DTI correlates of cognition in conventional MRI of normal-appearing brain in patients with clinical features of subacute combined degeneration and biochemically proven vitamin B(12) deficiency

The relationship between nutritional status and white matter integrity in older adults: A diffusion tensor imaging study

OBJECTIVES

The purpose of this study to determinate whether there is a relationship between the nutritional status and white matter integrity in older patients by using Diffusion Tensor Imaging (DTI).

METHODS

The patients were evaluated by Mini-Nutritional Assessment Scale. The patients are categorized in the groups of well-nourished, risk of malnutrition, or malnourished, depending on the overall score> 23.5, 17-23.5, or 17; respectively. All patients had brain MRI and DTI. The mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) values were calculated by ROI-based method in white matter tracts.

RESULTS

Total of the 224 patients; 86 patients had normal nutrition status (group 1), 107 patients were diagnosed with malnutrition risk (group 2) and 31 patients were diagnosed with malnutrition (group 3). Significantly decreased FA values of genu of corpus callosum, forceps minor and significantly increased MD values of middle cerebellar peduncle, and superior frontooccipital fasciculus were detected in group 2 in comparison to group 1 (p < 0.05). After adjusting for the folate and age, MD and RD values of cingulum remained significantly higher and the AD values of superior cerebellar peduncle remained significantly lower in group 3 (p < 0.05).

CONCLUSIONS

Malnutrition was associated with deteriorated DTI values, especially in cingulum and superior cerebellar peduncle. Assessing the nutritional status of older individuals is crucial to avoid its negative impact on brain.

ADVANCES IN KNOWLEDGE

Early diagnosis of malnutrition-related impaired WM integrity is important for prevention and intervention, and DTI is a useful non-invasive technique to be used for this purpose.

Diagnosis, Treatment and Long-Term Management of Vitamin B12 Deficiency in Adults: A Delphi Expert Consensus

Background/Objectives: Vitamin B12 deficiency can cause variable symptoms, which may be irreversible if not diagnosed and treated in a timely manner. We aimed to develop a widely accepted expert consensus to guide the practice of diagnosing and treating B12 deficiency. Methods: We conducted a scoping review of the literature published in PubMed since January 2003. Data were used to design a two-round Delphi survey to study the level of consensus among 42 experts. Results: The panelists agreed on the need for educational and organizational changes in the current medical practices for diagnosing and treating B12 deficiency. Recognition of clinical symptoms should receive the highest priority in establishing the diagnosis. There is agreement that the serum B12 concentration is useful as a screening marker and methylmalonic acid or homocysteine can support the diagnosis. Patient lifestyle, disease history, and medications can provide clues to the cause of B12 deficiency. Regardless of the cause of the deficiency, initial treatment with parenteral B12 was regarded as the first choice for patients with acute and severe manifestations of B12 deficiency. The use of high-dose oral B12 at different frequencies may be considered for long-term treatment. Prophylactic B12 supplementation should be considered for specific high-risk groups. Conclusions: There is a consensus that clinical symptoms need to receive more attention in establishing the diagnosis of B12 deficiency. B12 laboratory markers can support the diagnosis. The severity of clinical symptoms, the causes of B12 deficiency, and the treatment goals govern decisions regarding the route and dose of B12 therapy.

Evaluation of white matter integrity by diffusion tensor imaging in the deficiencies of vitamin B12 and folate in older patients

OBJECTIVES

The aim of this study is to investigate whether white matter (WM) integrity is impaired in vitamin B12 and folate deficiency with Diffusion Tensor Imaging (DTI) in older patients.

METHODS

All the patients aged ≥65 years admitted to the geriatric clinic and performed DTI-MRI were included in the study. DTI parameters (fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity) were calculated by ROI-based method in white matter tracts. Deficiency threshold for vitamin B12 were defined as <200 pg ml-1 and <400 pg ml-1 separately; and for folate as <3 ng ml-1 and <6 ng ml-1, separately.

