Clinical findings of hyperechoic substantia nigra in patients with Parkinson's disease

This study aims to analyse hyperechoic substantia nigra (HSN) characteristics and the correlation of HSN with clinical features and blood biomarkers in patients with Parkinson's disease (PD). Transcranial sonography (TCS) evaluations of the substantia nigra (SN) were performed in 40 healthy controls and 71 patients with PD, including patients with SN hyperechogenicity (SN+) and those with normal SN echogenicity (SN-). Evaluation of motor and non-motor symptoms was assessed by a series of rating scales. The uricase method was used to determine serum uric acid (UA) levels, and enzyme-linked immunosorbent assay (ELISA) was used to measure plasma interleukin (IL)-1β levels. TCS showed 92.50% specificity and 61.97% sensitivity in differentiating PD patients from controls. The area of SN+ contralateral to the side of initial motor symptoms (SNcontra) was larger than that ipsilateral to the side of initial motor symptoms (SNipsi). The PDSN+ group had lower Argentine Hyposmia Rating Scale (AHRS) scores and UA levels than the PDSN- group. Binary logistic regression analysis revealed that AHRS scores and UA levels could be independent predictors for HSN. The larger SN echogenic area (SNL) sizes positively correlated with plasma IL-1β levels in PD patients with SN+. The present study provides further evidence of the potential of SN echogenicity as an imaging biomarker for PD diagnosis. PD patients with HSN have more severe non-motor symptoms of hyposmia. HSN in PD patients is related to the mechanism of abnormal iron metabolism and microglial activation.

Kidney R2* Mapping for Noninvasive Evaluation of Iron Overload in Paroxysmal Nocturnal Hemoglobinuria

PURPOSE

The kidney iron deposition can cause kidney damage and renal insufficiency in paroxysmal nocturnal hemoglobinuria (PNH) patients. Assessment of iron deposition in the kidney is essential for the early diagnosis of renal damage in PNH patients. The purpose of this study was to evaluate kidney R2* (T2* reciprocals) values in PNH patients using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ).

METHODS

Two radiologists measured the R2* values of the renal cortex in 14 PNH patients and 13 healthy volunteers using IDEAL-IQ. Lactate dehydrogenase (LDH), a reliable marker of intravascular hemolysis, was also measured in all participants.

RESULTS

The kidney R2* values were significantly higher in PNH patients compared with those in healthy volunteers (P < 0.001). High inter-operator reproducibility of the measurements was also acquired using IDEAL-IQ. LDH levels were also significantly higher in PNH patients compared with those in healthy volunteers (P < 0.001). Kidney R2* values strongly correlated with LDH levels in PNH patients.

CONCLUSION

IDEAL-IQ has a possibility of becoming a useful method for the noninvasive evaluation of renal iron overload in PNH patients.

Increased Brain Iron Deposition in Episodic Migraine: A Pilot Voxel-based Quantitative Susceptibility Mapping

INTRODUCTION

Although iron deposition has been identified as a significant migraine trigger, the key structures in episodic migraine (EM) remain unknown.

OBJECTIVE

The aim of this study is to investigate cerebral iron deposition in EM using an advanced voxel-based quantitative susceptibility mapping (QSM).

METHODS

A multi-echo gradient echo sequence MR was performed in 15 episodic migraine patients (EMs) and 27 normal control subjects (NCs). The reconstructed quantitative susceptibility mapping images and voxel-based analysis were performed over the entire brain. The susceptibility value of all brain regions with altered iron deposition was extracted, and the correlations between susceptibility value and clinical variables (including HAMA, HAMD, MoCA, VAS, MIDAS score, diseased duration, and headache frequency) were calculated.

RESULTS

EM patients presented increased susceptibility value in the left putamen and bilateral substantia nigra (SN) compared with NC. There was no correlation between susceptibility value and the clinical variables.

CONCLUSION

Increased brain iron deposition in the extrapyramidal system may be a biomarker for migraine, and abnormal iron metabolism may be involved in the extrapyramidal mechanism. The QSM technique would be an optimal and simple tool for clinical practice and research in iron measurement.

Correlation of brain iron deposition and freezing of gait in Parkinson's disease: a cross-sectional study

Background

Quantitative susceptibility mapping (QSM) is a novel imaging method for detecting iron content in the brain. The study aimed determine whether the iron deposition in the brains of people with Parkinson's disease (PD) is correlated with freezing of gait (FOG).

Methods

We retrospectively collected the data of 24 patients with PD from the Movement Disorders Program and 36 healthy controls (HCs) from January 2021 to December 2021. Clinical assessments included mental intelligence scales, Parkinson rating scales, motor-related scales, and clinical gait assessments. All exercise scales and gait assessments were performed in the "ON" and "OFF" states. Magnetic resonance imaging (MRI) data were collected using 3-dimensional fast low-angle shot sequences. We chose the bilateral red nucleus, substantia nigra, thalamus, putamen, caudate nucleus, and globus pallidus as regions of interest for QSM analysis.

Results

The iron deposition in the substantia nigra of the PD group was significantly higher than that of the HC group (P<0.01). In the PD group, the iron deposition in the substantia nigra of patients with FOG was significantly higher than that in patients without FOG (P=0.04). The iron deposition in the substantia nigra was positively correlated with the New Freezing of Gait Questionnaire (P=0.03). The scores for depression and anxiety of the PD group were significantly higher than those of the HC group, while the Berg balance scale score was significantly lower (P<0.01).

Conclusions

The iron deposition in the substantia nigra of patients with PD is increased compared with that of controls and is associated with FOG. QSM can be used to detect brain iron deposition in patients with PD, which would help to explore the mechanism of abnormal neurobiological activity in FOG.

[Brain iron deposition increases in the bilateral substantia nigra of patients with medication-overuse headache: a quantitative susceptibility mapping analysis]

OBJECTIVE

To investigate iron accumulation level over the whole brain and explore the possible neuromechanism of medication-overuse headache (MOH) using quantitative susceptibility mapping (QSM).

METHODS

Thirty-seven MOH patients and 27 normal control subjects were enrolled in the study for examinations with both a multiecho gradient echo magnetic resonance (MR) sequence and brain high resolution structural imaging. A voxel-based analysis was performed to detect the brain regions with altered iron deposition, and the quantitative susceptibility mapping values of the positive brain regions were extracted. Correlation analysis was performed between the susceptibility values and the clinical variables of the patients.

RESULTS

In patients with MOH, increased susceptibility values were found mainly in the bilateral substantia nigra (SN) (MNI coordinate: 8, -18, -14; -6, -16, -14) as compared with the normal control subjects (P < 0.001), but these alterations in iron deposition were not significantly correlated with the clinical variables of the patients (P > 0.05). The susceptibility value in the left SN had an area under curve (AUC) of 0.734, and at the cut-off value of 0.077, its diagnostic sensitivity was 72.97% and its specificity was 70.37% for distinguishing MOH from normal controls; The susceptibility value in the right SN had an AUC of 0.699 with a diagnostic sensitivity of 72.97% and a specificity of 62.96% at the cut-off value of 0.084.

CONCLUSION

Increased iron deposition occurs in the bilateral SN of MOH patients, which provides a new insight into the mechanism of mesocorticolimbic dopamine system dysfunction in MOH. QSM technique can be used as a non-invasive means for quantitative analysis of brain iron deposition in migraine neuroimaging.

A case report of superficial siderosis of the central nervous system and literature review

Superficial siderosis of the central nervous system (SSCNS) is a rare disease characterized by iron deposition on the tissue surface of the middle axis system. We report the case of a man in his late 40 s who was admitted to the hospital with ataxia. A physical examination revealed cerebellar ataxia, sensorineural deafness, and bilateral pyramidal tract injury. Susceptibility-weighted magnetic resonance imaging showed linear hypointense signals on the surface of the cerebral hemispheres, sulcus gyrus, lateral ventricles, and cerebellum. The patient underwent treatment with deferiprone, mecobalamin, and vitamin B1, and the symptoms were not aggravated. The patient's daily living ability was near normal after 1 year of follow-up. A literature review indicated that most SSCNS patients present diverse clinical manifestations. Clinicians may consider SSCNS in patients with hearing impairment and gait ataxia, especially for those receiving anticoagulant therapy and with a history of brain injury or accident.

Evaluation of iron deposition in the motor CSTC loop of a Chinese family with paroxysmal kinesigenic dyskinesia using quantitative susceptibility mapping

Introduction

Previous studies have revealed structural, functional, and metabolic changes in brain regions inside the cortico-striatal-thalamo-cortical (CSTC) loop in patients with paroxysmal kinesigenic dyskinesia (PKD), whereas no quantitative susceptibility mapping (QSM)-related studies have explored brain iron deposition in these areas.

Methods

A total of eight familial PKD patients and 10 of their healthy family members (normal controls) were recruited and underwent QSM on a 3T magnetic resonance imaging system. Magnetic susceptibility maps were reconstructed using a multi-scale dipole inversion algorithm. Thereafter, we specifically analyzed changes in local mean susceptibility values in cortical regions and subcortical nuclei inside the motor CSTC loop.

