However, increasing the contrast agent dose is not feasible or practical for iodinated contrast agents in CT because of their inherent nephrotoxicity. Runge ( 14) previously demonstrated a significant increase in tumor-to-liver tissue conspicuity (as assessed by the contrast-to-noise ratio (CNR)) when the IV-injected Gd dose was increased from 0.1 to 0.3 mmol/kg in a rabbit model of liver cancer. One possible way to detect small HCC lesions is to increase the dose of contrast agent injected during a radiologic imaging examination. Thus, the traditional IV method of contrast agent delivery is inadequate for reliably detecting small HCC lesions. Reported sensitivity values for CT range from 70–80% ( 11- 13), and MRI sensitivity of 84% was observed in a study with IV administered contrast agents ( 9). The detection of small HCC lesions (<2 cm), however, remains a challenge. Overall, MRI appears to be superior for detecting HCC ( 7- 10). In 50 cirrhotic patients, Burrel et al ( 9) showed that CE-MRI provided superior sensitivity compared to dynamic helical CT for detecting HCC (76% vs. The sensitivity of CE-MRI for detecting HCC is 62–77% ( 6- 8). CE magnetic resonance imaging (MRI) with IV injection of T1-shortening gadolinium chelate (Gd) contrast agent is the most commonly used MRI method to detect HCC. However, CE CT exposes patients to ionizing radiation and potentially nephrotoxic contrast agents. Contrast-enhanced (CE) helical computed tomography (CT) with intravenous (IV) administration of iodinated contrast agent is the most commonly used radiologic imaging modality for the detection of HCC. © 2006 Wiley-Liss, Inc.ĮARLY DETECTION OF HEPATOCELLULAR CARCINOMA (HCC) ( 1- 3) (i.e., small or isolated lesions) while the patient is asymptomatic and has adequate liver function can improve the chances for successful surgical ( 4) or palliative radiofrequency ablation (RFA) ( 5) therapy. This strategy could be employed to enhance the detection of small liver tumors or to conserve contrast agent in future MRI-guided transcatheter liver therapies. We demonstrated the feasibility of using IA injection techniques to improve tumor conspicuity. For six of the eight tumors the IA SNR was greater than the IV SNR, but statistical significance was not achieved due to the small sample size of the study ( P = 0.07). The IA CNR was significantly greater than the IV CNR ( P 60% increase in CNR for each tumor. The peak SNR and CNR were 21.7 ± 5.8 and 17.0 ± 4.8 (mean ± SD) after IA injection, and 16.9 ± 10.2 and 6.2 ± 2.6 after IV injection. Peak enhancement (signal-to-noise ratio (SNR)) and conspicuity (contrast-to-noise ratio (CNR)) were measured for each acquisition. After positioning a catheter in the hepatic artery, we performed 3D inversion recovery GRE MRI after IA and IV gadopentetate-dimeglumine contrast injections at doses of 0.04 and 0.1 mmol/kg, respectively. Materials and MethodsĮight VX2 liver tumors were grown in five rabbits. To test the hypothesis that catheter-directed intraarterial (IA) contrast agent injection increases tumor enhancement and conspicuity compared to intravenous (IV) injection.
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