Purpose. To investigate image intensity histograms as a potential source of useful imaging biomarkers in both a clinical example of detecting immune-related colitis (irColitis) in ¹⁸F-FDG PET/CT images of immunotherapy patients and an idealized case of classifying digital reference objects (DRO). Methods. Retrospective analysis of bowel ¹⁸F-FDG uptake in N=40 patients receiving immune checkpoint inhibitors was conducted. A CNN trained to segment the bowel was used to generate the histogram of bowel ¹⁸F-FDG uptake, and percentiles of the histogram were considered as potential metrics for detecting inflammation associated with irColitis. A model of the colon was also considered using cylindrical DRO. Classification of DRO with different intensity distributions was undertaken under varying geometry and noise settings. Results. The most predictive biomarker of irColitis was the 95th percentile of the bowel SUV histogram (SUV_95%). Patients later diagnosed with irColitis had a significantly higher increase in SUV_95% from baseline to first on-treatment PET than patients who did not experience irColitis (p=0.02). An increase in SUV_95%> + 40% separated pre-irColitis change from normal variability with a sensitivity of 75% and specificity of 88%. Furthermore, histogram percentiles were ideal metrics for classifying ‘hot center’ and ‘cold center’ DRO, and were robust to varying DRO geometry and noise, and to the presence of spoiler volumes unrelated to the detection task. Conclusions. The 95th percentile of the bowel SUV histogram was the optimal metric for detecting irColitis on ¹⁸F-FDG PET/CT. Image intensity histograms are a promising source of imaging biomarkers for clinical tasks.

目的。^{在免疫治疗患者的18 个}F-FDG PET/CT 图像中检测免疫相关结肠炎 (irColitis) 的临床示例和数字参考对象分类的理想案例 (DRO ) 中，研究图像强度直方图作为有用的成像生物标志物的潜在来源）。方法。^{对接受免疫检查点抑制剂的 N = 40 名患者的肠18} F-FDG 摄取进行了回顾性分析。受过训练以分割肠道的 CNN 被用于生成肠道^{18的直方图}F-FDG 摄取和直方图的百分位数被认为是检测与 irColitis 相关的炎症的潜在指标。还考虑使用圆柱形 DRO 建立结肠模型。在不同的几何形状和噪声设置下对具有不同强度分布的 DRO 进行分类。结果。irColitis 最具预测性的生物标志物是肠道 SUV 直方图的第 95 个百分位（SUV _95%）。与未经历 irColitis 的患者相比，后来被诊断患有 irColitis 的患者的 SUV从基线到首次治疗 PET增加_{95%显着更高（p=0.02）。}SUV增加_95%> + 40% 从正常变异中分离出结肠炎前的变化，敏感性为 75%，特异性为 88%。此外，直方图百分位数是分类“热中心”和“冷中心”DRO 的理想指标，并且对变化的 DRO 几何形状和噪声以及与检测任务无关的扰流器体积的存在具有鲁棒性。结论。^{肠道 SUV 直方图的第 95 个百分位是在18} F-FDG PET/CT上检测 irColitis 的最佳指标。图像强度直方图是用于临床任务的成像生物标志物的有前途的来源。