Visual Attention Performances and Related Cerebral Microstructural Integrity Among Subjects With Subjective Cognitive Decline and Mild Cognitive Impairment.

Objective: To compare visual attention performances and diffusion tensor imaging (DTI) between subjects with subjective cognitive decline (SCD) and mild cognitive impairment (MCI), and to discover neuronal substrates related to visual attention performances. Methods: Thirty-nine subjects with SCD and 15 with MCI, diagnosed following neuropsychological tests and conventional brain magnetic resonance imaging, were recruited. All subjects were further examined by the Conners Continuous Performance Test 3 (CPT3) and DTI including fractional anisotropy (FA) and mean diffusivity (MD), in which group comparisons and stepwise linear regression were made. Results: Subjects with MCI had a worse performance in all retrieval indices of verbal/nonverbal memory tests than those with SCD in the context of comparable general cognition and demographic status. In the CPT3, subjects with MCI had a significant longer hit reaction time (HRT) by univariate but not multivariate comparisons. Further analysis suggested that a longer HRT across all interstimuli intervals and at the point of fourth to sixth blocks were noted among MCI subjects. In DTI evaluations, FA value within the left forceps major was the only hotspot with significant between-group differences after the Bonferroni correction of FA and MD values. On the basis that HRT had significant inverse correlations with FA value within the genu of the corpus callosum and left forceps minor, regression analysis was conducted, showing HRT was best predicted by the FA value within the left forceps minor. Area under receiver operative characteristic curve was 0.70; the optimum cut-off for HRT was 515.8 ms, with a sensitivity of 85% but specificity of 47%. Conclusions: Our report suggested that impaired sustained attention and vigilance to be an early cognitive marker in differentiating MCI from SCD, where MCI subjects had a longer HRT across all interstimuli intervals and more profoundly in later blocks. FA measures appeared to be more sensitive DTI parameters than MD values in detecting microstructural changes between SCD and MCI. The role of the anterior interhemispheric fibers in sustained attention implementation during visual signal detection task was highlighted.

Horizontal gaze palsy with progressive scoliosis: a case report with magnetic resonance tractography and electrophysiological study.

BACKGROUND: Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive congenital anomaly characterized by horizontal gaze limitation and progressive scoliosis. We investigated the underlying pathogenesis by incorporating diffusion tensor imaging and an electrophysiological study. CASE PRESENTATION: A 55-year-old female patient presented to our clinic due to a chronic history of eye movement limitation since childhood. Her eye problem was followed by a progressive scoliotic change in her torso during junior high school. Neurological examinations revealed remarkable conjugate horizontal but not vertical gaze palsy. Her pupils were isocoric, with a prompt response to light reflex and convergence. Her vision, including visual acuity and field, were normal. No pathological signs of muscle tone, muscle power, deep tendon reflex or coordination were revealed. There was no associated family history, and no diseases involving other systems were noted. On reviewing her past medical history, X-rays revealed scoliotic changes of her thoracic and lumbar spine. Brain magnetic resonance imaging showed a midline cleavage at the tegmentum (split pons sign) and butterfly configuration of the medulla, consistent with HGPPS. Color-coded diffusion tensor imaging in our patient revealed absence of decussation of the superior cerebellar peduncle. In tractography, the pontocerebellar tracts and fibers within the inferior cerebellar peduncle, deemed to be primarily dorsal spinocerebellar and vestibulocerebellar tracts, appeared to be agenetic. The tegmentum was compromised secondary to dorsal displacement of the corticospinal tracts. Of note, the bilateral corticospinal tracts remained uncrossed at the level presumed to be the pyramidal decussation. A somatosensory evoked potential study also revealed predominantly ipsilateral cortical sensory responses. CONCLUSIONS: Our study confirmed that a compromised tegmentum secondary to dorsal displacement of the corticospinal tracts and poorly-developed afferent fibers within the pontocerebellar tracts and inferior cerebellar peduncle to be the main neuroanatomical anomalies responsible for the clinical presentations of HGPPS. In addition, the uncrossed nature of the majority of pyramidal and proprioceptive sensory systems was confirmed.

