Author/Editor		Berden, Pavel
Title		Magnetic resonance angiography of the portal venous system
Translated title		Magnetnoresonančna angiografija splenoportalnega sistema
Type		članek
Source		Radiol Oncol
Vol. and No.		Letnik 38, št. 4
Publication year		2004
Volume		str. 291-7
Language		eng
Abstract		Background. Imaging of the portal venous system is necessary in different clinical conditions. Three-dimensional (3D) contrast-enhanced magnetic resonance angiography (MRA) is useful in obtaining high quality portal vein images. A fast gradient-echo MR imaging sequence with minimum repetition time and echo time is used. Up to 40 ml of paramagnetic contrast is injected into peripheral vein as a bolus. The Arrival of contrast medium in the aorta is preferably detected with an automated system, when breath-hold sequence is started, and repeated two times, to depict arterial and venous phase. Maximum-intensity-projection (MIP) imaging is the usual postprocessing method. Conclusions. In patients with portal hypertension, MRA can present collateral pathway and patency of the portal vein or portosystemic shunt. In portal vein thrombosis MRA provides information about the location and length of portal vein obstruction and helps in therapeutic strategy decision. MRA is a proper technique in Budd-Chiari syndrome, where it is important to determine the location and length of hepatie outflow obstruction. MRA is a very good modality before liver transplantation to depict vascular anatomy and portal vein patency, and after liver transplantation to image possible liver complications. Its limitations include inappropriate positioning of the 3D acquisition slab, respiratory motion artefacts, and metal implants (e.g. pacemaker).
Summary		Izhodišča. Splenoportalni venski sistem moramo prikazati pri različnih kliničnih stanjih. Tridimenzionalna (3D) magnetnoresonančna angiografija (MRA) s kontrastom splenoportalni sistem dobro prikaže. Uporabljamo hitre sekvence z gradientnim odmevom ter najkrajšim možnim časom ponovitve in odmeva. Skozi periferno veno injiciramo do 40 ml paramagnetnega kontrastnega sredstva. Za zaznavanje kontrasta v aorti je najbolje uporabiti avtomatiziran sistem, ki nato tudi sproži slikanje. Slikanje opravimo v zadržanem dihu in dvakrat ponovimo, da prikažemo arterijsko in vensko fazo. Za obdelavo slik po preiskavi največkrat uporabljamo tehniko projekcije maksimalne intenzitete (MIP). Zaključki. Pri bolnikih s portalno hipertenzijo MRA dobro prikaže kolaterale ter prehodnost portalne vene ali portosistemskega šanta. MRA pokaže mesto in dolžino zapore portalne vene pri trombozi portalne vene in pomaga pri odločitvi o načinu zdravljenja. Je ustrezna tehnika pri sindromu Budd-Chiari, kjer je pomembno določiti mesto in dolžino zapore jetrnih ven. MRA je zelo dobra metoda pred presaditvijo jeter, saj odlično prikaže anatomijo in prehodnost portalne vene, in tudi po presaditvi za odkrivanje morebitnih zapletov. Omejitev MRA predstavljajo metalni vsadki (npr. srčni vzpodbujevalnik), nezadovoljiv prikaz pa lahko dobimo pri nepravilni nastavitvi področja slikanja in premikanju zaradi dihanja.
Descriptors		PORTAL VEIN MAGNETIC RESONANCE ANGIOGRAPHY HYPERTENSION, PORTAL VASCULAR PATENCY HEPATIC VEIN THROMBOSIS LIVER TRANSPLANTATION PORTASYSTEMIC SHUNT, SURGICAL