Noise Analysis for Multi-slice Radio Frequency Current Density Imaging

Abstract

Radio frequency current density imaging (RF-CDI) is an imaging technique that measures current density distribution at the Larmor frequency utilizing magnetic resonance imaging (MRI). The multi-slice RF-CDI sequence has extended the ability of RF-CDI to image multiple slices and thus has enhanced its capacity for biomedical applications. In this paper, the influence of MRI random noise on the sensitivity of multi-slice RF-CDI measurement is studied. The formula of current noise is derived, which is verified by both simulation and phantom experiments. A 3-D finite-difference time-domain (FDTD) model is employed to compute the electromagnetic fields in the simulation. T. P. DeMonte is with Field

Noise Analysis for Multi-slice Radio Frequency Current Density Imaging

“…Mean and standard deviation of current density were estimated for RF-CDI experiment with mean current density around 97 A/m 2 [5]. The estimated standard deviations were much larger compared to the current noise predicted by (8).…”

“…However, unlike LF-CDI and single-slice RF-CDI, multislice RF-CDI does not encode the current density information in MRI phase images directly. Instead, each twist angle due to the magnetic component produced by RF current is calculated from four complex images by arc tangent operation [5]. Therefore, the general form of current density noise needs to be modified and parameters need to be clarified for multi-slice RF-CDI.…”

“…, are acquired to estimate x and the other four are for y[5].x is computed through arc tangent (1 tan ) or arc cotangent Noise Analysis for Multi-slice Radio Frequency Current Density Imaging Dinghui Wang, Tim P. DeMonte, Member, IEEE, Michael L. Joy, Member, IEEE, 4244-0033-3/06/$20.00 ©2006 IEEE.…”

RF Field Visualization of RF Ablation at the Larmor Frequency

“…Potentially, RF current density imaging (RFCDI) [39]–[43] could be used to directly visualize the RF ablating current in the tissue. For a full volumetric vector reconstruction, RFCDI requires all three components of the magnetic field, including the field parallel to B 0 .…”