CTA negative means?

CTA negative means?

• A. CTA is positive for PE
• B. D-Dimer is unreliable
• C. CXR alone confirms PE
• D. PE is ruled out

Answer: (D)

A CT pulmonary angiography looks directly at the pulmonary arteries with contrast. If no filling defects are seen, there’s no visible embolus obstructing blood flow in the scanned vessels. Because CTA directly demonstrates the clot and has a high negative predictive value, a negative study effectively rules out pulmonary embolism for the current presentation. D-dimer results and chest radiographs don’t provide that level of direct evidence, so they don’t override a negative CTA. Be aware there are rare caveats—very small subsegmental emboli can occasionally be missed, or image quality can limit detection—but in routine practice, a negative CTA makes PE unlikely and guides you to explore other causes of the patient’s symptoms.

A CT pulmonary angiography looks directly at the pulmonary arteries with contrast. If no filling defects are seen, there’s no visible embolus obstructing blood flow in the scanned vessels. Because CTA directly demonstrates the clot and has a high negative predictive value, a negative study effectively rules out pulmonary embolism for the current presentation. D-dimer results and chest radiographs don’t provide that level of direct evidence, so they don’t override a negative CTA. Be aware there are rare caveats—very small subsegmental emboli can occasionally be missed, or image quality can limit detection—but in routine practice, a negative CTA makes PE unlikely and guides you to explore other causes of the patient’s symptoms.