Ultrasonographic Imaging of the Fetal Hippocampus

Ultrasonographic Imaging of the Fetal Hippocampus | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Ultrasonographic Imaging of the Fetal Hippocampus Erzat Toprak, Hasan Berkan Sayal This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2838304/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Jun, 2023 Read the published version in Archives of Gynecology and Obstetrics → Version 1 posted 5 You are reading this latest preprint version Abstract Objectives: To investigate whether fetal hippocampus can be visualized in the prenatal examination with two dimentional ultrasound. Methods: This study was designed in cross-section. Healthy singleton pregnant women who applied to the Perinatology outpatient clinic for second-level ultrasound scanning between December 2022 and February 2023 were included in the study. Patients were screened consecutively. Women who have single, healthy pregnancies between 18-24 weeks of gestation were included. Demographic information of the participants was obtained and an ultrasound scan was performed. The fetal fornix - hippocampus' length and height were measured in the sagittal section. Data were presented as mean ± standard deviation, median (min, max), or number (percent). Results: A total of 92 patients were included in the study. Fetal fornix and hippocampus measurements were taken in % 97,8 (90/92) patients. The mean of the fetal fornix – hippocampus length and fetal hippocampus height of 90 patients were measured as 35.6 ± 3.0 and 4.7 ± 3.9, respectively. Conclusion: Fetal fornix and hippocampus can be visualized in easily with two dimentional ultrasound during anomaly scanning in the second trimester. fetal fornix fetal hippocampus second trimester two dimentional ultrasound. Figures Figure 1 Figure 2 Figure 3 What does this study adds to the clinical work? Fetal brain imaging with fetal neurosonography has improved but still needs improvement. Imaging of the fetal hippocampus will further contribute to fetal brain imaging. Introduction The hippocampus is a sea horse–shaped structure situated in the medial portion of the anterior temporal lobe. It bulges laterally into the temporal horn of the lateral ventricle[ 1 ]. The hippocampus plays a major role in memory processing (dorsal hippocampus) and in biological responses to stress (ventral hippocampus)[ 2 , 3 ]. Development of the hippocampal formation has been explained in the literature by diagrams showing progressive infolding of the fetal dentate gyrus, cornu ammonis, subiculum, and parahippocampal gyrus around the progressively smaller hippocampal sulcus (hippocampal fissure)[ 4 – 6 ]. These diagrammatic representations are based on the histologic study reported by Humphrey[ 7 ]. This study provides a developmental basis for the study of hippocampal abnormalities seen with MR imaging. In some cases of agenesis of the corpus callosum, lissencephaly,and holoprosencephaly, the hippocampi have been described as small, unfolded, and vertically oriented. In this study, in several cases of corpus callosal agenesis in which there is a partially unfolded hippocampus and a prominent hippocampal sulcus[ 8 ]. Hippocampal smallness was also found in Down syndrome[ 9 ]. There are limited studies in the literature on ultrasonographic imaging of the fetal hippocampus. In a study by Gindes et al. the reason for the fetal hippocampus and fornix being very close to each other was shown as a C-shaped structure by 3D ultrasonography. Mentioned in this study, the fetal hippocampus was evaluated in a sagittal section[ 10 ]. In our study, we aimed to visualize the fetal fornix and hippocampus in long axis with two-dimensional ultrasonography, Material – methods Study design and patient selection This study was designed as a cross-section. The study was approved by the Ethics Committee of the Karatay University Faculty of Medicine. The sample size of the study was taken from another cross – sectional study by Toprak et al [ 11 ]. Informed consent of all patients was obtained. Single, healthy pregnancies between 18 and 24 weeks of gestation that applied to the Medova Hospital perinatology outpatient clinic for second-level ultrasonography between December 2022 and February 2023 were included in the study. Patients were screened consecutively. Women who have single, healthy pregnancies between 18–24 weeks of gestation were included. Pregnant women who carried a baby with a fetal anomaly, whose used alcohol and / or cigarette smoking, whose had febrile illness, those with a history of psychiatric illness, whose last menstrual date and ultrasonographic measurements were not compatible, who had a baby with fetal growth restriction, who had pregestational diabetes, i.e., type 1 or type 2 diabetes mellitus, diagnosed before pregnancy were excluded. The participants' last