Jeffrey P. Kanne

Role of Computed Tomography and Magnetic Resonance Imaging for Deep Venous Thrombosis and Pulmonary Embolism

Abstract—During the 1990s, computed tomography (CT) and magnetic resonance (MR) imaging underwent extensive technological advancement and expanded clinical use in patients with venous thromboembolic disease, particularly with regard to evaluation of the pulmonary vasculature. In many institutions, helical (spiral) CT pulmonary angiography has become the initial imaging study of choice to evaluate patients with suspected pulmonary embolism, supplanting ventilation/perfusion scintigraphy. In addition, CT venography of the pelvis and lower extremities is often incorporated into the CT angiography protocol to identify or exclude concurrent deep venous thrombosis. MR pulmonary angiography and MR venography are second-line diagnostic tools because of their higher cost, limited availability, and other logistical constraints. As the technology improves and becomes more widely available, MR imaging may play a greater role in the evaluation of patients with venous thromboembolic disease.

The diagnostic accuracy of computed tomography angiography for traumatic or atherosclerotic lesions of the carotid and vertebral arteries: a systematic review

INTRODUCTION Helical computed tomography angiography (CTA) has become an established technique for evaluating atherosclerosis of the cerebrovascular arteries. However, the role of CTA in penetrating and blunt trauma to the carotid and vertebral arteries is not well defined. We conducted a systematic literature review to determine the diagnostic accuracy of CTA for atherosclerotic, penetrating and blunt lesions in the carotid and vertebral arteries. METHODS We searched MEDLINE and EMBASE databases to identify studies evaluating the diagnostic accuracy of CTA of the carotid and vertebral arteries published between January 1, 1992 and December 31, 2002. Two reviewers independently assessed abstracts and full text to determine study eligibility. Information on methodological quality, imaging technique and diagnostic accuracy was abstracted from all eligible studies by three independent reviewers. We pooled sensitivity and specificity data from diagnostic accuracy studies of high methodological quality. RESULTS Forty-three articles met the inclusion criteria and were included in the review. Thirty studies examined atherosclerotic disease, two blunt trauma, two penetrating trauma and nine examined patients with other pathology. Pooled data from 15 higher quality studies demonstrated that CTA had a sensitivity of 95% (91-97% CI) for detecting severe (>70%) atherosclerotic stenosis of the carotid artery. The specificity of CTA for severe stenosis was also high 98% (96-99% CI). CTA remained a sensitive technique (95%; 93-97% CI) when the criterion for a positive result is relaxed to moderate or greater (>30%) stenosis. Two studies raised concerns about the use of CTA in the blunt trauma setting, suggesting that CTA may not be sensitive for detecting small intimal injuries, although both of these studies used older technologies for either obtaining or viewing images. Conversely, two penetrating trauma studies concluded that the sensitivity of CTA was high. CONCLUSIONS Our findings demonstrate that CTA is both a sensitive and specific imaging technique for identifying severe atherosclerotic stenosis and occlusion of the carotid arteries. However, there is currently not enough high quality evidence to accurately estimate the sensitivity and specificity of CTA in the setting of blunt or penetrating trauma.

Occupational lung disease.

Despite federally mandated safety standards, occupational lung disease remains one of the most common work-related injuries. Inhaled dust can result in a range of tissue injury in the lung and can lead to significant respiratory insufficiency causing death. Although silicosis and coal workers pneumoconiosis are becoming less common, hypersensitivity pneumonitis is increasingly recognized as an occupational lung disease with new antigens being introduced annually. Imaging, particularly high-resolution computed tomography, is central to the management of occupational lung disease and is useful in diagnosis, assessment of disease activity, and evaluating response to therapy.

Wegener's Granulomatosis in the Chest: High-Resolution CT Findings

OBJECTIVE Wegeners granulomatosis is an uncommon necrotizing vasculitis having variable presentations in the chest that are best depicted on high-resolution CT. Imaging findings may include nodules, which may cavitate; ground-glass opacity secondary to pulmonary hemorrhage; and airway stenoses and ulcerations. Active Wegeners granulomatosis can mimic pneumonia, septic emboli, and metastases. CONCLUSION This article will illustrate the high-resolution CT findings of Wegeners granulomatosis in the chest.

High-resolution CT findings of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation.

Purpose To describe the high-resolution computed tomography (CT) findings occurring in bronchiolitis obliterans syndrome (BOS) after hematopoietic stem cell transplantation (HSCT) and to determine the relationship between pulmonary function tests (PFTs) and air trapping detected on expiratory CT. Materials and Methods The high-resolution CT scans of 33 patients who underwent HSCT and subsequently developed BOS were evaluated by 2 observers blinded to PFT results. Scans were ranked for degree of air trapping and scored for findings of bronchial wall thickening, bronchiectasis, and centrilobular opacities. Air-trapping rank was correlated with the degree of airflow obstruction as determined by PFTs. Results The ranking of air trapping correlated significantly with 1-second forced expiratory volume (P=0.001), 1-second forced expiratory volume /forced vital capacity (P<0.001), residual volume (P<0.001), carbon monoxide diffusion capacity (P=0.023), but not forced vital capacity (P=0.14) or total lung capacity (P=0.07). Bronchial wall thickening occurred in 73.0%, predominantly in lower lobes (P=0.007), but was mild. Bronchiectasis occurred in 42.4% and centrilobular opacities in 39.4%. Conclusions In BOS developing after HSCT, air trapping is the principal finding on CT, and its severity correlates with PFTs. Bronchial wall thickening is common, but almost always mild; bronchiectasis and centrilobular opacities occur in less than half of cases and are also mild.

