Multimodal Neuroimaging Differences in Nicotine Abstinent Smokers Versus Satiated Smokers.

INTRODUCTION: Research on cigarette smokers suggests cognitive and behavioral impairments. However, much remains unclear how the functional neurobiology of smokers is influenced by nicotine state. Therefore, we sought to determine which state, be it acute nicotine abstinence or satiety, would yield the most robust differences compared with nonsmokers when assessing neurobiological markers of nicotine dependence. METHODS: Smokers (N = 15) and sociodemographically matched nonsmokers (N = 15) were scanned twice using a repeated-measures design. Smokers were scanned after a 24-hour nicotine abstinence and immediately after smoking their usual brand cigarette. The neuroimaging battery included a stop-signal task of response inhibition and pseudocontinuous arterial spin labeling to measure cerebral blood flow (CBF). Whole-brain voxel-wise analyses of covariance were carried out on stop success and stop fail Stop-Signal Task contrasts and CBF maps to assess differences among nonsmokers, abstinent smokers, and satiated smokers. Cluster correction was performed using AFNI's 3dClustSim to achieve a significance of p < .05. RESULTS: Smokers exhibited higher brain activation in bilateral inferior frontal gyrus, a brain region known to be involved in inhibitory control, during successful response inhibitions relative to nonsmokers. This effect was significantly higher during nicotine abstinence relative to satiety. Smokers also exhibited lower CBF in the bilateral inferior frontal gyrus than nonsmokers. These hypoperfusions were not different between abstinence and satiety. CONCLUSIONS: These findings converge on alterations in smokers in prefrontal circuits known to be critical for inhibitory control. These effects are present, even when smokers are satiated, but the neural activity required to achieve performance equal to controls is increased when smokers are in acute abstinence. IMPLICATIONS: Our multimodal neuroimaging study gives neurobiological insights into the cognitive demands of maintaining abstinence and suggests targets for assessing the efficacy of therapeutic interventions.

Dental caries on CT in the ER population: prevalence and reporting practices.

PURPOSE: Although dental caries can be identified on CT and may be treatable, the literature provides little, if any, guidance on the responsibility of a neuroradiologist in reporting them. Untreated dental caries can impact diet and nutrition and can result in a variety of complications such as an odontogenic abscess, tooth loss, sinusitis, and dental pain, which can impact quality of life. The estimated prevalence of untreated dental caries in adults is 27%. In our experience, the prevalence of untreated dental caries in patients presenting to the Emergency Department (ED) is higher but dental caries are often unmentioned or unrecognized. We aim to determine the frequency of unreported dental caries and propose a paradigm for reporting and management. METHODS: Our research was IRB-approved and HIPPA compliant. We searched the radiology database for adult patients who underwent a CT of the facial bones while in the Emergency Department between January 1, 2015 and June 30, 2015. The examinations were reviewed by a faculty neuroradiologist for the presence of untreated dental caries. Untreated dental caries were documented and characterized by depth. Caries that were partially or completely obscured by dental amalgam artifact were excluded. The radiology reports were reviewed to evaluate reporting frequency. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) software. RESULTS: A total of 200 patients (113 male, 87 female; age 18-98 years) underwent 200 CT examinations of the facial bones. One hundred fourteen (57%) patients had at least one dental caries. When caries were present, 14.9% of radiology reports included caries in the findings section and 9.6% of the reports mentioned caries in the impression. CONCLUSIONS: The presence of dental caries should be mentioned in the radiology report. The prevalence of untreated dental caries is higher in our cohort than reported in the general population, and dental caries are underreported by neuroradiologists at our institution. A paradigm for reporting and management was created upon collaboration with faculty from the University of Vermont Dental and Oral Health practice. A visit with a dentist should be recommended within 6 months if caries are limited to the enamel, within 3 months if caries involve the dentin, and within 2 weeks if caries extend in to the pulp. Further research is necessary to determine the clinical impact of improved reporting.

Pediatric anesthesia and neurotoxicity: what the radiologist needs to know.

