Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, 600 N Wolfe St, Room 143, Baltimore, MD, 21287, USA.
Department of Pathology, Johns Hopkins Medical Institutions, 1550 Orleans Street, Baltimore, MD, 21231, USA.
Eur Radiol. 2018 Apr;28(4):1560-1567. doi: 10.1007/s00330-017-5122-3. Epub 2017 Nov 13.
To evaluate and compare the accuracy of absolute apparent diffusion coefficient (ADC) and normalised ADC (lesion-to-spleen ADC ratio) in differentiating pancreatic neuroendocrine tumour (NET) from intrapancreatic accessory spleen (IPAS).
Study included 62 patients with the diagnosis of pancreatic NET (n=51) or IPAS (n=11). Two independent reviewers measured ADC on all lesions and spleen. Receiver operating characteristics (ROC) analysis to differentiate NET from IPAS was performed and compared for absolute and normalised ADC. Inter-reader reliability for the two methods was assessed.
Pancreatic NET had significantly higher absolute ADC (1.431x10 vs 0.967x10 mm/s; P<0.0001) and normalised ADC (1.59 vs 1.09; P<0.0001) compared to IPAS. An ADC value of ≥1.206x10 mm/s was 70.6% sensitive and 90.9% specific for the diagnosis of NET vs. IPAS. Lesion to spleen ADC ratio of ≥1.25 was 80.4% sensitive, and 81.8% specific while ratio of ≥1.29 was 74.5% sensitive and 100% specific in the differentiation. The area under the curve (AUCs) for two methods were similar (88.2% vs. 88.8%; P=0.899). Both methods demonstrated excellent inter-reader reliability with ICCs for absolute ADC and ADC ratio being 0.957 and 0.927, respectively.
Both absolute and normalised ADC allow clinically relevant differentiation of pancreatic NET and IPAS.
• Imaging overlaps between IPASs and pancreatic-NETs lead to unnecessary procedures including pancreatectomy. • Uniquely low ADC of spleen allows differentiating IPASs from pancreatic NETs. • Both absolute-ADC and normalised-ADC (lesion-to-spleen ADC-ratio) demonstrate high accuracy in differentiating IPASs from NETs. • Both methods demonstrate excellent inter-reader reliability.
评估和比较绝对表观扩散系数（ADC）和标准化 ADC（病变与脾脏 ADC 比值）在鉴别胰腺神经内分泌肿瘤（NET）与胰内副脾（IPAS）中的准确性。
本研究纳入了 62 例胰腺 NET（n=51）或 IPAS（n=11）患者。两位独立的观察者对所有病变和脾脏进行 ADC 测量。采用受试者工作特征（ROC）分析比较绝对 ADC 和标准化 ADC 鉴别 NET 与 IPAS 的效果。评估两种方法的读者间信度。
与 IPAS 相比，胰腺 NET 的绝对 ADC（1.431x10 比 0.967x10 mm/s；P<0.0001）和标准化 ADC（1.59 比 1.09；P<0.0001）显著升高。当 ADC 值≥1.206x10 mm/s 时，诊断 NET 与 IPAS 的敏感性为 70.6%，特异性为 90.9%。病变与脾脏 ADC 比值≥1.25 时，敏感性为 80.4%，特异性为 81.8%；比值≥1.29 时，敏感性为 74.5%，特异性为 100%。两种方法的曲线下面积（AUC）相似（88.2%比 88.8%；P=0.899）。绝对 ADC 和 ADC 比值的 ICC 均显示出极好的读者间信度，分别为 0.957 和 0.927。
绝对 ADC 和标准化 ADC 均可在临床上对胰腺 NET 和 IPAS 进行有意义的鉴别。
• IPAS 与胰腺 NET 之间存在影像学重叠，导致不必要的手术，包括胰腺切除术。• 脾脏的独特低 ADC 可用于区分 IPAS 和胰腺 NET。• 绝对 ADC 和标准化 ADC（病变与脾脏 ADC 比值）在鉴别 IPAS 和 NET 中均具有较高的准确性。• 两种方法的读者间信度均较好。
