SUSPECTED PULMONARY-EMBOLISM - PROSPECTIVE EVALUATION WITH PULMONARY MR-ANGIOGRAPHY

PURPOSE: To prospectively evaluate three magnetic resonance (MR) imagi ng techniques for detection of pulmonary embolism. MATERIALS AND METHO DS: Eighteen patients in whom the presence of acute or chronic pulmona ry emboli was suspected underwent examination with the following pulse sequences: cardiac-gated spin echo, cine spatial modulation of magnet ization, and two-dimensional time-of-flight pulmonary breath-hold (PBH ) MR angiography. Three radiologists independently and blindly reviewe d each case and graded a total of 518 arterial segments for each pulse sequence with a continuous scale of 0%-100% for likelihood of pulmona ry embolism. RESULTS: The overall sensitivity of PBH MR angiography fo r detection of acute pulmonary emboli was 0.85; for chronic emboli, wh ich were smaller in anteroposterior (AP) diameter, the overall sensiti vity was 0.42. Emboli larger than 1 cm in AP diameter were typically i dentified with >75% confidence with all pulse sequences. CONCLUSION: A cute pulmonary emboli greater than 1 cm in AP diameter were as accurat ely identified on PBH MR angiograms obtained in 15 seconds as they wer e on MR images obtained with longer pulse sequences not dependent on b reath holding.