Gadoxetate disodium is a widely used magnetic resonance (MR) contrast agent for liver MR imaging, and it provides both dynamic and hepatobiliary phase images. However, acquiring optimal arterial phase images at liver MR using gadoxetate disodium is more challenging than using conventional extracellular MR contrast agent because of the small volume administered, the gadolinium content of the agent, and the common occurrence of transient severe motion. In this article, we identify the challenges in obtaining high-quality arterial-phase images of gadoxetate disodium-enhanced liver MR imaging and present strategies for optimizing arterial-phase imaging based on the thorough review of recent research in this field.

Objective To compare the conspicuity of hepatocellular carcinoma (HCC) on hepatobiliary phase of gadoxetate disodium-enhanced vs. delayed phase of gadodiamide-enhanced MR images, relative to liver function. Methods and materials We retrospectively identified 86 patients with newly diagnosed HCC between 2010 and 2013 and recorded the severity of liver disease by Child-Pugh class (CPC). 38 patients had gadodiamide-enhanced 5-min delayed and 48 had gadoxetate disodium-enhanced 20-min delayed hepatobiliary MR images. The conspicuity of 86 HCCs (mean size, 2.7 cm) was graded visually on a 3-point scale and quantified by liver-to-tumor contrast ratios (LTC). The relative liver parenchymal enhancement (RPE) was measured. For different CPCs, we compared the conspicuity of HCC and RPE between gadodiamide and gadoxetate. Results In patients with CPC A, the visual conspicuity and LTC of the 27 HCCs imaged with gadodiamide were significantly lower than those of the 38 HCCs with gadoxetate (P < 0.01, <0.01, respectively). RPE was lower in gadodiamide scans than gadoxetate scans (P < 0.01). Conversely, in patients with CPC B and C, HCCs appeared more frequently as definite hypointensity when imaged with gadodiamide (72.7%, 8/11) than gadoxetate (20%, 2/10, P = 0.03). LTC (mean 18.1 vs. 7.5, P = 0.04) and RPE (mean 75.5 vs. 45.4, P = 0.04) was significantly higher in the gadodiamide than gadoxetate scans. Conclusion In patients with compromised liver function, hypointensity of HCC is more conspicuous in the gadodiamide delayed phase than the gadoxetate hepatobiliary phase. This likely reflects the high extracellular accumulation of gadodiamide and poor hepatocyte uptakeof gadoxetate in patients with compromised liver function.

SummaryWe assessed the prevalence of abdominal aortic calcification (AAC) in older living kidney donors and its effect on recipient eGFR and graft histology. A total of 292 consecutive living pairs with donor age ≥50 from 2003 to 2013 were identified (mean age 56; range 50-78; F/M: 1.8). Donor AAC was determined by prenephrectomy unenhanced CT. Recipient eGFR and spot urine protein: creatinine ratios (UPCRs) were recorded. A total of 180 recipients had 6-month protocol biopsies. AAC was present in 40.7% of donors, and they were older (58.6 versus 54.7 years old, P < 0.0001) and more likely to be male (77.6% vs. 37.3%, P = 0.004). There was no significant difference in eGFR or spot UPCR up to 36 months in recipients of allografts from donors with versus without AAC. At 6-month biopsy, there was a higher percentage of allografts with vascular fibrous intimal thickening and arteriolar hyaline thickening from donors with versus without AAC (vascular fibrous intimal thickening: 38.8% vs. 7.1% and arteriolar hyaline thickening: 35.8% vs. 7.1%; P < 0.001 for both). The presence of donor AAC predicts the presence of vascular disease [vascular fibrous intimal thickening (OR: 7.2; CI:2.9-17.9) and arteriolar hyaline thickening (OR:5.7; CI:2.3-14.1)] in allografts at 6 months. Donor AAC is predictive of renal vascular disease and may help to improve the screening of potential donors and inform post-transplant management.