COLOR DUPLEX VERSUS CT ANGIOGRAPHY IN ASSESSMENT OF INFRA POPLITEAL ARTERIAL CIRCULATION IN DIABETIC PATIENTS: A COMPARATIVE STUDY

Abstract

Background: Peripheral vascular disease is narrowing or occlusion of arteries mostly due to atherosclerosis which is very common in patients with diabetes mellitus (DM). Objective: To compare lower limb arterial diseases using Color duplex and multi-detector CT angiography (MDCTA) and to find the better non-invasive modality of choice. Patients and Methods: Thirty diabetic patients of lower limb peripheral arterial disease underwent Color duplex and multi-detector CT angiography (MDCTA). Infra popliteal arterial system, divided into anatomic segments and luminal narrowing, were compared using color duplex and axial images of arterial phase of CT angiography. Using statistical methods, sensitivity, specificity and accuracy of color duplex and CT angiography were determined. Results: One hundred and fifty six arterial segments were studied with CT angiography and color duplex. Out of the total 156 vessel segments, color duplex was able to detect 140 (89.7 %) diseased segments, while MDCTA which was able to detect 114 (73 %) diseased segments. Color duplex was able to pick up grade 1 lesions better than MDCT angiography with sensitivity 91.6%. Grade 2 and grade 3 were better picked up by MDCT angiography with color duplex sensitivity of 80% and 76 % for grade 2 and grade 3 respectively. The two modalities showed comparable results for grade 4 lesions with sensitivity of 85.7 %. Significant statistical agreement existed between color duplex and CT angiography with moderate total agreement (Weighted kappa estimation (Kw) = 0.64) for grade 1 lesions, fair total agreement (Kw= 0.39) for grade 2 lesions, good total agreement (Kw = 0.75) for grade 3 and very good agreement (Kw= 0.88) for grade 4 lesions. Conclusion: Color duplex is a safe, inexpensive, non-invasive, easily available diagnostic tool with high diagnostic accuracy in the investigation of peripheral arterial disease PAD among patients with diabetes mellitus DM. Color duplex is better than CT angiography in the diagnosis of Grade 1 and 2 lesions. CT angiography is more accurate in assessing grade 3 and grade 4 stenosis. Color duplex remains the only available diagnostic tool in diabetic patients with contraindications for contrast media administration.