[MR coronary angiography with MS-325, a blood pool contrast agent: comparison of an inversion recovery steady-state free precession with an inversion recovery fast low angle shot sequence in volunteers]. / MR-Koronarangiographie mit MS-325, einem Blood-Pool-Kontrastmittel: Vergleich einer Inversion Recovery Steady-State Free Precession und einer Inversion Recovery Fast Low Angle Shot Sequenz in Probanden.

PURPOSE: To compare the signal-to-noise and contrast-to-noise ratio as well as the image quality of 3D inversion recovery steady-state free precession (IR-SSFP) and 3D inversion recovery fast low angle shot (IR-FLASH) sequences for contrast-enhanced breath-hold MRCA. MATERIALS AND METHODS: 24 healthy volunteers (10 female, 14 male, mean age 29.8 +/- 6.1 years) were involved in this study. All examinations were performed on a 1.5 T MR scanner (Magnetom Sonata, Siemens, Germany) after injection of 0.05 mmol/kg body weight MS-325 (EPIX Pharmaceuticals, Cambridge, MA and Schering AG, Berlin, Germany). MRCA was performed using IR-SSFP (TR 3.8 ms, TE 1.6 ms, FA 65 degrees , 35 phase encoded steps, bandwidth 540 Hz/pixel, slice thickness 1.5 mm, in-plane resolution 1.2 x 0.9 - 1.4 x 1.0 mm) and IR-FLASH (TR 3.8 ms, TE 1.6 ms, FA 25 degrees , bandwidth 490 Hz/pixel, slice thickness 1.5 mm, in-plane resolution 1.2 x 0.9 - 1.4 x 1.0 mm) sequences. For all scans the inversion time was set to null the signal intensity of the myocardium. Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) measurements (blood versus myocardium) were performed. The image quality was assessed based on a 5-point scale ranging from 1 (excellent) to 5 (non-diagnostic) by two radiologists in consensus. RESULTS: The mean signal-to-noise ratio of blood (27.7 +/- 4.7 vs. 22.6 +/- 4.9, P < 0.0001) and the contrast-to-noise ratio (21.0 +/- 4.3 vs. 15.8 +/- 4.3, P < 0.0001) showed significantly higher values for IR-SSFP sequences. The mean image quality scores were significantly higher for SSFP (3.6 +/- 0.7) than FLASH (2.8 +/- 0.9) sequences (P < 0.05). CONCLUSION: IR-SSFP sequences show a considerable overall improvement in image quality compared to IR-FLASH sequences for MRCA after injection of a gadolinium-based blood pool contrast agent.

[Detection and characterization of left ventricular thrombi by MRI compared to transthoracic echocardiography]. / Detektion und Charakterisierung linksventrikulärer Thromben mittels MRT im Vergleich zur transthorakalen Echokardiographie.

PURPOSE: Transthoracic echocardiography is the routine diagnostic procedure in assessing patients with left ventricular thrombi, but is limited by the acoustic window and poor contrast between thrombus and adjacent myocardium. This study evaluates the role of cardiac MRI in the detection of left ventricular thrombi in patients with chronic myocardial infarction compared to standard transthoracic echocardiography. MATERIALS AND METHODS: In 82 patients (55 men and 27 women, age 36 to 79 years, median 59 +/- 11 years) who suffered a myocardial infarction more than 6 months earlier, transthoracic echocardiography and MRI were performed. The MRI protocol included steady state cine imaging (true FISP: TR 3.0 ms, TE 1.5 ms, FA 65 degrees ) in standard long and short axis orientation and contrast-enhanced imaging using a 3D IR-FLASH sequence with long inversion time (TR 4 ms, TE 1.43 ms, FA 10 degrees , TI 300 ms) early, and a 2D IR-FLASH sequence with optimized inversion time (TR 8 ms, TE 4.3 ms, FA 20 degrees , TI 180 - 280 ms) late after administration of gadolinium. RESULTS: Transthoracic echocardiography depicted 12 thrombi. Contrast-enhanced MRI confirmed these 12 thrombi and detected 23 additional thrombi. With the exception of 2 very small apical thrombi only visible on contrast-enhanced MR images, spherical thrombi were diagnosed by both techniques, whereas only contrast-enhanced MRI was able to visualize mural thrombi. Left ventricular thrombi were more frequently diagnosed in patients with moderate to severe impairment of the left ventricular systolic function, 32/42 (76 %), or in patients with left ventricular aneurysms, 21/24 (84 %). CONCLUSION: Contrast-enhanced MRI is mostly superior to transthoracic echocardiography in diagnosing mural left ventricular thrombi in patients who had suffered a myocardial infarction. Intracavitary thrombi are more frequently found in patients with impaired regional and global left ventricular function.

Optimization of contrast-enhanced peripheral MR angiography with mid-femoral venous compression (VENCO).

PURPOSE: To compare a standard protocol for contrast-enhanced three-dimensional magnetic resonance angiography (3D CE-MRA) of the lower extremities to a high spatial resolution protocol with venous compression (VENCO) at the mid-femoral level. MATERIAL AND METHODS: 12 patients with peripheral arterial occlusive disease (8-males; age range, 52 - 74 years; mean 67.1 years; 4 females; age range, 57 - 71 years; mean 62.1 years) were examined once with a standard MR angiography (MRA) protocol, and a second time with a high spatial resolution protocol in combination with mid-femoral venous compression (60 mm Hg) for the last two stations. All imaging was performed on a 1.5 T whole-body MR scanner (Magnetom Sonata, Siemens Medical Solutions, Erlangen, Germany) using a dedicated coil and paramagnetic contrast agent (gadodiamide, Omniscan, Amersham, Oslo, Norway). Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated and image quality as well as venous overlay were assessed on a five-point scale for both examinations. Statistical significance was established at p < 0.05. RESULTS: Mean SNR and CNR values of the two lower stations with VENCO were statistically significantly higher in comparison to the standard protocol (66 +/- 8 vs. 52 +/- 11 and 53 +/- 9 vs. 41 +/- 8, respectively; p < 0.01). The same was true for overall image quality with VENCO (4.0 +/- 0.2 vs. 3.4 +/- 0.8; p < 0.05) and presence of venous overlay (3.5 +/- 0.4 vs. 4.1 +/- 0.9; p < 0.05), respectively. CONCLUSION: VENCO 3D CE-MRA is simple to put into practice and advances the performance of multi-station MRA strategies for assessment of the peripheral arterial vasculature.