Learning objectives
Review the imaging features of the spectrum of pulmonary aspergillosis illustrated with cases from our practice.
Highlight the important features that enable the radiologist to distinguish between the forms of pulmonary involvement,
and the impact these have on clinical management.
Background
Aspergillosis is a mycotic infection typically caused by Aspergillus fumigatus though other aspergillus specifies may be implicated.
Pulmonary involvement is broadly classified into invasive and non-invasive disease.
Chest radiography and chest computed tomography (CT) play an important role in the investigation of this respiratory pathogen because the main portal of entry of the spores is via the lung.
Radiologists must therefore be able to distinguish the various forms of aspergillus infection as this impacts on clinical management.
Imaging findings OR Procedure details
Non-invasive disease
Subdivided into saprophytic (aspergilloma) and allergic bronchopulmonary aspergillosis (ABPA).
Aspergilloma
Aspergillomas appear as a mobile and rounded soft tissue nodule surrounded by a ring of air within a lung cavity synonymously with the air crescent sign.
These are the most common radiographic manifestation of aspergillus infection (Figures 1 and 2).
The differential diagnosis for the air crescent sign includes echinococcal cyst,
TB,
Rasmussen aneurysm,
lung abscess,
bronchogenic carcinoma,
haematoma or pneumocystis infection.
The aspergilloma classically moves when a patient changes position.
Associated with...
Conclusion
Pulmonary aspergillosis has a spectrum of appearances which impact on a patient’s management and prognosis.
Radiologists are important in guiding the multidisciplinary approach to investigation and treatment.
References
Spectrum of pulmonary aspergillosis: Histologic,
clinical and radiologic findings; Franquet T,
Muller N,
Gimenez A,
Guembe P,
De La Torre J and Bague S; Radiographics 2001; 21; 825-837
Pulmonary aspergillosis: a clinical review; Kousha M,
Tadi R and Soubani A; European Respiratory Review; 2011; 20; 121; 156-174