Early lung cancer action project: a summary of the findings on baseline screening

PURPOSE

The Early Lung Cancer Action Project (ELCAP) is designed to evaluate baseline and annual repeat screening by low radiation dose computed tomography (low-dose CT) in persons at high-risk for lung cancer.

METHODS

Since starting in 1993, the ELCAP has enrolled 1,000 asymptomatic persons, 60 years of age or older, with at least 10 pack-years (1 pack per day for 10 years, or 2 packs per day for 5 years) of cigarette smoking, no prior cancer, and medically fit to undergo thoracic surgery. After a structured interview and informed consent, baseline chest radiographs and low-dose CT were obtained on each subject. The diagnostic work-up of screen-detected noncalcified pulmonary nodules (NCN) was guided by ELCAP recommendations which included short-term high-resolution CT follow-up for the smallest nodules. Baseline

RESULTS

On low-dose CT at baseline compared to chest radiography, NCN were detected three times as commonly (23% versus 7%), malignancies four times as commonly (2.7% versus 0.7%), and stage I malignancies six times as commonly (2.3% versus 0.4%). Of the 27 CT-detected cancers, 96% (26/27) were resectable; 85% (23/27) were stage I, and 83% (19 of the 23 stage I) were not seen on chest radiography. Following the ELCAP recommendations, biopsies were performed on 28 of the 233 subjects with NCN; 27 had a malignant and one a benign NCN. Another three individuals underwent biopsy outside of the ELCAP recommendations; all had benign NCNS: No one had thoracotomy for a benign nodule.

CONCLUSION

Baseline CT screening for lung cancer provides for detecting the disease at earlier and presumably more commonly curable stages in a cost-effective manner.

Early lung cancer action project: initial findings on repeat screenings

BACKGROUND

The Early Lung Cancer Action Project (ELCAP) was designed to evaluate the usefulness of annual computed tomography (CT) screening for lung carcinoma. With the baseline results having been reported previously, the focus of the current study was on the early results of the repeat screenings.

METHODS

A cohort of 1000 high-risk individuals was recruited for baseline and annual repeat CT screening. At last follow-up, a total of 1184 annual repeat screenings had been performed. A positive result from the screening test was defined as newly detected, one to six noncalcified pulmonary nodules with interim growth. The diagnostic workup of the individuals was guided by recommendations supplied by the ELCAP investigators to the collaborating clinicians.

RESULTS

Of the 1184 repeat CT screenings, the test result was positive in 30 (2.5%). In 2 of these 30 cases, the individual died (of an unrelated cause) before diagnostic workup and the nodule(s) resolved in another 12 individuals. In the remaining 16 individuals, the absence of further growth was documented by repeat CT in 8 individuals and further growth was documented in the remaining 8 individuals. All eight individuals with further nodular growth underwent biopsy and malignancy was diagnosed in seven. Six of these seven malignancies were nonsmall cell carcinomas (five of which were Stage IA and one of which was Stage IIIA) and the one small cell carcinoma was found to be of limited stage. The median size dimension of these malignancies was 8 mm. In another two subjects, symptoms prompted the interim diagnosis of lung carcinoma. Neither of these malignancies was nodule-associated but rather were endobronchial; one was a Stage IIB nonsmall cell carcinoma and the other was a small cell carcinoma of limited stage.

CONCLUSIONS

False-positive screening test results are uncommon and usually manageable without biopsy; compared with no screening, such screenings permit diagnosis at substantially earlier and thus more curable stages. Annual repetition of CT screening is sufficient to minimize symptom-prompted interim diagnoses of nodule-associated malignancies.

Early lung cancer action project: initial findings on repeat screenings

BACKGROUND

The Early Lung Cancer Action Project (ELCAP) was designed to evaluate the usefulness of annual computed tomography (CT) screening for lung carcinoma. With the baseline results having been reported previously, the focus of the current study was on the early results of the repeat screenings.

METHODS

A cohort of 1000 high-risk individuals was recruited for baseline and annual repeat CT screening. At last follow-up, a total of 1184 annual repeat screenings had been performed. A positive result from the screening test was defined as newly detected, one to six noncalcified pulmonary nodules with interim growth. The diagnostic workup of the individuals was guided by recommendations supplied by the ELCAP investigators to the collaborating clinicians.

RESULTS

Of the 1184 repeat CT screenings, the test result was positive in 30 (2.5%). In 2 of these 30 cases, the individual died (of an unrelated cause) before diagnostic workup and the nodule(s) resolved in another 12 individuals. In the remaining 16 individuals, the absence of further growth was documented by repeat CT in 8 individuals and further growth was documented in the remaining 8 individuals. All eight individuals with further nodular growth underwent biopsy and malignancy was diagnosed in seven. Six of these seven malignancies were nonsmall cell carcinomas (five of which were Stage IA and one of which was Stage IIIA) and the one small cell carcinoma was found to be of limited stage. The median size dimension of these malignancies was 8 mm. In another two subjects, symptoms prompted the interim diagnosis of lung carcinoma. Neither of these malignancies was nodule-associated but rather were endobronchial; one was a Stage IIB nonsmall cell carcinoma and the other was a small cell carcinoma of limited stage.

CONCLUSIONS

False-positive screening test results are uncommon and usually manageable without biopsy; compared with no screening, such screenings permit diagnosis at substantially earlier and thus more curable stages. Annual repetition of CT screening is sufficient to minimize symptom-prompted interim diagnoses of nodule-associated malignancies.

A consensus statement of the Society of Thoracic Radiology: screening for lung cancer with helical computed tomography

This consensus statement by the Society of Thoracic Radiology is a summary of the current understanding of low dose computed tomography (CT) for screening for lung cancer. Lung cancer is the most common fatal malignancy in the industrialized world. Unlike the next three most common cancers, screening for lung cancer is not currently recommended by cancer organizations. Improvements in CT technology make lung screening feasible. Early prevalence data indicate that about two-thirds of lung cancers that are detected by CT screening are at an early stage. Other data support the postulate that patients with lung cancers detected at this early stage have better rates of survival. Whether this will translate into an improved disease specific mortality is yet to be demonstrated. The suggested technical protocols, selection criteria, and method of handling the numerous benign nodules that are detected are discussed. It is the consensus of this committee that mass screening for lung cancer with CT is not currently advocated. Suitable subjects who wish to participate should be encouraged to do so in controlled trials, so that the value of CT screening can be ascertained as soon as possible.

