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Year : 2015  |  Volume : 63  |  Issue : 4  |  Page : 597--603

A summary of some of the recently published seminal papers in Neuroscience

K Sridhar1, Anant Mehrotra2,  
1 Director, Institute of Neurosciences and Spinal Disorders, Global Health City, Perumbakkam, Chennai, Tamil Nadu, India
2 Assistant Professor of Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Correspondence Address:
K Sridhar
Director, Institute of Neurosciences and Spinal Disorders, Global Health City, Perumbakkam, Chennai - 600 100, Tamil Nadu

How to cite this article:
Sridhar K, Mehrotra A. A summary of some of the recently published seminal papers in Neuroscience.Neurol India 2015;63:597-603

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Sridhar K, Mehrotra A. A summary of some of the recently published seminal papers in Neuroscience. Neurol India [serial online] 2015 [cited 2020 Oct 26 ];63:597-603
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 Herman ST et alConsensus statement on continuous EEG in critically ill adults and children, part I: Indications. J Clin Neurophysiol 2015;32:87-95.

Electroencephalogram (EEG) measures the brain's electrical activity, can be recorded continuously at the bedside, has good spatial and excellent temporal resolution, and is sensitive to changes in both brain structure and function. In the last decade, technical advances have improved the efficiency of continuous EEG (CEEG) recording and remote review, leading to a greater than 4-fold increase in the number of CEEGs performed in intensive care units (ICUs). Critical care CEEG (CCEEG) refers to the simultaneous recording of EEG and clinical behavior by video over extended time periods in critically ill patients at risk for secondary brain injury and neurologic deterioration. CCEEG is usually performed in an ICU setting. The goal of CCEEG is to identify changes in brain function, such as nonconvulsive seizures (NCS) or ischemia, which may not be evident by neurological examination alone, to facilitate early identification and management of these abnormalities. This consensus statement describes the most common indications for CCEEG in adults and children.

The indications for CCEEG are: (1) Diagnosis of NCS, nonconvulsive status epilepticus, and other paroxysmal events; (2) Assessment of efficacy of therapy for seizures and status epilepticus; (3) Identification of cerebral ischemia; (4) Monitoring of sedation and high-dose suppressive therapy; and (5) Assessment of severity of encephalopathy and its prognostication.

 Veeravagu A, et al Improved capture of adverse events after spinal surgery procedures with a longitudinal administrative database. J Neurosurg Spine 2015 Jun 12:1-9. PMID: 26068273.

The authors conducted a retrospective analysis of longitudinal administrative data from a sample of approximately 189,000 patients. Overall and procedure-specific complication rates at 5 time points ranging from the immediate postoperative (index) to 30 days postoperative period were computed. The results indicated that the frequency of individual complication types increased at different rates. The overall complication rate including all spine surgeries was 13.6% at the index time point and increased to 22.8% at 30 days postoperatively. When specific surgical procedures were considered, the 30-day complication rates ranged from 8.6% in single-level anterior cervical fusions to 27.3% in multilevel combined anterior and posterior lumbar spine fusions. This study demonstrates the usefulness of a longitudinal administrative database in assessing the postoperative complication rates after spine surgery.

 Schroeder GD, et al. Axial interbody arthrodesis of the L5-S1 segment: A systematic review of the literature. J Neurosurg Spine 2015 Jun 12:1-6. PMID: 26068275

The authors conducted a systematic search of MEDLINE for the literature published between January 1, 2000, and August 17, 2014. All peer-reviewed articles related to the fusion rate of the L5-S1 segment and the safety profile of an axial interbody arthrodesis were evaluated. The objective of this study was to determine the fusion rate and safety profile of an axial interbody arthrodesis of the L5-S1 motion segment. Seventy-four articles were identified, but only 15 (13 case series and 2 retrospective cohort studies) met the study inclusion criteria. The authors concluded that an axial interbody fusion performed at the lumbosacral junction is associated with a high fusion rate (93.15%) and an acceptable complication rate (12.90%). However, these results are based mainly on retrospective case series by authors with a conflict of interest. The limited prospective data available indicate that the actual fusion rate may be lower and the complication rate may be higher than the currently reported ones.

 Samii M, et al. Prognostic significance of peritumoral edema in patients with vestibular schwannomas. Neurosurgery 2015;77:81-6.

