In Vivo Assessment of Neurodegeneration in Type C Niemann-Pick Disease by IDEAL-IQ.

Objective: To noninvasively assess the neurodegenerative changes in the brain of patients with Niemann-Pick type C (NPC) disease by measuring the lesion tissue with the iterative decomposition of water and fat with echo asymmetry and least square estimation-iron quantification (IDEAL-IQ). Materials and Methods: Routine brain MRI, IDEAL-IQ and 1H-proton magnetic resonance spectroscopy (1H-MRS, served as control) were performed on 12 patients with type C Niemann-Pick disease (4 males and 8 females; age range, 15-61 years; mean age, 36 years) and 20 healthy subjects (10 males and 10 females; age range, 20-65 years; mean age, 38 years). The regions with lesion and the normal appearing regions (NARs) of patients were measured and analyzed based on the fat/water signal intensity on IDEAL-IQ and the lipid peak on 1H-MRS. Results: Niemann-Pick type C patients showed a higher fat/water signal intensity ratio with IDEAL-IQ on T2 hyperintensity lesions and NARs (3.7-4.9%, p < 0.05 and 1.8-3.0%, p < 0.05, respectively), as compared to healthy controls (HCs) (1.2-2.3%). After treatment, the fat/water signal intensity ratio decreased (2.2-3.4%), but remained higher than in the HCs (p < 0.05). The results of the 1H-MRS measurements showed increased lipid peaks in the same lesion regions, and the micro-lipid storage disorder of NARs in NPC patients was detectable by IDEAL-IQ instead of 1H-MRS. Conclusion: The findings of this study suggested that IDEAL-IQ may be useful as a noninvasive and objective method in the evaluation of patients with NPC; additionally, IDEAL-IQ can be used to quantitatively measure the brain parenchymal adipose content and monitor patient follow-up after treatment of NPC.

Brain MRI findings in acute hepatic encephalopathy in liver transplant recipients.

Acute hepatic encephalopathy has significant morbidity and mortality in liver transplant recipients unless it is promptly treated. We evaluated the brain magnetic resonance (MR) imaging findings associated with acute hepatic encephalopathy in transplant recipients. We retrospectively reviewed the clinical and imaging data and outcomes of twenty-five liver transplant patients (16 male; mean age, 49.3 years) with clinically diagnosed acute hepatic encephalopathy and forty liver transplant patients (20 males; mean age, 45.5 years) without neurological symptoms suggestive of hepatic encephalopathy at our institution. Bilateral symmetric hyperintensities of the insular cortex and cingulate gyrus were observed in twenty-one patients (84.00%), bilateral symmetric extensive increased cortical signal intensity (involving two or more regions) was observed in 72.00% of the patients, leptomeningeal enhancement in 73.68%, and visualization of prominent venules in 52.00%. The most common symptom at diagnosis was rigidity (n = 14), and the plasma ammonia levels ranged from 68.63 to 192.16 µmol/L. After active treatment, 17 patients gradually recovered, four patients suffered from mild or moderate neurologic deficits, and four patients with widespread brain edema died. The specific brain MR imaging features were bilateral symmetric increased cortical signal intensity, especially in the insular cortex and cingulate gyrus, leptomeningeal enhancement, visualization of the prominent venules, and widespread brain edema. These features may indicate poor prognosis and should alert radiologists to the possibility of acute hepatic encephalopathy in liver transplant recipients and encourage clinicians to prepare appropriate treatment in advance.

Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study.

Aphasia is an acquired language disorder that is a common consequence of stroke. The pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language. The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults. The activation frequency, volumes, and intensity in the regions related to language, such as the left inferior frontal gyrus (Broca's area), the left superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca's area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the left inferior temporal gyrus was stronger in patients compared with healthy controls. These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas.

[Magnetic resonance imaging findings of lesions in limbic system related structures in general paresis of insane].