Results

Compared with normal controls, PKD patients had altered brain iron levels. In the cortical gray matter area involved with the motor CSTC loop, susceptibility values were generally elevated, especially in the bilateral M1 and PMv regions. In the subcortical nuclei regions involved with the motor CSTC loop, susceptibility values were generally lower, especially in the bilateral substantia nigra regions.

Conclusion

Our results provide new evidence for the neuropathogenesis of PKD and suggest that an imbalance in brain iron levels may play a role in PKD.

Iron accumulation in the ventral tegmental area in Parkinson's disease

Introduction

The ventral tegmental area (VTA) is less affected compared to substantia nigra pars compacta (SNc) in Parkinson's disease (PD). This study aimed to quantitatively evaluate iron content in the VTA across different stages of PD in order to help explain the selective loss of dopamine neurons in PD.

Methods

Quantitative susceptibility mapping (QSM) data were obtained from 101 PD patients, 35 idiopathic rapid eye movement sleep behavior disorder (RBD) patients, and 62 healthy controls (HCs). The mean QSM values in the VTA and SNc were calculated and compared among the groups.

Results

Both RBD and PD patients had increased iron values in the bilateral SNc compared with HCs. RBD and PD patients in the Hoehn-Yahr (H & Y) stage 1 did not show elevated iron values in the VTA, while PD patients with more than 1.5 H & Y staging had increased iron values in bilateral VTA compared to HCs.

Discussion

This study shows that there is no increased iron accumulation in the VTA during the prodromal and early clinical stages of PD, but iron deposition increases significantly as the disease becomes more severe.

Magnetic resonance evidence of increased iron content in subcortical brain regions in asymptomatic Alzheimer's disease

While iron over-accumulation has been reported in late stage Alzheimer's disease (AD), whether this occurs early in the asymptomatic stage of AD remains unknown. We aimed to assess brain iron levels in asymptomatic AD using quantitative MR relaxometry of effective transverse relaxation rate (R2*) and longitudinal relaxation rate (R1), and recruited 118 participants comprised of three groups including healthy young participants, and cognitively normal older individuals without or with positive AD biomarkers based on cerebrospinal fluid (CSF) proteomics analysis. Compared with the healthy young group, increased R2* was found in widespread cortical and subcortical regions in the older groups. Further, significantly higher levels of R2* were found in the cognitively normal older subjects with positive CSF AD biomarker (i.e., asymptomatic AD) compared with those with negative AD biomarker in subcortical regions including the left and right caudate, left and right putamen, and left and right globus pallidus (p < .05 for all regions), suggesting increased iron content in these regions. Subcortical R2* of some regions was found to significantly correlate with CSF AD biomarkers and neuropsychological assessments of visuospatial functions. In conclusion, R2* could be a valuable biomarker for studying early pathophysiological changes in AD.

Distribution pattern of iron deposition in the basal ganglia of different motor subtypes of Parkinson's disease

OBJECTIVE

The quantitative susceptibility mapping (QSM) technique was used to analyze the distribution pattern of iron deposition in the basal ganglia region of patients with motor subtypes of Parkinson's disease (PD) and to explore the difference in iron content in the basal ganglia region of PD motor subtypes on the major motor symptomatic side.

METHODS

The study included 76 patients with PD and 37 healthy controls (HC). Patients with PD were divided into two groups: postural instability/gait disorder (PIGD)(n = 48), and tremor dominance (TD)(n = 28). We classified patients with PD according to the side of the major motor symptoms as left PIGD (n = 23), left TD (n = 14), right PIGD (n = 25), and right TD (n = 14). All subjects underwent brain magnetic resonance scanning to obtain QSM and susceptibility values in the corresponding regions of interest (ROI).

RESULTS

(1) Compared with the HC, the bilateral SN in the PD-PIGD and TD group showed greater susceptibility values. The susceptibility values in the left CN, bilateral PUT were also greater in the PD-PIGD group than the HC. (2) Compared with the TD, the left PUT susceptibility values were greater in the PIGD group, especially in patients whose major symptomatic side were on the right limb. (3) Correlation analysis showed that in the PD group, bilateral SN was positively correlated with the unified Parkinson's disease rating scale III part scores of the Movement Disorder Society (MDS-UPDRS III) and the Hoehn-Yahr stage. Bilateral dentate nucleus (DN) susceptibility values were significantly positively correlated with TD scores, and left PUT susceptibility values were positively correlated with PIGD scores. The left SN within the PIGD group was positively correlated with the PIGD score.

CONCLUSION

There were different iron deposition patterns in the basal ganglia between the PD-PIGD and TD groups. There also seems to be a difference in iron deposition in PD motor subtypes on different major motor symptom sides.

CSF ferritin in the clinicopathological progression of Alzheimer's disease and associations with APOE and inflammation biomarkers

BACKGROUND

A putative role for iron in driving Alzheimer's disease (AD) progression is complicated by previously reported associations with neuroinflammation, apolipoprotein E and AD proteinopathy. To establish how iron interacts with clinicopathological features of AD and at what disease stage iron influences cognitive outcomes, we investigated the association of cerebrospinal fluid (CSF) biomarkers of iron (ferritin), inflammation (acute phase response proteins) and apolipoproteins with pathological biomarkers (CSF Aβ42/t-tau, p-tau181), clinical staging and longitudinal cognitive deterioration in subjects from the BioFINDER cohort, with replication of key results in the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort.

METHODS

Ferritin, acute phase response proteins (n=9) and apolipoproteins (n=6) were measured in CSF samples from BioFINDER (n=1239; 4 years cognitive follow-up) participants stratified by cognitive status (cognitively unimpaired, mild cognitive impairment, AD) and for the presence of amyloid and tangle pathology using CSF Aβ42/t-tau (A+) and p-tau181 (T+). The ferritin and apolipoprotein E associations were replicated in the ADNI (n=264) cohort.

RESULTS

In both cohorts, ferritin and apoE were elevated in A-T+ and A+T+ subjects (16%-40%), but not clinical diagnosis. Other apolipoproteins and acute phase response proteins increased with clinical diagnosis, not pathology. CSF ferritin was positively associated with p-tau181, which was mediated by apolipoprotein E. An optimised threshold of ferritin predicted cognitive deterioration in mild cognitive impairment subjects in the BioFINDER cohort, especially those people classified as A-T- and A+T-.

CONCLUSIONS

CSF markers of iron and neuroinflammation have distinct associations with disease stages, while iron may be more intimately associated with apolipoprotein E and tau pathology.

Association between susceptibility value and cerebral blood flow in the bilateral putamen in patients undergoing hemodialysis

Hemodialysis (HD) is the most regularly applied replacement therapy for end-stage renal disease, but it may result in brain injuries. The correlation between cerebral blood flow (CBF) alteration and iron deposition has not been investigated in patients undergoing HD. Ferritin level may be a dominant factor in CBF and iron deposition change. We hypothesize that ferritin level might be the key mediator between iron deposition and CBF alteration. The correlation in the putamen was estimated between the susceptibility values and CBF in patients undergoing HD. Compared with healthy controls, patients showed more altered global susceptibility values and CBF. The susceptibility value was negatively correlated with CBF in the putamen in patients. Moreover, the susceptibility value was negatively correlated with ferritin level and positively correlated with serum iron level in the putamen of patients. CBF was positively correlated with ferritin level and negatively correlated with serum iron level in the putamen of patients. These findings indicate that iron dyshomeostasis and vascular damage might exist in the putamen in patients. The results revealed that iron dyshomeostasis and vascular damage in the putamen may be potential neural mechanisms for neurodegenerative processes in patients undergoing HD.

Iron accumulation and axonal damage of cerebellum in idiopathic cervical dystonia

BACKGROUND AND PURPOSE

Postmortem brain study indicated that cerebellar Purkinje cell (PC) loss might be a pathological finding in patients with inherited and idiopathic cervical dystonia (ICD). The analysis of conventional magnetic resonance imaging brain scans failed to yield support for this finding. Previous studies have identified that iron overload can be the consequence of neuron death. The objectives of this study were to investigate iron distribution and demonstrate changes in axons in the cerebellum, providing evidence for PC loss in patients with ICD.

METHODS

Twenty-eight patients with ICD (20 females) and 28 age- and sex-matched healthy controls were recruited. A spatially unbiased infratentorial template was applied to perform cerebellum optimized quantitative susceptibility mapping and diffusion tensor analysis based on magnetic resonance imaging. Voxel-wise analysis was performed to assess cerebellar tissue magnetic susceptibility and fractional anisotropy (FA) alterations, and the clinical relevance of these findings was investigated in the patients with ICD.