Hut lung. A domestically acquired particulate lung disease

We report an illustrative case of advanced "hut lung," or domestically acquired particulate lung disease (DAPLD), in a recently emigrated nonsmoking Bangladeshi woman with a history of 171 hour-years of exposure to biomass smoke. She presented with symptoms of chronic cough, dyspnea, and early parenchymal lung disease. High-resolution computed tomography (CT) of the chest demonstrated numerous 2- to 3-mm nodules, sparing the pleural surface. To our knowledge, this is the first such report of CT findings in the literature. Bronchoscopy yielded typical anthracotic plaques and diffuse anthracosis with interstitial inflammation on histopathologic examination of biopsy specimens. DAPLD is potentially the largest environmentally attributable disorder in the world, with an estimated 3 billion people at risk. Caused by the inhalation of particles liberated from the combustion of biomass fuel, DAPLD results in significant morbidity from infancy to adulthood. Clinically, DAPLD manifests a broad range of disorders from chronic bronchitis and dyspnea to advanced interstitial lung disease and malignancy. While a detailed environmental history is essential for making the diagnosis in most individuals, for patients with advanced DAPLD, invasive modalities such as bronchoscopy with transbronchial biopsy and examination of bronchoalveolar lavage fluid help differentiate it from other diseases. Recognition of this syndrome and removal of the patient from the environment is the only treatment. The development of well-controlled interventional trials and the commitment of sufficient resources to educate local populaces and develop alternative fuel sources, stove designs, and ventilation are essential toward reducing the magnitude of DAPLD.

Lung nodule enhancement at CT: multicenter study

PURPOSE

To test the hypothesis that absence of statistically significant lung nodule enhancement (< or =15 HU) at computed tomography (CT) is strongly predictive of benignity.

MATERIALS AND METHODS

Five hundred fifty lung nodules were studied. Of these, 356 met all entrance criteria and had a diagnosis. On nonenhanced, thin-section CT scans, the nodules were solid, 5-40 mm in diameter, relatively spherical, homogeneous, and without calcification or fat. All patients were examined with 3-mm-collimation CT before and after intravenous injection of contrast material. CT scans through the nodule were obtained at 1, 2, 3, and 4 minutes after the onset of injection. Peak net nodule enhancement and time-attenuation curves were analyzed. Seven centers participated.

RESULTS

The prevalence of malignancy was 48% (171 of 356 nodules). Malignant neoplasms enhanced (median, 38.1 HU; range, 14.0-165.3 HU) significantly more than granulomas and benign neoplasms (median, 10.0 HU; range, -20.0 to 96.0 HU; P < .001). With 15 HU as the threshold, the sensitivity was 98% (167 of 171 malignant nodules), the specificity was 58% (107 of 185 benign nodules), and the accuracy was 77% (274 of 356 nodules).

CONCLUSION

Absence of significant lung nodule enhancement (< or = 15 HU) at CT is strongly predictive of benignity.

Early Lung Cancer Action Project: overall design and findings from baseline screening

BACKGROUND

The Early Lung Cancer Action Project (ELCAP) is designed to evaluate baseline and annual repeat screening by low-radiation-dose computed tomography (low-dose CT) in people at high risk of lung cancer. We report the baseline experience.

METHODS

ELCAP has enrolled 1000 symptom-free volunteers, aged 60 years or older, with at least 10 pack-years of cigarette smoking and no previous cancer, who were medically fit to undergo thoracic surgery. After a structured interview and informed consent, chest radiographs and low-dose CT were done for each participant. The diagnostic investigation of screen-detected non-calcified pulmonary nodules was guided by ELCAP recommendations, which included short-term high-resolution CT follow-up for the smallest non-calcified nodules.

FINDINGS

Non-calcified nodules were detected in 233 (23% [95% CI 21-26]) participants by low-dose CT at baseline, compared with 68 (7% [5-9]) by chest radiography. Malignant disease was detected in 27 (2.7% [1.8-3.8]) by CT and seven (0.7% [0.3-1.3]) by chest radiography, and stage I malignant disease in 23 (2.3% [1.5-3.3]) and four (0.4% [0.1-0.9]), respectively. Of the 27 CT-detected cancers, 26 were resectable. Biopsies were done on 28 of the 233 participants with non-calcified nodules; 27 had malignant non-calcified nodules and one had a benign nodule. Another three individuals underwent biopsy against the ELCAP recommendations; all had benign non-calcified nodules. No participant had thoracotomy for a benign nodule.

INTERPRETATION

Low-dose CT can greatly improve the likelihood of detection of small non-calcified nodules, and thus of lung cancer at an earlier and potentially more curable stage. Although false-positive CT results are common, they can be managed with little use of invasive diagnostic procedures.

Multinodular disease: anatomic localization at thin-section CT--multireader evaluation of a simple algorithm

PURPOSE

To evaluate the interobserver variability and accuracy of an algorithm for anatomic localization of small nodules evident on thin-section computed tomographic (CT) images of the lungs.

MATERIALS AND METHODS

Four experienced chest radiologists independently evaluated thin-section CT images in 58 patients by using an algorithm and a standard score sheet. Nodules were placed into four possible anatomic locations or categories: perilymphatic, random, associated with small airways disease, or centrilobular. Algorithm accuracy was assessed by comparing the localization by the observers to that expected for each specific disease in the study group on the basis of reports in the literature. Interobserver variability was assessed by placing cases into one of three groups: (a) complete concordance, (b) triple concordance, and (c) discordant.

