{"action":"created","issue":{"url":"https://api.github.com/repos/firasm/CEST/issues/41","labels_url":"https://api.github.com/repos/firasm/CEST/issues/41/labels{/name}","comments_url":"https://api.github.com/repos/firasm/CEST/issues/41/comments","events_url":"https://api.github.com/repos/firasm/CEST/issues/41/events","html_url":"https://github.com/firasm/CEST/issues/41","id":85302778,"number":41,"title":"Mouse Brain - Long Saturation Pulse (4s), Accelerated (72x) spectra","user":{"login":"firasm","id":2507459,"avatar_url":"https://avatars.githubusercontent.com/u/2507459?v=3","gravatar_id":"","url":"https://api.github.com/users/firasm","html_url":"https://github.com/firasm","followers_url":"https://api.github.com/users/firasm/followers","following_url":"https://api.github.com/users/firasm/following{/other_user}","gists_url":"https://api.github.com/users/firasm/gists{/gist_id}","starred_url":"https://api.github.com/users/firasm/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/firasm/subscriptions","organizations_url":"https://api.github.com/users/firasm/orgs","repos_url":"https://api.github.com/users/firasm/repos","events_url":"https://api.github.com/users/firasm/events{/privacy}","received_events_url":"https://api.github.com/users/firasm/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-06-04T22:18:03Z","updated_at":"2015-06-05T02:16:44Z","closed_at":null,"body":"mouse study name: 'cest_FM.w01'\r\n\r\nThis is the result from today's brain experiment that Barry and @srveale did for us. @DrSAR, @andrewcyung, and I got some ideas on things to try from some people we've talked to and we were impatient so we thought we'd get started.\r\n\r\nWhat we mean by accelerating of 72x, is that for 72 phase encodes, only one saturation pulse was used. The \"delay\" in the plot below refers to the waiting time between subsequent saturation pulses (in this case, equivalent to subsequent frequency offsets).\r\n\r\nThis is still the first mouse, the second mouse is currently being imaged.\r\n\r\n![unknown-2](https://cloud.githubusercontent.com/assets/2507459/7995349/09b42372-0ae3-11e5-8918-41e33a505492.png)\r\n\r\nFor reference, here is the CEST spectrum for the non-accelerated scan (one sat pulse per k-space line) with a 4s pulse length. I've actually shown two reference datasets, one with a low FA (5) and one with a high FA (80) to demonstrate the importance of SNR in the CEST Spectrum. You'll notice that the images look comparable but in reality aren't and the spectra show the noise\r\n\r\n![unknown-3](https://cloud.githubusercontent.com/assets/2507459/7995643/efc29496-0ae5-11e5-8e8d-cf744ebf72a2.png)\r\n\r\nThe main questions this poses/solves:\r\n\r\n1. InterSaturationFreq Delay doesn't seem to matter, so we will likely ditch it.\r\n1. Long Pulse length seems to result in CEST peaks around 3.5 ppm\r\n1. Outstanding question is: how many peaks are there!?\r\n1. It *does* seem to make a difference whether you do linear offsets or alternating offsets, but the question is which one is the correct one to do? The linear offsets results in 3 (!) discernible peaks around 3.5 ppm whereas the alternating offsets results in a single (maybe 2?) broad peak\r\n1. If you have a long sat pulse (4s) before each k-space line, your CEST signal disappear!? Why !?!?\r\n\r\nThe plot thickens... "},"comment":{"url":"https://api.github.com/repos/firasm/CEST/issues/comments/109132150","html_url":"https://github.com/firasm/CEST/issues/41#issuecomment-109132150","issue_url":"https://api.github.com/repos/firasm/CEST/issues/41","id":109132150,"user":{"login":"andrewcyung","id":1995950,"avatar_url":"https://avatars.githubusercontent.com/u/1995950?v=3","gravatar_id":"","url":"https://api.github.com/users/andrewcyung","html_url":"https://github.com/andrewcyung","followers_url":"https://api.github.com/users/andrewcyung/followers","following_url":"https://api.github.com/users/andrewcyung/following{/other_user}","gists_url":"https://api.github.com/users/andrewcyung/gists{/gist_id}","starred_url":"https://api.github.com/users/andrewcyung/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/andrewcyung/subscriptions","organizations_url":"https://api.github.com/users/andrewcyung/orgs","repos_url":"https://api.github.com/users/andrewcyung/repos","events_url":"https://api.github.com/users/andrewcyung/events{/privacy}","received_events_url":"https://api.github.com/users/andrewcyung/received_events","type":"User","site_admin":false},"created_at":"2015-06-05T02:16:44Z","updated_at":"2015-06-05T02:16:44Z","body":"Hi guys, here are the cest spectra WITHOUT normalization:\r\n\r\n[cid:image001.png@01D09EFA.F40ED610]\r\nYou can see that the signal range is so, so much wider for FA=80 degrees as opposed to FA=5 degrees.  I noticed that the 5 degree flip angle has an attenuator value of 39.5 dB.  Could we be in the range where the digital resolution of the attenuation is insufficient to give us the proper flip angle?  It’s a gauss pulse which has some of the lowest peak amplitudes.\r\n\r\n\r\n\r\nFrom: DrSAR [mailto:notifications@github.com]\r\nSent: Thursday, June 04, 2015 3:48 PM\r\nTo: firasm/CEST\r\nCc: Yung, Andrew\r\nSubject: Re: [CEST] Mouse Brain - Long Saturation Pulse (4s), Accelerated (72x) spectra (#41)\r\n\r\n\r\nWhy do you say, the CEST signal disappears for long sat pulses (4s). I presume I am to look at the CEST-no acc-high FA(80) panel? I think there is still a peak there, no?\r\n\r\n—\r\nReply to this email directly or view it on GitHub<https://github.com/firasm/CEST/issues/41#issuecomment-109076031>.\r\n"}}