ATF4 overexpression induces early onset of hyperlipidaemia and hepatic steatosis and enhances adipogenesis in zebrafish.

Activating transcription factor 4 (ATF4) is constitutively expressed in a variety of tissues, and regulates several pathological features associated with metabolic diseases such as non-alcoholic fatty liver diseases (NAFLD) and obesity. However, the role of ATF4 in animal model systems is poorly understood. To investigate ATF4 functions in zebrafish, we conditionally expressed ATF4 proteins, using a Tet-off transgenic system. We observed early-onset hyperlipidaemia and liver steatosis in ATF4 transgenic zebrafish (ATs) without doxycycline treatment (ATs - Dox). Oil Red O (ORO)-stained signals were predominant in the intravascular blood vessels and liver buds of larval ATs - Dox, indicating that ATF4 functionally promotes lipogenesis. Further, ATF4 overexpression accompanied the stimulation of the unfolded protein response. Therefore, adult ATs - Dox showed increased lipid accumulation, which led, in turn, to liver steatosis. Liver histology and ORO staining of ATs - Dox hepatocytes also indicated oxidative stress and induced NASH-like phenotypes. Moreover, ATF4 overexpression accelerated adipocyte differentiation via CCAAT enhancer binding protein-beta and peroxisome proliferator activated receptor-gamma inducible expression. ATs-Dox zebrafish showed increased weight gain with larger fat pads due to adipocyte hyperplasia. In this study, we report that ATF4 is a potential stimulator of lipid biosynthesis and adipogenesis in zebrafish.

Comparison of neuropsychiatric symptoms and diffusion tensor imaging correlates among patients with subcortical ischemic vascular disease and Alzheimer's disease.

BACKGROUND: The causes of behavioral and psychological symptoms of dementia (BPSD) vary according to the dementia subtype and associated neuropathology. The present study aimed to (i) compare BPSD between patients with subcortical ischemic vascular disease (SIVD) and Alzheimer's disease (AD) across stages, and (ii) explore the associations with diffusion tensor imaging (DTI) in the corpus callosum (CC) and other major fibers. METHODS: Twenty-four patients with SIVD and 32 with AD were recruited. Four domains of the Neuropsychiatric Inventory (NPI) (hyperactivity, psychosis, affective, and apathy) and two DTI parameters [fractional anisotropy (FA) and mean diffusivity (MD)] within the genu, body (BCC), and splenium (SCC) of the CC and other major fibers were assessed. RESULTS: Overall, the patients with clinical dementia rating (CDR) 1 ~ 2 had higher scores in apathy domain than those with CDR0.5. Among those with CDR1 ~ 2, SIVD had higher scores in apathy domain than AD. MD values in the BCC/SCC were positively correlated with total NPI score and psychosis, hyperactivity, and apathy domains. FA values in the SCC were inversely correlated with total NPI score and psychosis domain. The correlations were modified by age, the CASI, and CDR scores. Stepwise linear regression models suggested that FA value within the left superior longitudinal fasciculus predicted the hyperactivity domain. MD value within the SCC/left uncinate fasciculus and FA value within the GCC/left forceps major predicted the psychosis domain. MD value within the right superior longitudinal fasciculus and CDR predicted the apathy domain. Further analysis suggested distinct patterns of regression models between SIVD and AD patients. CONCLUSION: White matter integrity within the BCC/SCC had associations with multi-domains of BPSD. Our study also identified important roles of regions other than the CC to individual domain of BPSD, including the left superior longitudinal fasciculus to the hyperactivity domain, the left uncinate fasciculus/forceps major to the psychosis domain, and the right superior longitudinal fasciculus to the apathy domain. The neuronal substrates in predicting BPSD were different between SIVD and AD patients. Of note, apathy, which was more profound in SIVD, was associated with corresponding fiber disconnection in line with dementia severity and global cognition decline.

