What type of imaging study is best for diagnosing pulmonary embolism (PE)?

The most effective imaging study for diagnosing pulmonary embolism (PE) is a helical CT, also known as CT pulmonary angiography. This technique provides detailed images of the pulmonary arteries and allows for the identification of blood clots within them. The rapid acquisition of image slices during the helical CT scan, combined with the use of contrast material, enhances visualization of the vascular structures, making it the gold standard for detecting PE.

X-rays can be useful in ruling out other conditions related to chest pain or shortness of breath, but they are not sensitive or specific enough for diagnosing PE. MRI is typically not used for this purpose due to availability, prolonged examination times, and limited accessibility compared to CT. Ultrasound may be beneficial in identifying deep vein thrombosis (DVT), which is a common source of emboli leading to PE, but it does not directly visualizes the lungs or the pulmonary arteries where emboli would be located. Therefore, helical CT is the preferred method for directly diagnosing pulmonary embolism.