RESULTS

DTI was performed to older patients having serum vitamin B12 level (n = 106, mean age = 80.7±7.7, 66% female) and folate level (n = 101, mean age = 80.7±7.5, 67.3% female). Significantly lower FA and higher MD and RD levels were observed in multiple WM areas including superior and middle cerebellar peduncles, cingulum and genu of corpus callosum in patients with vitamin B12 <400 pg ml-1 (p < 0.05). DTI indices also showed significant changes in the genu of corpus callosum, and right and left superior longitudinal fasciculus in patients with folate <6 ng ml-1 (p < 0.05).

CONCLUSIONS

Deficiencies of vitamin B12 and folate may be associated with impaired white matter integrity in elderly even at high laboratory levels, and DTI is a useful method to detect it.

ADVANCES IN KNOWLEDGE

Early detection of impaired WM integrity caused by micronutrient deficiencies poses a great significance in terms of prevention and intervention, and DTI is an effective non-invasive method to be used for this purpose.

Mapping the rest of the human connectome: Atlasing the spinal cord and peripheral nervous system

The emergence of diffusion, structural, and functional neuroimaging methods has enabled major multi-site efforts to map the human connectome, which has heretofore been defined as containing all neural connections in the central nervous system (CNS). However, these efforts are not structured to examine the richness and complexity of the peripheral nervous system (PNS), which arguably forms the (neglected) rest of the connectome. Despite increasing interest in an atlas of the spinal cord (SC) and PNS which is simultaneously stereotactic, interactive, electronically dissectible, scalable, population-based and deformable, little attention has thus far been devoted to this task of critical importance. Nevertheless, the atlasing of these complete neural structures is essential for neurosurgical planning, neurological localization, and for mapping those components of the human connectome located outside of the CNS. Here we recommend a modification to the definition of the human connectome to include the SC and PNS, and argue for the creation of an inclusive atlas to complement current efforts to map the brain's human connectome, to enhance clinical education, and to assist progress in neuroscience research. In addition to providing a critical overview of existing neuroimaging techniques, image processing methodologies and algorithmic advances which can be combined for the creation of a full connectome atlas, we outline a blueprint for ultimately mapping the entire human nervous system and, thereby, for filling a critical gap in our scientific knowledge of neural connectivity.

Subacute combined degeneration of the cervical and dorsal spinal cord in a 40-year-old male patient: A case report

Subacute combined degeneration of the spinal cord is a neurologic complication of vitamin B12 deficiency. It presents as a potentially reversible demyelination of the posterior and lateral columns of the cervical and dorsal spinal cord. We present the case of a 40-year-old male with progressive sensory and motor deficit from the lower extremities ascending to the mid-thoracic region. A combination of laboratory tests and magnetic resonance imaging confirmed the diagnosis of subacute degeneration of the spinal cord due to vitamin B12 deficiency.

Vitamin B-12 Supplementation during Pregnancy and Early Lactation Does Not Affect Neurophysiologic Outcomes in Children Aged 6 Years

BACKGROUND

Deficiency of vitamin B-12 is common in pregnant Indian women. Assessment of neurophysiological measures using event-related potentials (ERPs) may yield additional information on the effects of maternal B-12 supplementation on child brain function.

OBJECTIVES

The objective of the study was to evaluate the effects of vitamin B-12 supplementation (50 μg daily orally) during pregnancy on the childhood ERP measures of positive waveform ∼300 ms after stimulus (P300) and mismatch negativity.

METHODS

This study was a follow-up of children born to pregnant women who received oral vitamin B-12 supplements (n = 62) compared with children of pregnant women who received placebo (n = 70) from a randomized controlled trial. The mean ± SD child age was 72 ± 1 mo. We used the Enobio system to assess the ERP measures P300 and mismatch negativity.

