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Background Tandem occlusion (TO) describes not only occlusion of the middle cerebral artery but a contemporaneous occlusion of the cervical internal carotid artery. There is a paucity of data over whether mechanical thrombectomy (MT) alone, MT with angioplasty, or MT with carotid artery stent placement is superior. We aim to address a gap in the literature comparing carotid stenting with mechanical thrombectomy (CSMT) and carotid angioplasty with mechanical thrombectomy (CAMT) in patients presenting with acute anterior circulation TOs. Methods This is a multicenter, retrospective study from 2012 to 2020 comparing CSMT and CAMT presenting with acute anterior circulation TOs. Primary outcomes of interest were functional status, perioperative stroke, mortality, and symptomatic intracranial hemorrhage (sICH). A total of 92 patients (66 vs. 26 in CSMT and CAMT, respectively) met inclusion criteria for analysis. Results There was no statistically significant difference in functional outcomes at 90-day follow-up (adjusted odds ratio [aOR] 0.82; 95% confidence interval [CI] 0.20–3.5; P = 0.46). In addition, there was no statistically significant difference in 90-day mortality (aOR 0.361; 95% CI 0.016–2.92; P = 0.532) and perioperative stroke rate (aOR 1.76; 95% CI 0.160–15.6; P = 0.613). However, sICH risk was significantly greater in the stent-treated cohort (aOR 3.94; 95% CI 0.529–37.4; P = 0.003). Conclusions Functional outcomes, mortality, and perioperative stroke rates do not significantly differ in CSMT and CAMT procedures in the acute setting. However, CSMT-treated patients do appear to have an increased risk of sICH, potentially due to the use of additional antiplatelet agents following stent placement.

The 2016 World Health Organization brain tumor classification is based on genomic and molecular profile of tumor tissue. These characteristics have improved understanding of the brain tumor and played an important role in treatment planning and prognostication. There is an ongoing effort to develop noninvasive imaging techniques that provide insight into tissue characteristics at the cellular and molecular levels. This article focuses on the molecular characteristics of gliomas, transcriptomic subtypes, and radiogenomic studies using semantic and radiomic features. The limitations and future directions of radiogenomics as a standalone diagnostic tool also are discussed.

Molecular features are now essential in distinguishing between glioma histologic subtypes. Currently, isocitrate dehydrogenase mutation, 1p19q codeletion, and MGMT methylation status play significant roles in optimizing medical and surgical treatment. Noninvasive pretreatment and post-treatment determination of glioma subtype is of great interest. Although imaging cannot replace the genetic panel at present, image findings have shown promising signs to identify and diagnose the types and subtypes of gliomas. This article details key imaging findings in the most common molecular glioma subtypes and highlights recent advances in imaging technologies to differentiate these lesions noninvasively.

Neoplastic meningitis (NM) and paraneoplastic syndromes (PNSs) are a rare group of disorders present in patients with cancer. Clinical diagnosis of these conditions is challenging, and imaging and laboratory analysis play a significant role in diagnosing. Diagnosis of NM largely depends on documenting circulating tumor cells in the cerebrospinal fluid (CSF) and/or leptomeningeal and nodular enhancement on contrast-enhanced MR imaging of the brain or axial spine. PNSs encompass a variety of symptoms or syndromes. Paraneoplastic neuronal disorder diagnosis requires a multidimensional approach, high clinical suspicion, CSF and serum examination, and imaging. Neuroimaging is an integral part in the evaluation.

Neurologic injury arises from treatment of central nervous system malignancies as result of direct toxic effects or indirect vascular, autoimmune, or infectious effects. Multimodality treatment may potentiate both therapeutic and toxic effects. Symptoms range from mild to severe and permanent. Injuries can be immediate or delayed. Many early complications are nonspecific. Other early and delayed neurologic injuries, such as posterior reversible encephalopathy syndrome, dural sinus thrombosis, infarctions, myelopathy, leukoencephalopathy, and hypophysitis, have unique imaging features. This article reviews treatment options for neurologic malignancies and common and uncommon neurologic injuries that can result from treatment, focusing on radiologic features.