RESULTS

All observers agreed in 79% (46 of 58) of the cases with regard to nodule localization; three of the four concurred in an additional 17% (10 of 58). The observers were correct in 218 (94%) of 232 localizations in the 58 cases. There were no apparent differences in the number of either discordant or incorrect localizations between the observers. The most noteworthy source of error and of disagreement between observers was the confusion of perilymphatic and small airways disease-associated nodules in a small number of cases.

CONCLUSION

The proposed algorithm is reproducible and accurate in the majority of cases and facilitates nodule localization at thin-section CT.

Non-small cell lung carcinoma: usefulness of unenhanced helical CT of the adrenal glands in an unmonitored environment

PURPOSE

To evaluate routine non-contrast material-enhanced helical computed tomography (CT) of the adrenal glands in patients with non-small cell lung carcinoma to facilitate characterization of adrenal masses detected in an unmonitored environment (i.e., the radiologist on duty did not look at the acquired images before the patient left the scanner).

MATERIALS AND METHODS

One hundred consecutive patients with non-small cell lung carcinoma were referred for CT evaluation of the chest; chest and abdomen; or chest, abdomen, and brain. All underwent unenhanced CT of the adrenal glands before the requested CT examination. The morphologic features, size, and attenuation values of the adrenal masses were calculated. Attenuation values of adrenal masses from prior imaging, if available, were compared with those at follow-up imaging to classify these masses. Variable unit cost increase in obtaining these additional images was estimated.

RESULTS

Fifteen adrenal masses were identified in 13 patients. In one patient, bilateral ill-defined adrenal masses were present. In 12 patients, 13 masses were sharply circumscribed: Seven were less than 10 HU and six were 20 HU or greater at unenhanced CT. Nine of these 12 patients received iodinated contrast material. Without the unenhanced CT, 10 adrenal masses in these nine patients would have been indeterminate for malignancy. In six of these nine patients, the adrenal mass was the only potential site of metastatic disease. The unenhanced CT data helped classify three of these masses as benign-10 HU or less- and three as indeterminate-greater than 10 HU.

CONCLUSION

Unenhanced CT of the adrenal glands can prospectively characterize adrenal masses and obviate further examination in patients with lung carcinoma.

Pulmonary nodule detection: low-dose versus conventional CT

PURPOSE

To quantitate the effectiveness of low-dose computed tomography (CT) in the identification of pulmonary nodules while controlling for anatomic nodule characteristics and to establish what factors lead to reduced diagnostic sensitivity at low-dose CT.

MATERIALS AND METHODS

Each of six participating radiologist independently rated 200 image panels by using a four-point confidence scale. Conventional images were obtained at 200 mAs; low-dose images were obtained at 20 mAs. To fully control their characteristics, nodules were simulated with a given diameter, shape, and section thickness while preserving the resolution, noise level, and reconstruction artifacts of the original images. Panels were matched so that nodules on low-dose and conventional images had equivalent sizes, locations, and relationships to blood vessels.

RESULTS

Among 864 positive panels, 259 (60%) of 432 low-dose panels and 272 (63%) of 432 conventional panels were correctly interpreted (P = .259). Lowering the x-ray dose significantly reduced the detectability of peripheral nodules (P = .019) and nodules separated from blood vessels (P = .044). Surprisingly, 3-mm nodules were detected with approximately equal sensitivity (P = .181) at conventional and low-dose CT. The specificity of low-dose images was 88% (148 of 168 panels) versus 91% (153 of 168 panels) for conventional images (P = .372).

CONCLUSION

Low-dose CT is acceptable for pulmonary nodule identification, making it suitable for primary screening. These results confirm the strong effect of size, location, and angiocentricity on the sensitivity of nodule detection with conventional CT.

Transbronchial needle aspiration (TBNA) in patients infected with HIV

Transbronchial needle aspiration (TBNA) of intrathoracic lymph nodes has been shown to be useful in the diagnosis and staging of bronchogenic carcinoma. With the exception of sarcoidosis, the usefulness of TBNA has not been widely investigated in other clinical settings. We investigated the utility of TBNA with a 19-gauge histology needle in HIV-infected patients with mediastinal and hilar adenopathy at Bellevue Hospital Center. We performed 44 procedures in 41 patients. Adequate lymph node sampling was obtained in 35 of 44 (80%), and diagnostic material was obtained in 23 of 44 (52%) procedures. TBNA was the exclusive means of diagnosis in 13 of 41 (32%) patients. Of the 44 procedures, 23 (52%) were performed in patients with mycobacterial disease, with TBNA providing the diagnosis in 20 of 23 (87%). In these patients, positive TBNA specimens included smears of aspirated materials for acid-fast bacilli in 11, mycobacterial culture in 14, and histology in 15. In other diseases, TBNA diagnosed sarcoidosis with noncaseating granulomata in 2 of 4 patients and non-small cell lung cancer in 1 of 2 patients. TBNA was not helpful in other diseases including Pneumocystis carinii pneumonia, infection with Cryptococcus or Nocardia, bacterial pneumonia, viral pneumonia, and Kaposi's sarcoma. No pulmonary diagnosis was established in five patients. No complications of TBNA occurred. We conclude that TBNA through the flexible bronchoscope is safe and effective in the diagnosis of intrathoracic adenopathy in HIV-infected patients, and is particularly efficacious in the diagnosis of mycobacterial disease. Furthermore, TBNA may provide the only diagnostic specimen in almost one-third of HIV-infected patients, thereby sparing these patients more invasive procedures such as mediastinoscopy.

Pulmonary aspergilloma and AIDS. A comparison of HIV-infected and HIV-negative individuals

OBJECTIVE AND METHODS

While pulmonary aspergilloma has been well described in immunocompetent hosts, to date and to our knowledge, there has not been a description of pulmonary aspergilloma in the HIV-infected individual. A retrospective review of cases seen by the Bellevue Hospital Chest Service from January 1992 through June 1995 identified 25 patients with aspergilloma. To investigate the impact of HIV status on pulmonary aspergilloma, we compared clinical presentation, progression of disease, treatment, and outcome in the HIV-infected patient vs the HIV-negative patient with aspergilloma.

