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Magnetic resonance 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 effect of a study day on the subject of pain for nurses working at the thorax surgery department The aims of this investigation were: to describe patients' evaluation of pain and the treatment of pain after thorax surgery via sternotomy; to repeat the evaluation with another group of patients following a study day for nurses, featuring pain and pain treatment; and to examine whether the study day influenced the nurses in their treatment of pain. The investigation included daily evaluation of pain using a visual analogue scale (VAS), and an interview with the patients before discharge, where they were asked to review their experience of pain and its treatment. The nurses on the thorax surgery ward and on the intensive care unit (ICU) completed a questionnaire before and after the study day. Finally, a retrospective study of the case notes of the patients taking part was carried out. The results of the investigation showed a low assessment of pain by most patients during the daily evaluation. Asked to recall their pain when interviewed, the rating was higher. A small group of patients had more evident pain than others. When administering opiates the ICU nurses often chose a lower dose than the standing order prescribed. After the study day the nurses gave larger doses of intravenous opioids and the patients experienced less pain.
PURPOSE: To determine the minimum acceptable radiation dose for an adequate image quality in thorax a.p. radiographs of neonates using mobile X-ray equipment. MATERIAL AND METHODS: The influence of additional filtration (1.0 mm Al + 0.1 mm Cu) on image quality and radiation dose was determined for the speed class 400 screen-film system (SFS) and digital luminescence radiography (DLR) by making radiographs of a test phantom. Conventional and digital thorax a.p. radiographs of a rabbit were produced using various tube current-time products. The quality of the rabbit radiographs was judged by eight radiologists applying image quality criteria according to the German guidelines and the recommendations of the European Community. RESULTS: The added filter resulted in a dose reduction of 39% at 66 kV. DLR gave a further dose reduction of 25% in comparison to the speed class 400 SFS while maintaining adequate image quality, i.e. the radiographs were clinically acceptable with regard to quality criteria. CONCLUSION: The radiation dose resulting from thorax a.p. radiographs of neonates can be reduced by approximately 50% with the use of additional filtration and DLR.
The modelling of the human thorax and the impedance characteristics of the thorax are presented. A two-dimensional model of the thorax was constructed by using more than four hundred reference points. The input impedance was calculated by solving the Helmholtz equation for zero charge density and low frequencies. Variation in the impedance corresponds to the fluid in the lung and the degree of inflation, which is related to a given degree of pulmonary oedema.
An anatomic and imaging atlas was created to provide detailed information about the six pairs of thoracic nerves (phrenic nerves, vagus nerves, recurrent laryngeal nerves, sympathetic trunks, costal nerves, long thoracic nerves). Serial axial computed tomographic (CT) scans of the normal thorax were obtained and included in the atlas, along with drawings showing the proper location of each nerve relative to adjacent anatomic structures. CT scans obtained in both symptomatic and asymptomatic patients with various thoracic diseases were paired with appropriate drawings and normal CT scans in the atlas. This format was designed to help determine the presence and severity of related disease, including injury from surgery, trauma, or penetrating injury, metastatic disease involvement, and, rarely, primary tumor. Although the nerves of the thorax are rarely identified at cross-sectional imaging, their location can be inferred by localizing easily identified anatomic landmarks. Familiarity with the functional anatomy and clinical significance of the nerves of the thorax is important for the correct interpretation of thoracic images.
