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Magnetic resonance imaging is a valuable modality of extreme flexibility for specific problem-solving capability in the thorax. This article reviews MR applications in the imaging of great vessels, which are currently the most important applications in the thorax; other established applications in the thorax; and pulmonary functional MR imaging.
The quality of thorax and pelvis transmission scans and therefore of attenuation correction in PET depends on patient thickness and transmission rod source strength. The purpose of the present study was to assess the feasibility of using count-based transmission scans, thereby guaranteeing more consistent image quality and more precise quantification than with fixed transmission scan duration. First, the relation between noise equivalent counts (NEC) of 10 min calibration transmission scans and rod source activity was determined over a period of 1.5 years. Second, the relation between transmission scan counts and uniform phantom diameter was studied numerically, determining the relative contribution of counts from lines of response passing through the phantom as compared with the total number of counts. Finally, the relation between patient weight and transmission scan duration was determined for 35 patients, who were scanned at the level of thorax or pelvis. After installation of new rod sources, the NEC of transmission scans first increased slightly (5%) with decreasing rod source activity and after 3 months decreased with a rate of 2-3% per month. The numerical simulation showed that the number of transmission scan counts from lines of response passing through the phantom increased with phantom diameter up to 7 cm. For phantoms larger than 7 cm, the number of these counts decreased at approximately the same rate as the total number of transmission scan counts. Patient data confirmed that the total number of transmission scan counts decreased with increasing patient weight with about 0.5% kg(-1). It can be concluded that count-based transmission scans compensate for radioactive decay of the rod sources. With count-based transmission scans, rod sources can be used for up to 1.5 years at the cost of a 50% increased transmission scan duration. For phantoms with diameters of more than 7 cm and for patients scanned at the level of thorax or pelvis, use of count-based transmission scans is feasible and results in statistically more consistent transmission scans as compared with fixed transmission scan duration.
We studied thorax formation in Drosophila melanogaster using a misexpression screen with EP lines and thoracic Gal4 drivers that provide a genetically sensitized background. We identified 191 interacting lines showing alterations of thoracic bristles (number and/or location), thorax and scutellum malformations, lethality, or suppression of the thoracic phenotype used in the screen. We analyzed these lines and showed that known genes with different functional roles (selector, prepattern, proneural, cell cycle regulation, lineage restriction, signaling pathways, transcriptional control, and chromatin organization) are among the modifier lines. A few lines have previously been identified in thorax formation, but others, such as chromatin-remodeling complex genes, are novel. However, most of the interacting loci are uncharacterized, providing a wealth of new genetic data. We also describe one such novel line, poco pelo (ppo), where both misexpression and loss-of-function phenotypes are similar: loss of bristles and scutellum malformation.
The purpose of this set of two articles is to illustrate the source and direction of lymphatic drainage in the thorax on axial CT schematics. The first article describes the upper thorax. The second article will describe the lower thorax. The nodal groups are given conventional anatomic names and the corresponding terminology of the American Thoracic Society. Arrows indicate the direction of the flow. The region or organ drained is color-coded, and nodes that receive lymph from each area are assigned appropriately colored boxes. Major drainage patterns are also described. This information can be used to assess a suggestive lymph node by tracing it to the region of drainage and looking for pathological lesions. Alternatively, one may extrapolate the potential drainage routes of a tumor and scrutinize specific sites for nodal metastases.
The purpose of this set of 2 articles is to illustrate the source and direction of lymphatic drainage in the thorax on axial computed tomographic (CT) schematics. The first article describes the upper thorax. This article describes the lower thorax. The nodal groups are given conventional anatomic names and the corresponding terminology of the American Thoracic Society. Arrows indicate the direction of the flow. The region or organ drained is color-coded, and nodes that receive lymph from each area are assigned appropriately colored and numbered boxes. Major drainage patterns are also described. This information can be used to assess a suspicious lymph node by tracing it to the region of drainage and looking for pathology. Alternately, one may extrapolate the potential drainage routes of a tumor and scrutinize specific sites for nodal metastases.
