From the Department of Neurology (A.H., W.W.), Heidelberg University Hospital, Heidelberg, Germany.
Department of Diagnostic and Interventional Radiology (K.Z.), Heidelberg University Hospital, Heidelberg, Germany.
AJNR Am J Neuroradiol. 2024 Sep 9;45(9):1346-1354. doi: 10.3174/ajnr.A8344.
The novel MR imaging technique of vascular architecture mapping allows in vivo characterization of local changes in cerebral microvasculature, but reference ranges for vascular architecture mapping parameters in healthy brain tissue are lacking, limiting its potential applicability as an MR imaging biomarker in clinical practice. We conducted whole-brain vascular architecture mapping in a large cohort to establish vascular architecture mapping parameter references ranges and identify region-specific cortical and subcortical microvascular profiles.
This was a single-center examination of adult patients with unifocal, stable low-grade gliomas with multiband spin- and gradient-echo EPI sequence at 3T using parallel imaging. Voxelwise plotting of resulting values for gradient-echo (R*) versus spin-echo (R) relaxation rates during contrast agent bolus administration generates vessel vortex curves that allow the extraction of vascular architecture mapping parameters representative of, eg, vessel type, vessel radius, or CBV in the underlying voxel. Averaged whole-brain parametric maps were calculated for 9 parameters, and VOI analysis was conducted on the basis of a standardized brain atlas and individual cortical GM and WM segmentation.
Prevalence of vascular risk factors among subjects ( = 106; mean age, 39.2 [SD, 12.5] years; 56 women) was similar to those in the German population. Compared with WM, we found cortical GM to have larger mean vascular calibers (5.80 [SD, 0.59] versus 4.25 [SD, 0.62] < .001), increased blood volume fraction (20.40 [SD, 4.49] s versus 11.05 [SD, 2.44] s; < .001), and a dominance of venous vessels. Distinct microvascular profiles emerged for cortical GM, where vascular architecture mapping vessel type indicator differed, eg, between the thalamus and cortical GM (mean, -2.47 [SD, 4.02] s versus -5.41 [SD, 2.84] s; < .001). Intraclass correlation coefficient values indicated overall high test-retest reliability for vascular architecture mapping parameter mean values when comparing multiple scans per subject.
Whole-brain vascular architecture mapping in the adult brain reveals region-specific microvascular profiles. The obtained parameter reference ranges for distinct anatomic and functional brain areas may be used for future vascular architecture mapping studies on cerebrovascular pathologies and might facilitate early discovery of microvascular changes, in, eg, neurodegeneration and neuro-oncology.
新型 MR 血管结构成像技术可在体对脑微血管的局部变化进行特征描述，但健康脑组织的血管结构成像参数参考范围仍缺乏，限制了其作为一种临床实践中的 MR 成像生物标志物的潜在适用性。本研究在一个大样本中进行全脑血管结构成像，以建立血管结构成像参数参考范围，并确定特定于区域的皮质和皮质下微血管特征。
这是一项在 3T 磁共振扫描仪上使用多带自旋和梯度回波 EPI 序列对单灶性、稳定的低级别脑胶质瘤患者进行的单中心检查。在对比剂团注过程中，梯度回波（R*）与自旋回波（R）弛豫率之间的关系呈涡流曲线，可提取出代表像素下血管类型、血管半径或 CBV 等血管结构成像参数。对 9 个参数进行全脑平均参数图计算，并基于标准化脑图谱和个体皮质 GM 和 WM 分割进行 VOI 分析。
受试者（ = 106；平均年龄 39.2 [标准差 12.5]岁；56 名女性）的血管危险因素患病率与德国人群相似。与 WM 相比，我们发现皮质 GM 的平均血管口径较大（5.80 [标准差 0.59] 与 4.25 [标准差 0.62]；< .001），血容量分数较高（20.40 [标准差 4.49] s 与 11.05 [标准差 2.44] s；< .001），且静脉血管占主导地位。皮质 GM 存在不同的微血管特征，例如丘脑和皮质 GM 的血管结构成像血管类型指标不同（平均，-2.47 [标准差 4.02] s 与-5.41 [标准差 2.84] s；< .001）。对每位受试者的多次扫描进行比较时，血管结构成像参数平均值的组内相关系数值表明整体具有较高的测试-重测可靠性。
成人脑的全脑血管结构成像揭示了特定区域的微血管特征。不同解剖和功能脑区获得的参数参考范围可用于未来的脑血管病和神经退行性疾病的血管结构成像研究，并可能有助于早期发现微血管变化，如神经退行性疾病和神经肿瘤学。