The use of cross-sectional imaging in the pediatric population continues to rise, particularly the use of MRI. Limiting motion artifact requires cooperative subjects who do not move during imaging, so there has been an increase in the need for pediatric sedation or anesthesia. Over the last decade, concern has increased that exposure to anesthesia might be associated with long-term cognitive deficits. In this review we report current understanding of the effects of anesthesia on the pediatric population, with special focus on long-term developmental and cognitive outcomes, and suggest how radiologists can use new technologies or imaging strategies to mitigate or minimize these potential risks.

Postconcussion symptoms are associated with cerebral cortical thickness in healthy collegiate and preparatory school ice hockey players.

OBJECTIVE: To investigate the degree to which concussion history and postconcussive symptoms are associated with cortical morphology among male hockey players. STUDY DESIGN: Male subjects (n = 29), ranging in age from 14 to 23 years (mean 17.8 years), were recruited from preparatory school and collegiate ice hockey teams and underwent neuroimaging and baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) testing. Cerebral cortical thickness was regressed against ImPACT Total Symptom Score (TSS), concussion history, as well as baseline measures of psychopathology. Reconstruction of surfaces and cortical thickness analysis were conducted with FreeSurfer (version 5.3.0). RESULTS: ImPACT TSS was inversely associated with local cortical thickness in widespread brain areas. Associations were revealed in a host of frontal as well as bilateral temporoparietal cortices. Conversely, concussion history was not associated with cortical thickness. An "Age by Concussion History" interaction was associated with thickness in the right ventrolateral and right parietal cortices. Post-hoc analysis revealed that concussed participants did not exhibit age-related cortical thinning in these regions. CONCLUSION: We have identified an association between brain structure and postconcussive symptoms among young, otherwise-healthy male athletes. Postconcussive symptoms and related reductions in cortical thickness may be tied to participation in a full-contact sport that involves frequent blows to the head.

In vivo quantitative whole-brain T1 rho MRI of multiple sclerosis.

BACKGROUND: To apply quantitative whole-brain T1 -rho (T1ρ ) and T2 imaging to the detection and quantification of brain changes resulting from multiple sclerosis (MS). METHODS: Twenty-three MS patients with clinically isolated syndrome (10) and relapsing remitting MS (13) phenotypes, compared with 24 age-matched healthy controls were imaged at 3 Tesla. An axial T1ρ -weighted three-dimensional turbo spin echo sequence with a variable flip angle and fluid suppression was used. Spin-lock times of 0, 20, 40, 60, 80, and 100 ms were used. Corresponding T2 maps were also acquired. RESULTS: Whole brain white matter (WM) T1ρ maps were elevated compared with controls (P = 0.002). WM lesion T1ρ and T2 values were highly correlated (r = 0.83), but T1ρ demonstrated 25% better contrast to noise ratio (P < 0.001). WM lesion T1ρ correlated with disease duration. Gray matter T1ρ was negatively correlated with the Expanded Disability Status Scale, r = -0.45, P = 0.03. Normal appearing gray matter and cortical gray matter lesions were negatively correlated on T1ρ , but not on T2 (rT1ρ = -0.63, pT1ρ = 0.03; rT2 = -0.17, pT2 = 0.6). CONCLUSION: T1ρ MRI demonstrates enhanced lesion contrast compared with T2 , and in some cases may provide complementary information. T1ρ may provide a useful measure of demyelinating processes in MS.

Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion.

