Lymphocytic interstitial pneumonia: thin-section CT findings in 22 patients.

PURPOSE: To assess the thin-section computed tomographic (CT) findings of lymphocytic interstitial pneumonia. MATERIALS AND METHODS: The study included 22 patients (five men, 17 women; age range, 24-83 years; mean age, 50 years) with biopsy-proved lymphocytic interstitial pneumonia. The CT scans were obtained by using 1-3-mm collimation and reconstructed by using a high-spatial-frequency algorithm. RESULTS: The predominant abnormalities consisted of areas of ground-glass attenuation and poorly defined centrilobular nodules present in all 22 patients and subpleural small nodules seen in 19 patients. Other common findings included thickening of bronchovascular bundles (n - 19), interlobular septal thickening (n = 18), cystic airspaces (n = 15), and lymph node enlargement (n = 15). Less common findings included large nodules, emphysema, airspace consolidation, bronchiectasis, architectural distortion, honeycombing, and pleural thickening. CONCLUSION: Lymphocytic interstitial pneumonia is characterized by the presence of ground-glass attenuation, poorly defined centrilobular nodules, and thickening of the interstitium along the lymphatic vessels. Lymph node enlargement is more common than previously recognized; it was seen in 68% of patients.     

Rheumatoid arthritis-related lung diseases: CT findings

PURPOSE: To evaluate computed tomographic (CT) findings of rheumatoid arthritis-related lung disease and categorize findings according to pathologic features. MATERIALS AND METHODS: CT scans obtained in 63 patients (27 men, 36 women; mean age, 61.7 years +/- 11.2 [SD]; range, 28-81 years) with rheumatoid arthritis were assessed. Mean duration of disease was 7.6 years +/- 9.2. Lung parenchymal abnormalities that included airspace consolidation, ground-glass opacity (GGO), reticulation, honeycombing, nodules, bronchiectasis, and air trapping were assessed retrospectively by two chest radiologists. Final decision was reached with consensus of these radiologists and a third radiologist. Patients were classified according to the predominant CT pattern. One of the chest radiologists and a pulmonary pathologist compared CT findings with pathologic findings in 17 patients. Interobserver agreement between the first two radiologists was assessed. Correlation between CT finding extent score and pulmonary function test results was estimated with Spearman rank correlation coefficient. RESULTS: GGO (57 [90%] patients) and reticulation (62 [98%] patients) were the most common CT features. Four major CT patterns were identified: usual interstitial pneumonia (n = 26), nonspecific interstitial pneumonia (n = 19), bronchiolitis (n = 11), and organizing pneumonia (n = 5). Usual interstitial pneumonia and nonspecific interstitial pneumonia CT patterns overlapped; GGO was more extensive in patients with nonspecific interstitial pneumonia CT pattern (P =.028). In 17 patients who underwent biopsy, CT findings reflected pathologic findings. Exceptions were two patients classified with usual interstitial pneumonia at CT but with nonspecific interstitial pneumonia at pathologic analysis; one patient, with nonspecific interstitial pneumonia at CT but desquamative interstitial pneumonia at pathologic analysis; and one patient, with lymphoid interstitial pneumonia at CT but nonspecific interstitial pneumonia at pathologic analysis. CONCLUSION: Rheumatoid arthritis is associated with four CT patterns: usual interstitial pneumonia, nonspecific interstitial pneumonia, bronchiolitis, and organizing pneumonia. The most common CT features of rheumatoid arthritis-related lung disease were GGO and reticulation.     

Lung diseases in patients with common variable immunodeficiency: chest radiographic, and computed tomographic findings

OBJECTIVE: To evaluate chest radiographic and computed tomographic (CT) findings of lung disease related to common variable immunodeficiency. METHODS: Thirty-five chest radiographs and 30 CT scans of 46 patients were assessed. Lung parenchymal abnormalities that were evaluated included airspace consolidation, ground-glass attenuation, nodules, bronchiectasis, and air trapping. RESULTS: On CT, ground-glass attenuation and nodules were the most frequent findings, observed in 60% (n = 18/30) and 83% (n = 25/30), respectively. Three major CT patterns were identified: airway disease (n = 13), nodules (n = 8), and parenchymal opacification (n = 6). All 13 patients with airway disease showed centrilobular opacities. One patient with peribronchial nodules showed lymphoid interstitial pneumonia, and 1 with randomly distributed nodules showed noncaseating granulomas. Patients with a CT pattern of parenchymal opacification showed lower lung predominance; surgical biopsies showed organizing pneumonia in 1 patient and lymphoid interstitial pneumonia with nonnecrotizing granulomas in another. CONCLUSIONS: Common variable immunodeficiency is associated with 3 major CT patterns: airway disease, nodules, and parenchymal opacification.     