OBJECTIVE: To analyze the magnetic resonance imaging (MRI) findings of lesions in the limbic system related structures in general paresis of insane (GPI) patients so as to explore its pathogenesis and provide a new MRI diagnostic method. METHODS: The clinical data and MRI findings of lesions in the limbic system related structures were retrospectively analyzed for a total of 31 GPI patients. The parameters were volume and signal abnormality. RESULTS: On MRI, structural abnormalities were found in amygdaloid body (n = 29), hippocampus (n = 28), insular lobe (n = 24), parahippocampal gyrus (n = 23), lenticular nucleus (n = 23), corpus callosum (n = 20), caudate nucleus (n = 11), hypothalamus (n = 10), anterior nucleus of thalamus (n = 10), cingulate gyrus (n = 8) and thalamus (n = 2). The frequent manifestations were atrophy, swelling, T2 hyperintensity in various structures and T2 hypointensity in lenticular nucleus. CONCLUSION: A frequent involvement of limbic system structures in GPI patients may be related with dementia and other psychiatric symptoms. Swelling and T2 hyperintensity of involved structures may be the characteristic MRI manifestations of GPI.

Diffusion tensor imaging of the brain in patients with Alzheimer's disease and cerebrovascular lesions.

BACKGROUND: Recent autopsy study showed a high incidence of cerebrovascular lesions in Alzheimer's disease (AD). To assess the impact of cerebrovascular pathology in AD, we used diffusion tensor imaging (DTI) to study AD patients with and without cerebrovascular lesions. MATERIALS AND METHODS: Conventional and DTI scans were obtained from 10 patients with probable AD, 10 AD/V patients (probable AD with cerebrovascular lesions) and ten normal controls. Mean diffusivity (D) and fractional anisotropy (FA) values of some structures involved with AD pathology were measured. RESULTS: D value was higher in AD patients than in controls in hippocampus and the cingulate gyrus. In AD/V patients, increased D value was found in the same structures and also in the thalamus and basal ganglia compared to controls. There was a significant difference of D value between AD and AD/V patients. FA value reduced in the white matter of left inferior temporal gyrus and in the bilateral middle cingulate gyrus in patients with AD/V compared with controls. The MMSE (mini-mental state examination) score significantly correlated with FA value in the right hippocampus (r=0.639, P<0.019), in the right anterior cingulate gyrus (r=0.587, P<0.035) and in left parahippocampal gyrus (r=0.559, P<0.047). CONCLUSION: Cerebrovascular pathology had stronger impact on the D value than the AD pathology alone did. Elevated D value in thalamic and basal ganglia may contribute to cognitive decline in AD/V patients. Reduced FA values in AD/V patients may indicate that cerebrovascular pathology induced more severe white matter damage than the AD pathology alone did.

White matter damage of patients with Alzheimer's disease correlated with the decreased cognitive function.

Increasing evidence demonstrates that there is marked damage and dysfunction in the white matter in Alzheimer's disease (AD). The present study investigates the nature of white matter damage of patients with Alzheimer's disease with diffusion tensor magnetic resonance imaging (DTI) and analyses the relationship between the white matter damage and the cognition function. DTI, as well as T1 fluid attenuated inversion recovery (FLAIR) and T2-FLAIR, was performed on probable patients of Alzheimer's disease, and sex and age matched healthy volunteers to measure the fractional anisotropy (FA) and mean diffusivity (MD) in the genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, and the white matter of frontal, temporal, parietal, and occipital lobes. FA was lower in the splenium of corpus callosum, as well as in the white matter of the frontal, temporal, and parietal lobes from patients with Alzheimer's disease than in the corresponding region from healthy controls and was strongly positive correlated with MMSE scores, whereas FA appeared no different in the anterior and posterior limbs of internal capsule, occipital lobes white matter, and the genu of corpus callosum between the patients and healthy controls. MD was significantly higher in the splenium of corpus callosum and parietal lobes white matter from patients than in that those from healthy controls and was strongly negative correlated with MMSE scores, whereas MD in the anterior and posterior limbs of internal capsule, as well as in frontal, temporal, occipital lobes white matter and the genu of corpus callosum, was not different between the patients and healthy controls. The most prominent alteration of FA and MD was in the splenium of corpus callosum. Our results suggested that white matter of patients with Alzheimer's disease was selectively impaired and the extent of damage had a strong correlation with the cognitive function, and that selective impairment reflected the cortico-cortical and cortico-subcortical disconnections in the pathomechanism of Alzheimer's disease. The values of FA and MD in white matter, especially in the splenium of corpus callosum in AD patients, might be a more appropriate surrogate marker for monitoring the disease progression.