Netteland Dag Ferner, Aarhus Mads, Smistad Erik, Sandset Else Charlotte, Padayachy Llewellyn, Helseth Eirik, Brekken Reidar
Department of Neurosurgery, Oslo University Hospital Ullevål, Oslo, Norway.
Faculty of Medicine, University of Oslo, Oslo, Norway.
Front Neurol. 2023 Feb 1;14:1064492. doi: 10.3389/fneur.2023.1064492. eCollection 2023.
Optic nerve sheath diameter (ONSD) has shown promise as a noninvasive parameter for estimating intracranial pressure (ICP). In this study, we evaluated a novel automated method of measuring the ONSD in transorbital ultrasound imaging.
From adult traumatic brain injury (TBI) patients with invasive ICP monitoring, bedside manual ONSD measurements and ultrasound videos of the optic nerve sheath complex were simultaneously acquired. Automatic ONSD measurements were obtained by the processing of the ultrasound videos by a novel software based on a machine learning approach for segmentation of the optic nerve sheath. Agreement between manual and automated measurements, as well as their correlation to invasive ICP, was evaluated. Furthermore, the ability to distinguish dichotomized ICP for manual and automatic measurements of ONSD was compared, both for ICP dichotomized at ≥20 mmHg and at the 50th percentile (≥14 mmHg). Finally, we performed an exploratory subgroup analysis based on the software's judgment of optic nerve axis alignment to elucidate the reasons for variation in the agreement between automatic and manual measurements.
A total of 43 ultrasound examinations were performed on 25 adult patients with TBI, resulting in 86 image sequences covering the right and left eyes. The median pairwise difference between automatically and manually measured ONSD was 0.06 mm (IQR -0.44 to 0.38 mm; = 0.80). The manually measured ONSD showed a positive correlation with ICP, while automatically measured ONSD showed a trend toward, but not a statistically significant correlation with ICP. When examining the ability to distinguish dichotomized ICP, manual and automatic measurements performed with similar accuracy both for an ICP cutoff at 20 mmHg (manual: AUC 0.74, 95% CI 0.58-0.88; automatic: AUC 0.83, 95% CI 0.66-0.93) and for an ICP cutoff at 14 mmHg (manual: AUC 0.70, 95% CI 0.52-0.85; automatic: AUC 0.68, 95% CI 0.48-0.83). In the exploratory subgroup analysis, we found that the agreement between measurements was higher in the subgroup where the automatic software evaluated the optic nerve axis alignment as good as compared to intermediate/poor.
The novel automated method of measuring the ONSD on the ultrasound videos using segmentation of the optic nerve sheath showed a reasonable agreement with manual measurements and performed equally well in distinguishing high and low ICP.
视神经鞘直径（ONSD）已显示出作为估计颅内压（ICP）的无创参数的前景。在本研究中，我们评估了一种在经眶超声成像中测量ONSD的新型自动化方法。
从接受有创ICP监测的成年创伤性脑损伤（TBI）患者中，同时获取床边手动ONSD测量值和视神经鞘复合体的超声视频。通过基于机器学习方法对视神经鞘进行分割的新型软件处理超声视频，获得自动ONSD测量值。评估手动测量与自动测量之间的一致性，以及它们与有创ICP的相关性。此外，比较了手动和自动测量ONSD区分二分法ICP的能力，ICP二分法分别为≥20 mmHg和第50百分位数（≥14 mmHg）。最后，我们基于软件对视神经轴对齐的判断进行了探索性亚组分析，以阐明自动测量与手动测量之间一致性差异的原因。
对25例成年TBI患者共进行了43次超声检查，产生了86个覆盖右眼和左眼的图像序列。自动测量与手动测量的ONSD之间的中位成对差异为0.06 mm（IQR -0.44至0.38 mm； = 0.80）。手动测量的ONSD与ICP呈正相关，而自动测量的ONSD与ICP呈趋势性相关，但无统计学显著相关性。在检查区分二分法ICP的能力时，对于ICP截断值为20 mmHg（手动：AUC 0.74，95% CI 0.58 - 0.88；自动：AUC 0.83，95% CI 0.66 - 0.93）和ICP截断值为14 mmHg（手动：AUC 0.70，95% CI 0.52 - 0.85；自动：AUC 0.68，95% CI 0.48 - 0.83），手动和自动测量的准确性相似。在探索性亚组分析中，我们发现与中等/差相比，自动软件评估视神经轴对齐良好的亚组中测量之间的一致性更高。
使用视神经鞘分割在超声视频上测量ONSD的新型自动化方法与手动测量显示出合理的一致性，并且在区分高ICP和低ICP方面表现同样良好。