Objectives/hypothesis Evaluate bone resorption in free fibular grafts and document resorption behavior as compared to dentulous and edentulous autochthonous mandibular bone. Study design Retrospective Chart review. Methods Postoperative computed tomography images were used to evaluate fibular graft resorption rates and corresponding sites of the dentulous or edentulous mandible. Bone height, width, and cortical thickness were measured. Results Eighteen patients underwent fibula free flap reconstruction following resection of a primary head and neck cancer. Mandibular defects were classified using Jewer's classification. The average interval loss of osseous height was 0.23 ± 0.09 mm/yr for fibula flap, 0.55 ± 0.13 mm/yr for dentulous native mandible, and 0.98 ± 0.41 mm/yr in edentulous native mandible. Change in osseous width was 0.19 ± 0.08 mm/yr, 0.55 ± 0.33 mm/yr, and 0.73 ± 0.15 mm/yr, respectively. Rate of superior cortical resorption was 0.33 ± 0.34 mm/yr, 0.35 ± 0.13 mm/yr, and 0.53 ± 0.11 mm/yr in fibula flap, dentulous, and edentulous mandible, respectively. Inferior cortical resorption rates were quantified as 0.30 ± 0.11 mm/yr, 0.35 ± 0.08 mm/yr, and 0.51 ± 0.08 mm/yr. Conclusions Fibula free flap reconstruction of the mandible provides excellent functional results and allows for stable outcomes. Bone resorption is significantly lower in fibular graft compared with both edentulous and dentulous mandible. Edentulous bone displays significantly increased rates of atrophy in comparison to the dentulous mandible. This may have implications with regard to long-term viability of both the fibular flap and native mandible. The role of dental restoration on overall osseous stability warrants further research. Level of evidence 4 Laryngoscope, 129:1113-1116, 2019.

The submandibular and sublingual salivary glands are major salivary glands with a wide spectrum of pathologic conditions. The corresponding spaces along the floor of mouth have complex anatomy, best evaluated with cross-sectional imaging. The spectrum of diseases in these regions varies from simple infection to advanced malignancy, not just from the gland itself but also from the surrounding structures. The most common abnormalities in these spaces are inflammatory and infectious, and computed tomography is currently the most common imaging modality used. The anatomy of these spaces is much better depicted with MR; however, all the modalities have their unique roles.

BACKGROUND AND PURPOSE: Both diffusion tensor imaging and the apparent transverse relaxation rate have shown promise in differentiating Parkinson disease from atypical parkinsonism (particularly multiple system atrophy and progressive supranuclear palsy). The objective of the study was to assess the ability of DTI, the apparent transverse relaxation rate, and their combination for differentiating Parkinson disease, multiple system atrophy, progressive supranuclear palsy, and controls. MATERIALS AND METHODS: A total of 106 subjects (36 controls, 35 patients with Parkinson disease, 16 with multiple system atrophy, and 19 with progressive supranuclear palsy) were included. DTI and the apparent transverse relaxation rate measures from the striatal, midbrain, limbic, and cerebellar regions were obtained and compared among groups. The discrimination performance of DTI and the apparent transverse relaxation rate among groups was assessed by using Elastic-Net machine learning and receiver operating characteristic curve analysis. RESULTS: Compared with controls, patients with Parkinson disease showed significant apparent transverse relaxation rate differences in the red nucleus. Compared to those with Parkinson disease, patients with both multiple system atrophy and progressive supranuclear palsy showed more widespread changes, extending from the midbrain to striatal and cerebellar structures. The pattern of changes, however, was different between the 2 groups. For instance, patients with multiple system atrophy showed decreased fractional anisotropy and an increased apparent transverse relaxation rate in the subthalamic nucleus, whereas patients with progressive supranuclear palsy showed an increased mean diffusivity in the hippocampus. Combined, DTI and the apparent transverse relaxation rate were significantly better than DTI or the apparent transverse relaxation rate alone in separating controls from those with Parkinson disease/multiple system atrophy/progressive supranuclear palsy; controls from those with Parkinson disease; those with Parkinson disease from those with multiple system atrophy/progressive supranuclear palsy; and those with Parkinson disease from those with multiple system atrophy; but not those with Parkinson disease from those with progressive supranuclear palsy, or those with multiple system atrophy from those with progressive supranuclear palsy. CONCLUSIONS: DTI and the apparent transverse relaxation rate provide different but complementary information for different parkinsonisms. Combined DTI and apparent transverse relaxation rate may be a superior marker for the differential diagnosis of parkinsonisms.

