T2∗ Relaxation of Agar Gel with and Without the Presence of Tumor-Like Structure as Obtained from Resting State Fmri Sequence Protocol

Ahmad Nazlim Yusoff, N. S. Abdul Rashid, S. Usman Ali

Research output: Contribution to journalConference article

Abstract

The objective of this study was to determine the change in signal-to-noise ratio (SNR) as a function of TE of agar gel phantom with and without the presence of tumor-like structure, using a resting state fMRI sequence protocol. The phantoms were prepared using a conventional method. Citrus hystrix DC (kaffir lime) was used to mimick tumor and was submerged in the agar gel. The phantoms were scanned using a 3T-MRI system. An rsfMRI sequence protocol (TR = 2000 ms; TE = 51 ms - 115 ms) was used in obtaining the SNR at several TEs. In addition, a standard MRI phantom as control was also scanned using the same sequence protocol. For the prepared phantoms, the SNR was obtained from several 7-mm diameter ROIs at a distance 2, 4 and 6 cm from the centre of the image and was averaged. For the standard MRI phantom, similar ROI diameter was used for SNR determination but for three different slice thickneses; 3, 5 and 10 mm. The MRI, agar gel and agar gel with kaffir lime phantoms show T2∗ relaxation that fits the exponential equation S ∝ e-TE/T2∗. The average T2∗ for the standard MRI phantom is 86.7 ± 0.1 ms. The average T2∗ for agar gel phantom is 70.1 ± 0.1 ms while T2∗ is shortened to an average of 54.8 ± 0.1 ms for agar gel phantom with kaffir lime. This indicate an increase in local magnetic field inhomogeneity in the vicinity of the tumor. The relaxation is thus faster causing a drop in the magnetic resonance signal intensity. The agar gel and agar gel with tumor mimicking phantom are suitable for a long TE rsfMRI scans.

Original languageEnglish
Article number012017
JournalJournal of Physics: Conference Series
Volume1083
Issue number1
DOIs
Publication statusPublished - 10 Sep 2018
Event6th International Conference of Solid State Science and Technology and Workshop on Advanced Materials Technology: Growth and Characterization, ICSSST AMTGC 2017 - Penang, Malaysia
Duration: 13 Nov 201716 Nov 2017

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tumors
gels
calcium oxides
signal to noise ratios
magnetic resonance
inhomogeneity
direct current
magnetic fields

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

T2∗ Relaxation of Agar Gel with and Without the Presence of Tumor-Like Structure as Obtained from Resting State Fmri Sequence Protocol. / Yusoff, Ahmad Nazlim; Abdul Rashid, N. S.; Usman Ali, S.

In: Journal of Physics: Conference Series, Vol. 1083, No. 1, 012017, 10.09.2018.

Research output: Contribution to journalConference article

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