menstrual period was confirmed based on an ultrasound recording made before 12 weeks of gestation. The sample size was calculated by determining the total number of patients visiting our center and perinatology clinic and the rate of fetuses with anomalies. Ultrasound Technique Measurements were made with Voluson S8 device (General Electric, Austria, Zipft) with RAB6 / Obstetric probe. All measurements were made by an experienced Maternal Fetal Medicine Specialist (ET, MD). Measurements were made by the same physician twice, at 2 minutes intervals, to evaluate the intrarater reliability. The insonation angle of the ultrasonography probe was made in the fronto-parietal or occipito-parietal direction for proper imaging. After visualizing the thalamus in the fetal brain's sagittal section, the ultrasound probe was angled laterally to view the fetal fornix and hippocampus. In this section, the fetal fornix and hippocampus were viewed as a crescent hyperechogenic borders surrounding the thalamus. The hippocampus follows the fornix distally. Ultrasonographically, it could not be determined optimally in which part of the fornix the tail part of the hippocampus started, but the hippocampus was detected as a wider and heteroechoic structure in the distal fornix. The height of the hippocampus was measured by taking the widest distance between the hyperechogenic lines formed by the choroidal fissure.The trace length feature of the ultrasound device was used for fornix – hippocampus length, and the distance 2 points, on to on method was used for hippocampus height measurement. The fetal fornix - hippocampus' length and height were measured in the sagittal section. The measurements were performed using ultrasonography in the cine mode (Fig. 1 – 3 ). All measurements were made in duplicate, and the average was taken. Statistical analysis All data collected for statistical analysis were analyzed with the Statistical Package for the Social Sciences, version 20, Chicago, IL (SPSS). Data were presented as mean ± standard deviation, median (min, max), or number (percent). Results During this study period, 98 consecutive patients were evaluated. Six patients were excluded from the study due to fetal anomalies and drug use. A total of 92 patients were included in the study. Fetal fornix and hippocampus measurements were taken in % 97,8 (90/92) patients. At the beginning of this study, intra-rater and inter – rater consistency was evaluated in the first 15 patients. Measurements of the fetal fornix-hippocampus take about two minutes. Table 1 shows descriptive data, placental localization, and presentation information for 92 patients. Table 1 Demographic features, placental locations, and fetal presentations of the participant Parameter Value Maternal age, years 28,75 ± 4,8 BMI (kg/m2) 26,7 ± 4,2 Gravity 2 (0, 6) Parity 1 (0, 5) Number of abortions 0,0 (0, 4) Gestational age, week 20,8 ± 2,1 Placental location Anterior 38 (41,3) Posterior 26 (28,3) Fundal 23 (25,0) Lateral 5 (5,4) Fetal presentation Vertex 46 (50,0) Breech 38 (41,3) Transverse 8 (8,7) Data is presented as mean ± standard deviation, median (min, max) or number(%) BMI, body mass index The mean of the fetal fornix – hippocampus length and fetal hippocampus height of 90 patients were measured as 35.6 ± 3.0 and 4.7 ± 3.9, respectively (Table 2 ). Intra-rater consistency was found to be 0.973(excellent agreement) and 0.789 (good agreement) for fornix – hippocampus length and hippocampus height, respectively. Inter-rater consistency was found to be 0.782(good agreement) and 0.696 (moderate agreement) for fornix – hippocampus length and hippocampus height, respectively. Table 2 Fetal hippocampus parameters Insonation direction of the Ultrasound Probe Value Fronto - parietal 57 (62,0) Occiputo - parietal 35 (38,0) Parameter Fetal fornix - hippocampus length, mm 35,6 ± 3,0 Fetal hippocampus height, mm 4,7 ± 3,9 Data is presented as number(%) or mean ± standard deviation. Discussion In our study, fetal fornix and hippocampus length and fetal hippocampus thickness were demonstrated with 2D ultrasound with an imaging rate of 97.8% (90/92) during the second trimester ultrasonographic fetal anomaly scan. In one study, fetal white matter tracts, or fasciculi, were determined with different tissue stains between 13 and 35 weeks of the gestation. The fornix was encircling the thalamus in that study[ 12 ]. The ultrasonographic appearance of the fetal fornix and hippocampus encircling the thalamus in a crescent shape in our study is also consistent with the staining appearances in this study. Gindes et al. stated in their study that the fetal fornix and hippocampus cannot be visualized with 2D ultrasonography. In addition, when the 3D ultrasound images of the aforementioned study are examined, the fetal fornix is shown, but the fetal hippocampus boundaries are