Chronic Traumatic Encephalopathy in Soccer Players: Review of 14 Cases.

OBJECTIVE: Exposure to repetitive sports-related concussions or (sub)concussive head trauma may lead to chronic traumatic encephalopathy (CTE). Which impact (heading or concussion) poses the greatest risk of CTE development in soccer players? DESIGN: Narrative review. SETTING: Teaching hospital and University of Applied sciences. PATIENTS: A literature search (PubMed) was conducted for neuropathologic studies in the period 2005-December 2022, investigating soccer players with dementia and a CTE diagnosis, limited to English language publications. 210 papers were selected for final inclusion, of which 7 papers described 14 soccer players. ASSESSMENT: Magnetic resonance imaging studies in soccer players show that lifetime estimates of heading numbers are inversely correlated with cortical thickness, grey matter volume, and density of the anterior temporal cortex. Using diffusion tensor imaging-magnetic resonance imaging, higher frequency of headings-particularly with rotational accelerations-are associated with impaired white matter integrity. Serum neurofilament light protein is elevated after heading. MAIN OUTCOME MEASURES: Chronic traumatic encephalopathy pathology, history of concussion, heading frequency. RESULTS: In 10 of 14 soccer players, CTE was the primary diagnosis. In 4 cases, other dementia types formed the primary diagnosis and CTE pathology was a concomitant finding. Remarkably, 6 of the 14 cases had no history of concussion, suggesting that frequent heading may be a risk for CTE in patients without symptomatic concussion. Rule changes in heading duels, management of concussion during the game, and limiting the number of high force headers during training are discussed. CONCLUSIONS: Data suggest that heading frequency and concussions are associated with higher risk of developing CTE in (retired) soccer players. However based on this review of only 14 players, questions persist as to whether or not heading is a risk factor for CTE or long-term cognitive decline.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Neuroimaging.

BACKGROUND: Over the past 5 decades, advances in neuroimaging have yielded insights into the pathophysiologic mechanisms that cause disorders of consciousness (DoC) in patients with severe brain injuries. Structural, functional, metabolic, and perfusion imaging studies have revealed specific neuroanatomic regions, such as the brainstem tegmentum, thalamus, posterior cingulate cortex, medial prefrontal cortex, and occipital cortex, where lesions correlate with the current or future state of consciousness. Advanced imaging modalities, such as diffusion tensor imaging, resting-state functional magnetic resonance imaging (fMRI), and task-based fMRI, have been used to improve the accuracy of diagnosis and long-term prognosis, culminating in the endorsement of fMRI for the clinical evaluation of patients with DoC in the 2018 US (task-based fMRI) and 2020 European (task-based and resting-state fMRI) guidelines. As diverse neuroimaging techniques are increasingly used for patients with DoC in research and clinical settings, the need for a standardized approach to reporting results is clear. The success of future multicenter collaborations and international trials fundamentally depends on the implementation of a shared nomenclature and infrastructure. METHODS: To address this need, the Neurocritical Care Society's Curing Coma Campaign convened an international panel of DoC neuroimaging experts to propose common data elements (CDEs) for data collection and reporting in this field. RESULTS: We report the recommendations of this CDE development panel and disseminate CDEs to be used in neuroimaging studies of patients with DoC. CONCLUSIONS: These CDEs will support progress in the field of DoC neuroimaging and facilitate international collaboration.

Review of neuroimaging research progress of cerebral small vessel disease.

Cerebral small vessel disease (cSVD) is a disease defined by clinical symptoms and neuroimaging, which often causes a series of pathophysiological changes, blood-brain barrier destruction, brain tissue ischemia and involves cerebral arterioles, capillaries and venules. The exact pathogenesis of cSVD is unclear and there is no specific prevention and treatment for this potentially high disability rate disease. This article reviewed the latest research progress of neuroimaging of cSVD in order to improve our understanding of cSVD's manifestation and potential mechanism. We introduced the neuroimaging markers which can be accurately identified by diffusion tensor imaging, including recent subcortical infarction, white matter lesions, brain atrophy, lacunar infarction, cerebral microhaemorrhage and other cSVD neuroimaging markers. Besides, we also interpreted the total load score of cSVD, which described a wide range of clinical, pathological and neuroimaging features, reflecting the acute and chronic damage of the whole brain. Combined with the neuroimaging methods, capturing the imaging features of early cSVD can improve the diagnostic ability of cSVD and provide strong support for the longitudinal study.

Comparative analysis of freezing of gait in distinct Parkinsonism types by diffusion tensor imaging method and cognitive profiles.

