==Evaluation==
[[File:{{Central venous catheter with a fibrin sheath.jpg|thumb|The fibrin sheath is indirectly seen tip position in these images before X-ray and after radiocontrast infusion, as the radiocontrast collects around the catheter.]]fluoroscopy}} ===Fibrin sheath===
In a normal case, the contrast flows straight out from the catheter.<ref name=Helsingborg/> Contrast flowing at a skewed angle compared to the catheter means a suspected fibrin sheath.<ref name=Helsingborg/>
A definite fibrin sheath is visualized as contrast flowing backwards around the catheter, looking like a thickening of the distal part, before exiting at a more proximal part of the catheter.
[[File:Central venous catheter with a fibrin sheath.jpg|thumb|center|The fibrin sheath is indirectly seen in these images before and after radiocontrast infusion, as the radiocontrast collects around the catheter.]]
==Report==