Effectiveness of diffusion tensor imaging in differentiating early-stage subcortical ischemic vascular disease, Alzheimer's disease and normal ageing.

OBJECTIVE: To describe and compare diffusion tensor imaging (DTI) parameters between patients with subcortical ischemic vascular disease (SIVD) and Alzheimer's disease (AD) diagnosed using structuralized neuropsychiatric assessments, and investigate potential neuronal substrates related to cognitive performance. METHODS: Thirty-five patients with SIVD, 40 patients with AD, and 33 cognitively normal control (NC) subjects matched by age and education level were consecutively recruited and underwent cognitive function assessments and DTI examinations. Comparisons among these three subgroups with regards to cognitive performance and DTI parameters including fractional anisotropy (FA) and mean diffusivity (MD) values were performed. Partial correlation analysis after controlling for age and education was used to evaluate associations between cognitive performance and DTI parameters. RESULTS: With regards to cognitive performance, the patients with SIVD had lower total scores in frontal assessment battery (FAB) compared to those with AD (p < 0.05) in the context of comparable Mini-Mental Status Examination and Cognitive Abilities Screening Instrument scores. With regards to DTI parameters, there were more regions of significant differences in FA among these three subgroups compared with MD. Compared with NC group, the patients with SIVD had significant global reductions in FA (p < 0.001 ~ 0.05), while significant reductions in FA among the patients with AD were regionally confined within the left superior longitudinal fasciculus, genu and splenium of the corpus callosum, and bilateral forceps major, and the anterior thalamic radiation, uncinate fasciculus, and cingulum of the left side (p < 0.01 ~ 0.05). Analysis of FA values within the left forceps major, left anterior thalamic radiation, and genu of the corpus callosum revealed a 71.8% overall correct classification (p < 0.001) with sensitivity of 69.4%, specificity of 73.8%, positive predictive value of 69.4%, and negative predictive value of 73.8% in discriminating patients with SIVD from those with AD. In combined analysis of the patients with SIVD and AD (n = 75), the total FAB score was positively correlated with FA within the bilateral forceps minor, genu of the corpus callosum, left forceps major, left uncinate fasciculus, and right inferior longitudinal fasciculus (p = 0.001 ~ 0.038), and inversely correlated with MD within the right superior longitudinal fasciculus, genu and body of the corpus callosum, bilateral forceps minor, right uncinate fasciculus, and right inferior longitudinal fasciculus (p = 0.003 ~ 0.040). CONCLUSIONS: Our findings suggest the effectiveness of DTI measurements in distinguishing patients with early-stage AD from those with SIVD, with discernible changes in spatial distribution and magnitude of significance of the DTI parameters. Strategic FA assessments provided the most robust discriminative power to differentiate SIVD from AD, and FAB may serve as an additional cognitive marker. We also identified the neuronal substrates responsible for FAB performance.

Frontal Assessment Battery as a Useful Tool to Differentiate Mild Cognitive Impairment due to Subcortical Ischemic Vascular Disease from Alzheimer Disease.

BACKGROUND: Prominent executive dysfunction can differentiate vascular dementia from Alzheimer disease (AD). However, it is unclear whether the Frontal Assessment Battery (FAB) screening tool can differentiate subcortical ischemic vascular disease (SIVD) from AD at the pre-dementia stage. In addition, the neural correlates of FAB performance have yet to be clarified. METHODS: Patients with mild cognitive impairment (MCI) due to SIVD (MCI-V), MCI due to AD (MCI-A), and demographically matched controls completed the Mini-Mental State Examination, Taiwanese FAB (TFAB), Category Fluency, and Chinese Version of the Verbal Learning Test, and underwent magnetic resonance imaging. White matter hyperintensities were rated according to the Scheltens scale. RESULTS: TFAB total scale and its Orthographical Fluency subtest were the only measures that could differentiate MCI-V from MCI-A. Discriminative analysis showed that Orthographical Fluency scores successfully identified 73.2% of the cases with MCI-V, with 85.0% sensitivity. Orthographical Fluency scores were specifically associated with lesion load within frontal periventricular, frontal deep white matter, and basal ganglia regions. CONCLUSION: The TFAB, and especially its 1-min Orthographical Fluency subtest, is a useful screening procedure to differentiate MCI due to SIVD from MCI due to AD. The discriminative ability is probably due to frontosubcortical white matter pathologies disproportionately involved in the two disease entities.