Freezing of gait (FOG) is an episodic gait pattern that is common in advanced Parkinson's disease (PD) and other atypical parkinsonism syndromes. Recently, disturbances in the pedunculopontine nucleus (PPN) and its connections have been suggested to play a critical role in the development of FOG. In this study, we aimed to demonstrate possible disturbances in PPN and its connections by performing the diffusion tensor imaging (DTI) technique. We included 18 patients of PD with FOG [PD-FOG], 13 patients of PD without FOG [PD-nFOG] and 12 healthy subjects as well as a group of patients with progressive supranuclear palsy (PSP), an atypical parkinsonism syndrome which is very often complicated with FOG [6 PSP-FOG, 5 PSP-nFOG]. To determine the specific cognitive parameters that can be related to FOG, deliberate neurophysiological evaluations of all the individuals were performed. The comparative analyses and correlation analyses were performed to reveal the neurophysiological and DTI correlates of FOG in either group. We have found disturbances in values reflecting microstructural integrity of the bilateral superior frontal gyrus (SFG), bilateral fastigial nucleus (FN), left pre-supplementary motor area (SMA) in the PD-FOG group relative to the PD-nFOG group. The analysis of the PSP group also demonstrated disturbance in left pre-SMA values in the PSP-FOG group likewise, while negative correlations were determined between right STN, left PPN values and FOG scores. In neurophysiological assessments, lower performances for visuospatial functions were demonstrated in FOG ( +) individuals for either patient group. The disturbances in the visuospatial abilities may be a critical step for the occurrence of FOG. Together with the results of DTI analyses, it might be suggested that impairment in the connectivity of disturbed frontal areas with disordered basal ganglia, maybe the key factor for the occurrence of FOG in the PD group, whereas left PPN which is a nondopaminergic nucleus may play a more prominent role in the process of FOG in PSP. Moreover, our results support the relationship between right STN, and FOG as mentioned before, as well as introduce the importance of FN as a new structure that may be involved in FOG pathogenesis.

Pediatric abusive head trauma: visual outcomes, evoked potentials, diffusion tensor imaging, and relationships to retinal hemorrhages.

PURPOSE: Function and anatomy of the visual system were evaluated in children with abusive head trauma (AHT). The relationships between retinal hemorrhages at presentation were examined with outcome measures. METHODS: Retrospective review of data in children with AHT for 1) visual acuity at last follow-up, 2) visual evoked potentials (VEP) after recovery, 3) diffusion metrics of white matter tracts and grey matter within the occipital lobe on diffusion tensor imaging (DTI), and 4) patterns of retinal hemorrhages at presentation. Visual acuity was converted into logarithm of minimum angle of resolution (logMAR) after correction for age. VEPs were also scored by objective signal-to-noise ratio (SNR). RESULTS: Of 202 AHT victims reviewed, 45 met inclusion criteria. Median logMAR was reduced to 0.8 (approximately 20/125 Snellen equivalent), with 27% having no measurable vision. Thirty-two percent of subjects had no detectable VEP signal. VEPs were significantly reduced in subjects initially presenting with traumatic retinoschisis or hemorrhages involving the macula (p < 0.01). DTI tract volumes were decreased in AHT subjects compared to controls (p < 0.001). DTI metrics were most affected in AHT victims showing macular abnormalities on follow-up ocular examination. However, DTI metrics were not correlated with visual acuity or VEPS. There was large inter-subject variability within each grouping. DISCUSSION: Mechanisms causing traumatic retinoschisis, or traumatic abnormalities of the macula, are associated with significant long-term visual pathway dysfunction. AHT associated abnormalities of the macula, and visual cortical pathways were more fully captured by VEPs than visual acuity or DTI metrics.

Cerebral small vessel disease: Recent advances and future directions.

Cerebral small vessel disease (SVD) causes lacunar stroke and intracerebral hemorrhage, and is the most common pathology underlying vascular cognitive impairment. Increasingly, the importance of other clinical features of SVD is being recognized including motor impairment, (vascular) parkinsonism, impaired balance, falls, and behavioral symptoms, such as depression, apathy, and personality change. Epidemiological data show a high prevalence of the characteristic magnetic resonance imaging (MRI) features of white matter hyperintensities and lacunar infarcts in community studies, and recent data suggest that it is also a major health burden in low- and middle-income countries. In this review, we cover advances in diagnosis, imaging, clinical presentations, pathogenesis, and treatment.The two most common pathologies underlying SVD are arteriolosclerosis caused by aging, hypertension, and other conventional vascular risk factors, and cerebral amyloid angiopathy (CAA) caused by vascular deposition of ß-amyloid. We discuss the revised Boston criteria of CAA based on MRI features, which have been recently validated. Imaging is providing important insights into pathogenesis, including improved detection of tissue damage using diffusion tensor imaging (DTI) leading to its use to monitor progression and surrogate endpoints in clinical trials. Advanced MRI techniques can demonstrate functional or dynamic abnormalities of the blood vessels, while the high spatial resolution provided by ultrahigh field MRI at 7 T allows imaging of individual perforating arteries for the first time, and the measurement of flow velocity and pulsatility within these arteries. DTI and structural network analysis have highlighted the importance of network disruption in mediating the effect of different SVD pathologies in causing a number of symptoms, including cognitive impairment, apathy, and gait disturbance.Despite the public health importance of SVD, there are few proven treatments. We review the evidence for primary prevention, and recent data showing how intensive blood pressure lowering reduces white matter hyperintensities (WMH) progression and delays the onset of cognitive impairment. There are few treatments for secondary prevention, but a number of trials are currently evaluating novel treatment approaches. Recent advances have implicated molecular processes related to endothelial dysfunction, nitric oxide synthesis, blood-brain barrier integrity, maintenance and repair of the extracellular matrix, and inflammation. Novel treatment approaches are being developed to a number of these targets. Finally, we highlight the importance of large International collaborative initiatives in SVD to address important research questions and cover a number which have recently been established.

