Siemens MULTI-ECHO EPI 4A21 Installation And User's Manual

[Page 1] Siemens MULTI-ECHO EPI 4A21

Works-in-Progress package Version 2.0 For the SIEMENS Magnetom under VA21B Installation and User’s Guide NUMARIS/4A21 April 4th, 2003 Section of Medical Physics, University Hospital Freiburg, Germany Contact: ...

[Page 2] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 2 of 9 Numaris/4 VA21B Table of Contents 1 Basic principles ................................................................................................. 3 1.1 Principle of Multi-Echo EPI.................................

[Page 3] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 3 of 9 Numaris/4 VA21B 1 Basic principles 1.1 Principle of Multi-Echo EPI The basic timing scheme of Multi-Echo EPI is shown in Figure 1. It is based on the original EPI sequence proposed by Mansfield (1). After a si...

[Page 4] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 4 of 9 Numaris/4 VA21B 1.2 Image contrast of Multi-Echo EPI The signal intensity of the single echo images of the Multi-Echo EPI sequence is simply given by: *)2/exp(0 TTESS −= where S0 is the signal intensity at ...

[Page 5] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 5 of 9 Numaris/4 VA21B 3. O. Speck, T. Ernst, L. Chang. Bi-exponential modeling of multi gradient echo data of the brain. Magn. Reson. Med. 45(6), 1116-1121 (2001) 4. O. Speck, J. Hennig. Motion Correction of Parametric fMR...

[Page 6] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 6 of 9 Numaris/4 VA21B ...

[Page 7] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 7 of 9 Numaris/4 VA21B 3 Sequences and Protocols 3.1 General Remarks Since the sequence is derived from the standard EPI sequence, most of the user interface and features are identical to this method. Due to the large n...

[Page 8] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 8 of 9 Numaris/4 VA21B Separate Correction: In the source code of the sequence card a new parameter ‘Separate Correction’ has been introduced. If this parameter is enabled (during compilation) each echo image is precede...

[Page 9] Siemens MULTI-ECHO EPI 4A21

Multi-Echo EPI Page 9 of 9 Numaris/4 VA21B t-Test: The online t-test and display work as in the original EPI sequence. However, the t-test only works properly when motion correction is selected! Alternatively, T2*-Maps can be processed within th...