Tc-99m-ECD SPECT as the measure for therapeutic response in patients with cobalamin deficiency: Two case reports.

BACKGROUND: Cobalamin (Cbl) is an essential vitamin for human health. While an increasing body of evidence supports the negative impact of Cbl deficiency on cognition, the causality has yet to be determined, and the reported therapeutic responses after Cbl supplement therapy have been inconsistent. Besides, few reports have described neuroimaging characteristics associated with the therapeutic response. METHODS: To describe and compare technetium-99m ethyl cysteinate dimer single-photon emission computed tomography (Tc-99m-ECD SPECT) findings in 2 patients with Cbl deficiency with distinct therapeutic responses. RESULTS: Case 1 scored 12/30 in the mini-mental state examination (MMSE) and 34/100 in the cognitive abilities screening instrument (CASI). Profound deficits in mental manipulation, drawing, short-term/long-term memory, and verbal fluency were noted. Case 2 scored 24/30 in the MMSE and 78/100 in the CASI, mainly due to impaired mental manipulation, abstract thinking, and borderline performance in short-term memory and verbal fluency. While both cases showed widespread hypoperfusion within bilateral frontotemporal regions and thalamus on Tc-99m-ECD SPECT, Case 2 demonstrated relatively preserved radio-uptake in the frontal regions, especially the anterior cingulate cortex (ACC) and prefrontal cortex (PFC), consistent with the better therapeutic response (Case 1: 12/30 to 11/30 in the MMSE; Case 2: 24/30 to 28/30 in the MMSE). CONCLUSION: Given that the ACC integrates the limbic system and frontosubcortical circuits and the PFC governs executive function, the extent and severity of hypofrontality may be responsible for the worse prognosis. Our Tc-99m-ECD SPECT observations revealed that the negative impact on cerebral metabolic tone is relevant to the severity of Cbl deficiency, and the functional integrity of the ACC and PFC is highly associated with the preservation of global cognitive function in our cases with Cbl deficiency.

Ischemic stroke in a young patient with Fahr's disease: a case report.

BACKGROUND: Fahr's disease is a rare neurodegenerative disorder characterized by diffuse intracranial calcium deposition and associated cell loss mainly in bilateral basal ganglia and dentate nuclei of the cerebellum. Subarachnoid hemorrhage and epileptic syncope had been reported as acute presentation of Fahr's disease. We here report a 36-year-old male Indonesian diagnosed as Fahr's disease presenting with young-onset ischemic stroke. CASE PRESENTATION: A 36-year-old male Indonesian without prior systemic disease or neurologic disorder presented with young-onset ischemic stroke involving the right posterior limb of internal capsule. Brain computed tomography and magnetic resonance imaging demonstrated symmetric calcifications in bilateral basal ganglia, internal capsules, cerebellar dentate nuclei, thalami, cerebral white matter, which were all consistent with Fahr's disease. The laboratory studies excluded the presence of other pathologic processes leading to secondary intracranial calcification. Other young stroke surveys were unremarkable. After medical treatment and sustained physical rehabilitation for 3 months, he recovered to carry out daily activities independently. CONCLUSION: We present ischemic stroke in a young patient with sporadic Fahr's disease. The differentiation between Fahr's disease and Fahr's syndrome is specially highlighted when brain CT exhibits diffuse, symmetric calcifications in bilateral basal ganglia, thalami, cerebellar dentate nuclei and cerebral white matter. The association between nonarteriosclerotic vascular calcification and cerebrovascular disease is worth special attention and further investigation.

