Weiling Lee1, Amanda Lee1, Huihua Li2,3, Nicholas Yu Xuan Ong1, Nicole Keong2,4, Robert Chen1,2, Ling Ling Chan5,6. 1. Department of Diagnostic Radiology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore. 2. Duke-NUS Medical School, Singapore, Singapore. 3. Health Services Research Unit, Singapore General Hospital, Singapore, Singapore. 4. Department of Neurosurgery, National Neuroscience Institute, Singapore, Singapore. 5. Department of Diagnostic Radiology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore. chan.ling.ling@sgh.com.sg. 6. Duke-NUS Medical School, Singapore, Singapore. chan.ling.ling@sgh.com.sg.
Abstract
PURPOSE: The callosal angle (CA) is a useful biomarker in the diagnosis and management of idiopathic normal pressure hydrocephalus (NPH). Used incorrectly, CA measurements are variable, affecting its reliability as a clinical tool. Our objectives are to evaluate (i) reproducibility of established CA measurements between trained raters and (ii) impact of minor angular mal-rotations of the true coronal plane on CA measurements. METHODS: CAs were measured by two independent raters on three-dimensional isovolumetric T1-weighted brain MRI of NPH patients and healthy controls using the established true coronal plane reformatted orthogonal to the plane containing the anterior-posterior commissural (AC-PC) line at the level of the posterior commissure. CA changes were subsequently evaluated when the coronal plane was mal-rotated by ± 5° and ± 10° in anterior-posterior and clockwise-anticlockwise directions. Inter-rater reliability of CA measurements was assessed using the intraclass correlation coefficient (ICC). RESULTS: On the true coronal plane, inter-rater ICC was excellent (0.973) for NPH patients and good (0.875) for controls. On mal-rotated coronal plane setups, ICC for CA was worse in controls (0.484-0.886) than NPH (0.879-0.981) groups and in clockwise-anticlockwise (0.484-0.956) than anterior-posterior (0.503-0.981) mal-rotations. CA changes secondary to mal-rotations from the true coronal plane were significant in NPH patients (P < 0.0001 to 0.0378) but not in controls (P > 0.1). CONCLUSION: This is the first demonstration of how small angular mal-rotations of the coronal plane used for CA measurement affect its value and inter-rater reliability, highlighting the importance of a standardized protocol when measuring the CA in NPH workup.
PURPOSE: The callosal angle (CA) is a useful biomarker in the diagnosis and management of idiopathic normal pressure hydrocephalus (NPH). Used incorrectly, CA measurements are variable, affecting its reliability as a clinical tool. Our objectives are to evaluate (i) reproducibility of established CA measurements between trained raters and (ii) impact of minor angular mal-rotations of the true coronal plane on CA measurements. METHODS: CAs were measured by two independent raters on three-dimensional isovolumetric T1-weighted brain MRI of NPH patients and healthy controls using the established true coronal plane reformatted orthogonal to the plane containing the anterior-posterior commissural (AC-PC) line at the level of the posterior commissure. CA changes were subsequently evaluated when the coronal plane was mal-rotated by ± 5° and ± 10° in anterior-posterior and clockwise-anticlockwise directions. Inter-rater reliability of CA measurements was assessed using the intraclass correlation coefficient (ICC). RESULTS: On the true coronal plane, inter-rater ICC was excellent (0.973) for NPH patients and good (0.875) for controls. On mal-rotated coronal plane setups, ICC for CA was worse in controls (0.484-0.886) than NPH (0.879-0.981) groups and in clockwise-anticlockwise (0.484-0.956) than anterior-posterior (0.503-0.981) mal-rotations. CA changes secondary to mal-rotations from the true coronal plane were significant in NPH patients (P < 0.0001 to 0.0378) but not in controls (P > 0.1). CONCLUSION: This is the first demonstration of how small angular mal-rotations of the coronal plane used for CA measurement affect its value and inter-rater reliability, highlighting the importance of a standardized protocol when measuring the CA in NPH workup.
Authors: K Kockum; O Lilja-Lund; E-M Larsson; M Rosell; L Söderström; J Virhammar; K Laurell Journal: Eur J Neurol Date: 2018-02-02 Impact factor: 6.089
Authors: Nityanand Miskin; Hersh Patel; Ana M Franceschi; Benjamin Ades-Aron; Alexander Le; Brianna E Damadian; Christian Stanton; Yafell Serulle; James Golomb; Oded Gonen; Henry Rusinek; Ajax E George Journal: Radiology Date: 2017-05-10 Impact factor: 11.105
Authors: Nicole C H Keong; Alonso Pena; Stephen J Price; Marek Czosnyka; Zofia Czosnyka; John D Pickard Journal: Neurosurg Focus Date: 2016-09 Impact factor: 4.047
Authors: Ling Ling Chan; Robert Chen; Huihua Li; Amanda J Y Lee; Wei Ying Go; Weiling Lee; Christine Lock; Sumeet Kumar; Adeline S L Ng; Nagaendran Kandiah; Louis C S Tan; Eng King Tan; Nicole C H Keong Journal: Eur Radiol Date: 2021-05-15 Impact factor: 5.315