Representative arterial cerebral blood volume (aCBV) maps from the same subject as shown in Fig 6.

<p>The values in the color scale bar are displayed in the unit of mL/100 mL.</p

Comparison of estimated arterial cerebral blood volumes (aCBVs) (Mean ± SD^*) between bSSFP model and T₁ model (N = 6).

<p>Comparison of estimated arterial cerebral blood volumes (aCBVs) (Mean ± SD^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156687#t002fn002" target="_blank">*</a>}) between bSSFP model and T₁ model (N = 6).</p

Diagram for segmented multiphase bSSFP sequence.

<p>(a) Initial 10 phase encoding scans with linearly increasing flip angles were discarded as dummy scans. Each measurement consisted of 288 phase encoding steps, which were subdivided into nine K-space datasets with 32 phase encoding lines per dataset. Since each K-space reflected different stage of flow dynamics, nine dynamic phases could be obtained. In order to fill 96 phase encoding lines per K-space, three measurements were performed. (b) ALADDIN acquisition scheme was composed of sequential ascending and descending orders, which were alternated in every measurement. Therefore, six measurements were needed to complete nine K-space datasets in both ascending and descending orders.</p

The estimated values from two proposed models.

<p>Perfusion parameters. ATT: traveling time from a labeling plane to an imaging slice, F: arterial flow parameter, δ: transit time from the arterial compartment to the capillary/tissue compartment in imaging slice. All values represented in the form of Mean ± SD^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156687#t001fn001" target="_blank">*</a>} were measured in gray matter from ALADDIN with multiphase bSSFP readout fitted to bSSFP model and T₁ model.</p

Monte Carlo simulation results for the bSSFP model.

<p>The error percentage of the mean (indicating the accuracy) (<b>a</b>) and the coefficient of variation (indicating the precision) (<b>b</b>) are shown as a function of the signal-to-noise ratio (SNR) that ranged from 5 to 20 with a step size of 5.</p

Simulation results of magnetization difference between control and labeling scans in sagittal sinus vein.

The simulations were performed at various flip angles (FA) (30, 40, 50, and 60°) (a), various inter-slice delay time (TD) (0, 250, and 500 ms) (b), and various gap size (200, 300, 400, and 500% of slice thickness) (c). ΔM represents magnetization difference between control and labeling scans and M represents the signal intensity of control scan.</p

A representative dataset of multiphase ALADDIN with different gap sizes (300% and 450% of slice thickness) and different inter-slice delay time (TD) (0 and 500 ms) from one representative subject.

<p>(a) The enlarged perfusion-weighted images at the first phase. (b) The perfusion-weighted images from the multiple phases. The time phase of perfusion-weighted images is marked on top of each column. Scan time for 0-ms TD and 500-ms TD was 4.9 min and 6.5 min, respectively.</p

Representative aCBV maps of ALADDIN with multiphase bSSFP and AVAST.

<p>Estimated aCBV maps of ALADDIN with four different conditions and AVAST are shown, and the values in the gray scale bar are displayed in the unit of mL/100 mL.</p

Simulation results of magnetization difference between control and labeling scans with two flow rates (0.2 and 5 cm/s) for ALADDIN with multiphase bSSFP sequence.

<p>The simulations were performed at ATT of 1500 ms (a), 500 ms (b), and 100 ms (c). The red and blue lines represent the flow rates of 0.2 cm/s and 5 cm/s, respectively. The solid and broken lines represent the results for fitting to bSSFP model and T₁ model, respectively. ΔM represents magnetization difference between control and labeling scans. a.u. represents arbitrary unit.</p

Feasibility of quantifying arterial cerebral blood volume using multiphase alternate ascending/descending directional navigation (ALADDIN)

In this study, we evaluated the feasibility of a new 2D inter-slice bSSFP-based arterial spin labeling (ASL) technique termed, alternate ascending/descending directional navigation (ALADDIN), to quantify aCBV using multiphase acquisition in six healthy subjects. As a result of fitting to the proposed model, aCBV values in gray matter  were in good agreement with those from literature