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The authors compared two-dimensional (2D) and three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography in ten healthy volunteers to establish which of two techniques is more effective in representing the pulmonary segmental arteries. No respiratory trigger or electrocardiogram gating was used. Presaturation pulses were used to eliminate venous flow. Images acquired in the sagittal planes were processed using maximum intensity projection. A total of 200 segmental arteries were evaluated with each technique by three observers (M.S., C.S., A.R.) in terms of vessel visibility. There was no significant difference among the observers' interpretations (p > 0.05). On average, 2D fast, low-angle shot breath-hold TOF sequences showed 136.1 of 200 (68%) segmental arteries, 74.1 of 100 in the right lung and 62 of 100 in the left lung. Three-dimensional fast imaging with steady state precession showed 171.6 of 200 (85.8%) segmental arteries, 94 of 100 in the left lung and 77.6 of 100 in the left lung. Three-dimensional imaging appeared to be better than 2D MRA for demonstration of segmental pulmonary arteries.

The aim of this work was to optimize the magnetic resonance angiography (MRA) technique for the selective study of the pulmonary veins. Twenty consecutive patients (13 men and 7 women; mean age: 30.5 years) were examined. MRA was performed with a 1 T superconductive magnet and the 3D time of flight (TOF) technique. Fast sequences (3D FISP: TR 58 ms, TE 6 ms, FA 20 degrees, matrix 192 x 256; and 2D FLASH: TR 44 ms, TE 10 ms, FA 30 degrees, matrix 192 x 256) were used. Coronal and sagittal images were submitted to MIP processing; presaturation pulses for the pulmonary arteries were located in the mediastinal region. In the right lung, 3D TOF on the coronal plane well showed 124 veins, while sagittal images showed 106 veins. In the left lung, 3D TOF on the coronal plane well showed 96 vessels, while sagittal images showed 44 vessels. In the right lung, 2D TOF on the coronal plane well showed 54 veins, while sagittal images showed 36 vessels. In the left lung, 2D TOF on the coronal plane well showed 22 vessels, while sagittal images showed 21 vessels. Therefore, 3D TOF yielded better results than 2D TOF (p < 0.05). To conclude, 3D TOF with contrast agent administration is a useful tool to study the pulmonary veins; those with a larger caliber are better depicted and the integration of coronal and sagittal images depicts more veins.

This work was aimed at studying the origin of the epiaortic vessels with Magnetic Resonance Angiography (MRA). Twenty normal volunteers (mean age: 21.5 years) were examined with MRA with a superconductive magnet at 1 T (Impact). All volunteers were examined with a body coil and the time of flight (TOF) technique. The FISP 3D TONE sequence was used, with the following parameters: TR 46 ms, TE 10 ms, FA 20 degrees, ST 2.2 mm, matrix 192 x 256. The images, acquired on the axial plane with three presaturation pulses, were rotated according to the maximum intensity projection on the Z axis. To classify the images, a multiple choice card was used by a reader, with three diagnostic judgements for the different segments of the vessels (i.e., good, poor and not visualized). 3D TOF MRA permitted good visualization of the right and left common carotid in 80% and 77% of cases, of the right and left vertebral arteries in 55% and 50% of cases, of the left and right subclavian arteries in 47% and 62% of cases, and of the anonymous artery in 100% of cases. To conclude, our preliminary results indicate FISP 3D TOF MRA as the best noninvasive technique to study the origin of the epiaortic vessels.

The authors optimized the Magnetic Resonance Angiography (MRA) technique for the study of the different portions of the pulmonary artery-i.e., the common trunk, right and left main arteries and the lobar, segmental and subsegmental branches. Twenty volunteers were examined with MRA of the pulmonary arteries with a 1-T superconductive magnet (Impact) and the time-of-flight (TOF) technique. The volunteers were divided into two groups by age (ranges: 20-40 and 41-70 years). The trunk and main branches were studied with the 2D TOF technique, while 2D TOF images were compared with 3D TOF images in the study of peripheral (lobar, segmental and subsegmental) branches. The images were processed with the maximum intensity projection (MIP). In the statistical comparison between 2D and 3D TOF images, the t-test was used (p < 0.05). The 2D TOF images acquired on the sagittal oblique and coronal planes, with presaturation pulses, permitted optimal depiction of the trunk and of the right and left branches in all the volunteers. Both 2D and 3D TOF images yielded excellent images in the study of the lobar branches. In the volunteers under 40 years of age, 3D TOF sequences visualized the peripheral (segmental and subsegmental) vessels better than 2D TOF sequences (451 vs. 361); the difference was statistically significant. In the volunteers over 41 years of age, the ratio was reversed: 467 for 2D TOF vs. 362 for 3D TOF sequences; again, the difference was statistically significant. The correct integration of 2D and 3D TOF sequences, according to the different segments of the pulmonary artery and to patients' age, permitted the complete and accurate visualization of the pulmonary arteries with MRA.