Diagnostic Approach to the Patient with Necrosis on Lung Biopsy
Philip T. Cagle, Timothy C. Allen, Mary Beth Beasley in Diagnostic Pulmonary Pathology, 2008
Typical HRCT scan patterns have been described for many diseases including idio-pathic pulmonary fibrosis, sarcoidosis, lymphangetic tumor, hypersensitivity pneumonia, pulmonary alveolar proteinosis, chronic eosinophilic pneumonia and bronchiectasis. The diagnostic specificity of these patterns and the clinical utility of HRCT in the workup of diffuse pulmonary disease vary widely. Silicosis is characterized by reticulonodular lesions with small perilymphatic nodules with or without eggshell calcification (30). Pneumocystis pneumonia (PCP) typically has ground-glass opacities on HRCT: a normal HRCT has a nearly 100% negative predictive value for ruling out PCP (32). Mycobacterial and fungal diseases may be associated with multiple cavitary or noncavitary nodules typically >10 mm in size while smaller noncavitary nodules are often seen in viral pneumonias. Larger cavitary nodules as well as scattered alveolar opacities can be seen in patients with WG. The “halo sign” and “reversed halo sign” on HRCT have been associated with specific diseases. The “halo sign” is a rim of ground-glass opacity completely encircling a central nodule or mass and is seen with invasive fungal infections, WG, and malignancies. The reversed halo sign is relatively specific but insensitive for cryptogenic organizing pneumonia (COP) (32,33).
Disorders of larynx, trachea and upper airway
Brice Antao, S Irish Michael, Anthony Lander, S Rothenberg MD Steven in Succeeding in Paediatric Surgery Examinations, 2017
Oesophageal foreign bodies that go unrecognised can cause airway obstruction and stridor through chronic swelling of the tracheo-oesophageal septum. The most common foreign bodies of the oesophagus are coins and batteries. There are characteristic images for these two objects that may mimic each other. The use of posterior–anterior films as well as lateral films may show the foreign body and outline its shape, such that the step-off of one side of a disc battery may be recognised. Two coins, however, may be stacked and appear similar, and it is not uncommon to have two foreign bodies, so evaluation for a second foreign body is often necessary. A halo sign is a circumferential rim of decreased or increased opacity caused by the pattern of a button battery and is distinctive in appearance.
Invasive aspergillosis
Mahmoud A. Ghannoum, John R. Perfect in Antifungal Therapy, 2019
When a pulmonary IA is suspected, a high-resolution computed tomography (CT) scan is recommended [10,86,87]. Pulmonary nodules are the most common findings in early IPA in neutropenic patients and HSCT recipients and can be easily missed by a regular chest radiograph [86,88]. The “halo sign,” a haziness surrounding a nodule or infiltrate, is a characteristic chest CT feature of angioinvasive organisms and is highly suggestive of IPA in patients with prolonged neutropenia. Other findings on chest CTs may include consolidative lesions, wedge shaped infarcts, cavitation, and pleural effusions. Analysis of the high-resolution CT images of patients with probable and proven IPA showed that those with a halo sign at initiation of antifungal therapy had a significantly better response and greater survival than those presenting with other CT images [86]. In patients with cerebral or sinus IA, magnetic resonance imaging (MRI) is the preferred modality and allows early detection of inflammatory soft tissue edema, bone destruction, or invasion into adjacent structures and guides the subsequent diagnostic approach and surgical management [10,89,90].
Associations among temporal and large artery abnormalities on vascular ultrasound in giant cell arteritis
Published in Scandinavian Journal of Rheumatology, 2021
MA DiIorio, PS Sobiesczcyk, C Xu, W Huang, JA Ford, SS Zhao, DH Solomon, WP Docken, SK Tedeschi
Individual arteries were designated as having no vasculitis-related abnormality, halo sign, hyperechoic wall thickening without halo sign, stenosis, and/or occlusion. The halo sign was defined as homogeneous, circumferential hypoechoic wall thickening visualized in longitudinal and transverse views (Figure 1) (17, 29, 30). Hyperechoic wall thickening was defined by circumferential wall thickening visualized in longitudinal and transverse views, hyperechogenicity compared to adjacent arterial segments within the same artery, and the absence of the halo sign or arteriosclerosis (Figure 1). Stenosis was defined as more than two-fold increased velocity in the artery segment distal to the affected artery, along with arterial waveform abnormality. Occlusion was defined as complete absence of flow. For stenosis or occlusion to be counted as attributable to arteritis, the halo sign or hyperechoic wall thickening without halo sign was required in that artery.
ANCA associated vasculitis (AAV): a review for internists
Published in Postgraduate Medicine, 2023
Kinanah Yaseen, Brian F. Mandell
Respiratory involvement is very common in both MPA and GPA. GPA commonly affects the pulmonary parenchyma (85%) and bronchial tree (6%) [18] during the disease course and may present as cough, dyspnea, chest discomfort, hemoptysis, alveolar hemorrhage, pulmonary infiltrates on chest images or inflammatory changes of circumferential mucosal thickening and ulceration of lower airways on flexible bronchoscopy [10]. Solitary or multiple nodules can range in size from a few millimeters to several centimeters with frequent cavitation and sometimes exhibiting a ‘halo sign,’ which can the result from adjacent parenchymal hemorrhage [10,19]. However, the halo sign may also be seen in patients with invasive aspergillosis. Both thick- and thin-walled cavities may be present. Cavities must be monitored radiographically to confirm response to therapy, almost half resolve over time but some heal with residual fibrosis or remain unchanged [19].
Human and novel coronavirus infections in children: a review
Published in Paediatrics and International Child Health, 2021
Nipunie Rajapakse, Devika Dixit
Abnormal chest computed tomography (CT) images have been identified in asymptomatic children and adults infected with SARS-CoV-2 [131]. Some infected children may have normal CT chest imaging, especially early in the course of infection (187). Similar to what has been seen in adults, typical chest CT findings in children have included unilateral or bilateral, peripherally located ground-glass opacities consistent with viral pneumonia [187–189]. Halo sign was a unique feature seen in some paediatric CT scans that has not been commonly seen in adults [188]. Lu et al. reported ground-glass opacities in one-third of 171 children with COVID-19 [131]. As with many pulmonary infections, resolution of radiographical abnormalities may lag behind clinical improvement [190].
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