title: [Investigation of radiofrequency heating for a closed conducting loop formed in a part of the patient's body in 1.5 Tesla magnetic resonance (MR) imaging and 3.0 Tesla MR imaging-measurement of temperature by use of human body-equivalent phantom].
abstract: Thermal injuries have been sometimes reported due to a closed conducting loop formed in a part of the patient's body during magnetic resonance imaging (MRI). In recent years, 3.0 T-MRI scanner has been widely used. However, it is considered that the specific absorption rate (SAR) of 3.0 T-MRI can affect the heat of the loop because its own SAR becomes approximately 4 times as much as that of the1.5 T-MRI scanner. With this, the change in temperature was measured with human body-equivalent loop phantom in both 1.5 T-MRI and 3.0 T-MRI. In the two scanners, the temperature during 20 min of scanning time was measured with three types of sequences such as field echo (FE), spin echo (SE), and turbo SE (TSE) set up with the same scanning condition. It was found from the result that rise in temperature depended on SAR of the scanning condition irrespective of static magnetic field intensity and any pulse sequences. Furthermore, the increase of SAR and rise in temperature were not only in proportion to each other but also were indicated to have good correlation. However, even low SAR can occasionally induce serious thermal injuries. It was found from result that we had to attempt not to form a closed conducting loop with in a part of the patient's body during MRI.
authors.affiliation: Department of Radiologic Technology, Osaka City University Hospital.
authors.forename: Masaru
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Mitsuji
authors.initials: M
authors.lastname: Higashida
authors.forename: Sadahiro
authors.initials: S
authors.lastname: Kudo
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ideta
authors.forename: Masami
authors.initials: M
authors.lastname: Nakazawa
mesh_terms: D002056:Burns / Q000209:etiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects* / Q000379:methods*; D019047:Phantoms, Imaging; D013696:Temperature