PURPOSE: To investigate the extent of bias in a clinical study involving "pothole analysis" of diffusion-tensor imaging (DTI) data used to quantify white matter lesion load in diseases with a heterogeneous spatial distribution of pathologic findings, such as mild traumatic brain injury (TBI), and create a mathematical model of the bias. MATERIALS AND METHODS: Use of the same reference population to define normal findings and make comparisons with a patient group introduces bias, which potentially inflates reported diagnostic performance. In this institutional review board-approved prospective observational cohort study, DTI data were obtained in 20 patients admitted to the emergency department with mild TBI and in 16 control subjects. Potholes and molehills were defined as clusters of voxels with fractional anisotropy values more than 2 standard deviations below and above the mean of the corresponding voxels in the reference population, respectively. The number and volume of potholes and molehills in the two groups were compared by using a Mann-Whitney U test. RESULTS: Standard analysis showed significantly more potholes in mild TBI than in the control group (102.5 ± 34.3 vs 50.6 ± 28.9, P < .001). Repeat analysis by using leave-one-out cross-validation decreased the apparent difference in potholes between groups (mild TBI group, 102.5 ± 34.3; control group, 93.4 ± 27.2; P = .369). It was demonstrated that even with 100 subjects, this bias can decrease the voxelwise false-positive rate by more than 30% in the control group. CONCLUSION: The pothole approach to neuroimaging data may introduce bias, which can be minimized by independent training and test groups or cross-validation methods. This bias is sufficient to call into question the previously reported diagnostic performance of DTI for mild TBI.

Training the New Radiologists: Approaches for Education.

The field of Radiology is continually changing, requiring corresponding evolution in both medical student and resident training to adequately prepare the next generation of radiologists. With advancements in adult education theory and a deeper understanding of perception in imaging interpretation, expert educators are reshaping the training landscape by introducing innovative teaching methods to align with increased workload demands and emerging technologies. These include the use of peer and interdisciplinary teaching, gamification, case repositories, flipped-classroom models, social media, and drawing and comics. This publication aims to investigate these novel approaches and offer persuasive evidence supporting their incorporation into the updated Radiology curriculum.

In vivo quantification of T1ρ in lumbar spine disk spaces at 3 T using parallel transmission MRI.

OBJECTIVE: T1ρ MRI is an emerging, quantitative imaging modality that has been shown to correlate with proteoglycan content of disk material in vitro at 1.5 T. The purpose of this study is to quantify T1ρ values at all lumbar spine disk space levels at 3 T with parallel-transmission MRI in healthy adult volunteers. SUBJECTS AND METHODS: Thirty-four subjects (15 men, ages 21-60 years [mean age, 38.4 years]; and 19 women, ages 20-56 years [mean age, 36.5 years]) with no history of back pain or surgery underwent T1ρ MRI of the lumbar spine at 3 T with parallel transmission and sagittal T2-weighted imaging. Mean T1ρ values of all lumbar spine disk space levels were quantified. Linear regression analysis and Spearman rank correlation were performed on age, sex, degenerative grade (Pfirrmann scores), and T1ρ with significance set at p < 0.05 and correlations considered strong for r > 0.7 and moderate for r = 0.5-0.7. RESULTS: There was a statistically significant moderate negative correlation between T1ρ and subject age at disk space levels L1-2 through L4-5 (inclusive) (p < 0.001) and L5-S1 (p < 0.01). There was a statistically significant difference in T1ρ between all age groups sampled (p < 0.01) and a significant difference between T1ρ and Pfirrmann grades 1-3 (p < 0.01). CONCLUSION: T1ρ MRI in the lumbar spine with parallel transmission shows signifi-cant negative correlations with age at all disk space levels, which lends support to a potential role for T1ρ as a quantitative, in vivo biomarker of disk degeneration.

Cerebral Amyloid Angiopathy.

Cerebral amyloid angiopathy (CAA) is associated with deposition of amyloid proteins within the intracranial vessels. It is most frequently sporadic and risk increases with advancing age. Amyloid deposition is associated with increased risk of peripheral microhemorrhage, lobar hemorrhage, and/or repetitive subarachnoid hemorrhage. The presence of a peripherally located lobar hemorrhage on computed tomography in an elderly patient should raise concern for underlying CAA, as should multiple foci of peripheral susceptibility artifact or superficial siderosis on susceptibility-weighted imaging, the most sensitive modality for these findings. Newer PET radiotracers are also useful in detecting amyloid deposition.

Effectiveness of four different clinical fMRI paradigms for preoperative regional determination of language lateralization in patients with brain tumors.

