3D single point imaging with compressed sensing provides high temporal resolution R 2* mapping for in vivo preclinical applications

Abstract

Accelerated TurboSPI enables preclinical R * mapping without loss of data quality, and may show increased specificity to iron oxide compared to other sequences.

Using MRI cell tracking to monitor immune cell recruitment in response to a peptide‐based cancer vaccine

“…Quantitative information can also be obtained by using a pulse sequence such as TurboSPI . Originally designed for imaging water in porous media that have long values but short R 2 values, Rioux et al demonstrated that TurboSPI could also be applied to SPIO‐labeled cells, which exhibited similar magnetic properties .…”

“…Originally designed for imaging water in porous media that have long values but short R 2 values, Rioux et al demonstrated that TurboSPI could also be applied to SPIO‐labeled cells, which exhibited similar magnetic properties . Although TurboSPI traditionally requires long data acquisition times, the sequence was greatly accelerated for in vivo use by adding compressed sensing reconstruction . It is possible to extract maps from TurboSPI, which when combined with in vitro iron‐loading data allows generation of cellular density maps.…”

Cell density quantification with TurboSPI: R2* mapping with compensation for off-resonance fat modulation

“…Relaxation rate mapping is a popular method for attempting to quantify SPIO labeled cells, since R2* (R2* = 1/T2*) increases linearly as a function of cell density 14,15 . However, many R2* mapping techniques proposed to date are unable to resolve rapidly decaying signals restricting quantitative dynamic range, and prone to blooming artifacts induced by the very species which they are intended to quantify 16,17 .…”

“…Previous preclinical work done by our lab demonstrated the use of 3D TurboSPI, adapted for quantifying labeled cells 16,17 . TurboSPI is an accelerated multiecho single point imaging (SPI) sequence that was first developed for porous media with short T2* relaxation times (~1ms).…”

“…TurboSPI is an accelerated multiecho single point imaging (SPI) sequence that was first developed for porous media with short T2* relaxation times (~1ms). This sequence produces high temporal resolution data (sampled at ~100 kHz) which enables high fidelity R2* mapping with greater dynamic range and fewer artifacts due to the purely phase-encoded acquisition 16,17,21,22 .…”