{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T00:48:27Z","timestamp":1791938907903,"version":"4.3.4"},"reference-count":15,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"15","license":[{"start":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T00:00:00Z","timestamp":1791763200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Neurosurg Case Lessons"],"published-print":{"date-parts":[[2026,10,12]]},"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND<\/jats:title>\n                    <jats:p>After craniotomy, fluid may accumulate in the surgical bed, raising suspicion for hemorrhage, abscess, or postoperative pseudomeningocele. Typically, peripheral contrast enhancement, internal restricted diffusion, and adjacent edema are consistent with infection.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>OBSERVATIONS<\/jats:title>\n                    <jats:p>The authors present 4 cases with postoperative epidural fluid collections mimicking epidural abscesses on MRI with restricted diffusion on diffusion-weighted imaging. Three of these cases were associated with adjacent brain edema. The fluid appeared 1\u20133 months after the surgery on routine follow-up MRI in the absence of clinical symptoms, and nearly resolved, either spontaneously without treatment or with conservative therapy alone. Given imaging findings concerning for infection in the absence of symptoms, diagnosis and management were challenging.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>LESSONS<\/jats:title>\n                    <jats:p>When there is increased epidural fluid collection after craniotomy, radiographic findings may mimic abscess, but they are not always clinically significant. Clinical assessment is a crucial component of the diagnosis to avoid unnecessary intervention, and follow-up imaging is recommended. The pathogenesis of this restricting, enhancing fluid collection remains unclear.<\/jats:p>\n                    <jats:p>\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"https:\/\/thejns.org\/doi\/10.3171\/CASE26757\">https:\/\/thejns.org\/doi\/10.3171\/CASE26757<\/jats:ext-link>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3171\/case26757","type":"journal-article","created":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T00:01:21Z","timestamp":1791331281000},"source":"Crossref","is-referenced-by-count":0,"title":["Postoperative epidural fluid collection mimicking epidural abscess: illustrative cases"],"prefix":"10.3171","volume":"12","author":[{"given":"Alexandra J.","family":"White","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8972-4192","authenticated-orcid":true,"given":"Tetsuya","family":"Shimizu","sequence":"additional","affiliation":[{"name":"Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California"},{"name":"Department of Radiology, The Jikei University School of Medicine, Tokyo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1453-3807","authenticated-orcid":true,"given":"Sonoko","family":"Oshima","sequence":"additional","affiliation":[{"name":"Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kunal S.","family":"Patel","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard G.","family":"Everson","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4053-0052","authenticated-orcid":true,"given":"Linda M.","family":"Liau","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Noriko","family":"Salamon","sequence":"additional","affiliation":[{"name":"Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"1","key":"bib1","series-title":"Emerg Radiol","first-page":"99","article-title":"Post-operative complications of craniotomy and craniectomy","volume":"26","author":"Chughtai","year":"2019","unstructured":"Chughtai KANemer OPKessler ATBhatt AA.Post-operative complications of craniotomy and craniectomy. Emerg Radiol. 2019;26(1):99-107. doi:10.1007\/s10140-018-1647-2"},{"issue":"3","key":"bib2","series-title":"Radiology","first-page":"839","article-title":"Postoperative changes in the brain: MR imaging findings in patients without neoplasms","volume":"204","author":"Sato","year":"1997","unstructured":"Sato NBronen RASze GPostoperative changes in the brain: MR imaging findings in patients without neoplasms. Radiology. 1997;204(3):839-846. doi: 10.1148\/radiology.204.3.9280269"},{"key":"bib3","series-title":"World Neurosurg","first-page":"e245","article-title":"Value of diffusion-weighted imaging in the diagnosis of postoperative intracranial infections","volume":"118","author":"Berndt","year":"2018","unstructured":"Berndt MLange NRyang YMValue of diffusion-weighted imaging in the diagnosis of postoperative intracranial infections. World Neurosurg. 2018;118:e245-e253. doi:10.1016\/j.wneu.2018.06.167"},{"issue":"3","key":"bib4","series-title":"Neurosurgery","first-page":"577","article-title":"Limitations of diffusion-weighted imaging in the diagnosis of postoperative infections","volume":"62","author":"Farrell","year":"2008","unstructured":"Farrell CJHoh BLPisculli MLHenson JWBarker FGIICurry WTJr.Limitations of diffusion-weighted imaging in the diagnosis of postoperative infections. Neurosurgery. 