Double Contrast Media enhanced MRI with Ferumoxides-Gadolinium on Hepatocellular Carcinoma

PURPOSE: To evaluate the effects of Ferumoxides on Gadolinium (Gd) enhanced dynamic liver magnetic resonance imaging (MRI) in cirrhotic patients and also for the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: 29 patients with liver cirrhosis were examined at 1.5T. 12 patients had HCC. The imaging protocol included GE T1 in and opposed phases, and a breath-hold TSE T2 before and 30-60 min following 0.05 ml/kg Ferumoxides. Four dynamic in-phase GE series were also acquired after an injection of 20 ml of Gd at 2 ml/sec. SNR and CNR were calculated for liver lesion relative to the muscle and background liver respectively. Statistical analysis was performed using the paired t-test. RESULTS: The SNR of the liver decreased by 8.6+/-1.20 (p<0.001) after Ferumoxides injection. At the peak of the Gd effect, the liver increased by 6.09+/-1.15 relative to the post Ferumoxides, but it was not significantly different from the pre-Ferumoxides study (p<0.01). Although there was no significant change in post Ferumoxides SNR of HCC, CNR of HCC relative to the liver increased by 7.54+/-1.61 (p<0.05). After the Gd injection, CNR of HCC increased by 15.6+/-3.87 (p<0.05). CONCLUSION: The administration of Ferumoxides made HCC CNR increase, and it canceled the effect of Gd enhancement of the cirrhotic liver. The combination of Ferumoxides and Gd makes HCC CNR increase.

Usefulness of Digital Subtraction Technique in the Contrast-enhanced Multi-phasic Abdominal MR angiography

PURPOSE: To assess the usefulness of digital subtraction contrast-enhanced multi-phase magnetic resonance angiography (MRA) for evaluation of the vessels of the gastrointestinal system. MATERIALS AND METHODS: Twenty-five patients who underwent abdominal MRA for evaluation of the vessels of the gastrointestinal system were included in this study. MRA was performed using a 1.5-T scanner and the 3-D turbo-FLASH sequence. Subtraction images of the arterial and portal venous phases were obtained by subtracting arterial phase images from mask images and portal venous phase images from arterial phase images, respectively. Each set of images was processed using a maximum-intensity projection (MIP) algorithm to produce three-dimensional angiograms. We compared overall image quality and the visibility of normal and abnormal vessels between subtraction and non-subtraction MRA. RESULTS: In terms of subjective image quality, subtraction and non-subtraction MRA was similar both the arterial and portal venous phases (p>0.05). During the arterial phase, subtraction MRA visualized more peripheral branches of the left gastric and superior mesenteric arteries than non-subtraction MRA (p<0.05), and during the portal venous phase, subtraction MRA demonstrated more peripheral branches of the superior mesenteric (p<0.01), splenic (p<0.05) and left portal vein (p<0.05) than non-subtraction MRA. In addition, overall visibility of the arterial and portal venous branches was superior with subtraction MRAs than with non-subtraction MRA. Both of these detected all anomalous arterial branching (n=5) and abnormal (encased or obstructed) portal veins (n=5). Subtraction MRA visualized 17 portal venous collaterals in six patients, whereas non-subtraction MRA visualized only seven collateral veins. CONCLUSION: In contrast-enhanced abdominal MRA, the digital subtraction technique permits visualization of more distal branches of the vessels of both the arterial and portal venous systems without significant degradation of image quality. The technique is particularly useful for the detection of portal venous collaterals in patients with portal hypertension.