Differential Diagnosis of Ossified Spinal Meningiomas from Psammomatous Spinal Meningiomas Based on CT and MRI and Surgical Strategy

Differential Diagnosis of Ossified Spinal Meningiomas from Psammomatous Spinal Meningiomas Based on CT and MRI and Surgical Strategy | 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 Differential Diagnosis of Ossified Spinal Meningiomas from Psammomatous Spinal Meningiomas Based on CT and MRI and Surgical Strategy Yiming Ding, Xinyu Song, Xin Liang, Defeng Liu, Longqi Liu, Yibing Su, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9080685/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Introduction: Ossified spinal meningiomas (OSMs) and psammomatous spinal meningiomas (PSMs) each exhibit distinct histological features. Surgical approaches also differ between the two types. Preoperative differentiation between OSMs and PSMs aids in treatment planning. This study aims to distinguish OSMs from PSMs through imaging. Methods Differences between OSMs and PSMs were compared using computed tomography (CT) and magnetic resonance imaging (MRI). The key points of surgery for OSMs were also summarized. Results On the basis of the pathological findings, the patients were divided into OSM and PSM groups. Imaging analysis revealed that the CT signal ratio (2.45) was significantly greater in the OSM group than in the PSM group (0.65), while the T1, T2, and T1 contrast-enhanced signal ratios (0.79, 0.71, and 1.42, respectively) were significantly lower in the OSM group than in the PSM group (1.09, 1.54, and 1.95, respectively; all p values < 0.001). All patients underwent complete tumor resection. Most patients experienced symptomatic improvement after surgery, and no tumor recurrence was observed during follow-up. Conclusion The imaging features differ between OSMs and PSMs. Through specialized surgical approaches and intraoperative neurophysiological monitoring, tumors located on the ventral aspect of the spinal cord can be safely and completely resected. Ossified spinal meningiomas Psammomatous spinal meningiomas Surgical treatment Radiomics Intraoperative neurophysiological neuromonitoring Figures Figure 1 Figure 2 Figure 3 Introduction Spinal meningioma is among the most common primary spinal tumors 1 . The ossifying spinal meningioma (OSM) is a subtype of meningioma characterized by metaplastic ossification 2 , which distinguishes it from the calcification observed in psammomatous spinal meningiomas (PSMs) 3 . On the basis of histological characteristics, both PSMs and OSMs are calcified 4 , but their surgical approaches differ. Ossifying meningiomas pose a challenge for neurosurgeons because partial resection is not feasible 5 . Therefore, it is important to distinguish between OSMs and PSMs before surgery, as this helps determine the treatment plan. For ossifying meningioma, the surgical approach should be expanded to protect nerve function and achieve complete tumor resection. The aim of this study was to distinguish OSMs from PSMs using imaging techniques to guide surgical treatment. Methods Data collection We retrospectively reviewed all spinal meningioma patients who underwent surgery at our hospital from January 2021 to December 2024. The inclusion criteria were as follows: 1) Patients who were newly diagnosed with an ossified meningioma, PSM or calcified meningioma, those who were surgically treated for these tumors, and patients with histologic confirmation of these tumors. 2) Patients who underwent preoperative CT and MRI, including T1, T2 and contrast-enhanced T1. 3) Patients who were followed-up for 3 to 12 months after surgery 4) Patients with available basic information, which included sex, age at surgery, symptoms, signs, and the relationship between the tumor and spinal cord location. All patients provided informed consent before inclusion in the study. Image acquisition The slice thickness for CT scans is 1 millimeter, and MR imaging was performed at 3T. The imaging methods include the T1 inversion recovery sequence, the T2-weighted multispin sequence, and the T1-weighted contrast-enhanced sequence. After the imaging dataset is standardized, tumor characteristics are described using the relative signal ratio. The signal ratio in CT refers to the ratio of tumor signal intensity to that of the vertebral trabecular bone, whereas in MRI, the signal ratio denotes the ratio of tumor signal intensity to that of normal spinal cord tissue. After each sequence was repeated three times, the average value was taken. Surgical management The patient was placed in a prone position under general anesthesia. After preoperative localization using a C-arm machine, a laminectomy was performed at one or more segments based on the extent and location of the tumor to further expose the dura mater. Different surgical strategies were adopted according to the specific positional relationship between the tumor and the spinal cord: ① For tumors located dorsally or laterally to the spinal cord, the dura was incised along the midline, and the tumor was carefully resected en bloc. ② For tumors located ventrally to the spinal cord, the resection range of the ipsilateral pedicle was appropriately expanded, and the surgical table was tilted to facilitate tumor removal from a slightly lateral approach relative to the spinal cord. Following complete tumor resection and confirmation of no active bleeding, the dura was closed with sutures. No internal spinal fixation was performed during the procedure. Intraoperative electrophysiological monitoring (neuromonitoring) was performed throughout the surgery to ensure neurological safety. Intraoperative neurophysiological neuromonitoring Intraoperative electrophysiological monitoring of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) was performed. After successful anesthesia, electrodes were placed, and no muscle relaxants were used during surgery to ensure accurate monitoring. Transcutaneous electrical stimulation was applied before and after laminectomy, before and after the dura mater incision, before and after tumor resection, and after dura mater closure to monitor whether surgical manipulation caused nerve damage. Spontaneous electrical activity in muscles and other tissues generates free-running signals. When evoked potentials are monitored, the integrity of the nervous system