Pleural effusions associated with acute pancreatitis: Incidence and appearance based on computed tomography

Recognition of pleural effusions in acute pancreatitis is important since it carries prognostic implications. This study evaluates the incidence and characteristics of pleural effusions on computed tomography (CT) of patients with mainly an alcohol ingestion etiology of acute pancreatitis. A review of medical records and abdominal CT scans in 50 patients with clinical and laboratory evidence of acute pancreatitis was carried out. All patients were referred for abdominal CT scanning based on an initial clinical presentation consistent with acute pancreatitis and had confirmatory elevation of the corresponding serum enzyme levels. The presence, laterality, and size of any pleural effusions were recorded from the initial sections through the lung bases.Based on a review of medical records, 36 patients (72%) had an alcohol-related etiology of acute pancreatitis.Overall, 10 patients (20%) with acute pancreatitis had pleural effusions on abdominal CT imaging. Five of the effusions were bilateral, three were unilateral right sided, and two were unilateral left sided. Nine of the effusions were small (<1 cm in maximal height) or medium (1–2 cm) in size.Small and medium-sized pleural effusions are not uncommon in acute pancreatitis. The higher incidence in this study compared to that in earlier reports likely represents the increased sensitivity of cross-sectional imaging for small amounts of pleural fluid. The absence of left-sided effusion predominance in our study group is contrary to much of the earlier literature and may reflect demographic factors, such as etiology and previous history of pancreatitis, although statistical variability must also be considered.     

Complications of pneumoconiosis: Radiologic overview

A wide spectrum of pulmonary complications occurs in patients with pneumoconiosis. Those complications include chronic obstructive pulmonary disease, hemoptysis, pneumothorax, pleural disease, tuberculosis, autoimmune disease, anthracofibrosis, chronic interstitial pneumonia, and malignancy. Generally, imaging workup starts with plain chest radiography. However, sometimes, plain radiography has limited role in the diagnosis of pulmonary complications of pneumoconiosis because of overlapping pneumoconiotic infiltration. Computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI) are potentially helpful for the detection of pulmonary complications in patients with pneumoconiosis. CT, with its excellent contrast resolution, is more sensitive and specific method than plain radiograph in the evaluation of pulmonary abnormalities. CT is useful in detecting lung parenchymal abnormalities caused by infection, anthracofibrosis, and chronic interstitial pneumonia. Also, CT is valuable in distinguishing localized pneumothorax from bullae and aiding the identification of multiloculated effusions. US can be used in detection of complicated pleural effusions and guidance of the thoracentesis procedure. MRI is useful for differentiating between progressive massive fibrosis and lung cancer.     

Imaging of the pleura.

With the use of plain radiography, CT, sonography, and more recently MR imaging, radiology has played a pivotal role in the diagnosis and treatment of patients with pleural effusions. The expanding use of CT scanning in patients with pleural disease has enhanced not only our understanding of the factors that affect the distribution of pleural fluid within the thorax, but also our understanding of pathologic and pathophysiologic changes in patients with pleural disease. This paper reviews significant recent developments in this area.     

The CT appearance of pleural and extrapleural disease in lymphoma.

OBJECTIVE: Pleural effusions in patients with lymphoma that are assumed to be related to malignancy are attributed to either lymphatic obstruction by tumour with resultant decreased clearance of pleural fluid, or direct tumour involvement of the pleura. The purpose of our study was to determine how often pleural or extrapleural disease was detected by computed tomography (CT) of patients with pleural effusions and primary or recurrent lymphoma. METHODS AND MATERIALS: We reviewed CT examinations showing evidence of pleural effusion in 61 patients with a diagnosis of primary or recurrent lymphoma and no history of other systemic disorders, including infection. The study population consisted of patients with non-Hodgkin's lymphoma (n = 44) or Hodgkin's disease (n = 17); both primary disease (n = 11) and recurrent disease (n = 50) were represented. Each CT examination was evaluated for the presence of disease involving the visceral and parietal pleura and extrapleural space, mediastinal adenopathy, and pulmonary parenchymal disease. RESULTS: Fourteen patients (23%) (nine with non-Hodgkin's lymphoma and five with Hodgkin's disease) had parietal pleural disease (thickening or nodules). Eighteen patients (30%) (14 with non-Hodgkin's lymphoma, four with Hodgkin's disease) had tumour or enlarged lymph nodes in the extrapleural space. Forty-three patients (70%) had mediastinal lymphadenopathy. Patients who received intravenous contrast did not have evidence of visceral pleural abnormalities or underlying pulmonary parenchymal disease. CONCLUSION: Forty-one percent of the patients with lymphoma and pleural effusions had CT evidence of pleural and/or extrapleural disease. The majority of the patients with extrapleural disease had adjacent posterior mediastinal disease.     

