Birnbaum B A, Jacobs J E, Yin D
Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
AJR Am J Roentgenol. 1995 Oct;165(4):853-8. doi: 10.2214/ajr.165.4.7676980.
The purpose of this study was to compare the degree and timing of peak hepatic enhancement, optimal scanning intervals, and optimal delay times of moderate-rate uniphasic and biphasic contrast material injection protocols for hepatic helical CT.
One hundred fifty patients were randomized into three injection protocols, receiving 42.3 g iodine (150 ml iothalamate meglumine) delivered using 3 ml/sec uniphasic, 2 ml/sec uniphasic, or biphasic (3 ml/sec [50 ml], 1 ml/sec [100 ml]) technique. Statistically fitted aortic and hepatic enhancement curves were generated from dynamic incremental CT data for each patient. Protocols were compared by maximum hepatic enhancement, and contrast enhancement indices were modeled for a 38-sec helical acquisition.
The 3 ml/sec and 2 ml/sec uniphasic protocols produced higher peak hepatic enhancement (64 +/- 15 H and 62 +/- 15 H [mean +/- 1 SD]) than the 3 ml/sec biphasic protocol (52 +/- 10 H; p < .001). Contrast enhancement indices for the 3 ml/sec uniphasic and 2 ml/sec uniphasic protocols (385 +/- 398 H/sec and 397 +/- 412 H/sec) were significantly greater than the index for the 3 ml/sec biphasic protocol (123 +/- 194 H/sec; p < .0001) at a 50-H threshold. Optimal scan delay times were 50 +/- 8, 75 +/- 7, and 119 +/- 8 sec, respectively, for the 3 ml/sec uniphasic, 2 ml/sec uniphasic, and 3 ml/sec biphasic techniques.
The moderate-rate uniphasic injections studied provided greater hepatic enhancement throughout the helical acquisition without requiring the prohibitively long delay time necessitated by the moderate-rate biphasic injection. These findings differ from prior results that showed that a uniphasic injection may provide comparable levels of hepatic enhancement when compared with a high-flow-rate biphasic injection.
本研究旨在比较肝脏螺旋CT中中等流速单相和双相造影剂注射方案的肝脏强化峰值程度及时间、最佳扫描间隔和最佳延迟时间。
150例患者被随机分为三种注射方案，分别接受以3ml/秒单相、2ml/秒单相或双相（3ml/秒[50ml]，1ml/秒[100ml]）技术注入的42.3g碘（150ml碘他拉酸葡甲胺）。根据每位患者的动态增量CT数据生成符合统计学的主动脉和肝脏强化曲线。通过肝脏最大强化程度比较各方案，并针对38秒螺旋扫描采集建立对比剂强化指数模型。
3ml/秒和2ml/秒单相方案产生的肝脏强化峰值（分别为64±15H和62±15H[平均值±1标准差]）高于3ml/秒双相方案（52±10H；p<0.001）。在50-H阈值下，3ml/秒单相和2ml/秒单相方案（分别为385±398H/秒和397±412H/秒）的对比剂强化指数显著高于3ml/秒双相方案（123±194H/秒；p<0.0001）。对于3ml/秒单相、2ml/秒单相和3ml/秒双相技术，最佳扫描延迟时间分别为50±8秒、75±7秒和119±8秒。
所研究的中等流速单相注射在整个螺旋扫描采集过程中能提供更强的肝脏强化，且无需中等流速双相注射所需的极长延迟时间。这些发现与之前的结果不同，之前的结果表明单相注射与高流速双相注射相比，可能提供相当的肝脏强化水平。
