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The initial results of in vivo 23Na magnetic resonance imaging (MRI) of the human torso at 3-Tesla using an 8-channel dual tuned 23Na and 1H transmit/receive coil for various body applications are presented. We are able to obtain 23Na images of the human torso with 0.3 cm spatial resolution and ∼ 20 SNR in ∼15 min. These images were acquired with imaging parameters optimized under specific absorption rate limit for human scans. Because a trans-membrane sodium gradient is critical for cell survival, the ability to perform 23Na MRI of the torso in clinical settings would be useful to noninvasively detect and diagnose a number of diseases of the liver, gallbladder, pancreas, kidney, spleen and other body organs.

An MR technique has been developed to administer controlled radiofrequency (RF) hyperthermia (HT) to treat sc-implanted tumors using an MR scanner and its components. The method uses the 1H chemical shift of TmDOTA− to monitor tumor temeprature non-invasively. The desired HT temeprature is achieved and maintained using a feedback loop mechanism that uses a proportional-derivative (PD) controller. The RF HT techqinue has been able to heat the tumor from 33 to 45 °C in ∼ 10 min and was able to mainatain the tumor temeprature within ±0.2 °C of the target temperature. Simultaneous monitoring of the metabolic changes with RF HT using multinuclear MRS techniques showed a significant increase in the [Nai]+ as measured by TQF 23Na MRS and a significant decrease in cellular bioenergetics and pH as measured by 31P MRS.