MR angiography in carotid stenosis: a comparison of three techniques.
OBJECTIVE
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 techniques- three-dimensional (3D) time-of-flight (TOF), two-dimensional (2D) TOF, and 3D Phase-Contrast (PC); the acquisition was in the axial plane, the volume included the carotid bifurcation. Digital subtraction angiography (DSA) was considered the 'gold standard'. The MRA images were reprojected with a maximum intensity pixel ray-tracing (MIP) algorithm. The three MRA techniques were blindly graded as normal, mildly stenotic (0-29%), moderately stenotic (30-49%), severely stenotic (70-99%), or occluded.


RESULTS
DSA provided 128 diagnostic judgments: 92 were negatives and 36 positives. 2D TOF was in agreement with angiography in 116 of 128 cases (90%), but overestimated the results in seven cases and underestimated in five cases. 3D TOF agreed with angiography in 125 of 128 cases (97%), with one overestimation and two under estimations. 3D PC was concordant in 116 of 128 cases (90%), overestimating in six cases, underestimating in six cases. The sensitivity, specificity 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 provided no statistically significant difference (Friedman test P < 0.05).


CONCLUSIONS
The high degree of diagnostic accuracy of MRA found in the study of the steno-occlusive disease of the carotid arteries confirms the high degree of reliability of this methodology carried out with the 3D TOF technique, compared to 2D TOF and 3D PC.
Scarabino
T
T
Department of Radiology, Scientific Institute Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy.
Carriero
A
A
Magarelli
N
N
Florio
F
F
Giannatempo
G M
GM
Bonomo
L
L
Salvolini
U
U
D002339:Carotid Arteries / Q000473:pathology; D016893:Carotid Stenosis / Q000175:diagnosis*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D012680:Sensitivity and Specificity