Mark L. Schiebler MD, Presenter: Advisory Board, Koninklijke Philips Electronics NV Advisory Board, General Electric Company

Scott K. Nagle MD, PhD, Abstract Co-Author: Stockholder, General Electric Company

Christopher Jean-Pierre Francois MD, Abstract Co-Author: Research agreement, General Electric Company

Thomas Martin Grist MD, Abstract Co-Author: Speaker, General Electric Company Advisory Board, Bayer AG Consultant, Bracco Group Speaker, Bracco Group

Michael D Repplinger MD, Abstract Co-Author: Nothing to Disclose

Jean Helen Brittain PhD, Abstract Co-Author: Employee, General Electric Company

Reed F. Busse PhD, Abstract Co-Author: Employee, General Electric Company

Anja C. S. Brau PhD, Abstract Co-Author: Employee, General Electric Company

Scott Brian Reeder MD, PhD, Abstract Co-Author: Spouse, employee, General Electric Company Medical Advisory Board, General Electric Company

To retrospectively evaluate the clinical utility of a high resolution contrast-enhanced 3D pulmonary MRA with 2D parallel imaging for the evaluation of pulmonary embolism in symptomatic patients.

 This was a HIPAA-compliant IRB-approved retrospective review of 89 consecutive patients referred for pulmonary MRA for suspected pulmonary embolism. The protocol utilized auto-calibrated parallel imaging (2D ARC) with sagittal slab excitation to obtain 1.3 x 1.8 x 2.0 mm resolution in a 14-19s breath-hold. Total time on the table was 5-6 min, similar to CTA. Review of final MRI report was performed for all cases for the determination of whether or not the initial read was positive or negative for pulmonary embolism. Chart review for all 89 patients was performed to look for evidence of thromboembolic disease within 6 months following the MRA exam. This was used as a surrogate for the confirmation of all negative studies. All CTA Chest exams within a 10 day time period were compared to the pulmonary MRA’s performed to evaluate for any discrepancies.

All patients successfully completed the MRA examination. Pulmonary emboli were found in a total of 8/89 (9%) patients. One case (1/89, 1%) was equivocal and one case (1/89, 1%) was non-diagnostic due to respiratory motion. Review of medical records showed no evidence of new thromboembolic disease in all negative MRA cases at 6 months of follow-up. There were problems with determining  the sub-segmental vessels  in  the right middle lobe and lingular segments which showed blurring in 45/89 (51%), likely related to cardiac motion. There were a total of 14 Chest CTA’s available for comparison within 10 days of the MRA. There were no discrepancies in the results. Due to poor contrast bolus on  4 of the CTA’s, the pulmonary MRA’s were of higher quality and served as the diagnostic exam of record for those patients.

Image quality using this pulmonary MRA protocol was diagnostic in all but one exam with complete chest coverage, high spatial resolution and short scan time, resulting in its adoption by our emergency department physicians as the study of choice for evaluating young patients for pulmonary embolism.

The use of Pulmonary MRA is a promising choice for a “no radiation dose" imaging test to exclude the presence pulmonary embolism in a vulnerable population (young women and children).

Schiebler, M, Nagle, S, Francois, C, Grist, T, Repplinger, M, Brittain, J, Busse, R, Brau, A, Reeder, S, Clinical Implementation of High Resolution 3D Contrast-enhanced Pulmonary MRA with Full Chest Coverage Using 2D Parallel Imaging in Symptomatic Patients.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008320.html