RESULTS

Increased susceptibility values revealed by quantitative susceptibility mapping in the right lobule CrusI, CrusII, VIIb, VIIIa, VIIIb and IX were found in the patients with ICD. A reduced FA value was found across almost all the cerebellum; an FA value of the significant clusters within the right lobule VIIIa significantly correlated with the motor severity of patients with ICD (r = -0.575, p = 0.002).

CONCLUSIONS

Our study provided evidence for cerebellar iron overload and axonal damage in patients with ICD, which may indicate PC loss and related axonal changes. These results provide evidence for the neuropathological findings in patients with ICD and further highlight the cerebellar involvement in the pathophysiology of dystonia.

Thalamic subfield iron accumulation after acute mild traumatic brain injury as a marker of future post-traumatic headache intensity

OBJECTIVE

To explore alterations in thalamic subfield volume and iron accumulation in individuals with post-traumatic headache (PTH) relative to healthy controls.

BACKGROUND

The thalamus plays a pivotal role in the pathomechanism of pain and headache, yet the role of the thalamus in PTH attributed to mild traumatic brain injury (mTBI) remains unclear.

METHODS

A total of 107 participants underwent multimodal T1-weighted and T2* brain magnetic resonance imaging. Using a clinic-based observational study, thalamic subfield volume and thalamic iron accumulation were explored in 52 individuals with acute PTH (mean age = 41.3; standard deviation [SD] = 13.5), imaged on average 24 days post mTBI, and compared to 55 healthy controls (mean age = 38.3; SD = 11.7) without history of mTBI or migraine. Symptoms of mTBI and headache characteristics were assessed at baseline (0-59 days post mTBI) (n = 52) and 3 months later (n = 46) using the Symptom Evaluation of the Sports Concussion Assessment Tool (SCAT-5) and a detailed headache history questionnaire.

RESULTS

Relative to controls, individuals with acute PTH had significantly less volume in the lateral geniculate nucleus (LGN) (mean volume: PTH = 254.1, SD = 43.4 vs. controls = 278.2, SD = 39.8; p = 0.003) as well as more iron deposition in the left LGN (PTH: T2* signal = 38.6, SD = 6.5 vs. controls: T2* signal = 45.3, SD = 2.3; p = 0.048). Correlations in individuals with PTH revealed a positive relationship between left LGN T2* iron deposition and SCAT-5 symptom severity score at baseline (r = -0.29, p = 0.019) and maximum headache intensity at the 3-month follow-up (r = -0.47, p = 0.002).

CONCLUSION

Relative to healthy controls, individuals with acute PTH had less volume and higher iron deposition in the left LGN. Higher iron deposition in the left LGN might reflect mTBI severity and poor headache recovery.

White Matter Tract Injury by MRI in CADASIL Patients is Associated With Iron Accumulation

BACKGROUND

Widespread white matter (WM) injury is a hallmark feature of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, controversies about the mechanism of WM tract injury exist persistently. Excessive iron accumulation, frequently reported in CADASIL patients, might cause WM tract injury.

PURPOSE

To test the association between iron accumulation and WM tract injury in CADASIL patients.

STUDY TYPE

Retrospective.

POPULATION

A total of 35 CADASIL patients (age = 50.4 ± 6.4, 62.9% female) and 48 healthy controls (age = 55.7 ± 8.0, 68.8% female).

FIELD STRENGTH/SEQUENCE

Diffusion-weighted spin-echo echo-planar sequence; enhanced susceptibility-weighted angiography (ESWAN) gradient echo sequence on a 3 T scanner.

ASSESSMENT

The phase images acquired by ESWAN were used to calculate quantitative susceptibility mapping (QSM). Iron accumulation was evaluated in deep gray matters using QSM. WM tract injury was quantified by diffusion metrics based on WM major tracts skeleton. We compared iron deposition between groups and analyzed the correlation between WM tract injury and iron deposition in regions showing significant differences from healthy controls. Exploratory analysis was carried out to investigate whether WM tract injury mediated the relationship between iron deposition and cognitive impairment evaluated by Mini-Mental State Examination (MMSE).

STATISTICAL TESTS

General linear model (GLM), partial correlation, stepwise linear regression and mediation analysis were used. The threshold of statistical significance was set as p < 0.05.

RESULTS

Compared with healthy controls, CADASIL patients had significantly increased iron deposition in the caudate and putamen. Aberrant iron deposition in these two regions was significantly associated with decreased WM fractional anisotropy (FA) (caudate, r = -0.373； putamen, r = - 0.421), and increased radial diffusivity (RD) (caudate, r = 0.372; putamen, r = 0.386). Furthermore, WM tract injury mediated the relationship between iron deposition and cognitive impairment.

DATA CONCLUSION

Patients with CADASIL show increased iron deposition in the caudate and putamen that is correlated to WM tract injury, which may in turn mediate the association with cognitive impairment.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Magnetic resonance spectroscopy for quantification of liver iron deposition in hereditary hemochromatosis of a Chinese family: Four case reports

RATIONALE

Hereditary hemochromatosis (HH) is a major cause of liver iron overload. The gold standard for the diagnosis of liver iron overload is the histopathological analysis of a liver sample collected by biopsy. The biopsy procedure is both invasive and painful and carries some risks of complications. The multi-echo single-voxel magnetic resonance spectroscopy (HISTO) technique can be used for noninvasive, quantitative assessment of liver iron overload.

PATIENT CONCERNS

We report 4 Chinese Han men, who were relatives. Patient A was admitted with diabetes and presented with thrombocytopenia and skin hyperpigmentation. The other patients had no specific clinical presentation.

DIAGNOSES

Patient A was suspected of having iron in the liver on routine magnetic resonance imaging, therefore, further HISTO, laboratory testing, and liver biopsy were performed, which confirmed iron metabolic abnormalities. Furthermore, we identified hepatic iron deposition using HISTO and laboratory testing of his son and 2 brothers. Combined with symptoms, auxiliary examinations, and liver biopsy, HH was considered.

INTERVENTIONS

As the 4 patients had no other discomfort other than patient A who had diabetes, patient A was placed on therapy comprising the insulin pump, acarbose, and platelet booster capsule.

OUTCOMES

After treatment, the diabetic symptoms of patient A improved. The patient and his relatives were regularly followed-up for HH.

LESSONS

HH should be considered when hepatic iron deposition is suspected by routine magnetic resonance, as the HISTO sequence can quantitate liver iron deposition and leads to a promising diagnosis. HISTO is of great value in familial cases, especially in young patients requiring long-term follow-up.

Effect of Iron Deposition on Native T1 Mapping and Blood Oxygen Level Dependent for the Assessment of Liver Fibrosis in Rabbits With Carbon Tetrachloride Intoxication

RATIONALE AND OBJECTIVES

This study aimed to explore the effect of iron deposition on native T1 mapping and blood oxygen level-dependent (BOLD) imaging in detecting liver fibrosis (LF) in a rabbit model.

MATERIALS AND METHODS

An LF group (n = 100) was established by subcutaneously injecting 50% carbon tetrachloride (CCl₄) oil solution, and 20 normal rabbits composed a control group. Native T1 mapping and BOLD were performed, and the T1_native and R₂* quantitative parameters were analyzed by receiver operating characteristic (ROC) and multiple logistic regression analyses, with histopathological results and liver iron content (LIC) serving as reference standards.

RESULTS

In total, 18, 17, 16, 18, and 15 rabbits were histopathologically diagnosed with LF stages F0, F1, F2, F3, and F4, respectively. T1_native (r = 0.47), R₂* (r = 0.75) and LIC (r = 0.61) increased with LF stage progression (p < 0.001). Compared to T1_native values, R₂* performed better in diagnosing the LF stage, especially for distinguishing F1-F2 from F3-F4 (AUC = 0.66 vs. 0.91, p = 0.01). Combined with the LIC, both T1_native and R₂* showed improved diagnostic value in comparison to the individual imaging techniques, particularly for diagnosing F0 vs. F1-F2 and F0 vs. F1-F4, with AUC values of 0.90 vs. 0.70 (p = 0.01) and 0.93 vs. 0.77 (p = 0.01) for T1_native + LIC vs. LIC, respectively.

CONCLUSION

BOLD imaging performed better than native T1 mapping in predicting and diagnosing LF stage progression. The decrease in diagnostic accuracy caused by the deposition of liver iron is a potential pitfall in the assessment of LF with BOLD imaging and native T1 mapping.

Alterations in brain iron deposition with progression of late-life depression measured by magnetic resonance imaging (MRI)-based quantitative susceptibility mapping

BACKGROUND

Previous studies have revealed abnormality of iron deposition in the brain of patients with depression. The progression of iron deposition associated with depression remains to be elucidated.

METHODS

This is a longitudinal study. We explored brain iron deposition with disease progression in 20 patients older than 55 years with depression and on antidepressants, using magnetic resonance imaging (MRI)-based quantitative susceptibility mapping (QSM). Magnetic susceptibility values of the whole brain were compared between baseline and approximately one-year follow-up scans using permutation testing. Furthermore, we examined the relationship of changes between the susceptibility values and disease improvement using Spearman's partial correlation analysis, controlling for age, gender, and the visit interval.

