MR-IMAGING WITH SPATIAL MODULATION OF MAGNETIZATION IN THE EVALUATIONOF CHRONIC CENTRAL PULMONARY THROMBOEMBOLI

PURPOSE: To assess the diagnostic value of magnetic resonance (MR) ima ging with SPAMM (spatial modulation of magnetization) in the identific ation of chronic central pulmonary thromboemboli. MATERIALS AND METHOD S: Twelve patients with pulmonary hypertension and five healthy volunt eers were prospectively studied with a 1.5-T MR imaging system. The SP AMM technique was integrated into a conventional cardiac-synchronized spin-echo (SE) sequence. Six of the ii patients had central thromboemb oli. RESULTS: In the healthy subjects, intravascular stripes in the ce ntral pulmonary arteries disappeared as a result of flow within 100 ms ec after the R wave. Areas of persistent stripes were identified in se ven of eight central pulmonary arteries with thromboemboli. Conversely , in the 16 central pulmonary arteries without clot, intraluminal stri pes disappeared despite the presence of flow-related signal (sensitivi ty = 88%, specificity = 100%, accuracy = 96%). CONCLUSION: SPAMM appea rs to be a simple and effective technique for differentiating central pulmonary arterial thromboemboli from flow-related signal frequently o bserved with pulmonary hypertension.