Bansal N, Seshan V
Department of Radiology, Mary Nell and Ralph B. Rogers Magnetic Resonance Center, University of Texas Southwestern Medical Center at Dallas 75235-9085, USA.
J Magn Reson Imaging. 1995 Nov-Dec;5(6):761-7. doi: 10.1002/jmri.1880050624.
Low signal-to-noise ratio (SNR) has been the main obstacle to multiple quantum-filtered 23Na imaging becoming an important technique for biologic and clinical applications. Through computer simulations and phantom experiments, we show that the SNR in 23Na imaging can be substantially improved by weighted signal averaging. Three-dimensional single quantum and triple quantum (TQ)-filtered 23Na images of an externalized rabbit kidney were collected with this technique. The TQ-filtered image did not show any signal when the animal was alive. However, upon sacrificing the animal, the renal cortex became clearly visible without any significant increase in signal from the medullary region. This increase in TQ-filtered signal in the renal cortex may be caused by an increased concentration of intracellular Na+ in the large intracellular space present herein, compared with the medulla. To our knowledge, this study represents the first example of three-dimensional TQ-filtered 23Na image of a biological sample.
低信噪比（SNR）一直是多量子滤波23Na成像成为生物学和临床应用重要技术的主要障碍。通过计算机模拟和体模实验，我们表明加权信号平均可大幅提高23Na成像中的信噪比。利用该技术采集了外置兔肾的三维单量子和三量子（TQ）滤波23Na图像。动物存活时，TQ滤波图像未显示任何信号。然而，处死动物后，肾皮质清晰可见，髓质区域信号无明显增加。与髓质相比，此处大细胞内空间中细胞内Na+浓度增加可能导致肾皮质中TQ滤波信号增加。据我们所知，本研究是生物样本三维TQ滤波23Na图像的首个实例。
