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PubMed2005

Computed tomography and cross-sectional anatomy of the thorax in clinically normal dogs.

OBJECTIVE: To provide a detailed anatomic description of the thorax in clinically normal dogs by means of computed tomography. ANIMALS: 4 clinically normal adult German Shepherd Dogs weighing 28 to 37 kg. PROCEDURE: Dogs were anesthetized and positioned in ventral recumbency for computed tomographic (CT) examination of the thorax. A CT image from the thoracic inlet to the diaphragm was made by use of a third-generation scanner with a slice thickness of 5 mm. Individual images were reviewed by use of soft tissue (window width, 250 Hounsfield units; window level, 35 Hounsfield units) and lung (window width, 1,000 Hounsfield units; window level, -690 Hounsfield units) settings. One dog, weighing 28 kg, was euthanatized, bound on a wooden frame in the same position as used for CT examination, and frozen at -14 degrees C until solid. By use of an electric band saw, the frozen thorax was sectioned at 10-mm-thick intervals. Slab sections were immediately cleaned, photographed, and compared with corresponding CT images. RESULTS: Anatomic sections were studied, and identified anatomic structures were matched with structures on corresponding CT images. Except for some blood vessels and details of the heart, most of the bony and soft tissue structures of the thorax discerned on anatomic slices could be found on matched CT images. CONCLUSIONS AND CLINICAL RELEVANCE: Because CT images provide detailed information on most structures of the canine thorax, results of our study could be used as a guide for evaluation of CT images of the thorax of dogs with thoracic diseases.

Animals↗
PubMed2005

Structural and material changes in the aging thorax and their role in crash protection for older occupants.

The human body undergoes a variety of changes as it ages through adulthood. These include both morphological (structural) changes (e.g., increased thoracic kyphosis) and material changes (e.g., osteoporosis). The purpose of this study is to evaluate structural changes that occur in the aging bony thorax and to assess the importance of these changes relative to the well-established material changes. The study involved two primary components. First, full-thorax computed tomography (CT) scans of 161 patients, age 18 to 89 years, were analyzed to quantify the angle of the ribs in the sagittal plane. A significant association between the angle of the ribs and age was identified, with the ribs becoming more perpendicular to the spine as age increased (0.08 degrees/year, p=0.012). Next, a finite element model of the thorax was used to evaluate the importance of this rib angle change relative to other factors associated with aging. A three-factor, two-level factorial design was used to assess the relative importance of rib cage morphology ("young" and "old" rib angle), thickness of the cortical shell (thick = "young" and thin = "old"), and the bone material properties ("young" and "old") on the force-deflection response and injury tolerance of the thorax. The simulations showed that the structural and material changes played approximately equal roles in modulating the force-deflection response of the thorax. Changing the rib angle to be more perpendicular to the spine increased the effective thoracic stiffness, while the "old" material properties and the thin cortical shell decreased the effective stiffness. The offsetting effects of these traits resulted in similar effective thoracic stiffness for the "elderly" and baseline thoracic models, which is consistent with cadaver data available in the literature. All three effects tended to decrease chest deflection tolerance for rib fractures, though the material changes dominated (a four- to six-fold increase in elements eliminated using a maximum strain criterion). The primary conclusion, therefore, is that an older person's thorax, relative to a younger, does not necessarily deform more in response to an applied force. The tolerable sternal deflection level is, however, much less.

Journal Article↗
PubMed2004

[Visual impression of photographic density of lung, thorax, and mediastinum in chest CT images: verification of optical illusion by visual subjective evaluation of medical images].

