Evaluation of intraportal venous flow distribution by unenhanced MR angiography using three-dimensional fast spin-echo with a selective tagging pulse: efficacy of subtraction of tag-on and tag-off images acquired during a single breath-hold.
OBJECTIVE
To evaluate the efficacy of subtracted MR images from two sets of unenhanced three-dimensional (3D) MR angiography data (tag-on and tag-off images) acquired simultaneously during a single breath-hold in assessing the intraportal venous flow distribution to the distal branches from the superior mesenteric vein (SMV) and the splenic vein (SpV).


METHODS
Tag-on and tag-off MR images during a single breath-hold were obtained in 25 normal subjects. Tagging pulse was placed on the SMV or SpV separately to study inflow correlation of tagged blood into the portal vein.


RESULTS
On the MR images tagged on the SMV, the mean ratings of visibility of tagged blood flow on the subtracted images were significantly higher (P = 0.016-0.0001) than those on the source images in almost all branches except second-ordered left portal vein (P = 0.096). On the subtracted MR images tagged on SMV, the tramline (16 of the 25 subjects) was the most common distribution pattern of the tagged blood inflow in the main portal vein.


CONCLUSIONS
Subtracted MR images from two sets of unenhanced 3D MR angiography data (tag-on and tag-off images) acquired simultaneously would be effective to show the blood flow distribution of tagged blood into the portal vein and distal branches from SMV and SpV under the physiological condition without contrast injections.
Ito
Katsuyoshi
K
Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan. itokatsu@med.kawasaki-m.ac.jp
Shimizu
Ayame
A
Tsukuda
Toshinobu
T
Sasaki
Katsumi
K
Tanabe
Masahiro
M
Matsunaga
Naofumi
N
Jo
Chisaki
C
Kanazawa
Hitoshi
H
Miyazaki
Mitsue
M
D000328:Adult; D000465:Algorithms; D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000033:anatomy & histology* / Q000502:physiology*; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D013113:Spin Labels; D013382:Subtraction Technique
D013113:Spin Labels