not specified [ 10 ]. In our study, the fetal fornix and hippocampus were demonstrated with 2D ultrasonography in the sagittal axis and anterior and posterior steering wheels, with a high success rate within 2 minutes. Thus, fetal fornix and hippocampus length and hippocampus thickness could be measured without the need for 3D ultrasound equipment and experience. Hippocampus height measurement showed the presence of the hippocampus, which is located in the continuation of the fornix. Histopathologically, it has been shown that individuals with Down syndrome have a smaller hippocampus and dentate gyrus anomalies compared to normal individuals [ 9 ]. In the presence of a cortical anomaly detected by MRI in adults, hippocampal atrophy, an abnormally large hippocampus, and hippocampal shape and rotation anomalies were detected. Hippocampal atrophy was found at the highest rate in hemimegalencephaly and schizencephaly cases. An abnormally large hippoccampus was observed in cases of agyria, pachygyria, lissencephaly, and hemimegalencephaly. Hippocampal shape and rotation anomalies were seen in almost all cortical anomalies [ 13 ]. The cases in our study were evaluated, especially considering these anomalies. We did not find any other study in the literature that measured the fetal fornix and hippocampus with 2D ultrasound, except for the study by Gindes et al. with 3D ultrasound. In the aforementioned study, pregnancies between 14 and 37 weeks of gestation were evaluated [ 10 ]. In our study, we included women between 18 and 24 weeks of gestation. This is why the fetal fornix and hippocampus are similar to those of adults after 18 weeks [ 8 ]. Since unilateral fetal fornix and hippocampus measurements were sufficient, we also took unilateral measurements in our study [ 10 ]. In our study, the tail of the fetal hippocampus could not be distinguished from the fornix. The hyperechogenic line formed by the choroidal fissure was used when measuring the hippocampal height. The substructures forming the hippocampus could not be identified. These were considered the disadvantages of our study. In conclusion, the fetal fornix and hippocampus can be visualized quickly and easily with 2D ultrasound during anomaly scanning in the second trimester. Declarations Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Competing Interests The authors have no relevant financial or non-financial interests to disclose. Author Contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [Erzat Toprak] ve [Hasan Berkan Sayal]. The first draft of the manuscript was written by [Erzat Toprak] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Ethics approval This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of University Karatay Consent to participate Informed consent was obtained from all individual participants included in the study. References Felten DL (2006) J.R., Part III: systemic neuroscience. Section C: autonomic, hypothalamic, and limbic systems , in Netter’s Atlas of Human Neuroscience . WB Saunders Co, Philadelphia, pp 106–112 Weinstock M (2008) The long-term behavioural consequences of prenatal stress. Neurosci Biobehavioral Reviews 32(6):1073–1086 Fanselow MS, Dong H-W (2010) Are the dorsal and ventral hippocampus functionally distinct structures? Neuron 65(1):7–19 Baker LL, Barkovich AJ (1992) The large temporal horn: MR analysis in developmental brain anomalies versus hydrocephalus. Am J Neuroradiol 13(1):115–122 Duvernoy HM (2013) The human hippocampus: an atlas of applied anatomy. JF Bergmann-Verlag Sasaki M et al (1993) Hippocampal sulcus remnant: potential cause of change in signal intensity in the hippocampus. Radiology 188(3):743–746 Humphrey T (1967) The development of the human hippocampal fissure. J Anat 101(Pt 4):655 Kier EL et al (1997) Embryology of the human fetal hippocampus: MR imaging, anatomy, and histology. Am J Neuroradiol 18(3):525–532 Sylvester P (1983) The hippocampus in Down's syndrome. J Ment Defic Res 27:227–236 Gindes L et al (2011) Identification of the Fetal Hippocampus and Fornix and Role of 3-Dimensional Sonography. J Ultrasound Med 30(12):1613–1618 Toprak E, Işıkalan MM (2022) Ultrasonographic Imaging of the Fetal Pyloric Sphincter. Journal of Ultrasound in Medicine Horgos B et al (2020) White matter dissection of the fetal brain. Front Neuroanat 14:584266 Montenegro M et al (2006) Patterns of hippocampal abnormalities in malformations of cortical development. J Neurol Neurosurg psychiatry 77(3):367–371 Cite Share Download PDF Status: Published Journal Publication published 09 Jun, 2023 Read the published version in Archives of Gynecology and Obstetrics → Version 1 posted Reviewers agreed at journal 25 Apr, 2023 Reviewers invited by journal 25 Apr, 2023 Editor invited by journal 24 Apr, 2023 Editor assigned by journal 21 Apr, 2023 First submitted to journal 19 Apr, 2023 