Magnetic Resonance Imaging Evaluation of Pulmonary Vascular Malformations: Materials
Since July 1987, 11 patients have been referred to our institution with the request to “rule out PVM.” This patient population included six male and five female patients ranging in age from 16 to 83 years. Four of these patients were symptomatic with hypoxemia, dyspnea on exertion, or had an audible bruit. The remaining seven patients had an unsuspected abnormality on chest radiograph or CT ordered by their referring physicians for various reasons other than “rule out PVM.” One of the symptomatic patients had Osler-Weber-Rendu syndrome.
All MRI studies were performed on a 1.5-T scanner (Signa, General Electric Medical Systems, Milwaukee). The spin-echo sequences were performed with respiratory compensation and cardiac gating using a single-phase, multislice acquisition such that the TR was determined by the patient’s heart rate (55 to 112 bpm). For the relatively Ti-weighted images performed in the coronal and axial planes, the TR was determined by one R-R interval, and the ТЕ was 15 or 20 ms; for T2-weighted images performed in the axial plane, a dual-echo cardiac gated technique was utilized yielding TR of 2,000 to 3,000 ms and ТЕ of 15 or 20 ms for the first echo and ТЕ of 70 or 80 ms for the second echo, respectively. The coronal and axial spin-echo acquisitions were 7 mm thick with a 3-mm intersection gap. Click Here
Prior to our obtaining cine GRE capabilities, a single-slice breath-held GRASS (gradient-recalled acquisition in the steady state) technique was used (one case) with a TR of 33 ms, a ТЕ of 13 ms, a flip angle of 30°, and first-order gradient moment nulling (flow compensation). The cine GRE sequences were performed in the coronal and/or the axial planes with an effective TR of 75 ms (three locations per acquisition), ТЕ of 7 to 13 ms, flip angle of 30 to 45°, cardiac synchronized incrementation of the phase encoding, respiratory compensation, first-order gradient moment nulling, 16 phases of the cardiac cycle, and section thickness of 5 to 10 mm with no intersection gap.