Improving ungated steady-state cardiac perfusion using transition bands.

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Imaging Physics

Background:

• Gated first-pass contrast-enhanced sequences are standard for cardiovascular MR perfusion.
• Ungated steady-state sequences are necessary for some patients but prone to errors from cardiac motion and blood flow.
• Existing methods may contain quantification errors due to disrupted magnetization steady state.

Purpose of the Study:

• To eliminate tissue magnetization steady-state disruption in ungated cardiovascular MR perfusion imaging.
• To improve perfusion quantification accuracy in challenging patient conditions.
• To introduce a sequence modification without altering resolution or timing parameters.

Main Methods:

• Simultaneously exciting two transition bands adjacent to the imaged region.
• Using gradient dephasing and radiofrequency spoiling to null transition band signals.
• Integrating transition bands into a 2D ungated steady-state radial FLASH sequence with simultaneous multiband imaging on a PRISMA 3T MRI scanner.

Main Results:

• Transition bands effectively reduce magnetization steady-state disruption without introducing artifacts.
• Myocardial blood flow maps show good uniformity and consistency with literature values.
• Perfusion estimates align well with saturation-recovery methods.

Conclusions:

• The proposed transition bands reduce quantification errors from blood flow and motion.
• Image acquisition efficiency and temporal resolution remain unchanged.
• This technique offers a viable solution for accurate ungated cardiovascular MR perfusion imaging.