Common and Uncommon Manifestations of Wegener Granulomatosis at Chest CT: Radiologic-Pathologic Correlation

Wegener granulomatosis is an uncommon necrotizing vasculitis that classically manifests as a clinical triad consisting of upper and lower airway involvement and glomerulonephritis. Other less frequently involved organ systems include the central and peripheral nervous system and large joints. The diagnosis is based on a combination of clinical and laboratory findings. Because thoracic involvement often predominates, chest radiographic findings are often the first to suggest the diagnosis. However, chest computed tomography (CT) has superior sensitivity and specificity for evaluation of the airways, lung parenchyma, and mediastinum, particularly with the use of multiplanar reformatted and three-dimensional images. Common pulmonary radiologic findings include waxing and waning nodules, masses, ground-glass opacities, and consolidation. Airway involvement is usually characterized by circumferential tracheobronchial thickening, which can be smooth or nodular. Pleural effusions are the most common manifestation of pleural disease and can result from primary involvement or be secondary to renal failure. Mediastinal lymphadenopathy is a nonspecific finding and is usually reactive. Uncommon thoracic radiologic manifestations include involvement of the heart and great vessels. CT is the imaging modality of choice for diagnosis, surveillance, and follow-up in patients with Wegener granulomatosis.

Vanishing Lung Syndrome (Giant Bullous Emphysema): CT Findings in 7 Patients and a Literature Review

Purpose we reviewed the imaging findings in 7 patients with idiopathic giant bullous emphysema. This is a chronic, progressive condition usually affecting young male smokers and is characterized by giant emphysematous bullae, which commonly develop in the upper lobes. Extensive paraseptal emphysema coalesces to form giant bullae, compressing the normal lung parenchyma and often displacing it centrally. These bullae occupy at least one-third of a hemithorax. Materials and Methods Seven patients with chest radiographic evidence of a bulla or bullae occupying at least one-third of a hemithorax, who had also been examined with high-resolution computed tomography (HRCT), were included in this retrospective study. On HRCT scans, the size, location, and distribution of the bullae were documented and categorized as either subpleural or central. Results The HRCT scan findings in all 7 study patients included numerous bullae ranging in size from a few centimeters in diameter to giant bullae nearly filling an entire hemithorax, mimicking a pneumothorax. Five of the 7 patients had extensive upper lobe predominant bullae, 4 of the 7 patients showed severe bilateral disease with asymmetric involvement, 2 of the 7 patients demonstrated left lung predominance and whereas 1 patient showed right lung predominant disease. All of our patients had subpleural bullae, had parenchymal fibrosis, another had extensive subcutaneous emphysema, and 1 had accompanying bronchiectasis. Conclusions The predominant findings on HRCT scans are extensive paraseptal emphysema coalescing into giant bullae. HRCT is helpful in confirming the diagnosis of VLS, assessing the degree of the disease, and providing information to guide treatment.

Viral pneumonia after hematopoietic stem cell transplantation: high-resolution CT findings.

Hematopoietic stem cell transplantation (HSCT) is the treatment of choice for many hematologic malignancies and nonmalignant disorders of bone marrow function. Pulmonary infections from bacterial, fungal, and viral organisms are a major cause of morbidity and mortality in patients after HSCT. The radiographic and high-resolution computed tomography (HRCT) findings of the different lower respiratory tract viral infections are quite similar. Findings of viral pneumonia on HRCT include small poorly defined centrilobular nodules and patchy, often bilateral, areas of peribronchial ground-glass opacity and consolidation. Air trapping may be present because of associated bronchiolitis. Interlobular septal thickening, bronchial wall thickening, and tree-in-bud opacities may also be present. Advanced viral pneumonia with diffuse alveolar damage is characterized by patchy or confluent consolidation and ground-glass opacities. Although nonspecific, in the correct clinical setting, these HRCT findings can help suggest the diagnosis of viral pneumonia in recipients of HSCT.

Diffuse pulmonary ossification.

Diffuse pulmonary ossification (DPO) is an uncommon condition that is characterized by metaplastic bone formation in the lung parenchyma. It is usually not diagnosed clinically and may be apparent radiographically only when extensive. However, it is occasionally encountered at autopsy or on pathologic evaluation of surgical specimens. This article will review the clinical, histologic, and radiographic manifestations of DPO, focusing primarily on the chest radiograph and CT findings, both of which may be underappreciated, for even experienced radiologists may confuse DPO with other entities such as metastatic calcification as seen in chronic renal failure or chronic granulomatous disease.

Computed tomography of the pericardium and pericardial disease.

The spectrum of pericardial abnormalities includes congenital absence, pericardial cyst, pericarditis, effusion, constriction, tamponade, retained foreign body, and neoplasms. Because of it high spatial and temporal resolutions, multiplanar reconstruction capability, and large field of view, computed tomography (CT) is a very useful tool in the comprehensive anatomical and functional evaluation of the pericardium. Knowledge of normal pericardial anatomy, anatomic variants, and imaging appearances of various pericardial abnormalities is essential for accurate diagnoses and characterization. In this pictorial review, the CT appearances of the normal pericardium and pericardial abnormalities are discussed and illustrated.