The authors systematically evaluated the significance of peritumoral edema (PTE) in vestibular schwannomas (VS). A retrospective study of 30 patients with PTE was conducted. The preoperative patient data and intraoperative tumor features (presence of tumor pseudocapsule, vascularity, degree of adhesion/invasion of the arachnoid) were noted. The outcome measures were completeness of removal, neurological outcome, and complication rate. These parameters in patients with PTE (Group A) were correlated to those in matched series without edema (Group B). The authors concluded that PTE in VS does not correlate with the degree of tumor adhesion and the presence of an arachnoid dissection plane. The tumors with PTE were hypervascular and the patients suffered an early worse facial function compared with the non-PTE patients.

 Spetzler RF, et al. The Barrow Ruptured Aneurysm Trial: 6-year results. J Neurosurg 2015 Jun 26:1-9. PMID: 26115467.

The authors report the 6-year results of the Barrow Ruptured Aneurysm Trial (BRAT). This ongoing randomized trial, with the final goal of a 10-year follow-up, compares the safety and efficacy of surgical clip occlusion and endovascular coil embolization in patients presenting with subarachnoid hemorrhage (SAH) from a ruptured aneurysm. In total, 500 patients with SAH met the entry criteria and were enrolled in the study. Of these patients, 471 were randomly assigned to the treatments: 238 to surgical clipping and 233 to endovascular coiling. Six years after randomization, 336 (82%) of 408 patients who had been treated were available for examination. On the basis of a modified Rankin scale (mRS) score of >2, and similar to the results at the 3-year follow-up, no significant difference in outcomes (P = 0.24) was detected between the two treatment groups. Complete aneurysm obliteration at 6 years was achieved in 96% (111/116) of the clipping group and in 48% (23/48) of the coiling group (P < 0.0001). When aneurysm location was considered, the 6-year results continued to match the previously reported results, with no difference in outcome for anterior circulation aneurysms at most time points. Of the anterior circulation aneurysms assigned to the coiling treatment, 42% (70/168) were crossed over to the clipping treatment. The outcomes for posterior circulation aneurysms continued to favor coiling.

The authors concluded that aneurysm obliteration rates in BRAT were significantly lower and retreatment rates significantly higher in the patients undergoing coiling than in those undergoing clipping. However, despite the fact that retreatment rates were higher after coiling, no recurrent hemorrhages were known to have occurred in patients undergoing coiling in BRAT who were followed up for 6 years.

 Bayston R, et al. Does release of antimicrobial agents from impregnated external ventricular drainage catheters affect the diagnosis ofventriculitis? J Neurosurg 2015 Jun 12:1-7. PMID:26067618.

Recently, concern has arisen over the effect of released antimicrobial agents from antibiotic-impregnated external ventricular drainage (EVD) catheters on the reliability of cerebrospinal fluid (CSF) culture for establishing the diagnosis of ventriculitis. The authors designed a laboratory study to investigate this possibility and to determine whether there was also a risk of loss of bacterial viability when CSF samples were delayed in transport to the laboratory.

The authors found that while there were differences between the tested catheters, only samples taken on day 1 showed a significant reduction in the numbers of viable bacteria after passing through the catheters. The results indicate that drugs released from these antimicrobial catheters are unlikely to affect the diagnosis of ventriculitis, as sampling for this purpose is not usually conducted in the first 24 h of EVD.

 Nerland US, et al. Minimally invasive decompression versus open laminectomy for central stenosis of the lumbar spine: Pragmatic comparative effectiveness study. BMJ 2015 Apr 1;350:h1603. Doi:10.1136/bmj.h1603. PMID: 25833966.

The authors tested the equivalence for clinical effectiveness between microdecompression and laminectomy in patients with central lumbar spinal stenosis in a prospective multicenter trial. Eight hundred and eighty-five patients were selected over 34 centers in this observational study.

The authors found that at 1 year, the effectiveness of microdecompression is equivalent to laminectomy in the surgical treatment of central stenosis of the lumbar spine. Favorable outcomes were observed at 1 year in both treatment groups.

 Shah S, et al. Screening with MRI for accurate and rapid stroke treatment: SMART. Neurology 2015;84:2438-44.