Olfactory impairment is associated with prodromal Alzheimer’s disease (AD) and is a risk factor for the development of dementia. AD pathology is known to disrupt brain regions instrumental in olfactory information processing, such as the primary olfactory cortex (POC), the hippocampus, and other temporal lobe structures. This selective vulnerability suggests that the functional connectivity (FC) between the olfactory network (ON), consisting of the POC, insula and orbital frontal cortex (OFC) (Tobia et al., 2016), and the hippocampus may be impaired in early stage AD. Yet, the development trajectory of this potential FC impairment remains unclear. Here, we used resting-state functional magnetic resonance imaging (rs-fMRI) data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to investigate FC changes between the ON and hippocampus in four groups: aged-matched cognitively normal (CN), early mild cognitive impairment (EMCI), late mild cognitive impairment (LMCI), and AD. FC was calculated using low frequency fMRI signal fluctuations in the ON and hippocampus (Tobia et al., 2016). We found that the FC between the ON and the right hippocampus became progressively disrupted across disease states, with significant differences between EMCI and LMCI groups. Additionally, there were no significant differences in gray matter hippocampal volumes between EMCI and LMCI groups. Lastly, the FC between the ON and hippocampus was significantly correlated with neuropsychological test scores, suggesting that it is related to cognition in a meaningful way. These findings provide the first in vivo evidence for the involvement of FC between the ON and hippocampus in AD pathology. Results suggest that functional connectivity (FC) between the olfactory network (ON) and hippocampus may be a sensitive marker for Alzheimer’s disease (AD) progression, preceding gray matter volume loss.

BackgroundThe unpredictability in presenting signs and symptoms of idiopathic sudden sensorineural hearing loss (SSNHL) presents a notable diagnostic challenge for clinicians. Previous studies have...

Background:Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features.Methods:A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths.Results:Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size.Conclusion:Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.

OBJECTIVE Bone-anchored hearing aid has been shown to be effective in hearing rehabilitation for conductive loss or single-sided deafness. Current FDA guidelines allow implantation in patients over 5 years old. This guideline is at least partially due to concern for thickness of bone stock at the implant site. We aim to investigate whether temporal bone thickness should be a deterrent to implantation in those younger than five. STUDY DESIGN A retrospective review of high-resolution temporal bone computed tomographies (CTs) comparing measurements between ears with chronic disease and controls. SETTING Single institution tertiary care center. PATIENTS One hundred patients between 1 and 5.99 years had temporal bone CTs performed between 2000 and 2009. Patients with chronic ear disease were identified by ICD-9 code, as well as confirmation by review of the imaging. INTERVENTION(S) None. MAIN OUTCOME MEASURES Temporal bone thickness was measured on axial CT slices at a point 1 cm posterior to the sigmoid sinus, at the superior margin of the bony canal. RESULTS Average thickness was greater than 3 mm in all age groups. No significant difference was found between age groups, or between normal ears and ears with chronic disease (3.5 mm versus 3.3 mm, p = 0.21) when compared individually. CONCLUSION This data shows pediatric temporal bone thickness is frequently greater than the recommended 3 mm, even in patients as young as one. Anatomically, concerns regarding temporal bone thickness in patients younger than five could be reliably addressed with imaging typically obtained in workup of hearing loss.

Multiple myeloma is the most common bone malignancy. Imaging plays an important role in identifying the extent of the disease, disease process, guiding biopsies, and diagnosing associated spinal and intracranial complications. Multiple myeloma and related plasma cell proliferative disorders have a diverse set of clinicopathologic findings and on neuroimaging present unique and diverse findings from the disease and from complications of the disease and treatment, which are valuable for clinicians and radiologists.

The hallmark signs and symptoms of anemia are directly related to a decrease in oxygen delivery to vital tissues and organs and include pallor, fatigue, lightheadedness, and shortness of breath. Neurologic complications are often nonspecific and can include poor concentration, irritability, faintness, tinnitus, and headache. If undiagnosed or untreated, anemia can progress to cognitive dysfunction, psychosis, encephalopathy, myelopathy, peripheral neuropathy, and more focal syndromes, such as stroke, seizures, chorea, and transverse myelitis. Imaging can play an important role in the early diagnosis and treatment of these neurologic and systemic complications associated with anemia, and hence, better outcome.

Bone marrow is the essential for function of hematopoiesis, which is vital for the normal functioning of the body. Bone marrow disorders or dysfunctions may be evaluated by blood workup, peripheral smears, marrow biopsy, plain radiographs, computed tomography (CT), MRI and nuclear medicine scan. It is important to distinguish normal spinal marrow from pathology to avoid missing a pathology or misinterpreting normal changes, either of which may result in further testing and increased health care costs. This article focuses on the diffuse bone marrow pathologies, because the majority of the bone marrow pathologies related to hematologic disorders are diffuse.