RESULTS

There were no significant differences in the primary outcomes, amplitudes, and latencies of the P300 results and the mismatch negativity between children in the supplementation and placebo groups. We combined the intervention and placebo groups for secondary analyses. On multiple variable regression analysis after adjusting for treatment group, intrauterine growth restriction, and home environment, P300 amplitude in children was significantly higher in the lowest tertile of third-trimester maternal methylmalonic acid (MMA) concentrations (β = 3034.04; 95% CI: 923.24, 5144.83) compared with the highest MMA tertile (β = 1612.12; 95% CI: -258.86, 3483.10, P = 0.005).

CONCLUSIONS

While no significant effects of maternal vitamin B-12 supplementation on children's ERP measures were seen at 72 mo, elevated maternal MMA concentrations in the third trimester were negatively associated with P300 amplitude in children. It may be worthwhile to study the impact of maternal and infant vitamin B-12 supplementation on childhood brain structure and function in longer and larger trials. The parent trial was registered at clinicaltrials.gov as NCT00641862.

Brain Circuit Alterations and Cognitive Disability in Late-Onset Cobalamin D Disorder

Neuroimaging studies describing brain circuits' alterations in cobalamin (vitamin B12)-deficient patients are limited and have not been carried out in patients with inborn errors of cobalamin metabolism. The objective of this study was to assess brain functionality and brain circuit alterations in a patient with an ultra-rare inborn error of cobalamin metabolism, methylmalonic aciduria, and homocystinuria due to cobalamin D disease, as compared with his twin sister as a healthy control (HC). We acquired magnetic resonance imaging (including structural, functional, and diffusion images) to calculate brain circuit abnormalities and combined these results with the scores after a comprehensive neuropsychological evaluation. As compared with HC, the patient had severe patterns of damage, such as a 254% increment of ventricular volume, pronounced subcortical and cortical atrophies (mainly at striatum, cingulate cortex, and precuneus), and connectivity alterations at fronto-striato-thalamic circuit, cerebellum, and corpus callosum. In agreement with brain circuit alterations, cognitive deficits existed in attention, executive function, inhibitory control, and mental flexibility. This is the first study that provides the clinical, genetic, neuroanatomical, neuropsychological, and psychosocial characterization of a patient with the cobalamin D disorder, showing functional alterations in central nervous system motor tracts, thalamus, cerebellum, and basal ganglia, that, as far as we know, have not been reported yet in vitamin B12-related disorders.

Rationalization of Using the MR Diffusion Imaging in B12 Deficiency

Context:

The structural imaging of brain does not demonstrate any changes in the vast majority of patients with vitamin B12 deficiency, even in the advanced stages.

Aims:

We investigated the microstructural changes in the brain with diffusion imaging among patients with biochemical evidence of B12 deficiency.

Patients and Methods:

We retrospectively analyzed all diffusion-weighted MRI images between the periods 2014–2016 who had biochemical evidence of B12. The age-sex matched controls were chosen from the group with normal B12 levels. Patients with pathological findings in conventional MRI images were excluded from the study.

Results:

About 37 patients were recruited (22 women, 15 men; mean age, 34.1 ± 9.9 years; age range). They were about thirty-four age-and sex-matched controls (with normal B12 levels), which were also included in the study. The mean apparent diffusion coefficient (ADC) value of amygdala (773.8 ± 49.9 vs. 742.2 ± 24.2, P = 0.01), hypothalamus (721.3 ± 39.2 vs. 700.2 ± 38.2, P = 0.02), striate cortex (737.6 ± 77.6 vs. 704.3 ± 58.2, P = 0.04), suprafrontal gyrus (740.7 ± 46.9 vs. 711.6 ± 40.7, P = 0.007) and medulla oblongata-olivary nucleus (787.3 ± 56.4 vs. 759.7 ± 46.2, P = 0.02) were significantly higher in B12 deficiency group compared to controls, whereas ADC values were similar at hippocampus, thalamus, insula, corpus striatum, cingulate gyrus, occipital gyrus, dentate nucleus, cerebral pedicle, tegmentum, pons, and posterior medulla oblongata.

Conclusions:

Our study indicates that a significant increase in ADC values occurs in multiple brain regions in patients with vitamin B12.

