title: Novel magnetic resonance imaging contrasts for monitoring response to gene therapy in rat glioma.
abstract: Magnetic resonance imaging relaxation times, T(1rho) and Carr-Purcell T(2) (CP-T(2)), were measured in a glioma herpes simplex virus-thymidine kinase gene therapy model. In treated tumors with >50% cell death by histology, T(1rho) and CP-T(2) measured with short spacing (tau(CP)) between centers of adiabatic refocusing pulses showed similar enhanced sensitivity to cytotoxic cell damage over CP-T(2) measured with long tau(CP) (long-tau(CP) T(2): 54.3 +/- 0.7 and 55.4 +/- 1.2 ms, P = 0.30; short-tau(CP) T(2): 61.3 +/- 1.0 and 64.2 +/- 1.1 ms, P < 0.05 before and day 2 of treatment, respectively). Without treatment, long-tau(CP) T(2) provided the most pronounced contrast between tumor and normal cerebral tissue. These data demonstrate that endogenous T(2) contrast can be modulated and extended in a manner likely to be clinically important.
authors: Department of Biomedical NMR and National Bio NMR Facility, A. I. Virtanen Institute for Molecular Sciences, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland. grohn@messi.uku.fi
authors: Olli H J
authors: OH
authors: Gröhn
authors: Piia K
authors: PK
authors: Valonen
authors: Kimmo K
authors: KK
authors: Lehtimäki
authors: Tuula H
authors: TH
authors: Väisänen
authors: Mikko I
authors: MI
authors: Kettunen
authors: Seppo
authors: S
authors: Ylä-Herttuala
authors: Risto A
authors: RA
authors: Kauppinen
authors: Michael
authors: M
authors: Garwood
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy*; D005260:Female; D015774:Ganciclovir / Q000494:pharmacology; D015316:Genetic Therapy; D005910:Glioma / Q000235:genetics / Q000473:pathology* / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051381:Rats; D012680:Sensitivity and Specificity; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D016896:Treatment Outcome
chemical_list: D013937:Thymidine Kinase; D015774:Ganciclovir