Effect of Variation Number of Excitation (NEX) Parameter on the Quality Image of Magnetic Resonance Imaging Genu on T2 Weighted Image Sequence at Bali Mandara Regional General Hospital, Indonesia

Aim: Study on the effect of NEX parameter variations on image quality in T2WI sequences on genu MRI images aims to determine the effect of Number of Excitation (NEX) variations on image quality which is influenced by scanning time and Signal to Noise Ratio (SNR) and determine the best NEX variation to produce scanning time and SNR T2WI MRI genu. Study Design: This study used a quantitative analytic design in the form of experiments and direct field observations. This study was conducted in the MRI unit of Bali Mandara Hospital from January to December 2024. Methodology: This study involved 30 patients who underwent genu MRI examination with 3 variations of NEX values ranging from (1, 2 and 3). Evaluating the scanning time and SNR value of the tissue by measuring the ROI directly on the MRI device. Data were analyzed using IBM SPSS statistical software and Excel software to evaluate the effect of NEX variation on image quality. The MRI machine used was Philips Ingenia CX 1.5 Tesla with standard protocol parameters for imaging genu Results: Scanning time and SNR values were analyzed on ligament, bone and fat tissues. The time required for scanning time was 115 seconds, 230 seconds and 345 seconds, respectively. Sequentially, the average SNR values obtained based on the calculations performed were 6.906, 10.203 and 13.307 in ligament tissue, 81.209, 115.289 and 136.14 in bone tissue, and 106.662, 151.3 and 178.212 in fat tissue. Increasing the NEX value significantly increased the scanning time and SNR value. NEX 3 provides the highest scanning time and SNR value compared to other NEX variations. This indicates that multiple NEXs produce better image quality. Conclusion: Good MRI image quality is determined by high scanning time and SNR values. This study recommends the use of NEX 3 in genu MRI imaging protocols to improve the accuracy of clinical examinations.