Rare anterior funiculus lesions in subacute combined degeneration of the spinal cord: a case report and literature review

Objective: Anterior funiculus lesion is uncommon in subacute combined degeneration of the spinal cord with few data available. Aim of the study was to describe a case with the rare manifestation and summarize existing literatures.Methods: We report a case of a 42-year-old woman with anterior and lateral funiculus lesions on cervicothoracic spine magnetic resonance imaging, who presented with unsteady gait, sensory level and weakness of lower limbs. Besides, we reviewed and analyzed literatures about subacute combined degeneration of the spinal cord with anterior funiculus lesions published during the past two decades.Results: The diagnosis of subacute combined degeneration of the spinal cord was considered due to her presence of low serum vitamin B12 levels, pernicious anemia and gastric carcinoid.Conclusion: Physicians should consider subacute combined degeneration of the spinal cord as a possible differential diagnosis when faced with atypical lesions distributed in the anterior funiculus.

A physiological dose of oral vitamin B-12 improves hematological, biochemical-metabolic indices and peripheral nerve function in B-12 deficient Indian adolescent women

BACKGROUND

Vitamin B-12 deficiency is often considered synonymous with pernicious anemia, a rare condition in which severe malabsorption of the vitamin requires high-dose parenteral treatment. In developing countries such as India, inadequate dietary intake of B-12 due to socio-cultural factors leads to widely prevalent asymptomatic low B-12 status. In this scenario, lower doses of oral B-12 may be effective, safer and more affordable.

OBJECTIVE

To examine the effects of oral B-12 treatment at physiological doses on hematological and biochemical indices and peripheral nerve function in B-12 deficient rural Indian adolescent women.

METHODS

Thirty-nine women with B-12 deficiency who were excluded from a community based B-12 supplementation trial (Pune Rural Intervention in Young Adolescents (PRIYA)) received oral B-12 2μg/day, either alone (n = 19) or with multiple micronutrients (UNIMAPP formula + 20gm milk powder, n = 20) for 11 months. Hematological indices, nutrients (B-12, folate), metabolites (homocysteine) and peripheral nerve function (SUDOSCAN, Impetomedical, Paris and sensory nerve conduction velocity (NCV) of median and sural nerves) were assessed at baseline and after 11 months of B-12 treatment.

RESULTS

Results were similar in the two treatment allocation groups, which were therefore combined. At baseline, all women had B-12 concentration <100pmol/L, 79% were anemic and 33% had macrocytosis, but none had neuropathy. After 11 months of treatment, B-12 levels increased, while folate did not change. The prevalence of anemia fell to 59% and mean corpuscular volume (MCV) and plasma homocysteine concentrations decreased. Sudomotor nerve function in the feet improved by an average of 14.7%, and sensory conduction velocity in median and sural nerves increased by 16.2% and 29.4% respectively.

CONCLUSION

We document clinically beneficial effects of supplementation with a physiological dose of oral B-12 in asymptomatic rural Indian adolescent women with very low B-12 status. These findings support a public health approach to tackle the widely prevalent low B-12 status in young Indians.

Brain Hemodynamic Intermediate Phenotype Links Vitamin B12 to Cognitive Profile of Healthy and Mild Cognitive Impaired Subjects

Vitamin B₁₂, folate, and homocysteine are implicated in pivotal neurodegenerative mechanisms and partake in elders' mental decline. Findings on the association between vitamin-related biochemistry and cognitive abilities suggest that the structural and functional properties of the brain may represent an intermediate biomarker linking vitamin concentrations to cognition. Despite this, no previous study directly investigated whether vitamin B₁₂, folate, and homocysteine levels are sufficient to explain individual neuropsychological profiles or, alternatively, whether the activity of brain regions modulated by these compounds better predicts cognition in elders. Here, we measured the relationship between vitamin blood concentrations, scores at seventeen neuropsychological tests, and brain activity of sixty-five elders spanning from normal to Mild Cognitive Impairment. We then evaluated whether task-related brain responses represent an intermediate phenotype, providing a better prediction of subjects' neuropsychological scores, as compared to the one obtained considering blood biochemistry only. We found that the hemodynamic activity of the right dorsal anterior cingulate cortex was positively associated (p value < 0.05 cluster corrected) with vitamin B₁₂ concentrations, suggesting that elders with higher B₁₂ levels had a more pronounced recruitment of this salience network region. Crucially, the activity of this area significantly predicted subjects' visual search and attention abilities (p value = 0.0023), whereas B₁₂ levels per se failed to do so. Our results demonstrate that the relationship between blood biochemistry and elders' cognitive abilities is revealed when brain activity is included into the equation, thus highlighting the role of brain imaging as intermediate phenotype.

