Analisis Penggunaan Semac Dalam Mereduksi Artefak Pada MRI Dengan Metal Prothesis

Background: The need to display lesions close to the area where orthopaedic implants are placed requires the use of metal artefact reduction techniques with optimal examination time. The presence of metal implants in MRI can cause substantial image artefacts, including signal loss, fat suppression failure, geometric distortion, and hyperintense signal pile up artefacts. This leads to large resonant frequency changes and failure of many MRI mechanisms. SEMAC or Slice Encoding Metal Artefact Correction is a sequence or algorithm to reduce metal artefacts caused by implant magnetic susceptibility but the acquisition time is quite long The need to display lesions close to the area where orthopaedic implants are placed requires the use of metal artefact reduction techniques with optimal examination time. The presence of metal implants in MRI can cause substantial image artefacts, including signal loss, fat suppression failure, geometric distortion, and hyperintense signal pile up artefacts. This leads to large resonant frequency changes and failure of many MRI mechanisms. SEMAC or Slice Encoding Metal Artefact Correction is a sequence or algorithm to reduce metal artefacts caused by implant magnetic susceptibility but the acquisition time is quite long..Methods: This research applies an analysis qualitative descriptive method using a phantom approach with a metal prosthesis type SS 316L executed at Fatmawati Central General Hospital in October 2023. As for the population used, it is phantom with a sample of 18 patents. Data collection methods are namely observation and interviews. The research instruments were observation sheets and interview guidelines.Results:The analysis results show that signal loss artefacts are still quite extensive and interfere with the image, signal loss can be reduced by increasing the SES value. Signal pile up artefacts are few and do not disturb the image. The implant edge structure cannot be visualised close to the original shape because the artefacts are quite extensive and distorted in the implant area.Conclusions:The SEMAC sequence with the selection of SES values of 6, 10 or 15 is one way to reduce metal artefacts and can be combined with grappa to shorten the acquisition time.