Comparison of different diffusion parameters in DWI for differentiation of breast lesions at 3.0 Tesla – Effects of perfusion and diffusion compartments on ADC

In one-hundred-thirty-nine ROIs the following mean ADC values were found when fitting intensities of all bvalues (29 cysts/ 17 benign/ 24 malignant/ 69 healthy; 2.63±0.37, 1.47±0.21, 0.99±0.18, and 1.85±0.20 mm2/s). Significant ADC differences were found for all types by ANOVA (p<.05). Lowest ADC was found for malignant lesions. Malignant and benign tumors were differentiated with 96% sensitivity and 94% specificity by an ADC threshold of 1.25 x10-3mm2/s. The same sensitivity/specificity was achieved for a two b-value combination. The optimal threshold was linearly decreasing for increasing b-value of combinations. Using low maximum b-values leads to overestimation of ADC (compartment effects) in all tissues but cysts (i.e.: ADC of 0/400 is ~26% higher than for 0/1000 in malignant lesions). An error of ±10% in the threshold was decreasing the specificity to 76% or sensitivity to 79%, respectively. Higher minimum b-values were additionally suppressing perfusion effects. For tumors a maximum CNR was found for 850 s/mm2. The difference in CNR compared to neighbouring b-values was significant in benign/malignant lesions (p<.05), but not significant for malignant lesions when compared to b=1000 x10-3mm2/s (p=.118). While benign lesions exhibited an average 26% higher CNR than malignant lesions at 0 s/mm2, the mean CNR at 850 s/mm2 was 22% higher for malignant lesions than for benign. Investigations of the CV showed an increase of the precision for up to 850 Comparison of different diffusion parameters in DWI for differentiation of breast lesions at 3.0 Tesla – Effects of perfusion and diffusion compartments on ADC