The objective of this study was to demonstrate the feasibility of timely multimodal magnetic resonance imaging (MRI) screening before thrombolysis in acute stroke patients.

There were 157 patients treated with intravenous tissue plasminogen activator (IV tPA) for acute ischemic stroke (AIS) during 2012-2013, of whom 135 (86%) were screened with MRI. It is feasible and practical to consistently and rapidly deliver IV tPA to AIS patients within national benchmark times using MRI as the routine screening modality.

 Lau D et al. Two-level corpectomy versus three-level discectomy for cervical spondylotic myelopathy: A comparison of perioperative, radiographic, and clinical outcomes. J Neurosurg Spine 2015 Jun 19:1-10. PMID: 26091438.

The authors examine whether anterior cervical corpectomy and fusion (ACCF) and anterior cervical discectomy and fusion (ACDF) offer equivalent outcomes for multilevel cervical spondylotic myelopathy. In this study, the authors compared perioperative, radiographic, and clinical outcomes between 2-level ACCF and 3-level ACDF. Twenty patients underwent 2-level ACCF, and 35 patients underwent 3-level ACDF during a 6-year period. The authors concluded that perioperative complication rates were similar in the two groups when patients underwent anterior decompression alone. Both groups obtained similar postoperative cervical lordosis, operative adjacent segment disease rates, radiographic pseudarthrosis rates, neurological improvement, and pain relief.

 Wang JY et al. Serial imaging surveillance for patients with a history of intracranial aneurysm: Risk of de novo aneurysm formation. Neurosurgery 2015;77:32-43.

The authors have retrospectively studied de novo intracranial aneurysms (DNIA) in 26 patients out of 2153 cases of intracranial aneurysms. Out of the 2153 cases, 185 patients were under surveillance among which 9 (4.9%) cases developed DNIA with the overall risk of DNIA detection being 1.14% per person-year of follow-up (95% confidence interval [CI]: 0.6-2.2%). The authors found that imaging follow-up significantly improved DNIA detection when compared with lack-of-imaging follow-up (4.9% vs. 0.86%; P < 0.001), however the size of the DNIA was less in the surveillance group when compared with the without-imaging follow-up group (with surveillance: 3.8 ± 1.8 mm, without: 7.0 ± 4.4 mm [mean ± standard deviation]; P = 0.026). The association of smoking with DNIAs was not significant but was close to significance. The authors concluded that the low detection rates of DNIA (1.14% per-person year) and relatively smaller aneurysms detected, does not justify routine surveillance of DNIA in all patients with a history of intracranial aneurysms. However, surveillance might be of help in cases who continue to smoke.

 Catenoix H, et al. Seizures outcome after stereoelectroencephalography-guided thermocoagulations in malformations of cortical development poorly accessible to surgical resection. Neurosurgery 2015;77:9-15.

The authors have studied the need and benefit of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RFTC) - 120 mA current at 50 V for 10-30 s - in cases of malformation of cortical development (MCD) in surgically difficult areas/eloquent areas of brain in patients who have drug-resistant partial epilepsy. The authors performed RFTC in 10 male and 4 female patients and on an average 25.8 ± 17.5 thermolesions were done during each procedure. On long-term follow-up (median follow-up of 41.7 months), 64% of the cases had >50% reduction in the seizure frequency with 6 patients (43%) having seizure freedom. The authors found that in 87.5% of cases in whom a focal low-voltage fast activity was detected at seizure onset on SEEG were either responders or seizure-free. All those patients, in whom spontaneous seizure was reproduced by electric stimulation, also responded to the treatment. The authors concluded that there was a good benefit-risk ratio of SEEG-guided procedures for patients with MCD in surgically difficult areas. Two factors appear to have a predictive value of a favorable outcome, namely focal low-voltage fast activity and lowered epileptogenic threshold in the coagulated area.

 Rangel-Castilla L, et al. The 6 thalamic regions: Surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes. J Neurosurg 2015 May 29:1-10. PMID: 26024002.

