title: In vitro experimental study of the relationship between the apparent diffusion coefficient and changes in cellularity and cell morphology.
abstract: Diffusion-weighted magnetic resonance imaging (MRI) is frequently used clinically, and is available for the whole-body screening for tumors. The exact mechanism by which the apparent diffusion coefficient (ADC) value decreases in tumorous tissue remains unclear, although various theories have been proposed, including intracellular and extracellular factor theories. It is impossible to distinguish each factor in the intracellular and extracellular spaces as the source of MR signal generation by means of conventional comparison between MR images and pathological specimens. Other factors which have been reported to affect ADC include cellularity and cellular edema of human tissues, and temperature of phantoms at the time of measurement. We employed a new technique that enables cellular MR imaging using a newly developed bio-phantom containing a living culture tumor cell line, Jurkat-N1. We investigated possible reasons for observed decreases in ADC values for tumors, and we considered the contribution of both the intracellular and extracellular space to such a decrease. The ADC values of the bio-phantom increased with increasing heat exposure from 27 to 45 degrees C. ADC values also increased after the destruction by sonication of tumor cell membranes. ADC values decreased as cellularity increased in the bio-phantom. ADC values decreased due to cellular edema caused by a low salt concentration in the bio-phantom. Changes in pressure in the bio-phantom had no effect on the observed ADC values. We calculated both the intracellular ADC and extracellular ADC values using the ADC values, cellularity, and cellular volume of Jurkat-N1 cells in the bio-phantom. The extracellular ADC values in the bio-phantom were estimated to be lower than the ADC value of distilled water. These results indicate that not only intracellular ADC values, but also extracellular ADC values contribute to the determination of the ADC values of bio-phantoms. This is the first report to have examined the contribution of intracellular and extracellular space on the ADC values of bio-phantoms containing cultured tumor cells.
authors.affiliation: Faculty of Health Sciences, Graduate School of Health Sciences, Department of Radiology, Okayama University Hospital, Okayama University, Okayama 700-8558, Japan.
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kuroda
authors.forename: Ryohei
authors.initials: R
authors.lastname: Matsuya
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kato
authors.forename: Koichi
authors.initials: K
authors.lastname: Shibuya
authors.forename: Masataka
authors.initials: M
authors.lastname: Oita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawabe
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: 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: D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D019169:Jurkat Cells; D009369:Neoplasms / Q000473:pathology*; D019047:Phantoms, Imaging; D013696:Temperature