Faculty Bibliography

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

Viruses and Pneumocystis carinii are significant causes of pneumonia in immunocompromised patients, particularly patients with impaired cell-mediated immunity. They are often simultaneously considered in the differential diagnosis of diffuse pneumonitis in these patients and, because radiographic appearances and the periods of vulnerability to these infections may overlap, may be difficult to differentiate. This article will correlate radiographic findings to evolving histopathologic changes in select specific infections, as they affect three different immune impaired populations: (a) acquired immunodeficiency syndrome, (b) immunosuppression secondary to therapy for underlying malignancy or with solid organ transplantation, and (c) immune impairment in the bone marrow transplant patient. Appreciation of the specific clinical setting in which to consider these infections will be emphasized

Two cases of primary multifocal tuberculous osteomyelitis with involvement of the rib cage are presented. The lungs were normal and the appearance of the skeletal lesions did not suggest tuberculosis. These lesions were predominantly lytic, with minimal soft tissue involvement. Tuberculosis should be high in the differential diagnosis of multiple destructive bone lesions, especially in patients from regions where tuberculosis is endemic

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

PURPOSE: To assess the computed tomographic (CT) and histologic findings of intrathoracic lymphoproliferative disease (LPD) associated with the Epstein-Barr virus (EBV). MATERIALS AND METHODS: The authors retrospectively reviewed the CT scans of the chest and the pathologic specimens obtained in 24 patients with histologically proved intrathoracic LPD and with positive serologic findings or immunohistochemical staining for EBV. Five patients had acquired immunodeficiency syndrome (AIDS); one had common variable immune deficiency; and 18 were receiving immunosuppressive therapy for heart, lung, or heart-lung (n =15) or bone marrow (n = 2) transplantation and vasculitis (n = 1). RESULTS: Final diagnoses included malignant lymphoma (n = 15), polyclonal LPD (n = 8), and hyperplasia of bronchus-associated lymphoid tissue (n = 1). CT findings included multiple nodules (n = 21), lymphadenopathy (n = 9), areas of groundglass opacification (n = 8), septal thickening (n = 7), consolidation (n = 5), pleural effusion (n = 4), and solitary endobronchial lesion (n = 2). The nodules were 2-4 cm in diameter, involved mainly the middle and lower lung zones, and frequently had a predominantly peribronchovascular (n = 15) or subpleural (n = 14) distribution. CONCLUSION: EBV-associated LPD may range from benign lymphoid hyperplasia to high-grade lymphoma. The most common CT manifestation consists of multiple nodules, frequently in a predominantly peribronchovascular or subpleural distribution

Despite encouraging recent treatment advances, HIV and AIDS-related pulmonary complications will continue to present a diagnostic and therapeutic challenge. Streamlined, cost-effective management of these patients is increasingly important in the current medical economic environment. This article presents an approach to the diagnosis of AIDS-related pulmonary disease, emphasizing optimal integration of imaging modalities into specific, practical, cost-effective pathways. The imaging findings of common diseases, both infectious and noninfectious, are summarized, The importance of clinical and demographic information to accurate radiographic interpretation and diagnostic evaluation is emphasized

This article reviews the changing trends observed in AIDS patients over the course of the epidemic. The spectrum of diseases of the chest associated with HIV infection is vast and varied. To generate a useful differential diagnosis based on imaging findings, the radiologist must appreciate shifts in disease prevalence and epidemiology and appreciate changing radiographic manifestations of many of these diseases. Imaging findings, both with chest radiography and CT scan, are summarized and the importance of integration of clinical information in interpreting these images and generating a reasonable differential diagnosis is emphasized

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 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

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