A number of concepts in the CT evaluation of the thorax have been reviewed. The concepts have been presented through anatomic images generated on a specific CT system, but any equivalent system could have produced similar images. The important conclusions derived as a result of this review are: 1. Slice thickness, volume averaging and volume sampling are interrelated. Slice thickness and the orientation and inherent subject contrast of the anatomy to be studied usually determine the quality of the image obtained. 2. Thin section imaging (i.e., 5 mm and especially 1.5 mm) can demonstrate thoracic anatomy rarely (if ever) observed on thicker images (i.e., 10 mm). Although impractical for general analysis, thin section imaging provides insight into the potential limitations of a standard approach to thoracic evaluation. 3. CT analysis of the normal anatomy of the pericardium is incomplete. Although pathology related to the pericardium has been presented in the literature, more work is required to define: 1, the relationship, on CT, of the pericardium to structures within its confines; 2, abnormalities within the mediastinum that may affect the pericardium, and 3, lesions in the lung that may invade the mediastinum and pericardium. 4. The excellent contrast sensitivity of CT (aided by iodine infusion or bolus injection techniques and dynamic scanning) does not suffice to resolve certain problems in thoracic analysis. Extrapleural signs, the concept of invasion versus abutment, and the discrimination of benign from malignant mediastinal nodes continue to present diagnostic dilemmas in CT analysis of the thorax. 5. Interesting cases provide models for demonstrating CT pitfalls, mimics, and rarities. CT can be a valuable tool in resolving diagnostic dilemmas in some cases but creates dilemmas in others. 6. CT reformation images of the thorax can be dynamically generated on the scanner console. This hands-on technique can be a valuable tool for teaching anatomy in resident training programs.
Demonstration of central bronchiectasis (CB) with normal peripheral bronchi is an essential requirement for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). Although the results of bronchography remain the gold standard for demonstration of central bronchiectasis they are not always diagnostic. Moreover, it is an unpleasant invasive procedure which may be difficult to perform in a patient of allergic bronchopulmonary aspergillosis with acute severe asthma. In an attempt to find a safe and effective alternative to demonstrate central bronchiectasis computed tomography (CT) of the thorax was evaluated against bronchography. Twenty one patients with allergic bronchopulmonary aspergillosis underwent computed tomography of the thorax followed by bronchography. Of the 378 bronchopulmonary segments available for analysis, 42 had to be excluded because of consolidation or non-filling of the contrast dye, leaving 336 segments for evaluation. CB was identified on CT in all 21 patients. Detailed analysis of the visualized segments revealed that computed tomography (using 8 mm contiguous scans) identified 146 of the 212 segments showing central bronchiectasis on bronchography (sensitivity 70%) and 114 of the 124, read as normal on bronchography (specificity 92%). Supplemental 4 mm scans, used in 8 out of 21 patients improved the overall sensitivity of computed tomography to 83%, whilst the specificity remained unchanged at 92%. Thus, computed tomography of the thorax, being more acceptable to the patient, has the potential of being the investigation of choice for the demonstration of central bronchiectasis in patients with allergic bronchopulmonary aspergillosis.
STUDY OBJECTIVE: To make a descriptive analysis of the frequency and the type of thorax and lung injuries among the casualties of the two devastating earthquakes that occurred in Turkey in 1999. DESIGN: Records of the hospitalized patients injured in the earthquakes were examined retrospectively. RESULTS: Among the total of 356 hospitalized patients, 21 (9.7%) in the Izmit earthquake and 6 (7.6%) in the Duzce earthquake had thorax and lung injuries. Pneumothorax and rib fractures were the two most frequent pathologies and accounted for 50% and 33.3% of the injuries, respectively. CONCLUSION: Approximately 10% of the casualties of a great earthquake may be expected to have thorax and lung injuries, and traumatic chest diseases should be considered in planning the medical response strategies.
With improvement in computed tomography (CT) technology, including faster scanning and images with better detail, the indications for CT of the thorax have expanded. In many instances, data collected on earlier-generation scanners no longer apply. This report is an update of CT scanning of the thorax and includes information on the role of CT in diagnosis when specific clinical syndromes and diseases are suspected. It also addresses controversial subjects, such as the role of CT scanning in the staging of bronchogenic carcinoma and the evaluation of the solitary pulmonary nodule, as well as suggesting guidelines for deciding when a CT scan of the thorax is indicated.