RESULTS

Of the 25 patients identified, 10 were HIV-infected and 15 were HIV-negative. Predisposing diseases included tuberculosis (18/25, 72%), sarcoidosis (4/25, 16%), and Pneumocystis carinii pneumonia (3/25, 12%). All 25 patients had evidence of aspergilloma on chest CT. In addition, 17 of 25 patients had evidence of Aspergillus species in fungal culture, pathologic specimens, or immunoprecipitins. Hemoptysis was present in 15 of 25 (60%) (11/15 [73%] of the HIV-negative group vs 4/10 [40%] of the HIV-infected group). Severe hemoptysis (> 150 mL/d) occurred in 5 of 15 (33%) of the HIV-negative group vs 1 of 10 (10%) of the HIV-infected group. Disease progression occurred more frequently among the HIV-infected group (4/8, 50% vs 1/13, 8% in HIV-negative individuals). All patients with disease progression had lymphocyte subset CD4+ < 100 cells per microliter. Four of eight (50%) of the HIV-infected group vs 1 of 13 (8%) of the HIV-negative group died.

SUMMARY AND CONCLUSIONS

We conclude the following: (1) although tuberculosis and sarcoidosis are the most prevalent predisposing diseases, P carinii pneumonia in the HIV-infected individual is a risk factor for pulmonary aspergilloma; (2) HIV-infected individuals with CD4+ < 100 cells per microliter are more likely to have disease progression despite treatment; and (3) HIV-negative patients are more likely to have hemoptysis requiring intervention.

Volumetric (helical/spiral) CT (VCT) of the airways

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 artifact 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.

AIDS-related airway disease

To our knowledge, the importance of airway disease in HIV-positive patients has been infrequently noted. This deficit likely reflects a combination of factors including lack of familiarity with recent changes in clinical and epidemiologic patterns of pulmonary manifestations of HIV infection and documented limitations of chest radiography for identifying and differentiating airway disease from other causes of pulmonary disease in HIV-positive patients. Familiarity with the imaging findings for these various entities should facilitate prompt diagnosis and treatment. The accuracy of CT in detecting airway disease [55-59] is well established and should be of value in excluding more common diseases that may be initially confused with airway abnormalities [60, 61]. Small airways disease, in particular, which may be occult or mimic an interstitial infiltrate on chest radiography, can be recognized with CT as likely representing infectious bronchitis or bronchiolitis. Patients with findings suggesting bacterial infections may benefit from empiric antibiotic therapy. CT also may be valuable for differentiating between various noninfectious pulmonary diseases, allowing a presumptive diagnosis of parenchymal Kaposi's sarcoma in the appropriate clinical context. In distinction, by detecting localized endobronchial or parenchymal abnormalities in patients with mycobacterial or fungal infections or lymphoma, CT may be valuable for deciding between various invasive methods of obtaining either histologic or bacteriologic diagnoses.

Review: pneumothorax in patients with AIDS-related Pneumocystis carinii pneumonia

A retrospective review was performed to describe the clinical characteristics, course, and outcome of pneumothorax for all patients admitted to Bellevue Hospital, New York, with AIDS who had Pneumocystis carinii pneumonia (PCP) diagnosed between January 1985, through July 1991. Of 1360 patients with AIDS and PCP, 67 patients (4.9%) were identified with pneumothorax; a group of 50 is the subject of this review. Of these 50 patients, 22 patients (44%) developed spontaneous pneumothorax, 15 patients (30%) developed pneumothorax during mechanical ventilation, and 13 patients (26%) had pneumothorax after an invasive procedure. Of the 22 patients with spontaneous pneumothorax, 8 had cystic parenchymal abnormalities on the chest radiograph and 6 had a history of PCP. The majority of patients were treated with tube thoracostomy and/or surgical intervention. All 15 patients who developed pneumothorax during mechanical ventilation died. Results of pathologic studies revealed varying degrees of interstitial inflammation and fibrosis interspersed with areas of hemorrhage and necrosis, and presence of P carinii cysts. Autopsy specimens obtained in two cases demonstrated multiple parenchymal cavities and evidence of an alveolar eosinophilic exudate with P carinii organisms. Spontaneous pneumothorax in patients with AIDS usually occurs in association with PCP and is associated with significant morbidity. Patients at risk include those with cystic lesions on chest radiograph and those patients with a history of PCP. Patients with AIDS and PCP who develop pneumothorax during mechanical ventilation have a poor outcome.

Diffuse lung disease: assessment with helical CT--preliminary observations of the role of maximum and minimum intensity projection images

PURPOSE

To evaluate assessment of diffuse lung disease with helical computed tomography (CT) and maximum intensity projection (MIP) and minimum intensity projection images.

MATERIALS AND METHODS

Six patients with suspected lung disease (the control group) and 20 patients with documented disease underwent axial helical CT through the upper and lower lung fields. Findings on the MIP and minimum intensity projection images of each helical data set were compared with findings on the thin-section scan obtained at the midplane of the series.

RESULTS

Owing to markedly improved visualization of peripheral pulmonary vessels (n = 26) and improved spatial orientation, MIP images were superior to helical scans to help identify pulmonary nodules and characterize them as peribronchovascular (n = 2) or centrilobular (n = 7). Minimum intensity projection images were more accurate than thin-section scans to help identify lumina of central airways (n = 23) and define abnormal low (n = 15) and high (ground-glass) (n = 8) lung attenuation. Conventional thin-section scans depicted fine linear structures more clearly than either MIP or minimum intensity projection images, including the walls of peripheral, dilated airways (n = 3) and interlobular septa (n = 3). MIP and minimum intensity projection images added additional diagnostic findings to those on thin-section scans in 13 (65%) of 20 cases.

CONCLUSION

MIP and minimum intensity projection images of helical data sets may help diagnosis of a wide spectrum of diffuse lung diseases.