Mycoplasma pneumoniae pneumonia: radiographic and high-resolution CT features in 28 patients

OBJECTIVE: The aim of the study was to compare the radiographic and the high-resolution CT findings of Mycoplasma pneumoniae pneumonia. MATERIALS AND METHODS: The chest radiographs and 1.5-mm collimation CT scans obtained in 28 patients with serologically proven M. pneumoniae pneumonia were retrospectively reviewed. The radiographs and CT scans were analyzed independently by two observers. RESULTS: The most common finding on radiography was the presence of air-space opacification (n = 24), which was patchy and segmental (n = 9) or nonsegmental (n = 15) in distribution. On high-resolution CT, areas of ground-glass attenuation were seen in 24 patients (86%) and air-space consolidation in 22 (79%). In 13 patients (59%), the areas of consolidation had a lobular distribution evident on CT. Nodules were seen more commonly on high-resolution CT (25 of 28 patients, 89%) than on radiography (14 patients, 50%) (p < 0.01, chi-square test). In 24 (86%) of the 28 patients, the nodules had a predominantly centrilobular distribution on CT. Thickening of the bronchovascular bundles was identified more commonly on CT (23 of 28 patients, 82%) than on radiography (five patients, 18%) (p < 0.01, chi-square test). CONCLUSION: The lobular distribution, centrilobular involvement, and interstitial abnormalities in M. pneumoniae pneumonia are often difficult to recognize on radiography but can usually be seen on high-resolution CT.     

Radiographic and high-resolution CT findings of influenza virus pneumonia in patients with hematologic malignancies

OBJECTIVE: We sought to describe the radiographic and high-resolution CT findings of influenza virus pneumonia in patients with hematologic malignancies. CONCLUSION: Radiologic findings of influenza virus pneumonia in immunocompromised patients consist of patchy or confluent consolidation and nodular opacities on chest radiography and ground-glass attenuation, consolidation, centrilobular nodules, and branching linear opacities on high-resolution CT.     

Chronic pulmonary paracoccidioidomycosis (South American blastomycosis): high-resolution CT findings in 41 patients.

OBJECTIVE: To assess the pulmonary parenchymal findings on high-resolution CT in 41 patients with the chronic form of paracoccidioidomycosis (South American blastomycosis). SUBJECTS AND METHODS: The study included 41 consecutive patients in whom chronic paracoccidioidomycosis had been proven. All patients underwent high-resolution CT (1-mm collimation, high-spatial-frequency reconstruction algorithm) at 12 equally spaced intervals through the chest. The images were analyzed by two radiologists, and each final decision was reached by consensus. RESULTS: Thirty-eight (93%) of the 41 patients had CT scans with abnormal findings. The findings included interlobular septal thickening in 36 patients (88%), 1-25 mm diameter nodules in 34 (83%), peribronchovascular interstitial thickening in 32 (78%), centrilobular opacities in 26 (63%), intralobular lines in 24 (59%), ground-glass opacities in 14 (34%), cavitation in seven (17%), air-space consolidation in five (12%), traction bronchiectasis in 34 (83%), and paracicatricial emphysema in 28 (68%). In approximately 90% of patients, the abnormalities were bilateral and symmetrical and involved all lung zones. CONCLUSION: High-resolution CT findings of paracoccidioidomycosis consist predominantly of interstitial abnormalities and nodules associated with traction bronchiectasis and paracicatricial emphysema in a bilaterally symmetrical distribution.     

