ABSTRACT
Objective To investigate the spontaneous neural activity in the brain of patients with Alzheimer' s disease (AD) used 3 indicators of resting state-functional magnetic resonance (rs-fMRI) amplitude of low frequency fluctuation (ALFF), fractional amplitude of low frequency fluctuation (fALFF) and percentage amplitude fluctuation (PerAF). Methods Totally 36 clinically diagnosed AD patients and 40 healthy volunteers were scanned by fMRI in resting state respectively. ALFF, fALFF and PerAF were used to calculate and compare the changes of brain regions between the two groups. Results Compared with the normal control group, mALFF value in AD group increased significantly in bilateral caudate nucleus, medial frontal gyrus, superior frontal gyrus, gyrus rectus, anterior cingulate gyrus, olfactive cortex, left middle frontal gyrus and inferior frontal gyrus (P<0. 05). mALFF values decreased significantly in the right middle temporal gyrus, inferior temporal gyrus, inferior occipital gyrus, middle occipital gyrus, bilateral calcarine, cuneus, lingual gyrus, superior occipital gyrus, vermis, precuneus and other regions (P<0. 05). In AD group, mfALFF value of right inferior temporal gyrus, anterior cerebellar lobe, fusiform gyrus, left superior frontal gyrus, medial frontal gyrus, middle frontal gyrus, inferior frontal gyrus, gyrus rectus and anterior cingulate gyrus increased significantly (P<0. 05); mfALFF values decreased significantly in bilateral lingual gyrus, left calcarine, cuneus, superior occipital gyrus, middle occipital gyrus and vermis (P<0. 05). In AD group, mPerAF value increased significantly in bilateral gyrus rectus, anterior cingulate gyrus, medial frontal gyrus, left superior frontal gyrus, caudate nucleus, middle frontal gyrus, inferior frontal gyrus, olfactive cortex and insula (P<0. 05); mPerAF values decreased significantly in bilateral calcarine, cuneus, superior occipital gyrus, lingual gyrus, precuneus, left fusiform gyrus, inferior occipital gyrus, right superior parietal lobule, angular gyrus, middle temporal gyrus, inferior temporal gyrus and middle occipital gyrus (P < 0. 05). Conclusion The default mode network (DMN) and visual network of AD patients are characterized by abnormal brain activity, with the most significant neural activity in the prefrontal cortex and visual cortex.
ABSTRACT
Objective To investigate whether physiological asymmetry of normal bilateral superficial veins located in dorsolateral aspects of hemispheres is existed on susceptibility-weighted imaging (SWI). Methods There were 45 healthy young volunteers in this study. After exclusion of intracranial lesions by using common brain magnetic resonance imaging examination, they underwent SWI examination. We observed the number, diameter and signal intensity of superficial veins located in dorsolateral aspects of hemispheres according to the images of SWI on transverse sections through the centrum semiovale, trunk of corpus callosum, splenium of corpus callosum, and superior colliculus. Results The frequencies of asymmetry of the bilateral superficial veins located in dorsolateral aspects of hemispheres on transverse sections through the centrum semiovale, trunk of corpus callosum, splenium of corpus callosum, and superior colliculus were 20.0%, 37.8%, 35.6% and 26.7%, respectively. The frequencies of mild asymmetry of the bilateral superficial veins located in dorsolateral aspects of hemispheres on above transverse sections were 17.8%, 31.1%, 31.1% and 24.4% respectively, and the frequencies of prominent asymmetry were 2.2%, 6.7%, 4.4% and 2.2%, respectively. According to chi square test, there was no gender difference in asymmetry of the bilateral superficial veins located in dorsolateral aspects of hemispheres. Conclusion SWI technique was used to show the physiological asymmetry of the bilateral superficial veins located in dorsolateral aspects of hemispheres on different transverse sections. Most of them are mild. Therefore, when cerebrovascular disease occurs, if transverse sections of images by SWI show asymmetry of the bilateral superficial veins located in dorsolateral aspects of hemispheres, the possibility of physiological phenomenon is needed to take into consideration.
