A 4D time resolved MRA pulmonary MRI exam can help diagnose and urgent matter and even save somebody’s life when done correctly. One of the most important issues about doing an MRA of the lungs is the contrast bolus timing is captured successfully.

The example shared below was performed several years ago, and could be one portion of a typical Pulmonary MRA study.   The images shown are the “four dimensional” or 4D time resolved MRA Pulmonary study with the patient holding their breath after instructions were given. Four Dimensional refers to the three planes we live in (X, Y and Z) plus time, the fourth dimension.

The time resolved portion allows the viewer to witness the flow of MRI contrast from the right heart and into the pulmonary arteries, pass through the lungs and into the pulmonary veins.  This is accomplished by performing very fast 3D sequences one immediately after another in a high field MRI system.  The 4D time resolved MRA pulmonary sequence can be the first of two separate sequences, where a portion of the contrast is used for this sequence, and the rest of the contrast is used for a secondary high resolution breath hold standard Pulmonary MRA. Acquisition timing in catching the contrast at the optimal location in relation to the interested anatomy is critical, and requires coaching, skill and practice.


Since the contrast passes through the pulmonary system very quickly, it becomes important to catch the contrast bolus during the actual timing with capturing the images, while coaching the patient to hold their breath at the moment the images are acquired.  Timing and practice are critical, with excellent instructions given to the patient, and full understanding by the patient before any portion of the contrast is administered for the 4D time resolved MRA pulmonary.

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4d time resolved mra pulmonary