{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,18]],"date-time":"2026-07-18T15:03:01Z","timestamp":1784386981641,"version":"3.55.0"},"reference-count":20,"publisher":"SAGE Publications","issue":"7","license":[{"start":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:00:00Z","timestamp":1782864000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:00:00Z","timestamp":1782864000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"name":"Headache Study Group of the Spanish Society of Neurology.","award":["13th Research Grant of the Headache Study Group 20"],"award-info":[{"award-number":["13th Research Grant of the Headache Study Group 20"]}]}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Cephalalgia"],"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:sec>\n                    <jats:title>Aim<\/jats:title>\n                    <jats:p>Although periaqueductal grey matter (PAG), assessed by transcranial sonography, has been proposed as a biomarker of migraine chronification, its longitudinal evolution remains unknown. This study aimed to evaluate whether changes in clinical diagnosis\u2014from chronic migraine to episodic migraine (CM\u2013EM) or from episodic migraine to chronic migraine (EM\u2013CM)\u2014were associated with modifications in PAG echogenicity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In a prospective longitudinal cohort study we reanalysed a cohort of 115 participants (65 patients with migraine and 50 controls) previously assessed in a baseline study. The follow-up was performed three years after the initial evaluation, collecting demographic, clinical (migraine-related), and sonographic variables.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Ninety-four of the 115 participants were re-evaluated at the longitudinal follow-up. Patients who converted from episodic to chronic migraine (EM\u2013CM,\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      \u2009=\u20093) showed a significantly larger PAG area (0.22 [0.16\u20130.23] cm\n                      <jats:sup>2<\/jats:sup>\n                      vs. 0.13 [0.12\u20130.16] cm\n                      <jats:sup>2<\/jats:sup>\n                      ;\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.043), a greater reduction in PAG echogenicity (\u22120.52 [\u22120.52 to \u22120.24] vs. \u22120.03 [\u22120.21 to 0.17];\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.008), and higher heterogeneity (33.88 [31.85\u201336.72] vs. 26.67 [23.33\u201338.9];\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.0344) at baseline compared with patients who remained episodic at the follow-up assessment (n\u2009=\u200918). Among patients with chronic migraine at baseline, no significant differences in PAG area, heterogeneity, or echogenicity intensity were observed between those who remained chronic and those who were classified as episodic migraine at follow-up.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Patients with chronic migraine who clinically improved (CM\u2013EM) did not show relevant between-assessment differences in the previously described PAG alterations, suggesting the persistence of these alterations despite clinical improvement. In contrast, the small group of patients who underwent EM\u2013CM transformation exhibited increased PAG heterogeneity and area at the follow-up assessment. Further studies with a larger sample size should be performed to confirm these results.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/03331024261467732","type":"journal-article","created":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T13:52:02Z","timestamp":1784209922000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Periaqueductal gray matter echogenicity: An irreversible marker of chronic migraine?"],"prefix":"10.1177","volume":"46","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3302-9347","authenticated-orcid":false,"given":"Bel\u00e9n","family":"Flores-Pina","sequence":"first","affiliation":[{"name":"University Hospital Germans Trias i Pujol"},{"name":"Department of Medicine, Universitat Aut\u00f2noma de Barcelona, Badalona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3084-053X","authenticated-orcid":false,"given":"Dolores","family":"Vilas Rol\u00e1n","sequence":"additional","affiliation":[{"name":"University Hospital Germans Trias i Pujol"},{"name":"Department of Medicine, Universitat Aut\u00f2noma de Barcelona, Badalona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0716-8784","authenticated-orcid":false,"given":"Jos\u00e9","family":"R\u00edos Guillermo","sequence":"additional","affiliation":[{"name":"Universitat Aut\u00f2noma de Barcelona"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1867-2089","authenticated-orcid":false,"given":"Mireia","family":"Gea Rispal","sequence":"additional","affiliation":[{"name":"Department of Medicine, Universitat Aut\u00f2noma de Barcelona, Badalona, Spain"},{"name":"Neurology Department, Hospital Nostra Senyora de Meritxell"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7652-8029","authenticated-orcid":false,"given":"Sara","family":"Rubio-Guerra","sequence":"additional","affiliation":[{"name":"Hospital de la Santa Creu i Sant Pau"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8279-7954","authenticated-orcid":false,"given":"Mar\u00eda","family":"Hern\u00e1ndez P\u00e9rez","sequence":"additional","affiliation":[{"name":"University Hospital Germans Trias i Pujol"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8256-7550","authenticated-orcid":false,"given":"Laura","family":"Dorado Bouix","sequence":"additional","affiliation":[{"name":"University Hospital Germans Trias i Pujol"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,7,16]]},"reference":[{"key":"e_1_3_3_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(18)30322-3"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.1038\/nrneurol.2016.93"},{"key":"e_1_3_3_4_2","doi-asserted-by":"publisher","DOI":"10.1212\/01.wnl.0000252808.97649.21"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.1177\/0333102414552532"},{"key":"e_1_3_3_6_2","doi-asserted-by":"publisher","DOI":"10.1177\/0333102417738202"},{"key":"e_1_3_3_7_2","doi-asserted-by":"publisher","DOI":"10.1177\/0333102420974359"},{"key":"e_1_3_3_8_2","doi-asserted-by":"publisher","DOI":"10.1177\/03331024251387721"},{"key":"e_1_3_3_9_2","doi-asserted-by":"publisher","DOI":"10.3390\/ijms24065334"},{"key":"e_1_3_3_10_2","doi-asserted-by":"publisher","DOI":"10.1111\/head.12174"},{"key":"e_1_3_3_11_2","doi-asserted-by":"publisher","DOI":"10.1186\/s10194-025-02023-1"},{"key":"e_1_3_3_12_2","doi-asserted-by":"publisher","DOI":"10.3389\/fpain.2021.812209"},{"key":"e_1_3_3_13_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1468-2982.2008.01723.x"},{"key":"e_1_3_3_14_2","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0000000000007047"},{"key":"e_1_3_3_15_2","doi-asserted-by":"publisher","DOI":"10.1046\/j.1526-4610.2001.041007629.x"},{"key":"e_1_3_3_16_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1526-4610.2011.02056.x"},{"key":"e_1_3_3_17_2","doi-asserted-by":"publisher","DOI":"10.1186\/s10194-023-01576-3"},{"key":"e_1_3_3_18_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(08)70239-4"},{"key":"e_1_3_3_19_2","doi-asserted-by":"publisher","DOI":"10.1001\/archneur.59.6.999"},{"key":"e_1_3_3_20_2","doi-asserted-by":"publisher","DOI":"10.1111\/head.12774"},{"key":"e_1_3_3_21_2","doi-asserted-by":"publisher","DOI":"10.1186\/s10194-019-1038-4"}],"container-title":["Cephalalgia"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/03331024261467732","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/03331024261467732","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/03331024261467732","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,18]],"date-time":"2026-07-18T14:17:04Z","timestamp":1784384224000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/03331024261467732"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7]]},"references-count":20,"journal-issue":{"issue":"7","published-print":{"date-parts":[[2026,7]]}},"alternative-id":["10.1177\/03331024261467732"],"URL":"https:\/\/doi.org\/10.1177\/03331024261467732","relation":{},"ISSN":["0333-1024","1468-2982"],"issn-type":[{"value":"0333-1024","type":"print"},{"value":"1468-2982","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7]]},"article-number":"03331024261467732"}}