Differential CT Features between Malignant Mesothelioma and Pleural Metastasis from Lung Cancer or Extrathoracic Primary Tumor Mimicking Malignant Mesothelioma

PURPOSE: To evaluate the differential CT features found among malignant mesothelioma and pleural metastasis from lung cancer and from extrathoracic primary tumor which on CT mimic malignant mesothelioma. MATERIALS AND METHODS: Forty-four patients who on chest CT cans showed pleural thickening suggesting malignant pleural disease and in whom this condition was pathologically confirmed were included in this study. On the basis of their pathologically proven primary disease [malignant mesothelioma (n=14), pleural metastasis of lung cancer (n=18), extrathoracic primary tumor (n=12)]. they were divided into three groups. Cases of lung which on CT showed a primary lung nodule or endobronchial mass with pleural lesion, or manifested only pleural effusion, were excluded. The following eight CT features were retrospectively analyzed: 1) configuration of pleural lesion (type I, single or multiple separate nodules, type II, localized flat pleural thickening, type III, diffuse flat pleural thickening; type IV, type III with pleural nodules superimposed; type V, mass filling the hemithorax), 2) the presence of pleural effusion, 3) chest wall or rib invasion, 4) the involvement of a major fissure, 5) extrapleural fat proliferation, 6) calcified plaque, 7) metastatic lymph nodes, 8) metastatic lung nodules. RESULTS: In malignant mesothelioma, type IV (8/14) or II (4/14) pleural thickening was relatively frequent. Pleural metastasis of lung cancer favored type IV (8/18) or I (6/18) pleural thickening, while pleural metastasis from extrathoracic primary tumor showed a variable thickening configuration, except type V. Pleural metastasis from lung cancer and extrapleural primary tumor more frequently showed type I configuration than did malignant mesothelioma, and there were significant differences among the three groups. Fissural involvement, on the other hand, was significantly more frequent in malignant mesothelioma than in pleural metastasis from lung cancer or extrapleural primary tumor . Metastatic lymph nodes and metastatic lung nodules were significantly more frequent in pleural metastasis from lung cancer and extrapleural primary tumor than in malignant mesothelioma. CONCLUSION: Malignant mesothelioma showed significantly frequent fissural involvement and the frequency with which pleural metastasis from both lung cancer and extrathoracic primary tumor showed type I pleural lesion, metastatic lymph nodes or metastatic lung nodules, was significantly frequent. Even though no CT features for differentiating between pleural metastasis from lung cancer and from extrathoracic primary tumor were found, the CT features stated above would help differentiate malignant mesothelioma from the other two groups.

The Frequency and the Degree of Fusion of the Lung on High-Resolution CT

PURPOSE: To evaluate the frequency and degree of fusion of the lung, as seen on high-resolution CT(HRCT). MATERIALS AND METHODS: In 210 patients high-resolution CT scans from the apex to the diaphragm were obtained at 1mm collimation and 7mm interval. We retrospectively analysed the frequency and degree of fusion of the lung bordering each interlobar fissure. Fusion of the lung was defined when fissure appeared without complete lobar separation. The degree of lung fusion was classified as mild (less than 1/3 of the fissure), moderate (greater than 1/3 and less than 2/3 of fissure), or severe (greater than 2/3 of the fissure). RESULT: In 90 of 210 patients, all fissures were identified. In 73 of these 90 (81.1%), lung fusion was noted, the most frequent site of this being between the right upper and right middle lobe (53.3%). The least frequent site was between the upper portion of the left upper and left lower lobe (32.2%). Am mild degree of fusion was most frequently found between the right middle and right lower lobe (83.9%), while a severe degree was most frequentl between the right middle and right upper lobe (50.0%), followed by the lingular division and the left lower lobe (41.9% ). CONCLUSION: HRCT can be used to were able to evaluate the frequency and degree of interlobar lung fusion.

Squamous Cell Carcinoma Associated with Chronic Empyema Caused by Metallic Fo reign Body: A Case Report

Malignant neoplasm associated with chronic empyema is rare. Most squamous cell carcinomas of the pleura may occur in association with chronic persistent empyema, with or without pleurocutaneous fistula. We report a case of squamous cell carcinoma associated with chronic empyema caused by a metallic foreign body.

