Researchers now say an indirect CT venography ( CTV ) could identify blood clots in the legs that have the potential to break free, travel to the lung, and block an artery a life-threatening condition known as pulmonary embolism as smaller arteries are not visible in a commonly used lung scan, CT pulmonary angiography (CTPA), which is used to detect the presence of these blood clots in the lung.
Researchers studied 1,590 patients undergoing both CTPA and CTV. CTPA detected pulmonary embolism in 15 percent, or 243 patients; CTV deep vein thrombosis revealed in 148 or 9 percent of patients. Of those 148 patients, only 100 had been diagnosed with pulmonary embolism by CTPA. Performing CTV in addition to CTPA was found to increase the detection rate of thromboembolic disease by 20 percent.
In conclusion researchers say combining CTV and CTPA eliminates the need for a separate lower extremity examination that can further delay diagnosis.