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목 적：New fast acquisition technique인 wave-CAIPIRINHA를 적용한 MPRAGE sequence를 통해 brain 의 국소병변 진단능과 화질의 변화를 알아보고자 한다.
대상 및 방법：2017년 11월 22일부터 2018년 1월 2일까지 뇌 백질 병변이 있어 본원에서 추적 검사 중인 환자 39명(남자 21명, 여자 18명, 평균연령 54.9세)을 대상으로 conventional 3D T1 MPRAGE와 wave- CAIPI R(reduction factor) 6(3 × 2), wave-CAIPI R(reduction factor) 4(2 × 2) 기법으로 영상을 획득하였다. 전신용 3.0T MRI(Skyra, SIEMENS, Erlangen, Germany), 64 channel head coil을 사 용하였고, 모든 sequence는 sagittal로 촬영하였으며 interpolation은 적용하지 않았다. Conventional 3D T1 MPRAGE의 scan parameter는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 2.98 ms, TI: 1100 ms, PAT mode: GRAPPA, Accel. factor: PE 2였고, wave-CAIPI MPRAGE R6에서는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 3, 3D(slice) 2였으며, wave-CAIPI MPRAGE R4에서는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 2, 3D(slice)2였다. 획득한 영상은 medical image viewing solution(Terarecon, ver4.4.12, Foster City, USA)을 이용하여 axial reconstruction하였고, corona radiator, pons 그리고 cerebellar hemispheres에서 SNR과 CNR을 측정하였다. 정성적 평가 는 PACS(marotech, ver5.4.10.68, seoul, Korea)로 전송된 영상을 영상의학과 전문의 1명이 국소 병변에 대한 각 sequence 간의 진단능을 평가하였고, image quality는 영상의학과 전문의 1명과 MRI실 업무경력 10년 이상의 방사선사 1명이 blind test로 평가하였다. 정량적 평가의 통계적 검증은 Microsoft Excel 2010을 이용하여 ANOVA test를 하였다.
결 과：Conventional 3D T1 MPRAGE, wave-CAIPI R6 그리고 wave-CAIPI R4, 3개의 sequence 별로 측정한 SNR의 평균값은 Corona radiator에서 각각 160.08 ± 53.52, 185.56 ± 46.5 그리고 186.12 ± 48.44이었고, pons에서는 165.12 ± 43.41, 190.5 ± 46.24 그리고 190.94 ± 45.92이었으며, cerebellar hemispheres에서는 173.85 ± 52.67, 187.21 ± 52.13 그리고 191.92 ± 54.7이었다. Corona radiator 에서 GM(gray matter)과 WM(white matter)의 CNR 평균값은 conventional 3D T1 MPRAGE에서 52.39 ± 20.62였고 wave-CAIPI R6에서는 58.54 ± 18.32였으며 wave-CAIPI R4에서는 57.58 ± 21.11로 Conventional 3D T1 MPRAGE에 비해 wave-CAIPI R6, R4에서 SNR과 CNR이 약간 높았 다. 3 sequence 간의 focal lesion diagnosis에 대한 정성적 평가에서 100% agreement를 보였으며, image quality에 대한 평가에서 conventional 3D T1 MPRAGE에서 평균 4.85 ± 0.37, wave- CAIPI R6에서 3.82 ± 0.56, wave-CAIPI R4에서 4.10 ± 0.55 이었고 통계적 유의하였다(p≤0.05). 영상 획득 시간은 conventional 3D T1 MPRAGE는 5:48s였고 wave-CAIPI R6에서는 1:52s였으며 wave-CAIPI R4는 2:44s로, conventional 3D T1 MPRAGE에 비해 각각 67.8%, 52.8% 감소하였다.
결 론：Conventional 3D T1 MPRAGE에 비해 wave-CAIPI MPRAGE기법은 image quality의 저하 없이 scan time을 획기적으로 줄일 수 있어 임상적으로 유용할 것으로 사료된다.
Pulpose：To investigate wave-CAIPIRINHA loaded MPRAGE that new_fast acquisition technique how useful of diagnosis performance and image quality of the brain.
Materials and Methods：From November 22, 2017 to January 2, 2018, we have been able to conduct a follow-up examination on 39 patients (21 males, 18 females, average age 54.9) who had brain white matter lesions. Three sequences scanned that was conventional 3D T1 MPRAGE, wave-CAIPI R(reduction factor) 6(3 × 2) and wave-CAIPI R(reduction factor) 4(2 × 2). The used equipment was 3.0T MRI(Skyra, SIEMENS, Erlangen, Germany), 64 channel head coil, and not applied interpolation, perform sagittal orientation. Conventional 3D T1 MPRAGE scan parameter is 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 2.98 ms, TI: 1100 ms, PAT mode: GRAPPA, Accel. factor: PE 2, wave-CAIPI MPRAGE R6 is 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 3, 3D(slice) 2, and wave-CAIPI MPRAGE R4 is 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 2, 3D(slice)2. The acquired images were reconstruct to axial orientation(Terarecon, ver 4.4.12, Foster City, USA), SNR and CNR were measured in corona radiators, pons, and cerebellar hemispheres. To qualitative assessment, images transmit to PACS(marotech, ver 5.4.10.68, seoul, Korea) were evaluated as sequence of local lesion by a radiologist and radiological technologists. The statistical verification of quantitative assessments was done an ANOVA test using Microsoft Excel 2010. Results：The mean value of the SNR measured from the Corona radiator, pons and cerebellar hemispheres was 160.08 ± 53.52, 165.12 ± 43.41 and 173.85 ± 52.67 in conventional 3D T1 MPRAGE, wave-CAIPI R6 was 185.56 ± 46.5, 190.5 ± 46.24, and 187.21 ± 52.13, wave-CAIPI R4 was 186.12 ± 48.44, 190.94 ± 45.92 and 191.92 ± 54.7. In the Corona radiator, the average of CNR between gray and white matter was 52.39 ± 20.62 in conventional 3D T1 MPRAGE, wave-CAIPI R6 was 58.54 ± 18.32, wave-CAIPI R4 was 57.58 ± 21.11. SNR and CNR were similar in wave-CAIPI R6, R4 and MPRAGE. Qualitative assessment of the focus lesion diagnosis between requests shows 100 % agreement, and statistical attention (p ≤ 0.05). Image acquisition time is conventional 3D T1 MPRAGE was 5:48s, wave-CAIPI R6 was 1:52s, wave-CAIPI R4 was 2:44s, compared to the conventional 3D T1 MPRAGE, it shortened 67.8% and 52.8%, respectively. Conclusion：Compared to the conventional 3D T1 MPRAGE, wave-CAIPIRINHA MPRAGE techniques consider useful clinically, as they significantly reduce scan time without deteriorate image quality.
