What to look for?
Symptoms are worrisome for malignancy. As the abnormality will most likely not strike you on the head, the trained eye will look for solid tumours and signs of myelolymphoproliferative disease. Findings suggestive of infection or inflammation (e.g. vasculitis) are also on this list.
Still worried for malignancy after scrutinizing the study?
Not so much longer. There is no evidence of solid tumours (maybe you would appreciate a completing arterial phase study, and I wouldn't argue that). There is slight enlargement of the spleen. There is no lymphadenopathy by size or enhancement criteria. There are no acute abnormalities either, especially no convincing evidence of systemic infection (other than the spleen, perhaps).
As you just stated there is no evidence of great vessel arteriitis. Of course you noticed the right aortic arch, but which type?
The first branch of the aorta is the left common carotid. Next is the right subclavian artery and the left common carotid. The last vessel is the aberrant left subclavian, retro-oesophagic in its course. It is a vascular ring.
Now we're talking great vessels - anything else that caught your eye?
There is left sided SVC, classically passing anterior to left main bronchus. It drains into a dilated coronary sinus - as it does in the great majority of cases - though not easily seen on the 3 mm slices provided.
Anything you would expect in patient history?
Congenital heart disease is a good guess, as both right aortic arch (at least some types) and left SVC have some association to congenital cardiac anomalies, with atrial and ventricle septal defects and tetralogy of Fallot on top of the list.
No acute abnormalities. No clear lymphadenopathy revealed. Spleen size near upper limit.
Right-sided aortic arch, vascular ring with aberrant left subclavian. Slight distension of upper third of oesophagus.
Left-sided SVC, draining into coronary sinus (though hard to appreciate on the 3mm slices provided).
Dilated right ventricle. Implantable loop recorder in subcutaneous tissue of left chest.
Syndesmophytes, ankylosis of vertebral column and SI joints. Arthritic changes in both hips.
Incidental note of sub-centimetre non-calcified nodule in right thyroid lobe and small fat-containing right-sided inguinal hernia.