RESULTS

Compared to the initial scan, increased magnetic susceptibility values were found in the medial prefrontal cortex (mPFC), dorsal anterior cingulate cortex (dACC), occipital areas, habenula, brainstem, and cerebellum (P<0.05, corrected). The susceptibility values decreased in the dorsal part of the mPFC, middle and posterior cingulate cortex (MCC and PCC), right postcentral gyrus, right inferior parietal lobule, right precuneus, right supramarginal gyrus, left lingual gyrus, left dorsal striatum, and right thalamus (P<0.05, corrected). Notably, the increase in susceptibility values at the mPFC and dACC negatively correlated with the changes in depression scores, as calculated using the Hamilton Depression Scale (HAMD) (r=-0.613, P=0.009), and the increase in susceptibility values at the cerebellum and habenula negatively correlated with the changes in cognitive scores, which were calculated using the Mini-Mental State Examination (MMSE) (cerebellum: r=-0.500, P=0.041; habenula: r=-0.588, P=0.013). Additionally, the decreased susceptibility values at the white matter near the mPFC (anterior corona radiata) also correlated with the changes in depression scores (r=-0.541, P=0.025), and the decreased susceptibility values at the left lingual gyrus correlated with the changes in cognitive scores (r=-0.613, P=0.009).

CONCLUSIONS

Our study identified brain areas where iron deposition changed with the progression of depression while on antidepressants. The linear relationship of changes in the magnetic susceptibility values in the mPFC, dACC, and some subcortical areas with changes in depression symptoms and cognitive functions of patients is highlighted. Our results strengthen the understanding of the alterations of brain iron levels associated with disease progression in patients with late-life depression.

The increased iron deposition of the gray matter over the whole brain in chronic migraine: an exploratory quantitative susceptibility mapping study

Background

Prior studies identified iron deposition in deep brain nuclei and the periaqueductal gray matter region in chronic migraine, and less is known about the cerebral iron deposition over the whole cerebral gray matter in CM. The aim of this case–control study is to investigate the cerebral iron deposition of gray matter in CM using an advanced quantitative susceptibility mapping.

Methods

A multi-echo gradient echo MR sequence was used to obtain raw quantitative susceptibility mapping data from 12 CM patients and 18 normal controls and the quantitative susceptibility mapping were reconstructed. Three dimensional T1 images were segmented and the gray matter mask was generated to extract the susceptibility value of gray matter over the whole brain. The independent t test and receiver operating characteristic curve Receiver operating characteristics was used to investigate the iron deposition changes in CM patients.

Results

CM presented a higher susceptibility value (1.44 × 10⁻³ ppm) compared with NC group (0.47 × 10⁻³ ppm) (p < 0.0001) over the whole cerebral gray matter. There was no correlation between susceptibility value and the clinical variables including disease duration, Visual Analog Scale (VAS), Migraine Disability Assessment Scale (MIDAS), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), and Montreal Cognitive Assessment (MoCA) scores (p > 0.05). ROC analysis demonstrated the susceptibility had a high diagnostic efficacy (AUC 0.949, sensitivity 77.78% and specificity 100%) in distinguishing CM from NC.

Conclusion

CM patients had increased iron deposition in total cerebral gray matter which could be considered as a potential diagnostic and evaluated imaging biomarker in CM.

Iron Deposition in Gray Matter Nuclei of Patients With Intracranial Artery Stenosis: A Quantitative Susceptibility Mapping Study

Purpose: This study aimed to use quantitative susceptibility mapping (QSM) to systematically investigate the changes of iron content in gray matter (GM) nuclei in patients with long-term anterior circulation artery stenosis (ACAS) and posterior circulation artery stenosis (PCAS).

Methods: Twenty-five ACAS patients, 25 PCAS patients, and 25 age- and sex-matched healthy controls underwent QSM examination. Patients were scored using the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) to assess the degree of neural function deficiency. On QSM images, iron related susceptibility of GM nuclei, including bilateral caudate nucleus, putamen (PU), globus pallidus (GP), thalamus (TH), substantia nigra (SN), red nucleus, and dentate nucleus (DN), were assessed. Susceptibility was compared between bilateral GM nuclei in healthy controls, ACAS patients, and PCAS patients. Partial correlation analysis, with age as a covariate, was separately performed to assess the relationships of susceptibility with NIHSS and mRS scores.

Results: There were no significant differences between the susceptibilities for left and right hemispheres in all seven GM nucleus subregions for healthy controls, ACAS patients, and PCAS patients. Compared with healthy controls, mean susceptibility of bilateral PU, GP, and SN in ACAS patients and of bilateral PU, GP, SN, and DN in PCAS patients were significantly increased (all P < 0.05). In addition, mean susceptibility of bilateral TH and SN in PCAS patients was significantly higher than in ACAS patients (both P < 0.05). With partial correlation analysis, mean susceptibility at bilateral PU of ACAS patients was significantly correlated with mRS score (r = 0.415, P < 0.05), and at bilateral PU in PCAS patients was correlated with NIHSS score (r = 0.424, P < 0.05).

Conclusion: Our findings indicated that abnormal iron metabolism may present in different subregions of GM nuclei after long-term ACAS and PCAS. In addition, iron content of PU in patients with ACAS and PCAS was correlated with neurological deficit scores. Therefore, iron quantification measured by QSM susceptibility may provide a new insight to understand the pathological mechanism of ischemic stroke caused by ACAS and PCAS.

Quantitative susceptibility mapping to evaluate brain iron deposition and its correlation with physiological parameters in hypertensive patients

Background

Regional excessive iron overload is pernicious to motor functions and cognitive functioning of the brain. The aim of this research was to utilize quantitative susceptibility mapping (QSM) to inspect brain iron accumulation in patients with hypertension (HP), and to evaluate whether it is correlated with physiological parameters.

Methods

Thirty-one HP and 31 age- and sex-matched healthy controls (HC) were included. All participants underwent brain magnetic resonance imaging (MRI), and QSM data were obtained. Differences in brain iron deposition in deep gray matter nuclei of participants were compared between HP and HC. The correlations between iron deposition, body mass index (BMI), maximum systolic blood pressure (SBP), and diastolic blood pressure (DBP) were analyzed.

Results

The HP group showed increased susceptibility values in the caudate nucleus (CA), putamen (PU), globus pallidus (GP), and dorsal thalamus (TH), compared with the HC group. There was a significant positive correlation between BMI and the susceptibility values in the dentate nucleus (DN); the maximum SBP and DBP were positively correlated with magnetic susceptibility of the CA, PU, GP, and TH, respectively.

Conclusions

These results are indicative of the role of overload brain iron in deep brain gray matter nuclei in HP and suggest that HP is associated with excess brain iron in certain deep gray matter regions.

New imaging features of tuberous sclerosis complex: A 7 T MRI study

Few in vivo studies have focused on the perivenous association of tubers and iron deposition in the deep gray nuclei in patients with tuberous sclerosis complex (TSC). We investigated this possible relationship in TSC patients using susceptibility weighted imaging (SWI) at 7 T. SWI with high spatial resolution and enhanced sensitivity was performed on 11 TSC patients in comparison with 15 age- and sex-matched healthy controls. The relationship between tubers and veins was evaluated. In addition, the phase images of SWI were processed to produce local field shift (LFS) maps to quantify iron deposition. The mean LFS in the deep gray nuclei was compared between the TSC patients and healthy controls using a covariance analysis. Venous involvement was observed in 211 of the 231 (91.3%) cortical tubers on SWI. The slender tubers often oriented around the long axis of penetrating veins, possibly because cortical tubers typically developed and/or migrated along venous vasculatures. A significant difference in LFS of the thalamus was detected between the TSC patients and healthy controls (3.36 ± 0.50 versus 3.01 ± 0.39, p < 0.01). The new in vivo imaging features observed at 7 T provide valuable insights into the possible venous association of TSC lesions and iron accumulation in the deep gray nuclei. Our results may lead to a better understanding of the pathological changes involved in TSC under in vivo conditions.

Time-Specific Pattern of Iron Deposition in Different Regions in Parkinson's Disease Measured by Quantitative Susceptibility Mapping

Studies have shown the spatial specificity of cranial iron deposition in different regions in Parkinson's disease (PD). However, the time-specific patterns of iron deposition are not yet clear. The purpose of this study was to investigate the time pattern of iron variations and its clinical relevance in multiple gray matter nuclei in PD using quantitative susceptibility mapping (QSM). Thirty controls and 33 PD patients were enrolled, namely, 11 cases of early stage of PD (ESP) and 22 cases of advanced stage of PD (ASP) according to the Hoehn-Yahr stages. The iron content in the subcortical nuclei covering substantia nigra (SN), red nucleus (RN), head of the caudate nucleus (CN), globus pallidus (GP), and putamen (PT) was measured using QSM, and the clinical symptoms of PD were evaluated by various rating scales. The QSM values in SN, RN, GP, and PT significantly increased in PD patients compared with the controls. Further subgroup comparison with the controls indicated that the iron content in SN and GP (paleostriatum) gradually elevated in the whole disease duration and was related to clinical features. While the iron content in RN and PT (neostriatum) only elevated significantly in ESP patients, further iron deposition was not obvious in ASP patients. Our study confirmed that QSM could be used as a disease biomarker and could be suitable for longitudinal monitoring. However, considering the temporal characteristics of iron deposition in neostriatum, iron deposition in the neostriatum should be paid more attention in the early stage of the disease, even in the preclinical stage, in future research.

