Magnetic Resonance Imaging of Brain Involvement in Dogs Using Paramagnetic Contrast Enhancement with Mn(II)-DCTA P.

Experimental study of a new paramagnetic complex Mn-DCTA is carried out. The complex (0.5 M manganese(II) solution with trans-1,2-diamine cyclohexane-N,N,N',N'-tetraacetic acid; Cyclomang) was used for contrast magnetic resonance imaging visualization of CNS involvement in dogs with severe forms of Babesia canis infection. CNS injuries were visualized in all cases, with highly intense contrasting at the expense of Mn-DCTA accumulation at the periphery of the damaged zone. Quantitative evaluation of the paramagnetic accumulation in the focus showed that the amplification index wa s 1.19±0.11 for the central areas and 1.47±0.17 for the peripheral ones. The pituitary (1.18±0.05) and vascular plexuses of the lateral ventricles (1.12±0.09) were also contrasted. Injection of the paramagnetic to dogs was not associated with any kinds of pathological or physiological reactions. Mn-DCTA complex allowed contrast visualization of the focal injuries to the CNS and could be regarded as a paramagnetic contrast agent for magnetic resonance imaging of brain injuries in dogs.

[Simultaneous magnetic resonance angiographic and tomographic assessment of atherosclerotic plaques of carotid arteries with paramagnetic contrasting by cyclomang].

The authors studied a possibility of simultaneously performing magnetic resonance (MR) angiography of carotid arteries and contrast-enhanced MR tomography of atherosclerotic plaques of carotid arteries. We examined a total of 16 patients presenting with disseminated atherosclerosis and 8 patients of the control group. Quadrature coils for examination of the head were used in order to sequentially perform MR tomography of the brain, MR angiography of carotid arteries and MR tomography of atherosclerotic plaques of carotid arteries with contrasting by 0.5M cyclomang. Angiography was carried out by means of the technique of 3D GR FFE of rapid gradient echo (TR/TE/FA/ST=10 ms/2.7 ms/20°/1.5 mm). MR tomography of the carotid arteries bifurcation was performed in the T1-weighted spin-echo mode: TR=500-900 ms, TE=10 ms, slice sickness 1-3 mm into the matrix 256x256 voxels, with the voxel size measuring 0.2x0.2x2 mm. The average time of passing of the paramagnetic through the blood vessels of the cerebral hemispheres in the control group amounted to 4.23±0.14 s for the left hemisphere and to 4.27±0.15 s for the right one. The mean time of bolus passing in patients with predominantly unilateral stenosis of the internal carotid artery amounted to 4.89±0.23 on the affected side, equalling 4.56±0.19 s on the unaffected side (p>0.05). In bilateral lesions these indices for the left and right hemispheres amounted to 4.98±0.21 s and 5.01±0.16 s (p>0.05), respectively. Contrast-enhanced MR angiography with cyclomang made it possible in all cases to visualize the localization and character of stenosis. The index of stenosis degree calculated for MR-angiogram highly significantly correlated with the indices of the ultrasonographic examination performed according to the ECST technique both for cases of unilateral (r=0.87, p<0.05) and cases of bilateral stenotic lesion (r=0.85, p<0.05). Inhomogeneous soft plaques with high content of lipids had high values of the enhancement index on contrasting--1.26±0.07, whereas hard fibrous avascular plaques--1.09±0.04 (p<0.05). The total time of the examination amounted to 41±5 min while performing time-fly MR-angiography and to 29±5 min without it. A conclusion was made that simultaneous MR angiography and contrast-enhanced (with Mn-paramagnetic) MR tomography of carotid arteries is possible and appropriate within the framework of a single study using quadratic coil for the head.