Reversible Changes of Brain Perfusion SPECT for Carbon Monoxide Poisoning-Induced Severe Akinetic Mutism.

PURPOSE: This study aimed to characterize changes in regional cerebral blood flow (rCBF) in patients who experienced carbon monoxide (CO) poisoning and subsequently developed severe delayed neuropsychiatric sequelae (DNS) with akinetic mutism. We determined whether these changes were reversible in parallel with improvements in neuropsychological function in response to treatment, including hyperbaric oxygen therapy. METHODS: Patients who developed severe DNS with akinetic mutism after acute CO intoxication between 2007 and 2011 were enrolled. Tc-ECD brain SPECT findings were compared between the patients with severe akinetic mutism and age-matched control subjects to characterize the pattern of rCBF. Perfusion SPECT was correlated with clinical outcomes after treatment with statistical parametric mapping (SPM8); the height threshold was P < 0.01 at peak level, and the corrected false discovery rate was P < 0.05 at the cluster level. RESULTS: Seven patients with akinetic mutism were analyzed. All patients had neurological symptoms caused by acute CO exposure, and all recovered to nearly normal daily function after initial treatments. In all cases, after a "lucid interval," DNS progressed to akinetic mutism. The SPECT images acquired at the onset of akinetic mutism demonstrated variable hypoperfusion in frontal-temporal-parietal regions, with the greatest severity in the left temporal-parietal regions. In parallel, we performed functional neuropsychiatric tests. After treatment, the brain SPECT showed significantly fewer hypoperfusion regions, and neuropsychiatric tests showed dramatically improved function. CONCLUSIONS: Our findings demonstrated both cerebral cortical and subcortical injuries in patients with CO-induced akinetic mutism. Improvement in rCBF correlated well with functional recovery after treatment.

Vitamin B12 deficiency: Characterization of psychometrics and MRI morphometrics.

OBJECTIVES: Vitamin B12 is essential for the integrity of the central nervous system. However, performances in different cognitive domains relevant to vitamin B12 deficiency remain to be detailed. To date, there have been limited studies that examined the relationships between cognitions and structural neuroimaging in a single cohort of low-vitamin B12 status. The present study aimed to depict psychometrics and magnetic resonance imaging (MRI) morphometrics among patients with vitamin B12 deficiency, and to examine their inter-relations. METHODS: We compared 34 consecutive patients with vitamin B12 deficiency (serum level ≤ 250 pg/ml) to 34 demographically matched controls by their cognitive performances and morphometric indices of brain MRI. The correlations between psychometrics and morphometrics were analyzed. RESULTS: The vitamin B12 deficiency group had lower scores than the controls on total scores of Mini-Mental Status Examination (MMSE) and Cognitive Abilities Screening Instrument (CASI) (both P < 0.05), language (P < 0.01), orientation (P < 0.01), and mental manipulation (P < 0.05). The patients also showed a greater frontal horn ratio than the controls (P < 0.05). Bicaudate ratio, fronto-occipital ratio, uncotemporal index, and normalized interuncal distance all showed a strong correlation with the total score of MMSE and CASI (all P < 0.01). Among these psychometric and morphometric indices, pronounced correlations between bicaudate ratio and long-term memory, mental manipulation, orientation, language, and verbal fluency were noted (all P < 0.01). DISCUSSION: Vitamin B12 deficiency is associated with a global cognition decline with language, orientation, and mental manipulation selectively impaired. Preferential atrophy in frontal regions is the main neuroimaging feature. Although the frontal ratio highlights the relevant atrophy among patients, the bicaudate ratio might be the best index on the basis of its strong association with global cognition and related cognitive domains, implying dysfunction of fronto-subcortical circuits as the fundamental pathogenesis related to vitamin B12 deficiency.

A Case of Multiple System Atrophy with Preexisting Alzheimer's Disease and Predating The Hot Cross Bun Sign.