To investigate the influence of changes in thorax and lung compliance on ventilation during distal High Frequency Jet Ventilation (HFJV), similar ventilator settings were compared before and after changing the compliance in two groups of anaesthetized mongrel dogs. Each period of distal HFJV was preceded by adequate Intermittent Positive Pressure Ventilation (IPPV) to assure a start with baseline values. In Group 1 (n = 7), thorax compliance was changed by chest strapping, while in Group 2 (n = 7) lung compliance was changed by inducing acute lung injury by injection of oleic acid into the right atrium. Gas flow distribution in the ventilatory circuit during distal HFJV was determined before and after the changes in compliance were induced. Comparing similar ventilator settings during distal HFJV in the same dog, a decrease in lung or thorax compliance led to changes in gas flow distribution in the ventilatory circuit. Entrainment was decreased and bypass increased with a negative effect on the gas volume entering the lungs and on gas exchange. The results indicate that distal HFJV should be regarded as pressure-limited ventilation.
We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four lung cancer patients were monitored by tracking external markers placed on the thorax. A 4D-CT acquisition was performed using a "step-and-shoot" technique, in which computed tomography (CT) projection data were acquired over a complete respiratory cycle at each couch position. The period of each CT acquisition segment was time stamped with an "x-ray ON" signal, which was recorded by the tracking system. 4D-CT data were then sorted into 10 groups, according to their corresponding phase of the breathing cycle. 4D-PET data were acquired in the gated mode, where each breathing cycle was divided into ten 0.5 s bins. For both CT and PET acquisitions, patients received audio prompting to regularize breathing. The 4D-CT and 4D-PET data were then correlated according to respiratory phase. The effect of 4D acquisition on improving the co-registration of PET and CT images, reducing motion smearing, and consequently increase the quantitation of the SUV, were investigated. Also, quantitation of the tumor motions in PET, and CT, were studied and compared. 4D-PET with matching phase 4D-CTAC showed an improved accuracy in PET-CT image co-registration of up to 41%, compared to measurements from 4D-PET with clinical-CTAC. Gating PET data in correlation with respiratory motion reduced motion-induced smearing, thereby decreasing the observed tumor volume, by as much as 43%. 4D-PET lesions volumes showed a maximum deviation of 19% between clinical CT and phase- matched 4D-CT attenuation corrected PET images. In CT, 4D acquisition resulted in increasing the tumor volume in two patients by up to 79%, and decreasing it in the other two by up to 35%. Consequently, these corrections have yielded an increase in the measured SUV by up to 16% over the clinical measured SUV, and 36% over SUV's measured in 4D-PET with clinical-CT Attenuation Correction (CTAC) SUV's. Quantitation of the maximum tumor motion amplitude, using 4D-PET and 4D-CT, showed up to 30% discrepancy between the two modalities. We have shown that 4D PET/CT is clinically a feasible method, to correct for respiratory motion artifacts in PET/CT imaging of the thorax. 4D PET/CT acquisition can reduce smearing, improve the accuracy in PET-CT co-registration, and increase the measured SUV. This should result in an improved tumor assessment for patients with lung malignancies.
To test the idea that the lateral intercostal muscles may be more suited to aid in rotational than respiratory movements of the thorax, we inserted bipolar fine-wire electrodes in external and internal intercostal muscles in the right midaxillary line in nine sitting subjects and examined the pattern of contraction of these muscles during voluntary axial rotations of the thorax (30-35 degrees), resting breathing, and CO2-induced hyperpnea. The right external intercostal muscles were strongly recruited in rotations to the left but were not active in rotations to the right. In contrast, the right internal intercostal muscles were active in rotations to the right but not in rotations to the left. Rotations completed in 1 or 2 s were associated with an early burst of electromyographic activity, followed by a low plateau that persisted while the rotation was held. Rotations made very gradually over 5-10 s were associated with gradually rising electromyographic activity. The amplitude of activity recorded during 30-35 degrees rotations was equivalent to that measured when minute ventilation was increased by CO2 to 50 l/min. We conclude that the lateral intercostal muscles have a major role in producing axial rotations of the thorax.
The nuclear proteins Spalt and Spalt-related belong to a conserved family of transcriptional regulators characterised by the presence of double zinc-finger domains. In the wing, they are regulated by the secreted protein Decapentaplegic and participate in the positioning of the wing veins. Here, we identify regulatory regions in the spalt/spalt-related gene complex that direct expression in the wing disc. The regulatory sequences are organised in independent modules, each of them responsible for expression in particular domains of the wing imaginal disc. In the thorax, spalt and spalt-related are expressed in a restricted domain that includes most proneural clusters of the developing sensory organs in the notum, and are regulated by the signalling molecules Wingless, Decapentaplegic and Hedgehog. We find that spalt/spalt-related participate in the development of sensory organs in the thorax, mainly in the positioning of specific proneural clusters. Later, the expression of at least spalt is eliminated from the sensory organ precursor cells and this is a requisite for the differentiation of these cells. We postulate that spalt and spalt-related belong to a category of transcriptional regulators that subdivide the thorax into expression domains (prepattern) required for the localised activation of proneural genes.
