For a thoracic aortic aneurysm measuring 4.5 cm, it is generally recommended to have a CT scan every 6 months. This frequency allows for close monitoring of any changes in the size or shape of the aneurysm, which is crucial in determining the appropriate timing for any potential intervention. I have a transplanted aortic graft made of dacron. I'm at 4.1 cm and I get an annual CT, with contrast every other time to lessen the kidney damage. While it’s true that frequent CT scans do involve exposure to radiation, the risk of radiation-induced complications is relatively low compared to the potential risk of an undetected increase in the size of your aneurysm. The cumulative radiation exposure over several years of regular monitoring is a valid concern, but in your case, the benefits of frequent imaging likely outweigh the risks. Trust me, you want to keep a close eye on that aorta. They get one shot at fixing it and you'd better have it done BEFORE it dissects.

There are some alternative imaging techniques, like MRI, that don't involve ionizing radiation and might be suitable for long-term monitoring. However, the imaging technique you'regoingto want to use depends on a lot of factors, including the specific characteristics of your aneurysm and your overall health condition. This is a decision best made in consultation with your cardiologist or vascular surgeon. I get 8K hires imaging done at the University of Minnesota - Fulton Street Imaging. It's worth it to travel to the best imaging center in your area and have it done right. I also get a CD-ROM with all my pictures every year and look at it myself (because, well, I'm THAT guy). There is really cool free software for Windows and the MAc that allows you to reconstruct the images in 3D and look at them. I highly recommend it. The more educated you are about your body the better your odds. Your doctor will tailor the monitoring schedule to your specific case. They may also consider alternative imaging methods if they deem it appropriate, ensuring that you are monitored effectively while minimizing any unnecessary risks.