Study of Diffusion Weighted Imaging in Magnetic Resonance Imaging: Quantification of Apparent Diffusion Coefficient (ADC) from b-value in Agarose

Diffusion Magnetic Resonance Imaging (MRI) is one of the promising methods to observe molecular structure and diffusion properties of materials and tissues inside human body. The experiments with diffusion MRI had been conducted on 11 agarose gel inside tubes with the solution percentages of 0% - 5% with an increment of 0.5% to obtain apparent diffusion coefficient (ADC) of agarose gel. Images were acquired using 1.5 Tesla MRI machine with a spin-echo sequence. The parameters used are TR 5000 ms, TE 50 ms, b-value with variations of (10, 50, 75, 125, 250, 500, 750, and 1000) s/mm2, slice thickness 5 mm and field of view 36 mm × 36 mm. Image processing was carried out using ImageJ software to determine the average signal intensity for each sample. After signal intensities from all variations of b-value were obtained, the linear curve fitting with b-value was performed using Matlab to obtain ADC. From the experimental results, it is found that the signal intensity decreases with increasing b-value and ADC of agarose gel is not linearly proportional to agarose concentration.