Erastin‑induced ferroptosis causes physiological and pathological changes in healthy tissues of mice

Ferroptosis is a non-apoptotic form of cell death that relies on iron and lipid peroxidation, which is associated with multiple pathological processes in several diseases. Erastin is a small molecule capable of initiating ferroptotic cell death in cancer cells, which has shown great potential for cancer therapy. However, the physiological and pathological role of erastin-induced ferroptosis on healthy tissues has not been well characterized. The present study intraperitoneally injected erastin into healthy mice to detect the metabolic changes of several tissues of mice. Erastin injection induced typical characteristics of ferroptosis with higher level of serum iron and malondialdehyde and lower level of glutathione and glutathione peroxidase 4 protein. Erastin injection enhanced iron deposition in the brain, duodenum, kidney and spleen of mice. Erastin-induced ferroptosis altered the blood index values, causing mild cerebral infarction of brain and enlarged glomerular volume of kidney. It also promoted the growth of duodenal epithelium with thicker, longer and denser villi in erastin-treated mice. The findings provided evidence that erastin induced ferroptosis and caused pathological changes in healthy tissues of mice. This suggested that the anti-tumor drug erastin was somewhat toxic to healthy tissues.

Voxel-based quantitative susceptibility mapping revealed increased cerebral iron over the whole brain in chronic migraine

Background

The previous documents demonstrated that iron deposition was identified in brain deep nuclei and periaqueductal gray matter region in chronic migraine (CM), and less is known about the cerebral iron deposition in CM. The aim of this study is to investigate the cerebral iron deposition in CM using an advanced voxel-based quantitative susceptibility mapping.

Methods

A multi-echo gradient echo MR sequence was obtained from 14 CM patients and 28 normal controls (NC), and quantitative susceptibility mapping images were reconstructed and voxel-based analysis was performed over the whole cerebrum. The susceptibility value of all the positive brain regions was extracted and correlation was calculated between the susceptibility value and the clinical variables.

Results

The brain regions with increased susceptibility value in CM patients located in right precuneus, insula, supramarginal gyrus, dorsolateral superior frontal gyrus, postcentral gyrus, cuneus and left postcentral gyrus compared with NC. The correlation analysis demonstrated that a positive correlation was identified between susceptibility value of all the positive brain regions and VAS score.

Conclusion

The current study demonstrated increased cerebral iron deposition presented in chronic patients, which suggested that increased cerebral iron deposition might play a role in the migraine chronicization.

Iron Deposition Characteristics of Deep Gray Matter in Elderly Individuals in the Community Revealed by Quantitative Susceptibility Mapping and Multiple Factor Analysis

Purpose

The objective of this study was to determine which factors influence brain iron concentrations in deep gray matter in elderly individuals and how these factors influence regional brain iron concentrations.

Methods

A total of 105 elderly individuals were enrolled in this study. All participants underwent detailed magnetic resonance imaging (MRI) examinations from October 2018 to August 2019. Among them, 44 individuals had undergone a previous MRI examination from July 2010 to August 2011. Quantitative susceptibility mapping (QSM) was utilized as an indirect quantitative marker of brain iron, and the susceptibility values of deep gray matter structures were obtained. Univariate analysis and multiple linear regression analysis were used to investigate 11 possible determinants for cerebral iron deposition.

Results

Our results showed no sex- or hemisphere-related differences in susceptibility values in any of the regions studied. Aging was significantly correlated with increased insusceptibility values in almost all analyzed brain regions (except for the thalamus) when we compared the susceptibility values at the two time points. In a cross-sectional analysis, the relationship between gray matter nucleus susceptibility values and age was conducted using Pearson’s linear regression. Aging was significantly correlated with the susceptibility values of the globus pallidus (GP), putamen (Put), and caudate nucleus (CN), with the Put having the strongest correlations. In multiple linear regression models, associations with increased susceptibility values were found in the CN, Put, red nucleus, and dentate nucleus for individuals with a history of type 2 diabetes mellitus (T2DM). However, the patients with hypertension showed significantly reduced susceptibility values in the red nucleus and dentate nucleus. Our data suggested that smokers had increased susceptibility values in the thalamus. No significant associations were found for individuals with a history of hypercholesterolemia and Apolipoprotein E4 carrier status.

Conclusion

Our data revealed that aging, T2DM, and smoking could increase iron deposition in some deep gray matter structures. However, hypertension had the opposite effects in the red nuclei and dentate nuclei. Brain iron metabolism could be influenced by many factors in different modes. In future studies, we should strictly control for confounding factors.

Iron Protein Succinylate in the Management of Iron Deficiency Anemia: A Comparative Study with Ferrous Sulphate at Low and High Therapeutic Doses

Oral iron supplementation constitutes the first line treatment for iron deficiency anemia (IDA), with daily doses between 80 mg and 200 mg of elemental iron. Ferrous salts, such as ferrous sulphate (FeSO4), while efficacious, frequently give rise to gastrointestinal side effects. In the present paper we attempted to directly compare the efficacy of an alternative to the FeSO4 formulation, which presents a better tolerability profile, iron protein succinylate (Ferplex®). In a diet-induced anemia model, rats were treated by oral gavage with vehicle, FeSO4, or Ferplex® at a human-dose equivalent of 80 mg and 200 mg of elemental iron. We evaluated the change in anemia-related hematological and biochemical parameters, conducting a histological examination of the intestine at sacrifice. Results indicate that both types of iron supplementation are equally effective in the treatment of IDA, restoring hemoglobin, hematocrit, erythrocytes, free iron and transferrin levels in 15 days, with no statistical differences between treated groups and control. The impact of anemia on body weight was also attenuated following treatment with both iron supplements. Thrombocyte and reticulocyte levels, altered by the anemic condition, returned to homeostasis after 15 days of either FeSO4 or Ferplex® treatment. Importantly, the lower and higher doses of iron were equally effective, thus supporting the current school of thought which states that lower therapeutic doses are sufficient for management of IDA. In addition, the study shows for the first time that oral treatment with Ferplex® does not increase serum hepcidin. Finally, Ferplex® induced minimal iron depositions in the intestinal tissue compared to FeSO4.

Susceptibility-weighted Imaging for Renal Iron Overload Assessment: A Pilot Study

Purpose: To explore the feasibility of susceptibility-weighted imaging (SWI) for evaluating renal iron overload.

Methods: Twenty-eight rabbits were randomly assigned into control (n = 14) and iron (n = 14) group. In the 0th week, the study group was injected with iron dextran. Both groups underwent SWI examination at the 0th, 8th, and 12th week. The signal intensity (SI) of cortex and medulla was assessed. Angle radian value (ARV) calculated with phase image was taken as the quantitative value for cortical and medullary iron deposition. After the 12th week, the left kidneys of rabbits were removed for pathology. The difference in the ARV among three groups was analyzed using Kruskal–Wallis test. The difference of the iron content between two groups was analyzed through independent sample t-test.

Results: In the iron group: at the 12th week, eight rabbits were found to have decreased SI of only cortex, and the other six rabbits had decreased SI of cortex and medulla by the same degree; the ARV of cortex at the 8th and 12th week was significantly higher than that of the 0th week (P < 0.05); the ARV of the six rabbits’ medulla at the 12th week was significantly higher than that of the 0th week, 8th week, and the other eight rabbits at the 12th week (P < 0.05); at the 12th week, eight rabbits (iron group) were found to have many irons only deposit in the cortex, and the others were found to have many irons deposit in both cortex and medulla; the iron content of cortex and six rabbits’ medulla in the iron group was significantly higher than that of the control (P < 0.05).

Conclusion: The ARV of SWI can be used to quantitatively assess the excess iron deposition in the kidneys. Excessive iron deposition mainly occurs in the cortex or medulla and causes their SWI SI to decrease.

Increased Brain Iron Detection by Voxel-Based Quantitative Susceptibility Mapping in Type 2 Diabetes Mellitus Patients With an Executive Function Decline

Purpose

Brain iron accumulation has been suggested as a pathomechanism in patients with type 2 diabetes mellitus (T2DM) with cognitive impairment. This research aims to examine the total-brain pattern of iron accumulation in relation to executive function decline in patients with T2DM by voxel-based quantitative susceptibility mapping (QSM) analysis.