Conventional and quantitative MRI in a novel feline model of demyelination and endogenous remyelination

BACKGROUND

The feeding of irradiated food to healthy adult cats results in widespread, noninflammatory demyelination of the central nervous system (CNS); a return to a normal diet results in endogenous remyelination with functional recovery. This recently discovered, reversible disease might provide a compelling clinical neuroimaging model system for the development and testing of myelin-directed MRI methods as well as future remyelination therapies.

PURPOSE

Identify the noninvasive imaging characteristics of this new disease model and determine whether it features measurable changes on conventional and quantitative MRI.

STUDY TYPE

Pilot study.

ANIMAL MODEL

Ten adult cats at various stages of demyelinating disease induced by an irradiated diet (35-55 kGy), and during recovery following a return to a normal diet.

FIELD STRENGTH/SEQUENCE

Conventional (T2 -weighted) and quantitative (diffusion tensor, magnetization transfer) at 3T.

ASSESSMENT

MRI of the brain, optic nerves, and cervical spinal cord; a subset of diseased cats was euthanized for comparative histopathology.

STATISTICAL TESTS

Descriptive statistics.

RESULTS

Disease produced T2 prolongation, progressing from patchy to diffuse throughout most of the cerebral white matter (eventually involving U-fibers) and spinal cord (primarily dorsal columns, reminiscent of subacute combined degeneration but without evidence of B12 deficiency). Magnetization transfer parameters decreased by 50-53% in cerebral white matter and by 25-30% in optic nerves and spinal cord dorsal columns. Fractional diffusion anisotropy decreased by up to 20% in pyramidal tracts, primarily driven by increased radial diffusivity consistent with axon preservation. Histopathology showed scattered myelin vacuolation of major white matter tracts as well as many thin myelin sheaths consistent with remyelination in the recovery phase, which was detectable on magnetization transfer imaging.

DATA CONCLUSION

Feline irradiated diet-induced demyelination features noninvasively imageable and quantifiable demyelination and remyelination of the CNS. It is therefore a compelling clinical neuroimaging model system.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1304-1311.

Evaluation of diffusion tensor imaging changes and neurocognitive effects of asymptomatic vitamin B12 deficiency

Vitamin B12 plays an important role in the mechanisms which are responsible for myelinization in the central nervous system. It can particularly lead to hematological and neuropsychiatric symptoms when serum levels fall due to insufficient intake with diet or absorption problems. The purpose of this study was to show the cognitive effects in vitamin B12 deficiency cases that have not reached clinical symptom level using neuropsychological tests, and to show possible cerebral neuronal damage using diffusion tensor imaging (DTI) method. A total of 62 asymptomatic vitamin B12 deficiency patients and 40 healthy subjects were included in the study and both groups were subjected to Standardized Mini-Mental State Examination, Montreal Cognitive Assessment Test, Rey Auditory Verbal Learning Test, forward and backward digit span (WMS-R forward and backward), Visual Reproduction Subtest (WMS-III), Category Fluency Test, Trail Making (Trail A-B) (21) and Similarities (BENZ) tests. DTI examinations were performed on both groups. Patient group was determined to get lower scores in all neuropsychological tests compared to control group. In DTI examination, a significant decrease in FA values of bilateral hippocampus and a prominent increase in apparent diffusion coefficient (ADC) values were determined in the patient group compared to control group. In this study, it was determined that there was microstructural damage in the brain in the presence of vitamin B12 deficiency even in the asymptomatic period, and the patients revealed cognitive decline. In accordance with this result, early treatment of the easily diagnosed and treated vitamin B12 deficiency may prevent possible irreversible damage in the future.

