Differentiating diaphragmatic paralysis and eventration.

RATIONALE AND OBJECTIVES: Although elevation of the diaphragm can be appreciated on conventional PA and lateral chest radiography, the modality is commonly viewed as inadequate to differentiate diaphragmatic paralysis from eventration. Our objective was to qualitatively and quantitatively measure the utility of chest radiography in determining the presence or absence of diaphragmatic paralysis in patients with an elevated diaphragm. MATERIALS AND METHODS: A retrospective analysis of chest radiographs in 32 patients, whom underwent fluoroscopic sniff test for elevated diaphragm, was performed. Diaphragm function was graded by a senior radiology resident, as either "paralyzed" or "non-paralyzed," based on appearance/shape of elevated hemidiaphragm on PA and lateral radiograph. The diaphragm position and shape for all patients were determined using measurements relating to skeletal structures and radius of curvature, respectively. These results were correlated with the results of the fluoroscopic sniff tests. RESULTS: Of 32 patients with elevated diaphragm on chest radiograph, 17 had diaphragmatic paralysis confirmed with fluoroscopic sniff test. Our results indicate that the radius of curvature or shape of the diaphragm on lateral chest radiograph is the most important factor for detection of the presence or absence of diaphragmatic paralysis. HH/APD > 0.28 suggests against paralysis. CONCLUSION: Conventional chest radiography appears to be a useful modality for assessment of the functional status of an elevated diaphragm. Based on our results, evaluation of the shape of an elevated diaphragm may preclude the need for fluoroscopic sniff test to determine diaphragmatic paralysis.

Cervical thoracic duct cyst.

Thoracic duct cysts are rare lesions presenting as mediastinal or supraclavicular masses. We report a case of a 77-year-old female who presented with a left supraclavicular mass. A cervical thoracic duct cyst was suspected after contrast-enhanced computed tomography (CT) of the neck and chest. Diagnosis was confirmed by ultrasound-guided cyst aspiration and lymphangiography. Therapeutic embolization of the thoracic duct was unsuccessful. Definitive treatment was achieved with thoracic duct ligation using video-assisted thoracoscopic surgery (VATS) followed by surgical excision of the cyst. This is believed to be the first report of using minimally invasive surgery for thoracic duct ligation in the treatment of a thoracic duct cyst.

Lymphocytic interstitial pneumonitis in a patient with systemic lupus erythematosus: radiographic and high-resolution CT findings.

Reports associating lymphocytic interstitial pneumonitis (LIP) and systemic lupus erythematosus (SLE) are exceedingly rare. This case demonstrates high-resolution CT (HRCT) findings of LIP including multiple thin-walled cysts throughout the lungs, which are known to occur in LIP, but have not been described in the radiologic literature in association with SLE.

Multidetector pulmonary CT angiography: advances in the evaluation of pulmonary arterial diseases.

Multidetector CT (MDCT) has a primary role in the evaluation of pulmonary artery diseases. Contrast-enhanced MDCT studies are ideally suited for assessment of pulmonary arterial hypertension (PAH) and pulmonary thromboembolic disease. It has become the primary modality to diagnose acute and chronic thromboembolic disease. Its role in the evaluation of pulmonary hypertension is evolving, allowing the radiologist to assess the presence of disease and differentiating intrinsic versus extrinsic pulmonary arterial pathology. An understanding of pulmonary CT angiography, its appropriate application, associated pitfalls, contrast dynamics, and thin-section CT pulmonary and cardiac anatomy is necessary for accurate interpretation by the radiologist. In addition to assessing the pulmonary arteries MDCT has the implicit advantage of thin-section lung parenchymal imaging, a feature that often renders an alternative diagnosis when symptoms of pulmonary arterial disease occur.

Contrast dynamics during CT pulmonary angiogram: analysis of an inspiration associated artifact.