Peripheral Bronchopleural Fistula: CT Evaluation in 22 patients

PURPOSE: To determine the usefulness of CT for the evaluation of peripheral bronchopleural fistulas. MATERIALS AND METHODS: CT scans of 22 patients with persistent air leak, as seen on serial chest PA, and aclinical history, were retrospectively evaluated. We determined the visibility of direct communication between thelung and pleural space, and the frequeucy and location of this, and if direct communications were not visualizedthe probable cause. RESULTS: A bronchopleural fistula(n=13) or its probable cause(n=6) was visualized in 19patients(86%). Direct communications between the lung and pleural space were seen in 13 patients(59%); there weresix cases of tuberculous empyema, three of tuberculosis, two of necrotizing empyema, one of trauma, and one ofpostobstructive pneumonitis. In six patients, bronchiectatic change in peripheral lung adjacent to the pleuralcavity was noted, and although this was seen as a probable cause of bronchopleural fistual, direct communicationwas invisible. Bronchopleural fistula or its probable cause was multiple in 18 of 19 patients, involving the upperand lower lobe in eight, the upper in nine, and the lower in two. CONCLUSIONS: CT is useful for evaluating thepresence of bronchopleural fistula, and its frequency and location, and in patients in whom the fistula is notdirectly visualized, the cause of this.

CT Findings of Pleural Dissemination from Lung Cancer

PURPOSE: The purpose of our study was to identify the CT findings that help detect pleural dissemination from lung cancer and to evaluate the usefulness of selected diagnostic criteria. MATERIALS AND METHODS: After a computerized database search of 606 patients who had undergone thoracotomy for primary lung cancer, 23 patients were identified as h aving surgically documented pleural dissemination. From the same database, 50 patients without pleural dissemination during thoracotomy were randomly selected as controls. Preoperative CT scans and medical records were rev i ewed retrospectively, and findings were compared between the two groups. RESULT: One or more of three types of pleural thickening (plaque-like, nodular, and fissural) were identified on CT as the most discriminating finding (sensitivity, 74 % ; specificity, 60 %; p = 0.007). The following findings were also significantly discriminating (p<0.05): contiguity of primary tumor with the pleural surface as seen on CT; adenocarcinoma in cell type; and a peripheral tumor defined as one in which bronchoscopy revealed no endobronchial lesion. The use of combinations of these findings in addition to pleural thickening rendered diagnostic criteria more specific at the cost of the sensitivity. CONCLUSION: During preoperative CT evaluation of lung cancer, the recognition of subtle pleural thickening helps detect pleural dissemination. The likelihood that subtle pleural thickening represents pleural dissemination is increased when a primary tumor is contiguous with the pleural surface, is an adenocarcinoma, or is peripherally located.

CT Findings of Pleural Dissemination in Primary Lung Cancer

PURPOSE: To evaluate the CT findings of pleural dissemination in primary lung cancer and the limitations of CT scanning in detecting pleural dissemination in primary lung cancer. MATERIALS AND METHODS: Primary lung cancer with pleural dissemination was diagnosed in 68 patients and confirmed by pleural biopsy, cytology and surgery, and these cases were the subject of this study. Adenocarcinoma accounted for 49, squamous cell carcinoma for 13 and small cell carcinoma for six. Eight CT features, namely the amount of pleural effusion, the contour, extent andlocation of pleural thickening, the shortest distance between pleura and mass, pleural calcification, pleural tailsign and the extent of extrapleural fat proliferation, were evaluated. RESULTS: Pleural effusion was noted in 51 of 68 patients(75%), though in most cases(70%), the amount of this was small. Among 42 patients(62%) in whom thickened pleura, were noted, pleural thickening was thin and irregular in 22(52%), thick and irregular in 16(38%), and thin and regular in 4(10%). The extent of pleural thickening was multifocal in 22 patients(52%),diffuse in 16(38%), and circumferential and single in two(5%). Pleural thickening was more frequently noted at theposterior than the anterior pleura. Pleural abutting was seen in 53 patients(78%). In ten patients(15%), chest CTscans revealed no perceptible pleural abnormalities. CONCLUSION: If in primary lung cancer, the primary lung masscontacts the pleura, and if pleural thickening, even when slight, shows marginal irregularity, pleuraldissemination should be considered. Although CT scanning is very useful for the detection of pleural disseminationin primary lung cancer, about 15% of patients showed no perceptible pleural abnormalities. Other diagnosticmodalities such as thoracoscopy are mandatory for the correct diagnosis of pleural dissemination in primary lung cancer.

