Rapid volumetric t₁ mapping of the abdomen using three‐dimensional through‐time spiral GRAPPA

Abstract

Purpose To develop an ultrafast T1 mapping method for high-resolution, volumetric T1 measurements in the abdomen. Methods The Look-Locker method was combined with a stack-of-spirals acquisition accelerated using 3D through-time spiral GRAPPA reconstruction for fast data acquisition. A segmented k-space acquisition scheme was proposed and the time delay between segments for the recovery of longitudinal magnetization was optimized using Bloch equation simulations. The accuracy of this method was validated in a phantom experiment and in vivo T1 measurements were performed with 35 asymptomatic subjects on both 1.5 T and 3 T MRI systems. Results Phantom experiments yielded close agreement between the proposed method and gold standard measurements for a large range of T1 values (200 to 1600 ms). The in vivo results further demonstrate that high-resolution T1 maps (2×2×4 mm3) for 32 slices can be achieved in a single clinically feasible breath-hold of approximately 20 s. The T1 values for multiple organs and tissues in the abdomen are in agreement with the published literature. Conclusion A high-resolution 3D abdominal T1 mapping technique was developed, which allows fast and accurate T1 mapping of multiple abdominal organs and tissues in a single breath-hold.

Recent advances in parallel imaging for MRI

“…Through-time non-Cartesian GRAPPA has been used to collect real-time cardiac data without breathholds or electrocardiogram gating in 45ms per 2D frame with radial sampling (Figure 12) [70,82] and 35ms per frame with spiral sampling [71]. Non-Cartesian GRAPPA has also been applied for renal MRA [72], myocardial [83] and liver perfusion [84], and abdominal T 1 mapping [85]. Late gadolinium enhancement (LGE) cardiac imaging with a 3D spiral trajectory has been accelerated using SPIRiT to enable whole-heart coverage in one breathhold [86].…”

Feasibility of through‐time spiral generalized autocalibrating partial parallel acquisition for low latency accelerated real‐time MRI of speech

“…With the known weights, it performs a frame‐by‐frame linear reconstruction to estimate the missing k‐space samples in every coil. Through‐time non‐Cartesian GRAPPA has been applied and evaluated in several dynamic and relaxometry MRI applications, including real‐time cardiac MRI , renal MRI angiography , liver perfusion MRI , and T 1 mapping . Here, we evaluate it to efficiently exploit the acceleration capabilities offered by a custom eight‐channel upper‐airway coil and spiral trajectories for dynamic upper‐airway imaging.…”

Single breath‐hold 3D cardiac T1 mapping using through‐time spiral GRAPPA

“…In this study, rapid 3D T 1 mapping was achieved by collecting accelerated spiral data and reconstructing images with through‐time spiral GRAPPA. This technique was originally proposed for free‐breathing 2D cardiac imaging, and has found widespread use in multiple 3D applications, including breath‐hold 3D cardiac perfusion imaging, free‐breathing whole‐liver perfusion imaging and 3D abdominal T 1 mapping . In this study, a 3D cardiac T 1 mapping technique was developed, which allows fast and accurate T 1 mapping of the heart in a single short breath‐hold.…”

“…All of the image reconstruction was implemented off‐line using MATLAB (The Mathworks, Natick, MA, USA) on a standalone desktop computer (Intel Xeon E3–1270 quad‐core CPUs at 3.4 GHz and 16 GB of RAM). The undersampled spiral data were reconstructed using 3D through‐time spiral GRAPPA, as described previously . In brief, the 3D through‐time spiral GRAPPA reconstruction consists of two major steps.…”

“…However, most techniques still require multiple long breath‐holds or successful respiratory triggering to acquire a limited number of slices (typically five to six). Recently, a rapid 3D T 1 mapping method for the abdomen has been developed, which uses the Look–Locker technique in combination with the through‐time spiral generalized autocalibrating partially parallel acquisition (GRAPPA) acceleration technique . In this study, this mapping technique has been expanded to enable rapid volumetric T 1 mapping for the heart.…”