Diffusion Weighted MRI Compared to Ultrasound Elstography in the Assessment of Pancreatic Masses.

There are many types of pancreatic masses classified based on their nature (benign vs. malignant), type (solid vs. cystic), and histological characteristics such as pancreatic cysts, pseudocysts with pooled prevalence rate of 8%,, pancreatic ductal carcinoma (PDAC) accounts for more than 85%, neuroendocrine tumors (NET) less than 5%, and solid pseudopapillary neoplasms account for approximately 0.9%-2.7% of all exocrine pancreatic neoplasms and 5% of cystic pancreatic neoplasms. Moreover, there are some pancreatic tumorous diseases such as chronic pancreatitis and autoimmune pancreatitis .

Pancreatic cancer has a low 5-year relative survival rate of 9% .Unfortunately, the global incidence of pancreatic ductal adenocarcinoma (PDAC) is increasing by about 1% annually Presently, PDAC is the seventh leading cause of cancer-related mortality in the world, with more than 300,000 deaths reported each year.

Typically, imaging assessment is the initial process in the diagnosis of PDAC. Endoscopic ultrasonography (EUS) and/or endoscopic retrograde pancreatography may be considered as reliable tools with higher diagnostic ability. However, because of the recent trend of reducing patient burden while ensuring safety, less-invasive methods may be preferred for practical management.

Currently, the commonly used imaging examinations for pancreatic lesions include computed tomography (CT) and magnetic resonance imaging (MRI). However, despite tremendous advances in imaging, it is still challenging to accurately characterize some pancreatic lesions based on morphological imaging, such as identifying small lesions and differentiating pancreatic adenocarcinoma and mass-forming pancreatitis which represents about 5-10% of pancreatic mass cases.

Diffusion weighted imaging (DWI) is an MRI method that provides information about the microstructural characteristics of tissues by detecting the random molecular motion of water molecules and generates representative ADC values.