Home » 2009 » Number 09-19: Pulmonary embolism by CMR

Number 09-19: Pulmonary Embolism by CMR

Case from: Andrei Samarin, MD^{1, 2}, Roger Shifrin, MD², Carsten Schmalfuss MD², Gary Cooper MD²
North Estonia Medical Centre, Tallinn, Estonia^{1, 2} & Departments of Radiology and Medicine, University of Florida², Gainesville, Florida, US

Clinical history: A 34-year-old white female with a history of anxiety, mild asthma, and allergic rhinitis was recently hospitalized with an episode of SVT.  She was not taking any medications, except for oral contraceptives.
She is a nursing student and had just finished inserting an IV when she suddenly developed palpitations with severe diaphoresis, dizziness, lightheadedness, and pre-syncope. Physical examination showed increased body mass index but was otherwise normal.  Six weeks later she was referred for CMR because of a concern for ARVD.
Initial 12 lead ECG and trans-thoracic echocardiogram were normal.

Image 1

Image 2

The initial axial (Image 1) and coronal (Image 2) SSFP localizer aised the suspicion of a saddle embolus (white arrow) at the RPA/LPA bifurcation.
Inital review of these images allowed subsequent planning of CMR scan protocol in order to establish or confirm this diagnostic suspicion.

Movie 1

Movie 2

CMR Findings: There is mild right ventricular dilation, a flattened "D" shaped inter-ventricular septum, and septal bounce all of which are consistent with increased right heart pressures (Movie 1). A saddle embolus is present with smaller emboli in the right and left branch pulmonary arteries (Movie 2).  

Image 3

Chest CT: axial contrast enhanced images (Image 3) demonstrated the saddle embolus (black arrow) and confirmed the diagnosis.

A coagulopathy was then excluded and the only causative factor for embolism seemed to be oral contraceptives.

Perspective: In patients with otherwise unexplained elevation of right heart pressures undergoing CMR, the pulmonary arteries should be carefully examined for evidence of emboli. In this setting, CMR bright blood imaging is a useful technique to assess the main PA, and the origin and proximal segments of the RPA and LPA. However, only contrast enhanced MRA can image the full pulmonary tree, including the distal branches.

References

1. Jahnke C, Kaufmann J, Stauber B, Goetze S, Fleck E, Paetsch I. Magnetic resonance imaging for monitoring the efficacy of thrombolytic therapy in subacute pulmonary artery embolism. J Am Coll Cardiol 2009;54:1335. 

 2. Altun E, Heredia V, Pamuklar E, Zapparoli M, Semelka RC. Feasibility of post-gadolinium three-dimensional gradient-echo sequence to evaluate the pulmonary arterial vasculature. Magn Reson Imaging 2009;27:1198-207.

3. Miserus RJ, Herias MV, Prinzen L, Lobbes MB, Van Suylen RJ, Dirksen A, Hackeng TM, Heemskerk JW, van Engelshoven JM, Daemen MJ, van Zandvoort MA, Heeneman S, Kooi ME. Molecular MRI of early thrombus formation using a bimodal alpha2-antiplasmin-based contrast agent. JACC Cardiovasc Imaging 2009;2:987-96.

Submit your case here

COTW handling editor: Chiara Bucciarelli-Ducci