Helical CT for nephrolithiasis and ureterolithiasis: Comparison of conventional and reduced radiation-dose techniques
Helical CT for nephrolithiasis and ureterolithiasis: Comparison of conventional and reduced radiation-dose techniques
复制标题
DOI：
10.1148/radiol.2292021261
复制
发表时间：
2003-11-01
期刊：
影响因子：
19.7
通讯作者：
Nelson, RC
中科院分区：
文献类型：
--
作者：
Heneghan, JP;McGuire, KA;Nelson, RC
目得：为了确定的准确性，未增强的螺旋计算机断层扫描（CT）在减少毫安秒，因此在减少患者的辐射剂量，通过使用传统的未增强的螺旋CT作为standard.MATERIALS和METHODS：50例急性腰痛谁体重小于200磅（90公斤）前瞻性招募本研究。采用5 mm厚切片、140 kVp、135-208 mAs（平均160 mAs）和1.5（单探测器行CT）或0.75（多探测器行CT，4 x 5 mm探测器配置）螺距对俯卧位患者进行常规螺旋CT扫描。常规CT后立即进行低剂量扫描，管电流降至100 mA（平均76 mAs）。所有其他技术参数和解剖覆盖范围保持不变。三名对患者身份不知情的独立阅片员以随机顺序解读扫描结果。观察员记录结石的位置、大小和数量;继发性梗阻体征;以及其他临床相关发现。采用配对t检验和符号秩检验对高剂量和低剂量扫描进行比较。结果：发现结石33例（66%），肾结石25例（50%），梗阻性输尿管结石19例（38%）。与高剂量扫描相比，低剂量扫描确定各种结果的准确率（三位读片者的平均值）如下：肾结石，91%;输尿管结石，9490;梗阻，91%;正常结果，92%。当比较阅片者之间的解释时，标准剂量扫描的一致率为90%-95%，减少剂量扫描的一致率为90%-92%（P > 0.5）。3例患者发现无并发症的轻度憩室炎。未发现其他具有临床意义的异常。在管电流减少到100 mA导致剂量减少25%的多探测器行CT和42%的单探测器行CT.CONCLUSION：在患者体重小于200磅，未增强的螺旋CT在减少管电流为100 mA，因此在减少患者剂量，导致扫描的高精度。(C)RSNA，2003年。
PURPOSE: To determine the accuracy of unenhanced helical computed tomography (CT) performed at reduced milliampere-second, and therefore at a reduced patient radiation dose, by using conventional unenhanced helical CT as the standard.MATERIALS AND METHODS: Fifty patients with acute flank pain who weighed less than 200 lb (90 kg) were prospectively recruited for this study. Conventional helical CT scans were obtained with patients in the prone position by using 5-mm-thick sections, 140 kVp, 135-208 mAs (mean, 160 mAs), and a pitch of 1.5 (single-detector row CT) or 0.75 (multi-detector row CT, 4 x 5-mm detector configuration). Conventional CT was immediately followed by low-dose scanning, whereby the tube current was reduced to 100 mA (mean, 76 mAs). All other technical parameters and anatomic coverage remained constant. Three independent readers who were blinded to patient identity interpreted the scans in random order. The observers noted the location, size, and number of calculi; secondary signs of obstruction; and other clinically relevant findings. High- and low-dose scans were compared by using paired t tests and the signed rank test.RESULTS: Calculi were found in 33 (66%) patients; 25 (50%) had renal calculi and 19 (38%) had an obstructing ureteral calculus. The accuracy rates (averaged over the three readers) for determining the various findings on the low-dose scan compared with the high-dose scan were as follows: nephrolithiasis, 91 %; ureterolithiasis, 9490; obstruction, 91%; and normal findings, 92%. When interpretations between readers were compared, agreement rates were 90%-95% for standarddose scans and 90%-92% for reduced-dose scans (P >.5). Uncomplicated mild diverticulitis was found in three patients. No other clinically important abnormality was identified. A reduction in the tube current to 100 mA resulted in a dose reduction of 25% for multi-detector row CT and 42% for single-detector row CT.CONCLUSION: In patients who weighed less than 200 lb, unenhanced helical CT performed at a reduced tube current of 100 mA, and therefore at a reduced patient dose, resulted in scans of high accuracy. (C) RSNA, 2003.