The left ventricular muscle volume (LVMV) was determined echocardiographically and the radius of the circle with equal circumference to the thorax (R1) was calculated from thorax-circumference in 688 children as a part of the Shimane Heart Study. correlation of the summed precordial voltage (SV1 + RV5) with LVMV was not close (r = 0.377 in boys and -0.095 in girls). The precordial voltage (SV1 + RV5) was corrected by the square of R1 to compensate for the diminution of electrical potential by distance. Correlation between (R1) 2 x (SV1 + RV5) and LVMV was good in boys (r = 0.681) and relatively good in girls (r= 0.554). This fact indicates that LVMV can be predicted from ECG and anthropometric measurements of thorax without using echocardiography. Therefore, (R1) 2 x (SV1 + RV5) seems to have clinical applicability as the index of LV size, if the differences in (R1) 2 x (SV1 + RV5) and in the correlation coefficient between both sexes are clarified further.
The causative mechanisms of mitral valve prolapse (MVP) were evaluated in 58 patients with progressive muscular dystrophy (PMD). Two possible causes, 1) left ventricular (LV) dysfunction and 2) thoracic spine and thorax deformities were assessed. Patients were classified into three groups by echocardiographic findings. Group 1: 31 patients without MVP, group 2: 11 patients with MVP confirmed only by M-mode echocardiogram, group 3: 16 patients with MVP confirmed by both two-dimensional and M-mode echocardiograms. LV functions evaluated by systolic time intervals and fractional shortening showed no significant differences among the three groups. Scoliosis of the thoracic spine was not related to the incidence of MVP. Lordotic or straight spines were found in 32.3%, 100%, 93.8% of cases in group 1, group 2 and group 3, respectively, and the incidences of MVP in cases with kyphosis, straight spine and lordosis were 4.8%, 66.7% and 77.8%, respectively. The shape of the thorax as evaluated by the ratio of anteroposterior internal diameter to transverse diameter was more flattened in groups 2 and 3 than in group 1. From these results, we concluded that LV dysfunction was not related to the incidence of MVP and that the lordotic or straight spine and the flattened thorax were supposed to be the major factors in the occurrence of MVP in PMD.
In this paper, the forward problem of electrocardiogram(ECG) has been calculated by means of numerical simulating techniques. Firstly, It is focused on the effects of organs and tissues within the thorax on the body surface potentials under a 2-D cross section of thorax in terms of finite element method (FEM). To check the effect of skeletal muscle layers on ECG, the simulating computation of ECG, by a method combining FEM with boundary element method (BEM), has been carried out in terms of a 3-D thorax model.
The anatomy of the cutaneous nerves innervating the canine thorax and abdomen was investigated by gross dissection of 38 dogs. Additionally, the cutaneous areas innervated by the thoracic and abdominal cutaneous nerves were mapped in a 2nd group of 33 barbiturate-anesthetized male dogs, using electrophysiologic techniques. The skin of the thorax was innervated by dorsal cutaneous branches, lateral cutaneous branches, and ventral cutaneous branches of the spinal nerves. The dorsal cutaneous branches were branches of the dorsal primary branches of spinal nerves C6 and T2 through T11. The lateral cutaneous branches were branches of the ventral primary branches of spinal nerves T2 through T12. The ventral cutaneous branches were branches of the ventral primary branches of spinal nerves T2 through T10. The skin of the abdomen was innervated by dorsal and lateral cutaneous branches of spinal nerves T12 through L3 (and occasionally L4). The cutaneous areas of the dorsal cutaneous branches occupied the dorsal half of the scapular and thoracic regions and the dorsal 2/5 of the abdominal region. The cutaneous areas of the lateral cutaneous branches covered the major portion of the ventral half of the thorax and the ventral 3/5 of the abdomen. The cutaneous areas of the ventral cutaneous branches occupied the axilla and the ventral part of the thoracic wall.