Hematologic disorders affect the central nervous system in a variety of ways, producing a wide range of neurologic disturbances. Early identification of these complications allows for early intervention and better outcome. Cross-sectional imaging plays an important role in identifying brain abnormalities and helps the clinician in deciding appropriate course of action and treatment. This article discuss in short the basics of hemostasis including the coagulation cascade and the application of basic laboratory tests in evaluation of hematologic function. Imaging features of various neurologic disorders associated with these clotting and bleeding diatheses are discussed in detail with illustrations.

Non-atherosclerotic vasculopathies (NAVs) may present with various neurological symptoms ranging from headache, stroke, visual symptoms, and various types of intracranial hemorrhage. NAVs result from different etiologies which include collagenopathies, immunological, hematological, and infection mechanisms, and other rarer unidentifiable or idiopathic causes. NAV etiologies account for about 10–15% and 20–25% of adult and pediatric stroke cases, respectively, and therefore, diagnosing the underlying cause of NAV becomes clinically very important. Clinical diagnosis of NAV is challenging because the clinical presentation is very non-specific and overlapping with various other central nervous system disorders. Before the advent of non-invasive techniques, making a diagnosis of non-atherosclerotic vasculopathy as a cause of the stroke was very challenging. Today with newer techniques such as high-resolution magnetic resonance (MR), MR and computed tomography perfusion, and angiogram, there are number of pointers which can give us a lead about the non-atherosclerotic causes. Imaging may provide the first lead to the clinician regarding the diagnosis or possible differential diagnosis so that the targeted and focused biomarkers (blood, cerebrospinal fluid, or/and in some cases biopsies) may be obtained to clinch the diagnoses. The purpose of the article is to enumerate the causes, clinical features, and illustrate the imaging findings of the various non-atherosclerotic vasculopathic disorders and discuss “pearls” to their diagnosis. In this article, we have also discussed the latest advances in vascular imaging and elaborated on few uncommon non-atherosclerotic vasculopathies. These are very relevant clinically in the day-to-day practice for the radiologist, neurologist, and the neurointerventionalist.

Previous multimodal magnetic resonance imaging (MRI) studies of parkinsonian syndromes have focused primarily on motor-related basal ganglia structures. The present study investigated MRI changes in nonmotor-related limbic structures in 35 Parkinson's disease, 16 multiple system atrophy parkinsonian subtype, 17 progressive supranuclear palsy, and 37 control subjects. Mean diffusivity (MD), fractional anisotropy, transverse relaxation rate (R2*), quantitative susceptibility mapping, and volume measurements were obtained from the amygdala, hippocampus, and nucleus accumbens (NAc) to examine differences between groups and to test for associations with clinical scores. Compared with controls, Parkinson's disease subjects had lower NAc volume; multiple system atrophy parkinsonian subtype subjects had higher NAc transverse relaxation rate; and progressive supranuclear palsy subjects had higher amygdala and hippocampus MD and lower hippocampus fractional anisotropy (p's ≤ 0.008). Among parkinsonian subjects, amygdala and hippocampus MD associated positively with Unified Parkinson's Disease Rating Scale nonmotor and activities of daily living scores (p's ≤ 0.005). Together, these findings support the inclusion of limbic structures in future MRI studies of parkinsonian syndromes.