The authors have suggested a surgical classification of the thalamus based on which the authors used a corresponding surgical approach for thalamic cavernomas. The authors have divided the thalamus into six regions namely Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). Depending on the region in which the cavernoma was located, the surgical approach was chosen. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricular for Region 5; and supracerebellar-infratentorial for Region 6. Among the 46 cases of thalamic cavernomas, Region 3 was the most common (n = 17) followed by Region 2 (n = 9) and Region 3 (n = 8). Region 4 was the least common (n = 3) followed closely by Region 5 (n = 4) and Region 1 (n = 5). Two cases had to undergo a second-stage surgery and in all the other cases, complete excision was done. At a mean follow-up of 1.7 years (range: 6 months to 9 years), 40 patients (87%) had an excellent or good outcome (mRS scores 0-2) and in the remaining 6 cases, the outcome was poor (mRS scores 3-4). When compared to the preoperative status, 42 patients were either unchanged or improved, and 4 were worse. The authors conclude that conceptually dividing thalamus into six regions helps one in deciding the best possible surgical outcome.

 Stephan BC, et al. Usefulness of data from magnetic resonance imaging to improve prediction of dementia: Population based cohort study. BMJ 2015 Jun 22;350:h2863. Doi:10.1136/bmj.h2863.

The authors have conducted a population-based cohort study of individuals aged ≥65 years to determine whether the addition of MRI (brain) data to a model incorporating the conventional risk variables can improve prediction of dementia over a 10-year follow-up. A total of 1721 people without dementia underwent MRI brain and were followed up for 10 years. One hundred and nineteen cases developed dementia, out of which 84 were diagnosed with Alzheimer's disease. When compared with the conventional risk model (which includes age, sex, education, cognition, physical function, lifestyle [smoking, alcohol use], health [cardiovascular disease, diabetes, systolic blood pressure], and the apolipoprotein genotype), the MRI data model (hippocampal volume, brain volume, and white matter [WM] volume) did not show any significant difference in predicting dementia. However, when MRI data were combined with the conventional risk model, this leads to a significant improvement in reclassification measured by using the integrated discrimination improvement index (P = 0.03 and 0.04) and showed an increased net benefit in the decision curve analysis. When the outcome was restricted to Alzheimer's disease, the results were similar. The authors concluded that the MRI data did not significantly improve discrimination performance in the prediction of all causes of dementia. However, it did help in the clinical management by improving their reclassification and prognostication.

 Low PA, et al. Natural history of multiple system atrophy in the USA: A prospective cohort study. Lancet Neurol 2015;14:710-9.

The authors report a prospective natural history study of multiple system atrophy (MSA) which is a rare, fatal neurodegenerative disorder. The study was multicentric with recruitment of cases of probable MSA (n = 175, with a mean age of 63.4 years) of both the Parkinsonism variant (MSA-P) and the cerebellar ataxia variant (MSA-C) from across 12 centers in the USA specializing in movement or autonomic disorders. These patients were followed up every 6 months for 5 years and were assessed with Unified Multiple System Atrophy Rating Scale part I (UMSARS I; a functional score of symptoms and ability to undertake activities of daily living), UMSARS II (neurological motor evaluation), and the Composite Autonomic Symptoms Scale-select (a measure of autonomic symptoms and autonomic functional status). The median survival from symptom onset and enrollment was 9.8 and 1.8 years, respectively. Patients who had severe symptomatic autonomic failure at diagnosis (n = 62, with a median survival of 8 years) had a worse prognosis than those patients who did not have these symptoms (n = 113, with a median survival of 10.3 years). There was no significant difference between the baseline symptoms and the functional status of MSA-P and MSA-C. The authors concluded that the natural history of MSA-C and MSA-P are similar and the presence of severe symptomatic autonomic failure at diagnosis is associated with a worse prognosis.

 ProGas Study Group. Gastrostomy in patients with amyotrophic lateral sclerosis (ProGas): A prospective cohort study. Lancet Neurol 2015;14:702-9.

The study intends to compare various methods of gastrostomy in cases of amyotrophic lateral sclerosis (ALS). The authors conducted a longitudinal, prospective Cohort study (ProGas) in which patients with a diagnosis of definite, probable, laboratory-supported, or possible ALS were included from 24 centers across UK. Among the 345 patients of ALS, 330 underwent gastrostomy. Percutaneous endoscopic gastrostomy (PEG) was performed in 49% of the cases (n = 163), radiologically inserted gastrostomy (RIG) was performed in 37% of patients (n = 121), 13% (n = 43) underwent per-oral image-guided gastrostomy (POG), and 1% (n = 3) underwent surgical gastrostomy. Twelve patients (4%, 95% CI: 2.1-6.2) died within the first 30 days after a gastrostomy. Among these 12, 5 had PEG, 4 had RIG, and 3 had POG. Fourteen repeat attempts at gastrostomy were made and 21 (including these 14) of the total 344 gastrostomies failed. Among these 21, in 11 PEG, in 7 RIG, and in 3 POG were performed. All the three methods of gastrostomies appeared to be having equivalent results in relation to survival and procedural complications. This study will help in the nutritional management of patients with ALS.

