title: In vitro assessment of factors affecting the apparent diffusion coefficient of Jurkat cells using bio-phantoms.
abstract: It is well known that many tumor tissues show lower apparent diffusion coefficient (ADC) values, and that several factors are involved in the reduction of ADC values. The aim of this study was to clarify how much each factor contributes to decreases in ADC values. We investigate the roles of cell density, extracellular space, intracellular factors, apoptosis and necrosis in ADC values using bio-phantoms. The ADC values of bio-phantoms, in which Jurkat cells were encapsulated by gellan gum, were measured by a 1.5-Tesla magnetic resonance imaging device with constant diffusion time of 30sec. Heating at 42℃ was used to induce apoptosis while heating at 48℃ was used to induce necrosis. Cell death after heating was evaluated by flow cytometric analysis and electron microscopy. The ADC values of bio-phantoms including non-heated cells decreased linearly with increases in cell density, and showed a steep decline when the distance between cells became less than 3μm. The analysis of ADC values of cells after destruction of cellular structures by sonication suggested that approximately two-thirds of the ADC values of cells originate from their cellular structures. The ADC values of bio-phantoms including necrotic cells increased while those including apoptotic cells decreased. This study quantitatively clarified the role of the cellular factors and the extracellular space in determining the ADC values produced by tumor cells. The intermediate diffusion time of 30msec might be optimal to distinguish between apoptosis and necrosis.
authors.affiliation: Department of Oral and Maxillofacial Radiology Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Katashima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kuroda
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ashida
authors.forename: Takanori
authors.initials: T
authors.lastname: Sasaki
authors.forename: Takehito
authors.initials: T
authors.lastname: Taguchi
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Jun
authors.initials: J
authors.lastname: Murakami
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Yanagi
authors.forename: Miki
authors.initials: M
authors.lastname: Hisatomi
authors.forename: Marina
authors.initials: M
authors.lastname: Hara
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kato
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ohmura
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Susumu
authors.initials: S
authors.lastname: Kanazawa
authors.forename: Sosuke
authors.initials: S
authors.lastname: Harada
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takemoto
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Ohno
authors.forename: Seiichi
authors.initials: S
authors.lastname: Mimura
authors.forename: Junichi
authors.initials: J
authors.lastname: Asaumi
mesh_terms: D001692:Biological Transport / Q000502:physiology; D002452:Cell Count; D002478:Cells, Cultured; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005110:Extracellular Space / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D019169:Jurkat Cells / Q000378:metabolism* / Q000473:pathology; D019047:Phantoms, Imaging; D013997:Time Factors