Bohy Pascale, de Maertelaer Viviane, Roquigny Aymeric, Keyzer Caroline, Tack Denis, Gevenois Pierre Alain
Department of Radiology, Hôpital Erasme, Université Libre de Bruxelles, Route de Lennik 808, 1070 Brussels, Belgium.
Radiology. 2007 Aug;244(2):524-31. doi: 10.1148/radiol.2442060606.
To compare standard-dose and simulated low-dose multidetector computed tomography (CT) in patients suspected of having lumbar disk herniation.
The institutional review board approved the research protocol with a waiver of patient informed consent. Sixty consecutive patients underwent multidetector CT with four detector rows at 1 mm collimation at 140 kVp, with tube current-time product adapted to body mass index (BMI): 200 (BMI< 22 kg/m(2)), 300 (BMI > or =22 to <30 kg/m(2)), and 400 effective mAs (BMI > or =30 kg/m(2)). Simulated doses at 65%, 50%, 35%, and 20% of the dose were used for acquisition. During two separate sessions, three independent radiologists coded each of three caudal disks as normal, bulging, or herniated and graded canal and foramen compromise. Median numbers of discrepancies between the standard and reduced doses were compared with Friedman and Wilcoxon tests. Agreements within and between readers were evaluated through kappa statistics.
Dose reduction had no effect on a reader's ability to identify bulging disks (P = .128) and left and right foramen compromises (P = .413 and .665, respectively). However, for normal disks (P = .002), herniated disks (P = .004), and canal compromise (P = .002), dose reduction did have a significant effect. For normal disks and canal compromise, a reduction dose effect was not detected at 65% (P = .121 and .250, respectively) but appeared at 50% (P = .004 and .008, respectively). For herniation, a dose reduction effect was detected at 35% (P = .031). Agreements within and between readers ranged from poor to excellent and tended to decrease with dose reduction.
For patients suspected of having lumbar disk herniation, tube charge settings could be reduced to 65% of the standard dose adapted to the BMI.
比较标准剂量与模拟低剂量多排螺旋计算机断层扫描（CT）在疑似腰椎间盘突出症患者中的应用。
机构审查委员会批准了本研究方案，豁免了患者的知情同意。60例连续患者接受了四排探测器的多排螺旋CT检查，准直为1mm，管电压140kVp，管电流-时间乘积根据体重指数（BMI）进行调整：200（BMI<22kg/m²）、300（BMI≥22至<30kg/m²）和400有效mAs（BMI≥30kg/m²）。使用65%、50%、35%和20%剂量的模拟剂量进行采集。在两个不同的时间段内，三名独立的放射科医生将三个尾侧椎间盘分别编码为正常、膨出或突出，并对椎管和椎间孔受压情况进行分级。采用Friedman检验和Wilcoxon检验比较标准剂量和降低剂量之间差异的中位数。通过kappa统计评估读者之间以及读者内部的一致性。
剂量降低对读者识别膨出椎间盘（P = 0.128）以及左右椎间孔受压情况（分别为P = 0.413和0.665）的能力没有影响。然而，对于正常椎间盘（P = 0.002）、突出椎间盘（P = 0.004）和椎管受压情况（P = 0.002），剂量降低确实有显著影响。对于正常椎间盘和椎管受压情况，在65%剂量时未检测到降低剂量的影响（分别为P = 0.121和0.250），但在50%剂量时出现影响（分别为P = 0.004和0.008）。对于椎间盘突出，在35%剂量时检测到剂量降低的影响（P = 0.031）。读者之间以及读者内部的一致性从差到优不等，并且倾向于随着剂量降低而降低。
对于疑似腰椎间盘突出症的患者，管电荷设置可降低至根据BMI调整的标准剂量的65%。
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