Diffusion‐weighted imaging: Effects of intravascular contrast agents on apparent diffusion coefficient measures of breast malignancies at 3 tesla

Abstract

Purpose To determine whether apparent diffusion coefficient (ADC) measures of breast lesions at 3 tesla (T) are affected by gadolinium administration. Materials and Methods The study included 19 patients who underwent 3T MRI. Diffusion-weighted imaging (DWI) was acquired with b=0, 100, and 800 s/mm2 before and after a dynamic contrast-enhanced (DCE) sequence. ADC values were measured for each lesion and normal fibroglandular tissue. Pre and post-contrast ADC measures were compared by Wilcoxon signed-rank test, and differences between groups were compared by Mann-Whitney U test; p<0.05 was considered statistically significant. Results There was no significant difference in pre and post-contrast ADC measured at b=0,100,800 s/mm2 for malignancies (median change: −0.4%,−0.01×10−3 mm2/s, p=0.40), but there was a slight increase in post-contrast ADC in normal tissue (+1.6%,+0.04×10−3 mm2/s, p=0.0006). Findings were similar for both lesions (−0.4%,−0.01×10−3 mm2/s, p=0.54) and normal tissue (+1.5%,+0.03×10−3 mm2/s, p=0.002) with ADC measured at b=0,800 and also at b=100,800 s/mm2 (lesions: +0.9%,+0.01×10−3 mm2/s, p=0.71; normal tissue: +1.8%,+0.03×10−3 mm2/s, p=0.005). For lesions, results were not affected by lesion size, type (mass vs. non-mass enhancement), mean initial enhancement, late enhancement, or delayed enhancement rate on DCE-MRI (p>0.05 for all). Normal tissue showed some trends with greater progressive enhancement rates and higher late enhancement levels correlating with greater increase in post-contrast ADC (p=0.09 for both). Conclusions Our results show that breast lesion ADC measures using our approach were not significantly altered following DCE-MRI at 3T, suggesting DWI and DCE-MRI can be performed in any order without affecting diagnostic criteria. However, influences of contrast on ADC measures in normal breast tissue were observed and require further investigation.

Diffusion Weighted Magnetic Resonance Imaging of the Breast

“…The influence of contrast administration on DWI is controversial with some studies demonstrating little effect 11,49-51 and others suggesting that the effect may be tissue specific and dependent on image timing after contrast administration 52-56 . Our own data shows that ADCs increase significantly after DCE-MRI in both malignant and normal tissue at 3T, but this effect can be neutralized by using normalized ADCs (see below) 57 . The reason for the observed ADC change requires further investigation.…”

“…ADC normalization may reduce variation from individual breast characteristics and technical factors such as whether DWI is performed pre- or post-contrast 57 . Normalized ADC is calculated as: $$\mathrm{nADC}={\mathrm{ADC}}_{\text{lesion}}∕{\mathrm{ADC}}_{\text{normal}}$$ where ADC lesion and ADC normal are the mean ADC of the lesion and normal breast parenchyma tissue, respectively.…”

DWI in the Assessment of Breast Lesions

“…Overall, the influence of contrast agent administration on breast lesion ADC measures was determined to be negligible [50, 51], particularly when DWI is acquired several minutes post-contrast [51], and either approach is acceptable.…”

Clinical Breast MR Using MRS or DWI: Who Is the Winner?

“…When added to CE-MRI, DWI sequences showed a significant diagnostic gain: the summary ROC-AUC of CE-MRI combined with DWI was 0.94 compared with 0.85 for CE-MRI alone (2). Differently from 1H-MRS, contrast injection does not negatively impact on DWI performance (51); ADC measures were reported to not significantly change following DCE-MRI at 3 T, suggesting that DWI and DCE-MRI can be performed in any order without affecting diagnostic performance (52). Moreover, Janka et al showed that DWI after contrast injection even leads to a slightly better benign/malignant discrimination (53).…”