Compared to most medical imaging studies, mammograms are subject to a higher level of scrutiny. In addition to needing FDA approval, those working with mammograms must be in compliance with the Mammography Quality and Safety Act (MQSA), which defines how long studies must be saved and what kind of equipment studies can be read on.

Another noteworthy feature that sets mammograms apart from other medical images is that mammograms are almost always compared to one or two prior images. When a woman comes in for her regularly scheduled mammography exam, the physician will often place both the new and older images up on the screen in order to make a comparison and diagnosis.

These concerns are compounded by the fact that mammograms and digital breast tomosynthesis (DBT) images are typically large, dense files. All these challenges make storing mammograms in — and retrieving them from — a picture archiving and communication system (PACS) more difficult than typical medical imaging studies.

With these challenges in mind, can mammograms really be stored in a cloud-based PACS, or is this ability still out of reach?

Requirements for Storing Mammograms in the Cloud

Until recently, mammography image files have tended not to be stored in the cloud because of the issues mentioned above. Instead, mammography images have been stored onsite using a much more traditional PACS.

Despite these tendencies, the answer to the question of can mammograms be stored in the cloud is a clear yes: it's completely possible to store mammograms in the cloud. However, radiology practices looking to leverage the cloud should be sure to find a vendor who understands the issues and regulations associated with cloud storage of mammography images.

In particular, some of the features your mammography cloud PACS should include are as follows:

• A straightforward way to retrieve prior images for a particular patient. The system should be "aware" of prior images when a patient returns for another exam, automatically notifying the PACS user and identifying the location of the prior images.
  
  
• An easy way to ingest new images via CD or electronic transfer. Often women will have their latest exam at a different location than their previous exams, so it needs to be easy for the PACS to upload these prior images to the patient record when they are sent to the practice or shared by the patient.
  
  
• A compression mechanism allowing large files to be stored and retrieved faster than uncompressed raw images. The compression must be lossless, rather than lossy. This consideration should be taken into account to ensure the system is capable of both compression and decompression in an efficient manner.
  
  
• Adequate storage space. The size of cloud storage can increase dynamically, and when using the cloud, it's the vendor's responsibility rather than the health care facility's to make sure that there's always enough storage capacity. By contrast, an onsite PACS will quickly use up storage for mammography or tomosynthesis images, and the practice will need to increase the PACS storage or upgrade on a regular basis.
  
  
• A viewer that is approved for diagnostic use for mammography reading. Not all cloud PACS have an integrated medical image viewer that is approved by the FDA for diagnostic use with mammograms. Mammography reading requires an additional certification beyond the standard FDA approval, so it is important to ask your vendor if the medical image viewer associated with their cloud PACS has the appropriate approvals required in your geography. It is also important to understand the equipment calibration requirements for your monitor and workstations, as MQSA standards may apply when viewing images.

The Freedom of the Cloud

Today, cloud-based PACS have matured to the point where they can be as good as — or better than — an onsite PACS for storing mammograms. Cloud-based PACS also have the benefit of freeing their users geographically, allowing physicians to perform diagnoses even while on vacation or in an emergency simply by pulling the image up on their screen.

The MQSA sets up additional requirements for viewing mammograms that are slightly different from the standard radiology workstation. Today, there are even a few web-based viewers that are in compliance with the FDA and the MQSA for reading mammography exams, removing the final barrier to using the cloud to store mammograms.