Differentiation of the ILO boundary chest roentgenograph (0/1 to 1/0) in asbestosis by high-resolution computed tomography scan, alveolitis, and respiratory impairment

High-resolution computed tomography (HRCT) scans have been advocated as providing greater sensitivity in detecting parenchymal opacities in asbestos-exposed individuals, especially in the presence of pleural fibrosis, and having excellent inter- and intraobserver reader interpretation. We compared the 1980 International Labor Organization (ILO) International Classification of the Radiographs of the Pneumoconioses for asbestosis with the high-resolution CT scan using a grid scoring system to better differentiate normal versus abnormal in the ILO boundary 0/1 to 1/0 chest roentgenograph. We studied 37 asbestos-exposed individuals using the ILO classification, HRCT grid scores, respiratory symptom questionnaires, pulmonary function tests, and bronchoalveolar lavage. We used Pearson correlation coefficients to evaluate the linear relationship between outcome variables and each roentgenographic method. The normal HRCT scan proved to be an excellent predictor of "normality," with pulmonary function values close to 100% for forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), total lung capacity (TLC), and carbon monoxide diffusing capacity (DLCO) and no increase in BAL inflammatory cells. Concordant HRCT/ILO abnormalities were associated with reduced FEV1/FVC ratio, reduced diffusing capacity, and alveolitis consistent with a definition of asbestosis. In our study, the ILO classification and HRCT grid scores were both excellent modalities for the assessment of asbestosis and its association with impaired physiology and alveolitis, with their combined use providing statistical associations with alveolitis and reduced diffusing capacity.

Unusual lymphoproliferative disorders in nine adults with HIV or AIDS: CT and pathologic findings

PURPOSE

To identify characteristic computed tomographic (CT) findings in unusual pulmonary lymphoproliferative disorders seen in adults with the human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS).

MATERIALS AND METHODS

The authors retrospectively reviewed the CT scans and pathologic specimens from nine patients with pulmonary lymphoproliferative disorders. CT scans were evaluated for nodules, reticulation, areas of ground-glass attenuation, consolidation, and bronchial disease. Changes seen in pathologic specimens were classified as consistent with classic lymphocytic interstitial pneumonitis (LIP), mucosa-associated lymphoid tissue lymphoma (MALTOMA), or atypical lymphoproliferative disorder (ALD). Immunopathologic results were reviewed when available.

RESULTS

Eight patients had AIDS. Five patients had classic LIP. One patient had MALTOMA, and three patients had ALD. Altogether, 2-4-mm-diameter nodules were the predominant CT finding in eight patients; these were peribronchovascular in four patients. The presence of interstitial nodules correlated with the pathologic finding of nodular disease in seven patients.

CONCLUSION

Familiarity with these AIDS-related disorders and their CT appearance should assist in the differential diagnosis.

Bronchiectasis: CT/clinical correlations

The association between bronchiectasis and human immunodeficiency virus infection, the resurgence of tuberculosis, especially in urban and immunocompromised patients, and the recognition of bronchiectasis as a manifestation of rejection in the transplant population are emerging clinical settings in which establishing the diagnosis of bronchiectasis is becoming increasingly important. High-resolution CT, by virtue of its well-established accuracy, is currently accepted as the optimal noninvasive means of diagnosing bronchiectasis. However, reliable diagnosis requires meticulous attention to technique and a thorough knowledge of potential pitfalls. These include, among others, respiratory and cardiac motion artifacts as well as effects of collimation and electronic windowing. It also is important to recognize diseases that may mimic the appearance of bronchiectasis as well as unusual manifestations of bronchiectasis that may obscure the diagnosis.

Airways and lung: correlation of CT with fiberoptic bronchoscopy

Recent advances in computed tomography (CT) and fiberoptic bronchoscopy (FOB) have led to confusion concerning the optimal use of these modalities, especially with regard to each other. The present review summarizes the current understanding of the role of CT in relation to FOB. Emphasis is placed on optimization of CT technique and basic principles of interpretation of the images. In addition, an in-depth evaluation is presented of the advantages and limitations of CT and FOB in the analysis of both focal and diffuse diseases of the airways and lung parenchyma.

T2-weighted MR imaging of the chest: comparison of electrocardiograph-triggered conventional and turbo spin-echo and nontriggered turbo spin-echo sequences

In 22 patients with a diverse range of thoracic abnormalities, T2-weighted magnetic resonance (MR) images of the chest were obtained with electrocardiograph (ECG)-triggered turbo spin-echo (TSE), ECG-triggered conventional spin-echo (CSE), and nontriggered TSE sequences, and the images were compared. A 5-point rating scale was used by three radiologists experienced in MR imaging of the chest to independently evaluate the images for (a) freedom from ghosting, (b) clarity of heart wall and cardiac chambers, (c) clarity of mediastinal structures, (d) conspicuity of abnormalities, and (e) overall image quality. Evaluations were analyzed with statistical methods. For freedom from ghosting, clarity of heart wall and cardiac chambers, clarity of mediastinal structures, and overall image quality, the ECG-triggered TSE images were rated higher than the TSE images, which, in turn, were rated higher than the ECG-triggered CSE images at the P = .05 level of significance. No significant differences were seen between the pulse sequences in the conspicuity of abnormalities, although some differences were observed in individual cases. Our results suggest that ECG-triggered TSE imaging provides improved, time-efficient T2-weighted images of the chest.

Cytomegalovirus pneumonitis: spectrum of parenchymal CT findings with pathologic correlation in 21 AIDS patients

PURPOSE

To identify characteristic features of cytomegalovirus (CMV) pneumonitis at computed tomography (CT), particularly markers that may help differentiate CMV from Pneumocystis carinii pneumonia.

MATERIALS AND METHODS

Bronchoalveolar lavage (BAL) and biopsy results in 21 patients with acquired immunodeficiency syndrome, cytopathologic evidence of CMV infection without other infections, and available CT scans were retrospectively evaluated. CT findings were correlated with radiographic and pathologic findings when available.

