Question 2962
{"accessible":false,"alternatives":[{"id":14419,"text":"gradient echo echo planar imaging (GE EPI)"},{"id":14420,"text":"multiecho spin echo imaging"},{"id":14421,"text":"short TR gradient echo imaging"},{"id":14422,"text":"spin echo echo planar imaging (SE EPI)"}],"archived":false,"correctAlternativeId":14422,"explanation":"\u003cp\u003eSpin echo EPI is ideal for diffusion weighted imaging for the following reasons:\u003c/p\u003e\u003cul\u003e\n\u003cli\u003e\u003cp\u003eSignal is acquired rapidly\u003c/p\u003e\u003c/li\u003e\n\u003cli\u003e\u003cp\u003eSpin echo accounts for signal loss secondary to magnetic field non-uniformity\u003c/p\u003e\u003c/li\u003e\n\u003cli\u003e\u003cp\u003eThe time between the 90 and 180 degree radiofrequency pulses is used for application of the diffusion gradient pulses\u003c/p\u003e\u003c/li\u003e\n\u003cli\u003e\u003cp\u003eIt can be used in combination with chemical shift selective sequences or inversion recovery sequences to null fat signal\u003c/p\u003e\u003c/li\u003e\n\u003c/ul\u003e\u003cp\u003eGradient echo sequences don't allow for the application of the diffusion gradients.\u003c/p\u003e\u003cp\u003eMultiecho spin-echo imaging is rarely used in clinical MRI (the need for proton density weighted images in the brain has reduced since FLAIR has become available).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e","id":2962,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2962","nextQuestionPath":"/articles/diffusion-weighted-imaging-2/questions/2961","relatedArticles":[{"id":22136,"title":"Spin echo sequences","link":"/articles/spin-echo-sequences?lang=us"},{"id":19116,"title":"Echo planar imaging","link":"/articles/echo-planar-imaging-1?lang=us"},{"id":18339,"title":"Gradient echo sequences","link":"/articles/gradient-echo-sequences-1?lang=us"},{"id":22558,"title":"MRI physics","link":"/articles/mri-physics?lang=us"},{"id":60745,"title":"Fast spin echo","link":"/articles/fast-spin-echo?lang=us"}],"alsoUsedIn":[{"id":1928,"kind":"Course","title":"Imaging Physics: MRI - page 1928","link":"https://radiopaedia.org/courses/imaging-physics-mri/pages/1928"}],"stem":"\u003cp\u003eWhich of the following sequences is predominantly used in diffusion weighted imaging (DWI)?\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/2962"}],"attemptsPercentages":[{"alternativeId":"14422","percentage":45},{"alternativeId":"14421","percentage":15},{"alternativeId":"14420","percentage":8},{"alternativeId":"14419","percentage":31}],"promptToLogin":false,"questionManager":false,"articleId":"diffusion-weighted-imaging"}