High-resolution computer tomography of diffuse infiltrative lung diseases

During a period of 17 months, a total of 101 patients were examined by high resolution computed tomography (HRCT) whose minor focal changes revealed by chest X-ray raised the suspicion of diffuse infiltrative pulmonary disease. The disease of the interstitium was primarily caused by idiopathic pulmonary fibrosis (19%), autoimmune disease (18%), Boeck sarcoidosis (18%) as well as by specific (16%) and aspecific inflammation (12%). HRCT disclosed reticular (61%), nodular (55%), ground-glass opacity-like (48%), emphysematous (33%) and ring-like changes (17%). Also transbronchial excision was performed in 51 patients the results of which were compared to the changes observed during HRCT. Concerning fibrosis and inflammation, HRCT and histological analysis showed identical results in 70%. According to the authors observations, this technique is suitable for detection of fairly fine fibrotic, empysematous and inflammatory signs and for defining the activity of the individual disease as also for the selection of the optimal site of transbronchial excision. HRCT is a useful investigative method both for diagnosing diffuse infiltrative pulmonary disease as well as in following up the effectiveness of treatment.     

The recording of parenchymal lung changes in smokers by high-resolution computed tomography

Using Caco-2BBe monolayers as a model of the intestinal epithelium, we tested the hypothesis that reactive oxygen metabolites contribute to lactic acid-induced hyperpermeability. Compared to monolayers incubated at normal pH (i.e., 7.4) monolayers incubated in medium titrated to extracellular pH (pHo) 5.0 with 10 mM lactic acid demonstrated increased permeability to both fluorescein sulfonic acid (FS) and fluorescein isothiocyanate-dextran (average molecular mass = 4000 Da; FD4). Lactic acid-induced hyperpermeability to both FS and FD4 was reduced by adding either 30 microM EUK-8, a superoxide dismutase/catalase mimetic, or catalase (10(4) U/mL). Incubation of monolayers with lactic acid increased cellular malondialdehyde content, a measure of lipid peroxidation. EUK-8 (30 microM) completely abrogated this effect. Incubation with ferrous sulfate (100 microM) exacerbated both lactic acid-induced hyperpermeability to FS and lactic acid-induced lipid peroxidation. Iron chelation with 1 mM diethylene triamine pentaacetic acid (DTPA)-trisodium calcium salt attenuated lactic acid-induced hyperpermeability, whereas iron-loaded DTPA (1 mM) was not protective. Treatment with DTPA-trisodium calcium salt also ameliorated lactic acid-induced lipid peroxidation. Incubation with lactic acid (pHo 5.0) for 16 h increased the cellular content of low molecular weight iron species. Incubation with lactic acid (pHo 5.0) for 24 h significantly increased the percentage of oxidized protein-bound thiols in Caco-2BBe cells. We conclude that lactic acidosis induces hyperpermeability in Caco-2BBe monolayers, in part, via an iron-dependent increase in reactive oxygen metabolite-mediated damage.     

Early diagnosis of lentivirus-induced infiltrative lung disease in sheep by high resolution computed tomography

The visna-maedi lentivirus can induce an interstitial pneumonitis in sheep, and provides a convenient example to study natural or experimental lentiviral pathology. We wanted to determine whether high resolution computed tomography (HRCT) is able to detect early morphological changes following lentiviral infection in the lungs. Spontaneously infected adult sheep (n=3) and experimentally infected lambs (n=5) were compared to uninfected controls (n=4). The HRCT scans generally showed abnormal features in infected animals, including: increased parenchymal density; alveolar oedema; thickened interlobular septa; and increased density in peribronchiolar areas. HRCT was more sensitive than chest radiography for the early diagnosis of interstitial pneumonitis, although one sheep with advanced disease and radiographic and histopathological abnormalities had a paradoxically normal scan. One control animal showed minor abnormalities on scanning, which were probably due to the procedure used for anaesthesia. The HRCT observations were confirmed by postmortem histological examination of the lungs. In conclusion, high resolution computed tomography provides a noninvasive means of following the development of lung pathology in a natural ovine model of lentiviral disease.     