ABSTRACT
Objective To image the veins around the foramen of monro (FM), to build the 3D model of them, to construct venous network in this area and to explore the spatial positional correlation between FM and veins around it. Methods Totally 60 healthy subjects were selected to get the original images on 3. 0 T MR and procesed the original images by minimum intensity projections (mIP) and Materialise’ s interactive medical image control system (Mimics), built the 3D model of the veins around FM, observed and analyzed the morphology of FM and the veins around it on original and processed images. Results The displaying rate of FM was 65% (78 sides), the displaying rate of internal cerebellar veins (ICV) was 100% (120 sides), the diameter was (2. 13±0. 30) mm. The displaying rate of anterior septal vein (ASV) was 100% (120 sides), the diameter was(0. 69±0. 19)mm. The displaying rate of superior thalamostriate vein (STV) was 98. 3% (118 sides), the diameter was (1. 47± 0. 38) mm. The displaying rate of superior choroidal vein (SCV) was 82. 5% (99 sides), the diameter was(0. 40±0. 18)mm. According to the relationship between the converging point of the tributaries of ICV and the location of FM, FMs were classified into 5 types:ⅠA, 24. 2% (29 sides), ASV converged into ICV at the venous angle and closed to the posterior edge of FM; ⅠB, 13. 3% (16 sides), ASV converged into ICV away from the venous angle and the posterior edge of FM; ⅡA, 45% (54 sides), ASV converged into ICV at the false venous angle and closed to the posterior edge of FM; ⅡB, 15. 8% (19 sides), ASV converged into ICV away form the false venous angle and the posterior edge of FM. Ⅲ, 1. 7% (2 sides), STV was absent. Conclusion FM and the veins around it are visible on the susceptibility weighted imaging(SWI). It can be constructed by Mimics that the 3D model of ICV, its tributaries, FM and the converging points of the major veins. The classification of FMs is meaningful to the option of surgical approaches through FM.
ABSTRACT
Objective Make use of image dentate nucleus and the veins around it on susceptibility weighted images (SWI), explore the correlation between the location of hilum of dentate nucleus and the venous variation of dentate nucleus. Methods Selecting 51 healthy adults (24 men, 27 women) at the age between 18 and 30 years old to get the original images on 3. 0T MR. Process the original images by minimum intensity projections (mIP) observed and analyzed the morphology of dentate nucleus and veins around it on original and processed images. Results The length of dentate nucleus was (16. 64±0. 20)mm, and the width was (8. 36±0. 14)mm. There was no significant difference between bilateral dentate nucleus. The median angle of the long axis of the dentate nucleus was 26. 80° (interquartile distance was 34. 58°). The venous network of dentate nucleus was formed in 2 groups of veins: the lateral group, drained by the vein of the horizontal fissure and nuclear vein; the medial group, drained by vermian vein and central vein of dentate nucleus. These two groups had been further typing as follows: the lateral anterior group drained by the nuclear vein, finally opening to superior petrosal sinus; the lateral median group had plenty of small veins of lateral dentate nucleus converge into the vein of the horizontal fissure; the lateral posterior group drained by a lot of very small veins converging to vermian veins or medullary veins; the medial anterior group that the central vein of dentate nucleus and the paravermian vein were jointed at hilum of dentate nucleus, opening into straight sinus; the medial posterior group usually converged into tributaries of vermian vein, or converged with paravermian vein into tributaries of vermian vein. Totally 75. 49% of hilums of dentate nucleus were located at upper inner quadrant, the other 24. 51% of them were located at lower inner quadrant. Conclusion Dentate nucleus and its veins are clearly visible on the susceptibility weighted images, and the location of the hilum of dentate nucleus may be related to the abouchement of paravermian vein.