Downloading MRIcro 1.9.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This free Mac app is a product of Christopher Rorden.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The program lies within Design & Photo Tools, more precisely Viewers & Editors.
From the developer:
MRIcro is a small program that runs on Apple OS X for viewing the NIfTI format of medical images popular with scientists (medical DICOM images can be converted to NIfTI using tools like dcm2nii). This software can be used to inspect images from many different modalities including Magnetic Resonance Imaging (MRI), Computerized Axial Tomography (CAT, CT), Positron Emission Tomography (PET), Scanning Electron Microscopes (SEM) and 3D ultrasounds.
You may want to check out more software for Mac, such as MRIcro, which might be related to MRIcro.