Imaging of the post-radiation chest in lung cancer.

Radiation therapy using conventional fractionated external-beam or high-precision dose techniques including three-dimensional conformal radiotherapy, stereotactic body radiation therapy, intensity-modulated radiation therapy, and proton therapy, is a key component in the treatment of patients with lung cancer. Knowledge of the radiation technique used, radiation treatment plan, expected temporal evolution of radiation-induced lung injury and patient-specific parameters, such as previous radiotherapy, concurrent chemoradiotherapy, and/or immunotherapy, is important in imaging interpretation. This review discusses factors that affect the development and severity of radiation-induced lung injury and its radiological manifestations with emphasis on the differences between conventional radiation and high-precision dose radiotherapy techniques.

Integration of peripheral blood biomarkers with computed tomography to differentiate benign from malignant pulmonary opacities.

Our purpose was to determine whether peripheral blood biomarkers MUC1 and CK19 could be used to complement imaging studies in differentiating benign from malignant indeterminate pulmonary nodules or masses detected on computed tomography CT. One hundred and eighteen patients had a thoracic CT and blood drawn for tumor marker reverse transcriptase-polymerase chain reaction analysis. Thirty-five of the 118 patients had an indeterminate pulmonary nodular opacity on CT, and the findings then were correlated with the reverse transcriptase-polymerase chain reaction results. The sensitivity and specificity for the markers in determining malignancy was calculated. Thirteen of the 35 opacities on CT proved to be benign, and 22 proved to be lung cancer. Among the patients with indeterminate pulmonary abnormalities, polymorphic epithelial mucin protein 1 had a sensitivity and specificity for lung cancer of 100% and 46%, respectively. Cytokeratin 19 had a sensitivity and specificity for lung cancer of 95% and 8%, respectively. These preliminary data showed that serum biomarkers polymorphic epithelial mucin protein 1 and cytokeratin 19 were not specific for lung cancer, although patients with an indeterminate pulmonary abnormality and negative markers were unlikely to have lung cancer. Integration of imaging studies with the appropriate biomarkers may prove useful in evaluating indeterminate pulmonary nodules or masses.

Complications (excluding hyperinflation) involving the native lung after single-lung transplantation: incidence, radiologic features, and clinical importance.

PURPOSE: To determine the incidence, importance, and radiologic features of native lung complications after single-lung transplantation. MATERIALS AND METHODS: Seventeen (15%) of 111 single-lung transplant recipients developed native lung complications (excluding hyperinflation) 0-58 months (mean, 17 months) after transplantation. Complaints at presentation, culture or histopathologic results, diagnostic or therapeutic procedures, and outcome were recorded. Chest radiographs (n = 17) and computed tomographic (CT) scans (n = 8) obtained at time of diagnosis were reviewed. Serial radiographs were assessed for disease progression or improvement. RESULTS: The most common complications were infection (n = 10), caused by bacteria (n = 4), fungi (n = 4), or mycobacteria (n = 2), typically manifested as lobar or segmental opacities on chest radiographs or CT scans. Lung cancer manifested as a solitary well-circumscribed nodule (n = 1), multiple nodules (n = 1), or a hilar mass (n = 1). Five (29%) of 17 patients died of native lung complications. Seven patients underwent mediastinoscopy (n = 3), lobectomy (n = 2), thoracoscopic wedge resection (n = 2), tube thoracostomy (n = 2), or pneumonectomy (n = 1) for diagnosis or treatment. CONCLUSION: Native lung complications occurred in 17 (15%) single-lung transplant recipients, were most commonly due to infection or lung cancer, and caused serious morbidity or mortality in 12 (71%) of 17 patients affected.

Epithelioid hemangioendothelioma of the pleura: clinical and radiologic features.

OBJECTIVE: The purpose of our study was to describe the clinical and radiologic features of epithelioid hemangioendothelioma of the pleura. CONCLUSION: Pleural epithelioid hemangioendothelioma is an uncommon malignancy that typically affects older men, who present with chest pain and dyspnea. This lesion manifests on chest radiographs and CT scans with unilateral pleural fluid and nodular pleural thickening and appears similar to diffuse pleural carcinomatosis or mesothelioma.