Differential Diagnosis of Tuberculous Pleural Effusion and Malignant Pleural Effusion: CT Accuracy and Findings

PURPOSE: To evaluate the diagnostic accuracy of CT in the differential diagnosis of tuberculous and malignant pleural effusion whether or not lung lesions are present, and to investigate the CT findings used for this differential diagnosis. MATERIALS AND METHODS: This study involved 30 patients with tuberculous pleural effusion (mean age, 44.6 years; M:F=19:11) and 20 with malignant pleural effusion (mean age, 57.2 years; M:F=10:10). All 50 patients underwent enhanced CT chest scans, and the respective conditions were pathologically confirmed. Two radiologists unaware of the pathologic results and distribution of patients reviewed these scans retrospectively and independently. They recorded the presence or absence of helpful lung lesions, CT findings of pleural effusions, their diagnoses, and the degree of confidence of their diagnoses. RESULTS: Among the total of 100 answeres, helpful long lesions were found in 57 cases. Fifty-three of 57 diagnoses (93%) were correct and 26 cases (46%) were diagnosed with a high degree of confidence. Thirty-two of 43 cases (74%) without helpful lung lesions were correct and 11(26%) were diagnosed with a high degree of confidence. All diagnoses made with a high degree of confidence were correct, even in cases without helpful lung lesions. Frequent CT findings in tuberculous pleural effusion included diffuse pleural thickening, enhancement of pleura, deposition of extrapleural fat, and pleural calcification; in malignant pleural effusion, nodular pleural thickening, pleural thickening over 1cm and associated lymphadenopathy were frequent. Mediastinal and circumferential pleural, as well as fissural involvement, were seen in both effusions; there were no statistical differences. CONCLUSION: In most cases, CT provided correct differential diagnosis between tuberculous and malignant pleural effusion. It can help determine the nature of associated lung and pleural lesions, and specific findings of the latter, and can accurately differentiate tuberculous and malignant pleural effusion.

Plueral Lipoma: A Case Report

Lipoma is a common benign neoplasm, but lipoma arising from the pleura is rare; it is composed of mature adipose tissue and occasionally fibrous stroma. The tumor shows characteristic radiographic and CT features of pleural mass, and the lesion is homogeneous and low density, with CT numbers indicating fat. The mass was removed by surgery and confirmed as a lipoma originating from the parietal pleura.

CT Findings of Diffuse Pleural Diseases: Differentiation of Malignant Diseases from Tuberculosis

PURPOSE: To evaluate whether or not previously known CT criteria for differentiating malignant and benign pleural diseases are useful in the differentiation of diffuse malignant pleural diseases and tuberculosis. MATERIALS AND METHODS: We retrospectively analyzed CT scans of 42 patients comprising 20 cases of malignant pleural diseases and 22 cases of tuberculous pleural diseases, according to previously known CT criteria for differentiating malignant and benign pleural diseases. RESULTS: The most common shape of pleural effusion was crescentic in malignant pleural diseases and loculated in tuberculosis. The aggressive nature of pleural effusion, pleural rind, and pleura thickenign was 1.5 times more frequently observed in malignant pleural diseases than in tuberculosis. Smooth thickening or smooth nodular pleural thickening and extrapleural deposition of fat were 1.5 times more frequently found in tuberculous than in malignant pleural diseases. Interruption of pleural thickening was found twice as frequently in malignant pleural diseases as in tuberculosis. Decreased lung volume was found twice as frequently in tuberculous as in malignant pleural diseases. Anatomical mediastinal pleural involvement was three times, and irregular nodular pleural thickening nine times more frequent in malignant pleural diseases than in tuberculosis. The sensitivity and specificity of CT findings above 70%, and thus suggesting malignant pleural diseases, were as follows: 1) aggressive nature of pleural fluid collection extending to the azygoesophageal recess or tongue of the lung (51.5%, 75%); 2) involvement of anatomical mediastinal pleura (69.2%,73.7%); 3) irregular nodular pleural thickening (87.5%, 69%). CONCLUSION: Although there in overlap between previously known CT criteria for the differentiation of benign and malignant pleural diseases, the aggressive nature of pleural fluid collection extending to the azygoesophageal recess or tongue of the lung, the involvement of anatomical mediastinal pleura and irregular nodular pleural thickening may suggest malignant pleural diseases.

