Table 1.
Studiesincluded in the systematic review, divided into the four previously defined categories, along with their main parameters. Mag.: magnification level. n/a: not available. #: Number. xAI: studies that provide elements for explainable AI, e.g., GradCAMs or attention mechanism.
| Study | Year | Studied Structures | Mag. | # WSIs | Patch Size | Pre-Processing | DL Method | GPU Used | # Sources | Metadata | xAI | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Comparison vs. pathologists | Ba et al. [42] | 2021 | Tumor | 40× | 781 | 256 × 256 | Image quality review | CNN and random forest | n/a | 2 | no | yes |
| Bao et al. [36] | 2022 | Tumor | 40× | 981 | 224 × 224 | Random patch selection, structure-preserving color normalization | ResNet-152 | NVIDIA GTX 2080Ti | 3 | no | no | |
| Brinker et al. [43] | 2022 | Tumor | n/a | 100 | n/a | n/a | ResNeXt50 | n/a | n/a | no | yes | |
| Hekler et al. [14,15] | 2019 | Tumor | 10× | 695 | n/a | n/a | ResNet50 | n/a | 1 | no | no | |
| Phillips et al. [27] | 2019 | Tumor, dermis, and epidermis | 40× | 50 | 512 × 512 | Subtraction | Modified FCN | NVIDIA GTX 1080 Ti | 10 † | no | yes | |
| Sturm et al. [16] | 2022 | Mitosis | 20× | 102 | n/a | n/a | n/a | n/a | 1 | yes | no | |
| Wang et al. [37] | 2020 | Tumor | 20× | 155 | 256 × 256 | Random cropping to 224 × 224, data enhancement, and augmentation | VGG16 | n/a | 2 | no | yes | |
| Xie et al. [28] | 2021 | Tumor, dermis, and epidermis | 20× | 701 | 224 × 224 | Discard blank patches (Otsu) | ResNet50 | n/a | 3 † | yes | no | |
| Xie et al. [17] | 2021 | Tumor | n/a | 841 | 256 × 256 | Discard blank patches (Otsu) | ResNet50 | NVIDIA TITAN RTX | 1 | no | yes | |
| Diagnosis | Del Amor et al. [19] | 2021 | Tumor | 10× | 51 | 512 × 512 | Discard blank patches (Otsu) | VGG16 with attention | NVIDIA DGX A100 | 1 | no | yes |
| Del Amor et al. [18] | 2022 | Tumor | 5×, 10×, 20× | 43 | 512 × 512 | Discard blank patches and with less than 20% of tissue (Otsu) | ResNet18 with late fusion of multiresolution feature maps | NVIDIA GP102 TITAN Xp | 1 | no | yes | |
| Hart el al. [34] | 2019 | Tumor | 40× | 300 | 299 × 299 | n/a | InceptionV3 | 4 NVIDIA GeForce GTX 1080 | n/a | no | yes | |
| Höhn et al. [38] | 2021 | Tumor | n/a | 431 | 512 × 512 | Remove patches with more than 50% of background, random selection of 100 tiles per slide | ResNeXt50 with fusion model to combine patient data and image features | NVIDIA GeForce GTX 745 | 2 | yes | yes | |
| Li et al. [29] | 2021 | Tumor, dermis, and epidermis | 20× | 701 | 224 × 224 | Discard blank patches (Otsu) | ResNet50 | n/a | 2 † | yes | yes | |
| Van Zon et al. [20] | 2020 | Tumor | 40× | 563 | 256 × 256 | Data augmentation | U-Net | NVIDIA 2080 | 1 | no | no | |
| Xie et al. [21] | 2021 | Tumor | 40× | 312 | 500 × 500 | Filter out background tiles | Transfer learning vs fully trained: InceptionV3, ResNet50, MobileNet | n/a | 1 | no | no | |
| Prognosis | Brinker et al. [13] | 2021 | Tumor | n/a | 415 | 256 × 256 | n/a | ResNeXt50 | n/a | 3 | yes | no |
| Kim et al. [30] | 2022 | Tumor, inflammatory cells, and other | 20× | 305 | 299 × 299 | n/a | Inception v3 with fivefold cross-validation | n/a | 2 † | yes | no | |
| Kulkarni et al. [40] | 2020 | Tumor, inflammatory cells, and other | 40× | n/a | 500 × 500 | Downsample to 100 × 100, nuclear segmentation with watershed cell detection | n/a | n/a | 2 | yes | no | |
| Moore et al. [41] | 2021 | Tumor, inflammatory cells, and other | 40×, 20× | n/a | 100 × 100 | n/a | QuIP TIL CNN [44] | NVIDIA GP102GL [Quadro P6000] | 2 | yes | no | |
| Zormpas-Petridis et al. [31] | 2019 | Tumor, inflammatory cells, and other | 20×, 5×, 1.25× | 105 | 2000 × 2000 (20× WSIs) | n/a | Spatially constrained CNN with spatial regression, neighboring ensemble with softmax | NVIDIA Tesla P100-PCIE-16GB | 1 † | yes | no | |
| ROI/histological features | Alheejawi et al. [22] | 2021 | Tumor, inflammatory cells, and epidermis | 40× | 4 | 960 × 960 | Divide patches into 64 × 64 blocks | ResNet50 | NVIDIA GeForce GTX 745 | 1 | no | no |
| De Logu et al. [39] | 2020 | Tumor and healthy tissues | 20× | 100 | 299 × 299 | Data augmentation, discard patches with more than 50% background | Inception-ResNet-v2 | n/a | 3 | no | yes | |
| Kucharski et al. [23] | 2020 | Tumor | 10× | 70 | 128 × 128 | Data augmentation, overlapping only for minority class to balance data set | Autoencoders | n/a | 1 | no | yes | |
| Liu et al. [24] | 2021 | Tumor | 10× | 227 ROIs ‡ | 1000 × 1000 | Downscale magnification to 5× | Mask R-CNN | 4 NVIDIA GeForce GTX 1080 | 1 | no | no | |
| Nofallah et al. [25] | 2021 | Mitosis | 40× | 22 | 101 × 101 | Data augmentation | ESPNet, DenseNet, ResNet, and ShuffleNet | NVIDIA GeForce GTX 1080 | 1 | no | no | |
| Zhang et al. [26] | 2021 | Tumor | n/a | 30 | 1024 × 1024 | Data augmentation, color analysis for tissue-contained patch selection, normalization of patches to a uniform size, resize patches to 512 × 512 | CNN, feature fusion | NVIDIA RTX 2080-12G | 1 | no | no |
† At least one of the source institutions is open source, i.e., TCGA or NCI. ‡ Images are ROIs extracted from initial WSIs.