胼胝体压部单发病灶的 MRI 诊断

目的：探讨 MRI 对胼胝体压部单发病灶的诊断价值。方法对9例胼胝体压部单发病灶患者的影像、临床资料及部分患者的随访结果进行回顾性分析、总结。结果(1)临床表现：4例出现头痛、头晕,3例出现一过性晕厥,2例出现发热,2例出现肢体活动障碍。(2)临床诊断：低血糖脑病 3例,1月后复查 MRI 患者病变已吸收消失;脑炎 2例,治疗后好转;脑梗死、癫痫、变性及脑外伤各1例,治疗后病灶仍存在。(3)影像表现：均表现为胼胝体压部单发的类圆形、片状稍长 T1稍长 T2信号影,边界清楚,在扩散加权成像(DWI)上呈高信号,在表观扩散系数(ADC)图为低信号,无明显强化表现。结论多种疾病均可引起胼胝体压部单发病灶,其影像表现相似,其中低血糖脑病及脑炎的影像表现有一定特点(具有可逆性),要明确诊断需结合临床资料及病史。     

Mild encephalopathy with reversible splenium lesion (MERS) in a patient with COVID-19

Neurological complications of coronavirus 2019 (COVID-19) are common, and novel manifestations are increasingly being recognized. Mild encephalopathy with reversible splenium lesion (MERS) is a syndrome that has been associated with viral infections, but not previously with COVID-19. In this report, we describe the case of a 69 year-old man who presented with fever and encephalopathy in the setting of a diffusion-restricting splenium lesion, initially mimicking an ischemic stroke. A comprehensive infectious workup revealed positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies, and a pro-inflammatory laboratory profile characteristic of COVID-19 infection. His symptoms resolved and the brain MRI findings completely normalized on repeat imaging, consistent with MERS. This case suggests that MERS may manifest as an autoimmune response to SARS-CoV-2 infection and should be considered in a patient with evidence of recent COVID-19 infection and the characteristic MERS clinico-radiological syndrome.     

Boomerang sign: Clinical significance of transient lesion in splenium of corpus callosum

Transient signal abnormality in the splenium of corpus callosum on magnetic resonance imaging (MRI) is occasionally encountered in clinical practice. It has been reported in various clinical conditions apart from patients with epilepsy. We describe 4 patients with different etiologies presenting with signal changes in the splenium of corpus callosum. They were diagnosed as having progressive myoclonic epilepsy (case 1), localization-related epilepsy (case 2), hemicrania continua (case 3), and postinfectious parkinsonism (case 4). While three patients had complete involvement of the splenium on diffusion-weighted image (“boomerang sign”), the patient having hemicrania continua showed semilunar involvement (“mini-boomerang”) on T2-weighted and FLAIR image. All the cases had noncontiguous involvement of the splenium. We herein, discuss these cases with transient splenial involvement and stress that such patients do not need aggressive diagnostic and therapeutic interventions. An attempt has been made to review the literature regarding the pathophysiology, etiology, and outcome of such lesions.     

Neuroplasticity of language in left‐hemisphere stroke: Evidence linking subsecond electrophysiology and structural connections

The understanding of neuroplasticity following stroke is predominantly based on neuroimaging measures that cannot address the subsecond neurodynamics of impaired language processing. We combined behavioral and electrophysiological measures and structural‐connectivity estimates to characterize neuroplasticity underlying successful compensation of language abilities after left‐hemispheric stroke. We recorded the electroencephalogram from patients with stroke lesions to the left temporal lobe and from matched controls during context‐driven word retrieval. Participants heard lead‐in sentences that either constrained the final word (“He locked the door with the”) or not (“She walked in here with the”). The last word was shown as a picture to be named. Individual‐participant analyses were conducted, focusing on oscillatory power as a subsecond indicator of a brain region's functional neurophysiological computations. All participants named pictures faster following constrained than unconstrained sentences, except for two patients, who had extensive damage to the left temporal lobe. Left‐lateralized alpha–beta oscillatory power decreased in controls pre‐picture presentation for constrained relative to unconstrained contexts. In patients, the alpha–beta power decreases were observed with the same time course as in controls but were lateralized to the intact right hemisphere. The right lateralization depended on the probability of white‐matter connections between the bilateral temporal lobes. The two patients who performed poorly behaviorally showed no alpha–beta power decreases. Our findings suggest that incorporating direct measures of neural activity into investigations of neuroplasticity can provide important neural markers to help predict language recovery, assess the progress of neurorehabilitation, and delineate targets for therapeutic neuromodulation. Hum Brain Mapp 38:3151–3162, 2017. © 2017 Wiley Periodicals, Inc.     

