Gadolinium Retention Estimation Tool

This Excel file provides a tool for estimating gadolinium (Gd) retention in patients based on the time (in months) between MRI gadolinium contrast media (Gd-CM) administration and urine sample collection. Users can input spot urine and Chelate-Evoked Metal Excretion Test (CEMET) urine Gd concentrations in µg/g creatinine along the time lapse after Gd-CM exposure in months. The results are then plotted into norm-regression curves with ±95% confidence intervals (CI) to provide an estimate of the lag-time-specific Gd retention.The regression curves are based on data from 54 patient samples. Spot urine samples were collected in the morning while fasting. Subsequently, a standard intravenous infusion of 600 mg glutathione, 1.9 g Na-Ca-EDTA, and 250 mg DMPS was administered, with CEMET urine collected two hours after infusion initiation. This combination of chelation agents enhances sensitivity and broadens the range of metals captured by CEMET.Na-Ca-EDTA effectively binds and promotes the urinary excretion of gadolinium, making it a viable alternative to Zn-DTPA. The tool generates two distinct regression curves: one for short- to medium-term gadolinium retention (<24 months, in sheet 1) and another for long-term retention (2–10 years, in sheet 2), reflecting different slope trends over time.Sheet 3 includes a Python script that enables users to generate norm diagrams and aggregate patient data. This script can be customized to adjust norm diagrams and 95% CIs for specific research questions or patient subsets, such as those differentiated by renal function, lifetime gadolinium exposure, or specific Gd-CM types or brands.While this tool estimates gadolinium retention in tissues after defined intervals following Gd-CM administration, elevated retention values do not necessarily correlate with clinical symptoms. Patients with typical retention may still exhibit symptoms, while those with elevated retention might remain asymptomatic.Increased sensitivity to gadolinium and related pathologies seems to involve autoimmune mechanisms or predisposing factors, such as decreased metal tolerance or increased pre-exam metal exposure, which are not directly linked to gadolinium concentrations in blood or urine. Therefore, this tool is valuable for estimating individual gadolinium retention after Gd-CM exposure but is not intended to determine toxicity levels.

本Excel文件提供了一款用于估算患者体内钆（Gadolinium，Gd）滞留量的工具，其计算依据为磁共振钆对比剂（Gadolinium Contrast Media，Gd-CM）给药与尿液样本采集之间的间隔时长（单位：月）。用户可输入Gd-CM给药后间隔时长（单位：月）对应的随机尿液样本及螯合激发金属排泄试验（Chelate-Evoked Metal Excretion Test，CEMET）尿液钆浓度，单位为µg/g肌酐。所得结果将被绘制成带有±95%置信区间（Confidence Intervals，CI）的标准回归曲线，以估算特定滞后时间下的钆滞留量。
该回归曲线基于54份患者样本的数据构建。随机尿液样本于晨起空腹状态下采集。随后，为患者静脉输注标准剂量的600mg谷胱甘肽、1.9g依地酸钙钠（Na-Ca-EDTA）与250mg二巯丙磺钠（Dimercaptopropanesulfonate，DMPS），于输注开始后2小时采集CEMET尿液样本。该螯合剂联用方案可提升检测灵敏度，并拓宽CEMET所能捕获的金属种类范围。
依地酸钙钠可有效结合钆并促进其经尿液排泄，是二乙三胺五乙酸锌（Zn-DTPA）的可行替代方案。该工具可生成两条独立的回归曲线：一条用于估算中短期钆滞留量（<24个月，位于工作表1），另一条用于估算长期钆滞留量（2~10年，位于工作表2），二者随时间变化的斜率趋势存在差异。
工作表3包含一段Python脚本，可帮助用户生成标准图表并汇总患者数据。该脚本支持自定义调整，可针对特定研究需求或患者亚组（如按肾功能、终身钆暴露量、特定Gd-CM类型或品牌划分的亚组）调整标准图表与95%置信区间。
尽管本工具可估算Gd-CM给药后特定间隔时间内患者体内组织的钆滞留量，但钆滞留量升高并不一定与临床症状相关。钆滞留量处于正常水平的患者仍可能出现相关症状，而钆滞留量升高的患者也可能无任何症状。
机体对钆及相关病症的易感性升高，似乎与自身免疫机制或易感因素有关，例如金属耐受性下降或检查前金属暴露量增加，此类因素与血液或尿液中的钆浓度并无直接关联。因此，本工具可用于估算Gd-CM暴露后个体的钆滞留量，但不可用于判定中毒程度。