Question 983
{"accessible":false,"alternatives":[{"id":4926,"text":"W: 80 L: 40 "},{"id":4927,"text":"W: 350 L: 50"},{"id":4928,"text":"W: 400 L: 50"},{"id":4929,"text":"W: 1500 L: -600"},{"id":4930,"text":"W: 1800 L: 400"}],"archived":false,"correctAlternativeId":4926,"explanation":"\u003cp\u003eRoutine non-contrast brain studies are usually centered on the grey matter (40 HU) and have a width of 80 HU (i.e. 40 HU on either side of the center level, from 0 to 80 HU). This encompasses most relevant pathology from CSF (0 HU) to acute blood (\u0026gt;60 HU). Note that hyperdense acute blood may exceed 80\u0026nbsp;HU and will\u0026nbsp;therefore\u0026nbsp;be indistinguishable from bone.\u0026nbsp;\u003c/p\u003e","id":983,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2307","nextQuestionPath":null,"relatedArticles":[],"alsoUsedIn":[{"id":99,"kind":"Course","title":"Emergency Radiology Course - Melbourne - page 99","link":"https://radiopaedia.org/courses/emergency-radiology-course-melbourne-2020/pages/99"},{"id":99,"kind":"Course","title":"Trauma Radiology Course - Sydney - page 99","link":"https://radiopaedia.org/courses/trauma-radiology-course-sydney-2020/pages/99"},{"id":99,"kind":"Course","title":"Trauma CT Brain Learning Pathway - page 99","link":"https://radiopaedia.org/courses/trauma-ct-brain-learning-pathway/pages/99"}],"stem":"\u003cp\u003eWhich of the following CT window width (W) and level (L) settings would be appropriate for routine non-contrast CT of the brain to easily distinguish\u0026nbsp;grey and white matter?\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/983"}],"attemptsPercentages":[{"alternativeId":"4926","percentage":85},{"alternativeId":"4928","percentage":5},{"alternativeId":"4930","percentage":1},{"alternativeId":"4929","percentage":2},{"alternativeId":"4927","percentage":7}],"promptToLogin":false,"questionManager":false,"articleId":"windowing-ct"}