Evaluation of slice thickness and inter slice distance in MR scanning using designed test tool

Abstract

Materials & Methods : A Test Tool Phantom was designed and kept in Heat RF coil to be studied under sequences to evaluate the concerned parameter. An imaging sequence with specified slice thickness and inter slice distance was programmed for imaging purpose. After acquisition of the sequence, the obtained image was evaluated for FW (Full width at half maxima) using the image intensity profile measurement. The evaluated FWHM was correlated with the slice thickness and compared it with set value. To evaluate the interslice distance same test tool was used with three more image slices and the slice position with respect to the origin was evaluated with distance measurement protocol in the system. The difference between tow consecutive slice positions corresponds the interslice distance. The whole measurement was performed on Siemens magnetom Vision Plus MRI System using the designed test tool. Results : Evaluated Slice Thickness and interslice distance were compare with the set valued in the programmed sequences and the variation found were under ± 1 mm. Conclusion : The designed tool can serve the purpose of routine Quality Assurance in MRI and the slice thickness parameter can be evaluated very easily. The designed test toll fulfills the criteria of task group of AAPM.