2.2.0 Spheroid Sprouting Assay Application Documentation

Application Name

Spheroid Sprouting Assay

Version

2.2.0

Documentation Version

19.12.2023 - 1

Input Image(s)

2D (standard and/or WSI) / Time Series / z-Stack / Multichannel Images; RGB or Grayscale (8 bit)

Input Parameter(s)

Regions of interest (optional)

Keywords

spheroid, sprouting, sprout, formation, in-vitro, angiogenesis, vessel, growth, microscopy

Short Description

Detection and quantification of sprouts in a spheroid capillary sprouting assay used for in-vitro angiogenesis research.

References / Literature

For more information regarding the assay check e.g. https://www.ncbi.nlm.nih.gov/pubmed/23911327;

Table of contents

IKOSA Prisma Spheroid Sprouting Assay

You can use this image analysis application or any of our other applications in your account on the IKOSA platform. If it is not on the list of available applications, please contact your organization's administrator or our team at support@ikosa.ai.

Application description

This application automatically segments the body and sprouts created by endothelial cell spheroids in a 3D collagen matrix, and extracts relevant measures (number of sprouts, sprouting lengths, body measures, sprout measures). This analysis can also be performed on time lapse recordings (time series), z-stacks, or multichannel images, uploaded as 8-bit multipage TIFF files.

In the following sections, we provide the necessary input data requirements that are necessary to obtain accurate image analysis results and a description of the output files.

Input data requirements

Input image(s)

Input for this application is the following image data:

Image type

Color channels

Color depth (per channel)

Size (px)

Resolution (μm/px)

Image type

Color channels

Color depth (per channel)

Size (px)

Resolution (μm/px)

2D (standard and/or WSI),

Time Series,

Multichannel,

Z-stack*

 

Check image format File formats

3 RGB or

1 Grayscale

8 Bit

Standard and WSI:

Min: 10 x 10

Max: 6,144 x 6,144



typically: 0.3 - 0.7

Image content

Transmitted light or phase contrast microscopy image of spheroid capillary sprouting assay, typically taken with 10x magnification. In case of multiple bodies in the image, the body closest to the image/ROI center is detected and used for sprout analysis.

Additional requirements: None

*Please note: Z-stack images cannot be uploaded into IKOSA but still can be analyzed via IKOSA Prisma API.

Important:

For all images, the following requirements apply:

  • The illumination must be constant throughout the image(s).

  • The sample must be in focus, i.e. no blurry regions in image(s).

Input parameter(s)

No additional input parameters are required for this application.

As an optional parameter, a single or multiple regions of interest (ROIs) can be defined in which the analysis should be performed (‘inclusion ROIs’).

Description of output files and their content

Files

File format

Description

File format

Description

1

csv

results.csv:

A csv file containing the analysis results for the input image.

2

csv

results_01_sprouts.csv:

A csv file containing the morphometric parameters of the detected sprouts.

3

jpg

results_vis/vis.jpg (2D image, no ROI), or

results_vis/t<time-step>_z<z-layer>_c<channel>.jpg (for time series, z-stack, or multichannel image, no ROI), or

results_vis/<roi-id>.jpg (2D image, ROI <roi-id>), or

results_vis/t<time-step>_z<z-layer>_c<channel>_<roi-id>.jpg (for time series, z-stack, or multichannel image, ROI <roi-id>):

A visualization of the detection.

  • The segmented body is shown in yellow, different sprouts are shown in different other colors.

  • The skeleton, which is used to calculate the sprouting length, is shown in red.

  • Sprouts are labelled with white numbers that correspond to the numbers given in results_01_sprouts.csv.

  • In case of multiple bodies in the image/ROI, the body closest to the image/ROI center is detected and used for sprout analysis

Results visualization
Input image

Reference: Dr. Ingeborg Klaassen, Ocular Angiogenesis Group, Department Ophthalmology, Amsterdam UMC

Please note: These files are only created if qualitative result visualization was requested when submitting the analysis job.

4

json

annotation_results.json:

JSON file containing detected body and sprouts. The position is measured from the left upper corner (1,1) of the image.

5

json

roiMeta.json:

A json file containing all information regarding the ROIs defined for the analysis job to ensure reproducibility. Also, information regarding image and analysis dimensions is provided.

6

jpg

rois_visualization.jpg, or t<time-step>_z<z-layer>_c<channel>_rois_visualization.jpg:

An overview visualization to show locations of all analyzed ROIs for the 2D image or time step <time-step> of a time series, z-layer <z-layer> of a z-stack, or channel <channel> of a multichannel image.

7

json

jobResultBundleMeta.json:

A json file containing all information regarding the analysis job (application name and version, project, etc.) to ensure reproducibility.

Content

results.csv

Single csv-file

If one or more time steps (of a time series), z-layers (of a z-stack), or channels (of a multichannel image) were specified, the results in a specific row refer to the time step/z-layer/channel specified in the corresponding column.

If one or more ROIs were specified, the results in a specific row refer to the ROI specified in the corresponding columns, otherwise (empty ROI columns) the results refer to the whole image.

Column NO.

Column name

Examples

Value range

Description

Column NO.

Column name

Examples

Value range

Description

1

t

3

1 - 

Time step, i.e. the position of the image in the time series.

2

z

5

1 - 

z-layer, i.e. the position of the layer in the z-stack.

3

c

2

1 - 

Channel, i.e. the position of the channel in the multichannel image.

4

roi_id

ROI-03

ROI-01 - 

<roi-id> starting from “ROI-01”. Empty, if no inclusion ROI is specified and the whole image was analyzed.

5

roi_name

“central”

text

Custom text to identify the ROI. Empty, if no inclusion ROI is specified and the whole image was analyzed.

6

roi_size [Px^2]

1212212

1 -

Size of the ROI that was analyzed in pixels^2. The size of the whole image is given if no inclusion ROI is specified and the whole image was analyzed.

7

number_of_sprouts

26

0 - 

Number of detected sprouts.

8

sprouts_total_length [Px]

1004

0 -

Total length of all sprouts in pixels.

9

sprouts_total_area [Px^2]

3756

0 - 

Total area of all sprouts in pixels^2.

10

body_area [Px^2]

58775

0 -

Area of body in pixels^2.

11

body_circularity

0.76

0 - 1

Circularity of the body calculated as

where A denotes the area of the body and P the perimeter of the body.

Note: Due to the discrete nature of images, the calculation of the perimeter can only be approximated. Therefore, the circularity of a body being a circle, results in a value of approximately 0.9. Theoretically, a circle has a value of 1.0. [1]

[1] Bottema, Murk J. "Circularity of objects in images." 2000 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No. 00CH37100). Vol. 4. IEEE, 2000.

Error information

More information about errors can be found in the Application Error Documentation.

Contact

If you have any questions about this app, as well as suggestions or ideas for new ones, email us at support@ikosa.ai.

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