Purpose:To investigate the feasibility of high temporal resolution breast DCE-MRI using compressed sensing theory. Methods: Two experiments were designed to investigate the feasibility of using reference image based compressed sensing ͑RICS͒ technique in DCE-MRI of the breast. The first experiment examined the capability of RICS to faithfully reconstruct uptake curves using undersampled data sets extracted from fully sampled clinical breast DCE-MRI data. An average approach and an approach using motion estimation and motion compensation ͑ME/MC͒ were implemented to obtain reference images and to evaluate their efficacy in reducing motion related effects. The second experiment, an in vitro phantom study, tested the feasibility of RICS for improving temporal resolution without degrading the spatial resolution. Results: For the uptake-curve reconstruction experiment, there was a high correlation between uptake curves reconstructed from fully sampled data by Fourier transform and from undersampled data by RICS, indicating high similarity between them. The mean Pearson correlation coefficients for RICS with the ME/MC approach and RICS with the average approach were 0.977Ϯ 0.023 and 0.953Ϯ 0.031, respectively. The comparisons of final reconstruction results between RICS with the average approach and RICS with the ME/MC approach suggested that the latter was superior to the former in reducing motion related effects. For the in vitro experiment, compared to the fully sampled method, RICS improved the temporal resolution by an acceleration factor of 10 without degrading the spatial resolution. Conclusions: The preliminary study demonstrates the feasibility of RICS for faithfully reconstructing uptake curves and improving temporal resolution of breast DCE-MRI without degrading the spatial resolution.

Purpose To determine the relationship between calcified cortex and perfusion status of white matter and seizure severity in patients with Sturge-Weber Syndrome (SWS), a sporadic neuro-cutaneous disorder characterized by a leptomeningeal angioma, progressive brain ischemia and a high incidence of seizures, using Susceptibility Weighted Imaging (SWI) and Dynamic Susceptibility Contrast-enhanced Perfusion Weighted Imaging (DSC-PWI). Materials and Methods Fifteen children (ages: 0.9-10 years) with unilateral SWS prospectively underwent MR imaging. The degree of cortical calcification was assessed using SWI while perfusion status was quantified using DSC-PWI images (asymmetries of various perfusion parameters). Comparisons between calcification, perfusion status and seizure variables were performed. Results Patients with severely calcified cortex demonstrated significantly lower perfusion in the ipsilateral white matter (mean asymmetry: −0.52±0.22) as compared to patients with only mildly calcified cortex or no calcification (mean asymmetry: 0.08±0.25). Patients with severely calcified cortex also suffered from a higher seizure burden (a composite measure of seizure frequency and epilepsy duration; p=0.01) and a trend for earlier seizure onset and longer epilepsy duration. Conclusion Severe calcification in the affected hemisphere is related to severely decreased perfusion in underlying white matter and is associated with more severe epilepsy in SWS patients.

Background and Purpose Low brain tissue perfusion due to abnormal venous drainage is thought to be a central mechanism of brain damage in Sturge-Weber syndrome (SWS). In the present study, high-resolution perfusion-weighted imaging (HR-PWI) was used to quantify white matter perfusion abnormalities and correlate these with brain atrophy and clinical variables. Materials and Methods Fourteen children (age: 0.8–10.0 years) with unilateral SWS underwent MRI examinations, including HR-PWI. Relative cerebral blood volume (rCBV), cerebral blood flow (rCBF) and mean transit time (MTT) in the affected white matter (WM) and in contralateral homotopic WM were measured. Asymmetry index (AI) for each perfusion parameter was correlated with age, brain atrophy, motor and seizure variables as well as IQ. Results Increased perfusion was seen in the affected hemisphere in 5 children and decreased perfusion in 9. Brain atrophy was more severe in the low-perfusion group (p=0.01) and was related to both CBF-AI and CBV-AI (r = −0.69, p = 0.007; r = −0.64, p = 0.014, respectively). Older children had lower CBV values on the affected side (r = −0.62, p = 0.02). Longer duration of epilepsy was related to lower CBF (more negative CBF-AI, r=−0.58, p=0.03) and low CBV (r=−0.55, p=0.04) on the affected side. Lower perfusion was associated with more frequent seizures (rCBF-AI: r=−0.56, p=0.04; rCBV-AI: r=−0.63, p=0.02). Conclusion Increased perfusion in the affected cerebral WM may indicate an early stage of SWS without severe brain atrophy. Decreased perfusion is associated with frequent seizures, long duration of epilepsy and brain atrophy.

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