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At least 343 records · Page 19Linked to original sources
PubMed2004

Electrocardiographically gated 16-section CT of the thorax: cardiac motion suppression.

Thirty patients underwent 16-section multi-detector row computed tomographic (CT) angiography of the thorax with retrospective electrocardiographic gating. Institutional review board approval was obtained for retrospective analysis of CT scan data and records; patient informed consent was not required. Images reconstructed at six different time points (0%, 20%, 40%, 50%, 60%, 80%) within the R-R interval on the electrocardiogram were analyzed by two radiologists for diagnostic quality, to identify suitable reconstruction intervals for optimal suppression of cardiac motion. Five regions of interest (left coronary artery, aortic root, ascending and descending aorta, pulmonary arteries) were evaluated. Best image quality was achieved by referencing image reconstruction to middiastole (50%-60%) for the left coronary artery, aortic root, and ascending aorta. The pulmonary arteries are best displayed during mid- to late diastole (80%).

Adult↗
PubMed2005

Object-specific attenuation correction at SPECT/CT in thorax: optimization of respiratory protocol for image registration.

Institutional review board approval was obtained for multiple imaging examinations in healthy volunteers and patients and for the analysis of images. The purpose of the study, and the risks associated with radiation exposure with regard to stochastic effects that might result in cancer and/or genetic mutations, were explained to all subjects, and all questions from subjects were answered. Each subject provided written informed consent. The purpose of the study was to prospectively determine the respiratory protocol at computed tomography (CT) that results in the best registration of CT images with images acquired at single photon emission computed tomography (SPECT) in the thorax. Errors of registration between myocardial SPECT images and CT images obtained with different respiratory protocols (postinhalation breath hold, postexhalation breath hold, and free breathing) in 13 healthy subjects were compared. CT scans obtained with free breathing and postexhalation breath hold better matched SPECT images than did those obtained with postinhalation breath hold (one-way analysis of variance, P < .01). Fewer SPECT/CT images showed artifacts with registration performed by using internal landmarks (four, two, and one of 13 images with postinhalation breath-hold, postexhalation breath-hold, and free-breathing protocols, respectively) than with registration performed by using external markers (nine, four, and two of 13 images). CT data acquisition with a free-breathing or postexhalation breath-hold protocol and image registration by using internal landmarks are recommended for attenuation correction.

Adult↗
PubMed1995

Automatic patient-instruction devices in thin-section CT of the thorax: impact on image quality.

PURPOSE: To determine what influence automatic patient-instruction (API) devices have on image quality of chest computed tomographic (CT) scans and whether the qualitative outcome justifies their routine use. MATERIALS AND METHODS: Thin-collimation CT scans of two age- and sex-matched groups of 64 patients each were evaluated prospectively for the presence of breathing artifacts and for concomitant deterioration of image quality. Breathing commands in group 1 were given with the API device and in group 2 with technologist-performed patient instruction. Cardiac motion artifacts were not evaluated. The frequency of scans repeated owing to breathing artifact was determined. RESULTS: Image quality was worse in group 1 compared with that of group 2. The percentage of scans repeated was higher with API (38%) than without API (16%). CONCLUSION: API devices cannot be recommended for thin-section CT of the thorax. The large number of scans that must be repeated leads to a considerable increase in patient irradiation, scanning time, and cost.

Adult↗
PubMed1999

Lung cancer staging and management: comparison of contrast-enhanced and nonenhanced helical CT of the thorax.

