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At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Detailed model of the thorax as a volume conductor based on the visible human man data.

A large number of computerized conductivity models of the human thorax have been created to study bioelectric phenomena in human beings. Devised models have varied greatly in the level of anatomical detail incorporated thus restricting the accuracy and validity of conducted simulations. This paper introduces a highly detailed anatomically accurate three-dimensional computer model of the conductive anatomy of the human thorax for calculating electric fields generated by equivalent bioelectric sources and different externally applied sources. The anatomy of the devised model is based on high resolution colour cryosection images of the US National Library of Medicine's Visible Human Man data set and is comprised of more anatomical detail than prior computer models. The model is based on the finite difference method and is readily applicable for the analysis of a wide range of biomedical field problems, such as electrocardiography, impedance cardiography, tissue stimulations, and especially, in development of measurement systems.

Anatomy, Cross-Sectional↗
PubMed2002

[Method of preventing aliasing artifacts of arms using electromagnetic-wave shield fabric on coronal images of the thorax or abdomen by fast breath-hold MR imaging].

The purpose of this study is to examine an antialiasing method in the breath-hold coronal imaging of the thorax or abdomen. This paper reports a new method of preventing the aliasing artifacts of arms using "Hertz II" as a electromagnetic-wave shield fabric (ESF),which is a very thin and flexible special synthetic fabric. In this study, the ESF method was compared with various conventional preventive measures. Temperature changed around the ESF was also measured by using a fiber optic temperature measurement system during the MR scanning procedure. In addition, the ESF method was tried to use for scanning with some volunteers and some patients in clinical examinations. The results of this study showed that the ESF method could efficiently prevent the aliasing of arms in the MR images. Furthermore, safety of the subjects was hardly affected by the ESF method during MR imaging. Therefore, we concluded that the ESF method was an effectual antialiasing method in the imaging of the thorax or abdomen by using the fast breath-hold scanning.

Abdomen↗
PubMed1976

[Unviable micromelic dwarfism: a syndrome with dystrophy of the thorax and polydaktyly type Saldino-Noonan (author's transl)].

Besides classical achondroplasia various severe osteochondrodysplastic disorders have been differentiated in recent years. Their most important features include obligatory perinatal mortality, severe dystrophy of the thorax and shortening of tubular bones. Additionally some of these syndromes present visceral malformations, cleft-lip, and malformations of the genitals. A detailed case report of a patient is given. Various features: dystrophy of the thorax, micromelia, postaxial polydactyly, metaphyseal dysplasia, malformations of the great vessels, and polcystic kidney suggest the classification as short rib-polydactyly syndrome, type Saldino-Noonan.

Aorta↗
PubMedDate not supplied

Thorax: new millennium vascular imaging.

In recent years the technological development of computed tomography (CT) and magnetic resonance (MR) has promoted new improvements in diagnosis by means of imaging. In particular the introduction of multislice CT and MR angiography (MRA) has broadened the non-invasive diagnostic possibilities in the vascular study of the thorax. The new technological developments of CT and MR enable functional studies as well. Recent studies have demonstrated that CT and MR are as accurate in finding the vascular anomalies as digital subtraction angiography, while they are more precise in recognising possible associated pathologies which modify therapeutic treatment (for example of the trachea, bronchi, oesophagus etc.). There are many vascular structures in the thorax which need to be considered (aorta, pulmonary and coronary arteries, pulmonary veins, vena cava). The field of associated pathologies is also broad, and includes congenital vascular anomalies, vascular malformations, aorta dissection, vascular compression syndromes, atherosclerotic stenosis or occlusions, and pulmonary embolism. In pulmonary embolism some authors have demonstrated the utility of CT, in showing pulmonary segmental perfusion defects, and MRA, in identifying sub-segment pulmonary embolism. In this paper we analyse the most important CT and MR applications for the study of vascular thoracic diseases and compare them with other diagnostic techniques. We also evaluate the morpho-functional capabilities of CT and MR in this field.

Humans↗
PubMed2006

[Changes in thorax-lung compliance during general anesthesia with mechanical ventilation in response to various intraoperative maneuvers].

