Three-tesla, 3D TOF MRA and 64-MDCTA are excellent modalities with high diagnostic accuracy for evaluating unruptured intracranial aneurysms and no significant difference between them in diagnostic performance.

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The 8 ch phased array coil was useful for obtaining high quality 3T images because of its higher SNR and improved image uniformity than those obtained with conventional quadrature-type birdcage head coil.

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Purpose: We attempted to optimize scan parameters for T 1 -weighted ‰uid-attenuated inversion recovery (T 1 -FLAIR) sequence at 3 and 1.5 tesla (T) using computer simulation.Methods: We measured the T 1 and T 2 relaxation time values (T 1 v and T 2 v) of gray (GM) and white matter (WM) at 3 and 1.5T, generated computer-simulated T 1 -FLAIR (CS-T 1 -FLAIR) images using those values, and compared the simulated and actual T 1 -FLAIR images to verify the contrast reliability of our computer simulation. We mathematically and visually evaluated CS-T 1 -FLAIR images at various repetition times (TR) and echo times (TE).Results: At 3T, the measured relaxation values for GM were T 1 v, 1524 ms, and T 2 v, 85 ms, and for WM, T 1 v, 750 ms, and T 2 v, 65 ms. At 1.5T, the measured relaxation values for GM were T 1 v, 1251 ms, and T 2 v, 99 ms, and for WM, T 1 v, 623 ms, and T 2 v, 75 ms. Contrast of CS-T 1 -FLAIR and actual T 1 -FLAIR images was identical. An optimal TR of 3140 ms was determined for T 1 -FLAIR at 3T and 2440 ms at 1.5T based on mathematical evaluation. The optimal TR ranges were 2400 to 3900 ms at 3T and 1800 to 3200 ms at 1.5T based on visual assessment of CS-T 1 -FLAIR. A shorter TE provided better T 1 contrast.Conclusion: We optimized T 1 -FLAIR by focusing on its most important scan parameters using computer simulations and determined that a longer TR was suitable at 3T than at 1.5T. Our computer simulation was useful for determining the optimal scan parameters.