PURPOSE: To determine whether contrast material-enhanced helical computed tomography (CT) of the thorax and upper abdomen changes the tumor stage and management compared with nonenhanced helical CT in patients with newly diagnosed lung cancer. MATERIALS AND METHODS: During 15 months, any patient in whom lung cancer was strongly suspected or newly diagnosed and who was scheduled for thoracic CT was considered eligible for the study. All patients underwent nonenhanced thoracic helical CT from the lung apices through the adrenal glands and then contrast-enhanced thoracic helical CT from the lung apices through the entire liver. Each study was read independently, and the thoracic radiologic stage was determined. Tissue sampling was performed and the final pathologic stage assigned. RESULTS: Ninety-six patients had a final pathologic diagnosis of lung cancer. There was agreement in stage between the nonenhanced and contrast-enhanced examinations in 92 of the 96 patients. In three patients, the tumor stage at nonehanced CT increased at contrast-enhanced CT, from IA to IIA (n = 1), IIB to IV (n = 1), and IIIB to IV (n = 1). In one patient, the tumor stage decreased from IIIB to IIB. There was no substantial change in management of any patient. CONCLUSION: The results suggest that contrast-enhanced thoracic CT through the liver for staging lung cancer rarely changes the tumor stage determined with nonenhanced CT through the adrenal glands and does not substantially influence management decisions.

Adult↗
PubMedDate not supplied

Small round cell tumors of the abdomen and thorax. Role of fine needle aspiration cytologic features in the diagnosis and differential diagnosis.

OBJECTIVE: To evaluate the role of cytomorphologic features in the diagnosis and differential diagnosis of small round cell tumor (SRCT) of the abdomen and thorax. STUDY DESIGN: During a period of six years (1985-1990), ultrasound/ computed tomography-guided fine needle aspiration cytology was performed on thoracic and abdominal/ pelvic masses in 899 cases. Slides were not available for review in 28 cases. Review of smears by one of the investigators (D.K.D.) in the remaining cases, which included 239 with intrathoracic and 632 with intraabdominal/pelvic masses, yielded 380 (43.6%) cases of malignancy. Of these, 71 (18.7%) cases were small round cell tumors. In 59 cases of SRCT the smears were found suitable for detailed assessment of cytomorphologic features. RESULTS: The 59 cases of small round cell tumors included 5 cases of neuroblastoma, 7 of hepatoblastoma, 4 of nephroblastoma, 1 of pulmonary blastoma, 2 of Ewing's sarcoma, 23 of non-Hodgkin's lymphoma (NHL), 15 of small cell anaplastic carcinoma (SCAC), 1 NHL/SCAC and 1 small round cell tumor (not otherwise specified). The frequencies of rosettes (60%) and filamentous/fibrillar matrix (100%) in neuroblastoma; acinar formation in hepatoblastoma (100%) and SCAC (93.3%); tubule formation in nephroblastoma (100%); lipid vacuoles (69.6%), exclusive noncohesive cells (95.7%) and lymphoglandular bodies (87%) in NHL; and nuclear molding (100%) and paranuclear blue inclusions (60%) in SCAC were significantly higher as compared to the rest of the SRCTs (P < .01 to < .0001). CONCLUSION: The various cytomorphologic features, alone or in conjunction with other cytologic features, and clinical/imaging findings are very useful in the diagnosis of specific types of SRCT.

Abdominal Neoplasms↗
PubMed1985

Optimal power generation by the left ventricle. A study in the anesthetized open thorax cat.

We studied the interaction of the left ventricle and the systemic arterial bed in the open thorax cat. In the steady state, the ventricle can be characterized by the pump function graph (i.e., the relationship between mean left ventricular pressure and mean outflow). From this pump function graph, the apparent source resistance of the heart is found. Apparent source resistance is defined as the ratio of the difference between maximal and actual mean left ventricular pressure, and mean outflow. The arterial system can be characterized by the ratio of mean aortic pressure and mean flow (peripheral resistance). The pressure and flow at which the heart operates is defined as the working point. We have investigated whether the ventricle in the intact cat is working optimally, i.e., that it cannot increase work output further at the end-diastolic volume, contractile state, and prevailing heart rate. This condition is considered as "matching" of ventricle and load. It could be shown that optimal power is transferred when the ratio of peripheral and apparent source resistance equals twice the ratio of mean aortic and mean left ventricular pressure (the matching principle). In four cats, we observed that mean aortic and mean left ventricular pressures are proportionally related. Mean external power (the time integral of the product of pressure and flow divided by cycle length) and steady power (the product of mean pressure and mean flow) were found to be proportional as well. These proportionalities allow for the calculation of peripheral resistance and mean external power from the pump function graph. Pump function graphs were determined in three groups: control (n = 9), atrial pacing (n = 8), and halothane (n = 5). We compared the ratio of peripheral and source resistance at the working point and at the point of optimal work output (expressed in steady ventricular power). It could be shown that, in all investigated groups, the power optimum and the working point coincide. It was concluded that circulatory control in the intact anesthetized cat keeps the ventricle at optimal work output under the conditions studied.