Even if the brain in head CT images is shown physically at the same photographic density, optical illusion (assimilation, contrast, etc.) occurs and practical density can be observed psychologically differently. Therefore, in this study, in order to clarify the visual characteristics of lightness perception in chest CT images, I attempted to compare it with the visual impression of the photographic density of lung, thorax, and mediastinum, using visual subjective evaluation. The results were as follows. (1) In the case of the preferential window setting of lung, both thorax and mediastinum, which surround the lung, are recognized as a wide white frame with contrast, and the photographic density of the lung psychologically seems blackish as a result of the "picture frame effect". (2) In the case of the preferential window setting of thorax and mediastinum, the visual impression of the photographic density varies among observers. (3) In the case of the virtual double window setting of lung, thorax, and mediastinum, under the influence of both high-density and low-density areas in the radiological anatomy of thorax and mediastinum, the photographic density of lung psychologically appears whitish as a result of the "grouping theories" of lightness computation. Further, under the influence of original gray lung, the photographic densities of thorax and mediastinum psychologically appear to be whitish.

Humans↗
PubMed1978

Finite element dynamic structural model of the human thorax for chest impact response and injury studies.

The component model modal synthesis technique has been successfully adapted to the finite element structural dynamic model of the human thorax for chest impact response and injury studies. The complete thorax was modeled as an assembly of a thorax module with viscera subsystems. The module was further subdivided into rib components. Major model development was conducted at the component level to provide cost saving and modeling flexibility. The results show that the thorax can be successfully treated as a linear system. A two-step procedure was developed to obtain viscera response. The analysis results of THORAX III, a first cut thorax model, were favorably compared with Kroell-Nahum cadaver experiments. The sensitivity of the chest response due to variation in input pulse shape and peak force were analyzed. The pulse shape can affect the force-deflection relationships while peak force affects the peak response. Further sensitivity studies and experiments are proposed.

Biomechanical Phenomena↗
PubMed2004

A high resolution computer model for sound propagation in the human thorax based on the Visible Human data set.

A parallel supercomputer model based on realistic tissue data is developed for sound propagation in the human thorax and the sound propagation behavior is analyzed under various conditions using artificial sound sources. The model uses the Visible Human male data set for a realistic representation of the human thorax. The results were analyzed in time and frequency domains. The analysis suggests that lower frequencies of around 100 Hz are more effectively transmitted through the thorax and that the spatial confinement of sound waves within the thorax results in a resonance effect at around 1500 Hz. The results confirm previous studies that show the size of the thorax plays a significant role in the type of sound generated at the chest wall.

Acoustics↗
PubMed2002

Pelvis-thorax coordination in the transverse plane during gait.

The coordination between horizontal pelvic and thoracic rotations during treadmill walking was studied in ten subjects. Previous studies have considered the relative phase using the mean to characterize coordination mode, and the S.D. as an index of its stability. However, to use S.D. of relative phase as a measure for coordinative stability, the underlying oscillations have to be phase-locked at a certain value. Random fluctuations around this value can then be viewed as stochastic perturbations of a stable fixed point, resulting in a unimodal distribution of relative phase. Using methods of circular statistics this study shows that these conditions were not met in pelvis-thorax coordination. Spectral analyses revealed that, as walking velocity increased, a triphasic component emerged in the pelvic rotations, while the thoracic rotations remained harmonic across all walking velocities. These findings refute the use of standard relative phase measures to capture pelvis-thorax coordination. An alternative measure is introduced, namely the difference between the continuous Fourier phases of the component oscillations as determined for the main frequency of the thorax oscillation. With this measure, pelvis-thorax coordination was found to evolve from in-phase coordination towards antiphase coordination as walking velocity increased. This method may be used to assess reliably the properties of pelvis-thorax coordination in both healthy and pathological gait patterns in the future.

Adult↗
PubMed1995

Chemical guidance of Onchocerca lienalis microfilariae to the thorax of Simulium vittatum.

The behavioural responses of Onchocerca lienalis microfilariae (mf) to tissue factors of the surrogate black fly host, Simulium vittatum, were studied using a novel in vitro bioassay. Mf accumulated towards thoracic tissues to a density 4 times higher than towards abdominal tissues, despite the larger surface area and volume of abdominal tissues. Mf migrated toward thoracic tissues regardless of whether or not contact with thoracic tissues was possible. Therefore, mf directed themselves toward the thorax rather than arresting their movement after they make contact with thoracic tissues. Chemical cue(s) provided a principal guidance for mf to locate thoracic tissues. Mf lost their ability to differentiate thoracic and abdominal tissues following addition of thoracic attractant(s) to excised abdomens and reversed their differential response when excised thoraces were depleted of chemical cue(s). Mf did not respond to salivary gland product, but to other thoracic factor(s). Intact thorax that was connected to 1-2 abdominal segments attracted considerably less mf than excised thorax. However, intact thorax attracted more mf than excised abdomen. Abdominal tissue size did not affect thorax attractiveness. Involvement of a large molecular weight protein(s) was suggested by the high attractiveness of the 100 kDa Centricon concentrator retentate and complete precipitation of attractant(s) by ethanol.

