Dataset Information

Stimulated echo based mapping (STEM) of T1 , T2 , and apparent diffusion coefficient: validation and protocol optimization.

ABSTRACT: PURPOSE:To present a stimulated-echo based mapping (STEM) approach for simultaneous T1 , T2 , and ADC mapping. METHODS:Diffusion-weighted stimulated-echo images with various combinations of mixing time (TM), TE, and b-value were acquired to enable simultaneous mapping of T1 , T2 , and ADC. The proposed STEM method was performed by densely sampling the TM-TE-b space in a phantom and in brain and prostate of healthy volunteers. T1 , T2 , and ADC from STEM were compared to reference mapping methods. Additionally, protocol optimization was performed to enable rapid STEM acquisition within 2?min by sparsely sampling the TM-TE-b space. The T1 , T2 , and ADC measurements from rapid acquisitions were compared to the densely sampled STEM for evaluation. Finally, a patient with biopsy-proven high-risk prostate cancer was imaged to demonstrate the ability of STEM to differentiate cancer and healthy tissues. RESULTS:Relative to the reference measurements, densely sampled STEM provided accurate quantitative T1 , T2 , and ADC mapping in phantoms (R2 ?=?0.999, slope between 0.97-1.03), as well as in brain and prostate. Further, the T1 , T2 , and ADC measurements from the optimized rapid STEM acquisitions agreed closely with densely sampled STEM. Finally, STEM showed decreased T2 and ADC in prostate cancer compared to healthy prostate tissue. CONCLUSION:STEM provides accurate simultaneous mapping of T1 , T2 , and ADC. This method may enable rapid and accurate multi-parametric tissue characterization for clinical and research applications.

SUBMITTER: Zhang Y

PROVIDER: S-EPMC6258304 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Publications

Stimulated echo based mapping (STEM) of T<sub>1</sub> , T<sub>2</sub> , and apparent diffusion coefficient: validation and protocol optimization.

Zhang Yuxin Y Wells Shane A SA Hernando Diego D

Magnetic resonance in medicine 20180719 1

<h4>Purpose</h4>To present a stimulated-echo based mapping (STEM) approach for simultaneous T<sub>1</sub> , T<sub>2</sub> , and ADC mapping.<h4>Methods</h4>Diffusion-weighted stimulated-echo images with various combinations of mixing time (TM), TE, and b-value were acquired to enable simultaneous mapping of T<sub>1</sub> , T<sub>2</sub> , and ADC. The proposed STEM method was performed by densely sampling the TM-TE-b space in a phantom and in brain and prostate of healthy volunteers. T<sub>1</su ...[more]

PMID: 30024051

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Project description:Background and Purpose- In this era of endovascular therapy (EVT) with early, complete recanalization and reperfusion, we have observed an even more rapid apparent diffusion coefficient (ADC) normalization within the acute ischemic lesion compared with the natural history or IV-tPA-treated patient. In this study, we aimed to evaluate the effect of revascularization on ADC evolution within the core lesion in the first 24 hours in acute ischemic stroke patients. Methods- This retrospective study included anterior circulation acute ischemic stroke patients treated with EVT with or without intravenous tPA (IVT) from 2015 to 2017 compared with a consecutive cohort of IVT-only patients treated before 2015. Diffusion-weighted imaging and ADC maps were used to quantify baseline core lesions. Median ADC value change and core reversal were determined at 24 hours. Diffusion-weighted imaging lesion growth was measured at 24 hours and 5 days. Good clinical outcome was defined as modified Rankin Scale score of 0 to 2 at 90 days. Results- Twenty-five patients (50%) received IVT while the other 25 patients received EVT (50%) with or without IVT. Between these patient groups, there were no differences in age, sex, baseline National Institutes of Health Stroke Scale, interhospital transfer, or IVT rates. Thirty-two patients (64%) revascularized with 69% receiving EVT. There was a significant increase in median ADC value of the core lesion at 24 hours in patients who revascularized compared with further ADC reduction in nonrevascularization patients. Revascularization patients had a significantly higher rate of good clinical outcome at 90 days, 63% versus 9% (P=0.003). Core reversal at 24 hours was significantly higher in revascularization patients, 69% versus 22% (P=0.002). Conclusions- ADC evolution in acute ischemic stroke patients with early, complete revascularization, now more commonly seen with EVT, is strikingly different from our historical understanding. The early ADC normalization we have observed in this setting may include a component of secondary injury and serve as a potential imaging biomarker for the development of future adjunctive therapies. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT00009243.

Dataset Information

Stimulated echo based mapping (STEM) of T1 , T2 , and apparent diffusion coefficient: validation and protocol optimization.

Publications

Stimulated echo based mapping (STEM) of T<sub>1</sub> , T<sub>2</sub> , and apparent diffusion coefficient: validation and protocol optimization.

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