Can Anterior Junction Line be Used to Distinguish Right Middle from Right Upper Lobe on CT Scan?

PURPOSE: To evalvate the usefulness on a CT chest scan, of the anterior junction line as an anatomical landmark to distinguish the right middle and the right upper lobe MATERIALS AND METHODS: We found that the anterior junction line has a constant anatomical relationship with the right upper and middle lobe, and with this in mind, analysed connvcntional CT films of 86 patients with normal lung (group A) and 30 with architectural distortion (group B). On a series of slices, we compared the location of slice 1 with that of slice 2 (slice 1: the slice which includes the lowest portion of the anterior junction line, slice 2: the initial slice, in which the right middle lobe occupies the whole of the lung anterior to the right major fissure). RESULTS: In group A (n=86), the right upper lobe, as seen in the anteromedial zone of slice 1, was present in 83 cases (96.5%). The right upper lobe on slice 1 was absent in two cases (2.3%) in which a minor fissure was almost completely abent. In group B (n=30), the right upper lobe on slice 1 was absent in 19 cases (63.3%). CONCLUSION: We suggest that on a CT chest scan, the anterior junction line can be used as an anatomical landmark in the differentiation of the right middle from the right upper lobe, and as an indicator of the presence of architectural distortion.

Malignant and Benign Diffuse Pleural Disease: Utility of FDG PET in Differential Diagnosis and Comparison with CT

PURPOSE: To assess the utility of 2-[18F] fluoro-2-deoxy-D-glucose (FDG) PET in differentiating malignant and benign diffuse pleural disease, and to compare it with CT. MATERIALS AND METHODS: Both FDG PET and CT scans were performed in 20 consecutive patients with diffuse pleural disease (13 malignant and seven benign cases). In FDG PET, peak standardized uptake value (SUV) as well as visual assessment of abnormally increased uptake in the pleura was evaluated. The results were compared with CT findings. RESULTS: With only visual assessment of PET images, sensitivity, specificity, and accuracy for malignancy were 92%, 43%, and 75%, respectively. With peak SUV of 4.8 or more, the corresponding figures were 100%, 57%, and 85%, respectively, and on CT interpretation, were100%, 57%, and 85%, respectively. Tuberculous empyema simulated malignant pleural disease both on FDG PET (3/6 patients with peak SUV more than 4.8) and CT (3/6 patients). CONCLUSION: For the differentiation of malignant and benign diffuse pleural disease, FDG PET and CT are equally accurate. Combined visual and quantitative assessments of PET images enhance discriminatory ability. Tuberculous empyema simulates malignant pleural disease both on FDG PET and CT.

Therapeutic Effectiveness of Intracavitary Urokinase in the Management of Stage II Empyema Patients

PURPOSE: The author tried to compare the therapeutic effectiveness of urokinase instillation via PCD catheter with other conventional therapeutic modalities such as thoracentesis, closed thoracostomy and percutaneou scatheter drainage in the management of patients with early and late stage II empyema. MATERIALS AND METHODS: Twenty seven of early and 19 of late stage II empyema patients were reviewed. We compared each results of the treatments including the average hospitalization day, success rate, and interval between first procedure and 75% improvement on simple chest film. RESULTS: The average hospitalization day and improvement interval of stage II empyema patients, who were treated with urokinase instillation via PCD catheter, were shortest of all. In earlystage II, they were 11.8 and 8.5 days, and 16.7 and 9.4 days in late stage II patients. In each patient with early and late stage II empyema, they were 17.2, 11.5 days and 24.3, 16.2 days with thoracentesis, 48.0, 32.3 days and 37.7, 24.0 days with closed thoracostomy, 35.2, 17.2 days and 34.8, 20.0 days with percutaneous cathter drainage. All patients treated with intracavitary urokinase showed complete drainage of empyema. CONCLUSION: Intracavitary urokinase facilitates percutaneous catheter drainage of empyema, with resultant reduction of hospitalization days. Also this method has high success rate.

