Purpose: To compare the accuracy of three different magnetic resonance
angiography (MRA) techniques for studying steno-occlusive disease of
carotid arteries. Methods: 64 patients were evaluated with three MRA t
echniques- three-dimensional (3D) time-of-flight (TOF), two-dimensiona
l (2D) TOF, and 3D Phase-Contrast (PC); the acquisition was in the axi
al plane, the volume included the carotid bifurcation. Digital subtrac
tion angiography (DSA) was considered the 'gold standard'. The MRA ima
ges were reprojected with a maximum intensity pixel ray-tracing (MIP)
algorithm. The three MRA techniques were blindly graded as normal, mil
dly stenotic (0-29%), moderately stenotic (30-49%)T-severely stenotic
(70-99%), or occluded. Results: DSA provided 128 diagnostic judgments:
92 were negatives and 36 positives. 2D TOF was in agreement with angi
ography in 116 of 128 cases (90%), but overestimated the results in se
ven cases and underestimated in five cases. 3D TOF agreed with angiogr
aphy in 125 of 128 cases (97%), with one overestimation and two under
estimations. 3D PC was concordant in 116 of 128 cases (90%), overestim
ating in six cases, underestimating in six cases. The sensitivity, spe
cificity and diagnostic accuracy for 2D TOF was, respectively 84%, 94%
, and 92%, while for 3D TOF was 94%, 100%, and 98%, and for 3D PC 86%,
98%, and 95%. The comparison of the three different MRA techniques pr
ovided no statistically significant difference (Friedman test P < 0.05
). Conclusion: The high degree of diagnostic accuracy of MRA found in
the study of the steno-occlusive disease of the carotid arteries confi
rms the high degree of reliability of this methodology carried out wit
h the 3D TOF technique, compared to 2D TOF and 3D PC. (C) 1998 Elsevie
r Science Ireland Ltd. All rights reserved.