Image-guided pleural biopsies: indications, technique, and results in 23 patients

Twenty-six pleural biopsies were performed on 23 patients over a 3-year period. Twenty-three biopsies were performed guided with ultrasound; one, with computed tomography; and two, with fluoroscopy. Indications for an image-guided pleural biopsy were (a) pleural masses or thickening that were either not seen on chest radiographs or seen only on one view and (b) small or loculated pleural effusions of unknown cause with no mass seen. If only pleural fluid was present, reverse bevel needles were used for biopsy (n = 15). If a discrete pleural mass or thickening was seen with cross-sectional imaging, standard (16-20 gauge) biopsy needles were used (n = 11). In the 23 patients, biopsy results were true positive in ten (nine with malignancy, one with tuberculous pleurisy), true negative in ten (confirmed either at subsequent thoracotomy or clinical follow-up), and false negative in three. Complications were few, with a significant pneumothorax occurring in two patients (8.7%). Image-guided biopsy of small pleural lesions and small pleural effusions can be performed by the radiologist who understands the special needles and techniques involved.     

Thoracic computed tomography in patients with suspected malignant pleural effusions

AIM: To assess the role of contrast-enhanced computed tomography (CT) prospectively in patients with suspected malignant pleural effusions.MATERIALS AND METHODS: Forty consecutive patients referred for the investigation of a suspected malignant pleural effusion had contrast-enhanced thoracic CT, thoracoscopy, thoraco-centesis and pleural biopsy, either percutaneously or at thoracoscopy. Final diagnoses were based on histopathological or cytological analysis (n = 30), autopsy findings (n = 3) or clinical follow-up (n = 7). The pleural surfaces were classified at contrast-enhanced CT as normal or abnormal and, if abnormal, as benign or malignant in appearance using previously established CT criteria for malignant pleural thickening by two observers unaware of the pathological diagnosis.RESULTS: Pleural effusions were malignant in 32 patients and benign in eight patients. Pleural surfaces assessed at CT showed features of malignancy in 27 out of 32 patients with a malignant effusion (sensitivity 84%, specificity 100%). Overall, CT appearances indicated the presence of malignancy in 28 of 32 (87%) patients. All eight patients with benign pleural disease were correctly diagnosed by CT.CONCLUSION: Contrast-enhanced CT is of value in patients with suspected malignant pleural effusions. The previously established criteria for malignant pleural thickening of nodularity, irregularity and pleural thickness >1 cm are reliable in the presence of a pleural effusion.     

Evaluation of CT findings for diagnosis of pleural effusions

Computed tomography studies are usually used to assess patients with pleural effusions, and radiologists should be aware of the significance of different CT findings for the diagnosis of the effusion. The purpose of this study was to evaluate CT findings for etiological diagnosis of pleural effusions. Contrast-enhanced CT of the chest of 211 patients with pleural effusion of definite diagnosis were evaluated. The CT images were evaluated for the presence and extent of pleural effusion, thickening or nodules, extrapleural fat and other changes in the mediastinum or lung. The CT scans were read by two independent observers and correlation between them was evaluated. Comparison of CT findings between benign and malignant effusions, between exudates and transudates, and between empyemas and the other parapneumonic effusions were carried out. Kappa values for most CT findings were > 0.85. Loculation, pleural thickening, pleural nodules, and extrapleural fat of increased density were only present in exudative effusions. Multiple pleural nodules and nodular pleural thickening were the only pleural findings limited to malignant pleural effusions. The signs were also more frequently seen in empyemas than in other parapneumonic effusions. Computed tomography findings can help to distinguish between transudates and exudates. Although there is some overlap between benign and malignant pleural effusions, pleural nodules and nodular pleural thickening were present almost exclusively in the latter. Although differences between CT findings of empyemas and the other parapneumonic effusions exist, there is no finding which can definitely differentiate between them. Received: 27 January 1999; Revised: 24 June 1999; Accepted: 24 August 1999     