Animals↗
PubMed1994

Gene-environment interaction for body size and larval density in Drosophila melanogaster: an investigation of effects on development time, thorax length and adult sex ratio.

We measured the effect of larval density on thorax length, development time, sex ratio and a measure of total fitness, using strains of Drosophila melanogaster artificially selected for increased thorax length, control lines otherwise cultured in an identical way, and the base stock from which the lines had been derived. We used the addition experimental design (Mather & Caligari, 1981). No genotype-environment interaction was observed when comparing the reduction in thorax length of 'large' and 'control' lines with increasing larval density for any culture series, i.e. rank ordering of genotypes and additive genetic variances remained the same in all the environments tested. In contrast, the reduction in thorax length for the base stock as density increased was proportionally smaller than that of the 'large' and 'control' lines. Development time increased more rapidly with larval density in the 'large' lines than in the 'controls' or base stock. Sex ratio was unaffected by larval density but thorax length and the development time of females were more affected than those of males by increasing larval density. The estimate of total fitness showed clear evidence of gene-environment interaction for the effect of body size on fitness, with genetically large individuals at an increasing disadvantage with increasing larval density.

Animals↗
PubMed1975

Properties of a free and a solubilized form of bound alpha,alpha-trehalase purified from honey bee thorax.

The free and bound forms of alpha,alpha-trehalase (EC 3.2.1.28) of the honey bee thorax were separated and the bound enzyme was solubilized by raising the pH to 8.0 for 10 h. Both enzymes were purified. They were homogeneous as determined by several electrophoretic criteria. It was found that the two enzymes had very similar Km's (each about 0.89 mM), Vm's (53.2 and 54.3 U/mg for free and solubilized, respectively), inhibition characteristics, specificities (both only hydrolyzed alpha,alpha-trehalose), pH maxima (each had maxima at about 3.5 and 6.5), molecular weights (65,000), isoelectric points (5.1), reactivities to sulfhydryl reagents, electrophoretic mobilities, activation energies (about 12.8 kcal/mol), and similar stabilities to heat, pH, and urea. Some significant differences between the two enzymes were, however, found: the solubilized alpha,alpha-trehalase floated at 70% saturation of ammonium sulfate while the free alpha,alpha-trehalase did not; the solubilized alpha,alpha-trehalase did not dissociate into subunits as readily as did the free one; and the solubilized alpha,alpha-trehalase was found to bind more readily to a hydrophobic grouping than the free enzyme. In addition to these comparisons, three new findings relating to thorax alpha,alpha-trehalases are reported. (1) Thorax alpha,alpha-trehalases are strongly inhibited by beta-glucosides (Ki values of about 8 x 10(-4) M); (2) under certain conditions thorax alpha,alpha-trehalases from honey bees dissociated into subunits of one-half the normal molecular weight; (3) honey bee thorax alpha,alpha-trehalases have unusual biphasic pH activity profiles.

Animals↗
PubMed2005

Monte carlo dose calculations in conventional thorax fields for 60Co photons.

