Purpose

Together with the foramen ovale, the middle meningeal artery (MMA) looks like a high heel shoe print on axial time-of-flight magnetic resonance angiography (TOF-MRA) images, with the MMA resembling the heel. Cranial dural arteriovenous fistulas (DAVF) are often fed by the MMA, which can lead to an increase of signal intensity and diameter of this vessel, resulting in a more “shiny” and “thick” high heel print appearance than on the contralateral side. We describe this finding as a novel radiologic sign and provide cut-off values for the ratios of MMA signal intensities and diameters for predicting the presence of a DAVF.

Methods

A total of 84 TOF-MRA examinations of 44 patients with DAVFs (40 with unilateral MMA feeders, 4 with bilateral feeders) and of 40 patients without DAVFs were included. Diameters and signal intensities of both MMAs were measured by two raters and evaluated using receiver operating characteristic analysis.

Results

The diameters of feeding and non-feeding MMAs differed significantly, as did the ratios of signal intensities and of diameters of DAVF and control patients (P < 0.0001). Cut-off values were 1.25 for average signal intensity ratio (shiny high heel sign) and 1.21 for diameter ratio (thick high heel sign). The combination of the “shiny” and the “thick” high heel sign resulted in the highest sensitivity (92.5%) and positive predictive value (95%).

Conclusion

The described sign seems promising for the detection of DAVFs with noncontrast-enhanced MRI. The TOF-MRA source images should be reviewed with special attention to the MMA.

中文翻译：

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“闪亮而厚实的高跟鞋标志”

目的

与卵圆孔一起，脑膜中动脉 (MMA) 在轴向飞行时间磁共振血管造影 (TOF-MRA) 图像上看起来像高跟鞋印记，MMA 类似于脚跟。颅脑硬脑膜动静脉瘘 (DAVF) 通常由 MMA 供血，这会导致该血管的信号强度和直径增加，从而导致比对侧更“闪亮”和“厚”的高跟鞋印外观。我们将这一发现描述为一种新的放射学标志，并提供 MMA 信号强度和直径比率的截止值，以预测 DAVF 的存在。

方法

共纳入 44 例 DAVF 患者（40 例单侧 MMA 馈线，4 例双侧馈线）和 40 例无 DAVF 患者的 84 次 TOF-MRA 检查。两个 MMA 的直径和信号强度由两个评估者测量，并使用接收器操作特征分析进行评估。

结果

喂养和非喂养MMA的直径存在显着差异，DAVF和对照患者的信号强度和直径比也有显着差异（P  <0.0001）。平均信号强度比（闪亮的高跟鞋标志）的截止值为 1.25，直径比（厚高跟鞋标志）的截止值为 1.21。“闪亮”和“厚”高跟鞋标志的组合导致最高的敏感性（92.5%）和阳性预测值（95%）。

结论

所描述的迹象似乎有希望通过非对比增强 MRI 检测 DAVF。审查 TOF-MRA 源图像时应特别注意 MMA。