Video thoracoscopic lung biopsy in diffuse interstitial lung diseases

The present study examined the use of video thoracoscopic lung biopsy (VTLB) in diffuse interstitial lung disease, in comparison with open lung biopsy (OLB). Twenty and fifteen patients underwent VTLB and OLB, respectively, from 1987 to 1997 at the Central Chest Hospital, Thailand. Data in mean (SD). The mean age was 39 years in both groups. VTLB yielded equivalent size of lung tissues, 4.7 (2.32) cm3, and was as diagnostically useful as OLB. Estimated blood loss, 60 (37) mls, and length of pleural drainage, 2.8 (0.5) days, were comparable in either technique. As OLB had been in practice for decades, it took shorter operative time, 64 (11) mins, than VTLB, 105 (30) mins, (p = 0.005). Both VTLB and OLB approaches were safe and not associated with major postoperative complications.     

Peripheral airways obstruction on high-resolution computed tomography in chronic severe asthma

BACKGROUND: An association between fats and colorectal carcinoma has been suggested, but the epidemiologic evidence by type of dietary fat is far less clear. Colorectal carcinoma rates have been relatively low in Mediterranean countries compared with most other Western countries, but the components of the Mediterranean diet responsible for this favorable pattern are unclear. METHODS: The relationship between various added (seasoning) fats and colorectal carcinoma risk was investigated using data from a case-control study conducted between January 1992 and June 1996 in six Italian areas. Cases were 1953 patients with incident, histologically confirmed colorectal carcinoma (1225 of the colon and 728 of the rectum) admitted to the major teaching and general hospitals in the study areas. Controls were 4154 subjects with no history of cancer who were admitted to hospitals in the same catchment areas for acute, nonneoplastic diseases unrelated to the the digestive tract and requiring no long term modifications of diet. Dietary habits were investigated using a validated food frequency questionnaire including 78 items. Lipid intake was estimated by taking into account the content of seasoning lipids in different dishes, the frequency of consumption and portion size of each dish, and individual fat intake patterns. RESULTS: The odds ratios (OR) for successive tertiles of olive oil intake, compared with the lowest one, were 0.87 (95% confidence interval [CI], 0.75-1.01) and 0.83 (95% CI, 0.70-0.99) (chi2trend = 4.49, P = 0.03) when colorectal carcinoma was analyzed as a whole, 0.82 (95% CI, 0.68-0.98) and 0.81 (95% CI, 0.66-0.99) (chi2trend = 4.05, P = 0.04) for colon carcinoma, and 0.96 (95% CI, 0.77-1.19) and 0.88 (95% CI, 0.66-1.12) for rectal carcinoma. For specific seed oils (including sunflower, maize, peanut, and soya), the OR for colorectal carcinoma was 0.91 in the highest tertile of intake, and the corresponding values were 1.01 for mixed seed oils and 0.93 for butter. None of these estimates was significantly different from the unity. Allowance for vegetable intake attenuated the apparent protection from olive oil consumption (OR, 0.94 for colon and 0.97 for rectum for the highest tertile), which still was apparent in younger subjects (OR, 0.82 for colon and 0.69 for rectum). CONCLUSIONS: In this study, seasoning fats did not appear to increase the risk of colorectal carcinoma, and there was little evidence for a differential effect by fat type. If such a differential effect exists, it is minor and could favor olive oil.     

The diagnostic and treatment characteristics of focal liver lesions using computed tomography

Under analysis is an experience with examining and treatment of 167 patients with focal lesions of the liver using computed tomography. Percutaneous transhepatic puncture and draining the hepatic abscesses and cysts under control of computed tomography is an independent method of treatment used in 53 patients. The technique of performing the puncture and drainage is described. Specific features of surgical treatment of focal lesions of the liver are described. Decompression of bile ducts in the postoperative period is shown to be necessary. A conclusion is made about high efficiency of computed tomography in diagnosis and treatment of focal lesions of the liver.     

