Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
J Endourol. 2013 Aug;27(8):1037-40. doi: 10.1089/end.2012.0683. Epub 2013 Jul 5.
Digital Light Processing hyperspectral imaging (HsI) produces a highly sensitive, real-time tissue oxygenation map to monitor renal perfusion/oxygenation during partial nephrectomy (PN). Our initial experience with HsI revealed considerable variation in the baseline renal oxygenation, and we sought to correlate these differences with postoperative renal function.
Hyperspectral images were collected intraoperatively in patients undergoing PN for cortical tumors. The kidney was illuminated with visible light (520-645 nm), the spectrum corresponding to that of oxyhemoglobin. Reflectance images were captured and digitally processed to determine the percentage of oxyhemoglobin (HbO2) at each image pixel. Images were taken before hilar occlusion; these %HbO2 values were used to categorize patients as high (>75% HbO2) or low (<75% HbO2) oxygenation, and postoperative eGFR was assessed.
There were 26 patients who underwent PN with ice cooling and HsI imaging. Nineteen patients had a "low" preclamp oxygenation (mean 69%) while the other 7 had a "high" HbO2 (mean 77%). There was no difference in tumor size, hematocrit value, clamp time, or preoperative eGFR between the two groups. Patients with a higher baseline %HbO2 had no significant postoperative change in their eGFR (mean 0 mL/min/1.73 m(2), +4%), while those with the lower baseline %HbO2 had a significant acute decline (mean 15 mL/min/1.73 m(2), -20%, P=0.02, 0.006).
Baseline renal oxygenation, as measured with HsI, may help predict risk of postoperative renal insufficiency and may distinguish between patients with otherwise similar baseline characteristics, such as eGFR. HsI may provide individualized assessment of renal function to influence intraoperative decision-making to help preserve renal function.
数字光处理高光谱成像（HsI）可生成高度敏感的实时组织氧合图，以监测部分肾切除术（PN）期间的肾脏灌注/氧合。我们在 HsI 方面的初步经验显示，基线肾脏氧合存在相当大的差异，我们试图将这些差异与术后肾功能相关联。
对因皮质肿瘤而行 PN 的患者术中采集高光谱图像。肾脏用可见光（520-645nm）照射，光谱对应于氧合血红蛋白。捕获反射图像并进行数字处理，以确定每个图像像素的氧合血红蛋白（HbO2）百分比。在肾门阻断前进行图像采集；使用这些%HbO2 值对患者进行分类，分为高（>75%HbO2）或低（<75%HbO2）氧合，并评估术后 eGFR。
共有 26 例接受冰冷却和 HsI 成像的患者行 PN。19 例患者在夹闭前有“低”氧合（平均 69%），而另外 7 例患者有“高”HbO2（平均 77%）。两组之间的肿瘤大小、血细胞比容值、夹闭时间或术前 eGFR 无差异。基线%HbO2 较高的患者术后 eGFR 无显著变化（平均 0mL/min/1.73m2，+4%），而基线%HbO2 较低的患者则明显下降（平均 15mL/min/1.73m2，-20%，P=0.02，0.006）。
用 HsI 测量的基线肾脏氧合可能有助于预测术后肾功能不全的风险，并可能区分其他基线特征相似的患者，如 eGFR。HsI 可提供对肾功能的个体化评估，从而影响术中决策，有助于保护肾功能。
