{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T14:49:56Z","timestamp":1786978196693,"version":"build-2736575974"},"reference-count":36,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,16]],"date-time":"2026-08-16T00:00:00Z","timestamp":1786838400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ondokuz May\u0131s University Project Management Office, Samsun, T\u00fcrkiye","award":["PYO.TIP.1901.22.005"],"award-info":[{"award-number":["PYO.TIP.1901.22.005"]}]},{"award":["PYO.TIP.1901.22.005"],"award-info":[{"award-number":["PYO.TIP.1901.22.005"]}],"id":[{"id":"https:\/\/ror.org\/028k5qw24","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>COVID-19 affects the olfactory system and the hippocampus, leading to severe olfactory and cognitive impairments. This study aimed to quantify volumetric changes in the olfactory bulbs and hippocampus in patients with COVID-19, and to investigate these differences in relation to loss of smell and taste. This stereological MRI study included 60 COVID-19 (+) participants and 54 non-COVID-19 participants. Using OsiriX software, the volumes of the olfactory bulb and hippocampus were manually measured from 3T MRI images. Compared with controls, participants with loss of smell and taste had smaller olfactory bulb volumes. This decrease was especially noticeable in the left olfactory bulb of female patients. Furthermore, the right hippocampal volume in male patients with loss of smell and taste was significantly decreased. These findings suggest that atrophy of the olfactory bulb and hippocampus may be specific to certain regions and sexes following SARS-CoV-2 infection. Stereological MRI assessments can effectively identify these changes. Prospective longitudinal studies are needed to determine the clinical significance of these changes and their impact on patient management.<\/jats:p>","DOI":"10.3390\/v18080902","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T13:42:17Z","timestamp":1786974137000},"page":"902","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Possible Volumetric Changes in the Hippocampus and Olfactory Bulbs After COVID-19: A Stereological MRI Study"],"prefix":"10.3390","volume":"18","author":[{"given":"Gamze","family":"Altun","sequence":"first","affiliation":[{"name":"Department of Histology and Embryology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aynur","family":"Atilla","sequence":"additional","affiliation":[{"name":"Department of Infection Diseases, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kerim","family":"Aslan","sequence":"additional","affiliation":[{"name":"Department of Radiology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K\u0131ymet K\u00fcbra","family":"T\u00fcfekci","sequence":"additional","affiliation":[{"name":"Department of Histology and Embryology, Faculty of Medicine, Kastamonu University, 37150 Kastamonu, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bar\u0131\u015f","family":"Gen\u00e7","sequence":"additional","affiliation":[{"name":"Department of Radiology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6984-3079","authenticated-orcid":false,"given":"Arife Ahsen","family":"Kaplan","sequence":"additional","affiliation":[{"name":"Department of Histology and Embryology, Faculty of Medicine, Bolu Abant \u0130zzet Baysal University, 14030 Bolu, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00d6zg\u00fcr","family":"Kemal","sequence":"additional","affiliation":[{"name":"Department of Otolaryngology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Murat","family":"Terzi","sequence":"additional","affiliation":[{"name":"Department of Neurology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6127-8645","authenticated-orcid":false,"given":"H\u00fcseyin","family":"Akan","sequence":"additional","affiliation":[{"name":"Department of Radiology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1477-5002","authenticated-orcid":false,"given":"S\u00fcleyman","family":"Kaplan","sequence":"additional","affiliation":[{"name":"Department of Histology and Embryology, Faculty of Medicine, Ondokuz May\u0131s University, 55139 Samsun, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,16]]},"reference":[{"key":"ref_1","first-page":"2","article-title":"Neuropathology of COVID-19 (neuro-COVID): Clinicopathological update","volume":"2","author":"Lou","year":"2021","journal-title":"Free Neuropathol."},{"key":"ref_2","first-page":"20","article-title":"COVID-19 pandemic: From origins to outcomes. 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