// John Varlotto 1 , John Flickinger 2 , Martin T. Pavelic 3 , Charles S. Specht 4 , Jonas M. Sheehan 5, 6 , Dana T. Timek 4 , Michael J. Glantz 5, 6 , Steven Sogge 7 , Christopher Dimaio 8 , Richard Moser 9 , Shakeeb Yunus 10 , Thomas J. Fitzgerald 1 , Urvashi Upadhyay 9 , Paul Rava 1 , Matthew Tangel 11 , Aaron Yao 12 , Sangam Kanekar 7 1 University of Massachusetts Medical Center, Department of Radiation Oncology, Worcester, MA, USA 2 University of Pittsburgh Medical Center, Department of Radiation Oncology, Pittsburgh, PA, USA 3 Columbia University Medical Center, Department of Anesthesia, New York, NY, USA 4 Penn State Hershey Medical Center, Department of Pathology, Hershey, PA, USA 5 Penn State Hershey Medical Center, Department of Neurosurgery, Hershey, PA, USA 6 Penn State Hershey Neuroscience Institute, Hershey, PA, USA 7 Penn State Hershey Medical Center, Department of Radiology, Hershey, PA, USA 8 Penn State Hershey Medical Center, Department of Neurology, Hershey, PA, USA 9 University of Massachusetts Medical Center, Division of Neurosurgery, Worcester, MA, USA 10 University of Massachusetts Medical Center, Department of Medical Oncology, Worcester, MA, USA 11 Penn State College of Medicine, Hershey, PA, USA 12 Department of Healthcare Policy and Research, Virginia Commonwealth University, Richmond, VA, USA Correspondence to: John M. Varlotto, e-mail: john.varlotto@umassmemorial.org Keywords: meningioma, MRI, cerebrovascular accident, tumor vascularity Received: July 08, 2015 Accepted: September 28, 2015 Published: October 09, 2015 ABSTRACT Background: Many meningiomas are identified by imaging and followed, with an assumption that they are WHO Grade I tumors. The purpose of our investigation is to find clinical or imaging predictors of WHO Grade II/III tumors to distinguish them from Grade I meningiomas. Methods: Patients with a pathologic diagnosis of meningioma from 2002–2009 were included if they had pre-operative MRI studies and pathology for review. A Neuro-Pathologist reviewed and classified all tumors by WHO 2007. All Brain MRI imaging was reviewed by a Neuro-radiologist. Pathology and Radiology reviews were blinded from each other and clinical course. Recursive partitioning was used to create predictive models for identifying meningioma grades. Results: Factors significantly correlating with a diagnosis of WHO Grade II-III tumors in univariate analysis: prior CVA ( p = 0.005), CABG ( p = 0.010), paresis ( p = 0.008), vascularity index = 4/4: ( p = 0.009), convexity vs other ( p = 0.014), metabolic syndrome ( p = 0.025), non-skull base ( p = 0.041) and non-postmenopausal female ( p = 0.045). Recursive partitioning analysis identified four categories: 1. prior CVA, 2. vascular index (vi) = 4 (no CVA), 3. premenopausal or male, vi < 4, no CVA. 4. Postmenopausal, vi < 4, no CVA with corresponding rates of 73, 54, 35 and 10% of being Grade II-III meningiomas. Conclusions: Meningioma patients with prior CVA and those grade 4/4 vascularity are the most likely to have WHO Grade II-III tumors while post-menopausal women without these features are the most likely to have Grade I meningiomas. Further study of the associations of clinical and imaging factors with grade and clinical behavior are needed to better predict behavior of these tumors without biopsy.

OBJECTIVE Current bone-anchored hearing aid (BAHA) guidelines recommend placement of the titanium implant 5 to 7 cm posterior to the ear canal. Previous studies show that bone conducted hearing is maximized the closer the transducer is to the cochlea. We aim to investigate the position of the sigmoid sinus with respect to BAHA implants to determine whether they may be safely placed closer to the ear canal in patients with chronic ear disease, enhancing the amplification available to the patient. STUDY DESIGN We performed a retrospective review of high-resolution temporal bone computed tomographies (CTs), comparing multiple measurements between ears with chronic ear disease and normal controls. SETTING Images were obtained at a single academic medical center. PATIENTS Eighty patients (160 ears) with temporal bone CTs performed between 2006 and 2009 were measured. Patients with chronic ear disease were identified by international statistical classification of diseases and related health problems, revision 9 code and confirmation by review of the imaging. MAIN OUTCOME MEASURES Measurements were made on axial CT slices from a point 1 cm posterior to the sigmoid sinus to the posterior margin of the external canal. The squamous temporal bone thickness was also measured at this point. RESULTS Forty-seven patients (55 ears) had chronic ear disease. Distance from the posterior canal was significantly different between normal and diseased ears (36.3 mm versus 33.5 mm, p

Developmental venous anomaly (DVA), formally known as venous angioma, is a congenital anatomic variant of the venous drainage of the brain. Although they typically have a benign clinical course and a low symptomatic rate, thrombosis of a drainage vein may occur, leading to potentially debilitating complications. We report a unique case of spontaneous thrombosis of a posterior fossa developmental venous anomaly with cerebellar infarct in a 61-year-old man who presented with acute onset cerebellar ataxia. DVA thrombosis was well-depicted on CT and MR studies. Patient was put on anticoagulant therapy and complete recanalization was seen on follow-up imaging.

