Question 2791
{"accessible":false,"alternatives":[{"id":13618,"text":"fat - air"},{"id":13619,"text":"fat - bone "},{"id":13620,"text":"fat - fat"},{"id":13621,"text":"fat - muscle"}],"archived":false,"correctAlternativeId":13618,"explanation":"\u003cp\u003e\u003cstrong\u003eTransmittance = 1 - Reflection\u003c/strong\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eReflection = [(Z\u003csub\u003e2\u003c/sub\u003e-Z\u003csub\u003e1\u003c/sub\u003e)/(Z\u003csub\u003e2\u003c/sub\u003e+Z\u003csub\u003e1\u003c/sub\u003e)]\u003csup\u003e2\u003c/sup\u003e \u003c/strong\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eZ = Acoustic impedance\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eTherefore, greater differences in acoustic impedance (Z) results is more reflection and less transmittance. Of the above tissue interfaces fat and air have the greatest difference in acoustic impedance values.\u003c/p\u003e\u003cp\u003e\u003cem\u003eAcoustic impedance values (Z):\u003c/em\u003e\u003c/p\u003e\u003cp\u003eAir - 0.0004 × 10\u003csup\u003e6 \u003c/sup\u003e\u003c/p\u003e\u003cp\u003eFat - 1.34 × 10\u003csup\u003e6\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eMuscle - 1.71 × 10\u003csup\u003e6\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eBone - 7.8 × 10\u003csup\u003e6\u003c/sup\u003e\u003c/p\u003e","id":2791,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2792","nextQuestionPath":null,"relatedArticles":[{"id":32118,"title":"Acoustic impedance","link":"/articles/acoustic-impedance?lang=us"},{"id":55789,"title":"Reflection","link":"/articles/reflection?lang=us"},{"id":46913,"title":"Refraction","link":"/articles/refraction?lang=us"}],"alsoUsedIn":[{"id":1608,"kind":"RestrictedPage","title":"Page 1608 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/1608"},{"id":1972,"kind":"Course","title":"Imaging Physics: Ultrasound Peer Review - page 1972","link":"https://radiopaedia.org/courses/imaging-physics-ultrasound-peer-review/pages/1972"},{"id":1972,"kind":"Course","title":"Imaging Physics: Ultrasound - page 1972","link":"https://radiopaedia.org/courses/imaging-physics-ultrasound/pages/1972"}],"stem":"\u003cp\u003eWhich of the following tissue interfaces has the lowest transmittance value?\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/2791"}],"attemptsPercentages":[{"alternativeId":"13621","percentage":3},{"alternativeId":"13620","percentage":9},{"alternativeId":"13619","percentage":22},{"alternativeId":"13618","percentage":66}],"promptToLogin":false,"questionManager":false,"articleId":"scattering-ultrasound"}