Specific absorption rate intersubject variability in 7T parallel transmit MRI of the head

Specific Absorption Rate Analysis of Heterogeneous Head Models with EEG Electrodes/Leads at 7T MRI

Specific absorption rate studies of the parallel transmission of inner-volume excitations at 7T.

PURPOSE To investigate the behavior of whole-head and local specific absorption rate (SAR) as a function of trajectory acceleration factor and target excitation pattern due to the parallel transmission (pTX) of spatially tailored excitations at 7T. MATERIALS AND METHODS Finite-difference time domain (FDTD) simulations in a multitissue head model were used to obtain B(1) (+) and electric field...

Experimental Temperature and Specific Absorption Rate Mapping Using MRI in a Transmit-receive Head Coil at 3.0T

Introduction: MRI-based temperature mapping techniques have been applied to detect the temperature changes (∆T ) for a variety of applications, including during the thermoablation of tumors [1], and in verifying minimal temperature increment induced by EEG electrodes and/or its wires during MRI [2]. Although numerical calculations have been used to predict SAR distributions and resulting temper...

Finite Difference Time Domain (FDTD) Simulation of Receive-Only Array Inserts for 7T Transmit-Only Head Coil: Influence on Spin Excitation and Specific Absorption Rate (SAR)

During MR procedures majority of the radiofrequency (RF) power transmitted for imaging or spectroscopy is transformed into heat within the patient’s tissue as a result of resistive losses. In this work we evaluate the effect of a wide variety of receive-only insert geometry including cylinders and helmets with different trace widths on spin excitation field and SAR of a 7T TEM transmit coil.

Specific Absorption Rate (SAR) in the head of Tablet user's

Wireless communication devices such as tablets are increasing and developing rapidly. The effects of the electromagnetic (EM) waves in the human body from the wireless communication devices have been paid attention. It is well known that the absorption of electromagnetic waves on the human head for a certain period of time may lead to health problems such as headaches, or even worse, significan...