INTRODUCTION: Blood oxygen level-dependent functional magnetic resonance imaging (fMRI) has demonstrated its capability to provide comparable results to gold standard intracarotid sodium amobarbital (Wada) testing for preoperative determination of language hemispheric dominance. However, thus far, no consensus has been established regarding which fMRI paradigms are the most effective for the determination of hemispheric language lateralization in specific categories of patients and specific regions of interest (ROIs). METHODS: Forty-one brain tumor patients who performed four different language tasks-rhyming (R), silent word generation (SWG) sentence completion, and sentence listening comprehension (LC)-for presurgical language mapping by fMRI were included in this study. A statistical threshold-independent lateralization index (LI) was calculated and compared among the paradigms in four different ROIs for language activation: functional Broca's (BA) and Wernicke's areas (WA) as well as larger anatomically defined expressive (EA) and receptive (RA) areas. RESULTS: The two expressive paradigms evaluated in this study are very good lateralizing tasks in expressive language areas; specifically, a significantly higher mean LI value was noted for SWG (0.36 ± 0.25) compared to LC (0.16 ± 0.24, p = 0.009) and for R (0.40 ± 0.22) compared to LC (0.16 ± 0.24, p = 0.001) in BA. SWG LI (0.28 ± 0.19) was higher than LC LI (0.12 ± 0.16, p = 0.01) also in EA. No significant differences in LI were found among these paradigms in WA or RA. CONCLUSIONS: SWG and R are sufficient for the determination of lateralization in expressive language areas, whereas new semantic or receptive paradigms need to be designed for an improved assessment of lateralization in receptive language areas.

Magnetic resonance diffusion tensor imaging (MRDTI) of the optic nerve and optic radiations at 3T in children with neurofibromatosis type I (NF-1).

BACKGROUND: Optic pathway glioma (OPG) is a characteristic hallmark of neurofibromatosis type I (NF-I). OBJECTIVE: To evaluate the feasibility of magnetic resonance diffusion tensor imaging (MRDTI) at 3T to detect abnormalities of the optic nerves and optic radiations in children with NF-I. MATERIALS AND METHODS: 3-T MRDTI was prospectively performed in 9 children with NF-I (7 boys, 2 girls, average age 7.8 years, range 3-17 years) and 44 controls (25 boys, 19 girls, average age 8.1 years, range 3-17 years). Fractional anisotropy (FA) and mean diffusivity were determined by region-of-interest analysis for the optic nerves and radiations. Statistical analysis compared controls to NF-I patients. RESULTS: Two NF-I patients had bilateral optic nerve gliomas, three had chiasmatic gliomas and four had unidentified neurofibromatosis objects (UNOs) along the optic nerve pathways. All NF-I patients had statistically significant decreases in FA and elevations in mean diffusivity in the optic nerves and radiations compared to age-matched controls. CONCLUSION: MRDTI can evaluate the optic pathways in children with NF-I. Statistically significant abnormalities were detected in the diffusion tensor metrics of the optic nerves and radiations in children with NF-I compared to age-matched controls.

Case Report: Yellow Fever Vaccine-Associated Neurotropic Disease and Associated MRI, EEG, and CSF Findings.

Yellow fever vaccine-associated neurotropic disease (YEL-AND) is a rare and serious complication following vaccination with the 17D live attenuated yellow fever vaccine. Cases of YEL-AND have presented as acute inflammatory demyelinating polyneuropathy, acute disseminated encephalomyelitis, and meningoencephalitis. To date, intracranial imaging of the progression and resolution of this disease has been minimally depicted in the literature. We present the case of a 67-year-old woman who developed YEL-AND following vaccination. Her diagnosis was complicated by imaging findings consistent with variant Creutzfeldt Jakob Disease. Her clinical history and the progression of her intracranial imaging is discussed in this case report.

An oropharyngeal device for airway management of conscious and semiconscious patients: A randomized clinical trial.