The influence of (1) calcium concentration, (2) exposure technique, (3) reconstruction algorithm, (4) nodule size, and (5) nodule location on the CT attenuation values (CT density) of pulmonary nodules was examined in a frozen human thorax. Nodules with calcium concentrations of 0-310 mg/ml and diameters of either 0.95 or 1.59 cm were inserted into a frozen, unembalmed human thorax. The nodules were placed either at the lung apex or 4 cm below the tracheal carina. Each nodule was scanned on a GE CT 9800 scanner; five different exposure techniques were used. The slice thickness was uniformly 1.5 mm. As expected, increasing the kilovoltage caused a significant decrease in CT nodule density in all nodules with calcium concentrations greater than 80 mg/ml. The inverse relationship between kilovoltage and nodule density was exaggerated with increasing calcium concentration. A high-resolution (bone) algorithm gave a significantly higher CT number than did a smoothed (standard) algorithm, regardless of nodule size and location, but this difference could be attributed almost entirely to the edge-enhancement effect of the bone algorithm. The CT density of the larger nodules was significantly higher than that of the smaller nodules at calcium concentrations greater than 65 mg/ml for both standard and bone algorithms. Densities were significantly higher in the mid lung than in the apex with a standard algorithm, but this was not the case with a bone algorithm. The GE CT 9800 scanner had a linear response between CT density and increasing calcium concentration within the confines of a human thorax. A high-resolution (bone) reconstruction algorithm has higher spatial resolution but does show an edge-enhancing effect not found with the smoothed algorithm. Two major variables in CT densitometry for pulmonary nodules are the kilo electron voltage of the X-ray beam and the reconstruction algorithm used; these two parameters should be standardized, with a high kilovoltage and high-resolution algorithm favored on the GE CT 9800 scanner.
The value of radiographic examination of the thorax, fluoroscopy and echocardiography in demonstration and localization of intracardiac calcifications were compared in an investigation of 40 patients with valvular heart disease prior to planned cardiac catheterization or operation. Radiographic examination of the thorax revealed only the most severe calcifications. By means of echocardiography it proved possible to undertake a simple semi-quantitative characterisation of the calcified tissue with acceptable intra- and inter-observer variation. Echocardiography and fluoroscopy were found to be of equal value in demonstration of the degree of calcification of the heart. Echocardiography was, however, superior to fluoroscopy in fine localization of the calcifications. The relative and additive values of the methods could be illustrated employing Bayes' theorem and could be represented graphically provided that the observations carried out with the three methods could be considered independent of one another. It is concluded that radiographic examinations of the thorax is unsuitable for screening for cardiac calcifications. Fluoroscopy can no longer be considered to be the method of choice in assessing lesions of this type but should be employed in cases where echocardiography does not provide sufficient information or is not available. The greatest certainty in demonstration of calcifications is obtained with combined employment of fluoroscopy and echocardiography.
Sporadic informations in the literature that by means of CT of the thorax by far smaller intrapulmonary foci can be recognized in comparison to the conventional x-ray examination are just to be confirmed. With the help of instances the indication for thorax CT in germinal testicular tumours is presented. The evidence and exclusion, respectively, of pulmonary metastases are of decisive importance actually for the therapy and prognosis in patients with germinal testicular tumours. In this respect our observations confirm the indications for a CT-examination of the thorax in these groups of patients.
Cardiovascular diseases hold a place of considerable importance in national health schemes and various screening methods have been devised to determine and to control such diseases. One of the methods is based on the use of thorax photofluorographs obtained from regular nation-wide X-ray examinations. The ischemic heart disease is a significant group among cardiovascular diseases and it appears that dorsoventral photofluorography is an insufficient means for its recognition. For 250 subjects examined by intracardial methods for suspected ischemic heart disease, a retrospective study of dorsoventral thorax photofluorographs was performed along the lines of the classification by Richter and Böck. The results show that in about 75 percent of the cases of ischemic heart disease associated with serious lesions of the coronary vessels, no signs of changes in the heart contour were seen in photofluorographs of the thorax. It is concluded that the evaluation of chestfilm is an inadequate approach as far as the ischemic heart disease group is concerned within photofluorographic screening programmes for cardiovascular diseases.
PURPOSE: The aim of the study was to reduce investigation time, radiation dose, and contrast material when performing spiral-CT of the thorax. METHODS: 50 patients with different clinical diagnoses underwent spiral-CT of the thorax with double table feed and 45 ml contrast material (lopentol) were injected. Density measurements were performed as follows: main pulmonary artery without contrast injection, carotid artery, subclavian artery, ascending and descending aorta, aortic arch, main pulmonary artery and thoracic aorta after contrast injection. RESULTS: In comparison to the density of the main pulmonary artery without contrast injection there was an increase of density of 134 HU. 45 ml of the contrast agent were sufficient in all cases for delineation of the mediastinal vessels. Investigation time was 16-18 s and all patients were able to hold their breath during this time, so no artifacts were seen. Radiation dose was cut in half. CONCLUSION: Spiral-CT with double table feed enables investigations of the thorax in less than 20s. 45 ml of a contrast agent are sufficient for performing this examination. There are no essential diagnostic deficits with this technique.