can be assessed by applying stimuli of known intensity, duration, and frequency at one end of the neural pathway and by measuring the response in volts at the other end. The alarm criteria were a decrease in amplitude exceeding 50% of the baseline or a prolongation of the latency exceeding 10% of the baseline 6 . When an alarm occurred, surgical manipulation was immediately stopped, the area was left undisturbed for several minutes to identify the cause, and to prevent nerve injury, surgery was resumed only after the patient’s electromyographic response had recovered. Statistical analysis SPSS version 25.0 (IBM Corp., Armonk, New York, USA) was used for statistical analyses. The normal distribution was checked with the Shapiro–Wilk test. Independent samples t tests were used to compare the CT and MRI signal ratios between the OSM and the PSM groups. Chi-square tests were used to compare sex and age between the OSM and PSM, respectively groups. P < 0.05 indicated statistical significance. Results Clinical results In this study, data were collected from 48 patients who were diagnosed with gritty meningioma, calcified meningioma, or ossifying meningioma (41 women and 7 men; mean age: 61.0 ± 11.8 years; age range: 24–79 years). Fifteen patients experienced pain symptoms, 31 patients experienced numbness, 21 patients exhibited decreased muscle strength, 5 patients had diminished pain and temperature sensation, and 17 patients reported subjective limb weakness. MRI findings Patients with a pathological diagnosis of ossified meningioma and those with bone components within the tumor tissue were assigned to the OSM group(Figure-1). Patients with a pathological diagnosis of psammomatous or calcified meningioma were assigned to the PSM group. The CT signal ratio in the OSM group (mean 2.45) was significantly greater than that in the PSM group (mean 0.65) (p < 0.001). The T1 signal ratio in the OSM group (mean 0.79) was lower than that in the PSM group (mean 1.09) (p < 0.001). The T2 signal ratio in the OSM group (mean 0.71) was significantly lower than that in the PSM group (mean 1.54) (p < 0.001). The T1 contrast-enhanced signal ratio in the OSM group (mean 0.1.42) was lower than that in the PSM group (mean 1.95) (p < 0.001) ༈Figure-2, Table-1༉. Outcome All patients underwent microsurgical subdural tumor resection via the posterior median approach under electrophysiological monitoring, with complete tumor resection achieved in all patients. Pain relief was achieved in 8 patients, numbness resolution was achieved in 33 patients, and weakness was improved in 4 patients. Sensory loss (pain and temperature) resolved in 3 patients, muscle strength recovered in 10 patients with prior weakness, and muscle strength decreased in 3 patients. All patients were followed-up for 3–12 months after surgery in an outpatient setting. Follow-up MRI scans revealed no tumor recurrence. Discussion Meningiomas account for approximately 25–30% of all spinal cord tumors 7 . Women are at a significantly greater risk for the development of spinal meningiomas than are men 8 . Spinal meningiomas are most commonly found in elderly women, and their peak incidence occurs at approximately age 70 years 9 . Ossified meningiomas (OSMs) are extremely rare and account for approximately 1% of all meningiomas 10 . Ossified meningiomas are considered to evolve from calcified meningiomas. Calcification in meningiomas is secondary to the metaplasia of arachnoid cells and not to psammomatous features 4 . Due to the limited space within the spinal canal, symptoms typically manifest rapidly on the basis of the texture and structure of the OSM 5 . Due to its hard-rock texture and extensive adhesion to surrounding critical spinal cord structures, surgical treatment of OSM is highly complex and may affect patient prognosis 11 . As a result of differences in signal intensity between calcification and ossification, the two can be distinguished on imaging. To date, no systematic comparison of the imaging characteristics of these two tumors has been conducted. For calcified meningiomas, CT scans may occasionally reveal distinct nodular and layered areas of high signal intensity, whereas MRI images typically lack such prominent features 12 . Among 11 patients with pathologically confirmed PSMs, 10 exhibited significant calcification on CT scans 13 . Ossifying meningioma presents as a dense lesion on CT and has low signal intensity on T2-weighted imaging (T2WI) 14 . Ossifying meningioma appears as a high-density lesion on CT scans and demonstrates low signal intensity on T2-weighted images 15 , 16 . These reports are consistent with the findings of this study. The results of this study indicate that the CT scan density values of the OSM group are more than twice those of the PSM group. In T2-weighted MR images, the signal intensity of OSM was significantly lower than that of PSM. Therefore, preoperative radiomics analysis can distinguish between OSM and PSM, a method that can help guide surgical planning.Calcified meningiomas and ossifying meningiomas are more readily identified by CT 4 . Surgery is the preferred treatment for OSM, and because partial resection is not feasible (video 1), complete resection is the only option(video 2), and thus OSM is a persistent challenge for surgeons. Many authors believe that the posterior midline approach, through extensive resection of the lamina and pedicles extending to the posterior aspect of the vertebral body, provides adequate tumor exposure, thereby offering a lateral access pathway for tumor resection 17 . In the surgical approach described by Jitendra et al., the extension of unilateral hemilaminectomy into the medial region of the pedicle not only alleviated postoperative pain and discomfort but also maintained spinal stability and promoted early rehabilitation 18 . Regardless of the surgical approach, the goal is to avoid manipulation of the spinal cord, as even the slightest traction or compression may lead to a worsened prognosis 19 . Therefore, the management of intraoperative OSM becomes critically important. Some authors recommend the use of high-speed diamond drill bits in conjunction with ultrasonic surgical aspirators to achieve safe and effective tumor resection while avoiding spinal cord stimulation 20 . However, we believe that this approach is