Final answer:
A CT scan with contrast dye is the primary imaging test used to diagnose pancreatic cancer, as it provides detailed images of the pancreas and its surrounding area.
Step-by-step explanation:
To diagnose pancreatic cancer, a Computed tomography (CT) scan with contrast dye is commonly used. This imaging test is effective at assessing the pancreas and can help identify complications such as fluid around the pancreas, abscesses, and pancreatic pseudocysts. Other tests, such as Magnetic resonance cholangiopancreatography (MRCP), an advanced form of MRI specifically for the bile ducts and pancreatic ducts, are also used in diagnosis, and Endoscopic ultrasound may be helpful when an invasive procedure might exacerbate the condition. It's important to note that while ultrasound is safe during pregnancy, detailed imaging of pancreatic tissue may not be its primary use-case.