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2838304","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":195037366,"identity":"ecc070ca-4dad-4da1-b439-cf53a1d65ccb","order_by":0,"name":"Erzat Toprak","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYHADNsbHYJqZuYGw4gMJYC3MxgwMBkAtjMRrYZMGa2EgoIVf+vjDzx9/2OSZtx9Lqy6o+BPN3w7U8qNiG04tkn0JyRIHEtKKZc6kHbs944xB7ozDjA2MPWdu49RicIbhAFDL4cQZDOltt3nbDHIbgFqYGdtwa7E/w9j8A6yF/3lbMUjLfEJaDHiY2SC2SKQdYwZp2UBIi8QZNjaLM2lpxRISz5Klec4Y524EajmIzy/8PeyPb1TY2ORJ8KcZfuapkMudd/7wwQc/KnBrgYEEFN4BguoxtIyCUTAKRsEoQAYAHMdYEK51ZTQAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-2877-1232","institution":"Ministry Health of Turkish Republic Konya City Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Erzat","middleName":"","lastName":"Toprak","suffix":""},{"id":195037367,"identity":"248809c5-798d-4f69-9884-2fd2121717fe","order_by":1,"name":"Hasan Berkan Sayal","email":"","orcid":"","institution":"","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hasan","middleName":"Berkan","lastName":"Sayal","suffix":""}],"badges":[],"createdAt":"2023-04-19 20:23:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2838304/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2838304/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00404-023-07093-7","type":"published","date":"2023-06-09T21:07:42+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":36406263,"identity":"e664f5c3-b363-4878-94a3-bfb44ee3ba58","added_by":"auto","created_at":"2023-04-28 03:55:22","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":687355,"visible":true,"origin":"","legend":"\u003cp\u003eThe fornix and the hippocampus resembles a crescent encircling the thalamus in sagittal section of the fetal hemisphere\u003c/p\u003e\n\u003cp\u003et: thalamus, ol: occipital lobe, oh: occipital horn of the lateral ventricle, tl: temporal lobe, th: temporal horn of the lateral ventricle\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2838304/v1/919266adf6066a17412afdee.jpeg"},{"id":36405870,"identity":"c7c1b668-7cb8-4f63-8a45-daefc791ed2f","added_by":"auto","created_at":"2023-04-28 03:47:22","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":713652,"visible":true,"origin":"","legend":"\u003cp\u003eTrace line between plus marks indicates the fornix and hippocampus length\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2838304/v1/364f2015ca1c33669ea901ae.jpeg"},{"id":36405872,"identity":"7b9be786-e03f-45da-a05f-5bebed1c067b","added_by":"auto","created_at":"2023-04-28 03:47:22","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":709044,"visible":true,"origin":"","legend":"\u003cp\u003eTrace line indicates the hippocampus height\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2838304/v1/21a0e5de94dec05aae1922f5.jpeg"},{"id":44730691,"identity":"b33ce983-ec2e-40e6-8db1-98165dd8c4b3","added_by":"auto","created_at":"2023-10-16 21:33:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":509773,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2838304/v1/8a08f737-d881-448f-a5b9-cfc875004b8e.pdf"}],"financialInterests":"","formattedTitle":"Ultrasonographic Imaging of the Fetal Hippocampus","fulltext":[{"header":"What does this study adds to the clinical work?","content":"\u003cp\u003eFetal brain imaging with fetal neurosonography has improved but still needs improvement. Imaging of the fetal hippocampus will further contribute to fetal brain imaging.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eThe hippocampus is a sea horse\u0026ndash;shaped structure situated in the medial portion of the anterior temporal lobe. It bulges laterally into the temporal horn of the lateral ventricle[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The hippocampus plays a major role in memory processing (dorsal hippocampus) and in biological responses to stress (ventral hippocampus)[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Development of the hippocampal formation has been explained in the literature by diagrams showing progressive infolding of the fetal dentate gyrus, cornu ammonis, subiculum, and parahippocampal gyrus around the progressively smaller hippocampal sulcus (hippocampal fissure)[\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These diagrammatic\u003c/p\u003e \u003cp\u003erepresentations are based on the histologic study reported by Humphrey[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. This study provides a developmental basis for the study of hippocampal abnormalities seen with MR imaging. In some cases of agenesis of the corpus callosum, lissencephaly,and\u003c/p\u003e \u003cp\u003eholoprosencephaly, the hippocampi have been described as small, unfolded, and vertically oriented. In this study, in several cases of corpus callosal agenesis in which there is a partially\u003c/p\u003e \u003cp\u003eunfolded hippocampus and a prominent