Evaluating the Histopathology of Pancreatic Ductal Adenocarcinoma by Intravoxel Incoherent Motion-Diffusion Weighted Imaging Comparing With Diffusion-Weighted Imaging

Abstract

ObjectivesTo explore the differences between intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and diffusion-weighted imaging (DWI) in evaluating the histopathological characters of pancreatic ductal adenocarcinoma (PDAC).MethodsThis retrospective study enrolled 50 patients with PDAC confirmed by pathology from December 2018 to May 2020. All patients underwent DWI and IVIM-DWI before surgeries. Patients were classified into low- and high-fibrosis groups. Apparent diffusion coefficient (ADC), diffusion coefficient (D), false diffusion coefficient (D*), and perfusion fraction (f) were measured by two radiologists, respectively in GE AW 4.7 post-processing station, wherein ADC values were derived by mono-exponential fits and f, D, D* values were derived by biexponential fits. The tumor tissue was stained with Sirius red, CD34, and CK19 to evaluate fibrosis, microvascular density (MVD), and tumor cell density. Furthermore, the correlation between ADC, D, D*, and f values and histopathological results was analyzed.ResultsThe D values were lower in the high-fibrosis group than in the low-fibrosis group, while the f values were opposite. Further, no statistically significant differences were detected in ADC and D* values between the high- and low-fibrosis groups. The AUC of D and f values had higher evaluation efficacy in the high- and low-fibrosis groups than ADC values. A significant negative correlation was established between D values, and fibrosis and a significant positive correlation were observed between f values and fibrosis. No statistical difference was detected between DWI/IVIM parameters values and MVD or tumor cell density except for the positive correlation between D* values and tumor cell density.ConclusionsD and f values derived from the IVIM model had higher sensitivity and diagnostic performance for grading fibrosis in PDAC compared to the conventional DWI model. IVIM-DWI may have the potential as an imaging biomarker for predicting the fibrosis grade of PDAC.

Quantitative Magnetic Resonance Imaging for the Pancreas

“…100,102 In contrast, a significant positive correlation was detected in perfusion fraction (f ). 100,102 The differentiation of autoimmune pancreatitis from PDAC is challenging. Four studies reported a significantly smaller ADC in autoimmune pancreatitis than in PDAC, 77,[103][104][105] whereas 3 other investigations did not show a significant difference.…”

“…Two studies revealed a significant negative correlation of tumor fibrosis with pure diffusion (D) 100,102 . In contrast, a significant positive correlation was detected in perfusion fraction ( f ) 100,102 …”

“…They showed that the ADC was increased in loose fibrosis versus dense fibrosis and exhibited a negative correlation with the degree of fibrosis 100,101 . Two studies revealed a significant negative correlation of tumor fibrosis with pure diffusion (D) 100,102 . In contrast, a significant positive correlation was detected in perfusion fraction ( f ) 100,102 …”

Application of Magnetic Resonance Imaging in Neoadjuvant Treatment of Pancreatic Ductal Adenocarcinoma

“…This avoids the influence of cystic and vascular areas, which have a higher diffusion capacity of water molecules 33 on ADC values, which would misrepresent the true ADC values of tumor parenchymal areas. Meanwhile, Mannelli et al 34 and Liu et al 35 highlighted that small vision DWI can reduce artifacts and improve image resolution, resulting in an accurate ADC measurement. Therefore, sADC may be more representative of the ADC of the true pancreatic tumor microenvironment.…”

Use of Magnetic Resonance Imaging to Quantify Fat and Steatosis in the Pancreas in Patients after Bariatric Surgery: a Retrospective Study

“…IVIM DW imaging compensates for the downsides of traditional DWI because it is able to separate water molecule diffusion and microcirculatory perfusion-related diffusion. Changes in IVIM-derived parameters are associated with significant changes in advanced pancreatic fibrosis, which often accompanies pancreatic steatosis [22,32].…”