The effect of gadoxetic acid enhancement on lesion detection and characterisation usingT₂weighted imaging and diffusion weighted imaging of the liver

Abstract

Objectives: To evaluate the effect of gadoxetic acid enhancement on the detection and characterisation of focal hepatic lesions on T 2 weighted and diffusion weighted (DW) images. Methods: A total of 63 consecutive patients underwent T 2 weighted and DW imaging before and after gadoxetic acid enhancement. Two blinded readers independently identified all of the focal lesions using a five-point confidence scale and characterised each lesion using a three-point scale: 1, non-solid; 2, indeterminate; and 3, solid. For both T 2 weighted and DW imaging, the accuracies for detecting focal lesions were compared using the free-response receiver operating characteristic analysis; the accuracies for lesion characterisation were compared using the McNemar test between non-enhanced and gadoxetic acid-enhanced image sets. For hepatic lesions >1 cm, the lesion-to-liver contrast-to-noise ratio (CNR) and the apparent diffusion coefficient (ADC) were compared in the non-enhanced and enhanced image sets using the generalised estimating equations. Results: For both T 2 weighted and DW images, the accuracies for detecting focal lesions (p>0.52) and those for lesion characterisation (p>0.63) did not differ significantly between the non-enhanced and enhanced image sets. The lesion-to-liver CNR was significantly higher on enhanced DW images than on non-enhanced DW images (p50.02), although the difference was not significant for T 2 weighted imaging (p50.65). The mean ADC values of lesions did not differ significantly on enhanced and non-enhanced DW imaging (p50.75). Conclusion: The acquisition of T 2 weighted and DW images after administration of gadoxetic acid has no significant effect on the detection or characterisation of focal hepatic lesions, although it improves the lesion-to-liver CNR on DW images. Various contrast agents have been developed and utilised for MRI of the liver in order to facilitate the detection and characterisation of focal hepatic lesions. Gadoxetic acid (gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid, PrimovistH; Bayer Schering Pharma, Berlin, Germany) is a recently developed, liverspecific contrast agent. As it has combined extracellular and hepatocyte-specific properties, gadoxetic acid can provide functional information regarding the cellular composition of focal hepatic lesions on hepatobiliary phase imaging as well as haemodynamic information on dynamic MRI following bolus injection. These properties of gadoxetic acid have been reported to improve the accuracy of liver MRI for lesion detection and characterisation [1][2][3][4][5][6][7].By contrast, these advantages of gadoxetic acidenhanced liver MRI are obtained with increased examination time, as delayed scanning approximately 20 min after contrast administration is necessary for optimal hepatobiliary phase imaging [4,5,[7][8][9]. Among the pulse sequences commonly acquired for clinical liver MRI, T 2 weighted and diffusion weighted (DW) imaging are frequently performed using a respiratory-triggered method in order to improve image quality...

Diagnosis of focal liver lesions with gadoxetic acid‐enhanced MRI: Is a shortened delay time possible by adding diffusion‐weighted imaging?

“…In addition, higher interobserver agreement with 20‐min set than with other sets suggests the reproducibility of this approach. Given DWI or T2‐weighted image acquired after administration of gadoxetic acid is reportedly comparable to precontrast one . A shortened protocol can be adopted by introducing DWI and T2WI during the interval between the 3‐min late phase and 20‐min HBP.…”

Liver lesion detection and characterization: Role of diffusion‐weighted imaging

“…That suggests that the acquisition of DWI during the interval between dynamic MRI and hepatobiliary phase can be effective and time‐saving, without degrading image quality. Concentration of Gd‐EOB‐DTPA in the hepatic parenchyma leads to an approximately 16% decrease of liver SNR on postcontrast DWI, with no significant effects on detecting FLL (72) and even an improvement of conspicuity of FLLs and lesion‐to‐liver contrast compared with precontrast DWI (75).…”

Magnetic Resonanance Imaging of the Liver (Including Biliary Contrast Agents)—Part 2: Protocols for Liver Magnetic Resonanance Imaging and Characterization of Common Focal Liver Lesions

“…96 These effects on tissue signal can vary depending on CM concentration and the image acquisition time (more or less than ~ 10 minutes since injection). 96,97 …”

“…However, signal intensity, CNR, and ADC values of liver lesions do not change significantly, with minor effects on lesion detection. 97–99 In our institution, when Gd-EOB-DTPA is used, all T2-weighted and DWI images are acquired after contrast injection. Because of the high incidence of postinjection transient dyspnea (14% of patients) and truncation artifacts associated with the use of Gd-EOB-DTPA, a slow injection rate and acquisition of multiple arterial phases with techniques oversampling the central portion of the k-space is preferred (Table 2).…”