Fig. 2. DeepSTD achieved high efficiency CT data compression, demonstrated on the CTSpine1K¹⁸ dataset.

a The estimated file sizes and minimum transmission time with 500 KB/s bandwidth before and after applying DeepSTD to compress the first 787 data samples by 256 × . b, The encoding quality of DeepSTD at 256 × compression ratio, in terms of intensity fidelity---average Mean Absolute Error (MAE) of 6.8 HU, Structural Similarity Index (SSIM) of 0.993, and organ segmentation precision---Dice Similarity Coefficient (DSC) of 90.55 and 95% Hausdorff Distance (HD95) of 4.52. These box plots share the same legend and show the distribution of the metrics from 157 samples: M (median, center line), Q₁ and Q₃ (first and third quartiles, box bounds), and Min and Max (whisker extents). Here the organ segmentation was performed using the UNETR++⁴³ trained on the Synapse dataset⁴⁴ for the Liver, Stomach, and Spleen, and on the CTSpine1K dataset for the Spine. c, d Visual comparison of DeepSTD's intensity fidelity after 256 × compression. We present the axial cross-sectional images at depth 511 (c) and depth 472 (d) of data #0001 in the leftmost column, two zoomed-in comparisons of two regions of interest (ROIs) in the middle columns, and their profiles on the rightmost column. e Visual comparison of the organ segmentation precision before and after applying DeepSTD for 256 × compression. We display the axial cross-sectional image at depth 497 of data sample #0431, with the color-coded segmentation results overlaid on top. The differences between segmentation results on the original and compression versions are also shown alongside for better visualization, with true positives (TP), false positives (FP), and false negatives (FN) highlighted in different colors. f Encoding (left) and decoding (right) time breakdown of DeepSTD between shape and texture, recorded at 256 × compression ratio and using a single RTX 3090 GPU. g–i Comparison of DeepSTD and other baseline algorithms at different compression ratios, in terms of intensity fidelity---MAE and SSIM (g), downstream organ segmentation precision---DSC and HD95 (h), and compression speed (i).