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Background: Persistent symptoms have been reported in up to 50% of the 27 million people with mild traumatic brain injuries (mTBI) every year. MRI findings are currently limited by low diagnostic and prognostic sensitivities, constraining the value of imaging in the stratification of patients following mTBI. Limbic system structures are promising brain regions in offering prognostic factors for symptom persistence following mTBI. The objective of this study was to associate volume and symmetry of limbic system structures with the presence and persistence of common symptoms in patients with mTBI. Methods: This study focused on 524 adults (aged 18-82), 58% female, with 82% injured in motor vehicle accidents and 28% reporting loss of consciousness (LOC). Magnetic resonance imaging (MRI) data included a sagittal 3D T1-weighted sequence with 1.2 mm slice thickness, with voxel sizes of 0.93 mm × 0.93 mm × 1.2 mm, obtained a median of 156 days after injury. Symptom diagnosis and persistence were collected retrospectively from patient medical records. Intracranial volume-adjusted regional volumes per side utilizing automated volumetric analysis (NeuroQuant®) were used to calculate total volume, laterality index, and side-independent asymmetry. Covariates included age, sex, LOC, and days from injury. Limbic volumetrics did not relate to symptom presentation, except the (-) association between headache presence and thalamus volume (adjusted odds ratio = 0.51, 95% confidence interval = 0.32, 0.85). Headache, balance problems, anxiety, and depression persistence was (-) associated with thalamus volume (hazard ratio (HR) 1.25 to 1.94). Longer persistence of balance problems was associated with (-) lateral orbitofrontal cortex volume (HR = 1.33) and (+) asymmetry of the hippocampus (HR = 0.27). Persistence of cognitive deficits was associated with (+) asymmetry in the caudal anterior cingulate (HR = 0.67). Depression persistence was associated with (+) asymmetry in the isthmus of the cingulate gyrus (HR = 5.39). Persistence of anxiety was associated with (-) volume of the parahippocampal gyrus (HR = 1.67), orbitofrontal cortex (HR > 1.97), and right-biased laterality of the entorhinal cortex (HR = 0.52). Conclusions: Relative volume and asymmetry of the limbic system structures in patients with mTBI are associated with the persistence of symptoms, particularly anxiety. The conclusions of this study are limited by the absence of a reference group with no mTBI.
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Background: Mild traumatic brain injuries (mTBIs) comprise 80% of all TBI, but conventional MRI techniques are often insensitive to the subtle changes and injuries produced in a concussion. Diffusion tensor imaging (DTI) is one of the most sensitive MRI techniques for mTBI studies with outcome and symptom associations described. The corpus callosum (CC) is one of the most studied fiber tracts in TBI and mTBI, but the comprehensive post-mTBI symptom relationship has not fully been explored. Methods: This is a retrospective observational study of how quantitative DTI data of the CC and its sub-regions may relate to clinical presentation of symptoms and timing of resolution of symptoms in patients diagnosed with uncomplicated mTBI. DTI and clinical data were obtained retrospectively from 446 (mean age 42 years, range 13-82) civilian patients. From patient medical charts, presentation of the following common post-concussive symptoms was noted: headache, balance issues, cognitive deficits, fatigue, anxiety, depression, and emotional lability. Also recorded was the time between injury and a visit to the physician when improvement or resolution of a particular symptom was reported. FA values from the total CC and 3 subregions of the CC (genu or anterior, mid body, and splenium or posterior) were obtained from hand tracing on the Olea Sphere v3.0 SP12 free-standing workstation. DTI data was obtained from 8 different 3T MRI scanners and harmonized via ComBat harmonization. The statistical models used to explore the association between regional Fractional Anisotropy (FA) values and symptom presentation and time to symptom resolution were logistic regression and interval-censored semi-parametric Cox proportional hazard models, respectively. Subgroups related to age and timing of first scan were also analyzed. Results: Patients with the highest FA in the total CC (p = 0.01), anterior CC (p < 0.01), and mid-body CC (p = 0.03), but not the posterior CC (p = 0.91) recovered faster from post-concussive cognitive deficits. Patients with the highest FA in the posterior CC recovered faster from depression (p = 0.04) and emotional lability (p = 0.01). There was no evidence that FA in the CC or any of its sub-regions was associated with symptom presentation or with time to resolution of headache, balance issues, fatigue, or anxiety. Patients with mTBI under 40 had higher FA in the CC and the anterior and mid-body subregions (but not the posterior subregion: p = 1.00) compared to patients 40 or over (p ≤ 0.01). There was no evidence for differences in symptom presentation based on loss of consciousness (LOC) or sex (p ≥ 0.18). Conclusion: This study suggests that FA of the CC has diagnostic and prognostic value for clinical assessment of mTBI in a large diverse civilian population, particularly in patients with cognitive symptoms.
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BACKGROUND. Ulnar collateral ligament (UCL) injuries are common in throwing athletes owing to repetitive extreme valgus stress during overhead throwing maneuvers. Conventional positioning for elbow MRI provides suboptimal rendering of the UCL. OBJECTIVE. The purpose of this prospective pilot study was to assess the effect of flexed elbow valgus external rotation (FEVER) on ulnotrochlear joint space measurement and reader evaluation of the UCL when the FEVER view is incorporated into standard elbow MRI of throwing athletes. METHODS. A total of 44 Major League Baseball pitchers underwent elbow MRI including standard sequences and a coronal fat-saturated proton density-weighted sequence in the FEVER view. To achieve the FEVER view, specific positioning maneuvers are performed, and sandbags are placed to immobilize the elbow in valgus stress so that the UCL can be visualized parallel to its long axis. Patients recorded pain during FEVER on a scale of 0 (none) to 10 (maximal). Two radiologists independently evaluated standard and FEVER images to measure the ulnotrochlear joint space, assess confidence in UCL-related findings, and assess the UCL as normal or abnormal. RESULTS. Pain during FEVER was rated 0 by 29 patients, 1-3 by 11 patients, 4-7 by four patients, and 8-10 by no patients. Intrareader agreement on ulnotrochlear joint space measurement was higher for FEVER (intraclass correlation coefficient [ICC], 0.92) than standard (ICC, 0.54) views. Averaged between readers, the mean increase in ulnotrochlear joint space in the FEVER compared with the standard view was 1.80 mm (95% CI, 1.58-2.03). Confidence was higher for the FEVER than for the standard view for reader 1 in assessment of the UCL as normal versus abnormal (mean increase in confidence, 0.40), intensity of abnormal signal (0.39), injury grade (1.04), and retraction (0.25) and for reader 2 in assessment of the UCL as normal versus abnormal (0.50), location of abnormal signal (0.46), intensity of abnormal signal (0.51), injury grade (0.96), and retraction (0.53). Readers 1 and 2 classified three and two additional UCLs as abnormal on FEVER view compared with standard view images; neither reader classified any UCL as abnormal on standard view but normal on FEVER view images. CONCLUSION. The increased joint space width confirmed elbow valgus stress in the FEVER view. Diagnostic confidence increased, and additional UCLs were identified as abnormal. CLINICAL IMPACT. Use of the FEVER view may improve MRI evaluation of the UCL in throwing athletes.