Screening for interstitial lung disease in systemic sclerosis: the diagnostic accuracy of HRCT image series with high increment and reduced number of slices

Abstract

HRCT image series with low sampling rate allow an accurate detection of ILD with very-low-radiation dose, making this approach potentially valuable for screening in patients with SSc.

The impact of slice-reduced computed tomography on histogram-based densitometry assessment of lung fibrosis in patients with systemic sclerosis

“…A former prospective study by Winklehner et al showed that the use of a dedicated HRCT based on reduced sequential slices throughout the entire chest can detect lung fibrosis with a high diagnostic sensitivity and accuracy of both 94% with a very low radiation dose (28). Similar strategies with the aim of dose reduction in CT for other indications have also been performed by Bankier et al and de Jong et al (29,30).…”

“…Therefore, the reduced HRCT may represent a powerful tool that not only allows to visualize early ILD in SSc as shown recently (28,31), but may also be a tool to quantify subtle new fibrotic changes in lung parenchyma during follow up, especially with a significantly lower radiation exposure with a 97.4% reduction of estimated effective radiation dose in our cohort with 0.041 mSv which is in a range of a conventional chest X-ray and can be considered as a screening method for early detection and early evaluation of SSc ILD increase, rather than detection of lung fibrosis alone.…”

“…Similar strategies with the aim of dose reduction in CT for other indications have also been performed by Bankier et al and de Jong et al (29,30). The advantage of a low sampling protocol is the very low radiation dose of less than 0.028 mSv, which is in the range of a chest X-ray (28). Further Frauenfelder et al could confirm in a retrospective image analysis that by the approach of using a sequential reduced 9-slice HRCT mild ILD can reliably be detected with the advantage of a much lower radiation dose (31).…”

“…The standard HRCT was reconstructed with iterative reconstruction (SAFIRE) strength 3 and 5. Using the standard HRCT dataset a 9-slice-CT (further named reduced HRCT) was reconstructed as following: nine axial slices with an apico-basal gradient, whereas the first three slices had an increment of about 80 mm (first slice: manubrium sterni, second slice: hilum, third slice: level of lower lobe, based on increment between first and second slice); for the following 6 slices the increment was 15 mm (covering the lung basis) (28). To simulate the reproducibility of reduced HRCT retrospectively in a possible prospective setting, in a subgroup of 20 patients slightly different 9 slices with a systematic distance difference within a range of 1-3 cm in comparison to the aforementioned standardized slice levels but with the same defined increment between the slices within the same specimen was reconstructed.…”

“…Pontana et al could show, that with a dose reduction of 60%, CT images reconstructed with sinogramm-affirmed iterative reconstruction (SAFIRE) still allow a similar detection of ILD in SSc patients (27). Besides different scan parameter based dose modulations, reduction of scan range or number of images per scan can also lead to a significant dose reduction maintaining the high diagnostic sensitivity (16,28).…”