associated with a risk of neurovascular injury; thus, we advocate the use of a wider surgical approach to remove the tumor. When the tumor is located on the ventral side of the spinal cord, we believe that it is necessary to appropriately expand the resection of the ipsilateral lamina, retract the dura mater ipsilaterally (or perform a T-shaped incision of the dura mater), and adjust the operating table angle to resect the tumor from a more lateral-to-medial approach relative to the spinal cord (Figure-3). Electrophysiological monitoring was performed throughout the entire surgical procedure to ensure the maintenance of neural function. Conclusion An OSM is a rare type of meningioma that is distinct from a PSM. Surgical resection of ossified meningioma is challenging, and thus preoperative imaging assessment is crucial for guiding the surgical strategy. Tumors located on the ventral aspect of the spinal cord can be safely and completely resected through specialized surgical approaches and intraoperative neurophysiological neuromonitoring. Abbreviations Ossified spinal meningiomas OSMs Psammomatous spinal meningiomas PSMs computed tomography CT magnetic resonance imaging MRI somatosensory evoked potentials SEPs motor evoked potentials MEPs Declarations Consent for publication All authors of this manuscript consent to participate. Availability of data and materials Not applicable. Authors' contributions The corresponding author, Liang Shi, provided overall supervision, secured funding, coordinated the project, and critically reviewed and finalized the manuscript. Yiming Ding contributed to the study conception and design, data acquisition, interpretation of results, and drafting of the manuscript. Xinyu Song was responsible for clinical data collection, figure preparation. Xin Liang assisted with study design and ethical oversight, Defeng Liu contributed to statistical analysis, Longqi Liu provided data validation and participated in manuscript revision, Yibing Su contributed to data interpretation and clinical expertise. All authors reviewed the manuscript, approved its final version, and agree to be accountable for all aspects of the work. Acknowledgements Not applicable. Funding The study was supported by This work was supported by Beijing Municipal Administration of Hospitals Incubating Program (PX2020018), Beijing Jishuitan Hospital Elite Young Scholar Programme (XKGG202115), Beijing Jishuitan Research Funding，Beijing Jishuitan Hospital, Capital Medical University (ZR-202510), Beijing Jishuitan Research Funding，Beijing Jishuitan Hospital, Capital Medical University（QN-202503） Declaration of Competing Interest The authors declare that they have no competing interests. Ethics Approval declaration Ethical approval All procedures performed in studies involving human participants were conducted in accordance with the ethical standards of Beijing Jishuitan Hospital, Capital Medical University[Ethics Committee of Beijing Jishuitan Hospital: K2023-144-00], and with the1964 Helsinki Declaration and its later amendments or comparable ethical standards. Human Ethics and Consent to Participate declarations All studies obtained informed consent from participants. The patients provided their written informed consent to participate in this study. Written informed consent was obtained from the individuals for the publication of any potentially identifiable images or data included in this article References Ravindra VM, Schmidt MH. Spinal Meningiomas: Diagnosis, Surgical Management, and Adjuvant Therapies. Neurosurgery clinics of North America. 2023;34(3):425-435. Kitagawa M, Nakamura T, Aida T. Clinicopathologic analysis of ossification in spinal meningioma. Article in Japanese. 1994;11(1):115-119. Yamane K, Tanaka M, Sugimoto Y. Spinal metaplastic meningioma with osseous differentiation in the ventral thoracic spinal canal. 2014;68(5):313-316. Ruggeri AG, Fazzolari B, Colistra D, Cappelletti M, Marotta N, Delfini R. Calcified Spinal Meningiomas. World neurosurgery. 2017;102:406-412. Alafaci C, Grasso G, Granata F, Salpietro FM, Tomasello F. Ossified spinal meningiomas: Clinical and surgical features. Clinical neurology and neurosurgery. 2016;142:93-97. Adkins GB, Mirallave Pescador A, Koht AH, Gosavi SP. Intraoperative neuromonitoring in intracranial surgery. BJA education. 2024;24(5):173-182. Corell A, Cerbach C, Hoefling N, Björkman-Burtscher IM, Jakola AS. Spinal cord compression in relation to clinical symptoms in patients with spinal meningiomas. Clinical neurology and neurosurgery. 2021;211:107018. DiGiorgio AM, Virk MS, Mummaneni PV. Spinal meningiomas. Handbook of clinical neurology. 2020;170:251-256. Dang DD, Mugge LA, Awan OK, Gong AD, Fanous AA. Spinal Meningiomas: A Comprehensive Review and Update on Advancements in Molecular Characterization, Diagnostics, Surgical Approach and Technology, and Alternative Therapies. 2024;16(7):1426. Barresi V, Caffo M, Ieni A, Alafaci C, Tuccari G. Osteoblastic meningiomas: clinico-pathological and immunohistochemical features of an uncommon variant. Journal of neuro-oncology. 2011;105(2):225-232. Caffo M, Caruso G, Barresi V, Tomasello F. Ossified Intracranial Meningiomas: Description of the First Series of Cases and Review of the Literature. World neurosurgery. 2016;94:458-464. Zhu Q, Qian M, Xiao J, Wu Z, Wang Y, Zhang J. Myelopathy due to calcified meningiomas of the thoracic spine: minimum 3-year follow-up after surgical treatment. Journal of neurosurgery Spine. 2013;18(5):436-442. Lee JW, Lee IS, Choi KU, et al. CT and MRI findings of calcified spinal meningiomas: correlation with pathological findings. Skeletal radiology. 2010;39(4):345-352. Aljalal NS, Alshoabi SA. Paraplegia as a Severe Presentation of an Unusual Form of Ossified Intradural Meningioma: Case Report. SN Comprehensive Clinical Medicine. 2020;2(10):1906-1909. Taha MM, Alawamry A, Abdel-Aziz HR. Ossified Spinal Meningioma: A Case Report and a Review of the Literature. Surgery journal (New York, NY). 2019;5(4):e137-e141. Murakami T, Tanishima S, Takeda C, Kato S, Nagashima H. Ossified Metaplastic Spinal Meningioma Without Psammomatous Calcification: A Case Report. Yonago acta medica. 2019;62(2):232-235. Freidberg S. Removal of an ossified ventral thoracic meningioma. Case report. 