PURPOSE: Synucleinopathy, tauopathy and amyloidopathy were classified as distinct clinical and pathological entities in traditional classification systems, and their interactions have been studied on neuropathology and molecular genetics recently. CASE REPORT: In this report, we present a 69-year-old male patient who had been diagnosed with probable Alzheimer's disease (AD) dementia due to progressive forgetfulness in February 2013. His Mini- Mental State Examination score was 21/30, and his Cognitive Abilities Screening Instrument score was 78/100, resulted from profound deficits in recent memory and abstract thinking domains. Initial brain magnetic resonance imaging (MRI) showed bilateral medial temporal lobe atrophy but was otherwise unremarkable. He presented with new-onset progressive gait disturbance 18 months after the diagnosis of AD, and mild ataxic gait and linear hyperintensity within the midline of the pons on axial T2-weighted MRI were documented. Neither extrapyramidal nor autonomic signs were observed. Ten months later, profound cerebellar signs, urinary incontinence, and mild axial rigidity consistent with the hot cross bun (HCB) sign were noted. Probable multiple system atrophy-cerebellar (MSA-C) type was finally diagnosed by the clinical and neuroimaging features. Of note, his diagnoses of AD and HCB sign predated the diagnosis of MSA-C by 28 and 10 months, respectively. CONCLUSION: Given that the HCB sign rarely predates overt symptoms or a diagnosis of MSA, we hypothesized that the preexisting amyloidopathy and tauopathy exerted additional neurotoxicity on the synucleinopathy. Key Words: Multiple system atrophy, hot cross bun sign, Alzheimer's disease.

Correlation of Tc-99 m ethyl cysteinate dimer single-photon emission computed tomography and clinical presentations in patients with low cobalamin status.

BACKGROUND: Cobalamin (Cbl) deficiency has been associated with various neuropsychiatric symptoms of different severities. While some studies dedicated in structural neuroimaging credibly address negative impact of low Cbl status, functional imaging reports are limited. We herein retrospectively review the correlation of Tc-99 m ethyl cysteinate dimer single-photon emission computed tomography (Tc-99 m-ECD SPECT) and clinical presentations among patients with low serum cobalamin (Cbl) status (<250 pg/ml). METHODS: Twelve symptomatic patients with low serum Cbl status were enrolled. Clinical presentations, Tc-99 m-ECD SPECT, and neuropsychological tests were reviewed. RESULTS: Dysexecutive syndrome (67 %), forgetfulness (50 %), attention deficits (42 %), and sleep disorders (33 %) constituted the major clinical presentations. All patients (100 %) had temporal hypoperfusion on the Tc-99 m-ECD SPECT. Five patients (42 %) had hypoperfusion restricted within temporal regions and deep nuclei; seven patients (58 %) had additional frontal hypoperfusion. In patients with hypoperfusion restricted within temporal regions and deep nuclei, psychiatric symptoms with spared cognition were their main presentations. Among patients with additional frontal hypoperfusion, six of seven patients (86 %) showed impaired cognitive performances (two of them were diagnosed as having dementia). Among ten patients who finished neuropsychological tests, abstract thinking (70 %) was the most commonly affected, followed by verbal fluency (60 %), short-term memory (50 %), and attention (50 %). Anxiety and sleep problems were the major clinically remarkable psychiatric features (33 % both). Four Tc-99 m-ECD SPECT follow-up studies were available; the degree and extent of signal reversal correlated with cognitive changes after Cbl replacement therapy. CONCLUSIONS: Our TC-99 m-ECD SPECT observations provide pivotal information of neurobiological changes within basal ganglia and fronto-temporal regions in conjunction with disease severity among patients with Cbl deficiency. Hypoperfusion within thalamus/basal ganglia and temporal regions may be seen in the earlier state of Cbl deficiency, when psychiatric symptoms predominate. Hypoperfusion beyond thalamus/basal ganglia and involving frontal regions appears when cognitive problems, mostly dysexecutive syndrome, are manifested. Symmetric hypofrontality of SPECT in the context of dysexcutive syndrome serves as a distinguishing feature of non-amnestic mild cognitive impairment attributed to Cbl deficiency. Concordant with TC-99 m-ECD SPECT findings, the psychiatric symptoms and dysexcutive syndrome undergird impaired limbic and dorsolateral prefrontal circuits originating from basal ganglia respectively.