On segmentation of lung parenchyma in quantitative computed tomography of the lung

Our purpose in this study was to investigate the influence of segmentation threshold and number of erosions on parameters used in quantitative computed tomography (CT) of the lung (erosions are shrink operations on the segmented area). Parameters assessed were mean lung density, area of the segmented lung, two percentiles, and the pixel index, which is the relative area of the histogram below -905 Hounsfield Units (HU). We analyzed images of ten emphysematous and ten nonemphysematous patients, that had been scanned at carina level in inspiration and expiration, using sections of 1, 2, 3, 5, and 10 mm in combination with a standard, a smooth, and an ultrasmooth reconstruction kernel. The lungs were segmented using pixel tracing at thresholds of -200, -400, and -600 HU with 0-4 erosions, followed by histogram analysis. The area of the segmented lungs decreased with 0.9%-3.2% per 100 HU decrease in threshold and with 2.2%-3.1% per erosion, dependent on patient group and respiratory status. Estimated mean lung density changed up to 30% by changing the threshold and the number of erosions. The pixel index and the 10th percentile depended only slightly on threshold and number of erosions, but the 90th percentile showed a strong dependence of up to 40%. It is concluded that the segmentation protocol can have a large impact on densitometric parameters and that standardization is mandatory for obtaining comparable results. Ideally a threshold equal to the average of the densities of lung and soft tissue should be used, but -400 HU will do in a limited but common density range (-910 to -790 HU). For densitometry two erosions are recommended, for volumetry zero erosions should be used.     

The assessment of the severity of pulmonary edema by computed tomography. A comparison between high-resolution computed tomography, objective evaluation with density masks and functional tests

The results of high-resolution computed tomography (HRCT) were correlated with those of pulmonary function tests, chest films and CT expiratory density mask values in the evaluation of pulmonary emphysema in 33 symptomatic subjects. Emphysema was quantitated with both subjective and objective measurements. Conventional chest films were useful to diagnose severe emphysema but its actual extent was more reliably evaluated with CT scoring systems. HRCT and density mask correlated well with function tests, but the former method exhibited stronger correlation with carbon monoxide diffusion capacity. The opposite was true for hyperinflation and expiratory obstruction variables. Subjective CT estimates, which are quick and easy to perform, were seen to correspond more specifically to the pathophysiologic derangement and should therefore be used to evaluate the anatomic extent of disease. The functional severity of emphysema correlated only with the overall extent of disease and not with its regional distribution in the upper or lower lungs. Finally, in 4 cases (12.1%) with low CT scores, FEV1 was reduced but diffusion capacity values were normal. In one of these patients HRCT showed signs of bronchiolitis. In fact, small airway disease might be a more critical factor in determining functional impairment than the actual anatomical emphysema.     

High-resolution computed tomography sampling for detection of asbestos-related lung disease

RATIONALE AND OBJECTIVES: We determined whether a limited number of high-resolution computed tomography (HRCT) scans will effectively screen for interstitial lung disease (ILD) in a population of individuals exposed to asbestos. METHODS: We retrospectively reviewed the computed tomography studies of 49 patients exposed to asbestos. HRCT in the supine and prone positions had been performed at specifically preselected levels. Two teams of thoracic radiologists evaluated, on separate occasions: (1) all images, (2) prone images only, and (3) a single prone image through the lung bases for the presence of diffuse ILD. RESULTS: A relatively high level of accuracy was obtained with a single prone scan. However, improvement to 95% or better was found when additional prone images were used. CONCLUSION: A screening study for ILD, in this case patients exposed to asbestos, may be performed by preselected prone HRCT images only. The ease and decreased time of performing the procedure make screening relatively large patient groups for ILD more feasible.     

