1. To know about perfusion imaging protocols, specific advantages and technical challenges. Apart from morphology and perfusion characterisitcs, the evaluation of tumor agressiveness is closely related to other components of the tumor biology. Some of these "tumor variables" can be measured by the use of imaging biomarkers of tumour activity and phenotype. Imaging biomarkers are objectively measured characteristics that can be used as indicators of tumour biopathological changes. By using the qualitative and quantitative information of the different imaging modalities (US, CT, MR, PET) imaging specialists may be able to predict tumor prognosis and define the most appropriate therapeutic strategies. In this talk the most relevant components (cell density, cell and vascular heterogeneity, tissular entropy, tumor metabolites, cellular receptors, intracellular and interstitial physiological changes, pH, oxygen and iron concentration, elastic properties, physical quantities as the T1 and T2 relaxation times and biochemical molecular expresions) will be commented together with the different ways to explore them thought imaging parametric and multiparametric maps. These graphic maps characterice imaging biomarkers in two ways. First, they represent quantitative variables that characterize and measure different parameters obtained from medical images that are relevant to the tumour grading. Second, parametric images allow us to analyze the spatial distribution of the biomarker in the tumor through its visual representation. These images are generated to provide a graphical representation of the values of the calculated parameters on the basis of original image by post-processing computing. The use of imaging biomarkers in information-driven decision-making in clinical trials and oncologic clinical care will be simplified and supported through computer-aided diagnosis/quantitative image analysis. Imaging investigation of cholesteatoma is required before surgery. If no surgery has been performed previously, CT will provide information about the location of the lesion (epi, pro, meso, retro, hypotympanum), the partial or total destruction of the ossicles and possible extension to the inner ear. If there is no doubt about any of these factors CT is sufficient. In doubtful cases an MRI examination is performed to confirm or refute the presence of cholesteatoma using T1 sequences without IV contrast medium, and diffusion-weighted imaging with or without high-resolution T2, depending on the age of the patient. In postoperative recurrent cholesteatoma, MRI is becoming the first choice modality for detecting cholesteatomas, appearing low in signal on T1 sequences and high in signal on diffusion-weighted imaging. However, care is required since performing diffusion-weighted imaging without T1 may lead to false positives. A granuloma with a slightly or markedly increased T1 signal is often associated with a high signal on diffusion. Measurement of ADC is useful for detecting cholesteatomas, infected cholesteatomas or abscess. Finally, whilst MRI is the first examination in the follow-up of postoperative patients, the use of contrast medium is not necessary in most of the cases. Inner ear enhancement can only be seen in a reliable way on gadolinium-enhanced MR images. High field MR even allows inner ear screening with sub-millimetric contrast-enhanced T1-weighted images. On these images one can distinguish whether the enhancement is in the scala tympani or scala vestibule of the cochlea. The most frequent causes of inner ear enhancement are intralabyrinthine schwannoma (ILS) and labyrinthitis. Labyrinthitis can be viral, bacterial, autoimmune and luetic. Moderate to strong enhancement will only be seen in the acute phase and when the labyrinthitis is causing an important enough blood-labyrinth barrier rupture. Most often both the cochlea and the vestibular system are involved and the edges of the enhancement are unsharp. Under treatment this enhancement gets weaker and will finally disappear. Schwannomas have a stronger enhancement, the enhancement is better delineated, the lesions are most often restricted to the cochlea or the vestibular labyrinth and they can grow over time. When they grow they follow the pre-existing intralabyrinthine anatomical pathways. Many other less frequent lesions like meningiomas, granulomatous diseases (e.g. tuberculosis), trauma-surgery, cholesteatoma, etc., can also affect the inner ear and cause inner ear enhancement. The most frequent causes of inner ear enhancement, their MR characteristics and their natural behaviour will be discussed in this lecture. This session will provide the participants with a practical update on the principal indications to pediatric neuroimaging with a discussion of the main study techniques. The first presentation deals with the indications for ultrasound in neonates, where the advantages compared to MRI will be elucidated. The second presentation focuses on the applications of MRI in the study of normal brain development both before and after birth with an emphasis on how to correctly report an MRI study and the main pitfalls in children. The third presentation focuses on advanced MRI A-015 17 Acute stroke is increasingly being treated by neurointerventional techniques. Intra-arterial recanalisation provides better recanalisation rates and potentially better outcome for large vessel occlusion as compared with systemic thrombolysis.