Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.
Magn Reson Med. 2010 Mar;63(3):822-7. doi: 10.1002/mrm.22196.
A method was developed for quantitative sodium MRI of the mouse prostate at 9.4 T. A small loop-gap radiofrequency coil was constructed and dual-tuned to both the proton and sodium frequencies. The location and boundary of the mouse prostate were localized using high-resolution T(2)-weighted proton images, and sodium images were acquired with 1mm isotropic resolution using a short echo time (0.6 ms) and a long pulse repetition time (300 ms) for sodium density weighting with minimal T(1) and T(2) contrast. Sodium concentration in the prostate was estimated by comparing pixel intensities within the prostate to the pixel intensities in a pair of reference vials with known sodium concentrations, and a radiofrequency field inhomogeneity correction was performed based on field maps of a homogeneous phantom. In a group of five healthy, 5-month-old BALB/c mice, the average sodium concentration within their prostates was measured to be 173 +/- 38 mM. Muscle tissue and bladder were also clearly visible in the sodium images, and their sodium concentrations were estimated to be 40 +/- 15 mM and 210 +/- 72 mM, respectively.
一种在 9.4T 下对小鼠前列腺进行定量钠 MRI 的方法。构建了一个小的环形缝隙射频线圈，并对质子和钠频率进行双调谐。使用高分辨率 T2 加权质子图像定位和确定小鼠前列腺的位置和边界，并使用短回波时间（0.6ms）和长脉冲重复时间（300ms）以最小的 T1 和 T2 对比获得钠密度加权的 1mm 各向同性分辨率的钠图像。通过将前列腺内的像素强度与具有已知钠浓度的一对参考小瓶内的像素强度进行比较，来估计前列腺中的钠浓度，并基于均匀体的磁场图进行射频场不均匀性校正。在一组五只健康的 5 个月大的 BALB/c 小鼠中，测量其前列腺内的平均钠浓度为 173 ± 38mM。钠图像中还可以清楚地看到肌肉组织和膀胱，它们的钠浓度分别估计为 40 ± 15mM 和 210 ± 72mM。
