This paper summarizes a Symposium on “Radiation risks of the central nervous system” held virtually at from the 67th Annual Meeting of the Radiation Research Society, 3-6 October 2021. Repeated low-dose radiation exposure over a certain period could lead to reduced neuronal proliferation, altered neurogenesis, neuroinflammation and various neurological complications, including psychological consequences, necessitating further research in these areas. Four speakers from radiation biology, genetics and epidemiology presented the latest data from their studies seeking insights into this important topic. This symposium highlighted a new and important direction for further research on mental health disorders, neurodegenerative conditions and cognitive impairment. Future studies will examine risks of mental and behavioral disorders and neurodegenerative diseases following protracted radiation exposures to better understand risks of occupational exposures as well as provide insights into risks from exposures to galactic cosmic rays.

Background: Aortic conduit pseudoaneurysms are rare complications of surgical aortic root replacements. These complications are typically treated with a redo-sternotomy, but these surgeries carry high mortality rates, and patients may not always be good surgical candidates. There have been a few reported cases where aortic pseudoaneurysms have been successfully treated percutaneously with both short- and long-term success. We describe a case were a sub-annular aortic root pseudoaneurysm was closed using an Amplatzer Vascular Plug 2 device. Case summary: A 68-year-old man was admitted to the hospital 6 weeks after surgical aortic valve and aortic root replacement undergone for prosthetic valve endocarditis. On computed tomography, he was found to have a large fluid collection with extravasation into a false lumen located on the right side of the ascending aorta. Diagnostic catheterization confirmed flow into the pseudoaneurysm cavity from a sub-annular location. This defect was then closed using an Amplatzer Vascular Plug 2 device, with no residual flow or concern for re-opening at 8 months follow-up. Discussion: This case presents the first documented use of an Amplatzer Vascular Plug 2 to close an aortic root pseudoaneurysm in the sub-annular location. Heart team discussion is crucial in determining whether surgical or percutaneous treatment management should be performed. This case highlights a novel treatment method for sub-annular aortic root pseudoaneurysms which can be considered an alternative to surgery and potentially life-saving for high-risk patients.

A 65-year-old male with CCS II angina refractory to medications presented for coronary angiography. This showed a large vascular arcade and fistulas extending from his proximal LAD to his pulmonary artery (Figure 1A, Supplementary material online—Movie S1) and a smaller fistula from the conus artery to the pulmonary artery (Figure 1B, Supplementary material online—Movie S2). Haemodynamic measurements of the conus to PA fistula were negative with an instantaneous wave-free ratio (iFR) of 0.95 and a fractional flow reserve (FFR) of 0.89. iFR and FFR of the LAD to PA fistula were positive however with an iFR of 0.89 and an FFR of 0.80. Given the symptoms and presence of coronary steal, the fistula was successfully coiled (Figure 1C) and there was subsequent improvement of the iFR to 0.94 and FFR to 0.89. The patient remained asymptomatic for 4 weeks and then developed recurrent, progressive angina prompting repeat angiography. This showed minimal residual flow from the LAD fistula with an iFR of 0.95 in the LAD. Angiography with selective engagement of the conus showed significantly increased flow from the conus:PA fistula (Figure 1D). The second fistula was successfully coiled (Figure 1E and F) with complete cessation of flow into the PA and normalization of coronary haemodynamics. The patient has subsequently remained anginal free.