Emergency ultrasound in trauma patients

US will be used more frequently in the future for the evaluation of traumatized patients. Previously,the main focus of the sonographic examination was for the detection of free fluid. Unstable patients with free fluid often can be triaged to the operation room without further imaging tests. In patients who are more stable or in whom US results are negative, CT is required. Based on recent studies, sonography has a sensitivity rate of approximately 40% in direct detection of solid organ injuries. In the future, however, with the use of contrast-enhanced agents, sonography may more reliably detect solid organ injuries. Within the chest, US has been shown to be helpful in detecting pleural effusions and may be useful in detecting pericardial effusions. US has been shown to be sensitive in detecting pneumothoraces in traumatized patients.     

Illustrative cases in pericardial effusion misdetection: Correlation of echocardiography and CT

Eight equivocal two-dimensional echocardiograms with concurrent CT scans were evaluated to identify potential pitfalls in pericardial effusion detection. By echocardiography, two pleural effusions were felt to be pericardial, two hemopericardiums were interpreted as normal myocardium, three loculated pericardial effusions were not seen or were misinterpreted as other mediastinal collections, and one epicardial lipoma was called a pericardial effusion. When the clinical suspicion for pericardial effusion does not correlate with echocardiographic findings, CT scanning may be the definitive arbiter of pericardial disease.     

Asbestos-related benign pleural disease

Benign pleural disease is the commonest manifestation of asbestos exposure encountered by radiologists. Benign pleural thickening can appear as circumscribed parietal pleural plaques or as more diffuse thickening of the visceral pleura. Benign-asbestos induced pleural effusions are a significant and under-recognized manifestation of asbestos exposure with important sequelae, such as diffuse pleural thickening which may be associated with functional impairment and for which compensation may be sought. This review concentrates on the strengths and weaknesses of chest radiography and computed tomography for the detection and characterization of benign asbestos-related pleural disease and the relevance of imaging abnormalities to compensation and functional impairment.Peacock, C. (2000). Clinical Radiology55, 422-432.     

Imaging manifestations of pleural tumors.

Although radiologic assessment of pleural tumors may be accomplished with several imaging modalities, the standard noninvasive techniques include chest radiography and computed tomography (CT). These examinations may be supplemented with magnetic resonance imaging and occasionally with ultrasound. Depending on the location, size, and underlying histologic features, pleural tumors may produce a spectrum of findings. CT is particularly useful in defining the location and extent of these masses. The authors present a review of basic pleural anatomy and imaging features of both benign and malignant pleural neoplasms. The pleural may be involved by one of several primary or metastatic tumors. Specific cell types are diffuse malignant mesothelioma (the most common plain radiographic findings are unilateral pleural effusion and pleural thickening), localized fibrous tumor (circumscribed, spherical or ovoid, noncalcified lesions arising in the pleural surface), metastatic disease (radiographic findings may mimic those of malignant mesothelioma), and uncommon neoplasms including thymoma and lymphoma. Among these various pleural tumors, metastatic disease represents the most common neoplasm.     