 Adam O,et al. Clinical and imaging assessment of acute combat mild traumatic brain injury in Afghanistan. Neurology 2015 Jun 24. pii: 10.1212/WNL.0000000000001758. PMID: 26109715.

This prospective observational study included 95 US military service members who sustained a mild traumatic brain injury (mTBI). The subjects were enrolled within 7 days of their injury sustained in Afghanistan. It also recruited 101 healthy controls (HCs). All cases underwent assessments using the Rivermead Postconcussion Symptoms Questionnaire, Posttraumatic Stress Disorder Checklist Military, Beck Depression Inventory, Balance Error Scoring System, Automated Neuropsychological Assessment Metrics (ANAM), and the conventional MRI including the diffusion tensor imaging (DTI) sequence. Based on these tools, the authors found that people with mTBI had a significantly greater somatic, behavioral, cognitive, and performance-based impairment when compared to the control population. The simple reaction time studied by ANAM was the most significantly affected parameter. Fractional anisotropy was significantly reduced in the right superior longitudinal fasciculus in the mTBI group as compared to the control group. However, in these cases, the conventional MRI did not detect any abnormality. The various scores used correlated with time to return to duty. The authors concluded that in cases of acute blast-related mTBI, somatic, behavioral, and cognitive symptoms as well as performance deficits are significantly more. DTI is more sensitive in detecting white matter integrity in blast-related mTBI than the conventional MRI sequences.

 Daams M,et al. Unraveling the neuroimaging predictors for motor dysfunction in long-standing multiple sclerosis. Neurology 2015 Jun 26. pii: 10.1212/WNL.0000000000001756. [Epub ahead of print] PMID: 26115736.

By this cross-sectional study, the authors intended to find the neuroimaging predictors for motor dysfunction in a cohort of patients who suffered from long-standing multiple sclerosis (MS). The authors compared conventional and quantitative neuroimaging parameters focusing on the corticospinal tract. The motor disability was also assessed using the Expanded Disability Status Scale (EDSS), 9-Hole PEG Test, Timed 25-Foot Walk Test, and Multiple Sclerosis Walking Scale. One hundred and ninety-five patients with MS and 54 healthy controls were enrolled in the study. The average duration of the disease was 19.98 (±6.99) years, with a median EDSS score of 4 (range: 1.0-8.0). The EDSS was associated with multiple infratentorial and cervical cord lesions, a lesion volume in the corticospinal tract, and a mean upper cervical cord area; the Timed 25-Foot Walk test score with a number of infratentorial lesions and cerebellar volume; the 9-Hole PEG Test score with a number of infratentorial lesions and thickness of the cortex connected to the corticospinal tract; Multiple Sclerosis Walking Scale with a number of infratentorial and cervical lesions, thickness of the cortex connected to the corticospinal tract, and a mean upper cervical cord area. The authors concluded that motor involvement in MS is a complex phenomenon and cannot be ascribed to one imaging finding. On the contrary, it occurs because of a multi-centric infratentorial and spinal cord damage along with the involvement of the corticospinal tract.

 Johnen A, et al. Apraxia profile differentiates behavioral variant frontotemporal from Alzheimer's dementia in mild disease stages. J Neurol Neurosurg Psychiatry 2015;86:809-15.

The differentiation between the behavior variant of frontotemporal dementia (bvFTD) and Alzheimer's dementia (AD) in the early stages of the disease is difficult. Apraxia is considered to be a part of the symptom feature of AD but not of the bvFTD. The authors compared composite apraxia scores between patients suffering from AD and bvFTD as well as healthy controls (HC). Twenty patients in each group were included. The composite scores of apraxia had a high diagnostic accuracy for detecting mild stages of both AD and bvFTD when compared to HC. Limb apraxis was present in both AD and bvFTD (especially impairments in imitation of hand and finger postures and pantomine of object use). Apart from these, patients with bvFTD had a unique set of deficits for imitating facial postures. The authors concluded that praxias should be utilized more in the early diagnosis of milder forms of AD and bvFTD. Analysis of individual apraxias facilitates differentiation between early AD and bvFTD.