High-resolution CT findings of respiratory syncytial virus pneumonia after bone marrow transplantation

OBJECTIVE: The aim of this study was to describe the high-resolution CT findings of respiratory syncytial virus pneumonia in 20 patients who had undergone allogeneic bone marrow transplantation. MATERIALS AND METHODS: The study included 20 consecutive patients who developed respiratory syncytial virus pneumonia after bone marrow transplantation and who had high-resolution CT of the chest performed within 24 hr after the onset of symptoms. The CT scans were reviewed by two chest radiologists who assessed the pattern and distribution of findings. RESULTS: Bone marrow transplantation was performed on 12 male and eight female patients ranging from 3 to 48 years old (mean age, 25 years) for treatment of various forms of leukemia (n = 12), severe aplastic anemia (n = 6), Fanconi's syndrome (n = 1), and paroxysmal nocturnal hemoglobinuria (n = 1). Sixteen patients (80%) had abnormal CT findings. The predominant patterns of abnormality on high-resolution CT scans were small centrilobular nodules (10/20, 50%), air-space consolidation (7/20, 35%), ground-glass opacities (6/20, 30%), and bronchial wall thickening (6/20, 30%). The abnormalities were distributed in the central and peripheral areas of the lungs in nine cases, only in the periphery in five cases, and only in the central regions in two cases. The abnormalities were bilateral and asymmetric in distribution in 13 patients, bilateral and symmetric in two patients, and unilateral in one patient. CONCLUSION: The most common high-resolution CT findings in patients with respiratory syncytial virus pneumonia after bone marrow transplantation consist of small centrilobular nodules and multifocal areas of consolidation and ground-glass opacities in a bilateral asymmetric distribution.     

Can acute interstitial pneumonia be differentiated from bronchiolitis obliterans organizing pneumonia by high-resolution CT?

PURPOSE: In the early stages, clinical and chest radiographic findings of acute interstitial pneumonia (AIP) are often similar to those of bronchiolitis obliterans organizing pneumonia (BOOP). However, patients with AIP have a poor prognosis, while those with BOOP can achieve a complete recovery after corticosteroid therapy. The objective of this study was to identify differences in high-resolution CT (HRCT) findings between the two diseases. METHODS: The study included 27 patients with AIP and 14 with BOOP who were histologically diagnosed [open-lung biopsy (n=7), autopsy (n=17), transbronchial lung biopsy (n=17)]. The frequency and distribution of various HRCT findings for each disease were retrospectively evaluated. RESULTS: Traction bronchiectasis, interlobular septal thickening, and intralobular reticular opacities were significantly more prevalent in AIP (92.6%, 85.2%, and 59.3%, respectively) than in BOOP (42.9%, 35.7%, and 14.3%, respectively) (p<0.01). Parenchymal nodules and peripheral distribution were more prevalent in BOOP (28.6% and 57.1%, respectively) than in AIP (7.4% and 14.8%, respectively) (p<0.01). Areas with ground-glass attenuation, air-space consolidation, and architectural distortion were common in both AIP and BOOP. CONCLUSION: For a differential diagnosis of AIP and BOOP, special attention should be given to the following HRCT findings: traction bronchiectasis, interlobular septal thickening, intralobular reticular opacities, parenchymal nodules, pleural effusion, and peripheral zone predominance.     

Bronchiolitis obliterans organizing pneumonia: CT features in 14 patients

Bronchiolitis obliterans organizing pneumonia is a disease characterized by the presence of granulation tissue within small airways and the presence of areas of organizing pneumonia. We retrospectively reviewed the chest radiographs, CT scans, and biopsy specimens in 14 consecutive patients with proved bronchiolitis obliterans organizing pneumonia. Six patients were immunocompromised because of leukemia or bone-marrow transplantation. In all patients, 10-mm collimation CT scans were available. In 11 of the 14 patients, select 1.5-mm scans were obtained. The CT findings included patchy unilateral (n = 1) or bilateral air-space consolidation (n = 9), small nodular opacities (n = 7), irregular linear opacities (n = 2), bronchial wall thickening and dilatation (n = 6), and small pleural effusions (n = 4). All patients had areas of air-space consolidation, small nodules, or both. A predominantly subpleural distribution of the air-space consolidation was apparent on the radiographs of two patients and on CT scans of six. Pathologically, the nodules and the consolidation represented different degrees of inflammation in bronchioles, alveolar ducts, and alveoli. Although most of the findings were apparent on the radiographs, the CT scans depicted the anatomic distribution and extent of bronchiolitis obliterans organizing pneumonia more accurately than did the plain chest radiographs.     

