Volume rendering compared with maximum intensity projection for magnetic resonance angiography measurements of the abdominal aorta.
OBJECTIVE
To compare the volume rendering technique (VRT) with maximum intensity projection (MIP) for aortic diameter measurements in MR angiography (MRA) data sets.


METHODS
Existing contrast-enhanced 3-dimensional MRA and digital subtraction angiography (DSA) data sets from 20 patients were analyzed. In each MRA data set, two aortic diameters were measured using MIP and VRT. Agreement with DSA measurements, dependence on rendering parameters, and interobserver agreement were assessed.


RESULTS
Diameters measured on MIP with fixed parameters showed no significant difference compared with DSA and with freely selected parameters a slight overestimation relative to DSA. Diameters measured on VRT were larger than on DSA. For both MIP and VRT, the measurements depended on the chosen parameters. The error relative to DSA was larger for VRT than for MIP with fixed parameters but not with freely chosen parameters. Interobserver agreement did not differ significantly.


CONCLUSIONS
VRT is not suitable for diameter measurements of the abdominal aorta with fixed parameter settings but may be useful with user-selected settings.
Persson
A
A
Department of Radiology, Center for Medical Image Science and Visualization, Linköping University Hospital, Sweden. anders.persson@cmiv.liu.se
Dahlström
N
N
Engellau
L
L
Larsson
E M
EM
Brismar
T B
TB
Smedby
O
O
D000368:Aged; D000704:Analysis of Variance; D015901:Angiography, Digital Subtraction / Q000706:statistics & numerical data; D001012:Aorta, Abdominal / Q000473:pathology*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015588:Observer Variation; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology
D003287:Contrast Media