Projection-based respiratory-resolved left ventricular volume measurements in patients using free-breathing double golden-angle 3D radial acquisition

Abstract

Objective To refine a new technique to measure respiratory-resolved left ventricular end-diastolic volume (LVEDV) in mid-inspiration and mid-expiration using a respiratory self-gating technique and demonstrate clinical feasibility in patients. Materials and methods Ten consecutive patients were imaged at 1.5 T during 10 min of free breathing using a 3D golden-angle radial trajectory. Two respiratory self-gating signals were extracted and compared: from the k -space center of all acquired spokes, and from a superior–inferior projection spoke repeated every 64 ms. Data were binned into end-diastole and two respiratory phases of 15% respiratory cycle duration in mid-inspiration and mid-expiration. LVED volume and septal–lateral diameter were measured from manual segmentation of the endocardial border. Results Respiratory-induced variation in LVED size expressed as mid-inspiration relative to mid-expiration was, for volume, 1 ± 8% with k -space-based self-gating and 8 ± 2% with projection-based self-gating ( P = 0.04), and for septal–lateral diameter, 2 ± 2% with k -space-based self-gating and 10 ± 1% with projection-based self-gating ( P = 0.002). Discussion Measuring respiratory variation in LVED size was possible in clinical patients with projection-based respiratory self-gating, and the measured respiratory variation was consistent with previous studies on healthy volunteers. Projection-based self-gating detected a higher variation in LVED volume and diameter during respiration, compared to k -space-based self-gating.

Fetal 3D cardiovascular cine image acquisition using radial sampling and compressed sensing

“…Two golden means from the Fibonacci series were used to calculate the azimuthal and polar angle of each radial spoke. To balance both a uniform k‐space coverage and eddy current artifacts, the fifth pair of golden means from the Fibonacci series was chosen (ie, $$$ {\phi}_1\approx 1.26{}^{\circ} $$$ and $$$ {\phi}_2\approx 0.58{}^{\circ} $$$) 20,21 . Both the azimuthal and polar angle completed a full rotation (ie, they were both defined between 0° and 360°), to minimize step size between successive spokes and thereby decrease eddy current artifacts 22 .…”

“…To balance both a uniform k‐space coverage and eddy current artifacts, the fifth pair of golden means from the Fibonacci series was chosen (ie, and ). 20 , 21 Both the azimuthal and polar angle completed a full rotation (ie, they were both defined between 0° and 360°), to minimize step size between successive spokes and thereby decrease eddy current artifacts. 22 A slab‐selective excitation pulse in the maternal feet–head direction was implemented to reduce signal from spins outside the FOV.…”