Lymphoma of the lung: CT findings in 31 patients

Lymphomatous involvement of the lungs is often a difficult clinical and radiologic diagnosis to make, yet is often critical in determining treatment. To better define the CT appearance of pulmonary lymphoma, we undertook a retrospective review of 31 patients with recurrent or secondary non-Hodgkin lymphoma or Hodgkin disease and lung parenchymal involvement on CT scans. Diagnoses were confirmed either by lung biopsy or by disease regression or progression with appropriate therapy. The CT scans were evaluated for the following findings: (1) nodules less than 1 cm, (2) a mass or masslike consolidation greater than 1 cm with or without cavitations or bronchograms, (3) alveolar or interstitial infiltrates, (4) masses of pleural origin, (5) peribronchial or perivascular thickening with or without atelectasis, (6) pleural effusions, and (7) hilar or mediastinal lymphadenopathy. The most common CT finding was a mass or masslike consolidation larger than 1 cm, seen in 21 (68%) of the 31 patients. The second most common finding was nodules less than 1 cm (19 patients). Sixty-eight percent of patients had three or more of the CT abnormalities. Lymphoma involving the lung parenchyma causes a variety of CT findings, the most common being a mass or masslike consolidation. Two-thirds of patients have more than one type of CT finding simultaneously.     

Hypersensitivity pneumonitis: spectrum of high-resolution CT and pathologic findings

OBJECTIVE: The purpose of this article is to illustrate the spectrum of pathologic and high-resolution CT features of hypersensitivity pneumonitis (HP). CONCLUSION: High-resolution CT plays an important role in the diagnosis of HP. A confident diagnosis of subacute HP is based on the presence of ground-glass opacities, poorly defined centrilobular nodules, and mosaic attenuation on inspiratory images and of air trapping on expiratory CT images. Chronic HP is characterized on high-resolution CT by the presence of reticulation due to fibrosis superimposed on findings of subacute HP. Histologically, subacute HP is characterized by the presence of cellular bronchiolitis, noncaseating granulomas, and bronchiolocentric lymphocytic interstitial pneumonitis. Areas of organizing pneumonia also may be seen. The high-resolution CT and pathologic features of chronic HP frequently overlap with those of nonspecific interstitial pneumonia and usual interstitial pneumonia. Awareness of the various manifestations of HP is important for early diagnosis and management.     

Pulmonary disease in liver transplant recipients. Spectrum of CT features

PURPOSE: To determine the features of pulmonary disease in liver transplant recipients by CT. MATERIAL AND METHODS: Of 792 patients, 102 were referred to thoracic CT 3-2093 days after the transplantation procedure (median 107 days). All CT studies were retrospectively analyzed and correlated with clinical, microbiological, serological and histopathological findings. RESULTS: Eighty-eight of 102 patients (86%) had an abnormal CT. In 25 patients (25%), an elevated right hemidiaphragm, basal atelectasis and small effusions were the only abnormalities. Fourty-one patients (40%) displayed an infiltrate and 13 (13%) a mass lesion. Evidence of cytomegalovirus (CMV) infection was found in 20 patients. CMV pneumonia was suggested by an interstitial pattern of pneumonia on CT (n=13). Pneumocystis carinii pneumonia was highlighted by peribronchovascular infiltrates (n=5/8), bacterial pneumonia (n=24) including legionellosis (n= 13) by bilateral effusions (n=14) and lobar consolidation (n= 13). In 7/41 patients (17%) with both clinically apparent pulmonary disease and CT signs of pneumonia, no pathogen could be detected. Neoplastic disease was mostly due to tumor recurrence (n=6). CONCLUSION: Thoracic CT of liver transplant recipients aids in detecting and classifying both infectious and neoplastic complications.     

Computerized tomography in the study of thoracic-pulmonary complications after liver transplantation