hippocampal sulcus[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Hippocampal smallness was also found in Down syndrome[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThere are limited studies in the literature on ultrasonographic imaging of the fetal hippocampus. In a study by Gindes et al. the reason for the fetal hippocampus and fornix being very close to each other was shown as a C-shaped structure by 3D ultrasonography. Mentioned in this study, the fetal hippocampus was evaluated in a sagittal section[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our study, we aimed to visualize the fetal fornix and hippocampus in long axis with two-dimensional ultrasonography,\u003c/p\u003e"},{"header":"Material – methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and patient selection\u003c/h2\u003e \u003cp\u003eThis study was designed as a cross-section. The study was approved by the Ethics Committee of the Karatay University Faculty of Medicine. The sample size of the study was taken from another cross \u0026ndash; sectional study by Toprak et al [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eInformed consent\u003c/strong\u003e \u003cp\u003eof all patients was obtained. Single, healthy pregnancies between 18 and 24 weeks of gestation that applied to the Medova Hospital perinatology outpatient clinic for second-level ultrasonography between December 2022 and February 2023 were included in the study. Patients were screened consecutively. Women who have single, healthy pregnancies between 18\u0026ndash;24 weeks of gestation were included. Pregnant women who carried a baby with a fetal anomaly, whose used alcohol and / or cigarette smoking, whose had febrile illness, those with a history of psychiatric illness, whose last menstrual date and ultrasonographic measurements were not compatible, who had a baby with fetal growth restriction, who had pregestational diabetes, i.e., type 1 or type 2 diabetes mellitus, diagnosed before pregnancy were excluded. The participants' last menstrual period was confirmed based on an ultrasound recording made before 12 weeks of gestation. The sample size was calculated by determining the total number of patients visiting our center and perinatology clinic and the rate of fetuses with anomalies.\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eUltrasound Technique\u003c/h2\u003e \u003cp\u003eMeasurements were made with Voluson S8 device (General Electric, Austria, Zipft) with RAB6 / Obstetric probe. All measurements were made by an experienced Maternal Fetal Medicine Specialist (ET, MD). Measurements were made by the same physician twice, at 2 minutes intervals, to evaluate the intrarater reliability. The insonation angle of the ultrasonography probe was made in the fronto-parietal or occipito-parietal direction for proper imaging. After visualizing the thalamus in the fetal brain's sagittal section, the ultrasound probe was angled laterally to view the fetal fornix and hippocampus. In this section, the fetal fornix and hippocampus were viewed as a crescent hyperechogenic borders surrounding the thalamus. The hippocampus follows the fornix distally. Ultrasonographically, it could not be determined optimally in which part of the fornix the tail part of the hippocampus started, but the hippocampus was detected as a wider and heteroechoic structure in the distal fornix. The height of the hippocampus was measured by taking the widest distance between the hyperechogenic lines formed by the choroidal fissure.The trace length feature of the ultrasound device was used for fornix \u0026ndash; hippocampus length, and the distance 2 points, on to on method was used for hippocampus height measurement. The fetal fornix - hippocampus' length and height were measured in the sagittal section. The measurements were performed using ultrasonography in the cine mode (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). All measurements were made in duplicate, and the average was taken.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eAll data collected for statistical analysis were analyzed with the Statistical Package for the Social Sciences, version 20, Chicago, IL (SPSS). Data were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation, median (min, max), or number (percent).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eDuring this study period, 98 consecutive patients were evaluated. Six patients were excluded from the study due to fetal anomalies and drug use. A total of 92 patients were included in the study. Fetal fornix and hippocampus measurements were taken in % 97,8 (90/92) patients. At the beginning of this study, intra-rater and inter \u0026ndash; rater consistency was evaluated in the first 15 patients. Measurements of the fetal fornix-hippocampus take about two minutes. Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e shows descriptive data, placental localization, and presentation information for 92 patients.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eDemographic features, placental locations, and fetal presentations of the participant\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eParameter\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eValue\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMaternal age, years\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e28,75\u0026thinsp;\u0026plusmn;\u0026thinsp;4,8\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBMI (kg/m2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26,7\u0026thinsp;\u0026plusmn;\u0026thinsp;4,2\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eGravity\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2 (0, 6)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eParity\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1 (0, 5)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNumber of abortions\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0,0 (0, 4)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eGestational age, week\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,1\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePlacental location\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eAnterior\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e38 (41,3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePosterior\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26 (28,3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFundal\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e23 (25,0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLateral\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5 (5,4)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eFetal presentation\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eVertex\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e46 (50,0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBreech\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e38 (41,3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTransverse\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8 (8,7)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eData is\u0026nbsp;presented\u0026nbsp;as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation, median (min, max)\u0026nbsp;\u0026nbsp;or number(%)\u003c/p\u003e\n\u003cp\u003eBMI, body mass index\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe mean of the fetal fornix \u0026ndash; hippocampus length and fetal hippocampus height of 90 patients were measured as 35.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0 and 4.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9, respectively (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). Intra-rater consistency was found to be 0.973(excellent agreement) and 0.789 (good agreement) for fornix \u0026ndash; hippocampus length and hippocampus height, respectively. Inter-rater consistency was found to be 0.782(good agreement) and 0.696 (moderate agreement) for fornix \u0026ndash; hippocampus length and hippocampus height, respectively.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eFetal hippocampus parameters\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003cth style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eInsonation direction of the Ultrasound Probe\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eValue\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eFronto - parietal\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003e57 (62,0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eOcciputo - parietal\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003e35 (38,0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eParameter\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eFetal fornix - hippocampus length, mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003e35,6\u0026thinsp;\u0026plusmn;\u0026thinsp;3,0\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003eFetal hippocampus height, mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 35px;\" align=\"left\"\u003e\n\u003cp\u003e4,7\u0026thinsp;\u0026plusmn;\u0026thinsp;3,9\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 35px;\"\u003e\n\u003ctd style=\"height: 35px;\" colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eData is\u0026nbsp;presented\u0026nbsp;as number(%) or mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn our study, fetal fornix and hippocampus length and fetal hippocampus thickness were demonstrated with 2D ultrasound with an imaging rate of 97.8% (90/92) during the second trimester ultrasonographic fetal anomaly scan.