RESULTS

BAL findings were positive for CMV in only six cases, 13 patients had extrathoracic CMV infection, and 10 had Kaposi sarcoma. CT findings included ground-glass attenuation, dense consolidation, bronchial wall thickening or bronchiectasis, and interstitial reticulation without air-space disease (12 patients had discrete pulmonary nodules or masses). Biopsy revealed air-space disease as the dominant process in eight cases. Histopathologic findings correlated well with CT appearances.

CONCLUSION

CMV pneumonitis should be suspected in patients with either extrathoracic CMV or documented Kaposi sarcoma, especially when radiographic or CT evidence of pulmonary nodules or masses exists.

Helical computed tomography of the thorax. Clinical applications

Intuitively, any technique that minimizes the effects of respiratory motion, eliminates misregistration between scans, minimizes intravenous contrast requirements, and allows high quality multiplanar and 3-D image reconstruction is likely to have a tremendous impact on conventional notions concerning routine thoracic CT. Helical scanning is already of proved efficacy for vascular and airway imaging as well as for identifying and characterizing pulmonary nodules. It may be anticipated that the indications for the use of helical imaging will continue to expand. Of particular interest is the ongoing development of reconstruction algorithms that allow high-quality images to be obtained with rapid table incrementation while simultaneously reducing radiation exposure. Given the intrinsically high contrast of structures within the thorax coupled with the disadvantages that result from respiratory motion, it is not unreasonable to conclude that within the near future volumetric techniques will be the standard for nearly all CT applications within the thorax.

Hemoptysis: prospective high-resolution CT/bronchoscopic correlation

The precise roles of fiberoptic bronchoscopy (FOB) and computed tomography (CT) of the chest in the evaluation of patients presenting with hemoptysis have not been clearly defined. On the assumption that both procedures would likely provide unique and complementary information, a prospective study with blinded interpreters using a modified high-resolution CT technique (HRCT) and FOB was designed to evaluate 57 consecutive patients admitted to Bellevue Hospital with hemoptysis. Etiologies included bronchiectasis (25 percent), tuberculosis (16 percent), lung cancer (12 percent), aspergilloma (12 percent), and bronchitis (5 percent): in an additional 5 percent of cases, hemoptysis proved to be due miscellaneous causes, while in 19 percent hemoptysis proved to be cryptogenic. Patients with lung cancer all were at least 50 years old, smoked an average of 78 pack-years, and had less severe hemoptysis but of longer duration. All had conditions diagnosed both by HRCT and FOB. High-resolution CT proved of particular value in diagnosing bronchiectasis and aspergillomas, while FOB was diagnostic of bronchitis and mucosal lesions such as Kaposi's sarcoma. Fiberoptic bronchoscopy localized bleeding in only 51 percent of cases. The high sensitivity of CT in identifying both the intraluminal and extraluminal extent of central lung cancers in conjunction with its value in diagnosing bronchiectasis suggest that CT should be obtained prior to bronchoscopy in all patients presenting with hemoptysis.

Accessory cardiac bronchus: CT features and clinical significance

PURPOSE

The accessory cardiac bronchus is a rare congenital anomaly of the tracheobronchial tree that arises from the medial wall of the bronchus intermedius. This report documents the computed tomographic (CT) appearance of this anomaly.

MATERIALS AND METHODS

Six patients with this anomaly were identified. All six underwent CT; three underwent correlative bronchoscopy, and one had both bronchoscopic and surgical confirmation.

RESULTS

In all six cases, a distinct airway could be identified originating from the medial wall of the bronchus intermedius. Associated lung parenchymal tissue was identified in four cases, while in three cases a discrete soft-tissue mass was seen, presumably representing vascularized bronchial or vestigial parenchymal tissue. In two cases, the lumen of the airway was filled with debris.

CONCLUSION

Recognition of this anomaly is important, as associated clinical complications, including recurrent episodes of both infection and hemoptysis, may be anticipated in a small percentage of patients.

Intrathoracic adenopathy associated with pulmonary tuberculosis in patients with human immunodeficiency virus infection

The role of computed tomography (CT) in the diagnosis of mediastinal tuberculous lymphadenitis was evaluated retrospectively in 25 human immunodeficiency virus (HIV)-infected patients (19 had AIDS). In all cases, the diagnosis of tuberculosis was established by mycobacterial culture and/or histologic evaluation. The most characteristic CT finding was the presence of low-density mediastinal and hilar lymph nodes in 16 of 19 (84 percent) patients with AIDS and four of six (67 percent) HIV-seropositive patients without AIDS. Marked enhancement of the periphery of nodes was identified in five cases, all in patients with documented AIDS. In most cases, lymphadenopathy proved to be massive, presenting as extensive, heterogenous soft-tissue lesions, presumably the result of coalescence of groups of matted nodes. We conclude that low-density mediastinal and/or hilar lymph nodes on CT, while not pathognomonic, is sufficiently characteristic for tuberculosis to warrant empiric antituberculosis therapy pending results of cultures.

AIDS associated bronchiectasis: CT features

The occurrence of bronchiectasis has only rarely been noted among the protean manifestations of HIV infection in the lungs. We retrospectively identified bronchiectasis on CT scans in 12 HIV + and/or AIDS patients in the absence of either documented mycobacterial infection or a history of prior recurrent pyogenic infection. Pneumonitis was documented in 10 of 12 cases. In eight cases, bronchiectasis was associated with episodes of pyogenic infection; four of these patients also had documented opportunistic infections, including three cases of Pneumocystis carinii pneumonia (PCP). Two patients had infection due solely to PCP. In two cases, bronchiectasis was found in association with one case each of lymphocytic interstitial pneumonitis and nonspecific interstitial pneumonitis, respectively. Although the true incidence of bronchiectasis in this population remains to be established, in our experience bronchiectasis should be considered among the varied pulmonary manifestations of HIV infection. Furthermore, the seemingly rapid development and extent of bronchiectasis in this population suggest an accelerated form of the disease.

