Exploratory high b value diffusion-weighted MR for quantitative differentiation of ileocecal inflammatory conditions and tumors.

OBJECTIVES

To explore the quantitative analysis of high b value (2000 s/mm) diffusion-weighted imaging (DWI) for the differentiation of ileocecal inflammatory conditions and tumors, compared with conventional b value (800 s/mm) DWI.

METHODS

Sixty-six patients with 30 tumors and 36 inflammatory conditions underwent MR enterography with conventional and high b values DWI. Quantitative apparent diffusion coefficient (ADC) values and signal intensity ratios (SIRs) of lesions of the psoas muscle were measured from the two b value DWIs. The receiver operating characteristic (ROC) curve was applied to determine the diagnostic value of ADC and SIR for differentiating tumors from inflammatory conditions.

RESULTS

The ADC values of tumors were significantly lower than those of inflammatory conditions in 800 s/mm (p = 0.001) and 2000 s/mm (p < 0.001) DWI. In addition, tumors exhibited significantly higher SIR values compared to inflammatory conditions (p < 0.001 in 800 s/mm and 2000 s/mm DWI). Areas under the curve (AUC) of ADC and SIR derived from high b value (0.828 for ADC, 0.947 for SIR) were superior to those from conventional b value DWI (0.731 and 0.849, respectively). Compared to ADC, SIR values achieved better AUCs in both two b values DWI.

CONCLUSIONS

Quantitative ADC values and SIR could be used as non-invasive tools to distinguish ileocecal tumors from inflammatory conditions. The use of high b value DWI would improve this ability. Furthermore, SIR obtained from high b value DWI was the most promising quantitative parameter.

CRITICAL RELEVANCE STATEMENT

This study indicated that quantitative DWI parameters might be applied as non-invasive imaging biomarkers for distinguishing bowel tumors from inflammatory conditions. The SIR from high b value DWI could improve the differentiation, providing invaluable information for establishing appropriate therapeutic strategies.

KEY POINTS

Differentiation between bowel inflammatory conditions and tumors is still a dilemma. Quantitative DWI contributed to distinguishing ileocecal tumors from inflammatory conditions. SIR from DWI is a promising parameter for differentiating these pathologies.