Ultrasound-driven cardiac MRI. (February 2020)

• Record Type: Journal Article
• Authors: Santini, Francesco; Gui, Laura; Lorton, Orane; Guillemin, Pauline C.; Manasseh, Gibran; Roth, Myriam; Bieri, Oliver; Vallée, Jean-Paul; Salomir, Rares; Crowe, Lindsey A.
• Is Part Of: Physica medica. Volume 70(2020)
• Page Start: 161
• Page End: 168
• Publication Date: 2020-02
• Subjects: Cardiac MRI -- Ultrasound -- Slice following -- Free-breathing navigation; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2020.01.008
• Languages: English
• ISSNs: 1120-1797

Abstract

Graphical abstract: Highlights: Organ motion is a challenge in MRI. Ultrasound imaging can capture this motion in real time with high spatial resolution. Ultrasonography and MRI can be performed simultaneously. This information can be used to update the MR acquisition in real time. Abstract: Purpose: One of the challenges of cardiac MR imaging is the compensation of respiratory motion, which causes the heart and the surrounding tissues to move. Commonly-used methods to overcome this effect, breath-holding and MR navigation, present shortcomings in terms of available acquisition time or need to periodically interrupt the acquisition, respectively. In this work, an implementation of respiratory motion compensation that obtains information from abdominal ultrasound and continuously adapts the imaged slice position in real time is presented. Methods: A custom workflow was developed, comprising an MR-compatible ultrasound acquisition system, a feature-motion-tracking system with polynomial predictive capability, and a custom MR sequence that continuously adapts the position of the acquired slice according to the tracked position. The system was evaluated on a moving phantom by comparing sharpness and image blurring between static and moving conditions, and in vivo by tracking the motion of the blood vessels of the liver to estimate the cardiac motion. Cine images of the heart were acquired during free breathing. Results: In vitro, the predictive motion correction yielded significantly better results than non-predictive or non-corrected acquisitions (p ≪ 0.01). In vivo, the predictive correction resulted in an image quality very similar to the breath-hold acquisition, whereas the uncorrected images show noticeable blurring artifacts. Conclusion: In this work, the possibility of using ultrasound navigation with tracking for the real-time adaptation of MR imaging slices was demonstrated. The implemented technique enabled efficient imaging of the heart with resolutions that would not be feasible in a single breath-hold.