Bronchiectasis: CT evaluation

CT is the imaging method of choice after standard chest radiography for examining patients with suspected bronchiectasis. In most institutions throughout the world, CT has largely eliminated the need for bronchography in the diagnosis of bronchiectasis. Nonetheless, controversy persists concerning the overall accuracy of CT. In an effort to improve overall diagnostic accuracy, we review the wide range of CT appearances of this protean disorder, and emphasize potential problems and technical pitfalls that may arise in routine clinical imaging.

Aortic aneurysm and dissection: normal MR imaging and CT findings after surgical repair with the continuous-suture graft-inclusion technique

The normal range of postoperative imaging findings are described in 34 asymptomatic patients studied 5-66 months (mean, 28 months) after undergoing the continuous-suture graft-inclusion technique for repair of aortic aneurysms (n = 20) and dissections (n = 14) involving the ascending aorta. All 34 patients underwent magnetic resonance (MR) imaging, and 24 patients also underwent computed tomography (CT). Perigraft thickening was seen in 19 patients (56%) with MR imaging and in eight patients (33%) with CT. Flow outside the graft but contained within the native wrap was noted in five patients (15%) with MR imaging and in four patients (17%) with contrast material-enhanced CT. Thrombus was identified outside the graft and within the wrap in seven patients (21%) with MR imaging and in six patients (25%) with CT. Mass effect on the graft was depicted in four patients (12%) with MR imaging and in three patients (13%) with CT. Of the 14 patients who underwent repair of aortic dissections, an intimal flap was seen distal to the graft in seven of the 14 (50%) evaluated with MR imaging and in four of the 10 (40%) evaluated with contrast-enhanced CT. An accurate postoperative imaging evaluation requires precise knowledge of the surgical technique performed and its anatomic consequences.

Variables affecting pulmonary nodule detection with computed tomography: evaluation with three-dimensional computer simulation

To meaningfully evaluate factors determining the overall accuracy of computed tomography (CT) for identifying pulmonary nodules, computer-generated nodules were superimposed on normal CT scans and interpreted independently by three experienced chest radiologists. Variables evaluated included nodule size, shape, number, density, location, edge characteristics, and relationship to adjacent vessels, as well as technical factors, including slice thickness and electronic windowing. The overall sensitivity in identifying nodules was 62% and the specificity was 80%. On average, the observers identified 56, 67, and 63% of nodules on 1.5-, 5-, and 10-mm-thick sections, respectively (p = 0.037). Nodules were more difficult to identify on 1.5-mm-thick sections. On average, observers identified 1, 48, 82, and 91% of nodules < 1.5, < 3, < 4.5, and < 7 mm in diameter, respectively (p < 0.001). Other factors that made a significant contribution (p < 0.01) in identifying nodules, as determined by linear discriminant function analysis, included nodule location, angiocentricity, and density. We concluded that computer-generated nodules can be used to assess a large number of imaging variables. We anticipate that this approach will be of considerable utility in assessing the accuracy of interpretation of a wide range of pathologic entities as well as in optimizing three-dimensional scan protocols within the thorax.

The left atrial catheter: its uses and complications

The authors describe the radiographic appearance of the left atrial catheter, a widely used postsurgical intracardiac device. Recognition of the characteristic appearance of this catheter should be of value in detection of potential complications, including line fracture with resultant retention and/or embolization, infection, prosthetic valve dysfunction, and even cardiac tamponade.

Thoracic disease in the immunocompromised patient

Thoracic disease in the HIV negative immunocompromised host is most frequently caused by infection. Patterns of involvement produced on the chest radiograph include (1) lobar or segmental consolidation, (2) nodules with rapid growth and/or cavitation, and (3) diffuse lung disease. The lung also may be directly involved by lymphoma, metastases, drug reactions, radiation pneumonitis, or nonspecific interstitial pneumonitis. The lung is a frequent target organ for opportunistic infections in AIDS patients, particularly of Pneumocystis carinii pneumonia and tuberculosis. Computed tomography may be particularly helpful in these patients in the detection of early disease and in the characterization of patterns and extent of involvement as well as complications.

High resolution CT findings in miliary lung disease

High-resolution CT (HRCT) and chest radiographs were compared in nine patients with miliary lung disease. In all cases, miliary disease was documented to be infectious in etiology; six of these patients proved to be human immunodeficiency virus (HIV) positive. A mixture of both sharply and poorly defined 1-3 mm nodules was seen in all cases, many of the latter having an appearance indistinguishable from airspace nodules. Other features attributable to the presence of nodules included nodular interlobular septae, nodular irregularity of vessels, subpleural dots, and studded fissures. Diffuse intra- and interlobular septal thickening also proved common, seen in all but one case (91%). Based on limited HRCT-pathologic correlation, CT findings appear primarily to be due to granulomatous foci developing in a seemingly random distribution involving both pulmonary airspaces as well as the interstitium. It is concluded that in the appropriate clinical setting this constellation of findings is characteristic of miliary disease; the role of HRCT especially in the early diagnosis of miliary disease in HIV positive patients remains to be determined prospectively.

Pulmonary manifestations of AIDs. CT and radiographic correlations

To date, few reports have attempted to correlate plain radiographic findings with computed tomography (CT) in assessing pulmonary disease in patients who have acquired immunodeficiency syndrome (AIDS). This report focuses on the most common pulmonary manifestations, with particular emphasis placed on those entities for which there is a potential role for CT. This includes identification of occult disease, especially the early diagnosis of Pneumocystis carinii pneumonia, as well as identification of unsuspected lung abscesses and cavities; characterization of diffuse parenchymal disease in patients who have abnormal radiographs; identification and characterization of mediastinal lymphadenopathy, especially in differentiating between neoplastic and non-neoplastic causes; and finally, use of CT to perform CT-guided transthoracic needle biopsies.

