Validation of the estimation of the macrovascular contribution in multi-timepoint arterial spin labeling MRI using a 2-component kinetic model

Purpose In this paper, the ability to quantify cerebral blood flow by arterial spin labeling (ASL) was studied by investigating the separation of the macrovascular and tissue component using a 2-component model. Underlying assumptions of this model, especially the inclusion of dispersion in the analysis, were studied, as well as the temporal resolution of the ASL datasets. Methods Four different datasets were acquired: (1) 4D ASL angiography to characterize the macrovascular component and to study dispersion modeling within this component, (2) high temporal resolution ASL data to investigate the separation of the 2 components and the effect of dispersion modelling on this separation, (3) low temporal resolution ASL dataset to study the effect of the temporal resolution on the separation of the 2 components, and (4) low temporal resolution ASL data with vascular crushing. Results The model that included a gamma dispersion kernel had the best fit to the 4D ASL angiography. For the high temporal resolution ASL dataset, inclusion of the gamma dispersion kernel led to more signal included in the arterial blood volume map, which resulted in decreased cerebral blood flow values. The arterial blood volume and cerebral blood flow maps showed overall higher arterial blood volume values and lower cerebral blood flow values for the high temporal resolution dataset compared to the low temporal resolution dataset. Conclusion Inclusion of a gamma dispersion kernel resulted in better fitting of the model to the data. The separation of the macrovascular and tissue component is affected by the inclusion of a gamma dispersion kernel and the temporal resolution of the ASL dataset.Cardiovascular Aspects of Radiolog

Time-encoded golden angle radial arterial spin labeling: simultaneous acquisition of angiography and perfusion data

The objective of the current study was to combine a time-encoded pseudocontinuous arterial spin labeling (te-pCASL) scheme with a golden angle radial readout for simultaneous acquisition of angiography and perfusion images from one single dataset, both in a highly flexible single-slice approach as well as within a multislice setting. A te-pCASL preparation and the golden angle radial readout were both used as a temporal resolution tool to retrospectively choose the temporal window for the reconstruction of both angiography and perfusion images from a single-slice dataset. The temporal window could be chosen retrospectively and adjusted to the hemodynamics of the volunteer on the scanner for the single-slice dataset. Angiographic images were reconstructed at a minimum temporal resolution of 69 ms. For the perfusion phase, only the densely sampled center of k-space was included in the reconstruction. For a multislice acquisition, the golden angle radial readout allowed reconstruction of images with different spatial resolutions to provide angiographic and perfusion information over 10 slices. The te-pCASL preparation was used as the only source for dynamic information. The multislice acquisition shows the ability of the golden angle radial readout to display the inflow of the labeled blood into the arteries as well as the perfusion in the tissue with full brain coverage. By combining a te-pCASL preparation with a golden angle radial readout, single-slice high temporal resolution angiography and good quality perfusion images were reconstructed in a flexible manner from a single dataset. Optimizing the golden angle radial readout for reconstructions at multiple spatial resolutions allows for multislice acquisition

Follow your label: simultanous 4D angiography and perfusion imaging by arterial spin labeling MRI

In this thesis, multiple approaches have been investigated for the simultaneous acquisition of 4D angiography and perfusion images using arterial spin labeling (ASL) MRI. Time-encoded pseudo-continuous (ASL) preparation was combined with multiple different readout modules, such as Look-Locker, Simultaneous multi-slice acquisition or a golden angle based non-Cartesian k-space trajectory to obtain high temporal resolution multi-time point data. These datasets were then used to improve the quantification of ASL signal and to obtain cerebral blood flow, arterial transit time and arterial blood volume maps. These quantitative maps hold the potential to provide important information in for example patients with stroke or Alzheimer’s disease. In addition, one of the assumptions within the two-component kinetic model to obtain these quantitative maps was investigated to study the separation of the macrovascular and perfusion component of the ASL signal. </p

Follow your label: simultanous 4D angiography and perfusion imaging by arterial spin labeling MRI

In this thesis, multiple approaches have been investigated for the simultaneous acquisition of 4D angiography and perfusion images using arterial spin labeling (ASL) MRI. Time-encoded pseudo-continuous (ASL) preparation was combined with multiple different readout modules, such as Look-Locker, Simultaneous multi-slice acquisition or a golden angle based non-Cartesian k-space trajectory to obtain high temporal resolution multi-time point data. These datasets were then used to improve the quantification of ASL signal and to obtain cerebral blood flow, arterial transit time and arterial blood volume maps. These quantitative maps hold the potential to provide important information in for example patients with stroke or Alzheimer’s disease. In addition, one of the assumptions within the two-component kinetic model to obtain these quantitative maps was investigated to study the separation of the macrovascular and perfusion component of the ASL signal. LUMC / Geneeskund