Brain iron has been previously found elevated in the substantia nigra pars compacta (SNpc), but not in other brain regions, of Parkinson’s disease (PD) patients. However, iron in circulation has been recently observed to be lower than normal in PD patients. The regional selectivity of iron deposition in brain as well as the relationship between SNpc brain iron and serum iron within PD patients has not been completely elucidated. In this pilot study we measured brain iron in six regions of interest (ROIs) as well as serum iron and serum ferritin, in 24 PD patients and 27 age- gender- matched controls. Brain iron was measured on magnetic resonance imaging (MRI) with a T2 prime (T2’) method. Difference in brain iron deposition between PD cases and controls for the six ROIs were calculated. SNpc / white matter brain iron ratios and SNpc/ serum iron ratios were calculated for each study participant, and differences between PD patients and controls were tested. PD patients overall had higher brain iron than controls in the SNpc. PD patients had significantly higher SNpc / white matter brain iron ratios than controls, and significantly higher brain SNpc iron / serum iron ratios than controls. These results indicate that PD patients’ iron metabolism is disrupted toward a higher partitioning of iron to the brain SNpc at the expenses of iron in the circulation.

Purpose Maximization of the BOLD fMRI contrast requires TE of the MR sequence to match the T2* value of the tissue of interest, which is expected to be higher in the fetal brain compared to a child or an adult. Methods T2* values of the cortical plate/cortical grey matter tissue in utero in healthy fetuses from mid-gestation onwards (20–36 GW) were measured using 3D T2* maps calculated from 2D dual-echo T2*-w data corrected for between-slice motion and reconstructed in 1.0 mm3 isotropic resolution from a sequence of multiple time points, together with 1.0 mm3 isotropic resolution T2-w structural data. Results Mean T2* relaxation times of the cortical tissue were about two times higher than previously reported in adults. In a supporting single seed analysis experiment default mode and auditory networks appeared better localized and less noisy while using TE=100 ms versus TE=43 ms. The results of the previous study reporting a trend for T2* values to decrease with fetal age were reproduced and extended to include subjects in earlier gestation (20–26 GW) and cortical tissues. Conclusions The first measurement of T2* values in fetal cortical tissues suggested the appropriate TE range for fetal BOLD fMRI protocol optimization to be 130–190 ms.

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Motion correction of MRI sequences is a very active area of research. Several postprocessing techniques for volume correction and more recently slice correction have been proposed. Slice motion correction of fMRI data typically involves iterative registration of slices to a target volume. The target volume is usually reconstructed at each iteration using current slice motion estimates, with all possible views of the subject. However, in the presence of large movements, the quality of the reconstruction can be greatly degraded without a good initialization, and this can in turn greatly affect the accuracy and precision of the slice registration. This paper introduces a cascaded motion correction pipeline that uses subsets of data to generate coherent volumes for initial target volume based slice registration in fMRI. The pipeline incorporates distortion correction, frame motion estimation and two levels of slice to volume registration. The proposed method has been tested on moving adult and fetal fMRI data.

Recently, there has been considerable interest, especially for in-utero imaging, in the detection of functional connectivity in subjects whose motion cannot be controlled while in the MRI scanner. These cases require two advances over current studies: 1) multi-echo acquisitions and 2) post processing and reconstruction that can deal with significant between slice motion during multi-slice protocols to allow for the ability to detect temporal correlations introduced by spatial scattering of slices into account. This paper focusses on the estimation of a spatially and temporally regular time series from motion scattered slices of multi-echo fMRI datasets using a full 4D iterative image reconstruction framework. The framework which includes quantitative MRI methods for artifact correction, is evaluated using adult studies with and without motion to both refine parameter settings and evaluate the analysis pipeline. ICA analysis is then applied to the 4D image reconstruction of both adult and in-utero fetal studies where resting state activity is perturbed by motion. Results indicate quantitative improvements in reconstruction quality when compared to the conventional 3D reconstruction approach (using simulated adult data), and demonstrate the ability to detect the default mode network in moving adults and fetuses with single-subject and group analysis.