A technique called computed tomography venography (CTV) can help doctors identify blood clots in the legs that could break free and travel to the lungs and block an artery, a potentially deadly condition called pulmonary embolism, new research says.Blood clots in the legs (deep vein thrombosis) and pulmonary emobli are both signs of thromboembolic disease.A type of lung scan called CT pulmonary angiography (CTPA) is often used to find blood clots in the lungs. But CTPA can miss many clots in smaller arteries.A study in the February issue of Radiology found that using both CTV and CTPA increased the detection rate of thromboembolic disease by 20 percent.The study included 1,590 patients undergoing both procedures. CTPA detected pulmonary embolism in 15 percent of the patients and CTV detected deep vein thrombosis in 9 percent of the patients. Of those 148 patients, 100 had been diagnosed with pulmonary embolism by CTPA."Studies have shown that inadequately treated deep vein thrombosis is associated with recurring pulmonary emoboli,” study author Dr. Matthew D. Cham, a radiology resident at the University of Rochester School of Medicine and Dentistry, said in a prepared statement.Pulmonary embolism affects more than 600,000 people in the United States each year, and more than 60,000 of them die, according to the National Heart, Lung, and Blood Institute.