Exposition aux rayonnements : est-il possible d'éviter la dose délivrée aux patients lors de l'examen par IRM des embolies pulmonaires en développant de nouvelles stratégies?


Josephine Pressacco

Institut de cardiologie de Montréal


Domaine : services de santé

Programme recherches en radiologie

Concours 2012-2013


Fondation de l'Association des radiologistes du Québec

Pulmonary embolism (PE) occurs when a blood clot dislodges from a vein in the body and travels via the bloodstream to the lung. It causes blockage in an artery, thus preventing oxygen from reaching other organs in the body. PE can be deadly if not identified and treated promptly. When the doctor suspects PE, tests are ordered to confirm the diagnosis. The most commonly ordered test is computed tomography (CT) because it is accurate and painless.

Computed tomography is well tolerated, but there are certain risks associated with this exam. The CT scanner rotates around the body, taking multiple xrays and thus exposing the patient to ionizing radiation. The amount of ionizing radiation given off by a CT of the chest is equivalent to more than 100 chest xrays. Exposure to ionizing radiation can ultimately lead to cancer. Although the chance of getting cancer from a single CT exam is relatively small, it is thought that for a thirty-year-old woman, for example, the risk of cancer is 1 in 1,000 after having a single CT.

An alternative imaging exam called magnetic resonance imaging (MRI) uses a strong magnet and radio waves to obtain pictures of the inside of the body. Magnetic resonance imaging poses no cancer risk because it does not use ionizing radiation.

The goal of this project is to develop an MRI exam that can produce images as accurate and informative as those provided by CT in order to determine whether it could be used as an alternative to CT in the diagnosis of PE. The successful development of such an exam would mean that patients could be spared exposure to ionizing radiation and the increased risk of cancer without sacrificing accuracy of diagnosis.