采用灌注磁共振成像测量缺血脑组织和正常脑组织达到峰值的标准化时间。
Standardized time to peak in ischemic and regular cerebral tissue measured with perfusion MR imaging.
作者信息
Nasel Christian, Kronsteiner Nicole, Schindler Erwin, Kreuzer Sören, Gentzsch Stephan
机构信息
Division of Neuroradiology, Department of Radiology, University of Vienna, Austria.
出版信息
AJNR Am J Neuroradiol. 2004 Jun-Jul;25(6):945-50.
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 (r(2)=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.
背景与目的
标准化达峰时间（stdTTP）能够快速定量达峰时间测量值。据报道，stdTTP≤3.5秒为正常，且有证据表明，stdTTP≥7秒提示组织灌注严重不足。我们在急性缺血（症状发作后6小时内）、灌注关键期以及24 - 72小时后对该stdTTP进行了验证。
方法
对20例急性脑缺血患者连续进行弥散加权成像（DWI）和灌注磁共振成像检查。分析双侧半球在DWI上有（缺血性损伤）或无（无缺血性损伤）明显高信号的相应区域中stdTTP≥7秒和≤3.5秒的分布情况。11例患者进行了随访检查。
结果
缺血性损伤区域约80%的体素显示stdTTP≥7秒。无缺血性损伤区域约80%的体素stdTTP≤3.5秒。在这两种情况下，14%的stdTTP值在3.5至7秒之间。我们发现stdTTP≥7秒的区域与最终梗死灶之间存在强相关性（r² = 0.86）。
结论
stdTTP在有缺血性损伤和无缺血性损伤的区域中呈相反表现。stdTTP≥7秒（正常范围）与最终梗死灶密切相关，且在急性缺血时很可能反映了灌注严重不足以及缺血组织损伤的高可能性，而在stdTTP≤3.5秒（正常范围）的区域则不太可能出现这种情况。3.5至7秒的stdTTP对于缺血性损伤的判断不明确，可能提示灌注状况尚可耐受。
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