Animals↗
PubMed2006

Comparison of 18F SPECT with PET in myocardial imaging: a realistic thorax-cardiac phantom study.

BACKGROUND: Positron emission tomography (PET) imaging with fluorine-18 (18F) Fluorodeoxyglucose (FDG) and flow tracer such as Rubidium-82 (82Rb) is an established method for evaluating an ischemic but viable myocardium. However, the high cost of PET imaging restricts its wider clinical use. Therefore, less expensive 18F FDG single photon emission computed tomography (SPECT) imaging has been considered as an alternative to 18F FDG PET imaging. The purpose of the work is to compare SPECT with PET in myocardial perfusion/viability imaging. METHODS: A nonuniform RH-2 thorax-heart phantom was used in the SPECT and PET acquisitions. Three inserts, 3 cm, 2 cm and 1 cm in diameter, were placed in the left ventricular (LV) wall to simulate infarcts. The phantom acquisition was performed sequentially with 7.4 MBq of 18F and 22.2 MBq of Technetium-99m (99mTc) in the SPECT study and with 7.4 MBq of 18F and 370 MBq of 82Rb in the PET study. SPECT and PET data were processed using standard reconstruction software provided by vendors. Circumferential profiles of the short-axis slices, the contrast and viability of the inserts were used to evaluate the SPECT and PET images. RESULTS: The contrast for 3 cm, 2 cm and 1 cm inserts were for 18F PET data, 1.0 +/- 0.01, 0.67 +/- 0.02 and 0.25 +/- 0.01, respectively. For 82Rb PET data, the corresponding contrast values were 0.61 +/- 0.02, 0.37 +/- 0.02 and 0.19 +/- 0.01, respectively. For 18F SPECT the contrast values were, 0.31 +/- 0.03 and 0.20 +/- 0.05 for 3 cm and 2 cm inserts, respectively. For 99mTc SPECT the contrast values were, 0.63 +/- 0.04 and 0.24 +/- 0.05 for 3 cm and 2 cm inserts respectively. In SPECT, the 1 cm insert was not detectable. In the SPECT study, all three inserts were falsely diagnosed as "viable", while in the PET study, only the 1 cm insert was diagnosed falsely "viable". CONCLUSION: For smaller defects the 99mTc/18F SPECT imaging cannot entirely replace the more expensive 82Rb/18F PET for myocardial perfusion/viability imaging, due to poorer image spatial resolution and poorer defect contrast.

Journal Article↗
PubMed1998

Image processing and spiral CT of the thorax.

The data set of the thorax acquired by spiral CT is volumetric. Such data can be processed so that conventional axial sections are supplemented by reconstructed images, in an attempt to answer specific clinical questions. This review considers three reconstruction techniques: multiplanar reformation, three-dimensional rendering and sliding-thin slab reconstruction. Their relative benefits and limitations are considered, as are the implications of image processing in general.

Humans↗
PubMed2002

The experience and training of British general surgeons in trauma surgery for the abdomen, thorax and major vessels.

