BOLD signal within and around white matter lesions distinguishes multiple sclerosis and non-specific white matter disease: a three-dimensional approach

Multiple sclerosis (MS) diagnostic criteria are based upon clinical presentation and presence of white matter hyperintensities on two-dimensional magnetic resonance imaging (MRI) views. Such criteria, however, are prone to false-positive interpretations due to the presence of similar MRI findings in non-specific white matter disease (NSWMD) states such as migraine and microvascular disease. The coexistence of age-related changes has also been recognized in MS patients, and this comorbidity further poses a diagnostic challenge. In this study, we investigated the physiologic profiles within and around MS and NSWMD lesions and their ability to distinguish the two disease states. MS and NSWMD lesions were identified using three-dimensional (3D) T 2 -FLAIR images and segmented using geodesic active contouring. A dual-echo functional MRI sequence permitted near-simultaneous measurement of blood-oxygen-level-dependent signal (BOLD) and cerebral blood flow (CBF). BOLD and CBF were calculated within lesions and in 3D concentric layers surrounding each lesion. BOLD slope, an indicator of lesion metabolic capacity, was calculated as the change in BOLD from a lesion through its surrounding perimeters. We observed sequential BOLD signal reductions from the lesion towards the perimeters for MS, while no such decreases were observed for NSWMD lesions. BOLD slope was significantly lower in MS compared to NSWM lesions, suggesting decreased metabolic activity in MS lesions. Furthermore, BOLD signal within and around lesions significantly distinguished MS and NSWMD lesions. These results suggest that this technique shows promise for clinical utility in distinguishing NSWMD or MS disease states and identifying NSWMD lesions occurring in MS patients.

多发性硬化（MS）的诊断标准基于临床表现以及二维磁共振成像（MRI）图像上白质高信号的存在。然而，由于在非特异性白质疾病（NSWMD）状态（如偏头痛和微血管疾病）中存在类似的MRI表现，此类标准容易出现假阳性解读。在MS患者中也已认识到与年龄相关变化的共存，这种共病进一步带来了诊断挑战。在本研究中，我们研究了MS和NSWMD病变内部及周围的生理特征以及它们区分这两种疾病状态的能力。使用三维（3D）T₂ -FLAIR图像识别MS和NSWMD病变，并使用测地线活动轮廓法进行分割。双回波功能磁共振成像序列允许近乎同时测量血氧水平依赖信号（BOLD）和脑血流量（CBF）。在病变内以及围绕每个病变的3D同心层中计算BOLD和CBF。BOLD斜率是病变代谢能力的一个指标，计算为从病变到其周围边界的BOLD变化。我们观察到MS从病变到边界的BOLD信号依次降低，而NSWMD病变未观察到此类降低。与NSWM病变相比，MS中的BOLD斜率显著更低，表明MS病变中的代谢活动降低。此外，病变内部及周围的BOLD信号显著区分了MS和NSWMD病变。这些结果表明，该技术在区分NSWMD或MS疾病状态以及识别MS患者中出现的NSWMD病变方面具有临床应用前景。