Atypical presentation of lymphangioleiomyomatosis as jugular vein thrombosis

Lymphangioleiomyomatosis is a rare disorder of unknown origin that almost exclusively affects women of childbearing age. It is characterised by proliferation of abnormal smooth muscle cells (lymphangioleiomyomatosis cells) in the pulmonary interstitium and along the thoracic and abdominal lymphatics. Lymphangioleiomyomatosis may be associated with tuberous sclerosis complex. The most common manifestations of lymphangioleiomyomatosis are pulmonary symptoms, including progressive dyspnoea, recurrent pneumothoraces and chylous effusions. Extrapulmonary lymphangioleiomyomatosis as the initial presentation of the disease is highly unusual. We describe a patient with extrapulmonary lymphangioleiomyomatosis presenting as jugular vein thrombosis related to lower neck lymphangioleiomyoma. CT study showed bilateral lung cysts with left-sided hydropneumothorax and retroperitoneal lymphadenopathy. A left lower neck cystic lesion was seen with thrombosis of the adjacent left subclavian and internal jugular veins.Lymphangioleiomyomatosis (LAM) is a rare interstitial lung disease that affects women exclusively, typically during their reproductive years. A small percentage of patients have LAM in association with tuberous sclerosis complex (TSC). LAM is characterised by the abnormal proliferation of smooth muscle cells (LAM cells) in the lungs and in the thoracic and retroperitoneal lymphatics. Affected patients are at risk of developing renal hamartomas or angiomyolipomas. Patients with LAM characteristically present with chronic dyspnoea and cough and less commonly with spontaneous pneumothorax.At radiography, LAM manifests with normal-to-large lung volumes and interstitial reticular opacities that may be subtle. Unilateral pneumothorax and unilateral or bilateral pleural effusions are frequent radiographic findings. CT and high-resolution CT demonstrate bilateral diffuse thin-walled cysts surrounded by normal lung parenchyma. CT may also demonstrate associated pleural effusion or pneumothorax, thoracic or abdominal lymphadenopathy and other abdominal abnormalities, including angiomyolipomas, lymphangioleiomyomas and ascites.Manifestation of extrapulmonary LAM as an initial presenting symptom is rare. The most common forms of extrapulmonary LAM include renal angiomyolipoma, enlarged abdominal lymph nodes and lymphangioleiomyoma. Less commonly, ascites and hepatic angiomyolipoma may be present. If the diagnosis of extrapulmonary LAM precedes that of pulmonary LAM, the patient usually develops chest symptoms within one to two years.     

Paraspinal interfaces in the lower thoracic area in children: evaluation by CT

Computed tomography was used to examine the three paraspinal interfaces (lines), consisting of the right and left paraspinal areas and the prespinal area in the lower thorax in 20 children. The abnormal CT findings were correlated with plain radiographic findings. The various disease contributing to paraspinal abnormality included malignant and benign neoplasm and inflammatory disease. Neuroblastoma was the most common entity. Fourteen of 20 patients had paraspinal masses representing either metastasis or lymphoma. Four had small pleural effusions and two had a combination of small pleural effusion and masses. Plain radiographs also showed the paraspinal masses, except in the prespinal area, where four of seven abnormalities seen with CT were not detected with plain radiographs. CT also better demonstrated the extent of involvement than did plain radiography.     

Evaluation of pleural and pericardial effusions by magnetic resonance imaging

MR examinations of 36 patients with pleural and/or pericardial effusions were retrospectively evaluated. The purpose of this study was to determine of MR imaging is capable of differentiating between pleural and pericardial effusions of different compositions using standard electrocardiogram (ECG)-gated and non-gated spin echo pulse sequences. Additional data was obtained from experimental pleural effusions in 10 dogs. The results of this study indicate that old hemorrhages into the pleural or pericardial space can be differentiated from other pleural or pericardial effusions. However, further differentiation between transudates, exudates and sanguinous effusions is not possible on MR images acquired with standard spin echo pulse sequences. Respiratory and cardiac motion are responsible for signal loss, particularly on first echo images. This was documented in experiments in dogs with induced effusions of known composition; "negative" T2 values consistent with fluid motion during imaging sequences were observed in 80% of cases. However, postmortem studies of the dogs with experimental effusions showed differences between effusions with low protein concentrations and higher protein concentrations. We conclude from our study that characterization of pleural and pericardial effusions on standard ECG-gated and non-gated MR examinations is limited to the positive identification of hemorrhage. Motion of the fluid due to cardiac and respiratory activity causes artifactual and unpredictable changes in intensity values negating the more subtle differences in intensity associated with increasing protein content.     

Pulmonary lymphangioleiomyomatosis: CT findings

Lymphangioleiomyomatosis, a rare disease occurring in women of childbearing age, is characterized by proliferation of smooth muscle in pulmonary lymphatic channels and mediastinal and abdominal lymph nodes. Chest radiographs typically reveal interstitial disease with normal lung volume. Pneumothorax and pleural effusions may be present. CT scans in eight patients with biopsy-proved pulmonary lymphangioleiomyomatosis were reviewed. The prominent feature of the disease was multiple thin-walled cysts throughout the lungs, best visualized on scans made with 1.5-mm collimation. Mediastinal and/or retrocrural lymphadenopathy, often not appreciated on the chest radiograph, was present in four of eight patients. CT can suggest a diagnosis of lymphangioleiomyomatosis when diagnosis by clinical presentation and chest radiographs is uncertain.     

