Nonlinear Reconstruction for MR Spectroscopic Imaging of Human Calf in Diabetes

糖尿病人小牛磁共振波谱成像的非线性重建

• 批准号: 9035985
• 负责人: MICHAEL Albert THOMAS
• 金额: $ 17.95万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9035985
• 关键词: Age; Applications Grants; COSY; Chemicals; Choline; Data; Detection; Development; Diabetes Mellitus; Dimensions; Discrimination; Disease; Effectiveness; Enzymes; Evaluation; Exhibits; Fiber; Four-dimensional; Future; Glucose; Goals; Human; Human Volunteers; Image; Imaging Techniques; Imaging technology; Insulin; Insulin Resistance; Intervention; Investigation; Knee; Lead; Lipids; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Measures; Metabolic; Metabolism; Methodology; Methods; Morphologic artifacts; Muscle; Muscle Fibers; Names; Non-Insulin-Dependent Diabetes Mellitus; Pathogenesis; Patients; Performance; Physiologic pulse; Play; Process; Process Assessment; Reporting; Research; Role; Skeletal Muscle; Slice; Techniques; Testing; Therapeutic Intervention; Time; Triglycerides; Unsaturated Fats; Validation; Work; base; cohort; desaturase; diabetic patient; flexibility; follow-up; glucose disposal; improved; in vivo; indexing; innovation; insulin sensitivity; interest; lipid metabolism; muscle metabolism; new technology; non-diabetic; novel; novel therapeutic intervention; prevent; public health relevance; radio frequency; reconstruction; response; saturated fat; sex; spectroscopic imaging; therapy design; tibialis anterior muscle; tool; uptake

 DESCRIPTION (provided by applicant): There is considerable interest in defining the processes that lead to the increased accumulation of intramyocellular and extramyocellular lipids (IMCL and EMCL) and lipid unsaturation ratios, and determining the relationships of these changes to the development of insulin resistance (IR) and progression to type 2 diabetes (T2D). Thus, development of novel imaging techniques for lipid and metabolite characterization is needed to allow repeated, non-invasive assessment of these processes in vivo. To achieve this goal, the current proposal will develop and pilot test non-linear reconstruction of a novel accelerated multi- gradient/spin-echo based five-dimensional (5D) MR Spectroscopic Imaging (MRSI) data using non-uniform undersampling (NUS) along one spectral and one spatial dimensions. Recently, a 2nd spectral dimension was added to echo-planar-spectroscopic imaging (EPSI) and named echo-planar correlated spectroscopic imaging (EP-COSI). A multi-echo (ME) version of 5D EP-COSI, named ME-EPCOSI, which is capable of acquiring the data faster than EP-COSI will be implemented on a 3T MRI scanner using a 15- channel knee coil. The sequence will be further optimized for achieving better slice refocusing using the adiabatic full passage 1800 radio-frequency (RF) pulses as the adiabatic RF pulses will improve slice selection profile and reduce chemical shift artifacts better than the commonly used Mao RF pulse. This new sequence will enable better discrimination between the unsaturated and saturated lipid groups in skeletal muscle than the conventional MRS techniques and will allow metabolite imaging of multiple muscle groups simultaneously to better understand the specific relationship between IMCL and insulin sensitivity. Two specific goals are proposed: 1) complete the development of the NUS 5D ME-EP-COSI technology to allow simultaneous determination of IMCL and EMCL levels and lipid unsaturation indices in three calf muscle groups with differing type1/type 2 fiber and IMCL content in 20 young healthy human volunteers and to compare its performance using conventional 3D MRSI; and 2) utilize this new technology to study 20 patients with T2D and 20 matched non-diabetic, healthy subjects. The proposed studies will test the following two hypotheses: 1) a NUS-based 5D MEEP-COSI technique will be more robust than the fully encoding 5D EPCOSI and MRSI sequences, enabling simultaneous recording of 2D COSY spectra in multiple slices of calf skeletal muscle, 2) relative to healthy controls, patients with T2D will exhibit: a) increased skeletal muscle IMCL and EMCL, and b) reduced choline, IMCL and EMCL lipid unsaturation indices. The proposed multi-dimensional MR spectroscopic imaging is expected to facilitate the development and validation of an important new research tool that will significantly advance research in the mechanisms of the development of IR and T2D and may ultimately serve as a convenient methodology to rapidly and non-invasively assess responses to new therapeutic interventions designed to ameliorate IR and treat T2D by normalizing muscle lipid metabolism.

 描述（由申请人提供）：人们对定义导致肌细胞内和肌细胞外脂质（IMCL 和 EMCL）和脂质不饱和比率积累增加的过程以及确定这些变化与胰岛素抵抗发展的关系非常感兴趣。因此，需要开发用于脂质和代谢物表征的新型成像技术，以实现体内这些过程的重复、非侵入性评估。为了实现这一目标，当前的提案将使用非均匀欠采样 (NUS) 来开发和试点测试基于加速多梯度/自旋回波的五维 (5D) MR 光谱成像 (MRSI) 数据的非线性重建。最近，回波平面光谱成像 (EPSI) 中添加了第二个光谱维度，并命名为回波平面相关光谱成像 (EP-COSI)。 5D EP-COSI 的多回波 (ME) 版本（名为 ME-EPCOSI）能够比 EP-COSI 更快地获取数据，将在使用 15 通道膝部线圈的 3T MRI 扫描仪上实现该序列。使用绝热全通道 1800 射频 (RF) 脉冲进一步优化，以实现更好的切片重新聚焦，因为绝热 RF 脉冲将比常用的更好地改善切片选择轮廓并减少化学位移伪影Mao 射频脉冲。与 MRS 技术相比，这种新序列将能够更好地区分骨骼肌中的不饱和和饱和脂质组，并且允许同时对多个肌肉组进行常规代谢成像，以更好地了解 IMCL 和胰岛素敏感性之间的特定关系。提出的目标是：1) 完成 NUS 5D ME-EP-COSI 技术的开发，以允许同时测定三个不同小腿肌肉群的 IMCL 和 EMCL 水平以及脂质不饱和指数。 2）利用这项新技术研究 20 名 T2D 患者和 20 名匹配的非糖尿病健康受试者。将测试以下两个假设：1）基于 NUS 的 5D MEEP-COSI 技术将比完全编码的 5D EPCOSI 和 MRSI 序列更强大，从而能够同时记录小腿骨骼肌多个切片中的 2D COSY 光谱，2) 相对于健康对照，T2D 患者将表现出：a) 骨骼肌 IMCL 和 EMCL 增加，b) 胆碱、IMCL 和 EMCL 脂质不饱和指数降低。三维 MR 光谱成像有望促进一种重要的新研究工具的开发和验证，该工具将显着推进 IR 和 T2D 发展机制的研究，最终可能成为一种方便的方法，用于快速、非侵入性地评估对旨在通过使肌肉脂质代谢正常化来改善 IR 和治疗 T2D 的新治疗干预措施的反应。