Self-gated 3D FLASH imaging of the human lung under free breathing using DC signals

Introduction Multiple air-tissue interfaces and the intrinsically low proton density make human lung MRI challenging. Additionally, motion artefacts due to respiration or blood flow can degrade image quality and restrict the acquisition time. There are several techniques to avoid respiratory motion artefacts. External measurement devices such as an ECG or a respiration belt can be applied to synchronise data acquisition with motion [1]. Navigator echoes can be acquired to monitor respiratory and cardiac motion [2]. This method needs additional RF pulses which saturates parts of the imaged volume and extent the acquisition time. A time-efficient concept is to use the DC signal for self-gating [3-5]. In this work, examinations of the human lung were performed during free respiration using the DC signal for self-gating. The acquisition of the DC signal was implemented into a 3D FLASH sequence and high resolution images were reconstructed retrospectively. The advantages are that neither external measurement devices nor additional RF Pulses for respiratory gating were needed.