BACKGROUND:Biliary ischaemia is an important factor in the pathogenesis of non-anastomotic biliary stricture (NAS) after liver transplantation (LT). Contrast-enhanced ultrasound (CEUS) can be used to detect biliary ischaemia, but no study has examined the utility of CEUS in predicting NAS. OBJECTIVE:To evaluate whether repeated CEUS as a non-invasive method of biliary ischaemia can identify NAS. METHODS:Consecutive LT patients who underwent CEUS examinations at 1–4 weeks after LT from September 2012 to December 2015 at our institution were included. The CEUS images and clinical data were analysed. RESULTS:Among 116 eligible LT patients, 39 (33.6%) were diagnosed with NAS within 1 year after LT. The patients with NAS had a significantly higher CEUS score at weeks 2–4 (all P < 0.05) and a higher slope of CEUS score progression (0.480 vs –0.044, P < 0.001). The accuracy of CEUS in identifying NAS improved over time after LT, reaching its maximum at week 4, with a sensitivity of 66.7%, a specificity of 87.9%, a positive predictive value (PPV) of 75.9%, a negative predictive value (NPV) of 82.3%, and an accuracy of 80.2%in the full cohort when a CEUS score≥3 was used as the cut-off. Multivariate analysis identified gamma-glutamyl transpeptidase (GGT), alanine transaminase (ALT) and the CEUS score at week 4 as independent predictors of NAS. In the task of identifying NAS, an NAS score combining the above 3 variables at week 4 showed areas under the receiver operating characteristic curve of 0.88 (95%CI, 0.78–0.99) in the estimation group (n = 60) and 0.82 (95%CI, 0.69–0.96) in the validation group (n = 56). An NAS score cut-off of 0.396 identified 87.2%of NAS cases in the estimation group, with a PPV of 93.3%; and 75.0%of NAS cases in the validation group, with a PPV of 58.8%. CONCLUSIONS:CEUS examination during the first 4 weeks is useful in assessing the risk of NAS within 1 year after LT. In particular, an NAS score combining the CEUS score, GGT level, and ALT level at week 4 can be used to accurately predict the risk of NAS in LT patients.

中文翻译：

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肝移植后前 4 周内胆道缺血的 CEUS 检测可预测非吻合性胆道狭窄

背景：胆道缺血是肝移植（LT）后非吻合性胆道狭窄（NAS）发病的重要因素。对比增强超声 (CEUS) 可用于检测胆道缺血，但没有研究检查 CEUS 在预测 NAS 中的效用。目的：评估重复超声造影作为胆道缺血的一种非侵入性方法能否鉴别NAS。方法：2012 年 9 月至 2015 年 12 月在我们机构接受 LT 后 1-4 周的连续 LT 患者。分析了 CEUS 图像和临床数据。结果：在 116 名符合条件的 LT 患者中，39 名（33.6%）在 LT 后 1 年内被诊断出患有 NAS。NAS 患者在第 2-4 周具有显着更高的 CEUS 评分（所有 P < 0.05）和更高的 CEUS 评分进展斜率（0.480 vs –0.044，P < 0.001)。CEUS 识别 NAS 的准确率在 LT 后随时间提高，在第 4 周达到最大值，敏感性为 66.7%，特异性为 87.9%，阳性预测值（PPV）为 75.9%，阴性预测值（NPV） ) 的 82.3%，当 CEUS 评分≥3 作为截止值时，整个队列的准确率为 80.2%。多变量分析将第 4 周的 γ-谷氨酰转肽酶 (GGT)、丙氨酸转氨酶 (ALT) 和 CEUS 评分确定为 NAS 的独立预测因子。在识别 NAS 的任务中，第 4 周结合上述 3 个变量的 NAS 评分显示，估计组（n = 60）和 0.82（95 %CI, 0.69–0.96) 在验证组 (n = 56)。NAS 分数截止值为 0.396，确定为 87。估计组 2% 的 NAS 病例，PPV 为 93.3%；验证组中 75.0% 的 NAS 病例，PPV 为 58.8%。结论：前 4 周的 CEUS 检查有助于评估 LT 后 1 年内发生 NAS 的风险。特别是，结合第 4 周 CEUS 评分、GGT 水平和 ALT 水平的 NAS 评分可用于准确预测 LT 患者发生 NAS 的风险。