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Inflammatory, Hypersensitivity and Immune Lung Diseases, including Parasitic Diseases.
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
The 'air crescent', 'meniscus' and 'target' signs (Illus. AIR CRESCENT SIGN) are produced by varying amounts of air separating a mycetoma or slough from an outer cavity wall. Whilst these appearances are usually due to an aspergilloma, similar appearances may sometimes be seen with actinomycosis, tuberculosis (e.g. haematoma within a TB cavity), septic pulmonary emboli, cavitating squamous or other carcinoma, sarcoma, a lung abscess or pulmonary gangrene, hamartoma within a cyst, leukaemic infiltrate (p. 5.48), a Rasmussen aneurysm (p. 7.12) or with hydatid disease (Fig. 19.7, p. 19.52).
Radiology of Infectious Diseases and Their Potential Mimics in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Jocelyn A. Luongo, Boris Shapiro, Orlando A. Ortiz, Douglas S. Katz
Aspergillus mold causes several distinct forms of pulmonary disease, ranging in severity from allergic reaction to angioinvasive pulmonary infection. This may present as fever in a neutropenic patient, not responsive to antibiotics. Invasive pulmonary aspergillosis frequently results in focal lung infarctions and cavitary transformation. The organism invades small blood vessels in the lung, the early appearance of which is relatively small pulmonary nodules with surrounding hemorrhage seen as ground-glass opacity secondary to hemorrhagic infarction, the “CT halo” sign (Figure 5.24). The vessel(s) involved can sometimes be identified (“feeding vessel” sign). The classic “air crescent” sign appears during the healing process, and is due to separation of infected necrotic lung from normal lung parenchyma or an aspergilloma that develops within a pre-existent cavity (Figure 5.25). Aspergillomas, which are not frankly angioinvasive in contrast to invasive aspergillosis but which may cause hemoptysis or may be asymptomatic, move freely within the cavity, and thus should change position between prone and supine imaging, a highly helpful identifying feature [77,78,94].
Test Paper 5
Published in Teck Yew Chin, Susan Cheng Shelmerdine, Akash Ganguly, Chinedum Anosike, Get Through, 2017
Teck Yew Chin, Susan Cheng Shelmerdine, Akash Ganguly, Chinedum Anosike
Angioinvasive pulmonary aspergillosis occurs almost exclusively in immunocompromised patients with severe neutropenia. Characteristic CT findings include nodules surrounded by a halo of ground-glass attenuation (halo sign) or pleura-based, wedge-shaped areas of consolidation. In neutropenia patients, the halo sign is highly suggestive of angioinvasive aspergillosis. However, a similar appearance has been described in infection by Mucorales, Candida, herpes simplex virus (HSV), cytomegalovirus (CMV), Wegener’s granulomatosis, Kaposi’s sarcoma and haemorrhagic metastases. Separation of fragments of necrotic lung (pulmonary sequestra) from adjacent parenchyma results in air crescents similar to those seen in mycetomas. The air crescent sign is usually seen after initiation of treatment and with resolution of the neutropenia. Airway invasive aspergillosis shows multiple centrilobular nodules and the tree-in-bud pattern.
National trends in incidence, prevalence and disability-adjusted life years of invasive aspergillosis in Iran: a systematic review and meta-analysis
Published in Expert Review of Respiratory Medicine, 2019
Mahin Tavakoli, Jamshid Yazdani Charati, Mohammad T Hedayati, Mahmood Moosazadeh, Parisa Badiee, Seyedmojtaba Seyedmousavi, David W Denning
The most common presenting sign in patients with suspected IA was fever. Abnormal imaging on CT scan or radiography suggestive of IPA included diffuse infiltration, halo and air crescent sign, consolidated area with or without cavity, nodules, and hydropneumothorax. Moreover, the most common sign of fungal endocarditis was fever, heart murmur, dyspnea, cough, general body pain, lower extremity pain, finger clubbing. The diagnosis of IA was based on culture or direct microscopy, serological tests (detection of Aspergillus antigens in BAL or serum including galactomannan (GM) and Beta-D- glucan assays) and molecular methods with detection of Aspergillus DNA in blood or respiratory samples. Overall, of 23 reports, 21 had available culture data in which 200 out of 396 cases (50.5%) had positive results. Supplementary table 2 shows a summary of GM-EIA characteristics. Nine studies applied the use of the BioRad GM-EIA assay on the BAL or serum for the diagnosis of IA with a GM index of ≥0.5, or ≥1 according to type of samples. The three types of PCR assays (ELISA, Real Time-PCR, and Nested-PCR) on various clinical samples were also used for the diagnosis of IA in 12 studies (Supplementary table 2).
Improving the rates of Aspergillus detection: an update on current diagnostic strategies
Published in Expert Review of Anti-infective Therapy, 2019
Jeffrey D. Jenks, Helmut J. F. Salzer, Martin Hoenigl
Similarly, radiographic findings are variable and differ significantly depending on host factors. Computed tomography (CT) scan of the chest is the imaging modality of choice to diagnose IPA. Classically, in neutropenic patients, IPA presents as pulmonary nodules with surrounding ground-glass infiltrates (termed the ‘halo sign’), which reflect angioinvasion and hemorrhage into the area surrounding the fungal infection. These nodules may cavitate and produce the ‘air-crescent sign’. Despite being typical signs of IPA on imaging, both the ‘halo sign’ and ‘air-crescent sign’ occur in <10% of neutropenic patients [35,36] and rarely occur in non-neutropenic patients [35], with other typical radiologic signs of IPA only occurring in about 30% of non-neutropenic patients [36]. In patients with underlying hematologic malignancies, CT pulmonary angiography (CTPA) may be more sensitive and specific for diagnosing angioinvasive IPA than traditional chest CT imaging, by revealing the vessel occlusion sign, but performance compared to traditional CT for other signs of IPA (halo sign, reverse halo sign, etc) is not known [37–39]. Coupling CT and positron emission tomography (PET) with ([18F]FDG), which is commonly used in cancer staging to assess metabolic activity, has limited utility in IFI’s as it cannot differentiate between infectious etiologies, cancer and other causes of inflammation [40,41].
Invasive pulmonary aspergillosis in patients with solid tumours: risk factors and predictors of clinical outcomes
Published in Annals of Medicine, 2018
Dima Dandachi, Rita Wilson Dib, Ana Fernández-Cruz, Ying Jiang, Anne-Marie Chaftari, Ray Hachem, Issam Raad
Many studies have shown that invasive aspergillosis does occur in critically ill patients and patients with other non-traditional risk factors [15,16]. The algorithm for the diagnosis of critically ill patients [10] was more useful than the EORTC/MSG criteria in this setting [3,17]. Our current study is not the first to recognize lung malignancy, COPD and critical illness as risk factors for IPA, but none of the previous studies showing these associations focused on patients with solid tumours [18–20]. Ohmagari, et al. published a case series of 13 patients with solid tumours and invasive aspergillosis diagnosed between 1999 and 2003 and reported that the lung was the most common site of infection [21]. In the literature and in our current study, most of the patients with IPA and no underlying hematologic malignancy presented with nonspecific symptoms and signs as well as nonspecific CT findings. Fever and hemoptysis were not predominant symptoms and the classical halo sign and the air-crescent sign were not described [22,23]. Studies done among critically ill patients have suggested combining 1,3-β-d-Glucan in the serum and GM from bronchoalveolar lavage to improve diagnostic accuracy for IPA [24–26].