A 65-year-old man is brought to the emergency department because of a 7-hour history of shortness of breath and chest pain. The pain started suddenly after he got out of bed in the morning and is worse on inspiration. Medical history is remarkable for type 2 diabetes mellitus complicated by diabetic nephropathy. The patient undergoes a 2-part nuclear medicine test. During the first part, he breathes in a radioactive tracer and a lung scan is performed. In the second part of the test, he is given an intravenous injection of a different radioactive material while breathing normal air, and the scan is repeated. When the images are compared, a large area of the lower right lung is not visualized in the second scan. Based on the observed findings, which of the following underlying disease processes is most likely present in this patient?

Question

A 65-year-old man is brought to the emergency department because of a 7-hour history of shortness of breath and chest pain. The pain started suddenly after he got out of bed in the morning and is worse on inspiration. Medical history is remarkable for type 2 diabetes mellitus complicated by diabetic nephropathy. The patient undergoes a 2-part nuclear medicine test.  During the first part, he breathes in a radioactive tracer and a lung scan is performed.  In the second part of the test, he is given an intravenous injection of a different radioactive material while breathing normal air, and the scan is repeated.  When the images are compared, a large area of the lower right lung is not visualized in the second scan.  Based on the observed findings, which of the following underlying disease processes is most likely present in this patient?

Quizplus · Accepted Answer

Eductional Objective: Ventilation-perfusion (V/Q) scans use radiotracers to compare the ventilation and blood perfusion of each area of the lung.  V/Q mismatch with perfusion defects are often indicative of a pulmonary embolism, which are most commonly caused by deep vein thrombosis in the lower extremities that embolizes to the pulmonary vasculature.

A 65-Year-Old Man Is Brought to the Emergency Department Because