BACKGROUND: The report Better Carefor the Severely Injured [London: The Royal College of Surgeons of England and the British Orthopaedic Association; 2000] states that an experienced general surgeon trained in the techniques required to perform life-saving emergency surgery is vital in the management of major trauma. The experience and training of general surgeons in the UK in the management of trauma to the abdomen, thorax and major vessels has never been assessed. METHOD: Postal questionnaire sent to UK general surgical consultants and Higher Surgical Trainees (HSTs). RESULTS: A total of 854 (48%) questionnaires were completed. Of respondents, 85% believe that major trauma should be directed to hospitals that provide a dedicated trauma service. Of non-vascular specialists, 43% felt their training was adequate to manage vascular trauma and only one-third of general surgical consultants felt adequately prepared to manage acute cardiothoracic injuries. The median number of trauma laparotomies undertaken annually was 2 for blunt injury and 1 for penetrating injury. Of HSTs, 21% had not performed a splenectomy for trauma and 44% had no experience of packing for liver injuries. CONCLUSIONS: There is limited experience and training in the surgical management of torso trauma in the UK. Implementation of the recommendations from Better Care for the Severely Injured will be hampered unless steps are taken to maximise experience and improve training.

Abdominal Injuries↗
PubMed1999

Effect of lung volume reduction surgery on bony thorax configuration in severe COPD.

STUDY OBJECTIVES: Hyperinflation in patients with severe COPD is associated with an increased anteroposterior (AP) rib cage diameter. We sought to determine whether bilateral lung volume reduction surgery (LVRS) affects bony thorax configuration. DESIGN: Prospective of clinical data collection before and after LVRS. SETTING: Tertiary-care university medical center. PATIENTS: We measured multiple AP and transverse thoracic diameters, by using plain chest roentgenograms (CXRs) in 25 patients (11 men, 14 women), and thoracic CT scans in 14 patients (7 men, 7 women), preoperatively and 3 months postoperatively. A subgroup of 7 patients (reference data) also had CXR thoracic diameter measurements made, using films obtained previously within a year of their presurgical evaluation. Another subgroup of 10 patients had CT scan measurements also made 12 months postoperatively. MEASUREMENTS AND RESULTS: CXR dimensions were taken at the level of the manubrium sterni (M) and thoracic T7 and T11 levels. CT dimensions were taken at T4, T6, T8, and T10 levels. At each level, left (L), midsagittal (C), and right (R) AP and maximal transverse diameters were measured. The sum of the three AP diameters (Total) was used for calculations. Patients also underwent tests such as spirometry, lung volumes, diffusing capacity of the lung for carbon monoxide, 6-min walk distance (6MWD), and transdiaphragmatic pressures during maximum static inspiratory efforts (Pdimax sniff) measured before and 3 months after LVRS. Patients were (mean +/- SD) 58+/-8 years old, with severe COPD and hyperinflation (FEV1, 0.68+/-0.23 L; FVC, 2.56+/-7.3 L; and total lung capacity [TLC], 143+/-22% predicted). After LVRS, AP diameters were reduced at thoracic level T7 (from 24.2+/-2.0 cm to 23.3+/-2.2 cm, p = 0.0002), and transverse diameters were reduced at T7 (from 26.8+/-1.9 cm to 26.4+/-1.7 cm, p = 0.001) and T11 (from 29.9+/-2.2 cm to 29.5+/-2.2 cm, p = 0.03), as measured using the CXR. In contrast, thoracic diameters were similar in subjects with CXRs before LVRS and within 1 year before evaluation. CT-measured AP diameters were significantly reduced 3 months after LVRS at T6, (from 48.8+/-6.0 cm to 46.7+/-5.4 cm, p = 0.02), T8 (from 54.2+/-7.0 cm to 52.3+/-6.5 cm, p = 0.004), and T10 (from 53.8+/-7.5 cm to 51.2+/-8.0 cm, p = 0.001), but not at T4. These AP diameter reductions directly correlated with the postoperative reductions in TLC and residual volume, and also with the increases in Pdimax sniff and 6MWD after LVRS. The reduction in AP diameters at thoracic levels T8 and T10 seen 3 months after LVRS remained stable at 12-month follow-up, whereas those measured at T6 lost statistical significance. CT-measured transverse diameters were unchanged at all levels after LVRS. CONCLUSIONS: We conclude that LVRS decreases mid-to-lower AP rib cage diameter as assessed by CXR and thoracic CT. Although transverse diameters were reduced on CXR, the magnitude was small and was not confirmed with CT. After LVRS, AP diameter reductions are most likely the result of reduction in lung volume, and they are associated with improvements in diaphragm strength and exercise endurance.

Female↗
PubMed2005

Scanning beyond anatomic limits of the thorax in chest CT: findings, radiation dose, and automatic tube current modulation.

OBJECTIVE: Our objective was to determine additional radiation dose associated with scanning beyond the anatomic limits of the thorax in chest CT protocol and to assess the effect of z-axis modulation on the additional radiation dose associated with the scanning protocol. MATERIALS AND METHODS: "Extra" images for routine chest CT were defined as those above lung apices (supraapical) and those caudal to the lowermost portion of lung parenchyma (infrapulmonary), including images obtained beyond the adrenal glands (infraadrenal). One hundred and forty-eight consecutive chest CT examinations (70 men, 78 women; age range, 15-90 years) performed September 13-25, 2003, were reviewed to determine the number of supraapical, infrapulmonary, and infraadrenal extra images. All examinations were performed using z-axis modulation (n = 70) or fixed tube current (n = 78). The CT dose index volume and dose-length product (DLP) values for the extra images were calculated. Two radiologists reviewed these extra images for pathologic findings. Student's t test was used to perform the statistical analysis. RESULTS: One hundred forty-four (97%) examinations had supraapical extra images and 145 (98%) had infrapulmonary extra images. A total of 31 additional findings were observed in extra images. Most clinically important findings were identified in patients with a history of malignancy. With z-axis modulation, the mean DLP for supraapical and infrapulmonary extra images was 39.98 mGy x cm and 132.59 mGy x cm, respectively. With fixed tube current, the mean DLP for supraapical and infrapulmonary extra images was 30.31 mGy x cm and 95.91 mGy x cm, respectively. CONCLUSION: A substantial number of extra images are acquired during chest CT that do not add clinically important information in patients with nonmalignant indications. The use of z-axis modulation increased radiation dose for the extra images.

Adolescent↗
PubMed2000

Reduction of contrast material dose and artifacts by a saline flush using a double power injector in helical CT of the thorax.

OBJECTIVE: Our objective was to evaluate a combined method of contrast material bolus followed by saline solution flush for thoracic helical CT and statistical comparison with a uniphasic injection protocol. MATERIALS AND METHODS: Fifty patients underwent helical CT of the thorax using 60 ml of contrast material (370 mg I/ml) followed by flushing with 30 ml of physiologic saline solution. These 50 patients had been examined before using our previous protocol, 75 ml of the same contrast material without a subsequent saline solution. Mean attenuation values for both protocols were measured in the superior vena cava, the pulmonary trunk, and the ascending aorta. Image artifacts and mediastinal and hilar depiction were graded and compared. RESULTS: Mean attenuation values in the superior vena cava were considerably higher in the regimen without saline solution flush (459 H versus 352 H) and in the pulmonary trunk and the ascending aorta were almost identical for both protocols. Injection of saline solution diminished surrounding artifacts (p = 0.001). Grading results for the evaluation of mediastinal and hilar structures were not significantly different in the two protocols (p = 0.564). CONCLUSION: Injection of contrast material followed by a saline solution bolus using a double power injector when performing thoracic helical CT allows a 20% reduction of contrast material volume to 60 ml with a similar degree of enhancement. In addition, perivenous artifacts in the superior vena cava are significantly reduced.

Adult↗
PubMed1984

Improved lung-thorax compliance in the premature rabbit neonate after treatment with dibuturyladenosine-3':5'-cyclic monophosphate.

