Detection of Lesions in Mesial Temporal Lobe Epilepsy by Using MR Fingerprinting

et al. 2019

Ann Clin Transl Neurol

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Objective Mesial temporal lobe epilepsy (MTLE) is a network disorder. We aimed to quantify the white matter alterations in the temporal lobe of MTLE patients with hippocampal sclerosis (MTLE‐HS) by using magnetic resonance fingerprinting (MRF), a novel imaging technique, which allows simultaneous measurements of multiple parameters with a single acquisition. Methods We consecutively recruited 27 unilateral MTLE‐HS patients and 22 healthy controls. Measurements including T1, T2, and PD values in the temporopolar white matter and temporal stem were recorded and analyzed. Results We found increased T2 value in both sides, and increased T1 value in the ipsilateral temporopolar white matter of MTLE‐HS patients, as compared with healthy controls. The T1 and T2 values were higher in the ipsilateral than the contralateral side. In the temporal stem, increased T1 and T2 values in the ipsilateral side of the MTLE‐HS patients were also observed. Only increased T2 values were observed in the contralateral temporal stem. No significant differences in PD values were observed in either the temporopolar white matter or temporal stem of the MTLE‐HS patients. Correlation analysis revealed that T1 and T2 values in the ipsilateral temporopolar white matter were negatively correlated with the age at epilepsy onset. Interpretation By using MRF, we were able to assess the alterations of T1 and T2 in the temporal lobe white matter of MTLE‐HS patients. MRF could be a promising imaging technique in identifying mild changes in MTLE patients, which might optimize the pre‐surgical evaluation and therapeutic interventions in these patients.

“…and D.W.). The inclusion and exclusion criteria were as previously described . The diagnosis of HS was in accordance with previously described method .…”

Section: Methodsmentioning

confidence: 99%

Magnetic resonance fingerprinting of temporal lobe white matter in mesial temporal lobe epilepsy

Wang

et al. 2019

Ann Clin Transl Neurol

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“…By template matching these "fingerprints" to a pre-calculated dictionary that includes entries of all possible combinations of quantitative parameters such as T 1 and T 2 , the parameters for the fingerprints can be retrieved from the best-matched entry in the dictionary. MRF has been investigated for its potential as a diagnostic tool for some diseases such as prostate cancer, 2 brain tumors, 3 and epilepsy, 4 which explains the high level of interest and suggests the potential for this technique.…”

Section: Introductionmentioning

confidence: 99%

Fast 3D brain MR fingerprinting based on multi‐axis spiral projection trajectory

Magnetic Resonance in Med

Liao

et al. 2019

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Purpose:To develop a fast, sub-millimeter 3D magnetic resonance fingerprinting (MRF) technique for whole-brain quantitative scans. Methods: An acquisition trajectory based on multi-axis spiral projection imaging (maSPI) was implemented for 3D MRF with steady-state precession and slab excitation. By appropriately assigning the in-plane and through-plane rotations of spiral interleaves in a novel acquisition scheme, an maSPI-based acquisition was implemented, and the total acquisition time was reduced by up to a factor of 8 compared to stack-of-spiral (SOS)-based acquisition. A sliding-window method was also used to further reduce the required number of time points for a faster acquisition. The experiments were conducted both on a phantom and in vivo. Results:The results from the phantom measurements with the proposed and gold standard methods were consistent with a good linear correlation and an R 2 value approaching 0.99. The in vivo experiments achieved whole-brain parametric maps with isotropic resolutions of 1 mm and 0.8 mm in 5.0 and 6.0 min, respectively, with potential for further acceleration. An in vivo experiment with intentionally moving subjects demonstrated that the maSPI scheme largely outperforms the SOS scheme in terms of robustness to head motion. Conclusion: 3D MRF with an maSPI acquisition scheme enables fast and robust scans for high-resolution parametric mapping. K E Y W O R D S 3D, MR fingerprinting, spiral projection trajectory 290 | CAO et Al. ORCID Congyu Liaohttps://orcid.org/0000-0003-2270-276X

“…Different tissue properties such as T 1 , T 2 ,

T_{2}^{*}

, and PD are incorporated into the signal evolutions induced by changing the flip angle, TR, and TE . In addition, MRF has shown its potential clinical applications in the human abdomen and brain . However, challenges remain in using MRF to quantify tissues containing ultrashort T 2 components.…”

Section: Introductionmentioning

confidence: 99%

“…21 In addition, MRF has shown its potential clinical applications in the human abdomen and brain. 22,23 However, challenges remain in using MRF to quantify tissues containing ultrashort T 2 components. First, since the original MRF method has a minimum echo time of several milliseconds, ultrashort T 2 /T * 2 tissues are barely detected.…”

Section: Introductionmentioning

confidence: 99%

Ultrashort echo time magnetic resonance fingerprinting (UTE‐MRF) for simultaneous quantification of long and ultrashort T₂ tissues

Magnetic Resonance in Med

et al. 2019

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Purpose To demonstrate an ultrashort echo time magnetic resonance fingerprinting (UTE‐MRF) method that allows quantifying relaxation times for muscle and bone in the musculoskeletal system and generating bone enhanced images that mimic CT scans. Methods A fast imaging steady‐state free precession MRF sequence with half pulse excitation and half projection readout was designed to sample fast T2 decay signals. Varying echo time (TE) of a sinusoidal pattern was applied to enhance sensitivity for tissues with short and ultrashort T2 values. The performance of UTE‐MRF was evaluated via simulations, phantom, and in vivo experiments. Results A minimal TE of 0.05 ms was achieved. Simulations indicated the sinusoidal TE sampling increased T2 quantification accuracy in the cortical bone and tendon but had little impact on long T2 muscle quantifications. For the rubber phantom, the averaged relaxometries from UTE‐MRF (T1 = 162 ms and T2 = 1.07 ms) compared well with the gold standard (T1 = 190 ms and T2∗ = 1.03 ms). For the long T2 agarose phantom, the linear regression slope between UTE‐MRF and gold standard was 1.07 (R2 = 0.991) for T1 and 1.04 (R2 = 0.994) for T2. In vivo experiments showed the detection of the cortical bone (averaged T2 = 1.0 ms) and Achilles tendon (averaged T2 = 15 ms). Scalp structures from the bone enhanced image show high similarity with CT. Conclusion The UTE‐MRF with sinusoidal TEs can simultaneously quantify T1, T2, proton density, and B0 in long, short, even ultrashort T2 musculoskeletal structures. Bone enhanced images can be achieved in the brain with UTE‐MRF.