Materials and Methods

A total of 32 patients with T2DM and 34 age- and sex-matched healthy controls (HCs) were enrolled in this study. All participants underwent brain magnetic resonance examination, and 48 individuals underwent cognitive function assessments. Imaging data were collected with three-dimensional fast low-angle shot sequences to achieve magnitude as well as phase images. Using voxel-based QSM analysis, we compared the voxel-wise susceptibility values of the whole brain among groups and explored whether the susceptibility values had correlations with cognitive data.

Results

Among the 66 participants, cognitive function was estimated in 23 patients with T2DM (11 males and 12 females; average age, 64.65 ± 8.44 years) and 25 HCs (13 males and 12 females; average age, 61.20 ± 7.62 years). T2DM patients exhibited significantly (t = 4.288, P < 0.001) lower Montreal Cognitive Assessment (MoCA) scores [T2DM, 27 (27, 28); HCs, 29 (28, 29); normal standard ≥ 26)] and higher Trail-making Test (TMT)-A/TMT-B scores [71 (51, 100)/185 (149, 260)] than HCs [53 (36.5, 63.5)/150 (103, 172.5)] (Z = 2.612, P = 0.009; Z = 2.797, P = 0.005). Subjects with T2DM showed significantly higher susceptibility values than HCs in the caudate/putamen/pallidum, frontal inferior triangular gyrus, and precentral gyrus on the right hemisphere. In contrast (HC > T2DM), no region showed a significant difference in susceptibility values between the groups. The correlation analysis between susceptibility values and cognitive function scores was tested by voxel-based susceptibility value with sex and age as covariates. After multiple comparison correction, in T2DM patients, the left thalamus showed a significant relationship with TMT-A (R ² = 0.53, P = 0.001). The right thalamus and left thalamus showed a significant relationship with TMT-B (R ² = 0.35, P = 0.019; and R ² = 0.38, P = 0.017, respectively). In HCs, the cluster of right precentral/middle frontal gyrus/inferior frontal gyrus/inferior triangular gyrus showed a significant relationship with TMT-B (R ² = 0.59, P = 0.010). No relationship was found between the susceptibility values with MoCA in the brain region in both two groups.

Conclusion

Patients with T2DM presented declined cognitive assessments and elevated iron deposition in the striatum and frontal lobe, suggesting that executive function decline in T2DM might be associated with the cerebral iron burden and that changes in susceptibility values may represent a latent quantitative imaging marker for early assessment of cognitive decline in patients with T2DM.

Dysfunction of the Glymphatic System Might Be Related to Iron Deposition in the Normal Aging Brain

Objective: The study aims to detect the potential relationship between iron deposition and the function of the glymphatic system in the normal aging brain.

Methods: We recruited 213 healthy participants. We evaluated the function of the glymphatic system using the index for diffusivity along the perivascular space (ALPS-index), assessed iron deposition on quantitative susceptibility mapping (QSM), and analyzed their relationship.

Results: The mean age of participants was 60.1 ± 7.3, and 107 (50.2%) were female. The mean ALPS-index was 1.4 ± 0.2. The QSM values of the caudate nucleus, putamen, globus pallidus, thalamus, red nucleus, substantia nigra, and dentate nucleus were all related to the ALPS-index (all P < 0.001).

Conclusions: The main finding of the current study is that the regional brain iron deposition was related to the function of the glymphatic system.

Advances in knowledge: We first evaluated the relationship between deposition of brain iron and the dysfunction of the glymphatic system.

Cortical aging - new insights with multiparametric quantitative MRI

Understanding the microstructural changes related to physiological aging of the cerebral cortex is pivotal to differentiate healthy aging from neurodegenerative processes. The aim of this study was to investigate the age-related global changes of cortical microstructure and regional patterns using multiparametric quantitative MRI (qMRI) in healthy subjects with a wide age range. 40 healthy participants (age range: 2^nd to 8^th decade) underwent high-resolution qMRI including T1, PD as well as T2, T2* and T2′ mapping at 3 Tesla. Cortical reconstruction was performed with the FreeSurfer toolbox, followed by tests for correlations between qMRI parameters and age. Cortical T1 values were negatively correlated with age (p=0.007) and there was a widespread age-related decrease of cortical T1 involving the frontal and the parietotemporal cortex, while T2 was correlated positively with age, both in frontoparietal areas and globally (p=0.004). Cortical T2′ values showed the most widespread associations across the cortex and strongest correlation with age (r= -0.724, p=0.0001). PD and T2* did not correlate with age. Multiparametric qMRI allows to characterize cortical aging, unveiling parameter-specific patterns. Quantitative T2′ mapping seems to be a promising imaging biomarker of cortical age-related changes, suggesting that global cortical iron deposition is a prominent process in healthy aging.

Targeting hepcidin improves cognitive impairment and reduces iron deposition in a diabetic rat model

Cognitive impairment is a common complication of type 2 diabetes mellitus (T2DM) that may be related to iron deposition in the brain. Hepcidin is expressed in the brain and has the ability to regulate iron. Therefore, this study explored the role of hepcidin in hippocampal iron deposition and cognitive impairment in T2DM. The effects of a recombinant adeno-associated virus targeting hepcidin (AAV-hepcidin) for hippocampal iron content and cognitive function were investigated in a T2DM rat model induced by streptozotocin and a high-fat diet. Adult male rats (n = 32) were categorized as either C-saline (normal control), M-saline (T2DM), M-blank (AAV-blank + T2DM), or M-hepcidin (AAV-hepcidin + T2DM). Hippocampal iron content was assessed using quantitative susceptibility mapping. Morris water maze (MWM) testing was used to assess the cognitive function. Magnetic resonance imaging indicated that hippocampal susceptibility values were significantly increased bilaterally in T2DM rats compared with controls (P = 0.044, P = 0.043). Compared with the M-blank group, the M-hepcidin group exhibited significantly decreased hippocampal susceptibility values bilaterally (P = 0.007, P = 0.030). Compared with the M-saline group, susceptibility values from left hippocampus in the M-hepcidin group were significantly reduced (P = 0.002). MWM results showed that the performance of T2DM rats was significantly decreased from that of control rats. Compared with the M-saline and M-blank groups, the performance of the M-hepcidin group was significantly increased. These studies demonstrate that T2DM rats developed cognitive impairment and iron deposits in the hippocampus, both of which were improved by AAV-hepcidin administration.

Late-Onset Carnitine-Acylcarnitine Translocase Deficiency With SLC25A20 c.199-10T>G Variation: Case Report and Pathologic Analysis of Liver Biopsy

Introduction: Carnitine-acylcarnitine translocase deficiency (CACTD) is a rare and life-threatening autosomal recessive disorder of mitochondrial fatty acid oxidation caused by variation of the Solute carrier family 25 member 20 (SLC25A20) gene. Carnitine-acylcarnitine translocase is one of the crucial transport proteins in the oxidation process of mitochondrial fatty acids. In Asia, the c.199-10T>G splice site variation is the most frequently reported variant of SLC25A20. Patients with CACTD with c.199-10T>G variation usually present with a severe clinical phenotype. Materials and Methods: Herein, we report a neonatal case of late-onset CACTD in mainland China. Symptoms emerged 61 days after birth; the patient presented with a severe metabolic crisis, and her clinical condition rapidly deteriorated, and she died of respiratory insufficiency and cardiac arrest at 61 days. We present the clinical and biochemical features of this patient and briefly review previously reported CACTD cases with c.199-10T>G variation. Results: Acylcarnitine profiling by tandem mass spectrometry and high-throughput sequencing revealed that our patient was homozygous for the c.199-10T>G variation, confirming the diagnosis of CACTD. Histopathologic analysis of the liver by Prussian blue staining showed focal iron deposition in hepatocytes, and electron microscopy analysis revealed a large number of lipid droplet vacuoles in diffusely distributed hepatocytes. Conclusion: The development of CACTD in our patient 61 days after birth is the latest reported onset for CACTD with SLC25A20 c.199-10T>G variation. Early recognition of symptoms and timely and appropriate treatment are critical for improving the outcome of this highly lethal disorder. Death from late-onset CACTD may be caused by the accumulation of long-chain fatty acids as well as iron deposition in the heart leading to heart failure.

The early diagnosis of Parkinson's disease through combined biomarkers

OBJECTIVE

This study primarily aims to explore the value of combining the measurement of plasma α-synuclein oligomer levels with enhanced T2 star-weighted angiography (ESWAN) in the early diagnosis of Parkinson's disease.

METHODS

Sixty patients with early Parkinson's disease and 30 normal adults, with similar ages and genders, were enrolled in the study. Their levels of plasma α-synuclein oligomers were measured, and ESWAN was performed. The amplitudes, phases and R2* values of the head, body and tail of the ipsilateral and contralateral substantia nigra pars compacta (SNc) were measured, at the side of the limb with severe symptoms or early symptoms. The receiver operating characteristic (ROC) curve was used to explore the value of these indexes in the early diagnosis of Parkinson's disease.

