Intensity Correction in Intravascular MRI using Projection Images

Introduction: Potential clinical benefits of high-resolution imaging using intravascular probes is often limited due to the image intensity distortion caused by the signal inhomogeneity associated with the placement of the probe. Methods developed for the phased-array and other surface coils are not as successful for intravascular imaging since the conducting structures of the RF-receiving device are placed in the central area of the image which often changes shape and orientation with respect to the static field between acquisitions. Image based approaches that attempt to extract the coil sensitivity profile based on filtering techniques need not necessarily preserve low frequency information in the images. A more direct approach is a one that corrects the image by dividing it with the intensity profile computed using the inverse square law. We find this analytical method is a better approach when the shape and placement information of the probe can be conveniently obtained using projection images of the probe.