Three-dimensional computed tomography in the head and neck diseases with bony abnormalities

The purpose of this study was to define the role of three-dimensional (3D) computed tomography (CT) in the head and neck diseases with bony abnormalities. Thirty-two patients were examined with a low dose radiation technique. Three-dimensional CT clearly delineated bony lesions in 27 of 32 patients. Three-dimensional CT could not demonstrate subtle bony erosions infiltrated by tumor, a temporal bone fracture, and a blow-out fracture, although two-dimensional (2D) images obtained before the 3D reconstructions clearly depicted those lesions. These two kinds of CT technique were thought to be complimentary.     

Imaging of hamate bone fractures in conventional X-rays and high-resolution computed tomography. An in vitro study

BACKGROUND: To explore the impact of a prevention program on the eating and body attitudes of a sample of adolescent schoolgirls. METHODS: The program involved lessons and group discussions of general adolescent problems and eating disorders. A total of 254 16-year-old schoolgirls were evaluated, of whom 154 participated in the program and a further 154 subjects formed the control group. Variations in weight, Eating Attitudes Test and Eating Disorders Inventory at a 1-year follow-up were compared for the two groups. RESULTS: Among high-risk subjects, no significant differences were found between the prevention and the control group. The preventive program appeared to reduce significantly body dissatisfaction and to decrease the risk of bulimic attitudes in low-risk subjects. CONCLUSIONS: Providing schoolgirls with the correct information about eating disorders did not encourage unhealthy attitudes to eating and weight regulation practices. However, for high-risk subjects more intensive and specific intervention may be required, for which further research is needed.     

Mechanical properties of ewe vertebral cancellous bone compared with histomorphometry and high-resolution computed tomography parameters

This paper is the result of discussions between scientists working in widely separated areas, united by an interest in the hippocampus. The discussions focused on the possible role of GABA in the development and maturation of the hippocampus and in neurodegeneration in Alzheimer's disease (AD). GABA neurons are among the first to differentiate in the hippocampus and the properties of GABA neurotransmission in the developing hippocampus are distinct from those in the adult. GABAergic transmission may play a role in the clustering and maturation of GABA receptors, as well as of receptors for other neurotransmitters. The development and maturation of synaptic connections involves changes in the organization of the cytoskeleton, and mechanical force generation is probably required to establish appropriate points of contact. This generation of force may require coupling of specific receptors to the cytoskeleton through specialized proteins. In AD, much of the developmental process is progressively unraveled in the hippocampus, as afferent fibers, most notably from entorhinal excitatory neurons and from basal forebrain cholinergic cells, degenerate. This denervation undoubtedly has consequences for receptor systems, dendritic morphology and the underlying cytoskeleton. GABA neurons remain in the AD hippocampus, and may actually contribute to abnormal firing and degeneration of remaining pyramidal neurons. This attempt to bring together data from different areas of research has allowed the development of a scheme which identifies significant specific gaps in our knowledge, which could be readily filled by focused experimental work.     

Diagnosis of infra-alveolar bony lesions in the dentate alveolar process with high-resolution computed tomography. Experimental results

RATIONALE AND OBJECTIVES: Conventional intraoral radiography was compared with axial computed tomography (CT) scans for identification and classification of bony pockets in dentate jaw segments. METHODS: Fifty-five artificial bone defects were produced in six dentate jaw segments. The jaws were examined radiographically using a dental x-ray unit and by contiguous axial CT scans. Identification, classification, and vertical depth of the bony defects were compared among the specimens, radiographs, and CT scans. RESULTS: On the intraoral radiographs, 38 (69%) bony lesions were identified, and the vertical depth was underestimated by a mean of 2.2 mm, compared with the objective measurements on the jaws. In contrast, all artificial bony lesions (100%) were identified and classified on the axial CT scans and the vertical depth was underestimated by a mean of 0.5 mm. CONCLUSIONS: High-resolution CT improves the identification and metric assessment of the vertical dimension of infra-alveolar bony lesions compared with conventional intraoral x-ray films and allows these defects to be classified according to the number of existing walls into one-walled, two-walled, and three-walled bony pockets. In patients with apically extended metallic restorations, the image quality could be limited by artifacts.     