1972;37(6):728-730. Thakur J, Ulrich CT, Schär RT, Seidel K, Raabe A, Jesse CM. The surgical challenge of ossified ventrolateral spinal meningiomas: tricks and pearls for managing large ossified meningiomas of the thoracic spine. Journal of neurosurgery Spine. 2021;35(4):516-526. Chotai S, Mrak R, Mutgi S, Medhkour A. Ossification in an extra-intradural spinal meningioma-pathologic and surgical vistas. 2013;13(12):e21-e26. Cochran E, Schlauderaff A, Rand S. Spinal osteoblastic meningioma with hematopoiesis: radiologic-pathologic correlation and review of the literature. 2016;24:30-34. Table Table1. Details of signal ratio in CT and MRI. OSM PSM P-value Mean of CT-signal ratio 2.45 0.65 ＜0.0001 Mean of T1-signal ratio 0.79 1.09 0.0042 Mean of T2-signal ratio 0.71 1.53 0.0378 Mean of Tce-signal ratio 1.42 1.95 0.0425 Additional Declarations No competing interests reported. Supplementary Files video1.mp4 video2.mp4 Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 04 Apr, 2026 Reviewers agreed at journal 04 Apr, 2026 Reviewers invited by journal 31 Mar, 2026 Editor assigned by journal 31 Mar, 2026 Editor invited by journal 23 Mar, 2026 Submission checks completed at journal 23 Mar, 2026 First submitted to journal 23 Mar, 2026 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9080685","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":617510598,"identity":"5160e0d5-6872-44af-8be7-f9a4822845bb","order_by":0,"name":"Yiming Ding","email":"","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yiming","middleName":"","lastName":"Ding","suffix":""},{"id":617510599,"identity":"024b731e-71c1-4da4-8bcd-c0099bbf0252","order_by":1,"name":"Xinyu Song","email":"","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xinyu","middleName":"","lastName":"Song","suffix":""},{"id":617510600,"identity":"471ea3dc-8d26-412f-8dfa-af507dd584ab","order_by":2,"name":"Xin Liang","email":"","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xin","middleName":"","lastName":"Liang","suffix":""},{"id":617510601,"identity":"22b3d386-5003-4f93-b163-18f63e0785cc","order_by":3,"name":"Defeng Liu","email":"","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Defeng","middleName":"","lastName":"Liu","suffix":""},{"id":617510602,"identity":"5d730d14-b930-417c-8036-979731b3b204","order_by":4,"name":"Longqi Liu","email":"","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Longqi","middleName":"","lastName":"Liu","suffix":""},{"id":617510603,"identity":"5c7e4a52-7174-45c7-8cfe-b7c8cc4bc346","order_by":5,"name":"Yibing Su","email":"","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yibing","middleName":"","lastName":"Su","suffix":""},{"id":617510604,"identity":"7f1a85a6-4bee-4e71-8843-c5c15502e59a","order_by":6,"name":"Liang SHI","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIie3PsQrCMBCA4SuFdCm6FgTzCnFx076KpVBXHQWHSCGjXQu+hI9QOdRXEOzQLt1dpIOISdW1zSiYf7kM98EFwGT6xTxrk83kJLa1KYDpEd6QnmPHTJMAZGoO+47wtO6iu5hnxTqfCtsSq3qRU3DwuG8jLD/Iw05VqMjVZdWIu1F0aSVeIAnBkCgCDC3uueNWQlNFnm+yrBn6nQQukgQCp4qAyzDoJKwhW5xJEg8kCUXXX2g6L8v6jj5NzuWtfuAkcfDUftingH9fRGdd5esumkwm0x/2An9TUCETutZJAAAAAElFTkSuQmCC","orcid":"","institution":"Beijing Jishuitan Hospital, Capital Medical University","correspondingAuthor":true,"prefix":"","firstName":"Liang","middleName":"","lastName":"SHI","suffix":""}],"badges":[],"createdAt":"2026-03-10 07:41:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9080685/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9080685/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106300815,"identity":"60f35377-99b1-40a9-a7ca-2ce38972723e","added_by":"auto","created_at":"2026-04-07 09:16:40","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":23119583,"visible":true,"origin":"","legend":"\u003cp\u003eCT and MRI examinations of 6 cases, including T1, T2 and contrast-enhanced T1. Cases 1-3 are Ossified Spinal Meningiomas, Cases Psammomatous Spinal Meningiomas. The tumor locations are indicated by red arrows.\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-9080685/v1/21e12dfd706e6f032a15b251.png"},{"id":106300819,"identity":"e42803b9-3684-40ae-84d3-cf3d3c0f84cd","added_by":"auto","created_at":"2026-04-07 09:16:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":149098,"visible":true,"origin":"","legend":"\u003cp\u003eThe signal ratio in CT and MRI. (A) The CT signal ratio in OSM is significantly higher than that in PSM. (B)The T1 signal ratio in OSM is lower than that in PSM. (C)The T2 signal ratio in OSM is significantly lower than that in PSM. (D)The T1 contrast-enhanced signal ratio in OSM is lower than that in PSM.\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-9080685/v1/4c1077b57bcf8e8889f7368d.png"},{"id":106300818,"identity":"0e4dc1c7-9928-4253-9c8d-b73aacb08e75","added_by":"auto","created_at":"2026-04-07 09:16:40","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":7012612,"visible":true,"origin":"","legend":"\u003cp\u003eIllustrated surgical approach. (A) Tumor located on the ventral aspect of the spinal cord. (B) Resection margin of the ipsilateral pedicle appropriately expanded. (C) Operating table angle adjusted to accommodate the surgical approach.\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-9080685/v1/3a284dcc7f94e4aaa1f14ba1.png"},{"id":108490716,"identity":"d081f7e0-808f-4a1e-8565-3a41c75c5005","added_by":"auto","created_at":"2026-05-05 09:47:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":18331158,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9080685/v1/abc3f22e-d483-4eb5-9429-66b7ac4ba5a9.pdf"},{"id":106404028,"identity":"596c1af1-bf68-41ce-92ae-855ad30c9056","added_by":"auto","created_at":"2026-04-08 09:15:23","extension":"mp4","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":17396338,"visible":true,"origin":"","legend":"","description":"","filename":"video1.mp4","url":"https://assets-eu.researchsquare.com/files/rs-9080685/v1/a311f37d58edcbff0f5278fb.mp4"},{"id":106300817,"identity":"7a70397d-f7b2-47a9-b339-525f08e67ef0","added_by":"auto","created_at":"2026-04-07 09:16:40","extension":"mp4","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":9886289,"visible":true,"origin":"","legend":"","description":"","filename":"video2.mp4","url":"https://assets-eu.researchsquare.com/files/rs-9080685/v1/fdae4a157fb0e28d45e49c0e.mp4"}],"financialInterests":"No competing interests reported.","formattedTitle":"Differential Diagnosis of Ossified Spinal Meningiomas