胰泌素增强扩散加权成像诊断轻度慢性胰腺炎的价值

Assessment of mild chronic pancreatitis：the utility of diffusion weighted imaging before and after secretin stimulation

目的：探讨胰泌素增强DWI（S-DWI）诊断轻度慢性胰腺炎（CP）的价值。方法前瞻性收集临床诊断的CP患者65例、健康志愿者23名、风险志愿者11例，CP患者依据内镜下逆行胰胆管造影、CT、超声内镜结果，分为轻度CP组15例、中度CP组14例、重度CP组36例。99例受试者均行S-DWI检查，测量计算各组受试者注射胰泌素前ADC值，注射胰泌素后ADC峰值、达峰时间、注射胰泌素前后ADC值增加百分比，并测定粪便内弹力蛋白酶1（FE-1）含量。采用单因素方差分析比较健康志愿者、风险志愿者、CP（轻度、中度和重度CP）组间DWI测量指标和FE-1值的差异，采用Pearson检验评价DWI测量指标和FE-1值的相关性，采用ROC分析DWI测量指标诊断轻度CP的效能。结果8例重度CP患者由于胰腺实质明显萎缩，无法测量其ADC值被剔除，91例受试者分为5组，分别为健康志愿者组23名、风险志愿者组11例、轻度CP组15例、中度CP组14例、重度CP组28例。健康志愿者组注射胰泌素前ADC值、注射后ADC峰值均高于其他各组，达峰时间低于其他组，差异均有统计学意义（P均〈0.05）。重度CP组未出现ADC峰值，其余各组注射前、后ADC值差异均有统计学意义（P均〈0.05）；轻度CP组和中度CP组达峰时间均有延迟。注射前ADC值、注射后ADC峰值和达峰时间诊断轻度CP的ROC下面积分别为0.818、0.912和0.965。以4.67 min为达峰时间阈值，诊断轻度CP的敏感度和特异度分别为80.0%和100.0%。注射前ADC值、注射后ADC峰值、达峰时间与FE-1间具有相关性（r值分别为0.57、0.72和－0.84，P均〈0.01）。结论注射胰泌素后ADC峰值和达峰时间可以诊断轻度CP，S-DWI是一项无创、便捷、准确的诊断轻度CP的方法。

Objective To explore the diagnostic value of DWI after secretin stimulation for the diagnosis of mild chronic pancreatitis （CP）. Methods This was a prospective study. Ninety-nine consecutive individuals including 23 healthy volunteers, 11 risk volunteers, 15 mild CP patients, 14 moderate CP patients and 36 severe CP patients underwent secretin DWI and faecal elastase 1（FE-1） testing. The subjects were grouped by Cambridge classification about endoscopic retrograde cholangiography （ERCP）, CT and ultrasonography. Secretin stimulated diffusion weighted imaging（S-DWI）, the ADCs, time to peak ADCs and FE-1 were performed on all subjects. The changes of pancreatic ADC values were observed before and after the injection of secretin. All ADCs and FE-1 were compared between groups with single factor analysis of variance, and the correlation between ADCs and FE-1 was determined with Pearson analysis. ROC curves were performed to identify the diagnostic efficacy of DWI related measures. Results Eight patients with severe CP were excluded because the significant atrophy of the pancreatic parenchyma prohibited the evaluation of ADC measurement. Ninety-one individuals were divided into five groups including 23 healthy volunteers, 11 risk volunteers, 15 mild CP patients, 14 moderate CP patients and 28＆amp;nbsp;severe CP patients. The mean baseline and peak ADCs were higher in the healthy volunteers than in other groups, with significant differences （P〈0.05）. There was no ADC peak in severe CP patients. There were significant differences between the mean baseline ADCs and the peak ADCs in the other groups （P〈0.05）. The mild and moderate CP groups showed a delayed peak. The area under curve （AUC） of the mean baseline and peak ADCs, time to peak ADCs for differentiating mild CP was 0.818, 0.912 and 0.965, respectively. Using 4.67 min as the cutoff value, time to peak ADCs were most accurate for differentiating healthy from risk patients and those with evident pancreatitis, yielding a sensitivity of 80.0%and a specificity of 100.0%. Good correlations between baseline and peak ADCs, time to peak ADCs, and FE-1 were shown（r=0.57, 0.72 and-0.84, P〈0.01）. Conclusions Using the peak and time to peak ADCs may improve the detection of risk and mild CP. Secretin-enhanced DWI is a noninvasive, convenient and accurate method.