\u003c/p\u003e \u003cp\u003eIn one study, fetal white matter tracts, or fasciculi, were determined with different tissue stains between 13 and 35 weeks of the gestation. The fornix was encircling the thalamus in that study[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The ultrasonographic appearance of the fetal fornix and hippocampus encircling the thalamus in a crescent shape in our study is also consistent with the staining appearances in this study.\u003c/p\u003e \u003cp\u003eGindes et al. stated in their study that the fetal fornix and hippocampus cannot be visualized with 2D ultrasonography. In addition, when the 3D ultrasound images of the aforementioned study are examined, the fetal fornix is shown, but the fetal hippocampus boundaries are not specified [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In our study, the fetal fornix and hippocampus were demonstrated with 2D ultrasonography in the sagittal axis and anterior and posterior steering wheels, with a high success rate within 2 minutes. Thus, fetal fornix and hippocampus length and hippocampus thickness could be measured without the need for 3D ultrasound equipment and experience.\u003c/p\u003e \u003cp\u003eHippocampus height measurement showed the presence of the hippocampus, which is located in the continuation of the fornix. Histopathologically, it has been shown that individuals with Down syndrome have a smaller hippocampus and dentate gyrus anomalies compared to normal individuals [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In the presence of a cortical anomaly detected by MRI in adults, hippocampal atrophy, an abnormally large hippocampus, and hippocampal shape and rotation anomalies were detected. Hippocampal atrophy was found at the highest rate in hemimegalencephaly and schizencephaly cases.\u003c/p\u003e \u003cp\u003eAn abnormally large hippoccampus was observed in cases of agyria, pachygyria, lissencephaly, and hemimegalencephaly. Hippocampal shape and rotation anomalies were seen in almost all cortical anomalies [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The cases in our study were evaluated, especially considering these anomalies.\u003c/p\u003e \u003cp\u003eWe did not find any other study in the literature that measured the fetal fornix and hippocampus with 2D ultrasound, except for the study by Gindes et al. with 3D ultrasound. In the aforementioned study, pregnancies between 14 and 37 weeks of gestation were evaluated [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In our study, we included women between 18 and 24 weeks of gestation. This is why the fetal fornix and hippocampus are similar to those of adults after 18 weeks [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Since unilateral fetal fornix and hippocampus measurements were sufficient, we also took unilateral measurements in our study [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our study, the tail of the fetal hippocampus could not be distinguished from the fornix. The hyperechogenic line formed by the choroidal fissure was used when measuring the hippocampal height. The substructures forming the hippocampus could not be identified. These were considered the disadvantages of our study.\u003c/p\u003e \u003cp\u003eIn conclusion, the fetal fornix and hippocampus can be visualized quickly and easily with 2D ultrasound during anomaly scanning in the second trimester.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cem\u003eFunding\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCompeting Interests\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAuthor Contributions\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [Erzat Toprak] ve [Hasan Berkan Sayal]. The first draft of the manuscript was written by [Erzat Toprak] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEthics approval\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThis study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of University Karatay\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConsent to participate\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eInformed consent was obtained from all individual participants included in the study.\u003c/em\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFelten DL (2006) J.R., \u003cem\u003ePart III: systemic neuroscience. Section C: autonomic, hypothalamic, and limbic systems\u003c/em\u003e, in \u003cem\u003eNetter\u0026rsquo;s Atlas of Human Neuroscience\u003c/em\u003e. WB Saunders Co, Philadelphia, pp 106\u0026ndash;112\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeinstock M (2008) The long-term behavioural consequences of prenatal stress. Neurosci Biobehavioral Reviews 32(6):1073\u0026ndash;1086\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFanselow MS, Dong H-W (2010) Are the dorsal and ventral hippocampus functionally distinct structures? Neuron 65(1):7\u0026ndash;19\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaker LL, Barkovich AJ (1992) The large temporal