Evaluation of Gadopiclenol and P846, 2 High-Relaxivity Macrocyclic Magnetic Resonance Contrast Agents Without Protein Binding, in a Rodent Model of Hepatic Metastases: Potential Solutions for Improved Enhancement at Ultrahigh Field Strength

Purpose The aim of this study was to evaluate in vitro and in vivo the enhancement properties of experimental gadolinium (Gd)-based contrast agents (GBCAs) with different molecular weights and hydration numbers (P846 and gadopiclenol) compared with clinically approved low-molecular, extracellular agents (gadopentetate and gadoterate) at 9.4 T and to discuss influencing factors on r1 relaxivities. Methods and Materials All experiments were performed with a 9.4 T animal scanner (Bruker, Germany). We performed relaxometry measurements for all contrast agents in human plasma at 37°C using an IR-RARE sequence. In addition, we compared P846 with gadopentetate and gadopiclenol with gadoterate intraindividually in rats with hepatic colorectal cancer metastases (n = 10 each) acquiring T1-weighted FLASH sequences before and at 10 consecutive time points during 20 minutes. After intravenous contrast agent application, signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), and lesion enhancement (LE) for liver parenchyma and tumors were calculated based on region of interest measurements. Results Longitudinal relaxivities (r1) of the low-molecular agents were lower as compared with the experimental compounds. However, r1 of gadopentetate and gadoterate demonstrated only a moderate decrease of r1 at 9.4 T as compared with known data at lower field strengths (gadopentetate: r1 [at 9.4 T], 3.4 mM−1 s−1/r1 [at 1.5 T], 4.1 mM−1 s−1/gadoterate: r1 [at 9.4 T], 3.1 mM...
Source: Investigative Radiology - Category: Radiology Tags: Original Articles Source Type: research