Question 2966
{"accessible":false,"alternatives":[{"id":14437,"text":"long TE, long TR"},{"id":14438,"text":"long TE, short TR"},{"id":14439,"text":"short TE, long TR"},{"id":14440,"text":"short TE, short TR"}],"archived":false,"correctAlternativeId":14440,"explanation":"\u003cp\u003eMost commonly, a 3D T1-weighted incoherent gradient echo sequence is used for CE MRA.\u003c/p\u003e\u003cp\u003eAt high concentrations, gadolinium drastically reduces the T1 constant in tissues. A \u003cstrong\u003e\u003cem\u003eshort TR \u003c/em\u003e\u003c/strong\u003ewill prevent tissues with long T1 constants from regaining much longitudinal magnetization. Tissues with high concentrations of gadolinium will regain longitudinal magnetization prior to the TR (because of the drastic reduction in T1) and appear bright on the image.\u003c/p\u003e\u003cp\u003eGadolinium also reduces T2. Therefore, transverse signal must be captured quickly after the radiofrequency pulse is turned off. This necessitates a \u003cstrong\u003e\u003cem\u003eshort TE\u003c/em\u003e\u003c/strong\u003e.\u003c/p\u003e","id":2966,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2966","nextQuestionPath":null,"relatedArticles":[{"id":14587,"title":"Echo time","link":"/articles/echo-time?lang=us"},{"id":14588,"title":"Repetition time","link":"/articles/repetition-time?lang=us"},{"id":18476,"title":"MR angiography","link":"/articles/mr-angiography-2?lang=us"},{"id":18338,"title":"Contrast-enhanced MR angiography","link":"/articles/contrast-enhanced-mr-angiography-1?lang=us"},{"id":22558,"title":"MRI physics","link":"/articles/mri-physics?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 combination of sequence parameters is usually best for contrast enhanced MR angiography (CE MRA)?\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/2966"}],"attemptsPercentages":[{"alternativeId":"14439","percentage":13},{"alternativeId":"14438","percentage":9},{"alternativeId":"14440","percentage":71},{"alternativeId":"14437","percentage":8}],"promptToLogin":false,"questionManager":false,"articleId":"spoiled-gradient-echo-mri"}