CT demonstration of tethering of the lung by the pulmonary ligament

An unusual form of atelectasis has been detected on CT of a patient with large pleural effusions. It has been interpreted to be the result of tethering of the lungs to the mediastinum by the pulmonary ligaments, which may have lacked normal elasticity in this case because of prior irradiation. This appearance may simulate a collection of dense material on the surface of an effusion when there is no obvious air bronchogram present.     

Computed tomography in the evaluation of benign asbestos-related disorders.

High-resolution CT is more sensitive than chest radiography and conventional CT in the detection and assessment of benign asbestos-related pleural and parenchymal diseases. The HRCT features of asbestosis correlate with clinical and functional restriction. The specificity of HRCT findings of asbestosis needs further evaluation. Given its low cost and availability, chest radiography remains the mainstay of imaging in benign asbestos-related diseases. CT (conventional or high-resolution) is not recommended as a universal screening test in asbestos-exposed workers. It has a useful role in identifying and quantitating pulmonary fibrosis distinct from emphysema and pleural disease, in distinguishing pleural disease from normal extrapleural soft tissues, and in clarifying the confusing chest radiograph or conflicting pulmonary function data. CT is useful in excluding a mass that may be obscured by extensive pleural and parenchymal fibrosis and is helpful in the follow-up of benign fibrotic masses or in the direction of their biopsy.     

Imaging of the pleura

Pleural disease is a problem of global significance which causes significant morbidity and mortality. Pleural disease is usually first suspected on chest x-ray but further imaging, often ultrasound, is usually required as part of the diagnostic work-up. Complex imaging with computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)-CT are less often performed but are routinely required in patients with mesothelioma and occasionally required in patients with pleural infection and other pleural diseases. Cross-sectional imaging may be used to suggest the diagnosis of pleural disease, quantify disease severity, guide biopsy, and even predict prognosis. This review will focus on the contributions of CT, MRI, and PET to the management of pleural disease with discussion of their relative strengths and weaknesses.     

Intrathoracic manifestations of metastatic testicular seminoma: a comparison of chest radiographic and CT findings

The chest radiographs and CT scans of 200 patients with pure testicular seminoma were reviewed. The radiographs showed evidence of intrathoracic metastatic disease in 25 patients (12.5%). Of these, 17 had an abnormal mediastinal contour, seven had pulmonary metastases, five had pleural effusions, and two had discrete pleural masses. CT showed evidence of intrathoracic metastatic disease in 30 patients (15%). This included mediastinal nodal enlargement in 21, pulmonary metastases in 12, pleural effusions in six, and pleural masses in two. CT not only showed disease in five patients with normal chest radiographs, but also showed additional sites of disease in four other patients with abnormal chest radiographs. The results suggest that mediastinal nodal enlargement is the most common intrathoracic manifestation of metastatic testicular seminoma. CT is more accurate than chest radiography in the detection of metastatic seminoma in the chest and defines the extent of metastatic disease more precisely.     

Thoracic lymphoma

Mediastinal adenopathy is a common manifestation of HD in a usually predictable pattern involving anterior and middle mediastinal nodes with or without disease in the hili. Hilar adenopathy is uncommon without detectable mediastinal disease and the lung is virtually never involved alone. In NHL the pattern of disease is more unpredictable. Lung manifestations include direct extension from involved nodes, nodules with or without cavitation, atelectasis secondary to endobronchial or nodal obstruction and rarely an interstitial pattern. Pleural effusions are not uncommon, but solid pleural masses are less frequent. Invasion of the pericardium is not often seen, although masses are commonly seen along the pericardium. Invasion of the chest wall occurs particularly with involvement of internal mammary nodes. Occasionally, posterior nodes will invade the adjacent vertebrae and spinal canal. The chest wall may be invaded by enlarged axillary nodes. Isolated chest wall soft-tissue masses are not common and are usually a manifestation of NHL, especially large cell lymphoma. Although the chest radiograph should detect most intrathoracic disease. CT has been found a necessary adjunct in patients with HD for accurate staging and therapy, especially if radiotherapy is planned. CT has been found helpful in NHL for staging, especially for the pleura and chest wall. MR imaging has not been found to contribute additional useful information except in selected cases.