Artificial selection for increasing and decreasing Drosophila thorax length was carried out over 20 generations. Chemical mutagen, dimethylsulfate (DMS) was regularly applied to enhance genetic variation in selected lines. It was determined that under the influence of mutagen the efficiency of selection for decreasing thorax length was much higher, while selection course for increasing thorax length was not affected significantly. Regression coefficient of responses to selection, general for males and females, was equal to b = -0.035 +/- 0.004 for lines of negative direction of selection when the mutagen was applied and -b = -0.023 +/- 0.004 without mutagenesis; for lines of positive direction b = 0.026 +/- 0.005 and b = 0.024 +/- 0.005. Fitness component variation by artificial selection was studied. A complex correlation was detected between direction of selection, the shift value of model quantitative character and fitness component variation by selection. The main factor stimulating a sharp drop of average fitness of lines appeared to be the influence of directional artificial selection. The regular treatment by a moderate dose of the mutagen did not affect markedly the average fitness variation of selected lines.
In a group of 317 newborns, measurements of the perimeter of the arm and the thorax were taken as an indicator of low birth weight. The perimeters of both the arm and the thorax had a high correlation with low birth weight (LBW) (0.88-0.80 respectively). In the sample group, the cut-off point to define low birth weight in the case of perimeter of the arm was 9 cm and was 29-30 cm for perimeter of the thorax. Applying these measurements facilitates early detection and treatment of low birth weight babies who are at risk for infant mortality in situations where it is not possible to weigh the baby at birth.
Current methods of four-dimensional (4D) CT imaging of the thorax synchronise the acquisition with a respiratory signal to restrospectively sort acquired data. The quality of the 4D images relies on an accurate description of the position of the thorax in the respiratory cycle by the respiratory signal. Most of the methods used an external device for acquiring the respiratory signal. We propose to extract it directly from thorax cone-beam (CB) CT projections. This study implied two main steps: the simulation of a set of CBCT projections, and the extraction, selection and integration of motion information from the simulation output to obtain the respiratory signal. A real respiratory signal was used for simulating the CB acquisition of a breathing patient. We extracted from CB images a respiratory signal with 96.4% linear correlation with the reference signal, but we showed that other measures of the quality of the extracted respiratory signal were required.
Thorax injuries may be divided etiologically into blunt and penetrating types, depending on the nature of the insult. In European practice, the former predominates by far, and in only about 5% of cases thoracotomy provides the necessary thorax drainage. Morbidity in this type of injury typically involves concomitant lung contusion, sometimes with fatal acute respiratory distress syndrome. In these cases, special ventilation forms, optimal reduction of pain, and organ replacement are the decisive therapeutic methods. In contrast, about 80% of penetrating trauma to the thorax require prompt transpleural or trans-sternal surgery, depending on the type of injury. Emergency first aid must follow the principle of "scoop and run". Each minute elapsed until emergent thoracotomy can be decisive to survival in these cases, and the fastest possible transport from the place of injury takes priority over time-consuming stabilization.
The detection of distant metastases or synchronous primary tumours at initial presentation, or at recurrence in patients with head and neck squamous cell carcinoma (HNSCC), frequently alters the selection of therapy in these patients. A number of series report appreciably high rates for these lesions. This study evaluated 108 computed tomography (CT) scans and chest radiographs (CXR) of the thorax, in 80 patients presenting with HNSCC over a 4 year period. There were three clinical settings; (a) at original diagnosis n = 61, (b) clinical evidence of local/regional recurrence n = 19 (c) suspicion of recurrence due to neck symptomatology n = 28. CT thorax detected two out of 61 (3%) distant metastases at the initial diagnosis stage (both were either stage III or IV) and one out of 19 (5%) patients evaluated at the time of loco/regional recurrence. CXR failed to reveal evidence of pulmonary metastases in the two patients at initial diagnosis stage, but correctly identified pulmonary metastases in the loco-regional recurrence patient. There was no thoracic malignancy detected in the surveillance CT scans, and no synchronous second primary tumour detected during the study. CT is known to be more sensitive than conventional CXR in detecting thoracic pathology in HNSCC patients, however, we feel CT is of limited value in stage I or II disease. We no longer carry out routine staging CT scans of the thorax in patients presenting with stage I or II HNSCC, or with neck symptomatology with no clinical evidence of recurrence.