PURPOSE: Our purpose was to apply the MCNP4C Monte Carlo (MC) code for dose calculations in the thorax region and compare the results with those of measurements and a conventional treatment planning system (TPS). MATERIALS AND METHODS: We modeled a Theratron 780E 60Co unit and benchmarked our modeling with percent depth doses (PDDs), beam profiles, and output factors measured in a water phantom. For PDDs and beam profiles, the differences between measurements and MC calculations were less than 1% and 2%, respectively. We used an anatomic thorax phantom for evaluation of a conventional TPS and our MC calculation results. RESULTS: In comparing the results of calculations and measurements for our thorax geometries, the errors of conventional and MC methods were 20% and 2%, respectively. For the anterior mediastinal field and large thorax field the accuracy of the conventional method was acceptable, but for small fields of lateral thorax irradiation, the error of the conventional method was as high as to 20%. In all MC calculations, discrepancy from the measurements was less than 2%. CONCLUSION: Our results showed that the MCNP4C MC code could be used in dose calculations in treatment planning for 60Co photon irradiation. In addition, the application of the MC method for dose calculations in radiotherapy with 60Co photons was recommended.

Algorithms↗
PubMed2004

SYT-SSX fusion genes in synovial sarcoma of the thorax.

Synovial sarcoma (SS) is characterized by a chromosomal translocation resulting in the expression of an SYT-SSX chimeric transcript, usually SYT-SSX1 or SYT-SSX2. Synovial sarcoma typically originates in the limbs, and its location in the thorax is rare. Synovial sarcomas are usually classified into three histologic subtypes: biphasic, monophasic and poorly differentiated tumors. The detection of the characteristic chimeric transcript often contributes to a histopathological diagnosis, especially when the tumor arises in an unusual location. Previous studies have shown that SYT-SSX1 is the most common SYT-SSX fusion transcript in biphasic synovial sarcomas of the limbs. Here, we report two cases of synovial sarcoma originating in the thorax. The presence of SYT-SSX2 chimeric transcripts was confirmed by reverse transcript polymerase chain reaction (RT-PCR) and a direct sequencing analysis in both cases. The tumor in case 1 originated from the pericardium, which is an exceedingly rare site for primary synovial sarcoma; only three other cases of synovial sarcoma originating in the pericardium have been previously reported. Case 2 exhibited a biphasic synovial sarcoma of the mediastinum containing an SYT-SSX2 fusion transcript, which is a rare fusion type in biphasic synovial sarcomas of the limbs. We reviewed previous reports of thoracic synovial sarcomas containing an analysis of the SYT-SSX fusion transcript and found that case 2 in the present study was the first description of a biphasic synovial sarcoma of the thorax with an SYT-SSX2 fusion transcript. However, the number of reported cases was not sufficient to conclude that SYT-SSX2 fusion in biphasic synovial sarcoma of the thorax is, indeed, rare. Further genetic analysis is needed to fully understand the biological and clinical features of synovial sarcoma originating in the thorax.

Adolescent↗
PubMed2000

9. Assessment of Intrathoracic Metastatic Lung Cancer using FDG-PET and CT of the Thorax.

Purpose: The purpose of this study was to assess the accuracy in localizing mediastinal, hilar and intraparenchymal lymphadenopathy in patients with primary lung carcinomas, using FDG-PET and CT of the thorax and to correlate with surgical pathology.Method: Thirty-five patients with primary lung carcinomas and minimal metastatic lymph node involvement, (either N solidus in circle or N1 disease) underwent FDG-PET and CT of the thorax prior to surgical intervention. Both FDG-PET and CT of the thorax were blindly read independent of one another.Results: Histologically, 23 patients had negative lymph nodes (N solidus in circle) and 12 patients had N1 disease. The imaging performance characteristics for FDG-PET and CT of the thorax in N solidus in circle/N1 disease was evaluated and reported in Table 1.Conclusion: This study demonstrates the higher specificity, accuracy, PPV, and NPV of FDG-PET over CT of the thorax in patients with minimal lymph node disease.

Journal Article↗
PubMed1999

The role of thorax imaging in staging head and neck squamous cell carcinoma.

