Detection of arterial intimal lesions: an experimental study comparing ultrasonography and arteriography

A comparison between colour duplex ultrasonography and arteriography for imaging infrapopliteal arterial lesions

OBJECTIVE

To investigate the agreement between colour duplex ultrasonography and digital subtraction arteriography of the infrapopliteal arteries.

DESIGN

Retrospective, blinded study.

SETTING

Vascular laboratory and Radiology Department, University Hospital.

METHODS

The infrapopliteal vasculature was examined in a total of 51 limbs by both colour duplex ultrasound and digital subtraction angiography. By examining all arteries from the distal popliteal to the pedal arteries, a total of 204 individual arterial segments were available for analysis. Each segment was graded as 0-49%, 50-99% diameter reduced or occluded by both modalities. Using ultrasound, classification of stenoses was achieved by observing peak systolic velocity ratios; a doubling of peak systolic velocity indicating a > or = 50% diameter reducing stenosis. Where no Doppler signal could be obtained, the vessel was assumed to be occluded. From angiographic studies, two radiologists separately and blindly assessed the extent of disease for each infrapopliteal artery noting areas of > or = 50% diameter reduction and occlusion. The Kappa statistic was used to examine the level of agreement between angiography and ultrasound as well as between both radiologists.

RESULTS

The Kappa level (95% confidence interval) of agreement between ultrasound and angiographic assessments for distinguishing patent from occluded segments was 0.61 (0.49-0.74) for all segments. The equivalent agreement between radiologists was 0.80 (0.70-0.89). Poorest agreement was observed from ultrasound assessments of the peroneal and tibioperoneal trunk arterial segments.

CONCLUSION

Since agreement between colour duplex scanning and angiography never fell significantly below levels achieved between two radiologists, we conclude that colour duplex ultrasound can be used to assess infrapopliteal artery patency.

A prospective comparison of lower limb colour-coded Duplex scanning with arteriography

OBJECTIVE

To compare the diagnostic value of colour Duplex scanning with arteriography for the detection of arterial disease of the aortoiliac arteries, femoropopliteal arteries and the origins of the tibial vessels.

DESIGN

Prospective, semi-blind study.

SETTING

Vascular laboratory and radiology department, University Hospital.

METHODS

A total of 1658 arterial segments in 148 limbs were studied both by colour Duplex scanning and digital subtraction arteriography. Individual arterial segments were classified on the basis of peak systolic velocity ratios < 2.0, > or = 2.0 or an absent Doppler signal, as 0-49%, 50-99% diameter reduced, or occluded. The same arterial segments were similarly classified on the basis of arteriography and the two modalities were compared using a Kappa (k) analysis.

RESULTS

The overall agreement between arteriography and colour-coded Duplex was kappa = 0.74 (95% CI, 0.70-0.78), this indicates substantial agreement. Kappa values (95% CI) from the aortoiliac, femoropopliteal and the origins of the infrapopliteal arteries were kappa = 0.59 (0.49-0.73; moderate agreement), kappa = 0.80 (0.76-0.84; substantial agreement) and kappa = 0.48 (0.35-0.61; moderate agreement) respectively.

CONCLUSIONS

We conclude that there is substantial agreement between colour-coded Duplex and arteriography of the lower limbs, and that the ability of colour-coded Duplex to plan and guide lower limb vascular interventions requires investigation.