Myocardial abscess resulting in a pseudoaneurysm: case report

This report describes the diagnostic workup of a case of a pseudoaneurysm of the heart resulting from Staphylococcal pericarditis and/or abscesses of the myocardium. The pericardial effusion and myocardial abscesses were detected on 2D echocardiography and computed tomography. The resulting pseudoaneurysm could be demonstrated on magnetic resonance imaging and color Doppler ultrasound, and confirmed by left ventriculography. Color-encoded Doppler ultrasound alone would have provided the definitive diagnosis of the aneurysm.

Cystic fibrosis: scoring system with thin-section CT

The progression of lung disease in patients with cystic fibrosis (CF) was evaluated with chest radiography. The severity and extent of the various radiographic changes were scored with the Chrispin or the Birmingham method, which involves the use of imprecise and subjective terms, such as line shadows, large pulmonary shadows, and nodular cystic lesions. Although computed tomography (CT) has been shown to be helpful in the evaluation of lung disease in CF, no scoring system or other objective criteria have been developed for the evaluation of the wide range of pulmonary changes in these patients. A CT scoring system was devised that incorporates all of the changes seen in the lungs of patients with CF. Such a scoring system may facilitate objective evaluation of existing and newly developed therapeutic regimens and may be a valuable tool in the preoperative evaluation of patients being considered for lobectomy or bullectomy and in the selection of patients for lung transplantation.

Radiographic evaluation of focal lung disease

Optimal clinical management of patients with focal lung pathology necessitates thorough familiarity with basic concepts in imaging. Over the past decade, radiologic evaluation has undergone rapid change, reflecting considerable growth in imaging technology. As this article discusses and illustrates at length, improvements in computed tomography technology in particular have resulted in a significant alteration in our approach to both the diagnosis and treatment of patients with focal lung disease.

Thoracic magnetic resonance imaging

In our experience, MR has served largely as a problem-solving device, especially in those cases in which CT has proved equivocal. Magnetic resonance has been especially efficacious in evaluating cardiovascular pathology. Virtually the entire spectrum of aortic disease can be assessed accurately, making MR a reasonable alternative to CT or angiography in most cases. Indications for the use of MR in patients with thoracic neoplasia have also emerged. Magnetic resonance is more accurate than CT in assessing invasion of the chest wall and mediastinum. As a consequence, MR should be considered the imaging procedure of choice in patients with suspected Pancoast tumors. In some patients with lymphoma, MR can make a unique contribution by evaluating the response to therapy. Magnetic resonance also can be of value in assessing patients with signs of venous obstruction, especially when there is a contraindication to the use of intravenous contrast medium. Magnetic resonance is as accurate as CT in assessing most benign mediastinal pathology. The former study can easily differentiate atherosclerotic vessels or aneurysms from enlarged lymph nodes or masses, frequently obviating a more invasive study. It is especially efficacious in evaluating patients with cystic lesions, especially those with complex cysts not clearly of water density. In the hilum, MR can differentiate prominent hilar vessels from adenopathy or masses as reliably as CT. Again, in patients with renal failure or those who have documented allergies to iodinated contrast medium, MR should be the imaging procedure of choice to evaluate suspicious hila identified on plain chest radiographs. Magnetic resonance also can be used to differentiate central obstructing hilar tumors from peripheral collapsed lung. In certain cases, these findings may help determine resectability by demonstrating encasement of hilar and mediastinal vessels as well as the central airways. It should be anticipated that as technologic improvements continue to be made, MR will assume an increasingly important role in the imaging of thoracic disease.

Hemoptysis: CT-bronchoscopic correlations in 58 cases

Computed tomographic (CT) and chest radiographic findings were retrospectively correlated with those found at fiberoptic bronchoscopy (FOB) in 58 patients presenting with hemoptysis. Abnormalities involving the airways were depicted by CT in a total of 28 cases (48%). In 18 of these (31% of the total group of 58), focal abnormalities involving the central airways were identified (17 were subsequently proved to be malignant) and in 10 (17% of the total), CT showed bronchiectasis. Focal airway abnormality was shown by FOB in 18 cases (31%); all of these were depicted with CT. Malignancy was diagnosed in 24 patients, including three in whom results of FOB were normal but malignant cells were identified at transbronchial biopsy. CT abnormalities were identified in all cases of malignancy. In 10 of 21 cases (48%) of non-small cell lung cancer, CT allowed definitive staging by documenting either direct mediastinal invasion and/or metastatic disease, while FOB allowed definitive staging in only three cases. CT studies provided no false-negative results. It is concluded that when carefully performed, CT may be an effective modality for evaluating patients presenting with hemoptysis.

Computed tomography and bronchoscopy in chest radiographically occult main-stem neoplasm diagnosis and Nd-YAG laser treatment in 8 patients

We studied 8 adult patients with variable symptoms of cough, dyspnea, stridor, wheezing, or hemoptysis. Fiberoptic bronchoscopy in all showed complete or nearly complete endobronchial obstruction of a main-stem bronchus by neoplasm with a mean bronchial diameter of 1.9 mm +/- 1.6 mm (mean +/- standard deviation). In 4 patients, a lobar bronchus was also completely obstructed. No mass was visible on chest radiographs of any patient; however, computed tomography in each showed main-stem endobronchial obstruction, lobar obstruction (4 instances in 3 patients), and in 6 patients hypoperfusion of the involved lung. Computed tomographic scan showed additional abnormalities that were unsuspected on viewing chest radiographs or at bronchoscopy, including mediastinal adenopathy in 3 patients and an extraluminal tumor component in 4. After therapy with Nd-YAG laser, main-stem airway diameter increased to a mean of 9.6 mm +/- 1.0 mm (P less than .05) and pulmonary functions improved. Results suggest the complementary role of computed tomography and fiberoptic bronchoscopy in the detection and laser-treatment planning of chest radiographically occult severe neoplastic obstruction of the main-stem bronchus.

Pulmonary artery sarcoma: evaluation using Gd-DTPA

Primary malignant tumors of the pulmonary arteries occur infrequently and diagnosis is often delayed since symptoms are nonspecific. We present a case of pulmonary artery sarcoma and its interesting magnetic resonance findings.