ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Effective utilization of spiral computed tomography (CT) technology in imaging of the thorax requires an understanding of technical parameters that affect image and scan quality. This article discusses how operator-controlled scan parameters can be optimized to achieve diagnostic and cost-effective examinations appropriate for daily clinical practice.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Volumetric computed tomography (VCT) represents an important improvement over conventional CT for assessing most airway abnormalities. Elimination of misregistration due to variations in respiration coupled with decreased motion artifacts and the ability to obtain routine overlapping sections allow a more confident estimation of the presence and extent of disease. Recently, attention has focused on newer reconstruction techniques including: multiplanar reconstructions (MPRs), including curved multiplanar reformations; multiplanar volume reconstructions (MPVRs) using ray projection techniques, such as maximum and minimum projection imaging; external rendering, or 3D-shaded surface displays; and, most recently, internal rendering or so-called “virtual bronchoscopy”. Given the often redundant nature of many of these methodologies determining indications for their use remains to be established, especially by comparison to axial imaging. The purpose of this article is to review these various reconstruction techniques and, based on current knowledge, place them in an appropriate clinical context.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The use of traditional pulmonary function tests (PFT) to assess airflow obstruction is limited by the fact that these measurements are global and can neither express the potential regional heterogeneity nor localize the distribution of airways involved. High-resolution computed tomography (HRCT) is an established technique for the detailed evaluation of the pulmonary parenchyma. The development of helical scanning techniques enables volume datasets to be acquired through regions of interest in a single breathhold. Acquired during different phases of suspended respiration or under different physiologic conditions, these image sets provide potential insights into the relationships between airway structure and function. Volumetric data in also amenable to advance image processing algorithms enabling more precise characterization of bronchial morphology. This review considers the challenge of assessing cardiopulmonary function due to the complexity of the heart and lungs. The considerable insights that have been gained about airway physiology in animal experimentation are discussed. Studies investigating the role of volume acquisition's Helical CT and Electron Beam CT techniques of evaluating functional small airways function in humans are reviewed in detail and potential methods for analysis of airflow obstruction and detection of airway reactivity are extensively considered.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We reviewed the chest radiographic and thin-section computed tomography (CT) findings in three adult patients with air-filled paratracheal cysts communicating with the tracheal lumen. The air collections were located on the right side in each case. On plain radiographs, they appeared round or oval and were 1–2 cm in diameter. On CT scans, they appeared irregular with a small communication between the tracheal lumen and the cyst. Thin-section and three-dimensional reconstructed CT were useful in detecting the communication between the trachea and paratracheal air cyst. In one case, the communication was recognized at surgical resection and in the other two cases, the orifice in the tracheal wall appeared as a tiny, well-circumscribed hole at fiberoptic bronchoscopy.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The demographics of tuberculosis (TB) and the therapy of malignancies have significantly changed since the last comprehensive review of TB in cancer patients. Fifty-six patients with both TB and malignancy were identified from January 1989 through December 1994 in a population of 61,931 newly registered cancer patients. The frequency of TB in cancer patients was 90 per 100,000. TB was more frequent in foreign-born patients (p< 0.001) and in racial and ethnic minorities (p< 0.001) than in non-Hispanic whites. TB developed during therapy in 48%. TB was discovered synchronously with the malignancy in 30% and in 21% occurred ≥18 months after therapy. Pulmonary TB occurred in 50 (89%) patients and extrapulmonary TB in nine (16%) (three had both). Chest radiographic findings did not suggest TB in 20%. TB was less frequent in lung cancer (p< 0.001), head and neck cancer (p= 0.002), and solid hematologic malignancies (p< 0.001) than it had been historically, but the frequency was unchanged in acute leukemia patients (p = 0.46). TB in cancer patients occurs at a nine times greater frequency than in the general population. It is now most frequent in leukemia patients.