High‐resolution magnetic resonance angiography in the mouse using a nanoparticle blood‐pool contrast agent

High‐resolution magnetic resonance angiography is already a useful tool for studying mouse models of human disease. Magnetic resonance angiography in the mouse is typically performed using time‐of‐flight contrast. In this work, a new long‐circulating blood‐pool contrast agent—a liposomal nanoparticle with surface‐conjugated gadolinium (SC‐Gd liposomes)—was evaluated for use in mouse neurovascular magnetic resonance angiography. A total of 12 mice were imaged. Scan parameters were optimized for both time‐of‐flight and SC‐Gd contrast. Compared to time‐of‐flight contrast, SC‐Gd liposomes (0.08 mmol/kg) enabled improved small‐vessel contrast‐to‐noise ratio, larger field of view, shorter scan time, and imaging of venous structures. For a limited field of view, time‐of‐flight and SC‐Gd were not significantly different; however, SC‐Gd provided better contrast‐to‐noise ratio when the field of view encompassed the whole brain (P < 0.001) or the whole neurovascular axis (P < 0.001). SC‐Gd allowed acquisition of high‐resolution magnetic resonance angiography (52 × 52 × 100 micrometer³ or 0.27 nL), with 123% higher (P < 0.001) contrast‐to‐noise ratio in comparable scan time (～45 min). Alternatively, SC‐Gd liposomes could be used to acquire high‐resolution magnetic resonance angiography (0.27 nL) with 32% higher contrast‐to‐noise ratio (P < 0.001) in 75% shorter scan time (12 min). Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.