Dagher A P, Aletras A, Choyke P, Balaban R S
Diagnostic Radiology Department, National Institutes of Health, Bethesda, Maryland 20892, USA.
J Magn Reson Imaging. 2000 Nov;12(5):745-8. doi: 10.1002/1522-2586(200011)12:5<745::aid-jmri12>3.0.co;2-h.
The purpose of this study was to screen for slow proton chemical exchange between water and kidney metabolites using a standard clinical 1.5-T scanner. Imaging was performed using a fast spin-echo sequence with a magnetization transfer (MT) preparation pulse train. Off-resonance saturation ranging from +/-50 to +/-1000 Hz was used on urea and urine phantoms and normal human subjects imaged through the kidneys. The positive frequency was used as the control for each frequency pair. Results of frequency sweeps show an asymmetric MT effect peaking at approximately 100 Hz ( thick similar1 ppm) for urea, urine, and renal parenchyma. Varying differences (5%-25%) occurred with different human subjects. Few differences were observed from phantom water or subject muscle tissue. Chemical exchange is detectable in the kidney near 1 ppm at 1.5 T, attributable to urea. This technique was used to produce in vivo distribution maps of this metabolite in vivo.
本研究的目的是使用标准临床1.5-T扫描仪筛选水与肾脏代谢物之间的慢质子化学交换。成像采用具有磁化传递（MT）准备脉冲序列的快速自旋回波序列。对尿素和尿液模体以及通过肾脏成像的正常人体受试者使用了范围为+/-50至+/-1000 Hz的失谐饱和。每个频率对均以正频率作为对照。频率扫描结果显示，尿素、尿液和肾实质的不对称MT效应在约100 Hz（约1 ppm）处达到峰值。不同人体受试者之间存在不同差异（5%-25%）。在模体水或受试者肌肉组织中观察到的差异很少。在1.5 T时，肾脏中可检测到接近1 ppm的化学交换，这归因于尿素。该技术用于生成该代谢物在体内的分布图。