Pulmonary drug toxicity: radiologic and pathologic manifestations.

Pulmonary drug toxicity is increasingly being diagnosed as a cause of acute and chronic lung disease. Numerous agents including cytotoxic and noncytotoxic drugs have the potential to cause pulmonary toxicity. The clinical and radiologic manifestations of these drugs generally reflect the underlying histopathologic processes and include diffuse alveolar damage (DAD), nonspecific interstitial pneumonia (NSIP), bronchiolitis obliterans organizing pneumonia (BOOP), eosinophilic pneumonia, obliterative bronchiolitis, pulmonary hemorrhage, edema, hypertension, or veno-occlusive disease. DAD is a common manifestation of pulmonary drug toxicity and is frequently caused by cytotoxic drugs, especially cyclophosphamide, bleomycin, and carmustine. It manifests radiographically as bilateral hetero- or homogeneous opacities usually in the mid and lower lungs and on high-resolution computed tomographic (CT) scans as scattered or diffuse areas of ground-glass opacity. NSIP occurs most commonly as a manifestation of carmustine toxicity or of toxicity from noncytotoxic drugs such as amidarone. At radiography, it appears as diffuse areas of heterogeneous opacity, whereas early CT scans show diffuse ground-glass opacity and late CT scans show fibrosis in a basal distribution. BOOP, which is commonly caused by bleomycin and cyclophosphamide (as well as gold salts and methotrexate), appears on radiographs as hetero- and homogeneous peripheral opacities in both upper and lower lobes and on CT scans as poorly defined nodular consolidation, centrilobular nodules, and bronchial dilatation. Knowledge of these manifestations and of the drugs most frequently involved can facilitate diagnosis and institution of appropriate treatment.

FDG PET of pleural effusions in patients with non-small cell lung cancer.

OBJECTIVE: We determined the ability of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to differentiate benign and malignant pleural effusions in patients with non-small cell lung cancer. MATERIALS AND METHODS: Over a 6-year period, we reviewed all patients with primary non-small cell lung cancer and a pleural effusion on staging CT who underwent FDG PET. We examined 25 patients (18 men and seven women; age range, 37-86 years; mean age, 65 years). FDG PET revealed positive findings if pleural activity was greater than background mediastinal activity; FDG PET revealed negative findings if pleural activity was the same as or less than background mediastinal activity. Results of FDG PET were correlated with pathologic diagnosis determined with thoracentesis or pleural biopsy. RESULTS: All patients had effusions on the same side as the primary tumor. Twenty-two patients had a malignant pleural effusion confirmed with thoracentesis (n = 19) or biopsy (n = 3). FDG PET revealed positive findings in 21 patients and negative findings in one. Three patients had no evidence of malignancy in the pleural space determined with cytologic findings (n = 2) or biopsy results (n = 1). FDG PET uptake revealed positive findings in one of these patients and negative findings in two. Therefore, of 22 patients with positive findings on FDG PET, 21 had pleural metastases, and of three patients with negative findings on FDG PET, one had metastases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET for detecting pleural metastases were 95%, 67%, 95%, 67%, and 92%, respectively. CONCLUSION: This study suggests that FDG PET may be useful in improving staging evaluation in patients with non-small cell lung cancer and a pleural effusion. Increased pleural FDG uptake usually indicates pleural metastases; however, because the number of benign effusions studied was small, the relevance of negative findings on FDG PET in this setting is uncertain.

Lung cancer and positron emission tomography with fluorodeoxyglucose.

Over the past years, positron emission tomography (PET) with fluoro-2-deoxy-D-glucose (FDG) has emerged as an important imaging modality. In the thorax, FDG-PET has been shown to differentiate benign from malignant pulmonary lesions and stage lung cancer. Preliminary studies have shown its usefulness in assessing tumor recurrence, and assisting in radiotherapy planning. FDG-PET is often more accurate than conventional imaging studies, and has been proven to be cost-effective in evaluating lung cancer patients. This review will discuss the current applications of FDG-PET as compared with conventional imaging in diagnosing, staging, and following patients with lung cancer.

Management of malignant pleural effusions and pneumothorax.

