Vascular contrast studies, also known as angiograms, are crucial for diagnosing obstructions of the cardiovascular system. Vascular contrast imaging studies are typically used to diagnose highmorbidity and high-mortality conditions, including coronary artery disease, atherosclerosis and stroke. Vascular contrast agent studies are also used to diagnose and stage cancer, relying on the fact that abnormal neovasculature of tumours are more permeable to small-molecular-weight contrast

20.1 Introduction .......................................................................................................................... 523 20.2 Overview of Current Angiography Methods and Contrast Agents ...................................... 524

20.2.1 Catheterised X-Ray Angiography ............................................................................. 524 20.2.2 CT Angiography ....................................................................................................... 524 20.2.3 Contrast MRA .......................................................................................................... 525 20.2.4 Toxicity of Current Contrast Agents for Chronic Kidney Disease Patients ............. 525

20.3 Magnetic Particle Imaging ................................................................................................... 526 20.3.1 MPI Method .............................................................................................................. 526 20.3.2 MPI with Harmonic Decomposition and System Matrix Reconstruction ............... 527 20.3.3 x-Space Analysis of MPI .......................................................................................... 528

20.4 Fundamental Sensitivity, Contrast, Penetration and Resolution ........................................... 530 20.4.1 Sensitivity Comparison to MRI ................................................................................ 530 20.4.2 Contrast/Penetration ................................................................................................. 530 20.4.3 Artefacts ................................................................................................................... 530 20.4.4 Resolution ................................................................................................................. 530

20.5 Hardware: The 3D Berkeley MPI Mouse Scanner ............................................................... 531 20.6 Data from the Berkeley MPI Scanners ................................................................................. 531

20.6.1 Sensitivity ................................................................................................................. 531 20.6.2 Linearity ................................................................................................................... 532 20.6.3 Phantom Images ....................................................................................................... 532 20.6.4 Penetration and Contrast ........................................................................................... 532

20.7 Tailored MPI Contrast Agents, Relaxation and Characterisation ........................................ 533 20.8 Conclusion ............................................................................................................................ 535 Acknowledgements ........................................................................................................................ 536 References ...................................................................................................................................... 536

agents. The most common contrast agents in use today are iodine for x-ray and computerised tomography (CT) and gadolinium for magnetic resonance imaging (MRI). The principal challenges with current contrast agent studies include ionising radiation (x-ray and CT), weak contrast with a venous injection, invasive catheterised delivery (x-ray) and the risk of damaging kidneys1-3, especially for patients with poor renal function.