 Kato S,et al. META: An MRI-based scoring system differentiating metastatic from osteoporotic vertebral fractures. Spine J 2015;15:1563-70.

MRI may be useful in differentiating osteoporotic vertebral fractures (OVFs) from metastatic vertebral fractures (MVFs). However, at present, no single, unequivocal differentiating feature is defined. The authors, therefore, examined the efficacy of a scoring system based on MRI findings to differentiate OVFs from MVFs. The study was a retrospective, single-center observational study which included 100 cases of OVFs and 100 cases of MVFs involving the thoracolumbar region. The MRI was obtained within 60 days from the suspected time of the fracture. The sensitivity and specificity of seven MRI findings of these fractures were analyzed. Low-to-moderate sensitivity and a high specificity were seen in all the findings. A simpler scoring system (MRI Evaluation Totalizing Assessment) was created that helped to differentiate the two entities with a high degree of accuracy. The authors concluded that this scoring system could be helpful in differentiating OVFs from MVFs.

 Agosta F,et al. Hereditary spastic paraplegia: Beyond clinical phenotypes toward a unified pattern of central nervous system damage. Radiology 2015;276:207-18.

The authors have studied the MRI findings in cases of hereditary spastic paraplegias (HSPs). They specifically looked for brain gray matter regional volumes and white matter microstructural abnormalities and spinal cord atrophy in patients of both pure HSPs and complicated HSPs. The authors also correlated clinical and cognitive features of patients of HSP, with MRI findings suggestive of brain and cervical cord damage. Twenty genetically defined cases of HSPs and 24 cases of HSPs without a genetic diagnosis, along with 19 control healthy subjects, were included in the study. They underwent clinical, neuropsychological, and advanced MRI evaluations. Findings of gray matter atrophy and white matter microstructural damage which were found on structural and diffusion tensor imaging were compared between the groups. On clinical evaluation, the authors found that sensory disturbances and verbal and spatial memory deficits were present not only in complicated HSPs, but were also seen in pure HSPs. The authors also found that irrespective of the clinical features, MRI findings demonstrated similar involvement of the motor, association, and cerebellar WM pathways and the cervical cord. The degree of spasticity and cognitive impairment correlated with the severity of WM damage in both pure and complicated HSPs. The authors conclude that these findings support the emerging evidence that a common neurodegenerative pathway is shared by these different neurological disorders.

 Agosta F,et al. Differentiation between subtypes of primary progressive aphasia by using cortical thickness and diffusion-tensor MR imaging measures. Radiology 2015;276:219-27.

The authors have tested the cortical thickness and WM damage measurements on MRI to distinguish between the variants of primary progressive aphasia (PPA) that are nonfluent and/or agrammatic (NFVPPA) and semantic (SVPPA). Thirteen cases each of NFVPPA and SVPPA and 23 HCs underwent T1-weighted and diffusion-tensor (DT) MRIs. MR indices for long-associative and interhemispheric white matter (WM) tracts and cortical thickness were obtained. The authors analyzed the imaging features which were associated with each of the clinical syndromes and also performed an individual patient classification. Diffusivity abnormalities of the left inferior longitudinal and uncinate fasciculi, and cortical thickness measures of the left temporal pole and inferior frontal gyrus, were the best imaging markers to differentiate the two variants of PPA. A combined gray matter and WM model appears to be more robust than a single MR modality.

 Hart BL, et al. Armies of pestilence: CNS infections as potential weapons of mass destruction. AJNR Am J Neuroradiol 2015;36:1018-25.

The authors have reviewed the infectious agents which have central nervous system (CNS) manifestations with respect to their utility for biowarfare. More commonly, induction of respiratory diseases has been used for biowarfare but certain CNS infections may also be used as weapons of mass destruction. Certain viruses are known to cause encephalitis and can spread with relative ease in the aerosol form and have the potential to be used for biowarfare. CNS manifestations in anthrax, brucellosis, plaque, Q fever, and diseases caused by other bacteria can also be used for the same purpose.

