Black Turbinate sign: MRI finding in acute invasive fungal sinusitis

A Retrospective Study of Imaging of Invasive Rhino-Orbital-Cerebral Mucormycosis in the COVID-19 Pandemic in a Tertiary Care Center

Aim The study aims to analyze the imaging findings of invasive rhino-orbital-cerebral mucormycosis (ROCM) in patients who had COVID-19. Materials and methods This retrospective descriptive study was done on confirmed (culture and histopathology) patients who had a COVID-19 infection. The data was collected from the record section from May 2021 to June 2021. Imaging data were analyzed, and findings were tabulated according to statistical methods. Results Radiological evaluation, including CT and MRI, was done in 48 cases. The ethmoid sinus was the most common sinus involved in 60.41% of cases, followed by the maxillary sinus (52.09%). Unilateral pansinusitis was observed in 21 cases (43.75%). Among periantral extensions, retroantral fat involvement was the most common finding, seen in 24 cases (50%). Lamina papyracea and the walls of the maxillary sinus were involved in eight cases (16.67%). A total of 38 cases (79.17%) exhibited involvement of the extraconal compartment, while 32 cases (66.67%) showed involvement of the intraconal compartment. In intracranial involvement, infarct was noted in 13 cases (27%), and cavernous sinus involvement in nine cases (18.75%). Conclusions ROCM is a life-threatening fungal infection in immunocompromised patients, especially diabetics. Imaging of ROCM plays a pivotal role in early diagnosis, the extent of disease, surgical planning, prognosis, and the response to treatment. Radiologists must know the imaging features and patterns of extension of ROCM.

The potential for rapid antigen testing for mucormycosis in the context of COVID-19

INTRODUCTION

Mucormycosis is a highly aggressive angio-invasive disease of humans caused by Mucorales fungi. Prior to the COVID-19 pandemic, mucormycosis was a rare mycosis typically seen in immunocompromised patients with hematological malignancies or in transplant recipients. During the second wave of the pandemic, there was a dramatic increase in the disease, especially in India where a unique set of circumstances led to large numbers of life-threatening and disfiguring rhino-orbital-cerebral mucormycosis (ROCM) infections.

AREAS COVERED

The review examines mucormycosis as a super-infection of COVID-19 patients, and the risk factors for COVID-19-associated mucormycosis (CAM) that drove the ROCM epidemic in India. The limitations of current diagnostic procedures are identified, and the measures needed to improve the speed and accuracy of detection discussed.

EXPERT OPINION

Despite increased awareness, global healthcare systems remain unprepared for further outbreaks of ROCM. Current diagnosis of the disease is slow and inaccurate, negatively impacting on patient survival. This is most evident in low- to middle-income countries which lack suitably equipped diagnostic facilities for rapid identification of the infecting pathogens. Rapid antigen testing using point-of-care lateral-flow assays could potentially have aided in the quick and accurate diagnosis of the disease, allowing earlier intervention with surgery and Mucorales-active antifungal drugs.

Magnetic resonance imaging in COVID-19-associated acute invasive fungal rhinosinusitis - Diagnosis and beyond

Objectives

The aim of the study was to evaluate the magnetic resonance imaging (MRI) features of acute invasive fungal rhinosinusitis (AIFRS) at presentation and on follow-up imaging when patients receive treatment with systemic antifungal therapy and surgical debridement.

Material and Methods

This is a retrospective analysis of imaging data from a cohort of patients diagnosed with AIFRS during the second wave of COVID-19 in single tertiary referral hospital in South India between March 2021 and May 2021 (n = 68). Final diagnosis was made using a composite reference standard which included a combination of MRI findings, clinical presentation, nasal endoscopy and intraoperative findings, and laboratory proof of invasive fungal infection. Analysis included 62 patients with "Definite AIFRS" findings on MRI and another six patients with "Possible AIFRS" findings on MRI and laboratory proof of invasive fungal infection. Follow-up imaging was available in 41 patients.

Results

The most frequent MRI finding was T2 hypointensity in the sinonasal mucosa (94%) followed by mucosal necrosis/loss of contrast-enhancement (92.6%). Extrasinosal inflammation with or without necrosis in the pre-antral fat, retroantral fat, pterygopalatine fossa, and masticator space was seen in 91.1% of the cases. Extrasinosal spread was identified on MRI even when the computed tomography (CT) showed intact bone with normal extrasinosal density. Orbital involvement (72%) was in the form of contiguous spread from either the ethmoid or maxillary sinuses; the most frequent presentation being orbital cellulitis and necrosis, with some cases showing extension to the orbital apex (41%) and inflammation of the optic nerve (32%). A total of 22 patients showed involvement of the cavernous sinuses out of which 10 had sinus thrombosis and five patients had cavernous internal carotid artery involvement. Intracranial extension was seen both in the form of contiguous spread to the pachymeninges over the frontal and temporal lobes (25%) and intra-axial involvement in the form of cerebritis, abscesses, and infarcts (8.8%). Areas of blooming on SWI were noted within the areas of cerebritis and infarcts. Perineural spread of inflammation was seen along the mandibular nerves across foramen ovale in five patients and from the cisternal segment of trigeminal nerve to the root exit zone in pons in three patients. During follow-up, patients with disease progression showed involvement of the bones of skull base, osteomyelitis of the palate, alveolar process of maxilla, and zygoma. Persistent hyperenhancement in the post-operative bed after surgical debridement and resection was noted even in patients with stable disease.

