D. Lanens et al., COMPLEMENTARY USE OF T2-WEIGHTED AND POSTCONTRAST T1-WEIGHTED NMR IMAGES FOR THE SEQUENTIAL MONITORING OF FOCAL ISCHEMIC LESIONS IN THE RAT-BRAIN, Magnetic resonance imaging, 11(5), 1993, pp. 675-683
The noninvasive nature of NMR imaging enables serial studies on a sing
le animal. In 12 male Wistar rats, the dynamic progression of a photoc
hemically induced (Rose Bengal) infarct was studied starting immediate
ly after induction and up to 10 days. The results demonstrated that bo
th T2- and postcontrast T1-weighted NMR images are required to discern
the time dependent dynamics of the ischemic process. The ischemic les
ion was already visible on T2-weighted images within 30 min after the
induction. Twenty-four hours after the insult, both area and intensity
reached maximum values. Hereafter and up to day 10, both parameters d
ecreased. Postcontrast T1-weighted images revealed a blood-brain barri
er (BBB) rupture immediately after the induction which persisted until
10 days after the insult. The application of contrast agents such as
Gd-DOTA or Gd-HP-DO3A also allowed the detection of 10-day-old lesions
which were not always discernable on T2-weighted images. The penetrat
ion of both contrast agents in the affected area proceeded slower the
first 5 days after the insult while at day 10, maximum contrast enhanc
ement was reached almost immediately after administration of the contr
ast agent. At 24 hr after the insult, the discrepancy between the lesi
on area as determined on T2-weighted images and on postcontrast T1-wei
ghted images was maximal. At this stage, the lesion was characterized
by a central core with a leaky BBB surrounded by a reversible zone whi
ch appeared enhanced on T2-weighted images.