基于原卟啉 IX 荧光的高光谱成象术检测脑胶质瘤的改进-视觉识别与机器阈值的体外比较
Detection improvement of gliomas in hyperspectral imaging of protoporphyrin IX fluorescence - in vitro comparison of visual identification and machine thresholds.
机构信息
Neurosurgery Clinical Research Unit, Institute of Clinical Sciences, School of Medicine, Faculty of Health Sciences, UEF University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland; Microneurosurgery Photonics Research Group of The Microsurgery Center of Eastern Finland, Neurosurgery of Neurocenter, KUH Kuopio University Hospital, Puijonlaaksontie 2, 70210 Kuopio, Finland.
Microneurosurgery Photonics Research Group of The Microsurgery Center of Eastern Finland, Neurosurgery of Neurocenter, KUH Kuopio University Hospital, Puijonlaaksontie 2, 70210 Kuopio, Finland; School of Computing, UEF University of Eastern Finland, Länsikatu 15, 80110 Joensuu, Finland; Institute of Photonics, UEF University of Eastern Finland, Länsikatu 15, 80110 Joensuu, Finland.
出版信息
Cancer Treat Res Commun. 2022;32:100615. doi: 10.1016/j.ctarc.2022.100615. Epub 2022 Jul 20.
BACKGROUND
5-aminolevulinic acid (5-ALA) - precursor of protoporphyrin IX (PpIX) - is utilized in fluorescence guided surgery (FGS) of high-grade gliomas. PpIX is used to identify traces of glioma during resection. Visual inspection of the fluorescence seems inaccurate in comparison to optic techniques such as hyperspectral imaging (HSI).
AIM
To characterize the limits of PpIX fluorescence detection of (i) visual evaluation and (ii) HSI analysis and to (iii) develop a classification system for visible and non-visible PpIX fluorescence.
METHODS
Samples with increasing concentrations (C) of PpIX and non-fluorescent controls were evaluated using a surgical microscope under blue light illumination. Similar samples were imaged with a HSI system tuned to PpIX fluorescence peak wavelength (635 nm) and control (RGB) channels. Samples' intensities were defined, leading to 96 analysed pixels after batching.
RESULTS
Three expert neurosurgeons assessed the PpIX samples (n = 16) and controls (n = 8) with unanimous decisions (ICC = 0.704), resulting in 63% recognition rate, 48% sensitivity, 92% specificity, 92% positive predictive value (PPV) and 47% negative predictive value (NPV). HSI image analysis, comparing mean relative values, resulted in 96%, 100%, 86%, 94%, 100%, respectively. Minimum PpIX concentration detection for experts was 0.6-1.8 μmol/l and HSI's 0.03-0.15 μmol/l.
CONCLUSIONS
PpIX concentrations of low-grade gliomas, and those reported on glioblastoma infiltration zones, are below experts' detection threshold. HSI analysis exceeds the performance of expert's visual inspection nearly by 20-fold. Hybrid FGS-HSI systems should be investigated in parallel to long-term outcomes. Described methods are applicable as a standard for calibration, testing and development of subvisual FGS techniques.
背景
5-氨基酮戊酸（5-ALA）是原卟啉 IX（PpIX）的前体，用于高级别脑胶质瘤的荧光引导手术（FGS）。PpIX 用于在切除过程中识别胶质瘤的痕迹。与高光谱成像（HSI）等光学技术相比，荧光的目视检查似乎不够准确。
目的
描述（i）视觉评估和（ii）HSI 分析中 PpIX 荧光检测的局限性，并（iii）为可见和不可见 PpIX 荧光开发分类系统。
方法
使用手术显微镜在蓝光照射下评估 PpIX 浓度（C）逐渐增加的样本和非荧光对照样本。使用调谐至 PpIX 荧光峰值波长（635nm）和对照（RGB）通道的 HSI 系统对类似样本进行成像。对样本的强度进行定义，批量处理后得到 96 个分析像素。
结果
三位神经外科专家评估了 PpIX 样本（n=16）和对照样本（n=8），并做出一致的决策（ICC=0.704），识别率为 63%，敏感性为 48%，特异性为 92%，阳性预测值（PPV）为 92%，阴性预测值（NPV）为 47%。HSI 图像分析，比较平均相对值，结果分别为 96%、100%、86%、94%、100%。专家检测到的最低 PpIX 浓度为 0.6-1.8μmol/L，HSI 为 0.03-0.15μmol/L。
结论
低级别脑胶质瘤和报道的脑胶质母细胞瘤浸润区的 PpIX 浓度低于专家的检测阈值。HSI 分析的性能几乎超过专家目视检查的 20 倍。应研究杂交 FGS-HSI 系统以获得长期结果。所描述的方法可作为亚视觉 FGS 技术的校准、测试和开发的标准。
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