from Psammomatous Spinal Meningiomas Based on CT and MRI and Surgical Strategy","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSpinal meningioma is among the most common primary spinal tumors\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. The ossifying spinal meningioma (OSM) is a subtype of meningioma characterized by metaplastic ossification\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, which distinguishes it from the calcification observed in psammomatous spinal meningiomas (PSMs)\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. On the basis of histological characteristics, both PSMs and OSMs are calcified\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e, but their surgical approaches differ. Ossifying meningiomas pose a challenge for neurosurgeons because partial resection is not feasible\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Therefore, it is important to distinguish between OSMs and PSMs before surgery, as this helps determine the treatment plan. For ossifying meningioma, the surgical approach should be expanded to protect nerve function and achieve complete tumor resection. The aim of this study was to distinguish OSMs from PSMs using imaging techniques to guide surgical treatment.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eData collection\u003c/p\u003e \u003cp\u003e We retrospectively reviewed all spinal meningioma patients who underwent surgery at our hospital from January 2021 to December 2024. The inclusion criteria were as follows: 1) Patients who were newly diagnosed with an ossified meningioma, PSM or calcified meningioma, those who were surgically treated for these tumors, and patients with histologic confirmation of these tumors. 2) Patients who underwent preoperative CT and MRI, including T1, T2 and contrast-enhanced T1. 3) Patients who were followed-up for 3 to 12 months after surgery 4) Patients with available basic information, which included sex, age at surgery, symptoms, signs, and the relationship between the tumor and spinal cord location. All patients provided informed consent before inclusion in the study.\u003c/p\u003e \u003cp\u003eImage acquisition\u003c/p\u003e \u003cp\u003eThe slice thickness for CT scans is 1 millimeter, and MR imaging was performed at 3T. The imaging methods include the T1 inversion recovery sequence, the T2-weighted multispin sequence, and the T1-weighted contrast-enhanced sequence. After the imaging dataset is standardized, tumor characteristics are described using the relative signal ratio. The signal ratio in CT refers to the ratio of tumor signal intensity to that of the vertebral trabecular bone, whereas in MRI, the signal ratio denotes the ratio of tumor signal intensity to that of normal spinal cord tissue. After each sequence was repeated three times, the average value was taken.\u003c/p\u003e \u003cp\u003eSurgical management\u003c/p\u003e \u003cp\u003eThe patient was placed in a prone position under general anesthesia. After preoperative localization using a C-arm machine, a laminectomy was performed at one or more segments based on the extent and location of the tumor to further expose the dura mater. Different surgical strategies were adopted according to the specific positional relationship between the tumor and the spinal cord: ① For tumors located dorsally or laterally to the spinal cord, the dura was incised along the midline, and the tumor was carefully resected en bloc. ② For tumors located ventrally to the spinal cord, the resection range of the ipsilateral pedicle was appropriately expanded, and the surgical table was tilted to facilitate tumor removal from a slightly lateral approach relative to the spinal cord. Following complete tumor resection and confirmation of no active bleeding, the dura was closed with sutures. No internal spinal fixation was performed during the procedure. Intraoperative electrophysiological monitoring (neuromonitoring) was performed throughout the surgery to ensure neurological safety.\u003c/p\u003e \u003cp\u003eIntraoperative neurophysiological neuromonitoring\u003c/p\u003e \u003cp\u003eIntraoperative electrophysiological monitoring of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) was performed. After successful anesthesia, electrodes were placed, and no muscle relaxants were used during surgery to ensure accurate monitoring. Transcutaneous electrical stimulation was applied before and after laminectomy, before and after the dura mater incision, before and after tumor resection, and after dura mater closure to monitor whether surgical manipulation caused nerve damage. Spontaneous electrical activity in muscles and other tissues generates free-running signals. When evoked potentials are monitored, the integrity of the nervous system can be assessed by applying stimuli of known intensity, duration, and frequency at one end of the neural pathway and by measuring the response in volts at the other end. The alarm criteria were a decrease in amplitude exceeding 50% of the baseline or a prolongation of the latency exceeding 10% of the baseline\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. When an alarm occurred, surgical manipulation was immediately stopped, the area was left undisturbed for several minutes to identify the cause, and to prevent nerve injury, surgery was resumed only after the patient\u0026rsquo;s electromyographic response had recovered.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eSPSS version 25.0 (IBM Corp., Armonk, New York, USA) was used for statistical analyses. The normal distribution was checked with the Shapiro\u0026ndash;Wilk test. Independent samples t tests were used to compare the CT and MRI signal ratios between the OSM and the PSM groups. Chi-square tests were used to compare sex and age between the OSM and PSM, respectively groups. P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 indicated statistical significance.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eClinical results\u003c/p\u003e \u003cp\u003eIn this study, data were collected from 48 patients who were diagnosed with gritty meningioma, calcified meningioma, or ossifying meningioma (41 women and 7 men; mean age: 61.0\u0026thinsp;\u0026plusmn;\u0026thinsp;11.8 years; age range: 24\u0026ndash;79 years). Fifteen patients experienced pain symptoms, 31 patients experienced numbness, 21 patients exhibited decreased muscle strength, 5 patients had diminished pain and temperature sensation, and 17 patients reported subjective limb weakness.