What is the imaging modality of choice for the pancreas?

From the Guidelines

The imaging modality of choice for evaluating the pancreas is contrast-enhanced computed tomography (CT), particularly multi-detector CT with both arterial and venous phase imaging. This recommendation is based on the most recent and highest quality study available, which highlights the importance of CT in diagnosing and staging pancreatic cancer 1. CT provides excellent visualization of pancreatic parenchyma, surrounding structures, and vascular anatomy with high spatial resolution.

For optimal pancreatic imaging, a typical protocol includes non-contrast images followed by contrast administration with arterial phase (45-50 seconds) and venous phase (70 seconds) acquisitions, as suggested by the American College of Radiology 1. This approach allows for detection of hypervascular tumors in the arterial phase and hypovascular lesions in the venous phase.

Some key points to consider when choosing an imaging modality for the pancreas include:

• The ability to detect small lesions and characterize cystic lesions
• The need to assess biliary and pancreatic ducts
• The importance of evaluating vascular invasion by tumor
• The availability and speed of the imaging modality

Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) serves as an excellent complementary or alternative modality, particularly for evaluating cystic lesions, detecting small tumors, and assessing biliary and pancreatic ducts without radiation exposure 1. Endoscopic ultrasound (EUS) offers superior resolution for small lesions and allows for tissue sampling but is more invasive and operator-dependent 1.

The choice between these modalities depends on the specific clinical question, with CT generally preferred for initial evaluation due to its widespread availability, speed, and comprehensive assessment capabilities 1.

From the Research

Imaging Modalities for the Pancreas

The imaging modality of choice for the pancreas depends on the specific clinical scenario.

• For incidentally discovered pancreatic cysts, CT and MRI are the imaging modalities of choice to guide clinical management 2.
• In the evaluation of pancreatic adenocarcinoma, CT is recommended for initial imaging assessment, with an accuracy of 0.73 compared to 0.70 for MR imaging 3.
• CT is also considered the primary modality for the evaluation of patients with pancreatic disease, although pitfalls can occur in interpretation and additional imaging techniques may be necessary 4.

Comparison of Imaging Modalities

• A review of the literature found that multi-detector computed tomography (MDCT) and MRI/MRCP have comparable sensitivity and specificity rates for diagnosis and staging of pancreatic cancers 5.
• Endoscopic ultrasonography (EUS) offers the best sensitivity and specificity rates for lesions <2 cm, and is recommended for assessing lesions not clearly detected on CT/MRI 5.
• PET-CT can be useful in ruling out distant metastases in locally advanced lesions 5.

Practical Approach to MRI of the Pancreas

• A practical approach to MRI of the pancreas involves using a combination of T1, T2-weighted, MRCP, and fat-suppressed T1-weighted dynamic post-gadolinium SGE sequences to detect and characterize pancreatic diseases 6.
• MRI is reserved for specific indications, including the detection of small and non-organ-deforming pancreatic ductal adenocarcinoma, islet cell tumors, and choledocholithiasis 6.