PURPOSE: Although time-to-maximum (Tmax) maps of the residue function has been suggested as a very promising parameter, processing for Tmax map is complex. In clinical routine, non-deconvoluted time-to-peak (TTP) maps are used to calculate hypoperfused area. We evaluated the correlation of TTP maps to calculate hypoperfused lesion volume by comparison with Tmax maps.
MATERIALS AND METHODS: MRI was performed in 44 patients with acute ischemic stroke (within 6 hours after stroke onset). The volume of hypoperfusion defined by increasing TTP thresholds (relative TTP delay of >4, >6 and >8 seconds) were compared with the volume of hypoperfusion assessed by Tmax (Tmax delay of >4, >6, >8 seconds). For the calculation of lesion volume, the mean value of gray matter (TTPGM), white matter (TTPWM), and gray-white combined area (TTPmeanGW) covering the contralateral MCA territory were subtracted from the absolute TTP values. Comparisons were performed with Pearson correlation coefficients and paired t-test.
RESULTS: The mean hypoperfusion volume at Tmax >6 and TTPmeanGW >6 seconds was 80.81±65.54 and 77.69±62.89 cm3 respectively. There is no statistically significant difference between the two values(p>0.411). The hypoperfusion volume at TTPmeanGW >6 seconds best correlated with hypoperfusion volume at Tmax 6 (r = 0.925).
CONCLUSION: TTP maps still remained suitable for evaluation of hypoperfused lesion volume for clinical routine studies.
ⓒ Korean Society of Radiology. All Rights Reserved.
SS 05 NR-02.pdf
