Comparative evaluation of image quality among different detector configurations using area detector computed tomography
Comparative evaluation of image quality among different detector configurations using area detector computed tomography
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DOI：
10.1007/s12194-017-0437-y
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发表时间：
2018-03-01
影响因子：
1.6
通讯作者：
Funahashi, Masao
中科院分区：
文献类型：
--
作者：
Miura, Yohei;Ichikawa, Katsuhiro;Funahashi, Masao
320排探测器计算机断层扫描（CT）系统，即区域探测器CT (ADCT)，可以进行螺旋扫描，探测器配置为4-，16-,32-,64-,80-，100-和160-探测器常规CT检查。本研究旨在比较不同探测器配置下螺旋扫描模式获得的图像质量。利用调制传递函数（MTF）和噪声功率谱（NPS）测量图像质量。基于预白化定理，计算系统性能函数SP为MTF2/NPS，并对不同配置进行比较。5种探测器配置，即0.5 × 16mm（16排），0.5 × 64mm（64排），0.5 × 80mm（80排），0.5 × 100mm（100排）和0.5 × 160mm（160排），使用25 mGy的恒容CT剂量指数（CTDIvol）进行比较，模拟成人腹部扫描，并具有恒定的有效mAs值。MTF采用钢丝法测量，NPS采用直径为20 cm且含量均匀的模体图像测量。对于恒定的CTDIvol， 80行配置的SP最好，其次是64行、160行、16行和100行配置。与80行配置相比，100行和160行配置的速率降低了大约30%。对于恒定的有效mAs， 100排和160排配置的SPs显著低于其他三种探测器配置。在需要剂量效率而不是扫描速度的情况下，80排和64排配置是足够的。
The 320-detector row computed tomography (CT) system, i.e., the area detector CT (ADCT), can perform helical scanning with detector configurations of 4-, 16-, 32-, 64-, 80-, 100-, and 160-detector rows for routine CT examinations. This phantom study aimed to compare the quality of images obtained using helical scan mode with different detector configurations. The image quality was measured using modulation transfer function (MTF) and noise power spectrum (NPS). The system performance function (SP), based on the pre-whitening theorem, was calculated as MTF2/NPS, and compared between configurations. Five detector configurations, i.e., 0.5 x 16 mm (16 row), 0.5 x 64 mm (64 row), 0.5 x 80 mm (80 row), 0.5 x 100 mm (100 row), and 0.5 x 160 mm (160 row), were compared using a constant volume CT dose index (CTDIvol) of 25 mGy, simulating the scan of an adult abdomen, and with a constant effective mAs value. The MTF was measured using the wire method, and the NPS was measured from images of a 20-cm diameter phantom with uniform content. The SP of 80-row configuration was the best, for the constant CTDIvol, followed by the 64-, 160-, 16-, and 100-row configurations. The decrease in the rate of the 100- and 160-row configurations from the 80-row configuration was approximately 30%. For the constant effective mAs, the SPs of the 100-row and 160-row configurations were significantly lower, compared with the other three detector configurations. The 80- and 64-row configurations were adequate in cases that required dose efficiency rather than scan speed.