RESULTS

The plasma level of α-synuclein oligomer was significantly higher in the experimental group than in the control group (P < 0.05). The amplitude values of the head and tail of contralateral SNcs were significantly lower in the experimental group than in the control group (P < 0.05). In the single-index assessment, the serum α-synuclein oligomer had the highest specificity (70%), while the sensitivity of the amplitude of the head and tail of the contralateral SNc was 75% and 80%, respectively. The area under the curve, for the combination of these three indicators, was 0.827, diagnostic efficiency was particularly high, and sensitivity and specificity both reached 80%.

CONCLUSION

The combined detection of plasma α-synuclein oligomer and amplitude of the head and tail of the SNc has high diagnostic specificity and sensitivity.

Iron Deposition Leads to Hyperphosphorylation of Tau and Disruption of Insulin Signaling

Iron deposition in the brain is an early issue in Alzheimer's disease (AD). However, the pathogenesis of iron-induced pathological changes in AD remains elusive. Insulin resistance in brains is an essential feature of AD. Previous studies determined that insulin resistance is involved in the development of pathologies in AD. Tau pathology is one of most important hallmarks in AD and is associated with the impairment of cognition and clinical grades of the disease. In the present study, we observed that ferrous (Fe²⁺) chloride led to aberrant phosphorylation of tau, and decreased tyrosine phosphorylation levels of insulin receptor β (IRβ), insulin signal substrate 1 (IRS-1) and phosphoinositide 3-kinase p85α (PI3K p85α), in primary cultured neurons. In the in vivo studies using mice with supplemented dietary iron, learning and memory was impaired. As well, hyperphosphorylation of tau and disrupted insulin signaling in the brain was induced in iron-overloaded mice. Furthermore, in our in vitro work we identified the activation of insulin signaling following exogenous supplementation of insulin. This was further attenuated by iron-induced hyperphosphorylation of tau in primary neurons. Together, these data suggest that dysfunctional insulin signaling participates in iron-induced abnormal phosphorylation of tau in AD. Our study highlights the promising role of insulin signaling in pathological lesions induced by iron overloading.

Quantitative magnetic resonance imaging evaluation of hepatic fat content with iron deposition: will it be disturbed?

Objective

To explore noninvasive assessment of liver fat content with iron deposition using magnetic resonance (MR) quantitative technology.

Methods

A water–fat phantom with iron deposition containing 63 vials with predetermined fat percentages and iron concentrations was constructed. Thirty-three patients underwent fat quantitative MR examinations. The fat fraction (FF) was determined by three Dixon techniques. Pathological evaluation findings and the steatosis area rate (SAR) were used as the gold standards.

Results

FF_IOP and FF_LAVA-Flex significantly differed from FF_TEST for iron concentrations of 1 to 30 µg/mL and fat components of 10% to 80%. Using the three Dixon techniques, FF_IOP was 15.76% ± 6.98%, FF_LAVA-Flex was 16.71% ± 6.77%, and FF_{IDEAL IQ} was 13.18% ± 6.42% in patients without liver cirrhosis; these values in patients with liver cirrhosis were 20.35% ± 6.11%, 20.89% ± 8.49%, and 12.86% ± 4.00%, respectively. The SAR in patients without and with liver cirrhosis was 11.31% ± 5.89% and 9.84% ± 4.17%, respectively. There were significant positive correlations between FF_{IDEAL IQ} and SAR with or without liver cirrhosis.

Conclusion

Iron deposition must be considered when using quantitative MR techniques to evaluate the hepatic fat content. Compared with the IOP and LAVA-Flex techniques, the IDEAL IQ technique has more stability and accuracy in measurement of the hepatic fat content, free from iron deposition.

Brain iron deposition in primary insomnia-An in vivo susceptibility-weighted imaging study

BACKGROUND

To study the brain iron deposition and its relationships with cognitive impairment and sleep quality in primary insomnia (PI).

METHODS

Thirty-five patients with PI and 35 volunteers underwent MRI scanning using high-resolution susceptibility-weighted imaging sequence. Bilateral anterior cingulate cortices, posterior cingulate cortex, hippocampus, caudate nucleus, globus pallidus, putamen, thalamus, red nucleus, substantia nigra, parietal cortex, and frontal white matter were selected as regions of interest. The phase shift values of the above areas were compared between the two groups. Partial correlations between phase shifts values and neuropsychological scale scores including Pittsburgh Sleep Quality Index, Insomnia Severity Index, Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Activities of Daily Living Scale, and Clinical Dementia Rating of the PI patients were analyzed.

RESULTS

Compared with the normal controls, the PI patients showed significant lower MMSE and MoCA scores and increased phase shift values in the left caudate nucleus, left putamen, left hippocampus, and bilateral thalamus (p < 0.05). Close correlation was found between the phase shift value of the left hippocampus and the MMSE scores of the PI patients (R = -0.447, p < 0.01).

CONCLUSION

The PI patients exhibited significant cognitive impairment and increased iron deposition in several brain regions. The iron concentration of the left hippocampus is a biomarker of cognitive impairment and may play an important role in the pathophysiological mechanism.

Distinct Iron Deposition Profiles of Liver Zones in Various Models with Iron Homeostasis Disorders

Determination of iron accumulation is crucial in diagnosing the occurrence and progression of many liver- and iron-related diseases. Thus far, little is known about the profiles of iron deposition in different liver zones, particularly under conditions with disordered iron homeostasis. Here, uneven iron distribution in livers of patients with hereditary hemochromatosis (HH) is uncovered, showing the region with the highest iron concentration near the entrance site of the portal vein and hepatic artery in contrast to the sites with the lowest iron concentration close to the distal edge. Distinct iron distribution profiles are also found throughout liver zones in wild-type mice and various mouse models with iron metabolism disorders, including hemochromatosis (Hfe-/- ), iron deficiency, and inflammation. Of note, similar findings observed in HH patients are further demonstrated in Hfe-/- mice. Moreover, the zones with greater iron accumulation appear to be more sensitive to iron changes, e.g., there is iron increase upon iron overload and iron loss in response to iron deficiency. Mechanistic investigation manifests that these differential iron changes in liver zones are subjected to the regulation by the hepcidin-ferroportin axis. Additionally, the data corroborate the reliability of magnetic resonance imaging (MRI) in recognizing the differential iron deposition profiles among liver zones.

S-Nitrosylation of Divalent Metal Transporter 1 Enhances Iron Uptake to Mediate Loss of Dopaminergic Neurons and Motoric Deficit

Elevated iron deposition has been reported in Parkinson's disease (PD). However, the route of iron uptake leading to high deposition in the substantia nigra is unresolved. Here, we show a mechanism in enhanced Fe²⁺ uptake via S-nitrosylation of divalent metal transporter 1 (DMT1). While DMT1 could be S-nitrosylated by exogenous nitric oxide donors, in human PD brains, endogenously S-nitrosylated DMT1 was detected in postmortem substantia nigra. Patch-clamp electrophysiological recordings and iron uptake assays confirmed increased Mn²⁺ or Fe²⁺ uptake through S-nitrosylated DMT1. We identified two major S-nitrosylation sites, C23 and C540, by mass spectrometry, and DMT1 C23A or C540A substitutions abolished nitric oxide (NO)-mediated DMT1 current increase. To evaluate in vivo significance, lipopolysaccharide (LPS) was stereotaxically injected into the substantia nigra of female and male mice to induce inflammation and production of NO. The intranigral LPS injection resulted in corresponding increase in Fe²⁺ deposition, JNK activation, dopaminergic neuronal loss and deficit in motoric activity, and these were rescued by the NO synthase inhibitor l-NAME or by the DMT1-selective blocker ebselen. Lentiviral knockdown of DMT1 abolished LPS-induced dopaminergic neuron loss.SIGNIFICANCE STATEMENT Neuroinflammation and high cytoplasmic Fe²⁺ levels have been implicated in the initiation and progression of neurodegenerative diseases. Here, we report the unexpected enhancement of the functional activity of transmembrane divalent metal transporter 1 (DMT1) by S-nitrosylation. We demonstrated that S-nitrosylation increased DMT1-mediated Fe²⁺ uptake, and two cysteines were identified by mass spectrometry to be the sites for S-nitrosylation and for enhanced iron uptake. One conceptual advance is that while DMT1 activity could be increased by external acidification because the gating of the DMT1 transporter is proton motive, we discovered that DMT1 activity could also be enhanced by S-nitrosylation. Significantly, lipopolysaccharide-induced nitric oxide (NO)-mediated neuronal death in the substantia nigra could be ameliorated by using l-NAME, a NO synthase inhibitor, or by ebselen, a DMT1-selective blocker.

Evidence that iron accelerates Alzheimer's pathology: a CSF biomarker study

OBJECTIVE

To investigate whether cerebrospinal fluid (CSF) ferritin (reporting brain iron) is associated with longitudinal changes in CSF β-amyloid (Aβ) and tau.

METHODS

Mixed-effects models of CSF Aβ_1-42 and tau were constructed using data from 296 participants who had baseline measurement of CSF ferritin and annual measurement of CSF tau and Aβ_1-42 for up to 5 years.