BACKGROUND: The author evaluated and compared changes in the thorax-lung compliance (C) of the patients under general anesthesia and mechanical ventilation in response to various intraoperative maneuvers. METHODS: With ethics committee approval, 60 ASA physical status I and II patients undergoing elective surgery were studied. The author compared C on supine position with no maneuver as control, with C with cephalad liver retraction by the abdominal retractor (AR), pneumoperitoneum by intraabdominal pressure of 12 mmHg (LS), abdominal wall lift (AL), sternal splitting (SS), and sternum lift (SL) position (BMI<or=25kg x m(-2)). Following induction of anesthesia the parameters were measured and recorded. Patients were mechanically ventilated with a tidal volume of 9 ml x kg(-1) and a respiratory rate of 8 breaths per minutes. Statistical analysis was performed with ANOVA and P<0.01 was considered significant. RESULTS: In the AR and LS groups, C decreased significantly. In the AL, SS and SL groups, C increased significantly. CONCLUSIONS: The thorax-lung compliance of the AL, SS and SL maneuver groups were physiologically superior to supine position for normal weight patients and these maneuvers avoid derangement of pulmonary functions.

Aged↗
PubMed1991

Anatomy of the thorax and shoulder girdle displayed by magnetic resonance imaging.

In 1971, radiographic anatomy of the human body was added to the gross anatomy course at UCLA. Radiographic contrast studies and plain anatomical displays were formulated into teaching packages for all organ systems. Residents presented each package to first-year medical students in the dissection laboratory to augment the teaching of anatomy. In November 1984, magnetic resonance imaging was instituted in the radiology department. Imaging the chest produced coronal and axial planes which displayed the muscles and soft tissues of the thorax. In 1986, the authors presented their study of MR anatomy of the chest and shoulder girdle to the American Association of Anatomists. The purpose of this presentation is to demonstrate the anatomy of the thorax and shoulder girdle as displayed by magnetic resonance, correlated with regional anatomy, with emphasis on soft tissue structures.

Humans↗
PubMedDate not supplied

Use of lung-thorax transverse area ratio in the antenatal evaluation of lung hypoplasia in congenital diaphragmatic hernia.

For evaluation of lung hypoplasia in congenital diaphragmatic hernia (CDH), we measured lung-thorax transverse area ratio (LT ratio), which was defined as the area of bilateral lung profiles divided by the profile area of thorax at the level of the four-chamber view of the heart, using fetal ultrasonography. LT ratio in cases with CDH was lower than that in the control group and related well to the postnatal respiratory condition. Measurement of LT ratio using fetal ultrasonography may be useful in predicting the degree of lung hypoplasia in fetuses with CDH.

Female↗
PubMed1978

[Method of performing an autopsy without cutting into the thorax or dissecting the ribs].

Two variants of autopsy of cadavers without cutting of the thorax and dissection of the ribs are described. The method is principally based on the transversal cutting of the abdominal wall alongside both hypochondria, severing of the diaphragm and exposure of a complex of organs (after preliminary removal of the intestine and spleen). In the first variant of autopsy, the upper part of the complex is crossed in the thorax at the level of the upper aperture of the thoracic cavity, leaving the organs of the neck without autopsy. In the second variant, no such crossing is done and the complex is removed together with the organs of the neck and the tongue (that is, the autopsy is complete). To separate the latter, an additional transversal supraclavicular cut about 10 cm in length is made. The advantages of these variants lie in the cosmetic effect.

Autopsy↗
PubMed1993

Phase-contrast magnetic resonance angiography in the abdomen and thorax.

Clinical applications of phase-contrast MR angiography have been focused mainly on the head and neck, and its applications to the thorax and abdomen are still limited. This technique, however, has several unique uses that can be used to good effect. This articles examines the practical uses of phase-contrast MR angiography in the abdomen and thorax.

Abdomen↗
PubMedDate not supplied

Motions of the head and thorax during neck manipulations.

OBJECTIVE: The purpose of this study was to determine the amplitudes and variations of preload positioning and displacements of the head and thorax during spinal manipulative therapy (SMT) applied to C2. DESIGN: This experimental study measured the biomechanics of SMT applied to C2. SETTING: Biomechanics Laboratory, Mechanical Engineering and Applied Mechanics, University of Michigan and Spinal Ergonomics and Joint Research Laboratory, National College of Chiropractic. PARTICIPANTS: Eighteen healthy volunteers from the University of Michigan and the National College of Chiropractic were manipulated by a total of eight experienced chiropractic physicians licensed in the state in which they participated. INTERVENTION: Sixty-six Direct Break (DB) and twenty-three Rotary Break (RB) diversified procedures were administered to C2. Randomization of the DB was made on two variables, direction and intended load intensities. The RB was administered only from the right by each physician. MAIN OUTCOME MEASURES: Linear and angular displacement time histories for the head and thorax mass centers were monitored during the preload setup of each procedure and the dynamic delivery of the treatment procedures. CONCLUSIONS: DB procedures were found to have sagittally symmetric positioning and displacements as a function of intended direction of the procedure. Both DB and RB methods consisted of preload positioning with head flexion. RB rotation and lateral bending preload positions approached the maximal voluntary ranges of motion for the upper cervical spine. Variations among procedures by one manipulator were approximately the same as for variations among manipulators. Data indicates that SMT procedures can be successfully modified to control amplitude and direction of body segment displacements that arise.

