Contrast agent influences MRI phase-contrast flow measurements in small vessels.

• Contrast-enhanced MR angiography is often combined with phase contrast (PC) flow measurement to answer a particular clinical question. The contrast agent that is administered during contrast-enhanced MR angiography may still be present in the blood during the consecutive PC flow measurement. The aim of this work was to evaluate the influence of contrast agent on PC flow measurements in small vessels. For that purpose, both in vivo measurements and computer simulations were performed. The dependence of the PC flow quantification on the signal amplitude difference between blood and stationary background tissue for various vessel sizes was characterized. Results show that the partial-volume effect strongly affects the accuracy of the PC flow quantification when the imaged vessel is small compared to the spatial resolution. A higher blood-to-background-contrast level during imaging significantly increases the partial-volume effect and thereby reduces the accuracy of the flow quantification. On the other hand, a higher blood-to-background-contrast level facilitated the segmentation of the vessel for flow rate determination. PC flow measurements should therefore be performed after contrast agent administration in large vessels, but before contrast agent administration in small vessels.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)

Keyword

magnetic resonance imaging

phase-contrast

spatial resolution

contrast agent

spatial resolution

Publication and Content Type

ref (subject category)

art (subject category)