2008;62(3):577-583. doi:10.1227\/01.NEU.0000311349.25281.BD"},{"issue":"1","key":"bib5","series-title":"Radiology","first-page":"168","article-title":"Postoperative versus spontaneous intracranial abscess: diagnostic value of the apparent diffusion coefficient for accurate assessment","volume":"281","author":"Lotan","year":"2016","unstructured":"Lotan EHoffmann CFardman AZiv-Baran TKomisar OHarnof S.Postoperative versus spontaneous intracranial abscess: diagnostic value of the apparent diffusion coefficient for accurate assessment. Radiology. 2016;281(1):168-174. doi:10.1148\/radiol.2016151708"},{"issue":"3","key":"bib6","series-title":"Clin Radiol","first-page":"375","article-title":"Role of diffusion-weighted MR in differential diagnosis of intracranial cystic lesions","volume":"60","author":"B\u00fckte","year":"2005","unstructured":"B\u00fckte YPaksoy YGen\u00e7 EUca AU.Role of diffusion-weighted MR in differential diagnosis of intracranial cystic lesions. Clin Radiol. 2005;60(3):375-383. doi:10.1016\/j.crad.2004.05.019"},{"issue":"6","key":"bib7","series-title":"Br J Neurosurg","first-page":"765","article-title":"The difference in diffusion-weighted imaging with apparent diffusion coefficient between spontaneous and postoperative intracranial infection","volume":"28","author":"Kim","year":"2014","unstructured":"Kim YJMoon KSKim SKThe difference in diffusion-weighted imaging with apparent diffusion coefficient between spontaneous and postoperative intracranial infection. Br J Neurosurg. 2014;28(6):765-770. doi:10.3109\/02688697.2014.931349"},{"issue":"6","key":"bib8","series-title":"Neurosurgery","first-page":"974","article-title":"Intracranial suppuration: a modern decade of postoperative subdural empyema and epidural abscess","volume":"34","author":"Hlavin","year":"1994","unstructured":"Hlavin MLKaminski HJFenstermaker RAWhite RJ.Intracranial suppuration: a modern decade of postoperative subdural empyema and epidural abscess. Neurosurgery. 1994;34(6):974- 980. doi:10.1227\/00006123-199406000-00004"},{"issue":"9","key":"bib9","series-title":"Diagnostics (Basel)","article-title":"A Rare case of aphasia caused by delayed epidural abscess 6 years after cranioplasty","volume":"12","author":"Kim","year":"2022","unstructured":"Kim JHKim DKKim SW.A Rare case of aphasia caused by delayed epidural abscess 6 years after cranioplasty. Diagnostics (Basel). 2022;12(9):2040. doi:10.3390\/diagnostics12092040"},{"issue":"1","key":"bib10","series-title":"Br J Neurosurg","first-page":"5","article-title":"Post-craniotomy intracranial infection in patients with brain tumors: a retrospective analysis of 5723 consecutive patients","volume":"31","author":"Shi","year":"2017","unstructured":"Shi ZHXu MWang YZPost-craniotomy intracranial infection in patients with brain tumors: a retrospective analysis of 5723 consecutive patients. 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J Korean Neurosurg Soc. 2006;39(5):335-339."},{"issue":"3","key":"bib13","series-title":"Eur J Cardiothorac Surg","first-page":"489","article-title":"A foreign body reaction to Surgicel mimicking an abscess following cardiac surgery","volume":"22","author":"Ibrahim","year":"2002","unstructured":"Ibrahim MFAps CYoung CP.A foreign body reaction to Surgicel mimicking an abscess following cardiac surgery. Eur J Cardiothorac Surg. 2002;22(3):489-490. doi:10.1016\/s1010-7940(02)00328-7"},{"issue":"2","key":"bib14","series-title":"Int J Clin Exp Med","first-page":"3996","article-title":"Intracranial foreign body granuloma caused by gelatin sponge: a case report and literature review","volume":"10","author":"Lei","year":"2017","unstructured":"Lei TLiu XCao JSun YLi GHuang H.Intracranial foreign body granuloma caused by gelatin sponge: a case report and literature review. Int J Clin Exp Med. 2017;10(2):3996-4000."},{"issue":"7","key":"bib15","series-title":"Int J Surg Case Rep","first-page":"338","article-title":"Oxidized cellulose (Surgicel) based reaction post thyroidectomy mimicking an abscess: a case report","volume":"3","author":"Royds","year":"2012","unstructured":"Royds JKieran STimon C.Oxidized cellulose (Surgicel) based reaction post thyroidectomy mimicking an abscess: a case report. Int J Surg Case Rep. 2012;3(7):338-339. doi:10.1016\/j.ijscr.2012.03.034"}],"container-title":["Journal of Neurosurgery: Case Lessons"],"original-title":[],"link":[{"URL":"https:\/\/thejns.org\/view\/journals\/j-neurosurg-case-lessons\/12\/15\/article-CASE26757.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/j-neurosurg-case-lessons\/12\/15\/article-CASE26757.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/j-neurosurg-case-lessons\/12\/15\/article-CASE26757.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T00:00:44Z","timestamp":1791936044000},"score":1,"resource":{"primary":{"URL":"https:\/\/thejns.org\/view\/journals\/j-neurosurg-case-lessons\/12\/15\/article-CASE26757.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,12]]},"references-count":15,"journal-issue":{"issue":"15"},"URL":"https:\/\/doi.org\/10.3171\/case26757","relation":{},"ISSN":["2694-1902"],"issn-type":[{"value":"2694-1902","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,12]]}}}