Before pancreatic surgery, MRI and CT answer different questions

Design

Systematic review and meta-analysis of 40 direct head-to-head comparative imaging studies

Population

Patients with suspected pancreatic ductal adenocarcinoma undergoing at least two imaging methods

Primary outcome

Pooled sensitivity and specificity by modality for detection and staging

Effect

Liver metastases MRI 0.89/0.91 vs CT 0.60/0.84; resectability specificity CT 0.88 vs MRI 0.63

Pancreatic ductal adenocarcinoma has a narrow therapeutic window, so pre-operative imaging has to be right. This meta-analysis of 40 direct comparative studies asked which modality does what best, using pathology as the reference where available.

For detecting the primary tumour, CT, MRI and endoscopic ultrasound performed similarly. The modalities diverged on staging: MRI was markedly more sensitive and specific for liver metastases (sensitivity 0.89, specificity 0.91) than CT (0.60 and 0.84), while CT was more specific for assessing resectability (0.88 versus MRI 0.63) and better for vascular invasion; endoscopic ultrasound was most sensitive for lymph nodes.

The practical consequence is that these are complementary, not competing. Before potentially curative surgery, a dedicated liver MRI adds value by ruling out small metastases that would change the plan, while CT remains the backbone for mapping resectability and other metastatic sites. Reaching for one alone risks missing what the other sees.

• CT, MRI and endoscopic ultrasound detected the primary pancreatic tumour similarly well.
• MRI was more sensitive and specific for liver metastases (0.89 / 0.91) than CT (0.60 / 0.84).
• CT was more specific for resectability (0.88 vs MRI 0.63) and better for vascular invasion; endoscopic ultrasound best for lymph nodes.
• Add a dedicated liver MRI before curative pancreatic surgery to exclude small metastases, with CT for resectability and other sites.

Why it matters

It replaces a single-modality habit with a task-matched protocol that changes whether small metastases are caught before surgery.

Don't overread it

Pooled estimates came from heterogeneous comparative studies with wide confidence intervals — the direction is clear, the exact figures less so.

The statistics, in plain English

Sensitivity is how well a test catches disease that is present; specificity is how well it avoids false positives. MRI's higher sensitivity for liver metastases means it misses fewer small lesions, while CT's higher specificity for resectability means it less often wrongly calls a tumour unresectable.

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