Added value of apparent diffusion coefficient in distinguishing between serous and mucin-producing pancreatic cystic neoplasms.

OBJECTIVES: To evaluate the added value of diffusion-weighted imaging (DWI) on MRI in differentiating serous from mucin-producing pancreatic cystic neoplasms (PCNs).

METHODS: One hundred seventeen patients with PCN measuring ≥ 10 mm were included. Three readers independently evaluated MRI with and without the use of apparent diffusion coefficient (ADC). Logistic regression was used to analyze whether confidence scores were different with the use of different image sets. Diagnostic performance with and without ADC was compared.

RESULTS: DWI/ADC improved confidence in 44.8%, 73.6%, and 78.2% of patients by the three readers in distinguishing serous from mucin-producing PCNs. The use of ADC increased the probability of a higher confidence in the differentiation as compared to morphological imaging for all three readers (p < 0.001). Odds ratio for increase in the diagnostic confidence with the use of ADC for the three readers with decreasing years of experience were 5.8, 6.8, and 12.7. The diagnostic accuracy of morphological MRI with ADC was higher than that without ADC for two of three readers with lesser experience (87.2% vs. 80.8%; 91.5% vs. 80.8%).

CONCLUSION: DWI may have added value as a complementary tool to conventional morphological MRI in differentiating between serous and mucin-producing PCNs with possibly greater value for readers with less experience in reading abdominal MRI.

KEY POINTS: • Optimal management of PCNs requires differentiation of serous from mucin-producing PCNs. • ADC measurements allow increased confidence in differentiating serous from mucin-producing PCNs. • ADC measurements increase the accuracy in diagnosing serous versus mucin-producing PCNs.