Normal Apical Pleural Tenting: CT Findings

PURPOSE: To define the anatomy of apical pleural tenting commonly seen in computed tomography(CT) of the upper posterior thorax. MATERIALS & METHODS: Chest CTs of 393 patients with no pleural disease clinically and radiographically were analyzed. GE-9800 Quick and Toshiba-900S were used, employing the usual contrast enhanced CTtechnique. CT findings of focal pleural tenting on the inner side of the upper posterior thorax(apical pleural tenting) were evalvated and analysed in terms of location and shape. The CT findings were compared with the gross findings of the inner aspect of the posterior cadaveric thorax. RESULTS: Apical pleural tenting was formed by the upper border of the subcostal muscle. It's incidence was 44%(n=171), with bilaterality in 29%(n=49), and unilaterality in 71% of cases(n=122). This tenting was most frequently found between the third rib and the fourth intercostal space(81%), and seen in the outer third(42%) or central third(41%) part of the posterior costalpleura. In fifteen cases(7%), it was directed obliquely and had changed its location from the inner to the centralor the central to the outer part. The shapes of the tenting were classified as follows : type 1(convex innerborder with sharp apex, 62%) ; type 2(convex inner border with broad apex, 23%) ; type 3(undulated contour ofapex, 13%) ; and type 4(two-spike apices, 1%). CONCLUSION: Apical pleura tenting is a normal CT finding probably demonstrated by the upper border of the subcostal muscle. Misdiagnosis of pleural disease can be avoided by recognition of the location and type of this tenting.

Enhanced CT in the Patients with Pleural Effusion: Differential Findings between Exudates and Transudates

PURPOSE: To evaluate the differential findings of CT in the differention of pleural exudates and transudates. MATERIALS AND METHODS: One hundred and thirteen consecutive patients (113 effusions) underwent enhanced thoracic CT ; the scans were evaluated for the presence or absence and appearance of enhancing parietal pleural thickening and extrapleural fat thickening. Thoracentesis was performed to measure pleural and serum total protein andlactate dehydrogenase(LDH) values. Effusions were classified as exudates by using Light's criteria. RESULTS: Eighty-eight effusions were exudates and 25 were transudates. Eighty-three of the 88 exudates (93%) were associated with enhanced parietal pleural thickening ; seventy of the 88 (80%) were associated with extrapleural fat thickening. Four of the 25 transudates were associated with parietal pleural thickening and extrapleural fat thickening, both of which were the most important factors in differentiating beteen pleural exudates and transudates(p<0.05). CONCLUSION: Parietal pleural thickening and extrapleural fat thickening on contrast-enhanced CT almost always in dicate the presence of pleural exudates.

Benign Mass-like Lesions Associated with Chronic Tuberculous Empyema: CT Findings in 9 Patients

PURPOSE: To present CT findings of benign mass-like nodular lesions associated with chronic tuberculousempyema. MATERIALS AND METHODS: We retrospectively reviewed the CT scans of nine patients with mass-like lesions associated with chronic tuberculous empyema, which were pathologically (operation=4, US-guided biopsy=3) or clinically (n=2) confirmed as benign lesions. Shape, number, size, presence of calcification and enhancement pattern of mass-like lesions were assessed. RESULTS: In all patients, chest CT showed unilateral calcified pleural thickening, with mass-like nodular lesions. Fluid within the pleural cavity was observed in eight patients. CT findings of mass-like lesions were multiple and nodular (n=9). Calcification was demonstrated within the lesions in four patients. In each case, the size of the largest nodules was 1-3cm in diameter. In contrast, CTshowed mild (n=6) to moderate (n=2) enhancement compared with adjacent muscles. The pathologic results ofmass-like lesions were chronic inflammation (n=3) and necrosis (n=4). CONCLUSION: Benign mass-like lesions associated with chronic tuberculous empyema appeared as multiple nodules varying in size from 1 to 3cm in diamter, with slight enhancement.