A model for classification of invasive fungal rhinosinusitis by computed tomography

Abstract

Our purpose was to classify acute invasive fungal rhinosinusitis (AIFR) caused by Mucor versus Aspergillus species by evaluating computed tomography radiological findings. Two blinded readers retrospectively graded radiological abnormalities of the craniofacial region observed on craniofacial CT examinations obtained during initial evaluation of 38 patients with eventually pathology-proven AIFR (13:25, Mucor:Aspergillus). Binomial logistic regression was used to analyze correlation between variables and type of fungi. Score-based models were implemented for analyzing differences in laterality of findings, including the 'unilateral presence' and 'bilateral mean' models. Binary logistic regression was used, with Score as the only predictor and Group (Mucor vs Aspergillus) as the only outcome. Specificity, sensitivity, positive predictive value, negative predictive value and accuracy were determined for the evaluated models. Given the low predictive value of any single evaluated anatomical site, a 'bilateral mean' score-based model including the nasal cavity, maxillary sinuses, ethmoid air cells, sphenoid sinus and frontal sinuses yielded the highest prediction accuracy, with Mucor induced AIFR correlating with higher prevalence of bilateral findings. The odds ratio for the model while integrating the above anatomical sites was 12.3 (p < 0.001). PPV, NPV, sensitivity, specificity and accuracy were 0.85, 0.82, 0.92, 0.69 and 0.84 respectively. The abnormal radiological findings on craniofacial CT scans of Mucor and Aspergillus induced AIFR could be differentiated based on laterality, with Mucor induced AIFR associated with higher prevalence of bilateral findings. Acute invasive fungal rhinosinusitis (AIFR) is a rapidly progressive and life-threatening infection involving the nasal cavity and paranasal sinuses 1-3. Patients with early stage AIFR limited to the nasal cavity and paranasal sinuses, have relatively lower mortality rates 2 , while intracranial extension doubles the mortality 4. While a variety of causative organisms have been identified, Aspergillus and Mucor fungal species are predominant 3. The most commonly predisposing conditions involve immunodeficiency and include hematologic malignancies, poorly controlled diabetes mellitus, chemotherapy or immunosuppression due to hematopoietic stem cells or organ transplantation 5,6. Even though AIFR is a rare disease, its high mortality rate of approximately 50% 7 highlights the importance of an appropriate and early diagnosis followed by aggressive treatment utilizing a combination of surgical debridement, antifungal pharmacotherapy and restoration of the patient's immune system when possible 8. In many cases, AIFR is a manifestation of an overall poor prognosis with mortality attributed to the underlying medical condition 3. Early diagnosis and treatment of AIFR is of paramount importance to reduce patient morbidity and mortality. Effective treatment consists of an early and aggressive debridement of the necrotic tissue to decrease the fungal load and reduce im...

CT Imaging Features in Acute Invasive Fungal Rhinosinusitis- Recalling the Oblivion in the COVID Era

“…In a recent study, it was found that AIFR caused by Aspergillus had predominantly unilateral findings whereas disease due to Mucor species, the species most often associated with CAM, had greater bilateral sinonasal involvement. 4 …”

“… 3 The recent COVID 19 pandemic has witnessed a high surge in cases of AIFR especially of the Mucor species, which was the less common cause of AIFR in the pre covid era, second to Aspergillus. 4 The Indian subcontinent witnessed a dramatic spurt in cases of COVID associated mucormycosis (CAM) and by June 7, 2021, a spate of 28,252 cases of mucormycosis were reported, 86% having a history of COVID-19 infection. 5 , 6…”

Revisiting rhino-orbito-cerebral acute invasive fungal sinusitis in the era of COVID-19: pictorial review

“…Aspergillus has a tendency towards unilateral involvement (Fig. 12 ) compared to Mucor [ 13 ]. Mucor , however, has a marked tendency to cause invasive thrombosis of vessel walls and the characteristic “black turbinate sign” (non-enhancement of nasal mucosa or turbinates on CECT/CEMRI) [ 14 ].…”

The Integral Role of Radiology in the Diagnosis and Management of COVID-19–Associated Mucormycosis Infections

“…Aspergillosis more commonly has sinocranial involvement in the absence of orbital involvement, dural-based T2 hypointense masses on MRI, and unilateral (versus bilateral in mucormycosis) sinonasal cavity involvement. 7 On the other hand, thrombosis due to the involvement of vessel walls and a black turbinate sign are more common in mucormycosis infection. 4 Recent case series have been published describing the imaging findings of COVID-19-associated rhino-oculo-cerebral mucormycosis.…”