High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues.
BACKGROUND
In biomedical sciences, ex vivo angiography is a practical mean to elucidate vascular structures three-dimensionally with simultaneous estimation of intravascular volume. The objectives of this study were to develop a magnetic resonance (MR) method for ex vivo angiography and to compare the findings with computed tomography (CT). To demonstrate the usefulness of this method, examples are provided from four different tissues and species: the human placenta, a rice field eel, a porcine heart and a turtle.


RESULTS
The optimal solution for ex vivo MR angiography (MRA) was a compound containing gelatine (0.05 g/mL), the CT contrast agent barium sulphate (0.43 mol/L) and the MR contrast agent gadoteric acid (2.5 mmol/L). It was possible to perform angiography on all specimens. We found that ex vivo MRA could only be performed on fresh tissue because formalin fixation makes the blood vessels permeable to the MR contrast agent.


CONCLUSIONS
Ex vivo MRA provides high-resolution images of fresh tissue and delineates fine structures that we were unable to visualise by CT. We found that MRA provided detailed information similar to or better than conventional CTA in its ability to visualize vessel configuration while avoiding interfering signals from adjacent bones. Interestingly, we found that vascular tissue becomes leaky when formalin-fixed, leading to increased permeability and extravascular leakage of MR contrast agent.
MR-research Centre, Aarhus University Hospital, Aarhus, Denmark.
Anne S
AS
Rasmussen
Henrik
H
Lauridsen
Christoffer
C
Laustsen
Bjarke G
BG
Jensen
Steen F
SF
Pedersen
Lars
L
Uhrenholt
Lene W T
LW
Boel
Niels
N
Uldbjerg
Tobias
T
Wang
Michael
M
Pedersen
D000818:Animals; D003287:Contrast Media; D017023:Coronary Angiography; D005260:Female; D006321:Heart; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D010920:Placenta; D011247:Pregnancy; D013552:Swine
D003287:Contrast Media