The I4 system version 1.08 is now available for download. Users must follow the defined terms and conditions for use of the system. In general, educational and public research use is free while commercial use requires a licensing fee or arrangement. Complete terms and conditions follow.

I4 System Licenses

I4 system licenses are granted free of charge to individuals using the software for educational purposes, or for research which is published in open and peer reviewed journals. Registration of such licenses with NSR is welcomed, but not required. To register, send Email to briefly describing your research and/or your interest in imaging software.

I4 system licenses for commercial purposes or other purposes not listed above are not free. Users of I4 for such purposes must either pay a licensing fee or make other arrangements with NSR to help support the continued development and support of I4. To request such licenses contact NSR via

I4 System Terms and Conditions for Use

>The I4 system is licensed, not given, to you and may only be used under the terms of the license. The NSR reserves any rights not expressly granted to you.

  • Acknowledgements: The following acknowledgment must appear in all publications for which the software is used for experimental design and/or data analysis - "The I4 system, developed in the Division of Cardiology, Department of Medicine, at the University of Washington and the Veteran's Administration Puget Sound Health Care System (supported by NIH grant HL 50239) was used in the analysis of data reported in this manuscript." Send one reprint to the NSR at the address given above. You are encouraged to notify the NSR when a manuscript is submitted giving its title, list or authors, and the name of the journal to which submitted.
  • Distribution: You may not give, rent, lease, or sell the I4 system or copies thereof without permission of the NSR. You may, however, distribute diffs to the original NSR source code, or any programs you may write that integrate with the I4 system without permission of NSR.
  • Termination: This license is effective until terminated. The license is terminated immediately without notice from the NSR if you fail to comply with any of the terms of the license. You may terminate the license at any time by destroying all copies of the software including backup copies.
  • Limited warranty and disclaimer: You acknowledge that the software may not satisfy all your requirements or be free from defects. The software and its documentation are licensed "AS IS." All implied warranties and conditions are disclaimed.
  • Limitation of remedies and damages: Your exclusive remedy for breach of warranty is the reinstallation of the software on the machines covered by this license. In no event will the NSR or its director or staff be liable to you for any consequential, incidental, or indirect damages, whether foreseeable or unforeseeable, arising from the use or inability to use the software or its documentation.

I4 System Download Procedure

  • If you are downloading for Windows-NT, see the note below before proceeding.


  • Transfer one or more of the compressed tar archives below to your computer by clicking on the appropriate link.


  • Create a directory to install the I4 system in and "cd" to that directory. We recommend /usr/local/I4.


  • Use "uncompress " to uncompressed the tar archive(s)


  • Use your local tar program to expand the archive(s). On most systems this can be done by executing

    tar xf

    once for each archive, but check your local system's documentation. Once the archives are expanded, they may be removed.


  • See further instructions in the appropriate README* files.

I4 Archives Available for Download

The I4 system version 1.08 may be downloaded in source form, or in one of several rather elderly pre-built binary distributions. Also available is a verification suite to test for proper installation of the system.

I4 system has been successfully built for Cygwin-32 for Windows-NT, however licensing issues make it difficult for NSR to offer a pre-built binary distribution on this platform. If you wish to run I4 on Windows-NT, you will need to configure Cygwin-32 on your NT box, and then build I4 from the source distribution.

Need help? Contact us

Return to the I4 System Home Page.

Model development and archiving support at provided by the following grants: NIH U01HL122199 Analyzing the Cardiac Power Grid, 09/15/2015 - 05/31/2020, NIH/NIBIB BE08407 Software Integration, JSim and SBW 6/1/09-5/31/13; NIH/NHLBI T15 HL88516-01 Modeling for Heart, Lung and Blood: From Cell to Organ, 4/1/07-3/31/11; NSF BES-0506477 Adaptive Multi-Scale Model Simulation, 8/15/05-7/31/08; NIH/NHLBI R01 HL073598 Core 3: 3D Imaging and Computer Modeling of the Respiratory Tract, 9/1/04-8/31/09; as well as prior support from NIH/NCRR P41 RR01243 Simulation Resource in Circulatory Mass Transport and Exchange, 12/1/1980-11/30/01 and NIH/NIBIB R01 EB001973 JSim: A Simulation Analysis Platform, 3/1/02-2/28/07.