\u003c/p\u003e \u003cp\u003eMRI findings\u003c/p\u003e \u003cp\u003ePatients with a pathological diagnosis of ossified meningioma and those with bone components within the tumor tissue were assigned to the OSM group(Figure-1). Patients with a pathological diagnosis of psammomatous or calcified meningioma were assigned to the PSM group. The CT signal ratio in the OSM group (mean 2.45) was significantly greater than that in the PSM group (mean 0.65) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The T1 signal ratio in the OSM group (mean 0.79) was lower than that in the PSM group (mean 1.09) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The T2 signal ratio in the OSM group (mean 0.71) was significantly lower than that in the PSM group (mean 1.54) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The T1 contrast-enhanced signal ratio in the OSM group (mean 0.1.42) was lower than that in the PSM group (mean 1.95) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) ༈Figure-2, Table-1༉.\u003c/p\u003e \u003cp\u003eOutcome\u003c/p\u003e \u003cp\u003eAll patients underwent microsurgical subdural tumor resection via the posterior median approach under electrophysiological monitoring, with complete tumor resection achieved in all patients. Pain relief was achieved in 8 patients, numbness resolution was achieved in 33 patients, and weakness was improved in 4 patients. Sensory loss (pain and temperature) resolved in 3 patients, muscle strength recovered in 10 patients with prior weakness, and muscle strength decreased in 3 patients. All patients were followed-up for 3\u0026ndash;12 months after surgery in an outpatient setting. Follow-up MRI scans revealed no tumor recurrence.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eMeningiomas account for approximately 25\u0026ndash;30% of all spinal cord tumors\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Women are at a significantly greater risk for the development of spinal meningiomas than are men\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Spinal meningiomas are most commonly found in elderly women, and their peak incidence occurs at approximately age 70 years\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Ossified meningiomas (OSMs) are extremely rare and account for approximately 1% of all meningiomas\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Ossified meningiomas are considered to evolve from calcified meningiomas. Calcification in meningiomas is secondary to the metaplasia of arachnoid cells and not to psammomatous features\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Due to the limited space within the spinal canal, symptoms typically manifest rapidly on the basis of the texture and structure of the OSM\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Due to its hard-rock texture and extensive adhesion to surrounding critical spinal cord structures, surgical treatment of OSM is highly complex and may affect patient prognosis\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAs a result of differences in signal intensity between calcification and ossification, the two can be distinguished on imaging. To date, no systematic comparison of the imaging characteristics of these two tumors has been conducted. For calcified meningiomas, CT scans may occasionally reveal distinct nodular and layered areas of high signal intensity, whereas MRI images typically lack such prominent features\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Among 11 patients with pathologically confirmed PSMs, 10 exhibited significant calcification on CT scans\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Ossifying meningioma presents as a dense lesion on CT and has low signal intensity on T2-weighted imaging (T2WI)\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Ossifying meningioma appears as a high-density lesion on CT scans and demonstrates low signal intensity on T2-weighted images\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. These reports are consistent with the findings of this study. The results of this study indicate that the CT scan density values of the OSM group are more than twice those of the PSM group. In T2-weighted MR images, the signal intensity of OSM was significantly lower than that of PSM. Therefore, preoperative radiomics analysis can distinguish between OSM and PSM, a method that can help guide surgical planning.Calcified meningiomas and ossifying meningiomas are more readily identified by CT\u003csup\u003e4\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSurgery is the preferred treatment for OSM, and because partial resection is not feasible (video 1), complete resection is the only option(video 2), and thus OSM is a persistent challenge for surgeons. Many authors believe that the posterior midline approach, through extensive resection of the lamina and pedicles extending to the posterior aspect of the vertebral body, provides adequate tumor exposure, thereby offering a lateral access pathway for tumor resection\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. In the surgical approach described by Jitendra et al., the extension of unilateral hemilaminectomy into the medial region of the pedicle not only alleviated postoperative pain and discomfort but also maintained spinal stability and promoted early rehabilitation\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Regardless of the surgical approach, the goal is to avoid manipulation of the spinal cord, as even the slightest traction or compression may lead to a worsened prognosis\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eTherefore, the management of intraoperative OSM becomes critically important. Some authors recommend the use of high-speed diamond drill bits in conjunction with ultrasonic surgical aspirators to achieve safe and effective tumor resection while avoiding spinal cord stimulation\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. However, we believe that this approach is associated with a risk of neurovascular injury; thus, we advocate the use of a wider surgical approach to remove the tumor. When the tumor is located on the ventral side of the spinal cord, we believe that it is necessary to appropriately expand the resection of the ipsilateral lamina, retract the dura mater ipsilaterally (or perform a T-shaped incision of the dura mater), and adjust the operating table angle to resect the tumor from a more lateral-to-medial approach relative to the spinal cord (Figure-3). Electrophysiological monitoring was performed throughout the entire surgical procedure to ensure the maintenance of neural function.