RESULTS

In subjects with biomarker-confirmed Alzheimer's pathology, high CSF ferritin (>6.2 ng/mL) was associated with accelerated depreciation of CSF Aβ_1-42 (reporting increased plaque formation; p=0.0001). CSF ferritin was neither associated with changes in CSF tau in the same subjects, nor longitudinal changes in CSF tau or Aβ_1-42 in subjects with low baseline pathology. In simulation modelling of the natural history of Aβ deposition, which we estimated to occur over 31.4 years, we predicted that it would take 12.6 years to reach the pathology threshold value of CSF Aβ from healthy normal levels, and this interval is not affected by CSF ferritin. CSF ferritin influences the fall in CSF Aβ over the next phase, where high CSF ferritin accelerated the transition from threshold preclinical Aβ levels to the average level of Alzheimer's subjects from 18.8 to 10.8 years.

CONCLUSIONS

Iron might facilitate Aβ deposition in Alzheimer's and accelerate the disease process.

Relationship between T2* magnetic resonance imaging-derived liver and heart iron content and serum ferritin levels in transfusion-dependent thalassemic children

CONTEXT:

T2* magnetic resonance imaging (MRI) is being increasingly used for the assessment of organ iron content in thalassemics, but cost is a major prohibitive factor for repeated measurements. If serum ferritin correlates well with the T2* MRI liver and heart, it will be economical and more simple tool to assess organ iron deposition.

AIMS:

The aim of this study was to find out the relationship between serum ferritin level and T2* MRI-derived liver and heart iron content in transfusion-dependent thalassemic children

SETTINGS:

Thalassemia day-care center of a teaching hospital

DESIGN:

This was a cross-sectional study

SUBJECTS AND METHODS:

Seventy-three transfusion-dependent beta thalassemic children belonging to 2–18 years of age were subjected to T2* MRI of heart and liver to assess their iron content. Values obtained here were related to serum ferritin.

STATISTICAL ANALYSIS USED:

Keeping the correlation between serum ferritin and T2* MRI as primary outcome, spearman's correlation coefficient was calculated.

RESULTS:

We found poor (negative) correlation between serum ferritin level and T2* MRI liver (r = -0.448, P = 0.000) but no correlation between serum ferritin and T2*MRI heart (r = -0.221, P = 0.060).

Conclusions:

Serum ferritin cannot reliably predict the liver and heart iron content in Indian children with β thalassemia.

An autopsy case of globular glial tauopathy presenting with clinical features of motor neuron disease with dementia and iron deposition in the motor cortex

Globular glial tauopathy (GGT) is a 4-repeat (4R) tauopathy in which 4R tau accumulates to form globular glial inclusions (GGIs), predominantly in oligodendroglia. To date, little has been reported on iron deposits in patients with GGT. We report a case of GGT with iron deposits in a 78-year-old woman presenting with an 8-year history of slowly progressing limb weakness and cognitive decline. Susceptibility-weighted imaging revealed a low signal intensity in the right precentral gyrus, suggesting iron deposition. A clinical diagnosis of motor neuron disease with dementia was made 4 years after onset. At autopsy, gross pathological findings showed atrophy of the frontal and temporal lobes. A localized area of the precentral gyrus corresponding to the most severely affected limb showed the strongest atrophy, macroscopically, and displayed 4R tau-immunoreactive GGIs and microscopically many ferritin-immunoreactive neurons. We diagnosed this patient as having GGT. This is the first GGT case with iron deposition confirmed both radiologically and pathologically.

Long-term sequelae of hippocampal lesions in patients with transient global amnesia: A multiparametric MRI study

BACKGROUND

MRI signal diffusion-weighted imaging (DWI) hyperintensity in the hippocampus in patients with transient global amnesia (TGA) are resolved within several days after the onset of TGA.

PURPOSE

To use multiparametric MRI to unravel the sequelae of TGA.

STUDY TYPE

A prospective longitudinal study.

POPULATION

Eight TGA patients.

FIELD STRENGTH/SEQUENCE

A 3.0T Siemens Tim Trio MRI scanner with T₁ -weighted MPRAGE, diffusion-weighted echo planar imaging, and multiecho gradient-recalled echo sequences.

ASSESSMENT

Brain MRI scanned within 72 hours, 2 weeks, and 3 months after onset of TGA, respectively. T₁ image hippocampus was first segmented into 12 subregions using FreeSurfer and registered to DWI to locate DWI lesion. Then a T₁ image with segmented hippocampus was registered to its corresponding apparent diffusion coefficient (ADC) map, fractional anisotropy (FA) map, and quantitative susceptibility map, respectively. Finally, the volume, water diffusion and anisotropy, and magnetic susceptibility of DWI lesion were analyzed.

STATISTICAL TESTS

A paired samples t-test was performed to detect measurement differences between three tests. Pearson correlation was used to assess the correlations between all measurements.

RESULTS

Hyperintensity was detected in the head, body, and caudate of CA1 and hippocampal tail. No significant changes existed in CA1/unit volume across the three timepoint measurements (all, P > 0.480). In Test 1, ratio ADC (DWI lesion / adjacent healthy, rADC) and ratio FA (rFA) decreased below, while ratio susceptibility increased above 1.0. In Test 2, all the episodes normalized around 1.0. In Test 3, rADC remained normalization, but rFA decreased and ratio susceptibility increased again. In Test 1 and Test 3 (vs. Test 2), decreased FA values were accompanied with lower axial diffusivity and/or higher radial diffusivity (all, P < 0.001). Moreover, rFA significantly correlated with ratio susceptibility in Test 3 (r = -0.665, P = 0.039).

DATA CONCLUSION

Microstructural sequelae in hippocampus were demonstrated, which indicates that ischemic lesions may be associated with TGA.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1350-1358.

Assessment of advanced hepatic MR elastography methods for susceptibility artifact suppression in clinical patients

PURPOSE

To assess the success rate, image quality, and the ability to stage liver fibrosis of a standard 2D gradient-recalled echo (GRE) and four different spin-echo (SE) magnetic resonance elastography (MRE) sequences in patients with different liver iron concentrations.

MATERIALS AND METHODS

A total of 332 patients who underwent 3T MRE examinations that included liver fat and iron quantification were enrolled, including 136 patients with all five MRE techniques. Thirty-four patients had biopsy results for fibrosis staging. The liver stiffness, region of interest area, image quality, and success rate of the five sequences were compared in 115/136 patients. The area under the receiver operating characteristic curves (AUCs) and the accuracies for diagnosing early-stage fibrosis and advanced fibrosis were compared. The effect of BMI (body mass index), the R2* relaxation time, and fat fraction on the image quality and liver stiffness measurements were analyzed.

RESULTS

The success rates were significantly higher in the four SE sequences (99.1-100%) compared with GRE MRE (85.3%) (all P < 0.001). There were significant differences of the mean ROI area between every pair of sequences (all P < 0.0001). There were no significant differences in the AUC of the five MRE sequences for discriminating advanced fibrosis (10 P-values ranging from 0.2410-0.9171). R2* had a significant effect on the success rate and image quality for the noniron 2D echo-planar imaging (EPI), 3D EPI and 2D GRE (all P < 0.001) sequences. BMI had a significant effect on the iron 2D EPI (P = 0.0230) and iron 2D SE (P = 0.0040) sequences.

CONCLUSION

All five techniques showed good diagnostic performance in staging liver fibrosis. The SE MRE sequences had higher success rates and better image quality than GRE MRE in 3T clinical hepatic imaging.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:976-987.

Dentate nucleus iron deposition is a potential biomarker for tremor-dominant Parkinson's disease

Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder with variable clinicopathologic phenotypes and underlying neuropathologic mechanisms. Each clinical phenotype has a unique set of motor symptoms. Tremor is the most frequent initial motor symptom of PD and is the most difficult symptom to treat. The dentate nucleus (DN) is a deep iron-rich nucleus in the cerebellum and may be involved in PD tremor. In this study, we test the hypothesis that DN iron may be elevated in tremor-dominant PD patients using quantitative susceptibility mapping. Forty-three patients with PD [19 tremor dominant (TD)/24 akinetic rigidity (AR) dominant] and 48 healthy gender- and age-matched controls were recruited. Multi-echo gradient echo data were collected for each subject on a 3.0-T MR system. Inter-group susceptibility differences in the bilateral DN were investigated and correlations of clinical features with susceptibility were also examined. In contrast with the AR-dominant group, the TD group was found to have increased susceptibility in the bilateral DN when compared with healthy controls. In addition, susceptibility was positively correlated with tremor score in drug-naive PD patients. These findings indicate that iron load within the DN may make an important contribution to motor phenotypes in PD. Moreover, our results suggest that TD and AR-dominant phenotypes of PD can be differentiated on the basis of the susceptibility of the DN, at least at the group level. Copyright © 2016 John Wiley & Sons, Ltd.