Thoracic trauma represents 12.8% of all trauma patients treated in author's evaluated the contribution of new diagnostic methods, in particular CT and sonography, to determinate the indication of conservative therapy or early surgical treatment. From 1992 in the framework of the grant project the early surgical treatment of instable thorax was performed in 29 patients with polytrauma or severe associated thoracoabdominal trauma. Authors determined indications for thorax stabilisation after serious consideration, and stated contemporary contraindications of this treatment. They evaluated the therapeutic contribution of these methods and prepared in cooperation with the company Medin Nové Mĕsto the set of osteosynthetic material with accessories for treatment of instable thorax.
Impalement is an uncommon injury with only occasional reports in the literature. There are even fewer reports of impalement injuries limited to the thorax. We report herein the case of a 24-year-old man who survived impalement injury of the left side of the thorax with a steel rod while working at a construction site. The great vessels of the thorax were spared but the second thoracic vertebra was fractured resulting in complete paralysis of the left lower limb. The precise nature and extent of the injury were determined pre-operatively by computed tomography and aortography. The important principles of surgical management contributing to the successful outcome are described, these being minimal manipulation of the impalement object before and during transport, careful pre-operative planning and a multidisciplinary approach.
Elimination of errors due to poor attenuation correction is an essential part of any quantitative single photon emission tomography (SPET) technique. Attenuation coefficients (mu Tc) for use in attenuation correction of SPET data were determined using technetium 99m and cobalt 57 flood sources and using topographical information obtained from computed tomography (CT) scans and magnetic resonance (MR) images. In patients with carcinoma of the bronchus, the mean attenuation coefficient for 99mTc was 0.096 cm-1 when determined across a transverse section of the thorax at the level of the tumour by means of a 57Co flood source (13 patients) and 0.093 and 0.074 cm-1 as determined from CT scans for points in the centre of the tumour and contralateral normal lung, respectively (21 patients). In 18 patients with breast tumours, the mean attenuation coefficient for 99mTc was 0.110 and 0.076 cm-1 when determined from MRI cross-sections for points in the centre of the tumour and normal contralateral lung, respectively. This indicates significant overcorrection for attenuation when the conventional value of 0.12 cm-1 is used. A value in the range 0.08-0.09 cm-1 would be more appropriate for SPET studies of the thorax. An alternative approach to quantitative region of interest (ROI) analysis is to perform attenuation correction appropriate to the centre of each ROI (using topographical information derived from CT or MRI) on non-attenuation-corrected reconstructions.
A direct image reconstruction method of electrical impedance tomography (EIT) is evaluated using three-dimensional (3-D) finite element models of cylindrical and torso-shaped volume conductors. The cylindrical model is used to examine the effect of electrode configurations and the sensitivity to off-plane objects and to noise in the measured data. It is also used to validate the modeling procedures by comparison with experimental data acquired from a similar cylindrical tank filled with saline. Simulation results show only minor differences in performance between the various electrode configurations. In the second part, a realistic human thorax model constructed from CT images is used to evaluate monitoring of pulmonary edema by EIT. The conductivity, volume, and vertical position of an abnormal region in the lungs are varied to simulate the progress of edema. Dynamic EIT images are reconstructed from data computed for the inhomogeneous thorax (heart and lungs) as the reference set and a realistic amount of noise is added to reproduce the conditions in which the technique would be used in practice. Simulation results show that a 10 ml edema region with a conductivity equal to that of blood can be detected at a 40 dB signal-to-noise ratio (SNR). Detection of a smaller volume, in the order of 2 ml, should be possible by improving either the instrumentation to achieve 60 dB SNR or the performance of reconstruction algorithms.