Neonatal metabolic encephalopathy may be related to electrolyte imbalances, endocrine dysfunction, or inborn errors of metabolism. The metabolic encephalopathies are always a diagnostic challenge to the neonatologist and pediatricians. This is more so because the signs and symptoms of are nonspecific and are often similar to those with other neonatal emergencies. Clinical suspicion of neonatal encephalopathy should be considered in any infant exhibiting an abnormal level of consciousness, seizures, tone and reflex abnormalities, apnea, aspiration, and feeding difficulties. A definitive diagnosis is frequently not possible during the neonatal care unit or emergency department. But the proper initial management based on the probable diagnosis can be life-saving or reduce neurologic sequelae. In the case of inborn errors of metabolism, imaging may play a vital role either in limiting the differential diagnosis or yet times pointing towards the specific diagnosis or error of metabolism. We report DWI-ADC changes on MRI in the acute stages of neonatal nonketotic hyperglycinemia (NKH) due to sequence changes in GLDC gene.

A number of physiologic, hormonal, immunologic, and hemodynamic changes take place in the maternal body during pregnancy. The majority of these changes are essential for maintaining the normal course of pregnancy. However, these changes may also cause acute or chronic conditions that affect various biologic systems in the mother. In addition, conditions of the central and peripheral nervous systems can cause a variety of neurologic symptoms and complications. Neurologic signs and symptoms in pregnant and postpartum women may be due to the exacerbation of a preexisting medical condition, the initial manifestation of a primary central nervous system-related problem, or a neurologic problem unique to pregnancy and the postpartum period. Because the symptoms of these conditions are either nonspecific or overlapping, it can be challenging to pinpoint the diagnosis clinically. These conditions can be classified into more commonly seen conditions such as headache, venous thrombosis, preeclampsia, subarachnoid hemorrhage, posterior reversible encephalopathy syndrome, and certain pituitary disorders; and less commonly seen entities such as aneurysm, arteriovenous malformation, primary or secondary neoplasm, Sheehan syndrome, and Wernicke encephalopathy. Imaging has an important role in the differentiation and exclusion of various neurologic conditions, and most of the time, imaging findings can point the clinician to a specific diagnosis. The imaging appearances of common and uncommon neurologic conditions that can occur during pregnancy and the early postpartum period are highlighted in this article.

Hydrocephalus basically means an increase in the volume of cerebrospinal fluid (CSF) and the ventricles. As simple as it may sound, the definition and classification of hydrocephalus have been a matter of debate over many decades. Many international neurosurgical and radiological workgroups have tried to develop a consensus and over the last 5-10 years have been able to put forth a more well-defined and standardized approach. Though, the debate and controversy surrounding this topic is expected to continue, we have tried to review the most recent and consensually accepted definition and classification. Although conventionally classified as either "obstructive and nonobstructive" or "communicating and noncommunicating," none of the classification schemes were without confusion and errors. A more precise nomenclature is to divide hydrocephalus as either "communicating": with or without obstruction of CSF absorption, or as "noncommunicating": with definite obstruction to CSF absorption. We discuss communicating hydrocephalus in the current article, and the subsequent article deals with noncommunicating hydrocephalus.

A cerebrospinal fluid (CSF) shunt is an internalized system used for the treatment of hydrocephalus and connects the ventricular system to the peritoneal space, right atrium, or the pleural space. The CSF shunt malfunction can occur due to obstruction, migration, overdrainage, infection, or CSF accumulation at the distal end. Although conventional radiography and radionuclide studies are used for evaluation of integrity of the shunts, computed tomography, ultrasound, and magnetic resonance imaging are used for the evaluation of shunt obstruction, migration, CSF accumulations, infections, overdrainage, and other complications. We discuss the different types and components of the CSF shunt, as this is important for the evaluation of the shunt integrity. Imaging of various causes of CSF shunt malfunction and the complications related to CSF shunts would be illustrated.

Metronidazole is a very common antibacterial and antiprotozoal with wide usage across the globe, including the least developed countries. It is generally well-tolerated with a low incidence of serious side-effects. Neurological toxicity is fairly common with this drug, however majority of these are peripheral neuropathy with very few cases of central nervous toxicity reported. We report the imaging findings in two patients with cerebellar dysfunction after Metronidazole usage. Signal changes in the dentate and red nucleus were seen on magnetic resonance imaging in these patients. Most of the cases reported in literature reported similar findings, suggesting high predilection for the dentate nucleus in metronidazole induced encephalopathy.

The authors present imaging anatomy of the parotid space and discuss non-neoplastic lesions, autoimmune disorders, cysts, neoplastic lesions, epithelial tumors, and nonepithelial lesions. They describe the diseases and their appearance on imaging, describing how the differential diagnoses appear, along with presenting examples of the images, primarily computed tomography and magnetic resonance imaging.