Normal Pancreas Graft Appearance in Magnetic Resonance Diffusion Tensor Imaging (DTI).

BACKGROUND The main purpose of diagnostic imaging after pancreas transplantation is to exclude potential complications. As long as standard anatomical imaging such as sonography, contrast-enhanced computed tomography, and magnetic resonance imaging (MRI) are sufficient to display macroscopic vasculature, early changes within the graft caused by insufficient microperfusion will not be displayed for evaluation. MATERIAL AND METHODS Patients with pancreas allograft function in good condition were included in the study. No specific preparation was demanded before the MRI examination. The results of MRI were correlated with Igls criteria. It was a preliminary study to examine diffusion tensor imaging (DTI) value and safety in pancreas transplantation. RESULTS Our results indicated that higher fractional anisotropy (FA) values of the graft's head were associated with delayed graft function and insulin intake. We also compared grafts' images in early and late periods and found differences in T1 signal intensity values. DTI is a reliable noninvasive tool, requiring no contrast agent, to assess graft microstructure in correlation with its function, with FA values showing the most consistent results. By Igls criteria, no graft failure, 76% had optimal function, 10% had good function, and 14% had marginal function. CONCLUSIONS Our results suggest that DTI can be safely used in patients after pancreas transplantation and is advantageous in detecting early as well as late postoperative complications such as intra-abdominal fluid collection, malperfusion, and ischemia of the graft. Our findings correspond with clinical condition and Igls criteria. DTI is free of ionizing agents and is safe for kidney grafts.

Towards safe operation of an active retinal prosthesis during functional MRI and diffusion tensor imaging.

OBJECTIVE: To determine if the Argus II retinal prosthesis can operate during functional MRI (fMRI) and diffusion tensor imaging (DTI) acquisitions and if currents induced in the prosthesis by imaging are at safe levels. MATERIALS AND METHODS: One Argus II retinal prosthesis was modified to enable current measurements during imaging. Active electronics were modified to enable operation during scans. Induced current was measured during diagnostic scans, which were previously shown to be safe for implanted patients, and during fMRI and DTI scans. All measurements were performed using an ASTM phantom to ensure reproducible placement. RESULTS: The prosthesis was able to maintain communication with the external RF coil during the fMRI and DTI scans except briefly during pre-scans. Current levels induced during fMRI and DTI scans were consistently below those measured during diagnostic scans. CONCLUSIONS: fMRI and DTI may be safely performed while the Argus II retinal prosthesis is operating.

The evolving utility of diffusion tensor tractography in the surgical management of temporal lobe epilepsy: a review.

BACKGROUND: Diffusion tensor imaging (DTI) is a relatively new imaging modality that has found many peri-operative applications in neurosurgery. METHODS: A comprehensive survey of the applications of diffusion tensor imaging (DTI) in planning for temporal lobe epilepsy surgery was conducted. The presentation of this literature is supplemented by a case illustration. RESULTS: The authors have found that DTI is well utilized in epilepsy surgery, primarily in the tractography of Meyer's loop. DTI has also been used to demonstrate extratemporal connections that may be responsible for surgical failure as well as perioperative planning. The tractographic anatomy of the temporal lobe is discussed and presented with original DTI pictures. CONCLUSIONS: The uses of DTI in epilepsy surgery are varied and rapidly evolving. A discussion of the technology, its limitations, and its applications is well warranted and presented in this article.

Diffusion tensor imaging findings of optic radiation in patients with putaminal hemorrhage.

