Quantitative Analysis of the Olfactory System in COVID-19: An MR Imaging Study.

BACKGROUND AND PURPOSE: Anosmia or hyposmia, often accompanied by changes in taste, is recognized as a common symptom that can assist in the diagnosis of coronavirus disease 2019 (COVID-19). The pathogenesis of olfactory dysfunction in COVID-19 is not yet fully understood. MR imaging represents a useful anatomic imaging method for the evaluation of olfactory dysfunction associated with varying etiologies, including viral infection, trauma, and neurodegenerative processes. This case-control study was conducted to compare quantitative measurements of olfactory anatomic structures between patients diagnosed with COVID-19 associated with persistent olfactory dysfunction and healthy controls. MATERIALS AND METHODS: This study has a retrospective design. Cranial MR imaging was performed on all participants in both the patient and control groups. The bilateral olfactory bulb volume, olfactory tract length, and olfactory sulcus depth were measured in all patients. RESULTS: A total of 116 people aged 18-60 years, including 36 patients diagnosed with COVID-19 and 80 controls, were included in the study. All measured values were compared between the patient and control groups. The right, left, and total olfactory bulb volume values were significantly lower in the patient group than in the control group. The patient group also had significantly lower right and left olfactory sulcus depth and olfactory tract length values compared with those in the control group. CONCLUSIONS: MR imaging findings can be used to demonstrate olfactory injury in patients with COVID-19. The olfactory pathway may represent an alternative route for virus entry into the central nervous system.

Neurological symptoms in COVID-19 patients.

OBJECTIVES: Our study aimed to investigate neurological symptoms in patients with COVID-19 and contribute to this area of limited knowledge. BACKGROUND: Increasing evidence shows that neurotropism is a common feature of Coronaviruses (CoVs). Like the other CoVs, SARS-CoV 2 uses angiotensin-converting enzyme 2 (ACE2). The brain is thought to express ACE2 receptors detected on glial cells and neurons. There are also ACE2 receptors in skeletal muscles. Our study aimed to investigate neurological symptoms in patients with COVID-19 and contribute to this area of limited knowledge. METHODS: A total of 51 patients, presented to hospitalized in our hospital between March 23, 2020 and April 16, 2020 were included in the study. The diagnosis of all patients included in the study was made according to the WHO interim guideline. The patients were divided into two subgroups as mild and severe course according to the severity of the disease. RESULTS: Neurological symptoms were detected in 16 (31.37 %) patients. Muscle injury was detected in 10 (19.61 %) patients. The most common neurological symptom was headache (n: 9, 17.65 %). When the frequency of all neurological symptoms was compared in those with severe and mild disease, no significant differences were found between the groups. When the frequency of muscular involvement was compared in patients with severe and mild course, no significant differences were found between the groups. CONCLUSION: The nervous system and skeletal muscle system may be among viral targets. Detection of some neurological findings may be valuable in predicting the course of the disease. Some laboratory values can allow predicting disease severity and neurological symptoms (Tab. 5, Ref. 23) Keywords: COVID-19, neurotropism, muscle injury, headache.

Quantitative analysis of healthy olfactory sulcus depth, olfactory tract length and olfactory bulb volume in the paediatric population: a magnetic resonance study.

BACKGROUND: The aim of this study was to determine the normal reference values for olfactory sulcus depth, olfactory tract length and olfactory bulb volume in the paediatric population with routine magnetic resonance imaging (MRI) and determine the relationship, if any, between these values and patient sex and age. MATERIALS AND METHODS: Ninety patients with a median age of 8 years (age range: 3-17 years), consisting of 45 males and 45 females with normal brain MRI scans were evaluated. The patients were divided into three subgroups based on age range, with n = 30 per subgroup; group 1: young children (3-6 years), group 2: children (7-11 years) and group 3: adolescents (12-17 years). In the cranial MRI examination of all groups, the right, left and total olfactory bulb volume values were measured in mm3, the right and left olfactory tract length values and the right and left olfactory sulcus depth values were calculated manually in mm. Demographic data including sex and age were recorded. RESULTS: There was no significant difference between the age groups in terms of sex. Right-left olfactory sulcus depth; right-left olfactory tract length and right-left total olfactory bulb volume values increased significantly when they are compared in terms of age groups (p < 0.0001, = 0.028; < 0.0001, < 0.0001; < 0.0001, < 0.0001; < 0.0001, respectively). There was no significant difference between right and left olfactory tract length and olfactory bulb volumes in all groups (p = 0.792 and p = 0.478), but the right olfactory sulcus depth was significantly larger than the left (p = 0.003). CONCLUSIONS: Especially as the age progresses, olfactory tract length and olfactory bulb volume dimensions of olfactory nerve and olfactory sulcus depth should be checked during diagnosis of respective illnesses in paediatric population.