Conclusion

Contrast-enhanced MRI must be performed in all patients with suspected AIFRS as non-contrast MRI fails to demonstrate tissue necrosis and CT fails to demonstrate extrasinosal disease across intact bony walls. Orbital apex, pterygopalatine fossa, and the cavernous sinuses form important pathways for disease spread to the skull base and intracranial compartment. While cerebritis, intracranial abscesses, and infarcts can be seen early in the disease due to the angioinvasive nature, perineural spread and skull base infiltration are seen 3-4 weeks after disease onset. Exaggerated soft-tissue enhancement in the post-operative bed after debridement can be a normal finding and must not be interpreted as disease progression.

Magnetic Resonance Imaging Features of Rhino-Orbito-Cerebral Mucormycosis in Post-COVID-19 Patients: Radio-Pathological Correlation

There has been a notable increase in rhino-orbito-cerebral mucormycosis (ROCM) post-coronavirus disease 2019 (COVID-19), which is an invasive fungal infection with a fatal outcome. Magnetic resonance imaging (MRI) is a valuable tool for early diagnosis of ROCM and assists in the proper management of these cases. This study aimed to describe the characteristic MRI findings of ROCM in post-COVID-19 patients to help in the early diagnosis and management of these patients. This retrospective descriptive study was conducted at a single hospital and included 52 patients with COVID-19 and a histopathologically proven ROCM infection who were referred for an MRI of the paranasal sinuses (PNS) due to sino-orbital manifestations. Two radiologists reviewed all the MR images in consensus. The diagnosis was confirmed by histopathological examination. The maxillary sinus was the most commonly affected PNS (96.2%). In most patients (57.7%), multiple sinuses were involved with the black turbinate sign on postcontrast images. Extrasinus was evident in 43 patients with orbital involvement. The pterygopalatine fossa was involved in four patients. Three patients had cavernous sinus extension, two had pachymeningeal enhancement, and one had epidural collection. The alveolar margin was affected in two patients, and five patients had an extension to the cheek. The awareness of radiologists by the characteristic MRI features of ROCM in post-COVID-19 patients helps in early detection, early proper management, and prevention of morbid complications.

COVID-Associated Sinonasal Mucormycosis: Radiological Pathological Correlation and Prognostic Value of MR Imaging

Purpose  Our aim was to assess the sinonasal magnetic resonance imaging (MRI) features of acute invasive fungal rhinosinusitis (AIFRS) in coronavirus disease (COVID)-associated mucormycosis (CAM) and to correlate these with histopathology and patient outcome in terms of duration of hospital stay and survival at 10 weeks. Methods  Twenty patients with histopathologically confirmed sinonasal CAM underwent MRI (including postcontrast T1-weighted and diffusion-weighted imaging). Histopathological findings (presence of coagulative necrosis, granulomatous reaction, and fungal burden) were recorded and all patients were followed up at 6 and 10 weeks. Statistical analysis was done using chi-square test and Fischer's exact test. Results  Enhancement patterns seen in our subjects included homogeneous, heterogeneous, and lack of contrast enhancement (LOC), with LOC being the most common (65%). Diffusion restriction was found in 90% patients. Statistically significant correlation was found between LOC pattern and presence of coagulative necrosis ( p -value = 0.007), extent of fungal hyphae ( p -value = 0.047), and duration of hospital stay ( p -value = 0.004). Restricted diffusion was also seen to correlate with a high fungal load ( p -value = 0.007). Conclusion  Our study describes the MRI findings of AIFRS in CAM and highlights the imaging features which may be surrogate markers for coagulative necrosis and fungal burden.

Imaging of COVID-19-associated rhino-orbital-cerebral mucormycosis: imaging analysis of 120 patients

Background

With the ongoing pandemic of COVID-19, there has been a rapid upsurge in cases of rhino-orbital-cerebral mucormycosis (ROCM). It is an opportunistic fungal infection associated with high morbidity and mortality. Rapid and appropriate application of clinical and radiological methods is crucial for early diagnosis, to limit the associated morbidity and improve post-treatment outcomes. In our study, we analyzed imaging features, common sites, and the extent of infection in patients suffering from ROCM.