The mylohyoid muscle divides the lower part of the oral cavity into 2 spaces: the sublingual space, which is located superior to the muscle, and the submandibular space, inferior to the muscle but superior to the hyoid bone. Although the submandibular and sublingual spaces are small, a wide range of pathologic processes may involve these spaces. They include cystic lesions, inflammatory conditions with various causes, rare vascular lesions, and benign and malignant neoplasms. This article outlines the radiologic anatomy of the region, describes the various pathologic processes that may affect it, and discusses the use of imaging in their evaluation.

OBJECTIVE. Stroke is the third leading cause of death and the leading cause of severe disability. During the ???decade of the brain??? in the 1990s, the most promising development was the treatment of acute ischemic stroke. It is thought to result from a cascade of events from energy depletion to cell death. In the initial minutes to hour, clinical deficit does not necessarily reflect irreversible damage. The final outcome and residual deficit will be decided by how fast reperfusion is achieved, which in turn depends on how early the diagnosis is made. This article explains the pathophysiology of stroke at the molecular and cellular levels with corresponding changes on various imaging techniques. CONCLUSION. The pathophysiology of stroke has several complex mechanisms. Understanding these mechanisms is essential to derive neuroprotective agents that limit neuronal damage after ischemia. Imaging and clinical strategies aimed at extending the therapeutic window for reperfusion treatment with mechanical and ...

Dorsal induction includes the formation and closure of neural tube, occurs during 3-5 weeks of gestation. Neurulation occurs in two phases, primary neurulation (formation of the neural plate and subsequently neural tube) and secondary neurulation (formation of distal cord and sacral and coccygeal segments). Failure of dorsal induction leads to anencephaly, exencephaly, cephaloceles, Chiari malformation and spinal dysraphism. In this article we discuss the relevant embryology, etiopathology and detail imaging appearances of these malformations.

The ingestion of ethylene glycol results in toxicity with characteristic chemical, pathological, and imaging findings. In the case presented, magnetic resonance imaging demonstrated bilateral symmetric hyperintensity within the basal ganglia, thalami, and brainstem. Ethylene glycol toxicity also resulted in restricted diffusion within the white matter tracts of the corona radiata, a finding not previously described in the literature. In the acute clinical setting, ethylene glycol toxicity is an important differential consideration of the pathologies involving the deep grey matter nuclei.

Intraspinal hemorrhage is very rare and intramedullary hemorrhage, also called hematomyelia, is the rarest form of intraspinal hemorrhage, usually related to trauma. Spinal vascular malformations such intradural arteriovenous malformations are the most common cause of atraumatic hematomyelia. Other considerations include warfarin or heparin anticoagulation, bleeding disorders, spinal cord tumors. Radiation-induced hematomyelia of the cord is exceedingly rare with only one case in literature to date. We report the case of an 8 year old girl with Ewing’s sarcoma of the thoracic vertebra, under radiation therapy, presenting with hematomyelia. We describe the clinical course, the findings on imaging studies and the available information in the literature. Recognition of the clinical pattern of spinal cord injury should lead clinicians to perform imaging studies to evaluate for compressive etiologies.

Introduction: The motor symptoms and signs of early-onset idiopathic Parkinson's disease (PD) in Hoehn and Yahr (H&Y) stage-1 are generally unilateral. We hypothesized that there would be detectable differences in the quantitative MRI parameters in these PD patients between the hemispheres contralateral to the clinically symptomatic and non-symptomatic body side. Methods: We tested this hypothesis by comparing transverse relaxation rates and diffusion tensor imaging (DTI) parameters in the substantia nigra and putamen between the two hemispheres contralateral to the symptomatic and non-symptomatic side in H&Y stage-1 PD patients who had onset of symptoms between ages of 40e59 years. Results: There were quantifiable hemispheric asymmetries in transverse relaxation rates in the substantia nigra, as well as fractional anisotropy and mean diffusivity in the putamen in early PD, which correlated with the unilaterality of motor symptoms as evaluated using the motor portion of the Unified Parkinson's Disease Rating Scale. Conclusion: Transverse relaxation mapping and DTI demonstrated significant differences between the symptomatic and non-symptomatic hemispheres at the early stage of early-onset PD. These findings support the hypothesis of asymmetric neurodegeneration in the bilateral nigrostriatal pathways in the early stage of the disease.