PURPOSE: To review the role of Computed Tomography (CT) in thoracic complications following orthotopic liver transplantation (OLT). MATERIAL AND METHODS: In a post-OLT population of 567 patients transplanted in our institution, 100 patients (17.6%) were examined with chest CT. We reviewed data relative to the total number of examinations, clinical and/or radiographic indications, the CT technique--i.e., conventional (with(out) intravenous, i.v., contrast material) or high-resolution (HRCT). We also reviewed the radiologic patterns and their correlation with the other clinical, bronchoscopic and/or laboratory results. RESULTS: Of 152 chest CT examinations, 45 (29.6%) were performed because of clinical indications, 31 (20.4%) because of a radiographic abnormality, 64 (42.1%) because of clinical and radiographic indications, while in 12 cases (7.9%) the reasons were unknown; 133/152 (87.5%) examinations had been performed with conventional CT scanning (100 with i.v. contrast agent and 33 without) and 19/152 (12.5%) with HRCT. Twenty of 152 (13.2%) examinations, in 16 patients, were normal; in the other 84 patients, 132/152 (86.8%) CT/HRCT studies showed 247 pathological findings (99 pleural effusions, 3 pericardial effusions, 62 cases of atelectasis, 1 pulmonary calcification, 70 suspected inflammatory parenchymal consolidations, 64 of them alveolar and 6 interstitial, 4 cases of interstitial edema and finally 8 neoplastic infiltrates). DISCUSSION: Correlated with clinical data, CT findings are very useful in detailing clinical-radiographic screening findings, despite the limitations in typifying pleural effusions, in differentiating atelectases from inflammatory parenchymal consolidations and in assessing pneumonia etiology. Also, despite its high sensitivity (94.1%) and specificity (92.8%), CT was not accurate enough in the differential diagnosis of pneumonia. History data were necessary to characterize the histology of neoplastic infiltrates. CONCLUSIONS: Chest CT has relatively uncommon, and sometimes only clinical, indications in post-OLT patients. The technique is chosen based on clinical-radiographic findings. CT proved useful in showing negative cases and in detailing clinical and radiographic findings but must be integrated with clinical findings to define inflammatory and neoplastic conditions.     

Organizing pneumonia: prognostic implication of high-resolution computed tomography features

PURPOSE: Most patients with biopsy-proven organizing pneumonia (OP) show complete resolution of radiographic lesions with treatment, but some patients do not respond to treatment and progress to pulmonary fibrosis. The authors investigated the prognostic implication of high-resolution computed tomography (CT) features in this condition. METHOD: We reviewed the high-resolution CT findings of 26 patients diagnosed with OP by histopathology, who had radiographic follow-up for a median of 44 weeks after treatment. We scored the presence and extent of each pretreatment high-resolution CT finding (ground-glass opacity, consolidation, nodules, reticular opacity, and honeycombing). The predominant pattern and distribution of the lesions were recorded. Follow-up radiographs were used to determine whether the parenchymal abnormalities had regressed or progressed in response to treatment. RESULTS: Of the 26 patients, 9 had persistent or progressive parenchymal abnormalities at follow-up (group 1), whereas 17 had complete or partial resolution of abnormalities (group 2). Consolidation was present on the initial CT scan in 14 (82%) of the 17 patients in group 2, but in only 2 of the 9 patients in group 1 (P = 0.009). None of the 6 patients who had reticular abnormality as the predominant pattern on initial CT showed complete resolution on follow-up imaging (P = 0.02). CONCLUSION: In patients with OP, the CT finding of consolidation is associated with partial or complete resolution, whereas reticular opacity is associated with persistent or progressive disease.     

Pulmonary infections following bone marrow transplantation: high-resolution CT findings in 35 paediatric patients

PURPOSE: The purpose of this study was to assess the high-resolution CT findings of paediatric patients who had pulmonary infections following bone marrow transplantation (BMT), and to evaluate the differential diagnosis through high-resolution CT of the various pathogens responsible for pulmonary infections after BMT. PATIENTS AND METHODS: The study included 35 consecutive patients who had documented pulmonary infection, high-resolution CT of the chest performed within 24h of the beginning of symptoms, and proven diagnosis within 1 week of the onset of symptoms. The pulmonary infections were due to viruses (n=16), bacteria (n=9), fungi (n=9), and protozoa (n=1). Two radiologists analyzed the CT scans and reached final decisions regarding the findings by consensus. RESULTS: Four patients with confirmed pneumonia had normal high-resolution CT scans. Regarding the viral infections, the most frequent features were areas of ground-glass attenuation (43.7%) and small centrilobular nodules (31.2%). Airspace consolidation (88.9%), small centrilobular nodules (22.2%) and ground-glass attenuation (22.2%) were the most frequent findings in patients with bacterial pneumonia following BMT. Large nodules were seen in 66.7% of the patients with fungal pneumonia, and in only one case of virus infection. The "halo sign" (n=5) was seen only in patients with fungal pneumonia. CONCLUSION: In conclusion, the main causes of pulmonary infection in paediatric patients following BMT share similar high-resolution CT findings. Large nodules and "halo sign" are more common in patients with fungal infections.     

