Abstract
Introduction Disruption to contrast agent supply chains for radiology investigations has become an additional consequence of the COVID-19 pandemic. Various protocols have been developed to account for this limited availability.
Case An 80-year-old male, previously independent, presented with confusion, reduced level of consciousness, headache and vomiting. On exam he was drowsy, febrile and haemodynamically stable. He had bilateral proptosis and chemosis with complex ophthalmoplegia. Neurological examination was otherwise unremarkable.
A CT venogram using an ‘Ultravist 300’ (iopromide) contrast agent demonstrated complete opacification of the right sphenoid sinus, mild bilateral proptosis and asymmetry of the superior ophthalmic veins. Cavernous sinus abnormalities were not easily appreciated, and so a repeat CT venogram was sought; an Magnetic Resonance (MR) venogram was not readily available. An ‘Omnipaque 350’ (iohexol) contrast agent was used for the second scan, which demonstrated features suggestive of occlusive thrombosis of the bilateral superior ophthalmic veins, bilateral cavernous sinuses and right superior petrosal sinus. Further investigations resulted in the diagnosis of a septic venous thrombosis, provoked in the setting of a complicated sinusitis.
Conclusion Interestingly, two separate CT venograms with different contrast agents, undertaken on the same day for the same patient, yielded different results. The presence of other variables precludes the ability to comment on the superiority of either agent. The case exemplifies the notion that diagnostic imaging should always be guided by a detailed history and examination and also raises the discussion point of whether more strict or uniform protocols for contrast should be developed for radiology investigations.