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAn OSM is a rare type of meningioma that is distinct from a PSM. Surgical resection of ossified meningioma is challenging, and thus preoperative imaging assessment is crucial for guiding the surgical strategy. Tumors located on the ventral aspect of the spinal cord can be safely and completely resected through specialized surgical approaches and intraoperative neurophysiological neuromonitoring.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eOssified spinal meningiomas \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;OSMs\u003c/p\u003e\n\u003cp\u003ePsammomatous spinal meningiomas\u0026nbsp; \u0026nbsp;PSMs\u003c/p\u003e\n\u003cp\u003ecomputed tomography \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;CT\u003c/p\u003e\n\u003cp\u003emagnetic resonance imaging \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; MRI\u003c/p\u003e\n\u003cp\u003esomatosensory evoked potentials \u0026nbsp; \u0026nbsp;\u0026nbsp;SEPs\u003c/p\u003e\n\u003cp\u003emotor evoked potentials \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;MEPs\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors of this manuscript consent to participate.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe corresponding author, Liang Shi, provided overall supervision, secured funding, coordinated the project, and critically reviewed and finalized the manuscript. Yiming Ding contributed to the study conception and design, data acquisition, interpretation of results, and drafting of the manuscript. Xinyu Song was responsible for clinical data collection, figure preparation. Xin Liang assisted with study design and ethical oversight, Defeng Liu contributed to statistical analysis, Longqi Liu provided data validation and participated in manuscript revision, Yibing Su contributed to data interpretation and clinical expertise. All authors reviewed the manuscript, approved its final version, and agree to be accountable for all aspects of the work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was supported by This work was supported by\u0026nbsp;Beijing Municipal Administration of Hospitals Incubating Program (PX2020018), Beijing Jishuitan Hospital Elite Young Scholar Programme (XKGG202115), Beijing Jishuitan Research Funding，Beijing Jishuitan Hospital, Capital Medical University (ZR-202510), Beijing Jishuitan Research Funding，Beijing Jishuitan Hospital, Capital Medical University（QN-202503）\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval All procedures performed in studies involving human participants were conducted in accordance with the ethical standards of Beijing Jishuitan Hospital, Capital Medical University[Ethics Committee of Beijing Jishuitan Hospital: K2023-144-00], and with the1964 Helsinki Declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHuman Ethics and Consent to Participate declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll studies obtained informed consent from participants. The patients provided their written informed consent to participate in this study. Written informed consent was obtained from the individuals for the publication of any potentially identifiable images or data included in this article\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRavindra VM, Schmidt MH. Spinal Meningiomas: Diagnosis, Surgical Management, and Adjuvant Therapies. \u003cem\u003eNeurosurgery clinics of North America. \u003c/em\u003e2023;34(3):425-435.\u003c/li\u003e\n\u003cli\u003eKitagawa M, Nakamura T, Aida T. Clinicopathologic analysis of ossification in spinal meningioma. Article in Japanese. 1994;11(1):115-119.\u003c/li\u003e\n\u003cli\u003eYamane K, Tanaka M, Sugimoto Y. Spinal metaplastic meningioma with osseous differentiation in the ventral thoracic spinal canal. 2014;68(5):313-316.\u003c/li\u003e\n\u003cli\u003eRuggeri AG, Fazzolari B, Colistra D, Cappelletti M, Marotta N, Delfini R. Calcified Spinal Meningiomas. \u003cem\u003eWorld neurosurgery. \u003c/em\u003e2017;102:406-412.\u003c/li\u003e\n\u003cli\u003eAlafaci C, Grasso G, Granata F, Salpietro FM, Tomasello F. Ossified spinal meningiomas: Clinical and surgical features. \u003cem\u003eClinical neurology and neurosurgery. \u003c/em\u003e2016;142:93-97.\u003c/li\u003e\n\u003cli\u003eAdkins GB, Mirallave Pescador A, Koht AH, Gosavi SP. Intraoperative neuromonitoring in intracranial surgery. \u003cem\u003eBJA education. \u003c/em\u003e2024;24(5):173-182.\u003c/li\u003e\n\u003cli\u003eCorell A, Cerbach C, Hoefling N, Bj\u0026ouml;rkman-Burtscher IM, Jakola AS. Spinal cord compression in relation to clinical symptoms in patients with spinal meningiomas. \u003cem\u003eClinical neurology and neurosurgery. \u003c/em\u003e2021;211:107018.\u003c/li\u003e\n\u003cli\u003eDiGiorgio AM, Virk MS, Mummaneni PV. Spinal meningiomas. \u003cem\u003eHandbook of clinical neurology. \u003c/em\u003e2020;170:251-256.\u003c/li\u003e\n\u003cli\u003eDang DD, Mugge LA, Awan OK, Gong AD, Fanous AA. Spinal Meningiomas: A Comprehensive Review and Update on Advancements in Molecular Characterization, Diagnostics, Surgical Approach and Technology, and Alternative Therapies. 2024;16(7):1426.\u003c/li\u003e\n\u003cli\u003eBarresi V, Caffo M, Ieni A, Alafaci C, Tuccari G. Osteoblastic meningiomas: clinico-pathological and immunohistochemical features of an uncommon variant. \u003cem\u003eJournal of neuro-oncology. \u003c/em\u003e2011;105(2):225-232.\u003c/li\u003e\n\u003cli\u003eCaffo M, Caruso G, Barresi V, Tomasello F. Ossified Intracranial Meningiomas: Description of the First Series of Cases and Review of the Literature. \u003cem\u003eWorld neurosurgery. \u003c/em\u003e2016;94:458-464.\u003c/li\u003e\n\u003cli\u003eZhu Q, Qian M, Xiao J, Wu Z, Wang Y, Zhang J. Myelopathy due to calcified meningiomas of the thoracic spine: minimum 3-year follow-up after surgical treatment. \u003cem\u003eJournal of neurosurgery Spine. \u003c/em\u003e2013;18(5):436-442.