Question 2829
{"accessible":false,"alternatives":[{"id":13806,"text":"a higher pulse repetition frequency"},{"id":13807,"text":"a longer pulse duration"},{"id":13808,"text":"a longer receive time"},{"id":13809,"text":"a lower Q factor pulse"}],"archived":false,"correctAlternativeId":13807,"explanation":"\u003cp\u003eColor Doppler requires a high Q factor pulse because Doppler imaging requires the detection of frequency changes to determine Doppler shift. Therefore, the range of frequencies produced by the Doppler probe needs to be narrower than B-mode imaging. \u003c/p\u003e\u003cp\u003eThe reduced damping (which increases Q factor) causes a longer pulse duration. In B-mode and color Doppler the receive time will be identical for imaging structures at the same depth.\u003c/p\u003e\u003cp\u003eTherefore, the longer pulse duration in color Doppler results in a longer pulse repetition period. This increased pulse repetition period (and subsequent decrease in pulse repetition frequency) is responsible for the reduction in temporal resolution\u003c/p\u003e","id":2829,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2830","nextQuestionPath":"/articles/doppler-shift/questions/2828","relatedArticles":[{"id":64450,"title":"Pulse repetition frequency","link":"/articles/pulse-repetition-frequency?lang=us"},{"id":67339,"title":"Color flow Doppler (ultrasound)","link":"/articles/color-flow-doppler-ultrasound?lang=us"}],"alsoUsedIn":[{"id":1620,"kind":"RestrictedPage","title":"Page 1620 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/1620"},{"id":1984,"kind":"Course","title":"Imaging Physics: Ultrasound Peer Review - page 1984","link":"https://radiopaedia.org/courses/imaging-physics-ultrasound-peer-review/pages/1984"},{"id":1984,"kind":"Course","title":"Imaging Physics: Ultrasound - page 1984","link":"https://radiopaedia.org/courses/imaging-physics-ultrasound/pages/1984"}],"stem":"\u003cp\u003eColor Doppler has worse temporal resolution than B-mode imaging due to what?\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/2829"}],"attemptsPercentages":[{"alternativeId":"13807","percentage":46},{"alternativeId":"13809","percentage":8},{"alternativeId":"13808","percentage":20},{"alternativeId":"13806","percentage":26}],"promptToLogin":false,"questionManager":false,"articleId":"doppler-shift"}