Subacute Combined Degeneration: A Retrospective Study of 68 Cases with Short-Term Follow-Up

PURPOSE

The study aimed to analyze the clinical characteristics, laboratory test results, neuroimaging findings, and outcomes in patients diagnosed with subacute combined degeneration (SCD).

MATERIALS AND METHODS

A total of 68 patients with SCD who had been appropriately treated for no less than 6 months were included in our study. Histories, results of routine blood tests, biochemical indices, serum vitamin B12 levels, and spinal magnetic resonance imaging (MRI) findings from the patients were studied and analyzed. Clinical signs and symptoms, graded using a functional disability rating scale, were scored at the time of admission and 3 and 6 months after admission.

RESULTS

Limb numbness, limb weakness, and gait disturbances were the most common symptoms in patients with SCD. All patients showed clinical improvement to different degrees at the follow-up visits after vitamin B12 treatment. No differences in rating score were found in patients grouped by sex, hemoglobin level, serum vitamin B12, or MRI manifestations at the time of admission or at the follow-up visits. Younger patients and those with shorter disease courses had better rating scores at the short-term follow-up visits.

CONCLUSION

Anemia, low levels of serum vitamin B12, and MRI abnormalities in the spinal cord are not expected to be associated with worse clinical manifestations. The age of onset and course of disease are important in evaluating the short-term prognosis of patients with SCD.

Vitamin B12

The biosynthesis of B₁₂, involving up to 30 different enzyme-mediated steps, only occurs in bacteria. Thus, most eukaryotes require an external source of B₁₂, and yet the vitamin appears to have only two functions in eukaryotes: as a cofactor for the enzymes methionine synthase and methylmalonylCoA mutase. These two functions are crucial for normal health in humans, and in particular, the formation of methionine is essential for providing methyl groups for over 100 methylation processes. Interference with the methionine synthase reaction not only depletes the body of methyl groups but also leads to the accumulation of homocysteine, a risk factor for many diseases. The syndrome pernicious anemia, characterized by lack of intrinsic factor, leads to a severe, sometimes fatal form of B₁₂ deficiency. However, there is no sharp cutoff for B₁₂ deficiency; rather, there is a continuous inverse relationship between serum B₁₂ and a variety of undesirable outcomes, including neural tube defects, stroke, and dementia. The brain is particularly vulnerable; in children, inadequate B₁₂ stunts brain and intellectual development. Suboptimal B₁₂ status (serum B₁₂<300pmol/L) is very common, occurring in 30%-60% of the population, in particular in pregnant women and in less-developed countries. Thus, many tens of millions of people in the world may suffer harm from having a poor B₁₂ status. Public health steps are urgently needed to correct this inadequacy.

Vitamin B-12 concentration, memory performance, and hippocampal structure in patients with mild cognitive impairment

BACKGROUND

Low-normal concentrations of vitamin B-12 (VitB12) may be associated with worse cognition. However, previous evidence has been mixed, and the underlying mechanisms remain unclear.

OBJECTIVE

We determined whether serum VitB12 concentrations within the normal range were linked to memory functions and related neuronal structures in patients with mild cognitive impairment (MCI).

DESIGN

In a cross-sectional design, we assessed 100 amnestic MCI patients (52 women; age range: 50-80 y) with low- and high-normal VitB12 concentration (median split: 304 pmol/L) for memory functions with the use of the Auditory Verbal Learning Test. MRI was performed at 3 tesla (n= 86) for the estimation of the volume and microstructure of the hippocampus and its subfields as indicated by the mean diffusivity on diffusion-weighted images. With the use of a mediation analysis, we examined whether the relation between VitB12 and memory performance was partially explained by volume or microstructure.