Results

The majority of the patients were either diabetics or developed uncontrolled blood glucose levels during COVID-19 infection. 79.17% of patients had a history of treatment with steroid therapy. Headache and facial pain were the most common clinical features seen in 76.67% and 60% of patients, respectively. Maxillary and ethmoid sinuses were commonly involved. The most common extra-sinus site of involvement was periantral fat and orbit, seen in 91 (75.83%) and 84 (70%) patients, respectively. Bone erosion or marrow edema was seen in 72 (60%) patients. Intracranial extension in the form of meningitis, cavernous sinus thrombophlebitis/thrombosis, and brain abscess were seen in 20%, 10%, and 3.3% of patients, respectively. MRI-based staging showed that 24.7% of patients had stage I, 5.83% had stage II, 50% had stage III, and 20% had stage IV disease.

Conclusion

The spread of COVID-19-associated rhinomucormycosis to extra-sinus sites is common, which can be detected adequately on MRI. The radiological signs of invasion and devitalization of tissues are crucial for the early diagnosis of ROCM.

A pictorial review of imaging manifestations of rhino-orbito-cerebral mucormycosis–emerging threat in COVID pandemic

Mucormycosis is an aggressive invasive fungal infection caused by mycocetes fungi. It is an opportunistic infection, associated with high morbidity and mortality. In the current era of COVID-19 pandemic, the entire world has witnessed a dramatic upsurge in cases of Mucormycosis. Paranasal sinuses are the commonest site to be affected with the tendency for rapid spread to orbit, face, and brain. Early diagnosis and prompt medical or surgical intervention are the only ways for preventing morbidity and saving precious lives. Imaging plays a crucial role not only in diagnosis but also in defining the extent of the disease for presurgical mapping. Black turbinate sign in the nasal cavity, mucosal thickening in paranasal sinuses with periantral invasion, and bony erosion are the early diagnostic signs. This pictorial review shall provide a comprehensive review of the various imaging manifestations of rhino-orbito-cerebral mucormycosis with a final proposed reporting checklist.

Neuroimaging Findings in COVID-19 Associated Rhino-Orbital-Cerebral Mucormycosis: A Review

The involvement of the neurological system by coronavirus has been well established. Since its onset, the systemic manifestations of coronavirus disease 2019 (COVID-19) have been evolving rapidly and imaging plays a pivotal role in diagnosing the various primary and secondary effects of the disease. As the pandemic continues to defy human civilization, secondary impacts of the disease and the treatment given to patients afflicted with the disease have stemmed up. Rhino-orbital-cerebral mucormycosis is one such potentially dangerous infection now commonly seen in COVID-19 patients, especially the ones treated with immunosuppressants. Early diagnosis is key for COVID-19-associated mucormycosis (CAM), and radiologists should be well aware of its alarming neurological manifestations from the involvement of parenchyma, meninges, vessels, cranial nerves, and skull base. This review highlights the magnetic resonance imaging features of neuraxial involvement in CAM.

Magnetic resonance imaging in rhino-orbital-cerebral mucormycosis

Coronavirus disease-associated mucormycosis (CAM) is an established clinical entity in India. In the past 4 months, there has been a sharp upsurge in the number of CAM cases in most parts of the country. Early diagnosis can be lifesaving. Magnetic resonance imaging (MRI) imaging remains the corner stone of management in patients with ROCM. This review discussed the utility of MRI imaging in ROCM with an emphasis on the ideal MRI protocol in a suspected case of ROCM, the pathways of spread of infection, the classic diagnostic features, MRI for staging of the disease, MRI for prognostication, MRI for follow up, and imaging features of common differentials in ROCM. The pit falls of MRI imaging and a comparison of CT and MRI imaging in ROCM are discussed. The clinical interpretation of areas of contrast uptake and those of necrosis and its relevance to treatment are discussed. This review aims to familiarize every member of the multidisciplinary team involved in managing these patients to be able to interpret the findings on MRI in ROCM.

Rhino-orbital mucormycosis in COVID-19 patients—a new threat?

Background

Coronavirus disease 2019 (COVID-19) is known to be associated with a myriad of viral, fungal, and bacterial co-infections. Rhino-orbital mucormycosis is a rare angio-invasive fungal infection which has shown a rising trend in the setting of COVID-19.

Case presentation

We describe the imaging findings in 3 cases of rhino-orbital mucormycosis in patients with history of COVID-19. All cases had varying involvement of paranasal sinuses extending into the orbital compartment while case 3 had intracranial extension of infection.

Conclusions

Rhino-orbital mucormycosis can have aggressive necrosis of the involved paranasal sinuses and orbits with or without cerebral extension. Hence, the correct diagnosis is imperative as prompt antifungal drugs and surgical debridement can significantly reduce mortality and morbidity.