Thoracic CT findings of adult T-cell leukemia or lymphoma

OBJECTIVE: The aim of this study was to assess pulmonary CT findings in patients with adult T-cell leukemia or lymphoma. MATERIALS AND METHODS: We retrospectively reviewed CT scans of the lung in 87 patients with adult T-cell leukemia or lymphoma who had undergone chest CT between January 1996 and March 2002 at two institutions. The CT scans were interpreted by two chest radiologists working in consensus. Parenchymal abnormalities (ground-glass attenuation, consolidation, nodules, thickening of bronchovascular bundles, interlobular septal thickening, honeycombing, crazy-paving appearance, and bronchiectasis) were evaluated, as were enlarged lymph nodes, pleural effusion, and pleural thickening. In 46 patients who underwent surgical biopsy or autopsy, CT-pathologic correlation was performed with the actual specimens by a pathologist and two chest radiologists. RESULTS: On the CT scans, abnormal findings were seen in 60 patients (69.0%). CT findings consisted of ground-glass attenuation (n = 37), centrilobular nodules (n = 25), thickening of bronchovascular bundles (n = 22), and consolidation (n = 13). These abnormalities were predominantly seen in the peripheral lung parenchyma (n = 26). Pathologically, these findings corresponded with atypical lymphocyte infiltration along the interstitium and the alveolar spaces. Pleural effusion and enlarged lymph nodes were found in 22 and 27 patients, respectively. CONCLUSION: CT findings in patients with adult T-cell leukemia or lymphoma consisted mainly of ground-glass attenuation, centrilobular nodules, and thickening of the bronchovascular bundles in the peripheral lung. These findings, although nonspecific, are considered suggestive of thoracic involvement in patients with adult T-cell leukemia or lymphoma.     

Chronic cystic lung disease: diagnostic accuracy of high-resolution CT in 92 patients

OBJECTIVE: The objective of this study was to determine whether the various chronic cystic lung diseases can be differentiated on the basis of the pattern and distribution of abnormalities on high-resolution CT. MATERIALS AND METHODS: High-resolution CT scans in 92 patients with chronic cystic lung diseases (18 with pulmonary Langerhans cell histiocytosis, 18 with pulmonary lymphangioleiomyomatosis, 17 with usual interstitial pneumonia, 16 with lymphocytic interstitial pneumonia, 15 with emphysema, and eight with desquamative interstitial pneumonia or respiratory bronchiolitis interstitial lung disease) were retrospectively assessed by two independent observers without knowledge of the clinical or pathologic data. The observers recorded the abnormalities, the most likely diagnosis, and the degree of confidence in that diagnosis. RESULTS: The two observers made a correct first-choice diagnosis in 148 (80%) of 184 interpretations. The correct diagnosis was made in 100% of interpretations of usual interstitial pneumonia, 81% of desquamative interstitial pneumonia or respiratory bronchiolitis interstitial lung disease, 81% of lymphocytic interstitial pneumonia, 77% of emphysema, 72% of lymphangioleiomyomatosis, and 72% of Langerhans cell histiocytosis. The two observers made a diagnosis with a high degree of confidence in 105 (57%) of 184 interpretations. The confident diagnosis was correct in 98 (93%) of 105 interpretations. CONCLUSION: Although various chronic cystic lung diseases often have a characteristic appearance that allows their distinction on high-resolution CT, considerable overlap exists among the CT findings. Therefore, lung biopsy is often required for a definitive diagnosis.     

Respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, and desquamative interstitial pneumonia: different entities or part of the spectrum of the same disease process?

OBJECTIVE: Our objective was to assess high-resolution CT findings of respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, and desquamative interstitial pneumonia and to determine whether these three entities could be reliably differentiated by radiologic criteria. MATERIALS AND METHODS: CT scans (1- to 3-mm collimation) were reviewed in 40 patients with pathologically proven respiratory bronchiolitis (n = 16), respiratory bronchiolitis-associated interstitial lung disease (n = 8), or desquamative interstitial pneumonia (n = 16). All patients with respiratory bronchiolitis and respiratory bronchiolitis-associated interstitial lung disease were cigarette smokers, and 85% of the patients with desquamative interstitial pneumonia had a history of smoking. CT scans were independently reviewed by two radiologists who assessed the pattern and distribution of abnormalities. RESULTS: The predominant abnormalities in respiratory bronchiolitis were centrilobular nodules (12 [75%] of 16 patients) and ground-glass attenuation (six [38%] of 16). No single abnormality predominated in the respiratory bronchiolitis-associated interstitial lung disease group; findings included ground-glass attenuation (four [50%] of eight), centrilobular nodules (three [38%] of eight), and mild fibrosis (two [25%] of eight). All patients with desquamative interstitial pneumonia showed ground-glass attenuation, and 10 (63%) of the 16 showed evidence of fibrosis. CONCLUSION: The significant overlap between the CT findings of respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, and desquamative interstitial pneumonia is consistent with the concept that they represent different degrees of severity of small airway and parenchymal reaction to cigarette smoke.     

