Chest CT using spectral filtration: radiation dose, image quality, and spectrum of clinical utility

• Published in: European radiology Vol. 25; no. 6; pp. 1598 - 1606
• Main Authors: Braun, Franziska M., Johnson, Thorsten R. C., Sommer, Wieland H., Thierfelder, Kolja M., Meinel, Felix G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2015; Springer Nature B.V
• Subjects: Aged; Chest; Diagnostic Radiology; Efficiency; Female; Humans; Image Processing, Computer-Assisted - methods; Imaging; Internal Medicine; Interventional Radiology; Lung - diagnostic imaging; Lung diseases; Lung Diseases - diagnostic imaging; Male; Medical screening; Medicine; Medicine & Public Health; Middle Aged; Neuroradiology; Observer Variation; Patients; Pneumonia; Radiation; Radiation Dosage; Radiographic Image Enhancement - methods; Radiology; Reproducibility of Results; Retrospective Studies; Tomography; Tomography, X-Ray Computed - methods; Ultrasound; Radiation dose; Pneumonia; Thorax; X-ray computed tomography; Spectral filtration
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-014-3559-1

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 CTDI vol , 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 .