Imaging of indeterminate pancreatic cystic lesions: a systematic review

Pancreatic cystic lesions are an increasing problem and investigation of these cysts can be fraught with difficulty. There is currently no gold standard for diagnosis or surveillance. This review was undertaken to determine the present reliability of the characterisation, assessment of malignant potential and diagnosis of pancreatic cystic lesions using available imaging modalities.

A Medline search using the terms 'pancreatic', 'pancreas', 'cyst', 'cystic', 'lesions', 'imaging', 'PET'. 'CT', 'MRI' and 'EUS' was performed. Publications were screened to include studies examining the performance of CT, MRI, MRCP, EUS and 18-FDG PET in the determination of benign or malignant cysts, cyst morphology and specific diagnoses.

Nineteen studies were identified that met the inclusion criteria. 18-FDG PET had a sensitivity and specificity of 57.0-94.0% and 65.0-97.0% and an accuracy of 94% in determining benign versus malignant cysts. CT had a sensitivity and specificity of 36.3-71.4% and 63.9-100% in determining benign disease but had an accuracy of making a specific diagnosis of 39.0-44.7%. MRI had a sensitivity and specificity of 91.4-100.0% and 89.7% in assessing main pancreatic duct communication.

CT is a good quality initial investigation to be used in conjunction with clinical data. MRCP can add useful information regarding MPD communication but should be used judiciously. PET may have a role in equivocal cases to determine malignancy. Further examination of CT-PET in this patient group is warranted.