Faculty Bibliography

High-resolution computed tomography (HRCT) allows a detailed assessment of the anatomy and pathology of the pulmonary parenchyma. However, numerous potential pitfalls exist that can hinder or preclude accurate interpretation of HRCT images. These sources of potential diagnostic error can be systematically evaluated with respect to the major categories of HRCT abnormalities: (1) increased parenchymal attenuation, (2) linear opacities and interstitial disease, (3) nodular lung disease, and (4) holes in the lung. Accurate HRCT interpretation depends on the correct recognition and characterization of imaging abnormalities. Technical factors that enhance or limit scan interpretation, HRCT features of subtle disease, and imaging mimics of commonly observed pathology are addressed in detail with regard to each of the above categories of disease. Common pitfalls are illustrated and explained in an effort to increase general awareness of these sources of real and potential diagnostic confusion

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

OBJECTIVE:To determine the outcome of areas of ground-glass attenuation and assess disease progression on serial high-resolution CT (HRCT) scans of patients with biopsy specimen-proved usual interstitial pneumonia (UIP) and desquamative interstitial pneumonia (DIP). MATERIALS AND METHODS/METHODS:Twelve patients with biopsy specimen-proved UIP and 11 patients with biopsy specimen-proved DIP who had initial and follow-up HRCT scans (median interval, 10 months) were reviewed. Eleven patients with UIP and 11 with DIP received treatment between the initial and follow-up CT scans. The scans were evaluated for the presence and extent of ground-glass attenuation, irregular linear opacities and honeycombing, and overall extent of parenchymal involvement. RESULTS:On initial CT scans, all 12 patients with UIP had areas of ground-glass attenuation (mean +/- SD extent, 30 +/- 16%) and irregular lines (mean +/- SD extent, 17 +/- 7%) and 10 patients had honeycombing (mean +/- SD extent, 10 +/- 6%). All 11 patients with DIP had areas of ground-glass attenuation on initial HRCT scans (mean +/- SD extent, 51 +/- 26%), 5 patients had irregular linear opacities (mean +/- SD extent, 5 +/- 5%), and 1 patient had honeycombing. Nine of the 12 patients with UIP showed increase in the extent of ground-glass attenuation (n = 6) or progression to irregular lines (n = 2) or honeycombing (n = 4) on follow-up as compared with only 2 patients with DIP who showed progression to irregular lines (n = 1) or honeycombing (n = 1) (p < 0.01 chi 2 test). CONCLUSION/CONCLUSIONS:In patients with UIP, areas of ground-glass attenuation usually increase in extent or progress to fibrosis despite treatment. Areas of ground-glass attenuation in most patients with DIP remain stable or improve with treatment.

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

OBJECTIVE, The purpose of this study was to compare the sensitivity and specificity of chest radiography with those of CT in the detection of pulmonary infections and tumors in patients with AIDS, MATERIALS AND METHODS. The study was retrospective and included the radiographs and CT scans of 139 patients, Eighty-nine had one proven thoracic complication, 17 had two proven thoracic complications, and 33 had no active intrathoracic disease at the time of the examinations, The radiographs and CT scans were interpreted blindly by two independent observers from different institutions, The observers assessed for the presence or absence of intrathoracic disease and recorded the most likely diagnosis and the degree of confidence in that diagnosis. RESULTS, The patients were more commonly correctly identified as having or not having intrathoracic disease on the basis of CT findings than on the basis of radiographic findings (p < .01, chi-square test). Of the 106 patients with intrathoracic complications, 90% (191 of 212 interpretations) were correctly identified by the two observers on the radiograph and 96% (204 of 212 interpretations) at CT, Of 33 patients without intrathoracic disease, 73% (48 of 66 interpretations) were correctly identified at radiography and 86% (57 of 66 interpretations) at CT. Of 89 patients with one proved thoracic complication, the observers were confident in their first-choice diagnosis in 34% of the cases (61 of 178 interpretations) at chest radiography and in 47% (83 of 178 interpretations) at CT. This diagnosis was correct in 67% (41 of 61) of confident radiographic interpretations as compared with 87% (72 of 83) of interpretations at CT (p < .01,chi-square test). CONCLUSION. CT is superior to chest radiography in allowing identification of patients with and without thoracic disease and in the differential diagnosis of pulmonary complications of patients with AIDS, However, the improvement in differential diagnosis is modest. Because in most cases the radiographs and CT scans were obtained as part of the clinical evaluation, the study is probably biased toward problematic clinical cases, In the majority of patients, the chest radiograph provides adequate information and CT is not warranted

PURPOSE: To describe the varied clinical manifestations and imaging findings encountered in bacillary angiomatosis, an infectious complication of the acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Clinical, imaging, and histopathologic findings in nine men (aged 26-50 years) with AIDS and bacillary angiomatosis were described. This condition often manifests as vascular skin lesions that resemble those of Kaposi sarcoma, fever, and anemia and is due to infection with Bartonella (Rochalimaea) henselae. RESULTS: Common imaging findings included lung nodules, mediastinal adenopathy, peripheral adenopathy, pleural effusions, ascites, abdominal adenopathy, soft-tissue masses, and low-attenuation lesions in the liver and/or spleen. Most notably, nodes and soft-tissue lesions were dramatically enhanced with injection of contrast material, which is presumably because the lesions are composed to a large extent of well-formed capillaries. CONCLUSION: Bacillary angiomatosis, a treatable infection, should be considered in patients with AIDS, particularly when Kaposi sarcoma is suspected clinically.

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

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

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

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