COMPARISON OF ULTRASOUND AND BLOOD-POOL SCINTIGRAPHY IN THE DIAGNOSISOF LOWER-LIMB DEEP VENOUS THROMBOSIS

We report a prospective, blinded comparison of compression ultrasound (US) and Tc-99m erythrocyte-labelled venous blood pool scintigraphy (B PS) in patients presenting with symptoms of deep venous thrombosis (DV T). Contrast venography (CV) was used as the gold standard. Ninety-eig ht lower limbs of 76 patients were examined. DVT was present at CV in 38 of 98 limbs and was isolated to the calf veins in eight. Sensitivit y and specificity of ultrasound for femoropopliteal thrombus were 81.5 % and 96% and of venous blood pool scintigraphy were 55% and 96%. For deep venous thrombosis in the whole limb sensitivity and specificity o f ultrasound were 74% and 90% and of venous blood pool scintigraphy we re 61% and 88%. In the calf sensitivity and specificity of US were 61% and 94% and of venous blood pool scintigraphy were 61% and 89%. Exclu ding equivocal venous blood pool scintigraphy results, the predictive values of a positive and negative venous blood pool scintigraphy study for the whole limb were 84% and 86%. The predictive values of a posit ive and negative ultrasound where the examination was adequate were 82 % and 86%. US is a more sensitive alternative to CV than BPS for femor opopliteal DVT. When neither US nor CV can be performed, BPS remains a useful initial test for DVT, provided it is unequivocally positive or negative.