Comparison of arterial spin labeling and dynamic susceptibility contrast perfusion MR imaging in pediatric brain tumors: A systematic review and meta-analysis.

BACKGROUND: Brain tumors are a leading cause of mortality in children. Accurate tumor grading is essential to plan treatment and for prognostication. Perfusion imaging has been shown to correlate well with tumor grade in adults, however there are fewer studies in pediatric patients. Moreover, there is no consensus regarding which MR perfusion technique demonstrates the highest accuracy in the latter population. PURPOSE: To compare the diagnostic test accuracy of dynamic-susceptibility contrast and arterial spin-labelling, in their ability to differentiate between low-and high-grade pediatric brain tumors at first presentation. DATA SOURCES: Articles were retrieved from online electronic databases: MEDLINE (Ovid), Web of Science Core Collection and SCOPUS. STUDY SELECTION: Studies in pediatric patients with a treatment naïve diagnosed brain tumor and imaging including either ASL or DSC or both, together with a histological diagnosis were included. Studies involving adult patient or mixed age populations, studies with incomplete data and those which used dynamic contrast enhanced perfusion were excluded. DATA ANALYSIS: The sensitivities and specificities obtained from each study were used to calculate the true-positive, true-negative, false-positive, and false-negative count. A case was defined as a histologically proven high-grade tumor. The random-effect model was used to merge statistics. Significance level was set at p < 0.05. DATA SYNTHESIS: Forest plots showing pairs of sensitivity and specificity, with their 95% confidence intervals, were constructed for each study. The bivariate model was applied in order to account for between-study variability. The SROC plots were constructed from the obtained data-sets. The AUC for the SROC of all studies was estimated to determine the overall diagnostic test accuracy of perfusion MRI, followed by a separate comparison of the SROC of ASL versus DSC studies. LIMITATIONS: Small and heterogenous sample size. CONCLUSIONS: The diagnostic accuracy of ASL was found to be comparable and not inferior to DSC, thus its use in the diagnostic assessment of pediatric patients should continue to be supported. ABBREVIATIONS: ASL = arterial spin labelling, DSC = dynamic susceptibility contrast, DCE = dynamic contrast-enhanced, rCBF = relative cerebral blood flow, rCBV = relative cerebral blood volume, MTT = mean transfer time, TR = repetition time, TE = echo time, SROC = summary receiver operating characteristics, HG= high-grade, LG = low-grade, AUC = area under the curve, PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

The Chronically Blocked Ear - A dive into external auditory exostosis.

Numerous papers have reported the presence of reactive but benign bony exostosis in the external auditory canal of swimmers; of both cold and warm water. This outgrowth may lead to stenosis of the canal with associated complications such as repeated cerumen impaction, infections and also hearing loss. In this case report, we will present the case of a 62-year-old gentleman who was referred for imaging by an ENT specialist following difficulty with visualisation of the tympanic membrane during otoscopy.

Highlighting the classical MRI findings in transient global amnesia.

Transient global amnesia (TGA) is a disorder characterised by a temporary, reversible disruption of short-term memory. While the diagnosis of TGA is based on its clinical features, neuroimaging is important to exclude other sinister causes of global amnesia. Furthermore, classical MRI changes in TGA have been well described in the literature. These consist of unilateral or bilateral punctuate areas of hyperintensity in the hippocampal cornu ammonis 1 (CA1) region on diffusion-weighted imaging. We describe a case of a 61-year-old gentleman, presenting with symptoms of transient memory loss and confusion. A stroke was initially suspected in view of his multiple risk factors. Timely MRI demonstrated the typical findings associated with TGA. Recognition of these imaging features is of the utmost importance for radiologists in order to allow for an accurate diagnosis and differentiation from ischaemic pathology.

Case of primary hepatic leiomyosarcoma successfully treated with laparoscopic right hepatectomy.

We describe the case of a 77-year-old woman, presenting with non-specific epigastric pain. Physical examination and subsequent imaging revealed the presence of a large mass in the right liver lobe. This was shown to be a leiomyosarcoma on biopsy histology. Further investigation confirmed this to be a primary hepatic leiomyosarcoma with no evidence of metastases. The patient underwent successful surgical resection. She is currently under imaging follow-up, with no evidence of disease recurrence.

Solitary fibrous tumour of the mesentery: a case report.

We present the case of a male with an asymptomatic abdominal mass, where imaging-guided biopsy confirmed the lesion as a solitary fibrous tumour arising from the mesentery. This is a notably rare location for solitary fibrous tumours with only a few reported cases in the literature.

Highlighting an atypical cause of the Face of the Giant Panda sign.

The "Face of the Giant Panda" and the "Panda Cub" signs are neuroimaging features originally described in patients with Wilson's disease. We present a case with similar imaging findings in a different clinical context and highlight other differential diagnoses to be considered when presented with this particular radiological sign.