{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T16:42:54Z","timestamp":1787071374864,"version":"build-2736575974"},"reference-count":11,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","license":[{"start":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T00:00:00Z","timestamp":1763683200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:p>\n                    Atypical parkinsonian disorders (APD), such as progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal syndrome (CBS), and Lewy body dementia (LBD) are frequently misdiagnosed, commonly as Parkinson\u2019s disease (PD). The study aims to assess the utility of the interpeduncular angle (IPA) in distinguishing APD from PD across age ranges. This retrospective study was conducted with 225 patients (75 with APD, 75 with PD, and 75 healthy controls). Patients were categorized into three age groups: (51\u201360, 61\u201370, and 71\u201380 years). Two independent raters measured the IPA from T1-weighted axial brain magnetic resonance images (MRIs) at a level below the mammillary bodies using standardized measurement techniques. The APD group included 51 (68%) with PSP, 16 (21.33%) with MSA, 5 (6.67%) with LBD, and 3 (4%) with CBS. Bland-Altman analysis for angle measurement suggested good to excellent agreement between raters (\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt; 0.001). IPA measurements among the different diagnostic groups showed that PSP was higher than controls (\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt; 0.001) and PD (\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt; 0.001), and MSA was higher than controls (\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt; 0.001) and PD (\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    = 0.003). There was no significant association between IPA and age in the APD phenotypes. With increasing age, the significance between APD and IPD groups decreased (\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    &lt; 0.001 in 51\u201360 years to\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    = 0.686 in 71\u201380 years). Receiver Operating Characteristic (ROC) analysis revealed increasing IPA thresholds for PSP versus PD (67.66\u00b0 in 51\u201360 years to 75.71\u00b0 in 71\u201380 years). IPA is not reliable in differentiating APD, particularly PSP and MSA, from PD and controls.\n                  <\/jats:p>","DOI":"10.4103\/aian.aian_357_25","type":"journal-article","created":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T12:00:15Z","timestamp":1763726415000},"page":"71-75","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Interpeduncular Angle: A Possible Marker to Differentiate Atypical Parkinsonism from Idiopathic Parkinson\u2019s Disease"],"prefix":"10.4103","volume":"29","author":[{"given":"Tejas","family":"Shivarthi","sequence":"first","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mahima","family":"Sriram","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Udit","family":"Saraf","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rajesh","family":"Kannan","sequence":"additional","affiliation":[{"name":"Department of Radiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sudheeran","family":"Kannoth","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abish","family":"Sudhakar","sequence":"additional","affiliation":[{"name":"Department of Pediatric Cardiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vivek","family":"Nambiar","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siby","family":"Gopinath","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gopikrishnan","family":"Unnikrishnan","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anandkumar","family":"Anandakuttan","sequence":"additional","affiliation":[{"name":"Department of Neurology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidhyapeetham, Kochi, Kerala, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2025,11,21]]},"reference":[{"key":"R1-20260420","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1212\/CON.0000000000000348","article-title":"Diagnostic approach to atypical Parkinsonian syndromes","volume":"22","author":"McFarland","year":"2016","journal-title":"Continuum (Minneap Minn)"},{"key":"R3-20260420","doi-asserted-by":"crossref","first-page":"386","DOI":"10.2214\/AJR.14.12724","article-title":"Cerebral peduncle angle: An objective criterion for assessing progressive supranuclear palsy richardson syndrome","volume":"205","author":"Fatterpekar","year":"2015","journal-title":"Am J Roentgenol"},{"key":"R4-20260420","doi-asserted-by":"crossref","first-page":"1657","DOI":"10.1007\/s00234-020-02500-1","article-title":"Magnetic resonance Parkinsonism indices and interpeduncular angle in idiopathic normal pressure hydrocephalus and progressive supranuclear palsy","volume":"62","author":"Ugga","year":"2020","journal-title":"Neuroradiology"},{"key":"R5-20260420","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1080\/01616412.2018.1541115","article-title":"MRI evaluation of progressive supranuclear palsy: Differentiation from Parkinson\u2019s disease and multiple system atrophy","volume":"41","author":"Eraslan","year":"2019","journal-title":"Neurol Res"},{"key":"R6-20260420","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.parkreldis.2016.08.009","article-title":"Cerebral peduncle angle: Unreliable in differentiating progressive supranuclear palsy from other neurodegenerative diseases","volume":"32","author":"Tipton","year":"2016","journal-title":"Parkinsonism Relat Disord"},{"key":"R7-20260420","doi-asserted-by":"crossref","first-page":"1299","DOI":"10.3174\/ajnr.A6120","article-title":"The interpeduncular angle: A practical and objective marker for the detection and diagnosis of intracranial hypotension on brain MRI","volume":"40","author":"Wang","year":"2019","journal-title":"Am J Neuroradiol"},{"key":"R8-20260420","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.parkreldis.2017.10.020","article-title":"MR planimetry in neurodegenerative parkinsonism yields high diagnostic accuracy for PSP","volume":"46","author":"Mangesius","year":"2018","journal-title":"Parkinsonism and Related Disorders"},{"key":"R9-20260420","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/j.parkreldis.2020.11.019","article-title":"Diagnostic accuracy of MR planimetry in clinically unclassifiable parkinsonism","volume":"82","author":"Heim","year":"2021","journal-title":"Parkinsonism Relat Disord"},{"key":"R10-20260420","doi-asserted-by":"crossref","first-page":"1766","DOI":"10.1212\/01.WNL.0000068011.21396.F4","article-title":"Atrophy of superior cerebellar peduncle in progressive supranuclear palsy","volume":"60","author":"Tsuboi","year":"2006","journal-title":"Neurology"},{"key":"R11-20260420","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1177\/0846537119888411","article-title":"Contribution of the mesencephalon indices to differential diagnosis of Parkinsonian disorders","volume":"71","author":"Oktay","year":"2020","journal-title":"Can Assoc Radiol J"},{"key":"R12-20260420","first-page":"e10741","article-title":"Multiple system atrophy \u2013 cerebellar type: Clinical picture and treatment of an often-overlooked disorder","volume":"12","author":"Ortiz","year":"2020","journal-title":"Cureus"}],"container-title":["Annals of Indian Academy of Neurology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.4103\/aian.aian_357_25","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T15:45:08Z","timestamp":1787067908000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.4103\/aian.aian_357_25"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,21]]},"references-count":11,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.4103\/aian.aian_357_25","relation":{},"ISSN":["0972-2327","1998-3549"],"issn-type":[{"value":"0972-2327","type":"print"},{"value":"1998-3549","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,21]]},"assertion":[{"value":"2025-04-16","name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-08-27","name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}}]}}