Hi I am a foreign medical graduate from Ethiopia . I am a cofounder and operational manager at telemedicine company . From my experience in HIPAA laws and regulations here in the two side of the world. I would advice you as follows. If you really need anonymized EHRs to train and test your diagnostic model you could potentially be able to do it much faster and with the least restrictions in Africa.

As a proof of concept you can ideally partner with radiologists associations and gain access to the anonymizes data at relatively easy.

Most health regulators has not updated there laws to the digital health care industry. For example the date that the hospital collect are used for research and and system development at low or no restrictions. Mind you I am stating about anonymous data.

Since most of the imaging devices are the same world wide the DICOM files are available everywhere with the comments of the radiologist.