DW-MRI performed both at baseline and mid-course of neoadjuvant chemotherapy is an efficient method to predict further histological response of osteosarcoma. This method could be used as an early prognostic factor to monitor preoperative chemotherapy.

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The different factors involved in the choice of the best cardiovascular imaging examination for pediatric patients are justification, radiation protection, sedation, resolutions (spatial and contrast), morphology or function, intervention and contrast enhancement. Computed tomography is preferable for all coronary artery conditions, any arterial or venous abnormalities in newborns and infants and in the preoperative assessment for tetralogy of Fallot. Magnetic resonance imaging is used for any tumoral or functional assessment, cardiomyopathy or arrhythmia or if the child's participation and/or size of the structures being examined allows using this technique.

Levamisole (an increasingly frequent contaminant of cocaine) can cause antineutrophil cytoplasmic antibody-associated vasculitis. Dermatologists should consider a diagnosis of cocaine/levamisole-associated cutaneous vasculopathy syndrome in cases of purpura of the ears and/or extensive retiform purpura in drug users. We report a case of particularly severe levamisole-induced necrotic purpura and immunological abnormalities in a 40-year-old woman.

Background Diffusion-weighted imaging (DWI) has been described to correlate with tumoural necrosis in response to preoperative chemotherapy for osteosarcoma. Objective To assess the accuracy of DWI in evaluating the response to neoadjuvant chemotherapy at the mid-course treatment of long-bone osteosarcoma and in predicting survival. Materials and methods We conducted a prospective single-centre study over a continuous period of 11 years. Consecutive patients younger than 20 years treated with a neoadjuvant regimen for peripheral conventional osteosarcoma were eligible for inclusion. Magnetic resonance imaging (MRI) with DWI was performed at diagnosis, and mid- and end-course chemotherapy with mean apparent diffusion coefficients (ADC) calculated at each time point. A percentage less than or equal to 10% of the viable residual tissue at the histological analysis of the surgical specimen was defined as a good responder to chemotherapy. Survival comparisons were calculated using the Kaplan-Meier method. Uni- and multivariate analyses with ADC change were performed by Cox modelling. This is an expansion and update of our previous work. Results Twenty-six patients between the ages of 4.8 and 19.6 years were included, of whom 14 were good responders. At mid-course chemotherapy, good responders had significantly higher mean ADC values (P=0.046) and a higher increase in ADC (P=0.015) than poor responders. The ADC change from diagnosis to mid-course MRI did not appear to be a prognosticator of survival and did not impact survival rates of both groups. Conclusion DWI at mid-course preoperative chemotherapy for osteosarcoma should be considered to evaluate the degree of histological necrosis and to predict survival. The anticipation of a response to neoadjuvant treatment by DWI may have potential implications on preoperative management.