OBJECTIVE: Several artifacts have been observed during contrast-enhanced CT of the pulmonary arteries. We describe a physiological artifact caused by a transient interruption of the contrast column in the pulmonary arteries associated with inspiration immediately prior to imaging. This results from a variable inflow of unopacified blood from the inferior vena cava (IVC). MATERIALS AND METHODS: From 327 consecutive pulmonary CT-angiograms, all performed on a single detector scanner at 3 mm collimation (1.5 mm incremental reconstruction), 50 positive studies, 46 indeterminate studies, and 33 negative studies (129 exams) were retrospectively reviewed by a blinded observer to determine the frequency of the described contrast interruption, its severity (mild, moderate, or severe), and its possible contribution to misinterpretation of studies. The numerical change in Hounsfield units was assigned within the right ventricular chamber for each examination to correlate with the subjective evaluation of severity. Statistical significance was determined with P = 0.05%. RESULTS: The artifact was present in 48 (37.2%) of the 129 evaluated studies. It was greater in frequency (50.0%) with the negative studies. The presence was 25% with positive studies and 36.7% with indeterminate exams. The interruption was more often mild (<100 HU change) in severity (45.8%). Three (6.6%) definite false positives were detected where the misinterpretation was directly attributed to the artifact. Three (6.6%) other examinations called positive were also directly related to the interrupted contrast column. However, since no further pulmonary vascular evaluation was performed, these examinations can only be considered indeterminate. Two of the latter 3 studies demonstrated a severe (>150 HU change) and the other study demonstrated a moderate (100-150 HU) interruption of contrast opacification. CONCLUSIONS: During inspiration, there is a variable increase in unopacified venous blood from the IVC, briefly diluting the contrast column entering from the SVC. This interruption is common, though usually mild in severity. However, a short severe interruption of vascular opacification can lead to misinterpretation as a pulmonary embolus or contribute to an indeterminate examination.

Pulmonary Langerhans cell histiocytosis: emerging concepts in pathobiology, radiology, and clinical evolution of disease.

Pulmonary Langerhans cell histiocytosis (PLCH) is an uncommon disorder of adult smokers associated with a significant morbidity. Arising from the aberrant accumulation of Langerhans and other immune cells, PLCH tends to cause a relatively isolated pulmonary involvement as compared to other forms of Langerhans cell (LC) and histiocytic disorders. Increased knowledge of cytokine triggers, dendritic cell trafficking, and clonality of LC populations in PLCH have resulted in an improved understanding of the pathobiology of PLCH. High-resolution CT (HRCT) of the chest has led to better appreciation of nodular and cystic radiographic abnormalities characteristic of the disease. Correlation of HRCT abnormalities with lung pathologic changes has led to an improved comprehension of clinical evolution of PLCH. Current clinical predictors for PLCH outcomes remain poor, although long-term follow-up and radiologic monitoring may help to define disease progression. This review discusses advances in PLCH emphasizing the etiopathologic bases of the disease and currently available radiologic modalities for monitoring disease progression.

Diffuse lung disease in the immunocompromised non-HIV patient.

Physicians are encountering an increasing number of patients with various levels of immunosuppression, such as patients with AIDS, transplant recipients, patients on immunosuppressive therapy, and those with congenital immune defects and malignancy. This results in a greater diagnostic dilemma for the medical community because of the significant increased risk of opportunistic infections and noninfectious complications, as well as a more aggressive clinical course with typical pathogens. [figure: see text] Furthermore, it is not just the pathogens that are changing but also their clinical and radiographic presentations. The radiologist has a large role in not only detecting the presence of disease but also in narrowing the differential possibilities. This can be an overwhelming task given the wide variety of presentations of diseases on radiographs. However, by understanding the level and degree of the patient's immunosuppression, the radiologist may anticipate the most likely pulmonary complications. By using the radiographic morphology, distribution, and temporal evolution of the abnormalities, a manageable differential diagnosis can be created for referring clinicians.

Pulmonary complications in bone marrow transplantation.

This article reviews the most common pulmonary complications after bone marrow transplantation (BMT) and their radiologic presentations. An approach emphasizing the common complications that occur in relation to the immunosuppression recovery timeline is presented. An update on newer techniques of marrow transplantation and preparatory regimen drugs will be discussed. These newer techniques may have an effect on the radiologic appearance of some BMT complications. The diagnostic approach, management, and some evolving therapies of BMT patients with pulmonary complications will also be discussed.