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Erschienen in:
26.01.2016 | Chest
Performance of ultralow-dose CT with iterative reconstruction in lung cancer screening: limiting radiation exposure to the equivalent of conventional chest X-ray imaging
Erschienen in: European Radiology | Ausgabe 10/2016
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Objective
To investigate the detection rate of pulmonary nodules in ultralow-dose CT acquisitions.
Materials and methods
In this lung phantom study, 232 nodules (115 solid, 117 ground-glass) of different sizes were randomly distributed in a lung phantom in 60 different arrangements. Every arrangement was acquired once with standard radiation dose (100 kVp, 100 references mAs) and once with ultralow radiation dose (80 kVp, 6 mAs). Iterative reconstruction was used with optimized kernels: I30 for ultralow-dose, I70 for standard dose and I50 for CAD. Six radiologists examined the axial 1-mm stack for solid and ground-glass nodules. During a second and third step, three radiologists used maximum intensity projection (MIPs), finally checking with computer-assisted detection (CAD), while the others first used CAD, finally checking with the MIPs.
Results
The detection rate was 95.5 % with standard dose (DLP 126 mGy*cm) and 93.3 % with ultralow-dose (DLP: 9 mGy*cm). The additional use of either MIP reconstructions or CAD software could compensate for this difference. A combination of both MIP reconstructions and CAD software resulted in a maximum detection rate of 97.5 % with ultralow-dose.
Conclusion
Lung cancer screening with ultralow-dose CT using the same radiation dose as a conventional chest X-ray is feasible.
Key points
• 93.3 % of all lung nodules were detected with ultralow-dose CT.
• A sensitivity of 97.5 % is possible with additional image post-processing.
• The radiation dose is comparable to a standard radiography in two planes.
• Lung cancer screening with ultralow-dose CT is feasible.