Pathologic subgroups of nonspecific interstitial pneumonia: differential diagnosis from other idiopathic interstitial pneumonias on high-resolution computed tomography

OBJECTIVE: To determine whether the subtypes of nonspecific interstitial pneumonia (NSIP) could be differentiated from other idiopathic interstitial pneumonias (IIPs) on the basis of findings on high-resolution computed tomography (CT). METHODS: Two observers evaluated the high-resolution CT findings in 90 patients with IIPs. The patients included 36 with NSIP, 11 with usual interstitial pneumonia (UIP), 8 with cryptogenic organizing pneumonia (COP), 10 with acute interstitial pneumonia (AIP), 14 with desquamative interstitial pneumonia (DIP) or respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), and 11 with lymphoid interstitial pneumonia (LIP). The NSIP cases were subdivided into group 1 NSIP (n = 6), group 2 NSIP (n = 15), and group 3 NSIP (n = 15). RESULTS: Observers made a correct diagnosis with a high level of confidence in 65% of NSIP cases, 91% of UIP cases, 44% of COP cases, 40% of AIP cases, 32% of DIP or RB-ILD cases, and 82% of LIP cases. Group 1 NSIP was misdiagnosed as AIP, DIP or RB-ILD, and LIP in 8.3% of patients, respectively. Group 2 NSIP was misdiagnosed as COP in 10% of patients, LIP in 6.7%, AIP in 3.3%, and DIP or RB-ILD in 3.3%. Group 3 NSIP was misdiagnosed as UIP in 6.7% of patients, COP in 6.7%, and DIP or RB-ILD in 3.3%. CONCLUSIONS: In most patients, NSIP can be distinguished from other IIPs based on the findings on high-resolution CT. Only a small percentage of patients with predominantly fibrotic NSIP (group 3 NSIP) show overlap with the high-resolution CT findings of UIP.     

Pulmonary infections after bone marrow transplantation: high-resolution CT findings in 111 patients

OBJECTIVE: The purpose of this study was to review the high-resolution CT findings in patients with pulmonary infection after bone marrow transplantation and to determine distinguishing features among the various types of infection. MATERIALS AND METHODS: This study included 111 consecutive bone marrow transplant recipients who had documented pulmonary infection, high-resolution CT of the chest performed within 24 hr of the beginning of symptoms, and proven diagnosis within 1 week of the onset of symptoms. Two radiologists analyzed the CT scans and reached final decisions regarding the findings by consensus. Statistical analysis was performed using the Fisher's exact test and multivariate analysis; a p value of less than 0.05 was considered statistically significant. RESULTS: The pulmonary infections were due to viruses (n = 57), bacteria (n = 26), fungi (n = 21), and protozoa (n = 1). Six patients had more than one organism responsible for the infection. Nodules that were 1 cm or more in diameter were seen in 13 (62%) of 21 patients with fungal pneumonia, five (19%) of 26 patients with bacterial pneumonia (p = 0.0059), three (10%) of 30 with respiratory syncytial virus (RSV) pneumonia (p = 0.0001), and three (14%) of 22 with cytomegalovirus pneumonia (p = 0.0016). The halo sign was present in 10 of 21 patients with fungal pneumonia, two of 26 with bacterial pneumonia (p = 0.0026), three of 30 with RSV pneumonia (p = 0.0036), and one of 22 with cytomegalovirus pneumonia (p = 0.0015). There was no statistically significant difference in the prevalence of the other CT patterns including small nodules, ground-glass attenuation, and air-space consolidation among viral, bacterial, and fungal infections (all p > 0.05). CONCLUSION: The presence of large nodules and visualization of the halo sign are most suggestive of fungal infection. Other high-resolution CT patterns are not helpful in distinguishing among the various types of infection seen in bone marrow transplant recipients.