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.

Pyolaryngocele Presenting with Acute-onset Stridor.

Case presentation: This case describes the classic imaging findings of pyolaryngocele and highlights the importance of prompt imaging for diagnosis of clinically occult airway lesions. The case also highlights how pyolaryngoceles can become large and present with acute-onset clinical symptoms, including stridor and dyspnea. Discussion: Pyolaryngoceles represent an uncommon but life-threatening complication of laryngoceles. Laryngoceles are frequently seen as an incidental, abnormal, air-filled dilation of the laryngeal saccule related to various local pathologies of the larynx. They are often asymptomatic. Occasionally they can become secondarily infected, in which case they are called pyolaryngocele, and they can cause rapid-onset, life-threatening airway compromise.

Quantifying disruption of workflow by phone calls to the neuroradiology reading room.

INTRODUCTION: The purpose of this study was to understand the source and the reason for the phone calls to our neuroradiology suit and to quantify the size of the problem in terms of duration of individual and aggregated calls. MATERIALS AND METHODS: Observation of the neuroradiology reading room for the entire duration of the working hours over three non-consecutive days was performed, and included telephone calls start time, end time and calls duration for incoming telephone calls. After each phone call the recipients were queried on the details of the phone call; the origin of the call, the reason for the call and the response. RESULTS: The average total number of minutes (min) spent on the phone each day was 64 min per working day with a total of 39 phone calls per day and 4.4 per hour on average. The trainees answered 71% of the phone calls with additional intervention by attending in 13% of phone calls. The most common source of phone calls was from either the MRI/CT technicians (48%), followed by providers (20%) and returning pages (18%). CONCLUSION: Cumulative time spent on the phone by neuroradiologists in the reading room ended up in more than an hour per working day, while trainees were taking the majority of phone calls. Most phone calls originated from technicians, hence, requiring specific solutions to mitigate this kind of interruption.

Radiation Reduction in Low Dose Pulsed Fluoroscopy versus Standard Dose Continuous Fluoroscopy during Fluoroscopically-Guided Lumbar Punctures: A Prospective Controlled Study.

PURPOSE: The purpose of this study was to evaluate radiation dose reduction in fluoroscopically guided lumbar punctures (FGLP) using "pulsed fluoroscopy in a low dose mode" compared with the commonly used "continuous fluoroscopy in a standard dose mode" while maintaining the technical success. MATERIALS AND METHODS: Thirty-five consecutive patients who underwent FGLP divided randomly to seventeen patients in the control group with standard dose continuous FGLP and eighteen patients in the study group with low-dose low-frame-rate of 3 frames per second (fps) FGLP. Entrance surface dose measurements from a dosimeter device were recorded as well as the dose area product (DAP). RESULTS: A total of 35 patients with average age of 52 years (range: 15-87 [±17 standard deviation [SD]]) were evaluated. Average entrance surface dose of the study group was significantly lower (3.81 mGy [range: 0.21-11.14, [±2.8 SD]]) compared with the control group (22.45 mGy [range: 1.23-73.44, [±19.41 [SD]]). The average DAP of the study group (10 mGy·cm2 [range: 1-41, [±9.8 SD]]) was also significantly lower than the control group (65 mGy·cm2 [range: 5-199, [±53 SD]]). Success rate was similar between the study and control groups. CONCLUSION: Low dose pulsed fluoroscopy of 3 fps significantly reduces radiation exposure by about 600% compared with standard dose continuous fluoroscopy in FGLP. Utilizing this radiation saving strategy will allow to dramatically reduce radiation exposure, without impacting the technical success rate.

Hypertrophic olivary degeneration: Case series and review of literature.

Hypertrophic Olivary Degeneration (HOD) is a rare neurological condition caused by trans-synaptic degeneration in the brainstem and cerebellum, resulting in varied clinical symptoms, classical being palatal tremors, along with characteristic imaging presentation. Large number of pathologic lesions can cause this condition, ranging from ischemic stroke to neoplasm. The most common conditions include hemorrhage, vascular malformations and infarct. Magnetic resonance scan (MRI) is the imaging modality of choice which shows signal changes with hypertrophy of the inferior olivary nucleus, as well as the primary underlying pathology. Through this pictorial essay, we present the imaging and clinical findings in a number of patients with HOD secondary to varied causes and explain the mechanism behind the changes.

Imaging Manifestations of Neurologic Complications in Anemia.

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.

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.

A Comparison of Magnetic Resonance Angiography Techniques for the Evaluation of Intracranial Aneurysms Treated With Stent-assisted Coil Embolization.

AIM: To identify the effective magnetic resonance angiography (MRA) technique to monitor intracranial aneurysms treated with stent-assisted coiling. MATERIALS AND METHODS: Retrospective analysis of various MRA techniques was performed in 42 patients. Three neuroradiologists independently compared non-contrast time of flight (ncTOF) MRA of the head, contrast-enhanced time of flight (cTOF) MRA of the head and dynamic contrast-enhanced MRA (CEMRA) of the head and neck or of the head. Digital subtraction angiography (DSA) was available for comparison in 32 cases. Inter-rater agreement (kappa statistic) was assessed. RESULTS: Artifactual in-stent severe stenosis or flow gap was identified by ncTOF MRA in 23 of 42 cases (55%) and by cTOF MRA in 23 of 38 cases (60%). DSA excluded in-stent stenosis or occlusion in all 32 cases. No difference was noted between ncTOF and cTOF in the demonstration of neck remnants or residual aneurysms in three cases each. CEMRA of the head and neck or of the head was rated superior to ncTOF and cTOF MRA by all three investigators in seven out of eight cases. In one case, all three techniques demonstrated signifcant artifacts due to double stent placement during coiling. The kappa statistic revealed 0.8 agreement between investigators. CONCLUSIONS: In the assessment of stent-assisted coiling of intracranial aneurysm, both ncTOF and cTOF MRA show similar results. CEMRA tends to show better flow signals in stent and residual aneurysm.

Epstein-Barr virus encephalitis presenting as cerebellar hemorrhage.

Epstein-Barr virus (EBV) belongs to the human herpesvirus family and is ubiquitously found in the adult human population. The most common clinical manifestation of EBV is the syndrome of infectious mononucleosis. Central nervous system involvement by EBV is rare, with very few cases of EBV encephalitis reported in the literature. The majority of these cases report cerebral cortical changes on magnetic resonance imaging. We present a rare case of EBV encephalitis in a young patient with meningitis-like symptoms and cerebellar hemorrhage on magnetic resonance imaging.