 Pires P,et al. White matter alterations in the brains of patients with active, remitted, and cured Cushing syndrome: A DTI study. AJNR Am J Neuroradiol 2015;36:1043-8.

Cushing's syndrome occurs due to prolonged exposure of elevated glucocorticoids which in turn might result in changes in the white matter (WM) microstructure. The authors have studied the WM changes as detected in DTI in patients of Cushing's syndrome. Thirty five patients of Cushing's syndrome and 35 healthy controls (HC) were included in the study and underwent DTI for fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity (general linear model, family-wise error, and threshold-free cluster enhancement corrections, P < 0.05). The WM changes were evaluated by dividing the subjects into four groups, namely active Cushing's syndrome (n = 8), Cushing's syndrome with medication remitted cortisol (n = 7), surgically cured (n = 20), and HCs (n = 35). Twenty-four hour urinary free cortisol level and disease duration were also correlated with DTI values. Reduced fractional anisotropy as well as increased mean diffusivity, axial diffusivity, and radial diffusivity values (P < 0.05) were more commonly seen in patients of Cushing's syndrome than the healthy counterparts. There was no significant difference in imaging changes between the active and cured Cushing's syndrome group. The 24-h urinary free cortisol level and disease duration did not have any significant correlation with the DTI maps. The authors concluded that there are diffuse WM changes (indicating loss of WM integrity and demyelination) in patients of Cushing's syndrome and once these changes occur, they tend to persist after remission/cure.

 Wanamaker CP, et al. Qualitative and quantitative analyses of MR imaging findings in patients with middle cerebral artery stroke implanted with mesenchymal stem cells. AJNR Am J Neuroradiol 2015;36:1063-8.

The authors have retrospectively analyzed MRI of 5 patients who had received mesenchymal stem-cell implantation for middle cerebral artery (MCA) infarct. The MRI was available in the immediate postoperative phase and at 1-year follow-up. The MRIs were evaluated for volume changes between the two time points and this was compared with those in healthy and age- and sex-matched controls with chronic, stable MCA infarcts. Images were also evaluated for postimplantation complications. At the implantation site, there was susceptibility signal loss and enhancement. On volumetric analysis, there was a trend to less overall volume loss (P = 0.09) in cases with mesenchymal stem-cell implantation compared to age- and sex-matched controls with chronic stable MCA infarcts. There was a significantly greater growth-to-loss ratio in the infarcted regions (1.30 and 0.78, respectively, P = 0.02). Correlation between the growth-to-loss ratio and physical examination was seen. The results were not significant but values close to significance (r = 0.856, P = 0.06) were achieved. Also, there was no tumor, teratoma, or heterotopia identified in the postoperative period in these patients.

 Eckel-Passow JE,et al. Glioma groups based on 1p/19q, IDH, and TERT promoter mutations in tumors. N Engl J Med 2015;372:2499-508.

Based on three molecular markers, namely mutations in the TERT promoter, mutations in isocitrate dehydrogenase (IDH), and codeletion of chromosome arms 1p and 19q (1p/19q codeletion), the authors have divided gliomas into five groups. The authors compared these groups to evaluate whether tumors had similar clinical variables, acquired somatic alterations, and germline variants. The authors studied 1087 gliomas and used 11,590 controls for the study. Of 615 Grade II and III gliomas, all three mutations were seen in 29% of the cases (triple positive), 5% had TERT and IDH mutations, and 45% had only IDH mutations. Triple-negative was seen in 7%, only TERT mutations were seen in 10%, and other combinations were seen in 5% of cases. On the contrary, only 1% were triple-positive among 472 cases of Grade IV gliomas, 2% had TERT and IDH mutations, and 7% had only IDH mutations. Majority of Grade IV gliomas (74%) had only TERT mutations and 17% were triple-negative. The lowest mean age at diagnosis was seen in cases that only had IDH mutations, and the highest mean age was seen in cases that had TERT only mutation gliomas. There was an independent association between molecular groups and overall survival among patients with Grade II and III gliomas but not with Grade IV gliomas. The authors concluded that the various groups had different ages of onset, overall survival, and associations with germline mutations which might indicate that there was the presence of distinct oncogenetic mechanisms.