Aalia Nazir, Muhammad Afzal Rao, Saeed Ahmad Buzdar.
Effects of variation of MRI parameters on signal homogeneity: a qualitative analysis for ferrous benzoic xylenon orange gel.
J Pak Med Assoc Jan ;65(6):470-3.

Objective: This study focuses on the diverse effects of MRI parameters on image quality using widely available imaging pulse sequences. Methods: A tissue equivalent gel system has been used for Magnetic Resonance Imaging by using Xylenol orange dye with Fricke-Benzoic solution which was formulated by Kelly R.G (1998). The gel system was radiated while using 6MV photons from Varian Clinic Linear Accelerator. Results: The qualitative analysis include the effect of TR and TE on signal nonuniformity according to which the escalating repetition time gives a uniform signal having the average values calculated are 0.76%, 0.83%, 1.43% and 1.89% for the conventional spin echo (CSE), fast spin echo (FSE), gradient recalled echo (GRE) and fluid attenuated inversion recovery (FLAIR) respectively. FLAIR showed contradictory results due to longitudinal relaxation of the signal. This is because, at the longer value of inversion time (TI), the signal from simple fluids is nulled, thus reducing signal intensity. Conclusion: The evaluation of signal uniformity for different pulse sequences demonstrates that the repetition time (TR) affects the signal homogeneity as it maintains image quality for CSE and FSE. However, a careful selection is required for FLAIR due to its sensitive behaviour for image uniformity (JPMA 60:470; 2010).

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