Premature rabbit neonates, delivered on day 28 of gestation, were treated with a single dose of dibuturyladenosine-3':5'-cyclic monophosphate (cyclic AMP), 300 mg/kg, immediately after delivery, saline-injected litter-mates serving as controls. All animals were kept in body plethysmographs and ventilated artificially with 100% oxygen for 1 h, with a maximal tidal volume of 10 ml/kg body weight. Lung-thorax compliance was significantly improved in animals treated with cyclic AMP, both 30 and 60 min after onset of ventilation (0.92 +/- 0.09 vs. 0.59 +/- 0.08 ml/cm H2O.kg and 0.96 +/- 0.09 vs. 0.53 +/- 0.08, p less than 0.005), but there was no improvement in alveolar air expansion, evaluated histologically. Phosphatidylglycerol was absent in alveolar wash from all control animals, but present in 3 of the 8 pooled samples from the animals treated with cyclic AMP; this difference was not statistically significant, however.

Animals↗
PubMed1998

Helical CT applications in the thorax and abdomen.

The past few years have witnessed a massive explosion in clinical applications for computed tomography (CT) as a result of exponential advances in technology. Most clinical practitioners have a limited understanding of the complexities and dynamics of modern CT, and even many radiologists are unable to keep up with the rapid evolution in refinements. In this article, Dr Rappaport summarizes some of the most recent advances in use of helical, or spiral, CT to diagnose diseases of the thorax and abdomen.

Angiography↗
PubMed1987

Trauma of the airway and thorax.

Children continue to sustain life-threatening injury that can be treated successfully. Management of the airway and breathing are the crucial steps which assure adequate ventilation of the child. If properly prepared, those individuals responsible for the emergency treatment of children should be able to save a high percentage of children who suffer injuries to the airway and thorax.

Airway Obstruction↗
PubMed1976

[Indications for the reconstruction of the unstable thorax due to serial rib fractures and respiratory insufficiency].

Because of the impending danger of bronchopneumonial infection caused by hospital germs we consider it of utmost importance in the care and treatment of patients with instable thorax to shorten the period of intubation and artificial respiration. By stabilizing 3 or 4 chozen ribs within the flailing chest wall, we found it possible to significantly reduce the period of intubation, intensive care and hospitalisation. The splinting of several ribs individually by introducing socalled "Rehbein plates" into the medullary cavity of those in question proved to be a trustworthy method in achieving this goal.

Cross Infection↗
PubMed1999

[Tracheobronchoscopy in injuries of the thorax and neck].

The results of examination and treatment of patients with penetrating wounds of the thorax and the neck are analysed. Diagnostic potential abilities of roentgenography and tracheobronchoscopy are evaluated comparatively. High diagnostic and curative effectiveness of tracheobronchoscopy is detected, which is indicated in diagnosis of the wounds of the larynx and the trachea as well as in cases of technical difficulties during endotracheal intubation. Besides, tracheobronchoscopy is indicated in postoperative period for sanation of the tracheobronchial tree under visual control for prevention of broncho-pulmonary complications.

Adolescent↗
PubMed1999

Open-thorax guinea pig model for defibrillation.

BACKGROUND AND PURPOSE: Guinea pigs are used as models for study of ventricular tachyarrhythmias (VT); however, the tachyarrhythmia often is transient and does not persist. We developed an open-thorax guinea pig model of sustained ventricular fibrillation (VF). METHODS: Bilateral thoracotomy was performed on eight guinea pigs weighing 865 to 1,464 g, and two sutures were positioned in the right ventricular apex for the purpose of pacing. Two methods were used to induce VF: a 50-Hz burst (normal pacing), and an initial 15 beats at 70% of the R-R interval followed by a 100-Hz burst for 84 beats (rapid pacing). Fifteen attempts at inducing VF were performed by use of each method. Blood pressure was recorded before and after development of VF, which was defined as VT with mean blood pressure consistently <10 mm Hg. A final observation was obtained using the normal pacing method without defibrillation. RESULTS: Use of both methods successfully induced VF. A significant relationship between body weight >1,021 g and ability to sustain and survive VF was detected. CONCLUSION: The guinea pig is a useful rodent model for the study of VF and defibrillation.

Animals↗