Utilizing Cerebral Perfusion Scan and Diffusion-tensor MR Imaging to Evaluate the Effect of Hyperbaric Oxygen Therapy in Carbon Monoxide-induced Delayed Neuropsychiatric Seqeulae- A Case Report and Literature Review.

PURPOSE: Detection of regional cerebral blood flow (rCBF) and/or brain magnetic resonance imaging (MRI) has been used to investigate functional defect of brain caused by carbon monoxide (CO) poisoning. In this report, we attempted to demonstrate the correlation of changes in brain singlephoton emission computed tomography (SPECT) and diffusion-tensor MR image (DTI) with functional improvement of severe delayed neuropsychiatric sequelae (DNS) after CO intoxication during the treatment of hyperbaric oxygen therapy (HBOT). CASE REPORT: The patient had normal activities of daily life after he recovered from acute CO poisoning. One month later, he presented symptoms of declined cognitive functioning, aphasia, apraxia, dysphagia, muscle rigidity, urine and fecal incontinence. After one course of HBOT, these symptoms improved significantly and the patient could regain most of his previous functioning. The patient's improvement was evidenced by increased rCBF in Brodmann areas 7, 8, 11 and 40, as well as higher mean fractional anisotropy (FA) value of DTI. CONCLUSION: Although the efficacy of HBOT in DNS patients is still needed to be evaluated in large clinical study, these data suggest that HBOT may be the choice to improve DNS efficiently and shorten the duration of suffering with favorable outcome.

A Rare Case of Painful Trigeminal Neuropathy Secondary to Lateral Medullary Infarct: Neuroimaging and Electrophysiological Studies.

PURPOSE: To report a rare case of painful trigeminal neuropathy after lateral medullary infarct and probe its underlying pathogenesis on the basis of neuroimaging and electrophysiological study. CASE REPORT: A 45-year-old man presented acute onset of unsteady gait followed by paroxysmal and electric shock-like headache in the distribution of ophthalmic branch of left trigeminal nerve in 2 days. Neurological examinations showed hypoesthesia in the distribution of mandibular branch of left trigeminal nerve and left appendicular ataxia. Muscle powers and deep tendon reflexes were normal. Brain magnetic resonance imaging revealed infarct within the left cerebellum and middle portion of dorsolateral medulla. Vascular compression at the root entry zone of trigeminal nerve was excluded. Painful trigeminal neuropathy secondary to lateral medullary infarct was diagnosed. Ancillary blink reflex study 3 days after the stroke event showed abnormal late responses (R2), either ipsilateral or contralateral, after stimulation of left supraorbital nerve, suggesting left medullary lesion. Followup study 3 weeks later demonstrated normalization in absolute latencies of bilateral late responses, in line with remission of pain paroxysms on low-dose gabapentin treatment. CONCLUSION: Painful trigeminal neuropathy attributed to lateral medullary infarct is a unique disease entity. Ophthalmic branch involvement, coexisting sensory deficits, absence of triggers, and rapid evolvement and remission are its characteristics. Our neuroimaging study delineated ischemic stroke pathology within descending tract and spinal nucleus of trigeminal nerve. Serial electrophysiological studies provide evidences supporting ephaptic transmission as the main pathogenesis concordant with dynamics of neuropathic pain and therapeutic implications.

Bortezomib-induced posterior reversible encephalopathy syndrome: clinical and imaging features.

