A new study on diffusion tensor imaging of the whole visual pathway fiber bundle and clinical application / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>With conventional imaging methods only the morphous of the visual nerve fiber bundles can be demonstrated, while the earlier period functional changes can not be demonstrated. We hypothesized that diffusion tensor imaging (DTI) would demonstrated the whole optic never fiber bundle and visual pathway and the earlier period functional changes. The purpose of the present study was to evaluate the application of DTI technique in the demonstration of the whole optic never fiber bundle and visual pathway, and the influence of orbital tumors on them.</p><p><b>METHODS</b>GE 1.5 T signa HD MR System, and the software package DTV2 were adopted. The total 45 subjects were enrolled, including 15 volunteers and 30 patients. All patients had ocular proptosis from minor to major. Seven patients had visual acuity decrescence.</p><p><b>RESULTS</b>The nerve fiber bundles, e.g. optic chiasma, optic tract and optic radiation in posterior visual pathway were well demonstrated in all cases. Wherein, the intact whole visual pathway fiber bundles were clearly revealed in 10 volunteers and 17 patients, and optic nerve was not wholly revealed in the rest of the subjects. Shift of optic nerve caused by compression and partial deformation were seen in 7 patients with orbital tumor. In 6 of 7 patients, DTI displayed significant abscise and deformation of visual nerve. Chi-square test indicated significant correlation between visual acuity decrescence and DTI visual nerve non-display.</p><p><b>CONCLUSIONS</b>Visual nerve fiber bundles and the whole visual pathway were visualized in most of patients with DTI. It might be an effective method of providing imaging evidence for visual nerve fiber earlier period functional changes, and laid a foundation for the study in other cranial nerves.</p>

Preliminary clinical application of contrast-enhanced MR angiography using three-dimensional timeresolved imaging of contrast kinetics / 中华放射学杂志

Objective To assess the clinical application of contrast-enhanced MR angiography using three-dimensional(3D)time-resolved imaging of contrast kinetics(CE-MRA 3D-TRICKS).Methods TRICKS is a high temporal resolution(2—6s)MR angiographic technique using a short TR(2.8— 4.0 ms)and TE(0.9—1.3 ms),partial echo sampling and the central part of the k-space being updated more frequently than the peripheral part of the k-space.Pre-contrast mask 3D images are first acquired and 15--20 sequential 3D images following bolus injection of Gd-DTPA are then acquired.Results Thirty patients underwent contrast-enhanced MR angiography using TRICKS.Twelve vertebral arteries were well displayed on TRICKS.Seven of them showed normal,bilateral vertebral artery stenosis was shown in 1 case, and unilateral vertebral artery stenosis was shown in 4 wth aecompaning ipsilateral carotid artery bifurcation stenosis in one case.Bilateral renal artery showed normal in 4 cases,and the artery in transplanted kidney showed normal in one case and stenosis in another case.The cerebral artery showed normal in 2 cases, sagittal sinus thrombosis was detected in one case and intracranial arteriovenous malformation in one case. Pulmonary artery displayed normal in 3 cases,pulmonary artery thrombosis was seen in one case and pulmonary sequestration's abnormal feeding artery and draining vein was revealed in one case.The feeding artery in left lower limb fibrolipoma was showed in one case.The radial-ulnar artery artificial fistula stenosis was seen in one case,and left antebrachium hemangioma was showed in one case.Conclusion TRICKS can clearly delineate the whole body vascular system and can reveal any vascular abnormality.It is convenient and with high successful rate,which make it the first method of choice in displaying vascular abnormality.