OBJECTIVES: Little is known about optic radiation (OR) injury in intracerebral hemorrhage (ICH). We attempted to investigate OR injury in patients with ICH by diffusion tensor imaging (DTI). METHODS: Forty-three consecutive patients with putaminal hemorrhage and 40 normal healthy control subjects were recruited. DTI data were acquired at the beginning of rehabilitation (average 34 days after onset). DTI-Studio software was used to reconstruct the OR. Fractional anisotropies (FA) and fiber numbers of the ORs were measured. FA values and fiber numbers of affected ORs were described as abnormal when they were more than 2.5 SD lower than those of normal controls. RESULTS: Thirty (70%) of the 43 patients showed an OR abnormality in the affected hemisphere. In 13 (30%) patients, the affected OR was disrupted or nonreconstructable. On the other hand, of the 20 patients with preserved OR integrity, 14 (33%) had a low FA value and 3 (7%) a low FA and fiber number. The other 13 (30%) of the 43 patients had no abnormal OR findings. CONCLUSION: Seventy percent of patients showed any abnormality of OR in the affected hemisphere on DTI. This result suggests that patients with putaminal hemorrhage are at high risk of OR injury.

Optic radiation injury in a patient with traumatic brain injury.

PRIMARY OBJECTIVE: This study reports on a patient who showed an optic radiation (OR) injury on diffusion tensor imaging (DTI) following head trauma. The patient, who had suffered a traffic accident, underwent conservative management for diffuse axonal injury and contusions in the left midbrain, temporal lobe and anterior to mid-portion of left OR. He complained of right homonymous hemianopsia from the onset of TBI and right bilateral homonymous hemianopsia was detected at the 6-month Humphrey visual field test. METHODS AND PROCEDURES: A 20 year-old man with traumatic brain injury (TBI) and eight age-matched normal subjects were recruited for this study. MAIN OUTCOMES AND RESULTS: The left OR of the patient showed a discontinuation around the mid-portion. The FA (fractional anisotropy) values of the posterior portions of left OR decreased over two standard deviations of normal controls, but the ADC (apparent diffusion coefficient) values of these sites increased over two standard deviations of normal controls. CONCLUSIONS: Consequently, it was assumed that the main injury site of the left OR was located around the posterior portion of the left OR. This results suggest that DTI may be a useful technique for detection of an OR injury in patients with TBI.

Delineation of the safe zone in surgery of sylvian insular triangle: morphometric analysis and magnetic resonance imaging study.

BACKGROUND: Surgery within the insula carries significant risk of morbidity, particularly hemiparesis, because of the difficulty in detecting the internal capsule boundaries. OBJECTIVE: We analyzed the anatomy of the insula and identified landmarks anticipated to facilitate surgery for intrinsic insular lesions. METHODS: Insular region anatomy was studied in 11 cadaveric brains harvested within 72 hours postmortem. MRI of the specimens was acquired using 3.0 T with T2-weighting and 25 directions of diffusion tensor imaging. Landmarks easily recognizable during surgery were identified on the surface of the insula. The interrelationships between surface landmarks and critical structures were analyzed. RESULTS: The posterior inferior insular point (PIIP) and the upper central insular point (UCIP) were newly established as landmarks on the insula. The PIIP corresponded to the obvious bend in the posterior long insular gyrus. The UCIP is the meeting point between the central insular sulcus and superior peri-insular sulcus. The corticospinal tract was identified as a high-intensity area in the posterior limb of the internal capsule on T2-weighted imaging and its course confirmed with diffusion tensor imaging tractography. The corticospinal tract took a course deep to the posterosuperior insula on T2-weighted imaging, 4.8 mm from the UCIP and 6.2 mm from the PIIP. CONCLUSION: The posterosuperior part of the insula forms the region at greatest risk to corticospinal tract injury. The PIIP and UCIP are crucial to understanding the relationship of the insula with the posterior limb of the internal capsule including the corticospinal tract.

Optic radiation injury following traumatic epidural hematoma: Diffusion tensor imaging study.

Little is known about optic radiation (OR) injury in patients with traumatic brain injury (TBI). We report on a patient who showed an OR injury on diffusion tensor imaging (DTI) following traumatic epidural hematoma (EDH). A 38 year-old man with TBI and 7 age-matched normal subjects were enrolled in this study. The patient had fallen down stairs while in an alcohol intoxicated state. He underwent a craniotomy following diagnosis of traumatic EDH in the left temporo-parietal lobe on brain CT. He complained of right bilateral homonymous hemianopsia, which was confirmed on the Humphrey visual field test. No lesion on the left OR was observed during brain MRI. We were not able to reconstruct the fiber tractography for the left OR in this patient. We found that the left OR had been injured most severely around the midportion between the lateral geniculate body and occipital pole. We determined that DTI would be a useful technique for detection of an OR injury in patients with TBI. Therefore, we believe that DTI should be performed along with conventional brain MRI for patients with visual field defects following TBI.