Adult↗
PubMed1994

[The usefulness of transcutaneous gas monitoring during hemorrhagic shock; discrepancy between the two transcutaneous gas tensions of anterior thorax and femur].

We measured transcutaneous gas tensions of both anterior thorax and femur. The differences between the two transcutaneous gas tensions were compared, as well as the relationship between the two transcutaneous and mixed venous blood gas tensions, in 10 dogs during hemorrhagic shock. The changes in femoral transcutaneous gas tensions correlated better with the changes in mixed venous gas tensions. The correlation between the two transcutaneous gas tensions were fairly good (oxygen tensions; r = .827, carbon dioxide tensions; r = .867). However, the discrepancy between the two gas tensions became greater in severe shock. Hence, oxygen tensions became smaller and carbon dioxide tensions became greater on femur than on anterior thorax. This indicates the possibility of "maldistribution of blood flow", which has already been detected between vital organs and skin, also exists between peripheral and central skin. Therefore, transcutaneous gas tensions should be monitored at peripheral skin, where gas tensions show greater changes and reflect systemic perfusion precisely than at central skin, during shock.

Animals↗
PubMed1993

[Biomechanical simulation of the effect of the Boston brace on a model of the scoliotic spine and thorax].

A biomechanical model was developed to investigate the immediate effect of the Boston brace on the spine and thorax of two scoliotic patients (12 year old females with identical lumbar curves of 37 degrees and thoracic curves of 32 degrees and 25 degrees). This model is an improvement of Stokes model and incorporates several modifications concerning the modelling of costo-vertebral and costo-transverse joints. Forces generated by braces on the thorax were measured by pressure sensors and used as input into the finite element model. The deformed models were compared to the geometry of the same patients wearing their brace and with Stokes model. Concordance of results supports the modelling method. Differences between Stokes and improved models were observed. However, because of the small amount of patients included in this study, it is not possible to conclude on the effect of the modelling improvements.

Braces↗
PubMed1995

[Geometrical modeling of the spine and the thorax for the biomechanical analysis of scoliotic deformities using the finite element method].

In order to study the biomechanical behavior of the whole human spine and thorax, as well as orthopaedic treatment effects, a new generation model is proposed, which includes a precise functional representation of the posterior part of the spine, while respecting computational capabilities. This paper presents the geometrical aspects of this model. The latter is built using an hybrid method which combines steroradiographic 3-D reconstructions of the spine and thorax [1] to serial CT scan 3-D reconstructions of typical human vertebrae and sternum [4] and published morphometric data of ribs [2, 3]. These anatomical structures were deformed in order to fit as well as possible the personalized data of scoliotic patients using geometrical transformations as well as interpolation or extrapolation techniques. In the posterior part, articular facets are modelled and parameterized as elementary surface shapes (plane, cylinder, sphere). For the articular facet geometry of a given normal subject, results revealed that the zygapophyseal facets are better represented by planes for T1 to T11 and by portions of cylinders for T12 to L5, which is in concordance with the literature [5, 6]. Evaluation of this modelling approach was done on 2 cadaveric vertebral segments. Parametric data obtained from the model were compared to precise measurements done on the vertebrae using a 3-D digitizer, and concordance was found. These personalized geometric informations were then used to build a finite element model [7], which will be useful to study scoliotic deformities as well as personalized orthopaedic treatments.

Humans↗
PubMed1996

[Hydatic cysts of the liver ruptured into the thorax. Diagnostic and therapeutic aspects].

Hydatic cysts of the liver can rupture into the thorax. The aim of this work was to demonstrate how abdominal access can be used in most cases. We report 44 cases of hydatic cysts which ruptured into the thorax among a series of 1411 hydatic cysts of the liver operated between 1974 and 1995. Abdominal ultrasound and chest x-ray provided the diagnosis preoperatively in 35/42 operated cases (one case of spontaneous elimination of a hydatic membrane via a cutaneous orifice and one case of preoperative death). Thoracophrenolaparotomy was used in 12 cases, thoracotomy with laparotomy in 6, thoracotomy alone in 5 and laparotomy alone in 19. Pulmonary resections were performed in 18 cases. No procedure could be performed in one patient who died at the beginning of surgery. A breach in the diaphragm was repaired in 41 cases. The dome of the cyst was resected in 29 cases and complete pericystectomy was performed in 12. There were 7 post-operative deaths. There were no deaths in the abdominal access patients. All emergency problems were controlled with abdominal access. Thoracic access was reserved for specific cases.

