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Disorders of larynx, trachea and upper airway
Published in Brice Antao, S Irish Michael, Anthony Lander, S Rothenberg MD Steven, Succeeding in Paediatric Surgery Examinations, 2017
Charles M Myer IV, Charles M Myer III
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.
Clinical Cases
Published in S. J. Copley, J. P. Kanne, D. M. Hansell, Thoracic Imaging, 2014
S. J. Copley, J. P. Kanne, D. M. Hansell
63i. The HRCT shows a large nodule in the right upper lobe, with an indistinct peripheral margin, a so-called ‘halo’ of ground-glass opacity. A similar smaller nodule is located anteromedially. The halo sign is due to haemorrhage into the lung around a nodule and the commonest cause is infection, particularly invasive aspergillosis.
Pulmonary complications of bone-marrow and stem-cell transplantation
Published in Philippe Camus, Edward C Rosenow, Drug-induced and Iatrogenic Respiratory Disease, 2010
Bekele Afessa, Andrew D Badley, Steve G Peters
The radiographic findings of pulmonary aspergillosis include nodules, diffuse pulmonary infiltrates and cavitation.7 Nodules, masses and the ‘halo sign’ are more frequently seen in pulmonary aspergillosis compared to other pulmonary complications. The halo sign consists of a nodule surrounded by ground-glass attenuation due to coagulation necrosis and haemorrhagic infarction, whereas the ‘air crescent sign’ represents the development of necrosis. The halo sign is seen more often in neutropenic patients.69 Cavitation is a late finding in invasive pulmonary aspergillosis (Fig. 17.4). A recent study has shown that the ‘hypodense sign’, the presence of hypodensity in nodules or consolidations, may have high specificity for the diagnosis of invasive pulmonary aspergillosis.70 Since CT findings often precede plain radiography findings, chest CT should be performed in patients with suspected pulmonary aspergillosis.
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].
Current and innovative therapeutic strategies for the treatment of giant cell arteritis
Published in Expert Opinion on Orphan Drugs, 2021
Alwin Sebastian, Alessandro Tomelleri, Bhaskar Dasgupta
There is great interest in using imaging not only as a diagnosing tool but also as an aid to monitor GCA activity. ‘Halo sign’ is a recognized sign in ultrasound assessment to appreciate the vessel wall inflammation. A recent study showed that halo sign in temporal arteries was 82.5% sensitive in diagnosing GCA; however, this lowered to 60% when patients were on high dose GC (> 30 mg/day). This study also found that 42.9% of the patients had halo sign recurrence when the disease relapsed [132]. Our group showed a marked improvement of halo sign after treatment with tocilizumab [133]. Currently, we are assessing the role of halo score in diagnosis and prognosis in GCA [134].
Ultrasound centre frequency shifts as a novel approach for diagnosing giant cell arteritis
Published in Scandinavian Journal of Rheumatology, 2023
M Naumovska, R Sheikh, J Albinsson, B Hammar, U Dahlstrand, M Malmjsö, T Erlöv
The present study shows that ultrasound CFS can be used to differentiate temporal arteries with GCA from those without GCA. The main advantage of ultrasound CFS is that it is independent of the expertise of the examiner since the frequency distribution obtained is an objective measure and thus without interobserver variability. This is in contrast to traditional clinical ultrasound imaging based on B-mode images such as colour Doppler ultrasonography, which is dependent on the operator’s experience (21, 22), and may be affected by the choice of ultrasound window and colour gain. Despite this, colour Doppler ultrasonography has been used extensively for the examination of GCA (24–28). The most common sign for GCA on colour Doppler ultrasonography is a dark halo around the lumen of the temporal artery, called the halo sign, which is thought to be caused by oedema in the artery wall (27, 28). According to a meta-analysis in 2010, a unilateral halo sign has a specificity of 91% and sensitivity of 68%, but the specificity is greater when bilateral halo signs are present (24). However, it has been demonstrated that the halo sign can be easily provoked in healthy temporal arteries and can also be missed in diseased temporal arteries when applying inappropriate colour Doppler settings (21). In the TABUL study (Temporal Artery Biopsy vs Ultrasound in Diagnosis of GCA), the aim of which was to determine the diagnostic accuracy of temporal artery colour Doppler ultrasonography in comparison to TAB in the diagnosis of GCA, the specificity and sensitivity of colour Doppler ultrasound were found to be 81% and 54%, respectively (10). All ultrasound examiners in the TABUL study underwent training to standardize the examination. However, no previous experience of vascular ultrasound was required in the TABUL study, indicating that colour Doppler ultrasonography may have been limited by the operator’s experience.