Dynamic perfusion CT: optimizing the temporal resolution and contrast volume for calculation of perfusion CT parameters in stroke patients.
Dynamic perfusion CT: optimizing the temporal resolution and contrast volume for calculation of perfusion CT parameters in stroke patients.
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发表时间：
2004-05
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通讯作者：
M. Wintermark;Wade S. Smith;N. Ko;M. Quist;P. Schnyder;W. Dillon
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作者：
M. Wintermark;Wade S. Smith;N. Ko;M. Quist;P. Schnyder;W. Dillon
背景与目的动态灌注CT （PCT）涉及许多参数。我们评估了时间采样率和造影剂体积的影响。方法60例缺血性半球脑卒中患者接受PCT治疗，每组15例患者分别给予30、40、50、60 mL造影剂。在0.5、1、2、3、4、5和6秒的时间采样间隔下，计算区域脑血容量（rCBV）、区域脑血流量（rCBF）、平均过境时间（MTT）和峰值时间（TTP）图。结果进行统计学比较。信噪比（SNRs）、动脉入口到静脉出口的持续时间和辐射剂量也被评估。与间隔1秒的值相比，增加时间采样间隔会导致rCBV、rCBF和TTP的显著高估，而MTT的显著低估。对于30、40、50和60毫升的剂量，避免这些影响的最大允许间隔分别为2、3、3和4秒。对比剂分别在36秒、42秒、42秒和48秒后，97.5%的患者出现静脉流出。信噪比与音量无关。有效辐射剂量在0.852至1.867毫西弗之间变化，取决于方案。2次40-mL剂量的电影模式和1次60-mL剂量的切换台技术的剂量最低。结论在不影响PCT定量准确性的情况下，采用大于1秒的时间采样间隔可以降低辐射剂量，增加采样间隔可以增加空间覆盖率。
BACKGROUND AND PURPOSE Numerous parameters are involved in dynamic perfusion CT (PCT). We assessed the influence of the temporal sampling rate and the volume of contrast material. METHODS Sixty patients with ischemic hemispheric stroke lasting > or = 12 hours underwent PCT. Groups of 15 patients each received 30, 40, 50, or 60 mL of contrast agent. Regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), mean transit time (MTT), and time-to-peak (TTP) maps were calculated for temporal sampling intervals of 0.5, 1, 2, 3, 4, 5, and 6 seconds. Results were statistically compared. Signal-to-noise ratios (SNRs), duration of arterial entrance to venous exit, and radiation dose were also assessed. RESULTS Increasing temporal sampling intervals lead to significant overestimation of rCBV, rCBF, and TTP and significant underestimation of MTT compared with values for an interval of 1 second. Maximal allowable intervals to avoid these effects were 2, 3, 3, and 4 seconds for 30, 40, 50, and 60-mL boluses, respectively. Venous exit of contrast material occurred in 97.5% of patients after 36, 42, 42, and 48 seconds, respectively, for the four volumes. SNRs did not differ with volume. The effective radiation dose varied between 0.852 and 1.867 mSv, depending on the protocol. The cine mode with two 40-mL boluses and the toggling-table technique with one 60-mL bolus had the lowest doses. CONCLUSION Temporal sampling intervals greater than 1 second can be used without altering the quantitative accuracy of PCT. Increased sampling intervals reduce the radiation dose and may allow for increased spatial coverage.