Quantified ADC histogram analysis: a new method for differentiating mass-forming focal pancreatitis from pancreatic cancer

Abstract

Background

As their prognosis and management are different, differentiation of mass-forming focal pancreatitis (FP) from pancreatic adenocarcinoma (PC) is important. However, the similar clinical presentations and imaging features of these conditions, along with inconclusive biopsy results can make such differentiation difficult.

Purpose

To determine whether apparent diffusion coefficient (ADC) histogram analysis can discriminate between a normal pancreas, FP, and PC.

Material and Methods

In a retrospective study, 25 PC patients, 14 FP patients, and 25 subjects with a normal pancreas underwent breath-hold diffusion-weighted imaging (DWI) on a 3.0 T magnetic resonance (MR) scanner. Regions of interest (ROIs) were drawn on the normal pancreases and on the entire focal lesions of both PC and FP. The ADC value was averaged from the lowest to 10th, 30th, 50th, and 100th percentile of the histogram (i.e. ADC₁₀, ADC₃₀, ADC₅₀, and ADC₁₀₀, respectively), and the results were analyzed statistically.

Results

There were no significant differences among the head, body, and tail of normal pancreases for any of the mean ADC values (P > 0.05). ADC₁₀, ADC₃₀, and ADC₅₀ values demonstrated significant differences between lesion and non-lesion areas of both PC (P < 0.05) and FP (P < 0.05). Differences in lesion areas between PC and FP were found with ADC₅₀ and ADC₁₀₀ values (P < 0.05), and helped differentiate a normal pancreas from FP and PC, and FP from PC.

Conclusion

Quantified ADC histogram can specifically reflect tissue heterogeneity and help differentiate a normal pancreas from FP and PC.