Ma Wanling, Zhang Guangwen, Ren Jing, Pan Qi, Wen Didi, Zhong Jinman, Zhang Zhuoli, Huan Yi
Department of Radiology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Quant Imaging Med Surg. 2018 Apr;8(3):301-310. doi: 10.21037/qims.2018.04.08.
The aim of this study was to compare intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) parameters such as standard apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudodiffusion coefficient (D) and perfusion fraction (ƒ) for differentiating pancreatic ductal adenocarcinoma (PDAC) with different pathological grades.
Institutional Review Board of our hospital approved this study protocol. Subjects comprised 38 PDACs confirmed by pathology. Pancreatic multiple b values DWI with 15 b values of 0, 10, 20, 40, 60, 80, 100, 150, 200, 400, 800, 1,000, 1200, 1,500, and 2,000 s/mm was performed using GE Discovery MR750 3.0T scanner. ADC, D, D and ƒ values of all PDACs were calculated using mono- and bi-exponential models. Parameters of well/moderately differentiated and poorly differentiated PDAC were compared using Independent Sample -test. P values <0.05 were considered significant.
Mean D value of well/moderately differentiated PDAC was significantly lower than that of poorly differentiated PDAC (0.540×10 0.676×10 mm/s, P<0.001). Mean ƒ value of well/moderately differentiated PDAC was significantly higher than that of poorly differentiated PDAC (60.3% 38.4%, P<0.001). The area under curve value of ƒ in differentiating well/moderately differentiated PDAC from poorly differentiated PDAC was slightly higher than that of D (0.894>0.865). When the D value was less than or equal to 0.599×10 mm/s, the sensitivity and specificity were 100% and 84.6% respectively. When ƒ value was greater than 49.6%, the sensitivity and specificity were 92.0% and 84.6% respectively.
D and ƒ derived from IVIM-DWI model can be used to distinguish well/moderately differentiated PDAC from poorly differentiated PDAC. And to serve this purpose, D and ƒ have high diagnostic performance. IVIM-DWI is a promising and non-invasive tool for predicting pathological grade of PDAC.
本研究旨在比较体素内不相干运动扩散加权成像（IVIM-DWI）参数，如标准表观扩散系数（ADC）、纯扩散系数（D）、伪扩散系数（D*）和灌注分数（ƒ），以鉴别不同病理分级的胰腺导管腺癌（PDAC）。
我院机构审查委员会批准了本研究方案。研究对象包括38例经病理证实的PDAC患者。使用GE Discovery MR750 3.0T扫描仪对胰腺进行多b值DWI检查，b值分别为0、10、20、40、60、80、100、150、200、400、800、1000、1200、1500和2000 s/mm²。采用单指数和双指数模型计算所有PDAC的ADC、D、D*和ƒ值。采用独立样本t检验比较高/中分化和低分化PDAC的参数。P值<0.05被认为具有统计学意义。
高/中分化PDAC的平均D值显著低于低分化PDAC（0.540×10⁻³ vs 0.676×10⁻³ mm²/s，P<0.001）。高/中分化PDAC的平均ƒ值显著高于低分化PDAC（60.3% vs 38.4%，P<0.001）。ƒ在鉴别高/中分化与低分化PDAC时的曲线下面积值略高于D（0.894>0.865）。当D值小于或等于0.599×10⁻³ mm²/s时，敏感性和特异性分别为100%和84.6%。当ƒ值大于49.6%时，敏感性和特异性分别为92.0%和84.6%。
IVIM-DWI模型得出的D和ƒ可用于区分高/中分化PDAC与低分化PDAC。为此，D和ƒ具有较高的诊断性能。IVIM-DWI是预测PDAC病理分级的一种有前景的非侵入性工具。