OBJECTIVE: No oropharyngeal devices exist for use in conscious and semiconscious trauma patients during emergency evacuation, transport, or resuscitation. We aimed to test the hypotheses that the ManMaxAirway (MMA) is better tolerated than the standard Guedel-style device in awake volunteers and that it produces a jaw thrust and improves air flow. METHODS: This was a randomized cross-over study of healthy volunteers with either the MMA or standard device. The primary outcome of tolerability was defined as maintaining the device in place for 60 seconds. Secondary outcomes included respiratory system function and jaw thrust. Resistance to airflow through the device lumen was measured in situ and when placed in subjects in the pulmonary laboratory alone. Jaw thrust was quantified as displacement between the mandibular condyle and condylar fossa apex relative to baseline visualized with magnetic resonance imaging (MRI). RESULTS: We enrolled 19 subjects. Of these, a convenience sample of 5 individuals was selected for MRI; the remaining individuals (n = 14) were randomized for the cross-over study. All 14 subjects were able to maintain the MMA for 60 seconds compared with 2/14 (14%) with the standard device (odds ratio, 145; 95% confidence interval, 6.3-3314). Subjects reported that the experimental device was more comfortable and its placement did not trigger the gag reflex. Airway resistance produced by the MMA in an oscillatory flow model was nearly an order of magnitude lower than that of the standard device (experimental vs standard, 8 Hz-0.092 vs 0.786 cmH20·s/L; 15 Hz-0.193 vs 1.321 cmH20·s/L). Rapid induction of the gag reflex precluded further measurements with the standard device. Forced oscillation pulmonary testing in conscious volunteers with and without the MMA demonstrated that the device decreased respiratory system resistance to airflow and reduced respiratory elastance (31% ± 8% and 44% ± 13.4%, respectively; P < 0.05). MRIs of the subjects (n = 5) with the MMA in place showed a significant jaw thrust compared with baseline (7 ± 1 mm). CONCLUSIONS: The MMA proved well tolerated in conscious subjects, resulting in an opening of the anatomic airway and a decreased resistance to airflow.

Mechanisms of targeted therapy resistance in a pediatric glioma driven by ETV6-NTRK3 fusion.

Chromosomal rearrangements of the NTRK genes generate kinase fusions that are targetable oncogenic drivers in diverse adult and pediatric malignancies. Despite robust clinical response to targeted NTRK inhibition, the emergence of therapeutic resistance poses a formidable clinical challenge. Here we report the characterization of an ETV6-NTRK3 fusion-driven pediatric glioma that progressed through NTRK-targeted treatments with entrectinib and selitrectinib. Genetic analysis of multifocal recurrent/resistant lesions identified a previously uncharacterized NTRK3 p.G623A and a known p.G623E resistance mutation, in addition to other alterations of potential pathogenic impact. Functional studies using heterologous reconstitution model systems and patient-derived tumor cell lines establish that NTRK3G623A and NTRK3G623E mutated kinases exhibit reduced sensitivity to entrectinib and selitrectinib, as well as other NTRK inhibitors tested herein. In summary, this genetic analysis of multifocal recurrent/resistant glioma driven by ETV6-NTRK3 fusion captured a cross section of resistance-associated alterations that, based on in vitro analysis, likely contributed to resistance to targeted therapy and disease progression.

Diffusion tensor imaging of the pediatric optic nerve: intrinsic and extrinsic pathology compared to normal controls.

PURPOSE: To establish normative magnetic resonance diffusion tensor imaging (MRDTI) data in the pediatric optic nerve and compare to pathologic conditions both intrinsic and extrinsic to the anterior optic nerve pathway. MATERIALS AND METHODS: A retrospective analysis of MRDTI at 3.0T in children ages 0-18 with both normal imaging studies and with pathologic conditions either arising from the optic nerves or exerting mass effect on the anterior optic pathways was performed. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained within the posterior part of the intraorbital optic nerves. Statistical analysis compared normal controls to optic pathway lesions. RESULTS: Lesions intrinsic to the optic nerve including septo-optic dysplasia and optic nerve glioma demonstrated statistically significant reductions in FA and increases in ADC values. There was no statistically significant difference in FA or mean diffusivity between the normal controls and patients with lesions extrinsic to the optic nerve but exerting mass effect on the visual pathway. CONCLUSION: MRDTI is a feasible technique for evaluating the optic nerves in pediatric patients. It may play a role in presurgical planning by demonstrating integrity of the visual pathway in patients with resectable lesions, allowing for minimization of morbidity associated with vision loss.