The overall survival rate for patients with head neck squamous cell carcinoma remains disappointingly static despite improved locoregional control. This has been attributed to the development of distant metastases and second primary malignancies in these patients, a large proportion of which occur in the thorax. We retrospectively analysed the incidence of thoracic malignancies in 138 patients presenting with newly diagnosed (n = 107) or recurrent (n = 31) cancer of the head and neck over a 4-year period. All 138 patients had undergone both computerised tomography of the thorax (CT) and conventional chest radiography within one month of presenting with biopsy proven squamous cell carcinoma. Seventeen percent of these were found to have simultaneous thoracic malignancies. CT thorax was more sensitive in detecting simultaneous thoracic malignancies compared with standard chest X-ray (24/138 versus 9/138, odds ratio of 3:1 in favour of CT). All thoracic malignancies detected by chest X-ray were also detected by CT thorax. Patients presenting with recurrent tumors were significantly more likely to have simultaneous thoracic malignancies than those with newly diagnosed cancer (11/31 versus 13/107, chi2 test with Yates correction, chi2 = 4.66, p = 0.03). The primary site (laryngeal, oral or pharyngeal) or presence of nodal disease did not have an effect on the incidence of simultaneous thoracic malignancies. The presence of distant metastases and second primary malignancies has major implications in the management and prognosis of patients presenting with head and neck squamous cell carcinoma, with a large proportion of such patients succumbing to their disease within one year of diagnosis. As CT scanning of the thorax was a more effective screening investigation than standard chest X-ray in the detection of simultaneous thoracic malignancy, we recommend it for use in the staging of patients presenting with cancer of the head and neck.

Adult↗
PubMed1989

Analytical studies of injury criteria for the thorax.

The viscous criterion is a recently developed criterion to assess injury severity of the human thorax. In the viscous criterion, the peak viscous response, which is defined as the maximum product of deformation velocity and compression of an object, is proposed as a predictor of injury risk. However, the physical meaning of the criterion is not very clear. In this paper, the mathematical properties of the viscous criterion are analyzed. A mechanical thorax model is then used to relate the criterion to the physical quantities of the model using energy concepts. It is found that the so-called peak viscous response is strongly related to the peak energy storing rate of the thorax which is not related to the viscosity of the thorax. It is also shown that the viscous response of the thorax is given by the integral of the velocity squared with respect to time. The analysis is further expanded to a more general case to result in four criteria based upon the energy concepts. A hypothesis for injury assessment is proposed by using the four criteria.

Biomechanical Phenomena↗
PubMed1999

Blowfly flight and optic flow. I. Thorax kinematics and flight dynamics

The motion of the thorax of the blowfly Calliphora vicina was measured during cruising flight inside a cage measuring 40 cmx40 cmx40 cm. Sensor coils mounted on the thorax picked up externally generated magnetic fields and yielded measurements of the position and orientation of the thorax with a resolution of 1 ms, 0.3 degrees and 1 mm. Flight velocities inside the cage were up to 1.2 m s-1, and accelerations were up to 1 g ( approximately 10 m s-2) vertically and 2 g horizontally. During flight, blowflies performed a series of short (approximately 20-30 ms) saccade-like turns at a rate of approximately 10 s-1. The saccades consisted of a succession of rotations around all axes, occurring in a fixed order. First, a roll was started. Second, the rolled thorax pitched (pulling the nose up) and yawed, resulting in a turn relative to the outside world. Finally, the thorax rolled back to a level position. Saccades had yaw amplitudes of up to 90 degrees, but 90 % were smaller than 50 degrees. Maximum angular velocities were 2000 degrees s-1, and maximum accelerations were 10(5 ) degrees s-2. The latter correspond to torques consistent with the maximal force (2x10(-3 )N) that can be generated by the flight motor as inferred from the maximal linear acceleration. Furthermore, the sequence of energy investment in consecutive rotations around different axes appears to be optimized during a saccade.

Journal Article↗
PubMed1996

[Treatment outcome of surgical thoracic wall stabilization of the unstable thorax with and without lung contusion].

