모형을 이용한 1.5T와 3.0T 자기공명에서의 뇌 대사물질들의 수소 T1과 T2 이완시간의 비교
Comparison of Proton T1 and T2 Relaxation Times of Cerebral Metabolites between 1.5T and 3.0T MRI using a Phantom
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목적 : 주요 뇌 대사물질들의 T1 및 T2 이완시간들을 1.5T 및 3.0T 자기공명영상에서 산출하고 비교하여, 실제 임상응용의 기초자료로 제시하고자 하였다. 대상 및 방법 : 1.5T와 3.0T에서 N-acetyl aspartate (NAA), Choline (Cho), Creatine (Cr)을 함유한 모형을 이용하여 STEAM (STimulated Echo-Acquisition Mode)방법으로 반복시간 (Repetition time)을 5000 ms, 에코시간 (Echo time)을 20 ms로 고정한 후 혼합시간 (Mixing time)을 11단계로 변화시켜서 획득된 스펙트럼들에서 뇌 대사물질들의 T1 이완시간을 산출하였으며, PRESS (Point-REsolved SpectroScopy)방법으로 반복시간을 3000 ms에 고정시킨 후 에코시간을 5단계로 변화시켜서 획득된 스펙트럼들에서 뇌 대사물질들의 T2 이완시간을 산출한 후 그 결과들을 1.5T와 3.0T사이에서 비교하였다. 결과 : T1 이완시간에 대하여, NAA는 1.5T에서 2293 ± 48 ms, 3.0T에서 2559 ± 124ms로 산출되어 1.5T와 비교하여 3.0T에서 11.6% 길어졌고, Cho은 1.5T에서 2540 ± 57ms, 3.0T에서 2644 ± 76 ms로 3.0T에서 4.1% 길어졌으며, Cr 은 1.5T에서 2543 ± 75ms, 3.0T에서 2665 ± 94 ms로 3.0T에서 4.8% 길어졌다. T2 이완시간에 대하여, NAA는 1.5T에서 526 ± 81 ms, 3.0T에서 468 ± 74 ms로 산출되어 3.0T에서 11.0% 짧아졌고, Cho 은 1.5T에서 220 ± 44 ms, 3.0T에서 182 ± 35 ms로 3.0T에서 17.3% 짧아졌으며, Cr 은 1.5T에서 289 ± 47 ms, 3.0T에서 275 ± 57 ms로, 3.0T에서 4.8% 짧아졌다. 결론 : 1.5T와 비교하여 3.0T에서 모형에 함유된 주요 뇌 대사물질들의 T1이완시간들은 4.1% ~ 11.6% 증가하였고, T2이완시간들은 4.8% ~ 17.3% 감소하였으므로, 자기공명분광법의 적정화를 위하여 3.0T에서 반복시간을 연장시키고, 에코시간은 단축시켜야 한다.
Abstract
Purpose : To present the T1 and T2 relaxation times of the major cerebral metabolites at 1.5T and 3.0T and compare those between 1.5T and 3.0T. Materials and Methods : Using the phantom containing N-acetyl aspartate (NAA), Choline (Cho), and Creatine (Cr) at both 1.5T and 3.0T MRI, the T1 relaxation times were calculated from the spectral data obtained with 5000 ms repetition time (TR), 20 ms echo time (TE), and 11 different mixing time (TM)s using STEAM (STimulated Echo-Acquisition Mode) method. The T2 relaxation times were obtained from the spectral data obtained with 3000 ms TR and 5 different TEs using PRESS (Point-RESolved Spectroscopy) method. The T1 and T2 relaxation times obtained at 1.5T were compared with those of 3.0T. Results : The T1 relaxation times of NAA were 2293 ± 48 ms at 1.5T and 2559 ± 124 ms at 3.0T (11.6% increase at 3.0T). The T1 relaxation times of Cho were 2540 ±57 ms at 1.5T and 2644 ± 76 ms at 3.0T (4.1% increase at 3.0T). The T1 relaxation times of Cr were 2543 ± 75 ms at 1.5T and 2665 ± 94 ms at 3.0T (4.8% increase). The T2 relaxation times of NAA were 526 ± 81 ms at 1.5T and 468 ±74 ms at 3.0T (11.0% decrease at 3.0T). The T2 relaxation times of Cho were 220 ± 44ms at 1.5T and 182 ± 35 ms at 3.0T (17.3% decrease at 3.0T). The T2 relaxation times of Cr were 289 ± 47 ms at 1.5T and 275 ± 57 ms at 3.0T (4.8% decrease at 3.0T). Conclusion : The T1 relaxation times of the major cerebral metabolites (NAA, Cr, Cho), which were measured at the phantom, were 4.1%-11.6% longer at 3.0T than at 1.5T. The T2 relaxation times of them were 4.8%-17.3% shorter at 3.0T than at 1.5T. To optimize MR spectroscopy at 3.0T, TR should be lengthened and TE should be shortened.
참고문헌 (9)
- Barker PB, "Single-voxel proton MRS of the human brain at 1.5T and 3.0T", Magn Reson Med, 45, pp.765~769 (2001)
- Gonen O, "Multivoxel 3D proton spectroscopy in the brain at 1.5 versus 3.0 T: signalto- noise ratio and resolution comparison", AJNR Am J Neuroradiol, 22, pp.1727~1731 (2001)
- Kantarci K, "AJNR Am J Neuroradiol", AJNR Am J Neuroradiol, 24, pp.843~849 (2003)
- Ethofer T, "Comparison of longitudinal metabolite relaxation times in different regions of the human brain at 1.5 and 3 Tesla", Magn Reson Med, 50, pp.1296~1301 (2003)
- Mlynarik V, "Proton T(1) and T(2) relaxation times of human brain metabolites at 3 Tesla", NMR Biomed, 14, pp.325~331 (2001)
- Traber F, "1H Metabolite Relaxation Times at 3.0 Tesla: Measurements of T1 and T2 Values in normal brain and determination of regional differences in transverse relaxation", J Magn Reson Imagi, 19, pp.537~545 (2004)
- de Bazelaire CM, "MR imaging relaxation times of abdominal and pelvic tissues measured in vivo at 3.0 T: preliminary results", Radiology, 230, pp.652~659 (2004)
- Brief EE, "Proton T1 relaxation times of cerebral metabolites differ within and between regions of normal human brain", NMR Biomed, 16, pp.503~509 (2003)
- Kelley DA, "Lactate detection at 3T: compensating J coupling effects with BASING", J Magn Reson Imaging, 9, pp.732~737 (1999)