Instruction/ maintenance manual of the product 4A21 Siemens
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Works-in-Progress package Version 2.0 For the SIEMENS Magnetom under V A21B Installation and User’s Guid e NUMARIS/4A21 April 4t h, 2003 Section of Medic al Ph ysics , Universit y Hospit al Fre iburg, G erm any Contact: Oliver Spec k PhD, H ugstet terstr.
Multi-Echo EPI Page 2 of 9 Numaris/ 4 VA21B Table of Conte nts 1 Basic principl es ................................................................................................. 3 1.1 Principle o f Multi-Echo EPI ...................................
Multi-Echo EPI Page 3 of 9 Numaris/ 4 VA21B 1 Basic principl es 1.1 Principle of M ulti-Echo EPI The basic ti ming sche me of Multi- Echo EP I is show n in Fig ure 1. It is based on th e orig inal EPI seq uence propos ed by Mans fiel d (1). A fter a sing le RF -ex citation, n complete EPI imag es are acq uired i n a si ngl e shot.
Multi-Echo EPI Page 4 of 9 Numaris/ 4 VA21B 1.2 Image contrast of Multi-Ec ho EPI The signal intensity of the singl e echo images o f the Multi-Ech o EPI sequenc e is simply given by : *) 2 / exp( 0 T.
Multi-Echo EPI Page 5 of 9 Numaris/ 4 VA21B 3. O. Speck, T. Ernst , L. Chang . Bi-ex ponentia l modeling of multi gradient ec ho data of the brain. Mag n. Reson. M ed. 45( 6), 111 6-112 1 (2001) 4. O. Speck, J. Hennig. Motion Correction of Parametric fMRI Da ta from Mu lti- Slice Sing le-Sho t Mult i-Echo Acq uisitions, M agn.
Multi-Echo EPI Page 6 of 9 Numaris/ 4 VA21B.
Multi-Echo EPI Page 7 of 9 Numaris/ 4 VA21B 3 Sequen ces an d Pro tocol s 3.1 General Remark s Since the sequenc e i s deriv ed fro m the s tand ard EP I seq uence, most o f the user inter face and featur es ar e identical to this method .
Multi-Echo EPI Page 8 of 9 Numaris/ 4 VA21B Separate Correction : In the so urce c ode o f the sequ ence car d a n ew parameter ‘Separa te Corr ection’ has be en intr oduc ed.
Multi-Echo EPI Page 9 of 9 Numaris/ 4 VA21B t-Test : The online t-test and di splay w ork as in the ori ginal EPI sequence. How ev er, the t-test only works properly when motion correction is select ed ! Altern atively, T2*-Maps can be proc essed w ithin the B OLD -card.
An important point after buying a device Siemens 4A21 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Siemens 4A21 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Siemens 4A21 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Siemens 4A21 you will learn all the available features of the product, as well as information on its operation. The information that you get Siemens 4A21 will certainly help you make a decision on the purchase.
If you already are a holder of Siemens 4A21, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Siemens 4A21.
However, one of the most important roles played by the user manual is to help in solving problems with Siemens 4A21. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Siemens 4A21 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
