RT Journal Article
SR Electronic
T1 Standardized Time to Peak in Ischemic and Regular Cerebral Tissue Measured with Perfusion MR Imaging
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 945
OP 950
VO 25
IS 6
A1 Christian Našel
A1 Nicole Kronsteiner
A1 Erwin Schindler
A1 Sören Kreuzer
A1 Stephan Gentzsch
YR 2004
UL http://www.ajnr.org/content/25/6/945.abstract
AB BACKGROUND AND PURPOSE: Standardized time to peak (stdTTP) enables a quick quantification of time to peak measurements. An stdTTP ≤3.5 seconds is reported to be regular, and evidence suggests that an stdTTP ≥7 seconds indicates critically perfused tissue. We verified this stdTTP in acute ischemia (within the first 6 hours after the onset of symptoms), when perfusion is critical, and after 24–72 hours.METHODS: Combined diffusion-weighted imaging (DWI) and perfusion MR imaging was performed in 20 consecutive patients with acute cerebral ischemia. Distributions of stdTTP ≥7 and ≤3.5 seconds were analyzed in corresponding regions with (ischemic injury) or without (no ischemic injury) substantial hyperintensity on DWI in both hemispheres. Follow-up examinations were available in 11 patients.RESULTS: About 80% of voxels in regions with ischemic injury showed an stdTTP ≥7 seconds. StdTTP of about 80% of voxels was ≤3.5 seconds in regions without ischemic injury. In both conditions, 14% of stdTTP values were between 3.5 and 7 seconds. We found a strong correlation between areas with stdTTP ≥7 seconds and resulting infarct (r2=0.86).CONCLUSION: StdTTP is reciprocal in regions with and without ischemic injury. An stdTTP ≥7 seconds (regular range) is strongly correlated with resulting infarct and reflects critical perfusion with a high probability of ischemic tissue injury in acute ischemia, whereas this is unlikely in regions with stdTTP ≤3.5 seconds (regular range). An stdTTP of 3.5–7 seconds is equivocal concerning ischemic injury and may indicate a tolerable perfusion condition.