Ethylene Glycol Toxicity: Chemistry, Pathogenesis, and Imaging

AbstractThe 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

Distinguishing grade I meningioma from higher grade meningiomas without biopsy

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 \u3c 4, no CVA. 4. Postmenopausal, vi \u3c 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

Radiation-induced spinal cord hemorrhage (hematomyelia)

Intraspinal hemorrhage is very rare and intramedullary hemorrhage, also called <em>hematomyelia</em>, 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

Hippocampal changes in Febrile infection-related epilepsy syndrome (FIRES)

BACKGROUND: Febrile seizures are the most common seizure disorder in childhood, associated with a significant rise in body temperature. However, post-infectious refractory afebrile form of seizures in previously healthy children is being increasingly recognized in around the world, which evolves into a chronic refractory form of epilepsy. The term 'Febrile infection-related epilepsy syndrome' (FIRES) has been proposed for these conditions and represents a refractory severe post-infectious epileptic condition in previously normal children. CASE REPORT: We report the initial and follow-up MR imaging findings in a 5year-old with refractory epilepsy post-febrile seizures. CONCLUSIONS: In summary, acute post-infectious seizures are increasingly being recognized across the globe with the newly coined term 'Febrile infection-related epilepsy syndrome' (FIRES) for this group of immune-mediated epileptic encephalopathy in previously healthy children. This has three phases: episode of simple febrile infection, followed by acute refractory seizures and lastly the chronic phase of neuropsychological impairments and seizures

Value of quantitative apparent diffusion coefficients in differentiating low-grade gliomas from mixed neuronal-glial tumors

Purpose: To retrospectively assess if diffusion-weighted MR imaging (DWI) and quantitative apparent–diffusion coefficient (ADC) maps could be used to differentiate between low-grade gliomas (LGGs) and mixed neuronal–glial tumors (MNGTs including Dysembryoplastic Neuroepithelial Tumor and Ganglioglioma). Materials and methods: We retrospectively searched the clinical, pathological, and radiological databases for a span of 9 years and identified 24 patients with biopsy proven LGG. This included WHO (fourth edition) grade I and II tumors including astrocytoma, oligoastrocytoma and oligodendrogliomas. We also identified 22 patients with MNGTs (WHO grade I) including 13 patients with DNET and 9 patients with Ganglioglioma. All patients with pathologically confirmed tumors who had MRI including DWI sequence were included in the study. Regions of interest (ROIs) of 0.1–0.15 cm2 were manually positioned on the ADC maps and multiple values (10−6 mm2/s) were obtained including the ADCmean. Optimal thresholds of ADC values and ADC ratios for distinguishing low-grade gliomas from mixed neuronal–glial tumors were determined by receiver operating characteristic (ROC) curve analysis. Results: All the four ADC measurement variables, including the minimum (ADC min), the (ADC max) maximum, the mean of ADC values (ADC mean) and the ADC ratios (ADC mean/ADCnormal) showed significant difference between the MNGTs and LGGs. The most significant difference was seen with the maximum ADC value (ADC max) of the tumor where the values for LGGs were 1317 ± 314 whereas the values for MNGTs were 2134 ± 438. In both subsets of patients with MNGTs (DNET and Ganglioglioma), this difference was statistically significant (P = .015 and P = .0066, respectively). However, there was no significant difference between the ADC values of these subtypes of MNGTs. Conclusion: The ADC values of MNGTs are significantly higher compared to LGGs and can be helpful in radiological demarcation of these two conditions. The high ADC of MNGTs may be attributable to the presence of large extracellular spaces and their cellularity, which is much lower than that of pure glial neoplasms

Metronidazole-induced cerebellar toxicity

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

Sensitivity of 3D gradient recalled echo susceptibility-weighted imaging technique compared to computed tomography angiography for detection of middle cerebral artery thrombus in acute stroke

We aimed at comparing the sensitivity of magnetic resonance (MR) susceptibility-weighted imaging (SWI) with computed tomography angiography (CTA) in the detection of middle cerebral artery (MCA) thrombus in acute stroke. Seventy-nine patients with acute MCA stroke was selected using our search engine software; only the ones showing restricted diffusion in the MCA territory on diffusion-weighted images were included. We finally selected 35 patients who had done both MRI (including SWI) and CTA. Twenty random subjects with completely normal MRI (including SWI) exam were selected as control. Two neuroradiologists (blinded to the presence or absence of stroke) reviewed the SW images and then compared the findings with CT angiogram (in patients with stroke). The number of MCA segments showing thrombus in each patient was tabulated to estimate the thrombus burden. Thrombus was detected on SWI in one or more MCA segments in 30 out of 35 patients, on the first review. Of the 30, SWI showed thrombus in more than one MCA segments in 7 patients. CTA depicted branch occlusion in 31 cases. Thrombus was seen on both SWI and CTA in 28 patients. Thrombus was noted in two patients on SWI only, with no corresponding abnormality seen on CTA. Two patients with acute MCA showed no vascular occlusion or thrombus on either CTA or SWI. Only two case of false-positive thrombus was reported in normal control subjects. Susceptibility-weighted images had sensitivity and specificity of 86% and 90% respectively, with positive predictive value 94%. Sensitivity was 86% for SWI, compared with 89% for CTA, and this difference was statistically insignificant (P&gt;0.05). Of all the positive cases on CTA (31) corresponding thrombus was seen on SWI in 90% of subjects (28 of 31). Susceptibility-weighted imaging has high sensitivity for detection of thrombus in acute MCA stroke. Moreover, SWI is a powerful technique for estimation of thrombus burden, which can be challenging on CTA