Magnetic resonance diffusion tensor imaging (MRDTI) and tractography in children with septo-optic dysplasia.

BACKGROUND: Septo-optic dysplasia (SOD) refers to a heterogeneous group of midline brain developmental anomalies, with optic nerve hypoplasia (ONH) being one of the morphologic correlates of the condition. Traditionally, ONH has been diagnosed on fundoscopic exam. Conventional MRI is used in cases of suspected ONH to identify associated brain abnormalities and to compare findings to the fundoscopic exam. Advances in magnetic resonance diffusion tensor imaging (MRDTI) permit in vivo, noninvasive, quantitative characterization of the entire visual pathway at 3.0 T. OBJECTIVE: To investigate the feasibility of MRDTI at 3.0 T in children with SOD to evaluate the entire visual pathway. MATERIALS AND METHODS: MRDTI at 3T was performed in two children with SOD and seven age-matched controls. Manual region-of-interest analysis was used to evaluate the tensor metrics of the optic nerves. Deterministic tractography was used to evaluate the tensor metrics of the optic radiations. RESULTS: The SOD patients demonstrated a significant decrease in anisotropy and increase in mean diffusivity of the optic nerves and radiations compared to the control subjects. CONCLUSION: This study demonstrates the feasibility of MRDTI to evaluate the entire visual pathway in children, and it demonstrates pre- and post-chiasmatic diffusion tensor abnormalities in SOD patients.

The misinterpretation rates of radiology residents on emergent neuroradiology magnetic resonance (MR) angiogram studies: correlation with level of residency training.

The purpose of this study was to determine the discrepancy rates of radiology residents interpreting emergent neck and Circle of Willis magnetic resonance angiography (MRA) studies and to detect any adverse clinical outcomes. Three hundred seventeen MRA studies given preliminary reading by radiology residents were retrospectively reviewed over a 2-year period. Discrepancies were classified as either false negatives (failure to diagnose abnormalities) or false positives (misinterpreting normal scans as abnormal). The overall discrepancy rate was 12.1% for Circle of Willis MRA and 7.9% for neck MRA. Fourth-year residents had the lowest discrepancy rates (7.7%), but this was not statistically significant. The most common misses were stenosis greater than 70% (n = 9) and aneurysm (n = 12). No adverse clinical outcome was detected mainly due to rapid turnaround time for final reporting.

Correlation Between Radiology ACGME Case Logs Values and ABR Core Exam Pass Rate.

RATIONALE AND OBJECTIVES: There is discordance between the American Board of Radiology (ABR) and many radiology trainees with respect to the most appropriate means to prepare for the ABR Core Examination. Whereas the ABR suggests that participation in routine clinical examination interpretation best prepares a trainee for the practical material of the test, residents, and many program directors feel that time away from clinical service for study and review courses are necessary. This study examines the relationship between studies interpreted in the first three years of residency as reported in the Accreditation Council for Graduate Medical Education case logs and performance of first-time test takers on the ABR Core Examination. MATERIALS AND METHODS: Accreditation Council for Graduate Medical Education case log data was anonymized for a single year cohort of residents in all accredited radiology residencies. This was then provided to the ABR and matched with performance on the Core Examination. A random effects logistic regression model was used to evaluate for a relationship between the number of examinations read and the pass/fail status of the Core Exam. RESULTS: Modeling using a linear and a quadratic term yields a significant relationship between case log values and Core Exam performance. There is a positive correlation until an inflection point of approximately 11,000 examinations, at which point a negative correlation develops. CONCLUSION: The data supports that active engagement in clinical duties is associated with better performance on the ABR Core Examination, with the caveat that there appears to be a point at which service outweighs educational value. Beyond this, performance on the examination declines.