to the nondependent lung regions. We conclude that during PLV in this lung injury model, (1) gas exchange is improved when compared with gas ventilation, (2) perflubron is distributed predominantly to the dependent regions of the lung, and (3) although gas is distributed throughout the lung with each inspiration, more gas than perflubron goes to the nondependent lung regions.
Ninety patients with musculoskeletal soft-tissue tumors and tumorlike masses examined with conventional radiography, ultrasonography, computed tomography, and other imaging modalities were reviewed. Computed tomography plays a key role in the preoperative assessment of primary malignant skeletal tumors, particularly in the detection of intramedullary and extraosseous tumor component. Ultrasonography is particularly helpful in defining benign soft-tissue masses and primary malignant soft-tissue tumors. Radionuclide bone scan is of value in evaluating the extent of osseous involvement or in detecting unsuspected skeletal metastases or skip lesions in patients with an apparent solitary skeletal tumor.
OBJECTIVES: This study was designed to determine the precision and accuracy of anthropometric measurements using three-dimensional computed tomography (3D-CT) volume rendering by computer systems for craniofacial clinical applications, and to compare the craniometric landmarks using bone and soft tissue protocols. METHODS: The study population consisted of 13 cadaver heads that were examined with spiral CT. The archived CT data were transferred to a workstation, and 3D-CT volume rendered images were generated using computer graphics tools. Linear measurements (n = 10), based upon conventional craniometric anatomical landmarks (n = 08), were identified in 2D-CT and in 3D-CT images by two radiologists twice each independently, and then performed by 3D-CT imaging using a computer graphics systems using bone and soft tissue protocols. In total, 520 imaging measurements were made. The soft tissues were subsequently removed from the cadaver heads and the measurements were repeated using an electromagnetic 3 Space trade mark digitizer. RESULTS: The results demonstrated no statistically significant difference between interobserver and intraobserver measurements or between imaging and physical measurements in both 3D-CT protocols. The standard error was found to be between 0.45% and 1.44% for all the measurements in both protocols, indicating a high level of precision. Furthermore, there was no statistically significant difference between imaging and physical measurements (P > 0.01). The error between the mean actual and mean 3D-based linear measurements was 0.83% for bone and 1.78% for soft tissue measurements, demonstrating high accuracy of both 3D-CT protocols. CONCLUSIONS: 3D-CT volume rendering images using craniometric measurements can be used for anthropological studies involving craniofacial applications.
Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an engineering approach with the developmental biology concept of embryonic tissue fluidity enables the creation of a new rapid prototyping 3D organ printing technology, which will dramatically accelerate and optimize tissue and organ assembly.
The differentiation of palatal from non-palatal snoring is very important for ENT surgeons trying to determine whether palatal surgery would be curative. At present sleep nasendoscopy is the accepted method. Palatal vibration produces marked modulation of sound loudness at low frequency (below approximately 100 Hz). We calculate a crest factor for the sound waveform (ratio of peak to root mean square (rms) value in any given epoch), as a measure of the degree of modulation. Free-field snore sounds were recorded from 11 supine adult patients under intravenous sedation (midazolam), using a digital tape recorder. Recordings were transferred to a PC (sampling frequency 11 kHz), and analysed using code written by us. Direct visual confirmation of the site of snoring was gained from simultaneous sleep nasendoscopy, taken as the gold standard. In six patients the dominant site was the soft palate. The non-palatal group (five patients) comprised one epiglottic, two hypopharyngeal and two tongue base snorers. The crest factor was found to be significantly higher for palatal snorers (p < 0.01, Student-t or Mann-Whitney tests). Furthermore, palatal could be distinguished from non-palatal snorers on the basis of crest factor alone in all 11 cases, making this a promising non-invasive diagnostic technique.