There are moderate atherosclerotic vascular calcifications of the thoracic aorta without aneurysm.

–Atherosclerotic calcifications can only be vascular. It’s redundant to use the adjective “vascular”.

-“without aneurysm” is and adjective phrase whose intent is to modify aorta, but actually modifies calcifications.

-don’t need to say “There are”. If there weren’t calcifications, you couldn’t describe them.

possible rewrite: Moderately calcified aorta. No aneurysm.