MRI of pregnant patients for suspected pulmonary embolism: steady-state free precession vs postgadolinium 3D-GRE.

INTRODUCTION: Pulmonary embolism is a leading cause of maternal mortality in the developed world. Ventilation-perfusion scintigraphy and Computer tomography cause ionizing radiation exposure. Gadolinium-enhanced magnetic resonance imaging is generally not indicated in pregnant patients. MRI using motion resistant techniques that do not use intravenous contrast material, such as balanced steady-state free precession may be a better approach in pregnant patients.
PURPOSE: To describe the preliminary findings of the use of SSFP for the evaluation of pregnant patients with suspected PE, and to compare with a young women population evaluated with postgadolinium 3D-gradient echo sequences for the same intention.
MATERIALS AND METHODS: Radiology database was searched for two groups of subjects who underwent chest MRI at 1.5T for suspected PE, between January, 2007 and June, 2010: pregnant patients with MRI including balanced SSFP (group A) and females younger than 45 years old including a T1-weighted postgadolinium 3D-GRE (group B) sequence. The final study population consisted of 21 subjects. Blind and independent evaluation of MR images was performed for image quality of the pulmonary arterial system, PE and other chest findings. Data was subject to statistical analysis.
RESULTS: Good image quality was observed in all central and lobar arteries on both groups and in 90% (group A) and at least 83.3% (group B) of the segmental arteries. There was no significant difference between groups A and B for image quality of central and lobar pulmonary arteries (p > 0.05).
CONCLUSION: SSFP can visualize central, lobar and segmental pulmonary arteries with sufficient image quality in pregnant patients, comparable to 3D-GRE.