Adolescent↗
PubMed1979

The thorax as the initial site for systemic relapse in malignant melanoma: a prospective survey of 324 patients.

Thirteen of 324 patients with malignant melanoma followed during a 24 month period experienced dissemination. The thorax was the initial site for relapse in 12, all of whom were asymptomatic. Ten gave no evidence of extrathoracic disease. Retrospective analysis of previous x-rays originally interpreted as negative revealed metastases in 33%. Life table analysis demonstrated a significantly longer survival for the subset with isolated intrathoracic metastases treated surgically than for their counterparts with metastases no longer amenable to surgery and treated by other modalities. We conclude that the thorax is the site of predilection for initial systemic relapse in malignant melanoma, that detection of early, surgically resectable metastases correlates with longer patient survival, and that routine chest roentgenography is inadequate in reliably uncovering such early disease. These data suggest the potential value of more vigorous radiographic surveillance (with either computed tomography or conventional full lung tomography) in patients at high risk for relapse.

Adult↗
PubMed1981

Application of computed tomography in differential diagnosis of radiographic opacities in the lower thorax and upper abdomen.

The differential diagnosis of radiographic homogeneous opacities in the lower thorax and upper abdomen is very often a dilemma for radiologists. Recently we have encountered the following 8 cases in which the correct radiologic diagnoses (confirmed pathologically) were made only by computed tomography: pyogenic liver abscesses (2 cases), subphrenic hematoma, pancreatitis with pseudocyst, adrenal cortical carcinoma, ovarian carcinoma with liver metastasis, lower lobe pulmonary infarction, and metastatic breast cancer in the peri-esophageal region. The CT findings displayed not only the anatomic location and extent of these lesions but also the unique characteristics of many of the pathologic processes that produce these otherwise nonspecific radiographic opacities. It is our purpose here to demonstrate the CT findings in such patients and to advocate CT study as a very effective diagnostic modality in those patients who present with radiographic homogeneous opacities in the lower thorax and upper abdomen.

Adrenal Gland Neoplasms↗
PubMed1990

The influence of altered head, thorax and pelvis mass on the postnatal development of the air-righting reaction in albino rats.

The experiments were performed on 18 albino newborn rats of both sexes. The postnatal development of the air-righting-reaction (ARR) of the rats was tested for 4 different falling heights (30, 40, 50 and 60 cm) with 3 different loading conditions: artificial alteration of the head, thorax and pelvis mass, respectively. The reaction was analyzed in terms of a three-segment model of the rat (three rotatable parts: head-thorax-pelvis with only one degree of freedom between successive segments). Loading of the head resulted in a delayed development of the first phase of the ARR, whereas loading of the trunk or pelvis slowed the second phase of development. In general, it appears that loading of a body segment results in a delayed development of the rotation of that segment during free fall. Furthermore, loading of a caudal region was associated with an earlier rotation of cranial segments. The completion of the ARR maturation process showed no dependency on either the location or the size of the load, suggesting that the postnatal development of the ARR is pre-programmed.

Animals↗
PubMed1995

Time-dependent changes in electrical resistance of the intact trunk, thorax and abdomen of rats during the first 21 days post mortem.

Electrical resistance of the intact trunk, thorax and abdomen was determined sequentially in each of eight rat cadavers maintained at constant temperature. All electrodes applied to each cadaver were left in situ for the duration of the 21-day postmortem period. Trunk, thoracic and abdominal resistances increased (on average) from 337 +/- 31, 174 +/- 27 and 163 +/- 22 omega 1 h after death, to peak values of 567 +/- 46, 333 +/- 36 and 254 +/- 33 omega at 2, 3 and 1 days post mortem, respectively. Thereafter, all resistances decreased progressively with increasing time since death, reaching values of 294 +/- 39 omega (trunk), 173 +/- 33 omega (thorax) and 121 +/- 19 omega (abdomen) at 21 days post mortem. These changes are believed to reflect progressive postmortem decreases in the resistivities of the body segments studied.

Animals↗