Diagnostic Accuracy of Color Doppler in Peripheral Artery Occlusive Disease

Abstract

Background: Doppler ultrasonography enables high resolution imaging of the peripheral arteries with precise anatomical and physiological information. It may also determine the significance of equivocal lesions of peripheral arterial occlusive disease (PAD) identified by computed tomography (CT) angiography. A combination of duplex ultrasonography (USG) with CT angiography has better diagnostic accuracy.The rationale behind conducting the study is to determine whether duplex USG is a reliable modality for the evaluation of arterial occlusive disease of lower extremity compared to CT angiography. Aim: This prospective study aims to determine the accuracy of Duplex Ultrasound compared with CT angiography in identifying and estimating the degree of obstructive arterial lesions in lower limbs. Method: The decision to image is reserved to those patients in whom suitable lesions for intervention can be identified; these include those patients with pain at rest, trophic changes, and a few patients with intermittent claudication. Vascular segments were analyzed independently for the presence of hemodynamically significant stenosis or occlusion. Sensitivity, specificity, positive predictive value and negative predictive value of DUS against CTA were obtained. Forty one patients (32 men, 9 women) were subjected to the study. Of these patients, four patients had below knee amputation. Through 82 limbs, 760 individual arterial segments were evaluated using each modality. Conclusion: When extensive calcifications are present in the vessel, the end product of CT angiography is of questionable diagnostic value as it overstages the lesion. Doppler is able to demonstrate this overstaging of CT by showing that the calcific plaque which appears to have produced more than 50% stenosis has actually not resulted in hemodynamically significant stenosis. Doppler is able to demonstrate dampened monophasic flow in those infrapopliteal vessels where CT shows poor distal runoff opacification with contrast due to proximal significant stenosis. Doppler is also able to demonstrate the nature of plaque – whether calcific or soft plaque. Soft plaques were better demonstrated with ultrasound than with CT. DUS duplex USG is preeminent in the investigation of peripheral arterial disease for being a noninvasive, easily available inexpensive, and safe diagnostic tool with high diagnostic accuracy.

Keywords

• doppler
• pad
• peripheral