Regional neuropathology following kainic acid intoxication in adult and aged C57BL/6J mice

We evaluated regional neuropathological changes in adult and aged male mice treated systemically with kainic acid (KA) in a strain reported to be resistant to excitotoxic neuronal damage, C57BL/6. KA was administered in a single intraperitoneal injection. Adult animals were dosed with 35 mg/kg KA, while aged animals received a dose of 20 mg/kg in order to prevent excessive mortality. At time-points ranging from 12 h to 7 days post-treatment, animals were sacrificed and prepared for histological evaluation utilizing the cupric-silver neurodegeneration stain, immunohistochemistry for GFAP and IgG, and lectin staining. In animals of both ages, KA produced argyrophilia in neurons throughout cortex, hippocampus, thalamus, and amygdala. Semi-quantitative analysis of neuropathology revealed a similar magnitude of damage in animals of both ages, even though aged animals received less toxicant. Additional animals were evaluated for KA-induced reactive gliosis, assayed by an ELISA for GFAP, which revealed a 2-fold elevation in protein levels in adult mice, and a 2.5-fold elevation in aged animals. Histochemical evaluation of GFAP and lectin staining revealed activation of astrocytes and microglia in regions with corresponding argyrophilia. IgG immunostaining revealed a KA-induced breach of the blood-brain barrier in animals of both ages. Our data indicate widespread neurotoxicity following kainic acid treatment in C57BL/6J mice, and reveal increased sensitivity to this excitotoxicant in aged animals.     

Morphology of the corpus callosum in human fetuses

Shape and size of the human fetal corpus callosum of a relatively racially homogeneous southern Indian sample population were studied in midsagittal sections of formalin fixed brains. Length of corpus callosum and width of its genu, body, and splenium were measured and the data statistically analyzed. Presence of an isthmus between the body and splenium did not correlate with the measured variables. There was no significant gender difference. The variables correlated significantly among each other but only callosal length and genu width correlated with gestation age. Significant absolute increase occurred in callosal length and genu width, whereas body and splenium widths remained the same. Simple regression equations to estimate the callosal length and genu width for a given age are derived. Clin. Anat. 10:22–26 © 1997 Wiley-Liss, Inc.     

Bright splenium of a psychotic mind

A twenty-one-year old primigravida presented two weeks postpartum with new onset of behavioral alteration and irrelevant talking without fever, headache, or seizures. Magnetic resonance imaging (MRI) of brain showed a lesion with diffusion restriction in splenium of corpus callosum. A possibility of postpartum psychosis was considered after ruling out various etiologies for splenium hyperintense lesion. Near complete resolution of symptoms was noted after initiation of antipsychotic medications. Literature has described multiple etiologies for lesions involving splenium of corpus callosum on brain imaging. We present this case as a unique clinical presentation of splenial pathology in the form of postpartum psychosis.     

可逆性胼胝体压部病变综合征的临床研究进展

可逆性胼胝体压部病变综合征是一种急性单病程的非特异性脑炎/脑病综合征,颅脑MRI显示以胼胝体压部为主的可逆性椭圆形病灶,临床表现多较轻微,可仅表现发热、头痛、呕吐等非典型症状,但也可出现脑实质损害,表现为意识障碍、谵妄、抽搐、共济失调及眩晕,病因与发病机制尚不完全清楚,病程为自限性,短期内可完全恢复,需与累及胼胝体的急性播散性脑脊髓炎等相鉴别,预后良好。