Jungblut Lisa, Blüthgen Christian, Polacin Malgorzata, Messerli Michael, Schmidt Bernhard, Euler Andre, Alkadhi Hatem, Frauenfelder Thomas, Martini Katharina
From the Institute of Diagnostic and Interventional Radiology.
Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Invest Radiol. 2022 Feb 1;57(2):108-114. doi: 10.1097/RLI.0000000000000814.
The aim of this study was to evaluate the image quality (IQ) and performance of an artificial intelligence (AI)-based computer-aided detection (CAD) system in photon-counting detector computed tomography (PCD-CT) for pulmonary nodule evaluation at different low-dose levels.
An anthropomorphic chest-phantom containing 14 pulmonary nodules of different sizes (range, 3-12 mm) was imaged on a PCD-CT and on a conventional energy-integrating detector CT (EID-CT). Scans were performed with each of the 3 vendor-specific scanning modes (QuantumPlus [Q+], Quantum [Q], and High Resolution [HR]) at decreasing matched radiation dose levels (volume computed tomography dose index ranging from 1.79 to 0.31 mGy) by adapting IQ levels from 30 to 5. Image noise was measured manually in the chest wall at 8 different locations. Subjective IQ was evaluated by 2 readers in consensus. Nodule detection and volumetry were performed using a commercially available AI-CAD system.
Subjective IQ was superior in PCD-CT compared with EID-CT (P < 0.001), and objective image noise was similar in the Q+ and Q-mode (P > 0.05) and superior in the HR-mode (PCD 55.8 ± 11.7 HU vs EID 74.8 ± 5.4 HU; P = 0.01). High resolution showed the lowest image noise values among PCD modes (P = 0.01). Overall, the AI-CAD system delivered comparable results for lung nodule detection and volumetry between PCD- and dose-matched EID-CT (P = 0.08-1.00), with a mean sensitivity of 95% for PCD-CT and of 86% for dose-matched EID-CT in the lowest evaluated dose level (IQ5). Q+ and Q-mode showed higher false-positive rates than EID-CT at lower-dose levels (IQ10 and IQ5). The HR-mode showed a sensitivity of 100% with a false-positive rate of 1 even at the lowest evaluated dose level (IQ5; CDTIvol, 0.41 mGy).
Photon-counting detector CT was superior to dose-matched EID-CT in subjective IQ while showing comparable to lower objective image noise. Fully automatized AI-aided nodule detection and volumetry are feasible in PCD-CT, but attention has to be paid to false-positive findings.
本研究旨在评估基于人工智能(AI)的计算机辅助检测(CAD)系统在光子计数探测器计算机断层扫描(PCD-CT)中对不同低剂量水平下肺结节评估的图像质量(IQ)和性能。
使用含14个不同大小(范围为3-12mm)肺结节的仿真胸部模型,在PCD-CT和传统能量积分探测器CT(EID-CT)上进行成像。通过将IQ水平从30调整到5,以递减的匹配辐射剂量水平(容积计算机断层扫描剂量指数范围为1.79至0.31mGy),分别使用3种厂商特定的扫描模式(QuantumPlus [Q+]、Quantum [Q]和高分辨率[HR])进行扫描。在胸壁的8个不同位置手动测量图像噪声。由2名读者共同评估主观IQ。使用商用AI-CAD系统进行结节检测和体积测量。
与EID-CT相比,PCD-CT的主观IQ更高(P < 0.001),Q+和Q模式下的客观图像噪声相似(P > 0.05),HR模式下的客观图像噪声更低(PCD为55.8±11.7HU,EID为74.8±5.4HU;P = 0.01)。高分辨率在PCD模式中显示出最低的图像噪声值(P = 0.01)。总体而言,AI-CAD系统在PCD-CT和剂量匹配的EID-CT之间对肺结节检测和体积测量的结果相当(P = 0.08-1.00),在最低评估剂量水平(IQ5)下,PCD-CT的平均灵敏度为95%,剂量匹配的EID-CT为86%。在较低剂量水平(IQ10和IQ5)下,Q+和Q模式的假阳性率高于EID-CT。即使在最低评估剂量水平(IQ5;CDTIvol,0.41mGy),HR模式的灵敏度也达到100%,假阳性率为1。
光子计数探测器CT在主观IQ方面优于剂量匹配的EID-CT,同时客观图像噪声相当。在PCD-CT中,全自动AI辅助结节检测和体积测量是可行的,但必须注意假阳性结果。