Evaluation of focal white matter hyperintensities on magnetic resonance imaging in any age group is always challenging because the cause of these hyperintensities varies extensively. Understanding the clinical presentation, pathophysiology, and associated imaging findings can allow the radiologist to limit the differential diagnosis. A specific imaging approach including age, pattern of distribution, signal characteristics on various sequences, enhancement pattern, and other ancillary findings helps to identify a correct cause for these hyperintensities. This article provides a pattern approach to differentiate various common and a few uncommon diseases presenting as focal white matter hyperintensities.

When atrophy is seen on imaging in adult patients, it does not necessarily represent Alzheimer disease. Many cases of dementia or cognitive decline could be caused by reversible or preventable diseases, such as vascular dementia. This article familiarizes the physician with various types of vascular lesions leading to dementia and cognitive decline and their imaging appearances. Neuroimaging plays an important role in identifying vascular lesions of the brain early, even before the clinical manifestation of the cognitive decline symptoms and, thus, can help to prevent or delay the symptoms related to the various vascular pathologic conditions.

In clinically suspected cases of myelopathy, magnetic resonance imaging without and with gadolinium remains the modality of choice. The first and best imaging approach in the evaluation of myelopathy is to identify whether the cause of myelopathy is compressive or noncompressive. The commonest imaging finding in myelopathy is either focal or diffuse cord hyperintensity on the T2-weighted magnetic resonance images. Detailed clinical history, acuity of symptoms (acute vs insidious onset), distribution of the signal abnormalities, including length of cord involvement, specific tract involvement, and the region of the spinal cord that is affected, are very useful in making the diagnosis.

This 6-month-old girl was transferred from an outside hospital, unaccompanied by her parents. She had a period of emesis and was taken to her primary care physician, who noticed bilateral parasternal bruising concerning for nonaccidental trauma. Cranial computed tomography showed bilateral subdural hematomas. She was admitted and evaluated for nonaccidental injury. Funduscopic eye examination revealed bilateral retinal hemorrhages. Magnetic resonance imaging of the brain demonstrated bilateral subdural hemorrhages of different signal intensities, extending into the lumbar spine. Spinal subdural hematoma (Figs 1 and 2) appeared hyperintense on both T1and T2weighted images with signal dropout on the gradient images, thereby confirming blood products. She was stable and no acute neurosurgical intervention was deemed necessary. History was gleaned from the parents and the primary care doctor. It was concluded that the girl’s findings were secondary to nonaccidental trauma.

Febrile infection-related epilepsy syndrome (FIRES) is a catastrophic and usually refractory epilepsy syndrome that occurs after a febrile illness in previously normal children. The pathogenesis of the syndrome is unknown, and the diagnosis is typically made by exclusion after an exhaustive negative workup for central nervous system infections and autoimmune or metabolic disorders. Magnetic resonance imaging of patients with this condition has previously shown hippocampal abnormalities, typically found several months or longer after initial seizures. We report a previously healthy 5-year-old child who developed hippocampal atrophy by day 37 of his illness. The development of early hippocampal atrophy in this epileptic encephalopathy may provide insight into pathogenesis and highlights the need for aggressive and effective interventions early in the disease process.

This article presents a comprehensive analysis of the neck fascia and neck spaces that are formed by the interplay of the different fascial layers. Because a solid and thorough understanding of the anatomy and relationship of the various neck spaces is so valuable in diagnosing and treating diseases of the neck, this information organizes the anatomic areas of the neck beginning with and overview, followed by extent, anatomic relationship, and contents. Detailed enhanced computed tomography images display the anatomic areas of the neck.

The most common of the lesions in the carotid space are discussed in relation to their radiographic diagnosis and clinical implications. The appearance of tumors and lesions on computed tomography or magnetic resonance imaging is presented, and their differential diagnosis is discussed. The image of each carotid disease is presented, and the discussion concludes with treatment recommendations and considerations.

Due to nonspecific clinical presentation, diagnosis of metabolic disorders affecting the brain is very challenging for physicians. It is always the constellation of the clinical examination, biochemical assay and imaging that helps in reaching the diagnosis of metabolic disorders. Diagnosis of these disorders or even limiting the differential diagnosis on imaging may pose a formidable challenge to the radiologist. In these two articles (Metabolic Disorders of the Brain: Parts I and II) we have tried to highlight the important clinical and imaging pearls of the major and more commonly encountered metabolic disorders. In the first article we discuss metabolic disorders related to dysfunction of the cellular organelle namely lysosomal, peroxisomal, and mitochondrial. We have also discussed the relevant genetic abnormalities, biochemical findings and application of newer imaging techniques which may aid in diagnosis of these various disorders.