Pneumothorax may occur spontaneously or result from underlying lung disease or as a complication of interventional thoracic procedures. Percutaneous catheter placement enables safe and effective drainage of pneumothoraces with rapid relief of symptoms and restoration of vital capacity and oxygenation.

Percutaneous management of intrapulmonary air and fluid collections.

The radiologist's role in the management of intrapulmonary air and fluid collections is becoming more important. Improvements in percutaneous interventional techniques now allow the radiologist to offer patients an alternative treatment option with less morbidity and mortality than surgical resection. The use of CT allows optimal catheter placement and enables safe and effective percutaneous evacuation of intrapulmonary collections. In summary, image-guided percutaneous catheter drainage should (1) be the initial procedure performed to diagnose and treat lung abscesses not responding to conservative therapy; and (2) because of its effectiveness and safety, be considered as a treatment option in the management of symptomatic patients with intrapulmonary mycetomas.

MR imaging of mediastinal masses.

Although ongoing developments in MR imaging have resulted in improved image quality and decreased acquisition time, MR imaging is largely used as an adjunct to CT scanning in the evaluation of mediastinal abnormalities. In this role, MR imaging often provides additional information about the nature, location, and extent of disease. MR imaging is useful in confirming the cystic nature of mediastinal lesions that appear solid on CT and, by revealing small amounts of intralesional fat, can suggest the diagnosis of hemangioma, teratoma, or extramedullary hematopoesis. MR imaging is the preferred modality for imaging neurogenic tumors, because its multiplanar capability and high contrast resolution can best demonstrate the number and nature of the lesions (differentiating cysts from neoplasms), intraspinal extension, and craniocaudad extent. MR imaging is also especially useful for evaluating the mediastinum of patients for whom the administration of iodinated contrast material is contraindicated.

Solitary pulmonary nodules: Part I. Morphologic evaluation for differentiation of benign and malignant lesions.

The solitary pulmonary nodule is a common radiologic abnormality that is often detected incidentally. Although most solitary pulmonary nodules have benign causes, many represent stage I lung cancers and must be distinguished from benign nodules in an expeditious and cost-effective manner. Evaluation of specific morphologic features of a solitary pulmonary nodule with conventional imaging techniques can help differentiate benign from malignant nodules and obviate further costly assessment. Small size and smooth, well-defined margins are suggestive of but not diagnostic for benignity. Lobulated contour as well as an irregular or spiculated margin with distortion of adjacent vessels are typically associated with malignancy. There is considerable overlap in the internal characteristics (eg, attenuation, cavitation, wall thickness) of benign and malignant nodules. The presence of intranodular fat is a reliable indicator of a hamartoma. The presence and pattern of calcification can also help differentiate benign from malignant nodules. Computed tomography (CT) (particularly thin-section CT) is 10-20 times more sensitive than standard radiography and allows objective, quantitative assessment of calcification. Initial evaluation often results in nonspecific findings, in which case nodules are classified as indeterminate and require further evaluation to exclude malignancy. Growth rate assessment, Bayesian analysis, contrast material-enhanced CT, positron emission tomography, and transthoracic needle aspiration biopsy can be useful in this regard.

Solitary pulmonary nodules: Part II. Evaluation of the indeterminate nodule.

Various strategies may be used to evaluate indeterminate solitary pulmonary nodules. Growth rate assessment is an important and cost-effective step in the evaluation of these nodules. Clinical features (eg, patient age, history of prior malignancy, presenting symptoms, smoking history) can be useful in suggesting the diagnosis and aiding in management planning. Bayesian analysis allows more precise determination of the probability of malignancy (pCa). Decision analysis models suggest that the most cost-effective management strategy depends on the pCa for a given nodule. At contrast material-enhanced computed tomography, nodular enhancement of less than 15 HU is strongly predictive of a benign lesion, whereas enhancement of more than 20 HU typically indicates malignancy. At 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography, lesions with low FDG uptake are typically benign, whereas those with increased FDG uptake are typically malignant. Results of transthoracic needle aspiration biopsy influence management in approximately 50% of cases and, in indeterminate lesions with a pCa between 0.05 and 0.6, is the best initial diagnostic procedure. It is optimally used in peripheral nodules and has been reported to establish a benign diagnosis in up to 91% of cases. Although there is no one correct management approach, the ability to distinguish benign from malignant solitary pulmonary lesions has improved with the use of these strategies.

