Improving acute demyelinating lesion detection: which T1-weighted magnetic resonance acquisition is more sensitive to gadolinium enhancement?

ABSTRACT Because of the need for a standardized and accurate method for detecting multiple sclerosis (MS) inflammatory activity, different magnetic resonance (MR) acquisitions should be compared in order to choose the most sensitive sequence for clinical routine. Objective To compare the sensitivity of a T1-weighted image to a single dose of gadolinium (Gd) administration both with and without magnetization transfer to detect contrast enhancement in active demyelinating focal lesions. Methods A sample of relapsing-remitting MS patients were prospectively examined separately by two neuroradiologists using a 1.5 Tesla scanner. The outcome parameters were focused on Gd-enhancement detection attributed to acute demyelination. All MR examinations with at least one Gd-enhancing lesion were considered positive (MR+) and each lesion was analyzed according to its size and contrast ratio. Results Thirty-six MR examinations were analyzed with a high inter-observer agreement for MR+ detection (k coefficient > 0.8), which was excellent for the number of Gd-enhancing lesions (0.91 T1 spin-echo (SE), 0.88 T1 magnetization transfer contrast (MTC) sequence and 0.99 magnetization-prepared rapid acquisition with gradient-echo (MPRAGE). Significantly more MR+ were reported on the T1 MTC scans, followed by the T1 SE, and MPRAGE scans. Confidently, the T1 MTC sequence demonstrated higher accuracy in the detection of Gd-enhancing lesions, followed by the T1 SE and MPRAGE sequences. Further comparisons showed that there was a statistically significant increase in the contrast ratio and area of Gd-enhancement on the T1 MTC images when compared with both the SE and MPRAGE images. Conclusion Single-dose Gd T1 MTC sequence was confirmed to be the most sensitive acquisition for predicting inflammatory active lesions using a 1.5 T magnet in this sample of MS patients.

【摘要】 由于需要标准化且精准的多发性硬化症（multiple sclerosis, MS）炎症活动检测方法，需对不同磁共振（magnetic resonance, MR）采集序列进行对比，以筛选出临床常规应用中灵敏度最高的序列。目的 对比T1加权成像（T1-weighted image）在使用与未使用磁化传递技术、单次注射钆（gadolinium, Gd）的情况下，检测活动性脱髓鞘局灶性病变中对比增强的灵敏度。方法 对复发缓解型MS患者样本，由两名神经放射科医师使用1.5特斯拉扫描仪分别进行前瞻性检查。结局参数聚焦于急性脱髓鞘所致的钆增强检测。所有检出至少1处钆增强病变的MR检查均判定为阳性（MR+），并根据病变大小及对比度比对每处病变进行分析。结果 共分析36例MR检查结果，MR+检测的观察者间一致性较高（k值系数＞0.8），其中钆增强病变数量的一致性极佳：T1自旋回波（spin-echo, SE）序列为0.91，T1磁化传递对比（magnetization transfer contrast, MTC）序列为0.88，磁化准备快速梯度回波（magnetization-prepared rapid acquisition with gradient-echo, MPRAGE）序列为0.99。T1 MTC扫描检出的MR+病例数显著多于T1 SE序列，其次为MPRAGE扫描。可以确定，T1 MTC序列在钆增强病变检测中表现出更高的准确度，紧随其后的是T1 SE序列与MPRAGE序列。进一步对比显示，与SE及MPRAGE图像相比，T1 MTC图像的钆增强对比度比与病变面积均存在统计学意义上的显著提升。结论 在本研究纳入的MS患者样本中，单次注射钆的T1 MTC序列经1.5特斯拉磁共振扫描，被证实为检测炎症活动性病变灵敏度最高的采集序列。