Question 2830
{"accessible":false,"alternatives":[{"id":13810,"text":"decreased Doppler angle"},{"id":13811,"text":"decreased pulse repetition frequency"},{"id":13812,"text":"decreased pulse repetition period"},{"id":13813,"text":"increased transducer frequency"},{"id":13814,"text":"placement of the sampling gate at a greater depth"}],"archived":false,"correctAlternativeId":13812,"explanation":"\u003cp\u003eThe maximum detectable velocity can be defined as follows:\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eV\u003csub\u003e(max)\u003c/sub\u003e = PRF x speed / 4 x frequency\u003csub\u003e(transducer)\u003c/sub\u003e x cos(Doppler angle)\u003c/strong\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003ePulse repetition frequency (PRF) = 1 / Pulse repetition period (PRP)\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eTherefore, a decrease in pulse repetition period will results in an increase in pulse repetition frequency. This increases the maximum detectable velocity. \u003c/p\u003e\u003cp\u003ePlacing the sampling gate at a greater depth increases the required pulse repetition period, which will decrease detectable velocity.\u003c/p\u003e\u003cp\u003eRemember, a decrease in Doppler angle results in an increase in the value of cos(Doppler angle). This will also result in a decrease in the maximum detectable velocity.\u003c/p\u003e","id":2830,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2830","nextQuestionPath":"/articles/doppler-shift/questions/2829","relatedArticles":[{"id":59274,"title":"Doppler angle correction","link":"/articles/doppler-angle-correction?lang=us"},{"id":64450,"title":"Pulse repetition frequency","link":"/articles/pulse-repetition-frequency?lang=us"},{"id":64547,"title":"Aliasing phenomenon (ultrasound)","link":"/articles/aliasing-phenomenon-ultrasound?lang=us"},{"id":67204,"title":"Spectral Doppler (ultrasound)","link":"/articles/spectral-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\u003eWhich of the following will increase the maximum velocity a pulse wave Doppler machine is able to accurately detect?\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/2830"}],"attemptsPercentages":[{"alternativeId":"13812","percentage":35},{"alternativeId":"13813","percentage":15},{"alternativeId":"13814","percentage":7},{"alternativeId":"13810","percentage":26},{"alternativeId":"13811","percentage":17}],"promptToLogin":false,"questionManager":false,"articleId":"doppler-shift"}