horn: MR analysis in developmental brain anomalies versus hydrocephalus. Am J Neuroradiol 13(1):115\u0026ndash;122\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDuvernoy HM (2013) The human hippocampus: an atlas of applied anatomy. JF Bergmann-Verlag\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSasaki M et al (1993) Hippocampal sulcus remnant: potential cause of change in signal intensity in the hippocampus. Radiology 188(3):743\u0026ndash;746\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHumphrey T (1967) The development of the human hippocampal fissure. J Anat 101(Pt 4):655\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKier EL et al (1997) Embryology of the human fetal hippocampus: MR imaging, anatomy, and histology. Am J Neuroradiol 18(3):525\u0026ndash;532\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSylvester P (1983) The hippocampus in Down's syndrome. J Ment Defic Res 27:227\u0026ndash;236\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGindes L et al (2011) Identification of the Fetal Hippocampus and Fornix and Role of 3-Dimensional Sonography. J Ultrasound Med 30(12):1613\u0026ndash;1618\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eToprak E, Işıkalan MM (2022) Ultrasonographic Imaging of the Fetal Pyloric Sphincter. Journal of Ultrasound in Medicine\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHorgos B et al (2020) White matter dissection of the fetal brain. Front Neuroanat 14:584266\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMontenegro M et al (2006) Patterns of hippocampal abnormalities in malformations of cortical development. J Neurol Neurosurg psychiatry 77(3):367\u0026ndash;371\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"fetal fornix, fetal hippocampus, second trimester, two dimentional ultrasound.","lastPublishedDoi":"10.21203/rs.3.rs-2838304/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2838304/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives: \u003c/strong\u003eTo investigate whether fetal hippocampus can be visualized in the prenatal examination with two dimentional ultrasound.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eThis study was designed in cross-section. Healthy singleton pregnant women who applied to the Perinatology outpatient clinic for second-level ultrasound scanning between December 2022 and February 2023 were included in the study. Patients were screened consecutively. Women who have single, healthy pregnancies between 18-24 weeks of gestation were included. Demographic information of the participants was obtained and an ultrasound scan was performed. The fetal fornix - hippocampus' length and height were measured in the sagittal section. Data were presented as mean ± standard deviation, median (min, max), or number (percent).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e A total of 92 patients were included in the study. Fetal fornix and hippocampus measurements were taken in % 97,8 (90/92) patients. The mean of the fetal fornix – hippocampus length and fetal hippocampus height of 90 patients were measured as 35.6 ± 3.0 and 4.7 ± 3.9, respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e Fetal fornix and hippocampus can be visualized in easily with two dimentional ultrasound during anomaly scanning in the second trimester.\u003c/p\u003e","manuscriptTitle":"Ultrasonographic Imaging of the Fetal Hippocampus","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-04-28 03:47:18","doi":"10.21203/rs.3.rs-2838304/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2023-04-25T16:12:00+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-04-25T15:45:12+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Archives of Gynecology and Obstetrics","date":"2023-04-24T19:27:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-04-21T14:54:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Archives of Gynecology and Obstetrics","date":"2023-04-19T16:23:15+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"b727b2a5-d9a3-4f12-a401-0fb12f49b7a9","owner":[],"postedDate":"April 28th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T21:16:59+00:00","versionOfRecord":{"articleIdentity":"rs-2838304","link":"https://doi.org/10.1007/s00404-023-07093-7","journal":{"identity":"archives-of-gynecology-and-obstetrics","isVorOnly":false,"title":"Archives of Gynecology and Obstetrics"},"publishedOn":"2023-06-09 21:07:42","publishedOnDateReadable":"June 9th, 2023"},"versionCreatedAt":"2023-04-28 03:47:18","video":"","vorDoi":"10.1007/s00404-023-07093-7","vorDoiUrl":"https://doi.org/10.1007/s00404-023-07093-7","workflowStages":[]},"version":"v1","identity":"rs-2838304","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2838304","identity":"rs-2838304","version":["v1"]},"buildId":"-HB7Z8yhvgn0wM9Nzuekk","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}