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The official repository of the 2019 Kidney and Kidney Tumor Segmentation Challenge


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NEW: The KiTS23 Challenge is Underway!

See the KiTS23 Homepage for more details, including:

  • A larger dataset
  • Additional contrast phases


The official 2019 KiTS Challenge repository.


To get the data for this challenge, please clone this repository (~500MB), and then run For example

git clone
cd kits19
pip3 install -r requirements.txt
python3 -m starter_code.get_imaging

This will download the much larger and static image files from a separate source. The data/ directory should then be structured as follows

├── case_00000
|   ├── imaging.nii.gz
|   └── segmentation.nii.gz
├── case_00001
|   ├── imaging.nii.gz
|   └── segmentation.nii.gz
├── case_00209
|   ├── imaging.nii.gz
|   └── segmentation.nii.gz
└── kits.json

We've provided some basic Python scripts in starter_code/ for loading and/or visualizing the data.

Loading Data

from starter_code.utils import load_case

volume, segmentation = load_case("case_00123")
# or
volume, segmentation = load_case(123)

Will give you two Nifty1Images. Their shapes will be (num_slices, height, width), and their pixel datatypes will be np.float32 and np.uint8 respectively. In the segmentation, a value of 0 represents background, 1 represents kidney, and 2 represents tumor.

For information about using a Nifty1Image, see the Nibabel Documentation (Getting Started)

Visualizing Data

The file will dump a series of PNG files depicting a case's imaging with the segmentation label overlayed. By default, red represents kidney and blue represents tumor.

From Bash:

python3 starter_code/ -c case_00123 -d <destination>
# or
python3 starter_code/ -c 123 -d <destination>

From Python:

from starter_code.visualize import visualize

visualize("case_00123", <destination (str)>)
# or
visualize(123, <destination (str)>)

Voxel Spacing

Each Nift1Image object has an attribute called affine. This is a 4x4 matrix, and in our case, it takes the value

array([[0.                          , 0.                      , -1*captured_pixel_width , 0. ],
       [0.                          , -1*captured_pixel_width , 0.                      , 0. ],
       [-1*captured_slice_thickness , 0.                      , 0.                      , 0. ],
       [0.                          , 0.                      , 0.                      , 1. ]])

This information is also available in data/kits.json. Since this data was collected during routine clinical practice from many centers, these values vary quite a bit.

Since spatially inconsistent data might not be ideal for machine learning applications, we have created a branch called interpolated with the same data but with the same affine transformation for each patient.

array([[ 0.        ,  0.        , -0.78162497,  0.        ],
       [ 0.        , -0.78162497,  0.        ,  0.        ],
       [-3.        ,  0.        ,  0.        ,  0.        ],
       [ 0.        ,  0.        ,  0.        ,  1.        ]])

Labeling Errors

We've gone to great lengths to produce the best segmentation labels that we could. That said, we're certainly not perfect. In an attempt to strike a balance between quality and stability, we've decided on the following policy:

If you find an problem with the data, please submit an issue describing it.

Challenge Results and References

The KiTS19 challenge was held in conjunction with MICCAI 2019 in Shenzhen, China. The official leaderboard for the challenge can be found here, and the live leaderboard for new submissions can be found on

A paper describing the results and conclusions of the challenge has been accepted at Medical Image Analysis. For further reading, an in-depth description of how the dataset was collected an annotated can be found on arxiv. If this data is useful to your research, please cite these papers as

  title={The state of the art in kidney and kidney tumor segmentation in contrast-enhanced CT imaging: Results of the KiTS19 Challenge},
  author={Heller, Nicholas and Isensee, Fabian and Maier-Hein, Klaus H and Hou, Xiaoshuai and Xie, Chunmei and Li, Fengyi and Nan, Yang and Mu, Guangrui and Lin, Zhiyong and Han, Miofei and others},
  journal={Medical Image Analysis},
  title={The kits19 challenge data: 300 kidney tumor cases with clinical context, ct semantic segmentations, and surgical outcomes},
  author={Heller, Nicholas and Sathianathen, Niranjan and Kalapara, Arveen and Walczak, Edward and Moore, Keenan and Kaluzniak, Heather and Rosenberg, Joel and Blake, Paul and Rengel, Zachary and Oestreich, Makinna and others},
  journal={arXiv preprint arXiv:1904.00445},


The official repository of the 2019 Kidney and Kidney Tumor Segmentation Challenge







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