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Title: Determination of NMR relaxation times (T1 and T2) from multislice, multiecho MR imaging

Abstract

In proton MR imaging the determination of fundamental MR constants such as spin lattice (T1) and spin spin (T2) relaxation times is essential for an understanding of image contrast and for insight into the question of optimal field vis a vis disease state. Multislice, multiecho imaging is attractive because imaging time per slice is reduced; however, slice selecting radiofrequency (RF) pulses may cause interference from adjacent slices to the slice being imaged. This interference will cause incorrect relaxation time measurements and ''false'' image contrast between tissues which could result in improper diagnosis. To observe the effect of slice separation on T1 and T2 the authors imaged bottles of various concentrations of MnCl/sub 2/, with T1 values ranging from 215 to 1003 msec and T2 values from 39 to 240 msec. For T1 determinations two sets of multi-slice images (5 slices with nominal thickness of 1 cm) were taken both with an echo time (TE) of 30 msec and repetition times (TR) of 500 and 2000 msec. Slice separation was varied from 0 to 1 cm in 0.25 cm intervals. Reliable T1 values were obtained only when the slice separation was 0.75 or 1 cm. When slice separation was less thanmore » this, the TR500 images showed severe reversals in expected contrast when outside slices were compared with central slices. The effect of slice separation on T2 relaxation was investigated using a 5 slice multiecho technique (8 echoes per slice) with TR of 1400 msec and TE varying from 30 to 240 msec in intervals of 30 msec and nominal thickness set at 1 cm. Acquisitions were taken for slice separations from 0 to 1 cm and accurate T2 values for all 5 slices were only obtained when slice separation was 1 cm.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Institute and Nuclear Medicine Dept., St. Joseph's Hospital and Univ. of Western Ontario, London
OSTI Identifier:
6639329
Report Number(s):
CONF-850611-
Journal ID: CODEN: JNMEA
Resource Type:
Conference
Journal Name:
J. Nucl. Med.; (United States)
Additional Journal Information:
Journal Volume: 26:5; Conference: 32. annual meeting of the Society of Nuclear Medicine, Houston, TX, USA, 2 Jun 1985
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; DISEASES; DIAGNOSIS; NUCLEAR MAGNETIC RESONANCE; SPIN-LATTICE RELAXATION; SPIN-SPIN RELAXATION; ACCURACY; DIAGNOSTIC TECHNIQUES; IMAGE PROCESSING; IMAGES; MANGANESE CHLORIDES; RADIOWAVE RADIATION; RELAXATION TIME; RF SYSTEMS; TIMING PROPERTIES; CHLORIDES; CHLORINE COMPOUNDS; ELECTROMAGNETIC RADIATION; HALIDES; HALOGEN COMPOUNDS; MAGNETIC RESONANCE; MANGANESE COMPOUNDS; MANGANESE HALIDES; PROCESSING; RADIATIONS; RELAXATION; RESONANCE; TRANSITION ELEMENT COMPOUNDS; 550601* - Medicine- Unsealed Radionuclides in Diagnostics

Citation Formats

Wilkins, K, Prato, F S, Drost, D J, and Keys, T. Determination of NMR relaxation times (T1 and T2) from multislice, multiecho MR imaging. United States: N. p., 1985. Web.
Wilkins, K, Prato, F S, Drost, D J, & Keys, T. Determination of NMR relaxation times (T1 and T2) from multislice, multiecho MR imaging. United States.
Wilkins, K, Prato, F S, Drost, D J, and Keys, T. 1985. "Determination of NMR relaxation times (T1 and T2) from multislice, multiecho MR imaging". United States.
@article{osti_6639329,
title = {Determination of NMR relaxation times (T1 and T2) from multislice, multiecho MR imaging},
author = {Wilkins, K and Prato, F S and Drost, D J and Keys, T},
abstractNote = {In proton MR imaging the determination of fundamental MR constants such as spin lattice (T1) and spin spin (T2) relaxation times is essential for an understanding of image contrast and for insight into the question of optimal field vis a vis disease state. Multislice, multiecho imaging is attractive because imaging time per slice is reduced; however, slice selecting radiofrequency (RF) pulses may cause interference from adjacent slices to the slice being imaged. This interference will cause incorrect relaxation time measurements and ''false'' image contrast between tissues which could result in improper diagnosis. To observe the effect of slice separation on T1 and T2 the authors imaged bottles of various concentrations of MnCl/sub 2/, with T1 values ranging from 215 to 1003 msec and T2 values from 39 to 240 msec. For T1 determinations two sets of multi-slice images (5 slices with nominal thickness of 1 cm) were taken both with an echo time (TE) of 30 msec and repetition times (TR) of 500 and 2000 msec. Slice separation was varied from 0 to 1 cm in 0.25 cm intervals. Reliable T1 values were obtained only when the slice separation was 0.75 or 1 cm. When slice separation was less than this, the TR500 images showed severe reversals in expected contrast when outside slices were compared with central slices. The effect of slice separation on T2 relaxation was investigated using a 5 slice multiecho technique (8 echoes per slice) with TR of 1400 msec and TE varying from 30 to 240 msec in intervals of 30 msec and nominal thickness set at 1 cm. Acquisitions were taken for slice separations from 0 to 1 cm and accurate T2 values for all 5 slices were only obtained when slice separation was 1 cm.},
doi = {},
url = {https://www.osti.gov/biblio/6639329}, journal = {J. Nucl. Med.; (United States)},
number = ,
volume = 26:5,
place = {United States},
year = {Wed May 01 00:00:00 EDT 1985},
month = {Wed May 01 00:00:00 EDT 1985}
}

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