Changes

[[File:Central venous catheter with a fibrin sheathPAC met Gripper erin.jpgJPG|thumb|The fibrin sheath is indirectly seen in these images before and after radiocontrast infusion, as the radiocontrast collects around the catheterPort with needle assembly inserted.]]Fibrin sheaths of central venous catheters ports can be suspected when it is possible to infuse into it but not to aspirate.

Fibrin sheaths are usually detected by fluoroscopic catheter contrast angiography.<ref name="KnutstadHager2016">{{cite journal|last1=Knutstad|first1=K.|last2=Hager|first2=B.|last3=Hauser|first3=M.|title=Radiologic diagnosis and management of complications related to central venous access|journal=Acta Radiologica|volume=44|issue=5|year=2016|pages=508–516|issn=0284-1851|doi=10.1080/j.1600-0455.2003.00115.x}}</ref> Non ===Preparation===*Contrast should be non-ionic contrast , with a high iodine concentration (for example 300 mg/ml) is injected by hand using a .<ref name="KnutstadHager2016"/>*Syringe can be for example 10 ml or 20 ml, for injection by hand.<ref name="KnutstadHager2016"/> syringeFor pumps, the pressure should not exceed >40psi (275kPa or 2,75bar).<ref name=Helsingborg/>*The needle should be at least 20G (0. 9mm), and needs to be designed for port use (to avoid fragmentation of the port membrane).<ref name=Helsingborg>{{cite web|url=http://www.rontgen.com/metod/lungor-cvkport-a-cath|title=Porta-a-cath control|website=Röntgen Metodbok, Radiology Department of Helsingborg|accessdate=2018-07-25}}</ref>*The system needs to be closed to air at all times.<ref name=Helsingborg/> The total amount of contrast is rather small (5-15ml) so a decreased renal function does not need to to be a contraindication.<ref name=Helsingborg/> ==Image taking==A precontrast view is followed by a series of images during contrast infusion, at a small field-of-view.<ref name="KnutstadHager2016"/> It can be done at 2-4 images per second,<ref name="KnutstadHager2016"/> but also up to 15 images per second and a short exposure time of 3-4 seconds. After the procedure, the system should be flushed with 20 - 30 ml normal saline.<ref name=Helsingborg/>