Aims and objectives
In the majority of reports on the endovascular management of May Thurner syndrome,
measurements have been performed in axial computed tomography (CT) images.
However,
area measurement obtained by intravascular ultrasound (IVUS) is considered in current practice the gold standard for assessing these lesions.
Furthermore,
there is increasing awareness that due to the irregular shape of veins,
especially when compressed,
diameter measurements are less accurate than area measurements.
The debate regarding the definition of a significant iliofemoral vein stenosis is ongoing.
Any attempt to treat obstruction...
Methods and materials
This was a retrospective study that included the first 50 consecutive outpatients with evidence of May-Thurner syndrome in prescheduled abdominal contrast-enhanced CTs,
performed for reasons unrelated to venous disease.
Patients with history of deep venous thrombosis were excluded.
Three measurement techniques were employed: 1) diameter measurement in axial CT images 2) diameter measurement in multiplanar reconstructions (MPR) orthogonal to the line of blood flow 3) manual measurement of the cross-sectional area in reconstructions orthogonal to the line of blood flow.
The percentage of compression of...
Results
ANOVA showed statistically significant differences among the three methods of assessment (F=121.7,
p<0.001).
More specifically,
mean degree of stenosis assessed by axial imaging (54.8+/- 12.9%) was significantly higher compared to mean degree of stenosis assessed by area (20.2+/-14.2%); p<0.001.
Similarly,
mean degree of stenosis assessed by MPR (51.5+/-9.1%) was also higher than mean degree of stenosis assessed by area (p<0.001).
No statistically significant difference was found between mean degree of stenosis assessed by axial imaging and MPR (p=0.54).
Conclusion
Diameter measurements in CT scans for assessment of May Thurner syndrome tend to overestimate stenosis when compared to area measurements.
Area measurements in reconstructions orthogonal to the line of blood flow may provide a more accurate method of assessing these lesions and should be validated against other methods,
such as IVUS.
Based on our findings,
the use of diameter measurements as a method of assessing iliac venous lesions should be reconsidered.
References
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