Content area
Full Text
Pleural-related pathologies are frequently encountered on chest radiography and computed tomography (CT) studies. While general radiologists are likely familiar with entities such as pneumothoraces and simple pleural effusions, other pathologies may pose a diagnostic dilemma. We discuss three broad categories of pleural disease - neoplasia; infection and inflammation; and the unexpandable lung - with an emphasis on imaging features.
The pleura lines the thoracic cavity and comprises the visceral and parietal pleural layers. The inner visceral pleura covers the lungs and extends into the pulmonary fissures.1 The outer parietal pleura covers the mediastinum, diaphragm, and the innermost aspect of the chest wall. The potential space between the visceral and parietal pleura is the pleural space.
Pleural disease is most frequently encountered on chest radiography and CT, as these are routinely ordered in patients with signs and symptoms such as shortness of breath, cough, chest pain, or fever. Frontal and lateral chest radiographs are useful screening tools and can reveal many forms of pleural disease.
However, CT is the modality of choice for evaluating the pleura.1 In particular, a contrast-enhanced, thin-section CT of the chest with a scan delay of 60-90 seconds is optimal for assessing the visceral and parietal pleura, which together are normally less than 1 mm in thickness.2
Neoplasia
Metastasis
Metastasis is the most common neoplastic disease of the pleura; primary pleural tumors account for fewer than 5% of pleural neoplasms.3 Approximately 40% of pleural metastases are attributable to lung cancer, 20% to breast cancer, 10% to lymphoma, and 30% to various other primary malignancies.4 Pleural metastases may present as pleural effusions and should be included in the differential diagnosis of large, unilateral pleural effusions or loculated pleural effusions, especially in patients with a history of malignancy (Figure 1).
Such patients usually present with dyspnea and/or chest pain. The degree of dyspnea may not directly correlate to the volume of the effusion.5 Symptoms may relate to the patient's baseline pulmonary status and the rate of fluid accumulation.
The diagnosis of malignant pleural effusion is most commonly established by thoracentesis, with subsequent pleural cytology. If a pleural biopsy is needed for diagnosis, positron emission tomography (PET) imaging or contrastenhanced CT (CECT) may elucidate optimal targets for tissue sampling.
Pleural metastases can also manifest as...