Wide slab is useful for routine quality control of MRI slice thickness

Although slice thickness accuracy is important for the performance of magnetic resonance imaging systems, long scan times are required to perform reliable measurements. Inclined slabs and wedges are conventionally used as test devices to obtain slice profiles. In this study, a novel dedicated device with a widened slab was created, and its efficacy was compared with that of a conventional wedge. The signal-to-noise ratio (SNR) of the profile and the coefficient of variation (CV) of the measured slice thickness were measured. Wide slab usage showed sufficient SNR by averaging multiple profile lines, even with single acquisition. Therefore, it is possible to substantially shorten the measurement time. When ≥ 20 lines were averaged, CV was < 1%. Furthermore, a 200-mm slab width enabled evaluation of the positional dependence of slice thickness in a single imaging. Thus, quality control of MRI slice thickness can be easily implemented with this device.