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Erschienen in:
01.06.2015 | Chest
Chest CT using spectral filtration: radiation dose, image quality, and spectrum of clinical utility
Erschienen in: European Radiology | Ausgabe 6/2015
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Objectives
To determine the radiation dose, image quality, and clinical utility of non-enhanced chest CT with spectral filtration.
Methods
We retrospectively analysed 25 non-contrast chest CT examinations acquired with spectral filtration (tin-filtered Sn100 kVp spectrum) compared to 25 examinations acquired without spectral filtration (120 kV). Radiation metrics were compared. Image noise was measured. Contrast-to-noise-ratio (CNR) and figure-of-merit (FOM) were calculated. Diagnostic confidence for the assessment of various thoracic pathologies was rated by two independent readers.
Results
Effective chest diameters were comparable between groups (P = 0.613). In spectral filtration CT, median CTDIvol, DLP, and size-specific dose estimate (SSDE) were reduced (0.46 vs. 4.3 mGy, 16 vs. 141 mGy*cm, and 0.65 vs. 5.9 mGy, all P < 0.001). Spectral filtration CT had higher image noise (21.3 vs. 13.2 HU, P < 0.001) and lower CNR (47.2 vs. 75.3, P < 0.001), but was more dose-efficient (FOM 10,659 vs. 2,231/mSv, P < 0.001). Diagnostic confidence for parenchymal lung disease and osseous pathologies was lower with spectral filtration CT, but no significant difference was found for pleural pathologies, pulmonary nodules, or pneumonia.
Conclusions
Non-contrast chest CT using spectral filtration appears to be sufficient for the assessment of a considerable spectrum of thoracic pathologies, while providing superior dose efficiency, allowing for substantial radiation dose reduction.
Key points
• Spectral filtration enables non-contrast chest CT with very high dose efficiency.
• This approach reduces CTDI
vol
, DLP, and SSDE (effective chest diameter 28 cm).
• Lung nodules, pneumonia, and pleural pathologies can be assessed with uncompromised confidence.