DIFFERENTIAL DIAGNOSIS IN THE INTRACRANIAL DISEASES: PROTON MAGNETIC RESONANCE S PECTROSCOPY STUDY

Objective To investigate th e value of proton magnetic resonance spectroscopy ( 1H-MRS) on diagnosis a nd differential diagnosis of the intracranial diseases by the MRS results of 52 patients. Methods 12 patients with benign glioma, 16 patients with malignant glioma, 10 patients with meningioma, 8 patients with virus encephalitis, and 6 patients with cerebral infarction underwent MRS in th e lesion region. We measured the area within the spectra of N-acetyl-aspartate (NAA), creatine/phosphocreatine (Cr), choline compounds (Cho), and lactate (Lac ). Results The spectra of meningiomas were characterized by abs ence of NAA. The spectra of gliomas were characterized by the decrease of NAA an d Cr, but the increase of Cho. The ratio of Cho to Cr was 2.25±1.21 in benign g liomas, while the ratio of Cho to Cr was 4.65±2.21 in malignant gliomas. The sp ectra of virus encephalitis appeared the decrease of NAA and the normality of Cr , with the 1.25±0.21 ratio of Cho/Cr. The apparent Lac wave could be seen in al l cerebral infarctions. Conclusion The value of 1H-MRS plays a significant role in the diagnosis and differential diagnosis of gliomas, mening iomas, virus encephalitis, and cerebral infarctions.

Altered relationship between thickness and intrinsic activity amplitude in generalized tonic–clonic seizures

A thinner cortex has higher potential for binding GABA receptor A which is associated with larger amplitudes of intrinsic brain activity(i BA). However, the relationship between cortical thickness and i BA is unknown in intact and epileptic brains. To this end, we investigated the relationship between cortical thickness measured by highresolution MRI and surface-based i BA derived from resting-state functional MRI in normal controls(n = 82) andpatients with generalized tonic–clonic seizures(GTCS)only(n = 82). We demonstrated that the spatial distribution of cortical thickness negatively correlated with surface-based i BA amplitude at both whole-brain and within independent brain functional networks. In GTCS patients,spatial coupling between thickness and i BA amplitude decreased in the default mode, dorsal attention, and somatomotor networks. In addition, the vertex-wise acrosssubject thickness–i BA amplitude correspondence altered in the frontal and temporal lobes as well as in the precuneus in GTCS patients. The relationship between these two modalities can serve as a brain-based marker for detecting epileptogenic changes.

Effect of image registration on longitudinal analysis of retinal nerve fiber layer thickness of non-human primates using Optical Coherence Tomography(OCT)

Background:In this paper we determined the benefits of image registration on estimating longitudinal retinal nerve fiber layer thickness(RNFLT)changes.Methods:RNFLT maps around the optic nerve head(ONH)of healthy primate eyes were measured using Optical Coherence Tomography(OCT)weekly for 30 weeks.One automatic algorithm based on mutual information(MI)and the other semi-automatic algorithm based on log-polar transform cross-correlation using manually segmented blood vessels(LPCC_MSBV),were used to register retinal maps longitudinally.We compared the precision and recall between manually segmented image pairs for the two algorithms using a linear mixed effects model.Results:We found that the precision calculated between manually segmented image pairs following registration by LPCC_MSBV algorithm is significantly better than the one following registration by MI algorithm(p<<0.0001).Trend of the all-rings and temporal,superior,nasal and inferior(TSNI)quadrants average of RNFLT over time in healthy primate eyes are not affected by registration.RNFLT of clock hours 1,2,and 10 showed significant change over 30 weeks(p=0.0058,0.0054,and 0.0298 for clock hours 1,2 and 10 respectively)without registration,but stayed constant over time with registration.Conclusions:The LPCC_MSBV provides better registration of RNFLT maps recorded on different dates than the automatic MI algorithm.Registration of RNFLT maps can improve clinical analysis of glaucoma progression.