Between 1988 and 1994, 295 patients with blunt chest trauma were treated. Forty-two patients had flail chest, requiring mechanical ventilation. Open reduction and osteosynthesis (ASIF reconstruction plates or isoelastic rip clamps) of the chest wall were performed in 20 patients. For the purpose of analysis we separated the patients into five groups: group I (n = 10) had chest wall stabilization in flail chest without pulmonary contusion (average ISS 31.0, AIS-thorax 4.1); group II (n = 10) had chest wall stabilization in flail chest with pulmonary contusion (average ISS 37.0, AIS-thorax 4.3); group III (n = 18) had fail chest without pulmonary contusion (average ISS 36.3, AIS-thorax 4.2); group IV (n = 4) had flail chest with pulmonary contusion (average ISS 37.8, AIS-thorax 4.0); group V (n = 29) had pulmonary contusion without flail chest (average ISS 34.5. AIS-thorax 4.1). With open reduction and internal fixation of unstable chest wall segments, the duration of ventilatory support, mortality and pneumonia were significantly reduced to 6.5 (1-25) days in group I (mortality rate 0%, incidence of pneumonia 10%) compared to group III (duration of ventilatory support 26.7 days, mortality rate 39%, incidence of pneumonia 16%). Eighty percent of the patients in group I were extubated within 5 days postoperatively. In group II 4 patients underwent emergency thoracotomy for intrathoracic injuries (3 of them died between 4 h and 31 days) and 2 patients for laceration of the lung. In all these cases the chest wall was stabilized after thoracotomy. One patient was stabilized for a deformation of the chest wall and two for paradoxical movement of the chest wall during weaning from the respirator. The mean duration of ventilation in group II was 30.8 (10-112) days (mortality rate 30%, incidence of pneumonia 30%). No complications related to the osteosynthesis arose during the follow-up. In conclusion, the best indication for early operative chest wall stabilization is flail chest without pulmonary contusion, leading to a significant reduction in the duration of ventilatory support. Secondary stabilization is recommended in patients with pulmonary contusion showing paradoxical movement of the chest wall during weaning from the respirator.

Adult↗
PubMed1996

[Penetrating wounds of the thorax].

From January 1989 to December 1993 at the Institute of Clinical Surgery of the University of Perugia, 5 patients were under observation for penetrating chest injuries. Two of them had show-wounds, one a slash, one a stabbing and slash and one a cutting blow. One of the patients with shot-wounds died on the operating table from a haemorrhage while the other was saved by surgery. One patient successfully underwent surgery for loss of tissue in the thorax walls. Another had a mini-thoracotomy plus lung suture which were successful. Finally, in the patient with a slash in the front region of the thorax and a slight pneumothorax, we inserted a chest thorax tube and so obtained a complete re-expansion of the lung. Total mortality was 20%. Surgical exploration of the thorax we believe is necessary wherever there is a risk of haemorrhage or possible lung damage requiring only surgery. According to many authors, video-thoracoscopy has the advantage of a reliable diagnosis and above all, enable us to repair lung wounds without opening the thorax. In one of our patients we could have avoided the mini-thoracotomy and used thoracoscopy to repair the lung damage.

Adult↗
PubMed2004

REML estimates of genetic parameters of sexual dimorphism for wing and thorax length in Drosophila melanogaster.

Restricted maximum likelihood was used to estimate genetic parameters of male and female wing and thorax length in isofemale lines of Drosophila melanogaster, and results compared to estimates obtained earlier with the classical analysis of variance approach. As parents within an isofemale line were unknown, a total of 500 parental pedigrees were simulated and mean estimates computed. Full and half sibs were distinguished, in contrast to usual isofemale studies in which animals were all treated as half sibs and hence heritability was overestimated. Heritability was thus estimated at 0.33, 0.38, 0.30 and 0.33 for male and female wing length and male and female thorax length, respectively, whereas corresponding estimates obtained using analysis of variance were 0.46, 0.54, 0.35 and 0.38. Genetic correlations between male and female traits were 0.85 and 0.62 for wing and thorax length, respectively. Sexual dimorphism and the ratio of female to male traits were moderately heritable (0.30 and 0.23 for wing length, 0.38 and 0.23 for thorax length). Both were moderately and positively correlated with female traits, and weakly and negatively correlated with male traits. Such heritabilities confirmed that sexual dimorphism might be a fast evolving trait in Drosophila.

Animals↗