Abstract：
OBJECTIVE: This study aimed to develop novel non-contrast MR perfusion techniques for assessing micro-vascularity of the foot in human subjects.
METHODS: All experiments were performed on a clinical 3 T scanner using arterial spin labeling (ASL). Seven healthy subjects (30-72 years old, 5 males and 2 females) were enrolled and bilateral feet were imaged with tag-on and tag-off alternating inversion recovery spin labeling for determining micro-vascularity. We compared an ASL technique with 1-tag against 4-tag pulses. For perfusion, we determined signal increase ratio (SIR) at varying inversion times (TI) from 0.5 to 2 s. SIR versus TI data were fit to determine perfusion metrics of peak height (PH), time to peak (TTP), full width at half maximum (FWHM), area under the curve (AUC), and apparent blood flow (aBF) in the distal foot and individual toes. Using analysis of variance (ANOVA), effects of tag pulse and region of interest (ROI) on the mean perfusion metrics were assessed. In addition, a 4-tag pulse perfusion experiment was performed on patients with peripheral artery disease (PAD) and Raynaud\'s disease.
RESULTS: Using our MR perfusion techniques, SIR versus TI data showed well-defined leading and trailing edges, with a peak near TI of 0.75-1.0 s and subsiding quickly to near zero by TI of 2 s, particularly when 4-tag pulses were used. When imaged with 4-tag pulse, we found significantly greater values in perfusion metrics, as compared to 1-tag pulse. The patients with PAD and Raynaud\'s disease showed a reduced or scattered perfusion curves compared to the healthy control.
CONCLUSIONS: MR perfusion imaging of the distal foot shows greater SIR and perfusion metrics with the 4-tag pulse compared to the 1-tag pulse technique. This will likely benefit those with low perfusion due to aging, PAD, diabetic foot, and other vascular diseases.
METHODS: All experiments were performed on a clinical 3 T scanner using arterial spin labeling (ASL). Seven healthy subjects (30-72 years old, 5 males and 2 females) were enrolled and bilateral feet were imaged with tag-on and tag-off alternating inversion recovery spin labeling for determining micro-vascularity. We compared an ASL technique with 1-tag against 4-tag pulses. For perfusion, we determined signal increase ratio (SIR) at varying inversion times (TI) from 0.5 to 2 s. SIR versus TI data were fit to determine perfusion metrics of peak height (PH), time to peak (TTP), full width at half maximum (FWHM), area under the curve (AUC), and apparent blood flow (aBF) in the distal foot and individual toes. Using analysis of variance (ANOVA), effects of tag pulse and region of interest (ROI) on the mean perfusion metrics were assessed. In addition, a 4-tag pulse perfusion experiment was performed on patients with peripheral artery disease (PAD) and Raynaud\'s disease.
RESULTS: Using our MR perfusion techniques, SIR versus TI data showed well-defined leading and trailing edges, with a peak near TI of 0.75-1.0 s and subsiding quickly to near zero by TI of 2 s, particularly when 4-tag pulses were used. When imaged with 4-tag pulse, we found significantly greater values in perfusion metrics, as compared to 1-tag pulse. The patients with PAD and Raynaud\'s disease showed a reduced or scattered perfusion curves compared to the healthy control.
CONCLUSIONS: MR perfusion imaging of the distal foot shows greater SIR and perfusion metrics with the 4-tag pulse compared to the 1-tag pulse technique. This will likely benefit those with low perfusion due to aging, PAD, diabetic foot, and other vascular diseases.
摘要：
目的：本研究旨在开发新的非对比MR灌注技术，用于评估人类受试者足部的微血管分布。
方法：所有实验均在临床3T扫描仪上使用动脉自旋标记（ASL）进行。七个健康受试者（30-72岁，招募5名男性和2名女性），并使用标签开和标签关交替反转恢复自旋标记对双侧脚进行成像，以确定微血管分布。我们将具有1标签的ASL技术与4标签脉冲进行了比较。对于灌注，我们确定信号增加比（SIR）在不同的反转时间（TI）从0.5到2s。SIR与TI数据进行拟合，以确定峰值高度（PH）的灌注指标，达到峰值的时间(TTP)半峰全宽(FWHM),曲线下面积（AUC），和远端脚和单个脚趾的表观血流量（aBF）。使用方差分析(ANOVA)，评估了标记脉冲和感兴趣区域（ROI）对平均灌注指标的影响。此外,我们对患有外周动脉疾病(PAD)和雷诺氏病的患者进行了4标记脉冲灌注实验.
结果：使用我们的MR灌注技术，SIR与TI数据显示明确的前缘和后缘，TI附近的峰值为0.75-1.0s，并通过2s的TI迅速下降到接近零，特别是当使用4标签脉冲时。当用4标签脉冲成像时，我们发现灌注指标的值明显更大，与1标签脉冲相比。与健康对照相比，患有PAD和雷诺病的患者显示出减少或分散的灌注曲线。
结论：远端足的MR灌注成像显示，与1标签脉冲技术相比，4标签脉冲的SIR和灌注指标更大。这将可能有利于那些低灌注由于老化，PAD,糖尿病足,和其他血管疾病。
方法：所有实验均在临床3T扫描仪上使用动脉自旋标记（ASL）进行。七个健康受试者（30-72岁，招募5名男性和2名女性），并使用标签开和标签关交替反转恢复自旋标记对双侧脚进行成像，以确定微血管分布。我们将具有1标签的ASL技术与4标签脉冲进行了比较。对于灌注，我们确定信号增加比（SIR）在不同的反转时间（TI）从0.5到2s。SIR与TI数据进行拟合，以确定峰值高度（PH）的灌注指标，达到峰值的时间(TTP)半峰全宽(FWHM),曲线下面积（AUC），和远端脚和单个脚趾的表观血流量（aBF）。使用方差分析(ANOVA)，评估了标记脉冲和感兴趣区域（ROI）对平均灌注指标的影响。此外,我们对患有外周动脉疾病(PAD)和雷诺氏病的患者进行了4标记脉冲灌注实验.
结果：使用我们的MR灌注技术，SIR与TI数据显示明确的前缘和后缘，TI附近的峰值为0.75-1.0s，并通过2s的TI迅速下降到接近零，特别是当使用4标签脉冲时。当用4标签脉冲成像时，我们发现灌注指标的值明显更大，与1标签脉冲相比。与健康对照相比，患有PAD和雷诺病的患者显示出减少或分散的灌注曲线。
结论：远端足的MR灌注成像显示，与1标签脉冲技术相比，4标签脉冲的SIR和灌注指标更大。这将可能有利于那些低灌注由于老化，PAD,糖尿病足,和其他血管疾病。