Thoracic manifestations of neurofibromatosis-I.

The intrathoracic manifestations of neurofibromatosis-I are protean and can, on occasion, mimic those of malignancy. Many of the intrathoracic findings are characteristic of the disease and can be expected to be present. Knowledge of the full spectrum of radiologic findings can thus be useful in preventing diagnostic error. Furthermore, an unexpected finding, such as rapid growth of a neural tumor, should be recognized as an atypical feature (suspicious for malignant degeneration) and result in further evaluation.

Positron emission tomography imaging in the thorax.

Positron emission tomography imaging has proven valuable in the evaluation and management of thoracic abnormalities. It is more accurate than CT or MR imaging in characterizing indeterminate focal abnormal pulmonary opacities, staging lung cancer, and assessing the therapeutic response. PET imaging in lung cancer also appears to be cost-effective, particularly with whole-body studies. The metabolic and physiologic abnormalities used in FDG-PET imaging, rather than conventional anatomic or morphologic characteristics, provide an invaluable model for the future of tumor imaging.

Pulmonary nontuberculous mycobacterial infection: radiologic manifestations.

The nontuberculous mycobacteria (NTMB) are a group of bacteria that can infect the cervical lymph nodes, skin, soft tissues, and lung. Pulmonary NTMB disease is increasing in prevalence and is most commonly caused by Mycobacterium avium-intracellulare or M kansasii. Occasionally, M xenopi, M fortuitum, or M chelonae also causes pulmonary disease. Diagnosis of pulmonary NTMB infection is often difficult because isolation of the organism from sputum or bronchoalveolar lavage fluid can represent airway colonization. The radiologic manifestations of pulmonary NTMB infection are protean and include consolidation, cavitation, fibrosis, nodules, bronchiectasis, and adenopathy. Pulmonary NTMB infection has five distinct clinicoradiologic manifestations: (a) classic infection, (b) nonclassic infection, (c) nodules in asymptomatic patients, (d) infection in patients with achalasia, and (e) infection in immunocompromised patients. Although classic NTMB infection may be indistinguishable from active tuberculosis, it is usually more indolent. The radiologic features of nonclassic NTMB infection are characteristic: bronchiectasis and centrilobular nodules isolated to or most severe in the lingula and middle lobe. In patients with acquired immunodeficiency syndrome, mediastinal or hilar adenopathy is the most common radiographic finding. Knowledge of the full spectrum of clinical and radiologic features of pulmonary NTMB infection is important to facilitate diagnosis and treatment.

Cystic fibrosis: usefulness of thoracic CT in the examination of patients before lung transplantation.

PURPOSE: To evaluate the usefulness of thoracic computed tomography (CT) in the pre-lung transplantation examination of patients with cystic fibrosis (CF). MATERIALS AND METHODS: Fifty-six patients (age range, 12-42 years) with CF were evaluated for possible lung transplantation from 1991 to 1997. Twenty-six of these patients underwent bilateral lung transplantation, 19 were awaiting transplantation at the time of the study, seven died before transplantation, and four were excluded for psychosocial concerns. Preoperative chest radiographic and CT findings were reviewed and correlated with clinical, operative, and pathology records. RESULTS: In seven patients, discrete, 1-2-cm pulmonary nodules were detected at CT. Five of these patients underwent transplantation; the nodules were found to be mucous impactions. No malignancy was found in any of the patients who underwent transplantation. Pretransplantation sputum cultures grew Aspergillus fumigatus in seven patients, none of whom had radiologic findings suggestive of Aspergillus infection. Radiographic or CT findings were suggestive of mycetoma in five cases, but no such tumors were found at transplantation. The accuracies of chest radiography and CT for the detection of pleural disease in 48 hemithoraces were 81% (n = 39) and 69% (n = 33), respectively. The radiologic findings of pleural thickening did not influence the surgical approach in any patient. CONCLUSION: Thoracic CT has little utility in the routine pre-lung transplantation examination of patients with CF.