Superparamagnetic iron oxide‐enhanced liver MRI with SHU 555 A (RESOVIST®): New protocol infusion to improve arterial phase evaluation—A prospective study

Abstract

Purpose:To compare the arterial enhancement of hypervascular hepatic lesions by T1-weighted 3D-GRE (gradientrecalled echo) fat-sat sequence after slow (0.5 mL/sec) and fast (2 mL/sec) RESOVIST infusion. Materials and Methods:We prospectively enrolled 71 patients with hypervascular hepatic lesions to undergo dynamic magnetic resonance imaging (MRI) examination with RESOVIST. A total of 92 benign and malignant lesions, 44 of which histologically confirmed, were examined. Three blinded and independent readers visually assessed the arterial enhancement using a score from 0 (none) to 3 (maximum), the latter score comparable to that achievable by MultiHance administration. Results:Out of the 92 hypervascular lesions, 41, 31, and 20 nodules were examined using the slow, fast, and both protocols, respectively. Relevant enhancement (scores 2-3) was found in 42% vs. 14.5% of cases for slow and fast protocols, respectively. Intraindividual comparison evaluation confirmed the better results obtained by slow than fast protocol (25% vs. 10%), with statistically relevant difference in distribution of scores (P ϭ 0.0004). The slow protocol showed values between 0 and 3 with an arithmetic mean of 1.1; the fast one, on the other hand, showed values between 0 and 2 with an arithmetic mean of 0.66. Conclusion FERUCARBOTRAN (RESOVIST, SHU 555 A, BayerSchering Pharma, Berlin, Germany) is a contrast agent (CA) composed of superparamagnetic iron oxide (SPIO) particles. RESOVIST allows a potential improvement in diagnostic capability compared with the first-generation SPIO CAs such as ferumoxide (ENDOREM Guerbet, Aulnay-sous-Bois, France, and Feridex). Due to a large distributed particle size, ranging from 21-60 nm (1,2), the mean hydrodynamic diameter of ferucarbotran is smaller than that of ferumoxide particles, 60 versus 150 nm, respectively. Particles are coated with carboxydextran (rather than dextran, as in ferumoxide) which ensures aqueous solubility and prevents aggregation.Ferumoxide is infused slowly to avoid lumbar pain and hypotensive reaction. Conversely, RESOVIST does not cause side effects after rapid intravenous injection, therefore allowing dynamic examination and, similar to ferumoxide, reticulo-endothelial system (RES) specific imaging in the delayed phase (3). RESOVIST is taken up by phagocytic Kupffer cells of the liver (80%), spleen (8%-10%) (4), bone marrow, and lymph nodes (10%). Following uptake by Kupffer cells, a decrease in signal intensity (SI) can be seen in tissues that take up RESO-VIST (5). Generally, iron oxide particles are used as negative enhancers because they have a high R 2 /R 1 relaxivity ratio, meaning that the effect on T2 shortening is generally much stronger than that on T1 shortening. As the particles are taken up by Kupffer cells in the liver, the T2 effect becomes the dominant mechanism due to accumulation of the CA at higher concentrations. Therefore, RESOVIST induces a decrease in SI in lesions that contain phagocytic cells (benign lesions) or a significant blood-pool (hemangiomas) on T2-

Resovist enhanced MR imaging of the liver: Does quantitative assessment help in focal lesion classification and characterization?

“…2). This last finding is in contrast with a prior study with slow bolus Resovist administration, where the best enhancement achievable did not seem related to a particular category of focal lesion and was appreciable in all histological types with the same evidence (18). However, the previous experience was performed with a qualitative approach, and we believe that lesion changes are more appreciable by quantitative evaluation, which is easy and rapid to obtain by the proposed method, rather than by visual qualitative evaluation which often misjudges the enhancement, in particular on the T2‐weighted acquisition, in our opinion because of the strong rescaling phenomenon induced by Resovist administration (Figs.…”

“…One possible explanation for the different contrastographic features identified may be due to the typical enhancement of hemangiomas and FNHs during dynamic acquisition, usually less transient than the enhancement shown in adenomas and HCCs. Generally, we can confirm the minor conspicuity upon dynamic evaluation of hypervascular lesions after Resovist administration versus gadolinium chelates CA, despite the adoption of the slow infusion protocol, noted in a prior study (18).…”

“…Resovist was administered in a bolus by prefilled syringe (dose 0.9 mL in patients with a body weight lower than 60 kg, and 1.4 mL higher than 60 kg) in the distal part of a connecting line into an antecubital vein, followed by flushing with 20 mL of saline solution using an automated injector (Spectris Solaris EP, MedRad, Indianola, PA), at the rate of 0.5 mL/s to obtain a wider window of enhancement (18). The duration of the entire administration (CA plus 20 mL saline flush) was approximately 40–42 s. To avoid too great a difference in the administered CA quantity among various sized patients, we adopted an empirical rule, limiting the dose to 1.2 mL until the weight of 75 kg.…”

“…Some authors (16, 17) have reported dissatisfaction with SPIO arterial phase after bolus injection in clinical practice. A new protocol has been proposed to improve the enhancement in dynamic phase (at the rate of 0.5 mL/s against the usual rate of 2 mL/s) (18).…”

Safety and efficacy of rituximab in patients with hepatitis C virus–related mixed cryoglobulinemia and severe liver disease

“…Unenhanced examinations were repeated after slow administration of Resovist (SHU-555A; Bayer Schering Pharma), a superparamagnetic iron oxide contrast agent, as previously shown. 28 A simple quantitative analysis of percentage of signal intensity changes of cirrhotic liver parenchyma, in delayed phases (10 minutes of acquisition), after contrast agent administration, was performed. [29][30][31] The dose of 0.9 or 1.4 mL of SHU-555A was administered in patients whose body weight was below or greater than 60 kg, respectively (range, 7.0-12.9 mol iron/kg).…”