Comparison of Dynamic and Liver-Specific Gadoxetic Acid Contrast-Enhanced MRI versus Apparent Diffusion Coefficients

Abstract

BackgroundHepatic lesions often present diagnostic connundrums with conventional MR techniques. Hepatobiliary phase contrast-enhanced imaging with gadoxetic acid can aid in the characterization of such lesions. However, quantitative measures describing late-phase enhancement must be assessed relative to their accuracy of hepatic lesion classification.Purpose: To compare quantitative parameters in gadoxetic acid contrast-enhanced dynamic and hepatobiliary phase imaging versus apparent diffusion coefficients in hepatic lesion characterization.Material and Methods57 patients with focal hepatic lesions on gadoxetic acid MR were included. Lesion enhancement at standard post-contrast time points and in the hepatobiliary phase (HB; 15 and 25 minutes post-contrast) was assessed via calculation of contrast (CR) and enhancement ratios (ER). Apparent diffusion coefficient (ADC) values were also obtained. Values for these parameters were compared among lesions and ROC analyses performed.Results: HB enhancement was greatest with FNH and adenomas. HB ER parameters but not HB CR could distinguish HCC from benign entities (0.9 ER ROC AUC versus 0.5 CR ROC AUC). There was no statistically significant difference found between the 15 and 25 minutes HB time points in detection of any lesion (p>0.4). ADC values were statistically significantly higher with hemangiomas (p<0.05) without greater accuracy in lesion detection relative to HB phase parameters.ConclusionHepatobiliary phase gadoxetic acid contrast-enhanced MR characterizes focal hepatic lesions more accurately than ADC and conventional dynamic post-contrast time point enhancement parameters. ER values are generally superior to CR. No discernible benefit of 25 minute versus 15 minute delayed imaging is demonstrated.

Intravoxel incoherent motion and dynamic contrast-enhanced MRI for differentiation between hepatocellular adenoma and focal nodular hyperplasia

“…10,11 Few other studies analysed D and/or ADC values of multiple benign and malignant liver lesions but could not find a significant difference between FNHs and HCAs. 25,26 In our study, we did find a significant difference for D but not for ADC. Discrepancies in reports of D and ADC in their ability to characterize liver lesions are well known.…”

“…The authors used a quantitative method, in which a significantly higher contrast ratio of FNHs was found than HCAs in the hepatobiliary phase after 15 and 25 min. 26 However, the long scanning time makes it less practical for clinical use. Our semi-quantitative analysis of the TICs reflecting the first pass of the contrast agent can be performed much faster (DCE-MRI scan time of 85 s after injection of contrast agent) but did not show a difference between both lesion types in our study.…”

Clinical Implications of Non-Steatotic Hepatic Fat Fractions on Quantitative Diffusion-Weighted Imaging of the Liver

“…DWI reflects the mobility of water molecules (molecular diffusion) in a tissue which can be described by the apparent diffusion coefficient (ADC) or the intravoxel incoherent motion (IVIM) model [4] – [6] . Since then DWI has been successfully applied in the assessment of focal liver lesions and diffuse liver diseases such as cirrhosis, fibrosis and steatosis [7] – [11] . However, the effect of fat on hepatic DWI is still subject of debate.…”

Distinguishing metabolic signals of liver tumors from surrounding liver cells using hyperpolarized 13C MRI and gadoxetate

“…28 The agent reaches "hepatobiliary phase" of maximal liver uptake approximately 10 to 15 min after injection of contrast. 29,30 In clinical MR imaging, T 1 -weighted images are usually acquired after this time to maximize the contrast between normal hepatocytes and liver metastases as well as hepatocellular carcinoma (90% of which lack the required transporter for gadoxetate 29 ). On a T 1 -weighted image, liver appears bright as compared to the hypointense tumor because contrast agent is taken up predominantly by hepatocytes.…”