RESULTS

MCI patients with low-normal VitB12 showed a significantly poorer learning ability (P= 0.014) and recognition performance (P= 0.008) than did patients with high-normal VitB12. Also, the microstructure integrity of the hippocampus was lower in patients with low-normal VitB12, mainly in the cornu ammonis 4 and dentate gyrus region (P= 0.029), which partially mediated the effect of VitB12 on memory performance (32-48%). Adjustments for age, sex, education, apolipoprotein E e4 status, and total homocysteine, folate, and creatinine did not attenuate the effects.

CONCLUSIONS

Low VitB12 concentrations within the normal range are associated with poorer memory performance, which is an effect that is partially mediated by the reduced microstructural integrity of the hippocampus. Future interventional trials are needed to assess whether supplementation of VitB12 may improve cognition in MCI patients even in the absence of clinically manifested VitB12 deficiency. This trial was registered at clinicaltrials.gov as NCT01219244.

Assessment of brain cognitive functions in patients with vitamin B12 deficiency using resting state functional MRI: A longitudinal study

INTRODUCTION

The resting state functional MRI (rsfMRI) approach is useful to explore the brain's functional organization in health and disease conditions. In this study, using rsfMRI the alteration in brain due to vitamin B12 deficiency and reversibility of these alterations following therapy was studied.

METHODS

Thirteen patients with clinical and biochemical evidence of vitamin B12 deficiency were recruited in this study. Fifteen age and sex matched healthy controls were also included. Patients and controls were clinically evaluated using neuropsychological test (NPT). The analysis was carried out using regional homogeneity (ReHo) and low frequency oscillations (LFO) of BOLD signals in resting state. Six patients were also evaluated with rsfMRI and NPT after 6 weeks replacement therapy.

RESULTS

ReHo values in patients with vitamin B12 deficiency were significantly lower than controls in the entire cerebrum and the brain networks associated with cognition control, i.e., default mode, cingulo-opercular and fronto-parietal network. There was no significant difference using LFO and it did not show significant correlations with NPT scores. ReHo showed significant correlation with NPT scores. All the 6 patients showed increase in ReHo after replacement therapy.

CONCLUSION

We conclude that brain networks associated with cognition control are altered in patients with vitamin B12 deficiency, which partially recover following six weeks of replacement therapy. This is the first study to evaluate the rsfMRI in the light of clinical neuropsychological evaluation in patients. rsfMRI may be used as functional biomarker to assess therapeutic response in vitamin B12 deficiency patients.

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.

Assessment of functional and structural damage in brain parenchyma in patients with vitamin B12 deficiency: A longitudinal perfusion and diffusion tensor imaging study

INTRODUCTION

Vitamin B12 deficiency may cause neural tissue damage. Even in advanced stages, conventional imaging of brain usually appears normal in vitamin B12 deficient patients. The aim of this study was to assess the structural and functional changes in brain of patients with vitamin B12 deficiency before and after six weeks of vitamin B12 supplementation using diffusion tensor imaging and pseudo-continuous arterial spin labelling (PCASL).

METHODS

MR imaging including DTI and PCASL and neuropsychological tests (NPT) were performed in 16 patients with vitamin B12 deficiency and 16 controls before and after 6weeks of therapy. Cerebral blood flow (CBF) derived from PCASL and DTI indices was calculated in brain of patients with vitamin B12 deficiency and controls.

RESULTS

Patient with vitamin B12 deficiency showed altered neuropsychological scores and altered CBF as well as fractional anisotropy (FA) values in various brain regions as compared with controls. Both CBF values and neuropsychological scores showed complete reversibility at 6weeks post therapy. Though FA values showed significant recovery, it failed to show complete recovery.

CONCLUSION

Our results suggest that micro-structural recovery lags behind functional recovery in patients with vitamin B12 deficiency following therapy and CBF change may be used as an early predictor of complete recovery in patients with B12 deficiency.