\u003c/li\u003e\n\u003cli\u003eLee JW, Lee IS, Choi KU, et al. CT and MRI findings of calcified spinal meningiomas: correlation with pathological findings. \u003cem\u003eSkeletal radiology. \u003c/em\u003e2010;39(4):345-352.\u003c/li\u003e\n\u003cli\u003eAljalal NS, Alshoabi SA. Paraplegia as a Severe Presentation of an Unusual Form of Ossified Intradural Meningioma: Case Report. \u003cem\u003eSN Comprehensive Clinical Medicine. \u003c/em\u003e2020;2(10):1906-1909.\u003c/li\u003e\n\u003cli\u003eTaha MM, Alawamry A, Abdel-Aziz HR. Ossified Spinal Meningioma: A Case Report and a Review of the Literature. \u003cem\u003eSurgery journal (New York, NY). \u003c/em\u003e2019;5(4):e137-e141.\u003c/li\u003e\n\u003cli\u003eMurakami T, Tanishima S, Takeda C, Kato S, Nagashima H. Ossified Metaplastic Spinal Meningioma Without Psammomatous Calcification: A Case Report. \u003cem\u003eYonago acta medica. \u003c/em\u003e2019;62(2):232-235.\u003c/li\u003e\n\u003cli\u003eFreidberg S. Removal of an ossified ventral thoracic meningioma. Case report. 1972;37(6):728-730.\u003c/li\u003e\n\u003cli\u003eThakur J, Ulrich CT, Sch\u0026auml;r RT, Seidel K, Raabe A, Jesse CM. The surgical challenge of ossified ventrolateral spinal meningiomas: tricks and pearls for managing large ossified meningiomas of the thoracic spine. \u003cem\u003eJournal of neurosurgery Spine. \u003c/em\u003e2021;35(4):516-526.\u003c/li\u003e\n\u003cli\u003eChotai S, Mrak R, Mutgi S, Medhkour A. Ossification in an extra-intradural spinal meningioma-pathologic and surgical vistas. 2013;13(12):e21-e26.\u003c/li\u003e\n\u003cli\u003eCochran E, Schlauderaff A, Rand S. Spinal osteoblastic meningioma with hematopoiesis: radiologic-pathologic correlation and review of the literature. 2016;24:30-34.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003eTable1. Details of\u0026nbsp;signal ratio\u0026nbsp;in CT and MRI.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 196px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003eOSM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003ePSM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 196px;\"\u003e\n \u003cp\u003eMean of CT-signal ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e2.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e0.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e＜0.0001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 196px;\"\u003e\n \u003cp\u003eMean of T1-signal ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e0.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e1.09\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.0042\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 196px;\"\u003e\n \u003cp\u003eMean of T2-signal ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e0.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e1.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.0378\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 196px;\"\u003e\n \u003cp\u003eMean of Tce-signal ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e1.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e1.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.0425\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Ossified spinal meningiomas, Psammomatous spinal meningiomas, Surgical treatment, Radiomics, Intraoperative neurophysiological neuromonitoring","lastPublishedDoi":"10.21203/rs.3.rs-9080685/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9080685/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e \u003cp\u003eOssified spinal meningiomas (OSMs) and psammomatous spinal meningiomas (PSMs) each exhibit distinct histological features. Surgical approaches also differ between the two types. Preoperative differentiation between OSMs and PSMs aids in treatment planning. This study aims to distinguish OSMs from PSMs through imaging.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eDifferences between OSMs and PSMs were compared using computed tomography (CT) and magnetic resonance imaging (MRI). The key points of surgery for OSMs were also summarized.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eOn the basis of the pathological findings, the patients were divided into OSM and PSM groups. Imaging analysis revealed that the CT signal ratio (2.45) was significantly greater in the OSM group than in the PSM group (0.65), while the T1, T2, and T1 contrast-enhanced signal ratios (0.79, 0.71, and 1.42, respectively) were significantly lower in the OSM group than in the PSM group (1.09, 1.54, and 1.95, respectively; all p values\u0026thinsp;\u0026lt;\u0026thinsp;0.001). All patients underwent complete tumor resection. Most patients experienced symptomatic improvement after surgery, and no tumor recurrence was observed during follow-up.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe imaging features differ between OSMs and PSMs. Through specialized surgical approaches and intraoperative neurophysiological monitoring, tumors located on the ventral aspect of the spinal cord can be safely and completely resected.\u003c/p\u003e","manuscriptTitle":"Differential Diagnosis of Ossified Spinal Meningiomas from Psammomatous Spinal Meningiomas Based on CT and MRI and Surgical Strategy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-07 09:16:29","doi":"10.21203/rs.3.rs-9080685/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-04T11:17:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"329554816701906542255274839718914085187","date":"2026-04-04T11:03:24+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-01T00:40:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-01T00:39:30+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-23T15:16:18+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-23T09:20:17+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Neurology","date":"2026-03-23T08:43:27+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8ff69752-6242-4a01-9de7-34acad41c77b","owner":[],"postedDate":"April 7th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-07T09:16:29+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-07 09:16:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9080685","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9080685","identity":"rs-9080685","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}