Gadolinium-enhanced magnetic resonance angiography for pulmonary embolism: a multicenter prospective study (PIOPED III).
BACKGROUND
The accuracy of gadolinium-enhanced magnetic resonance pulmonary angiography and magnetic resonance venography for diagnosing pulmonary embolism has not been determined conclusively.


OBJECTIVE
To investigate performance characteristics of magnetic resonance angiography, with or without magnetic resonance venography, for diagnosing pulmonary embolism.


METHODS
Prospective, multicenter study from 10 April 2006 to 30 September 2008.


METHODS
7 hospitals and their emergency services.


METHODS
371 adults with diagnosed or excluded pulmonary embolism.


METHODS
Sensitivity, specificity, and likelihood ratios were measured by comparing independently read magnetic resonance imaging with the reference standard for diagnosing pulmonary embolism. Reference standard diagnosis or exclusion was made by using various tests, including computed tomographic angiography and venography, ventilation-perfusion lung scan, venous ultrasonography, d-dimer assay, and clinical assessment.


RESULTS
Magnetic resonance angiography, averaged across centers, was technically inadequate in 25% of patients (92 of 371). The proportion of technically inadequate images ranged from 11% to 52% at various centers. Including patients with technically inadequate images, magnetic resonance angiography identified 57% (59 of 104) with pulmonary embolism. Technically adequate magnetic resonance angiography had a sensitivity of 78% and a specificity of 99%. Technically adequate magnetic resonance angiography and venography had a sensitivity of 92% and a specificity of 96%, but 52% of patients (194 of 370) had technically inadequate results.


CONCLUSIONS
A high proportion of patients with suspected embolism was not eligible or declined to participate.


CONCLUSIONS
Magnetic resonance pulmonary angiography should be considered only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated. Magnetic resonance pulmonary angiography and magnetic resonance venography combined have a higher sensitivity than magnetic resonance pulmonary angiography alone in patients with technically adequate images, but it is more difficult to obtain technically adequate images with the 2 procedures.
Stein
Paul D
PD
Michigan State University, College of Osteopathic Medicine, Department of Internal Medicine, Michigan State University Venous Thromboembolism Research Unit, St. Joseph-Mercy Oakland Hospital, 44405 Woodward Avenue, Pontiac, MI 48341-5023, USA. steinp@trinity-health.org
Chenevert
Thomas L
TL
Fowler
Sarah E
SE
Goodman
Lawrence R
LR
Gottschalk
Alexander
A
Hales
Charles A
CA
Hull
Russell D
RD
Jablonski
Kathleen A
KA
Leeper
Kenneth V
KV
Naidich
David P
DP
Sak
Daniel J
DJ
Sostman
H Dirk
HD
Tapson
Victor F
VF
Weg
John G
JG
Woodard
Pamela K
PK
D000328:Adult; D000368:Aged; D005260:Female; D005682:Gadolinium; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010690:Phlebography / Q000379:methods*; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012015:Reference Standards; D012680:Sensitivity and Specificity
D005682:Gadolinium