Posterior reversible encephalopathy syndrome (PRES) is a rare and potentially harmful complication in patients receiving targeted chemotherapy. We herein present a case of PRES that occurred after 33 days of high-dose bortezomib treatment and propose both overwhelmed cerebral autoregulation and toxin-mediated blood-brain barrier damage as the underlying mechanisms based on the imaging findings. A favorable recovery was observed two days after achieving stringent hypertension control and withholding bortezomib. Follow-up images obtained two weeks later unveiled a dramatic remission, with faint areas of subcortical hyperintensity in the bilateral parieto-occipital regions. With explicit clinical and imaging features, this case highlights the need for early recognition of PRES during the clinical course of bortezomib therapy.

Comparison of diffusion-weighted imaging and contrast-enhanced T1-weighted imaging on a single baseline MRI for demonstrating dissemination in time in multiple sclerosis.

BACKGROUND: The 2010 Revisions to the McDonald Criteria have established that dissemination in time (DIT) of multiple sclerosis (MS) can be demonstrated by simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions on a single magnetic resonance imaging (MRI). However, gadolinium-based contrast agents (GBCAs) have contraindications. Diffusion-weighted imaging (DWI) can detect diffusion alterations in active inflammatory lesions. The purpose of this study was to investigate if DWI can be an alternative to contrast-enhanced T1-weighted imaging (CE T1WI) for demonstrating DIT in MS. METHODS: We selected patients with clinically definite MS and evaluated their baseline brain MRI. Asymptomatic lesions were identified as either hyperintense or nonhyperintense on DWI and enhancing or nonenhancing on CE T1WI. Fisher's exact test was performed to determine whether the hyperintensity on DWI was related to the enhancement on CE T1WI (P < 0.05). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the DWI to predict lesion enhancement were calculated. RESULTS: Twenty-two patients with 384 demyelinating lesions that were hyperintense on T2-weighted imaging and more than 3 mm in size were recruited. The diffusion hyperintensity and lesion enhancement were significantly correlated (P <0.001). The sensitivity, specificity, PPV, NPV and accuracy were 100%, 67.9%, 32.3%, 100% and 72.1%, respectively. CONCLUSIONS: A hyperintense DWI finding does not necessarily overlap with contrast enhancement. There are many false positives, possibly representing other stages of lesion development. Although DWI may not replace CE T1WI imaging to demonstrate DIT due to the low PPV, it may serve as a screening MRI sequence where the use of GBCAs is a concern.

Comparison of the 2010 and 2005 versions of the McDonald MRI criteria for dissemination-in-time in Taiwanese patients with classic multiple sclerosis.

In 2010, the International Panel on the Diagnosis of Multiple Sclerosis revised the 2005 version of the McDonald criteria. The revisions to MRI dissemination-in-time criteria include adoption of a new criterion by demonstration of simultaneous asymptomatic gadolinium-enhancing and nonenhancing lesions on baseline MRI scans. The purpose of this study was to demonstrate the diagnostic validity of the modified MRI dissemination-in-time criteria. We collected 80 patients with an initial clinical attack suggestive of an acute central nervous system demyelinating disease. The patients were followed for at least two years or until the development of definite multiple sclerosis. The nonconverters were taken as negative cases. Their baseline and follow-up brain MRI studies were retrospectively reviewed by two neuroradiologists. The 2010 version had higher sensitivity (68.2% vs. 45.5%), slightly lower specificity (80.6% vs. 83.3%), and higher accuracy (73.8% vs. 62.5%) than the 2005 version, but the differences were without statistical significance. The new criteria are more sensitive and accurate and specific just as the old criteria. They allow the diagnosis of definite multiple sclerosis in 34.1% patients at first presentation of the clinically isolated syndrome.

Intracerebral hemorrhage following endovascular embolization of brain arteriovenous malformation with a combination of Onyx and n-butyl cyanoacrylate: a case report.

We report a 29-year-old female patient who developed intracerebral hemorrhage 16 h after endovascular embolization of a brain arteriovenous malformation with a combination of liquid embolic agents of Onyx and n-butyl cyanoacrylate. After emergent craniectomy with evacuation of the hematoma, the patient recovered consciousness with mild expressive aphasia. The possible etiology of postembolization brain hemorrhage was discussed, and the literature was reviewed.