Introduction

Even though there are latest advances on chemotherapy patient care, the mortality by invasive fungal infection is still high among immunocompromised patients. Among more than 400,000 fungal species and 50 that can cause systemic infection, aspergillosis is the most common cause [1•, 2].

Invasive aspergillosis is one of the main complications during immunosuppression and on hematological malignancy patients. It is considered invasive whenever the fungal hyphae is found within the mucosa, submucosa, bone, or blood vessels [2]. Acute Invasive Fungal Sinusitis is the most lethal form of fungal sinusitis, with a mortality varying from 50 to 80%, is rare in immunocompetent patients, and is usually associated to poorly controlled diabetes and immunocompromised conditions [3, 4••].

Imaging studies are fundamental in the evaluation of fungal suspicion in patients with febrile neutropenia, after bone marrow transplantation, and during immunosuppression [5].

Nowadays, concerns related to radiation dose on image examinations are high, especially among young patients and those submitted to multiple studies during cancer treatment follow-up. The use of magnetic resonance (MR) should be considered for brain and facial sinuses evaluation.

Technical Considerations

The following sequences are considered usually sufficient to this evaluation: sinuses coronal STIR and axial T1 (Fig. 1) FLAIR. No contrast media is necessary to determine fungal infection.

Fig. 1
figure 1

8 years and 10 months old girl, post-bone marrow transplantation treating large cell non-Hodgkin’s lymphoma. a Coronal STIR shows low signal intensity within the walls of the hyperintense maxillary and ethmoid sinuses. b Unenhanced axial T1 shows characteristic hyperintense material within maxillary sinuses

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Imaging Findings

Facial sinuses and brain MRI should confirm the presence of fungal disease. The mucosa sinus edema is associated with a high STIR signal and low T1 (water). Whenever fungal material is present (Fig. 2) the sinus content becomes to a low STIR and a middle-high signal on T1. The T2 low signal or signal void is attributed to metal concentration, such as iron, magnesium, and manganese (Fig. 3) as well as the high protein and low free water content. Usually multiple sinuses are involved and they can be expanded. The adjacent fat and the posterior maxillary wall should also be evaluated, looking for inflammatory changes, obliteration of periantral fat, (Fig. 4) as well as the intraorbital and intracranial extension, leptomeningeal thickness, cerebritis, abscess, and intracranial granulomas, to characterize disease involvement and extension.

Fig. 2
figure 2

15-year-old girl post-bone marrow transplant to treat acute lymphocytic leukemia . a Coronal STIR shows signal void within the left maxillary sinus and hypersignal content within the ethmoid and right maxillary sinuses. b Unenhanced axial T1 shows hyperintense material within maxillary sinuses with anterior and posterior extension at the left sinus

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Fig. 3
figure 3

12-year-old boy post-bone marrow transplant to treat acute lymphocytic leukemia. a The coronal T2 MRI shows mixed signal intensity filling maxillary sinuses. b The axial T2 MRI shows mixed signal intensity filling maxillary sinuses

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Fig. 4
figure 4

12-year-old boy with relapsed acute myeloid leukemia. a Coronal T2 MRI shows mixed signal intensity filling right maxillary and right ethmoid sinuses. b Axial T2 MRI shows mixed signal intensity filling right maxillary and right ethmoid sinuses

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