Usefulness of computed tomography and scintigraphy in diagnosis of emphysematous bullae in the lung

The x-ray examinations usually do not reveal morbid changes after lung expansion in the treatment of spontaneous pneumothorax. In our observation computed tomography (CT) and scintigraphy enable not only the exact determination of the extent of changes but also they disclose bullae invisible in conventional chest radiographs. 15 patients with cured spontaneous pneumothorax and 10 patients with radiographic evidence of a bulla or bullae were examined. CT scans showed bullae from 3 to 18 cm in diameter involving predominantly the upper lobes. 4 patients had additionally subpleural or intraparenchymal bullae of various degrees. In all patients with cured spontaneous pneumothorax, CT scans revealed intraparenchymal bullae, and in 6 cases bilateral intraparenchymal bullae were revealed. Only in sites of large bullae, no isotopic marker or its low elimination was shown in perfusion and inhalation scintigraphy. 10 patients with giant bullous emphysema were operated; in 6 patients enucleation of bullae, in 3 lobectomy and in one patient bullectomy were performed. CONCLUSION: CT is a method of choice in the diagnosis of lung emphysematous bullae and it enables the detection of the changes undetectable in chest radiographs. Perfusion and inhalation scintigraphy is helpful in the diagnosis of large emphysematous bullae and postoperative follow-up examination.     

Cranial computed tomography interpretation in acute stroke: physician accuracy in determining eligibility for thrombolytic therapy

CONTEXT: Intracranial hemorrhage must be excluded prior to administration of thrombolytic agents in acute stroke. OBJECTIVE: To evaluate physician accuracy in cranial computed tomography scan interpretation for determining eligibility for thrombolytic therapy in acute stroke. DESIGN: Administration of randomly selected, randomly ordered series of 15 computed tomography scans from a pool of 54 scans that demonstrated intracerebral hemorrhage, acute infarction, intracerebral calcifications (impostor for hemorrhage), old cerebral infarction (impostor for acute infarction), and normal findings. PARTICIPANTS: A convenience sample of 38 emergency physicians, 29 neurologists, and 36 general radiologists. MAIN OUTCOME MEASURES: Physician determination of eligibility for thrombolytic therapy based on computed tomography scan interpretation. RESULTS: Average correct score by all physicians on all computed tomography scans was 77% (95% confidence interval, 74%-80%). Of 569 computed tomography readings by emergency physicians, 67% were correct; of 435 readings by neurologists, 83% were correct; and of 540 readings by radiologists, 83% were correct. Overall sensitivity for detecting hemorrhage was 82% (95% confidence interval, 78%-85%); 17% of emergency physicians, 40% of neurologists, and 52% of radiologists achieved 100% sensitivity for identification of hemorrhage. CONCLUSION: Physicians in this study did not uniformly achieve a level of sensitivity for identification of intracerebral hemorrhage sufficient to permit safe selection of candidates for thrombolytic therapy.     

Measurement of lung expansion with computed tomography and comparison with quantitative histology

The total and regional lung volumes were estimated from computed tomography (CT), and the pleural pressure gradient was determined by using the milliliters of gas per gram of tissue estimated from the X-ray attenuation values and the pressure-volume curve of the lung. The data show that CT accurately estimated the volume of the resected lobe but overestimated its weight by 24 +/- 19%. The volume of gas per gram of tissue was less in the gravity-dependent regions due to a pleural pressure gradient of 0.24 +/- 0.08 cmH2O/cm of descent in the thorax. The proportion of tissue to air obtained with CT was similar to that obtained by quantitative histology. We conclude that the CT scan can be used to estimate total and regional lung volumes and that measurements of the proportions of tissue and air within the thorax by CT can be used in conjunction with quantitative histology to evaluate lung structure.