title: MRI for short-term follow-up of acute pulmonary embolism. Assessment of thrombus appearance and pulmonary perfusion: a feasibility study.
abstract: Tha aim of this study was to demonstrate the feasibility of MRI for short-term follow-up examinations in patients with acute pulmonary embolism (PE), and to assess temporal changes of pulmonary perfusion and thrombus characteristics that may be helpful in determining thrombus age. Thirty-three patients (15 female, 18 male, mean age 59.4 years) with acute PE were examined initially and 1 week later using both 16-row computed tomography (CT) and MRI with magnetic resonance angiography (MRA), real-time MRI and magnetic resonance (MR) pulmonary perfusion imaging. MRA and MR pulmonary perfusion used contrast-enhanced 3D flash sequences, and real-time MRI used true fast imaging with steady-state precession sequences (repetition time/echo time 3.1/1.5, bandwidth 975 Hz, 256 matrix size, acquisition time 0.4 s per image) in three orthogonal planes. Follow-up examinations were feasible for all patients. Diagnosis of PE was concordant between MRI and CT in all patients. The signal intensity of embolic material increased after 1 week for real-time MRI [132+/-5 vs. 232+/-22 (standard error of the mean), p<0.001], but not significantly for MRA. MR pulmonary perfusion of areas affected by PE increased (area under the curve initially 9.6+/-7.4, at follow-up 40.7+/-7.6, p<0.001). A decreasing time-to-peak in normal lung areas (15.7+/-0.96 and 13.2+/-0.55, respectively, p<0.05) indicated systemic circulatory effects of PE, and subsiding pulmonary artery obstruction improved arterial inflow for the entire lung. Follow-up examinations of patients with acute PE are feasible with MRI, and a relation between thrombus appearance and thrombus age can be implied.
authors.affiliation: Department of Diagnostic Radiology, Kerckhoff Heart Center, Benekestrasse 2-8, 61231 Bad Nauheim, Germany. a.kluge@kerckhoff-klinik.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Kluge
authors.forename: Tibo
authors.initials: T
authors.lastname: Gerriets
authors.forename: Uwe
authors.initials: U
authors.lastname: Lange
authors.forename: George
authors.initials: G
authors.lastname: Bachman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D011652:Pulmonary Circulation / Q000502:physiology*; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA