Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.59 (MIP)
 4,906 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MR angiography (MRA) proved to be promising combined to MR imaging (MRI) in the assessment of intrathoracic masses. Sequential FLASH 2D angiograms were acquired in breath-hold technique using the following parameters: TR = 30 ms, TE = 10 ms, FA = 30 degrees. Section thickness was 5 mm with 1 mm overlap between sequential sections. Individual conditions of the examination were achieved by an automatized control procedure. Targeted MIP postprocessing resulted in 3D reconstructions illustrating vascular anatomy and avoiding superimposition. Presentation should be done by cine-mode for better spatial impression. This method was evaluated in a prospective study of 21 patients with malignant pulmonary and mediastinal masses in addition to spin-echo imaging. The diagnostic contribution concerning the relationship between the mass and the vasculature like displacement, stenosis, and poststenotic perfusion defect were assessed.
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PMID:[MR angiography. Its use in pulmonary and mediastinal space-occupying lesions]. 163 98

This study was carried out to evaluate time-of-flight RA in renal artery stenosis (RAS) in selected hypertensive patients (n = 41). In i.a. DSA studies, 10 unilateral, 8 bilateral RAS, and 4 unilateral RA occlusions were proven. MRA was done in coronal and axial 2D technique (FLASH), and in 3D technique (FISP) using GE-pulse sequences. DSA results were correlated with both 2D-individual slices, 2D- and 3D-MIP angiograms. Highest sensitivity and specificity was found for the axial 2D individual slice analysis (88%, 85% resp.), followed by the 3D-MIP MRA (78%, 80% resp.), and axial 2D-MIP MRA (73%, 79% resp.). MRA of renal arteries used in this study shows to be not adequate to DSA results due to many drawbacks. All MRA techniques, in particular the 3D-technique, tend to overestimate RAS occasionally pretending occlusions.
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PMID:[The evaluation of 2D- and 3D-"time of flight" magnetic resonance angiography (MRA) in the diagnosis of renal artery stenoses]. 163 7

MR angiography of the lumbar venous plexuses (MR venography, MRV) was performed with thirty-one cases using a 1.5 T superconducting MR unit. Two MRV techniques, FISP based subtraction method and FLASH based TOF method were used for this study. After obtaining coronal or axial data acquisition, angiographic images were reconstructed by MIP method. Gd-DTPA was injected in all cases. The over all detectability of the lumbar venous plexuses was more than 77% on coronal data acquisition with subtraction method that better delineated slow-in-plane flow with optimal tissue signal suppression around the vessels. The coronal images were superior to axial ones in terms of wider demonstration of vertebral venous plexuses. Whole lumbar spine can be demonstrated in coronal plane. The use of Gd-DTPA to reduce the saturation effect of venous flow was necessary for better visualization of the lumbar venous plexuses.
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PMID:[2D MR angiography of lumbar venous plexuses]. 812 69

In abdominal aortic aneurysm ultrasonography, contrast-enhanced CT, and digital subtraction angiography (DSA) are the preoperative diagnostic methods of choice accepted today. It was the goal of this study to evaluate time-of-flight magnetic resonance angiography (MRA) in comparison with other radiographic procedures in different types of aneurysms. In 24 patients with proven aortic aneurysm, projection angiograms (MIP algorithm) of the abdominal aorta and pelvic arteries were performed using two-dimensional gradient echo multi slice sequence (FLASH, TE/TR = 10/51 ms; three slices; breathhold technique; flip angle = 30 degrees) in coronal orientation. In addition, renal arteries were imaged in axial slices. The information provided by MRA was comparable to that of DSA (perfused vascular lumen) and contrast-enhanced CT (alteration of vascular wall). Thus dilatation, thrombus, dissection, or inflammation could be analysed safely. Extension of the aneurysm to pelvic arteries could be evaluated in most cases by rotation of the projection angiograms; ostial renal artery disease could be visualized on axial slices. If further technical improvement of MRA is presupposed, this noninvasive method may completely replace the invasive procedures of contrast-enhanced CT and DSA in the future.
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PMID:[2D-time-of-flight MR angiography in the diagnosis of abdominal aorta aneurysms]. 836 6

Twenty volunteers were examined by means of 2D and 3D time of flight (TOF) Magnetic Resonance angiography (MRA) of the renal arteries. The possible diagnostic applications of MRA were also evaluated in 6 patients with renovascular diseases. MRA examinations of the renal arteries were performed with a 1.5 T superconductive magnet (Magnetom Siemens) and circular body coil. Ten volunteers were studied with 3D FISP sequences (FA 25 degrees, TR 40 ms, TE 7 ms, ST 1 mm, Ma 256 x 256, FOV 500); the images were acquired on the axial plane and were rotated, in MIP and target MIP, on the axial (z) and sagittal (x) axes. The other 10 volunteers were studied with 2D FLASH sequences (FA 18 degrees, TR 300 ms, TE 8 ms, ST 4 mm, overlap 1 mm, Ma 256 x 256, FOV 500); the images were acquired on the axial and coronal planes and were rotated, in MIP and target MIP, on the axial (z) and sagittal (x) axes. The ostium and proximal segments (1-15 mm) were always easily identified with 2D and 3D sequences, the distal segments (16-35 mm) were also clearly demonstrated in 11 cases with 3D (55%) and in 16 cases with 2D (85%) sequences. The bifurcations and branch vessels of the renal arteries were easily depicted with 3D TOF sequences in 7 cases only. Combined 3D and 2D TOF images permitted the thorough evaluation of the renal arteries. In renovascular diseases, 2D and 3D TOF images clearly demonstrated occlusions and stenoses of the proximal segment (1-15 mm). 2D TOF sequences only permitted the visualization of a case of fibromuscular dysplasia in the distal segment. Our results suggest that 2D and 3D TOF MRA exhibits good potentials as a noninvasive screening technique for the evaluation of renovascular diseases.
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PMID:[Angiography with magnetic resonance++ of the renal arteries: bidimensional versus tridimensional "time of flight" technique]. 849 63

The authors investigated the diagnostic capabilities of gradient echo sequences (magnetic resonance angiography) in the study of induratio penis plastica. Twenty patients (mean age: 39 years) were examined. MRA was performed with a superconductive magnet (1.5 T) and a Helmoutz coil; the dynamic test with PGE (20-40 mg) was also carried out. The images acquired on the axial and sagittal planes were processed according to the MIP. The FLASH 2D sequence was used with the following parameters: FA 18 degrees, TR 40 ms, TE ms, MA 256 x 256, slice thickness 5 mm. A multiple choice card was filled in by a reader with the following diagnostic information: identification and localization of the plaques and involvement by the plaques of the albuginea, corpora cavernosa, septum and dorsal vein; surgery was the gold standard. MRA showed 10/11 plaques ranging 8-30 mm in diameter and missed a 5-mm plaque. Moreover, MRA depicted the infiltration of the albuginea in 10/10 cases, of the septum in 3/3 cases, of the dorsal vein in 4/4 cases and of the corpora cavernosa in 9/9 cases. Our preliminary experience shows that in the study of induratio penis plastica, the gradient echo sequence (MRA) permits better depiction of the plaques and of the infiltration of the corpora cavernosa, septum and albuginea.
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PMID:[Induratio penis plastica: the diagnostic possibilities of gradient-echo sequences (magnetic resonance angiography)]. 864 54

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.
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PMID:[Magnetic resonance angiography in the study of pulmonary veins: TOF 3D versus 2D]. 924 15