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The purpose of this study was to assess the accuracy of chest x-ray (CXR) interpretation in the diagnosis ofPneumocystis cariniipneumonia (PCP), bacterial pneumonia (BP), and pulmonary tuberculosis (TB) in human immunodeficiency virus (HIV)-positive patients and to identify the frequency with which these infections mimic one another radiographically. The admitting CXRs of 153 HIV-positive patients with laboratory proven BP (n= 71), PCP (n= 73), and TB (n= 9) and those of 10 HIV-positive patients with no active disease were reviewed retrospectively and independently by three radiologists who were blinded to clinical and laboratory data. Median percent accuracies were as follows: TB, 84%; PCP, 75%; BP, 64%; and no active disease, 100%. Fifteen of 153 cases (9.8%) were shown to mimic other infections radiographically. A confident and accurate diagnosis can be made radiographically in the majority of cases of PCP, BP, and TB in HIV-positive patients at the time of hospitalization. In approximately 10% of cases, these infections may mimic one another radiographically.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The purpose of this controlled study was to determine the diagnostic accuracy of computed tomography (CT) in the diagnosis of round atelectasis (RA). We reviewed two groups of chest CT scans of 22 patients (with 24 masses). Group 1 scans represent 10 patients (12 masses) known to have RA, and Group 2 scans represent 12 patients with “RA look-alike” masses. Scans in both groups were selected for review by two of the authors and later independently reviewed by the other authors, who were blind to the actual diagnosis. Scans were rated for the presence/absence of 18 features ascribed to RA in the literature and assigned a percent probability of RA by each rater. Consensus was achieved for discordant ratings, and the individual percent probabilities were averaged to create a consensus probability. ROC curve analysis of the consensus percent probability showed that diagnostic accuracy significantly exceeded chance [area under curve (AUC) = 0.95,p< 0.001]. Of all the features of RA examined, the presence of converging bronchovascular markings discriminated best between RA and “RA look-alikes” (sensitivity 83%, specificity 92%, likelihood ratio 11). Presence of adjacent pleural thickening and pleural-based location were even more sensitive features of RA (100% each), but lacked specificity (33 and 67%, respectively; likelihood ratios 3 and 1.5, respectively). We conclude that (a) although the diagnostic accuracy of CT for RA was high in this series, radiographic diagnosis is imperfect and that (b) the presence of converging bronchovascular markings was the best discriminator between the two groups, but that no single CT feature permitted perfect discrimination.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Pulmonary arteries of the right middle (RML) and right lower (RLL) lobes lie toward the lung periphery relative to their corresponding bronchi, i.e., along their lateral or posterior aspects. In contrast, those of the right upper lobe (RUL) tend to be located along the medial or anterior aspect of the bronchi. We postulate that a reversal of the normal bronchoarterial relationship at the lung base may indicate combined RML and RLL collapse. We evaluated bronchoarterial relation by computed tomography (CT) and posteroanterior (PA) chest radiographs in patients with combined RML and RLL collapse. On PA chest radiographs, an inverse bronchoarterial relationship could be recognized in the lower perihilar region in seven of 10 patients. In the 10 patients with complete collapse of both the RML and RLL, CT disclosed that the normal bronchoarterial relationship of the RUL was preserved, despite caudal extension of the RUL. In no case were arteries visible along the lateral aspect of bronchi. Thus, on frontal radiographs, when the bronchoarterial relationship in the right lower lung is inverse to that of normal subjects, combined collapse is strongly suggested.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The aim of this study was to determine the frequency of radiographically evident central venous catheter misplacement in the azygos arch and to analyze whether the frequency of azygos arch cannulation is dependent on the anatomical site of catheter insertion. We reviewed 1,287 postprocedural examinations and 3,441 follow-up examinations. Catheters had been inserted through the left (6%) or right (15%) internal jugular veins and through the left (32%) or right (46%) subclavian veins. Radiographs were analyzed for possible catheter malposition in the azygos arch and for complications related to this malposition. Catheter malposition in the azygos arch was seen on 16/1,287 (1.2%) postprocedural radiographic examinations. Of the 16 malpositioned catheters, 11 (69%) had been inserted in the left subclavian vein, three (19%) in the left jugular vein, two (12%) in the right subclavian vein, and none (0%) in the right jugular vein. There was a statistically significant difference in the frequency of azygos arch cannulation between left- and right-sided catheters (p= 0.001). All complications consisted of venous perforations and were seen in three of 16 cases (19%). Azygos arch cannulation is a rare but hazardous central venous catheter malposition that occurs early after catheter insertion and carries a substantial risk for complication. The risk for azygos arch cannulation is substantially increased if catheters are inserted in left-sided veins. Because of the severity of subsequent complications, radiologists should be vigilant in the detection of this rare malposition.

ISSN:0883-5993    

出版商:OVID    

年代:1997

数据来源: OVID