Physics Just the Basics Series #08 - Myocardial Perfusion Imaging: Principles and Methods-Perfusion

Video Transcription

Video Summary

The webinar introduced myocardial perfusion MRI, focusing on the physics and practical methods behind first-pass contrast-enhanced perfusion imaging. Markus Karlsson opened the session, then introduced Peter Kellman of NIH, who explained how gadolinium contrast is injected and tracked during its first pass through the right ventricle, left ventricle, and myocardium to reveal areas of reduced blood flow, especially during vasodilator stress.<br /><br />Kellman reviewed key MRI concepts such as T1 relaxation, saturation recovery, and why saturation-recovery imaging is widely used for perfusion. He discussed the trade-offs between image quality, temporal resolution, spatial resolution, and coverage, emphasizing that faster imaging improves motion robustness and reduces dark rim artifacts, while higher resolution improves detection of subendocardial defects.<br /><br />A major portion of the talk addressed artifacts and technical challenges, including Gibbs ringing, motion correction, coil intensity variation, and parallel imaging acceleration. He described how carefully designed saturation pulses, raw filtering, and motion correction improve image quality.<br /><br />The second half focused on quantitative perfusion. Kellman explained the need for accurate arterial input function estimation and how dual-bolus and dual-sequence approaches help overcome signal saturation and T2* effects. He outlined how signal data are converted into gadolinium concentration and fed into tissue models to generate pixel-wise myocardial blood flow maps.<br /><br />Examples showed how quantitative maps can better detect single-vessel, multivessel, and microvascular disease than visual assessment alone. In the Q&A, he noted that stress/rest protocols are usually kept consistent, that quantitative methods are more clinically useful than semi-quantitative upslope methods, and that half- to three-quarter-dose contrast is typically sufficient.

Keywords

myocardial perfusion MRI

first-pass contrast-enhanced imaging

gadolinium contrast

saturation recovery

vasodilator stress

image artifacts

motion correction

dual-bolus

quantitative perfusion

myocardial blood flow