[A comparison between GE and SE sequences in MRT after the i.v. application of superparamagnetic iron particles in the assessment of experimentally induced soft-tissue osteosarcomas].
OBJECTIVE
An MRI study on experimentally induced osteosarcomas of the peripheral soft-tissues in nude rats was conducted, comparing SE and GE sequences after i.v. application of superparamagnetic iron oxides with regard to contrast and image quality.


METHODS
40 nude rats with an osteosarcoma in the right hind leg and 7 tumour-free animals were measured without, one and 48 hours after i.v.-injection of the contrast medium. 4 SE and 3 GE sequences with different parameters and slice orientation were applied. The contrast medium consisted of Fe3O4 particles with a core diameter of 6-8 nm and a coating material of polyethylene glycol (PEG). The laboratory animals were divided into 5 groups of 7-12 animals each. The rats of the first 4 groups were given a contrast-medium dosage of 100, 150, 200 and 250 mumol Fe/kg body weight, respectively. The animals of the fifth group were tumour-free and served as controls.


RESULTS
The minimum dosage for detection of Fe3O4-containing PEG magnetites, one hour after application, was established at 100-150 mumol Fe/kg body weight. The higher the dosage of the contrast medium, the more signal alterations could be measured. The GE sequences were more sensitive than SE sequences. One GE sequence with the parameters TR 90 ms, TE 13 ms, FL 8 degrees turned out to be highly sensitive.


CONCLUSIONS
Superparamagnetic iron oxides induce signal alterations in tumours of the peripheral soft tissue. GE sequences proved to be more sensitive than SE sequences.
Axmann
C
C
Klinik für Diagnostische Radiologie und Neuroradiologie, Zentralklinikum Augsburg.
Bohndorf
K
K
Gellissen
J
J
Prescher
A
A
Lodemann
M
M
D000818:Animals; D001859:Bone Neoplasms / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D052203:Ferrosoferric Oxide; D007275:Injections, Intravenous; D007501:Iron / Q000008:administration & dosage; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D009368:Neoplasm Transplantation; D012516:Osteosarcoma / Q000175:diagnosis*; D010087:Oxides / Q000008:administration & dosage; D010316:Particle Size; D014677:Pharmaceutical Vehicles; D011092:Polyethylene Glycols; D051381:Rats; D011923:Rats, Nude; D012680:Sensitivity and Specificity; D012983:Soft Tissue Neoplasms / Q000175:diagnosis*; D013997:Time Factors
D003287:Contrast Media; D010087:Oxides; D014677:Pharmaceutical Vehicles; D011092:Polyethylene Glycols; D007501:Iron; D052203:Ferrosoferric Oxide