title: A new phantom using polyethylene glycol as an apparent diffusion coefficient standard for MR imaging.
abstract: In recent years, magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has seen wide clinical use, such as for early detection of cerebrovascular diseases and whole body screening for tumors. The apparent diffusion coefficient (ADC) standard phantom, which mimics the ADC values of several lesions in the body, is indispensable for the development of new pulse sequences for DWI, such as diffusion-weighted whole-body imaging with background body-signal suppression (DWIBS). However, information on the ADC values of the previously reported ADC standard phantoms is limited, because these phantoms were made using only a few different materials at a limited range of concentrations, and the ADC values were measured only at certain temperatures. It has been considered difficult, if not impossible, to create a phantom that provides arbitrary ADC values, because it is difficult to calculate the concentrations of the materials and the temperature at ADC measurement. In this study, we used polyethylene glycol (PEG) as a phantom material, and developed an empirical formula to calculate the PEG concentration at any measurement temperature to obtain arbitrary ADC values of the phantom. DWI images of phantoms made using seven different PEG concentrations were taken under heating from 17 to 46 degrees C at 1 degrees C intervals. Using ADC values calculated from these DWI images, we developed two empirical formulas: i) an empirical formula to calculate the ADC values of phantoms made using any PEG concentration at any measurement temperature; and ii) an empirical formula to calculate PEG concentrations to obtain arbitrary ADC values at any measurement temperature. We inspected the accuracy of these empirical formulas by newly made PEG phantoms. A comparison between the ADC values calculated with the empirical formulas and the measured ADC values confirmed the high accuracy of these formulas. PEG phantoms are safe, inexpensive and easy to make, compared with the previously reported ADC standard phantoms. Our empirical formulas enable us to calculate PEG concentrations that provide arbitrary ADC values at any measurement temperature. The empirical formulas could be used within a range of ADC values from 0.37x10(-3) to 3.67x10(-3) mm(2)/s, PEG concentrations from 0 to 120 mM, and measurement temperatures from 18 to 45 degrees C. Using these formulas, it would be possible to make standard phantoms that mimic the ADC values of any clinical lesions. The PEG phantom might thus be an excellent new ADC standard phantom for MRI with DWI.
authors.affiliation: Faculty of Health Sciences, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Matsuya
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kuroda
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kato
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Junichi
authors.initials: J
authors.lastname: Asaumi
authors.forename: Jun
authors.initials: J
authors.lastname: Murakami
authors.forename: Kazunori
authors.initials: K
authors.lastname: Katashima
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ashida
authors.forename: Takanori
authors.initials: T
authors.lastname: Sasaki
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sei
authors.forename: Kengo
authors.initials: K
authors.lastname: Himei
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Katsui
authors.forename: Norihisa
authors.initials: N
authors.lastname: Katayama
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takemoto
authors.forename: Susumu
authors.initials: S
authors.lastname: Kanazawa
authors.forename: Seiichi
authors.initials: S
authors.lastname: Mimura
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Oono
authors.forename: Takuichi
authors.initials: T
authors.lastname: Kitayama
authors.forename: Seiji
authors.initials: S
authors.lastname: Tahara
authors.forename: Keiji
authors.initials: K
authors.lastname: Inamura
mesh_terms: D001932:Brain Neoplasms / Q000175:diagnosis*; D002544:Cerebral Infarction / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation* / Q000592:standards; D036262:Empirical Research; D006801:Humans; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D011092:Polyethylene Glycols; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D011092:Polyethylene Glycols