1. To learn about useful and applicable imaging techniques, including their specific adaptations and the needs when applied in infants and children. 2. To become familiar with the respective imaging algorithms in applicable typical childhood scenarios. 3. To become familiar with the common imaging findings and their differential diagnoses and common pitfalls. The vomiting child can present the paediatrician and paediatric radiologist with a difficult diagnostic problem. As discussed in the previous lectures the differential diagnosis is based on age specific diseases. Both gastrointestinal as non-gastrointestinal diseases of childhood can cause vomiting in a child. During this interactive session a broad range of cases, the usual and unusual, will be presented. Each case will be introduced by a short summary of the clinical information. The question will not only be which diseases should be included in the differential diagnosis but also which imaging modality and protocol should be used in this case. The importance of choosing the correct imaging technique and protocol is of importance not only from a perspective of patient satisfaction but even more from an ALARA point of view. In paediatric radiology avoiding unnecessary (repeat) exams and choosing the right technique and protocol has the biggest impact on radiation reduction. Paraparesis is clinically defined as a weakness of the lower extremities. It is usually caused by an injury of the spinal cord in the thoracic, lumbar or sacral part of the spine or by toxic effects. An acute onset is a neurologic emergency, which requires an immediate clarification -mainly by an imaging study. There are several conditions in oncology that may cause an acute paraparesis. These include acute myelogenous leukaemia, metastasis, Hodkin´s disease, lymphomatosis meningitis, cervical or lumbar spinal cord tumour or metastasis, multiple myeloma, primary myelofibrosis/ myeloid metaplasia or metabolic and treatment-associated changes in the spinal cord. As the paraparesis starts in this context without a traumatic background, MR imaging is the method of choice in the workup of these patients. In this overview we will classify and describe the different oncologic conditions which may cause an acute paraparesis and highlight typical imaging findings in both intramedullary and extramedullary causes. Whilst the pathways for the detection and staging of lung cancer are well known, the use of imaging for the detection of disease relapse are less well established. Detection of relapse is now more complex, due to the use of multimodality therapy, including surgery, radiotherapy, chemotherapy and new ablative techniques. Each of these therapies may affect the site and appearance of recurrent disease. Additionally new techniques such as PET-CT and diffusion-weighted imaging have not yet been fully evaluated in this context. This presentation will focus on the timing of repeat imaging post treatment, the features of recurrent disease and suggest follow-up protocols, paying particular attention to imaging in the context of retreatment of disease relapse. Vomiting is a common symptom in childhood and can be caused by numerous conditions. In children we not only face difficulties in defining the conditions that may cause vomiting but also in differentiating true vomiting from physiological regurgitation, especially in younger children. In this session the clinico-radiological approach to a vomiting child will be discussed and illustrated by different clinical scenarios. This session will focus on the most common age-specific entities that may cause vomiting and how the approach to imaging in a vomiting child differs from in adults. It emphasises the importance of a good collaboration between the paediatrician and the radiologist to improve the diagnostic pathway. In detail, a multi-disciplinary approach is needed to avoid unnecessary diagnostic tests. The role of imaging not only in establishing the final diagnosis, but also in excluding underlying conditions that may need intervention will be discussed. This paper reviews the use of imaging techniques for the assessment of the vomiting infant and child. The differential diagnostic workup for the common clinical presentations of vomiting in the different age groups will be described and illustrated for age-specific diseases. Nausea and vomiting are common sequelae of multitude of disorders that can range from mild, self-limited illness to severe, life-threatening conditions. Bilious vomiting in the newborn is considered a radiological emergency and requires quick and exact diagnosis, whereas vomiting in children often is associated with gastroenteritis which not requires any imaging. In neonates with bilious vomiting, the first step in the imaging evaluation is the abdominal plain film which may reveal evidence of upper gastrointestinal tract obstruction. Direct imaging of the stomach and small bowel using the upper contrast gastrointestinal series or fluid-aided ultrasound answers the question if there is a mechanical obstruction. X-ray contrast enema may play a role in the evaluation of suspected malrotation The simple answer to this question is "yes" for most situations: and notably when surgery is not planned. The complicated answer is that US relying on morphologybased systems supplemented by Doppler evaluation cannot reliably provide the information used to direct women with a complex ovarian mass to appropriate surgery unless there are clear secondary signs of disseminated malignancy. The difficulty is in deciding when to use CT or MR imaging after US. That is the topic to be discussed in the context of new ESUR guidelines. Most women diagnosed with endometrial cancer are postmenopausal (~25% are premenopausal). Endovaginal ultrasound is widely used for initial assessment in menopausal patients, especially if bleeding is present. Measurement of the thickness of the endometrial stripe can help determine the need for D&C. After diagnosis, MRI is the best imaging modality for locoregional staging and detecting recurrence (preliminary data suggest FDG-PET may also be useful for follow-up). Surgery remains the primary treatment modality, but radiotherapy and chemotherapy are being used for advanced disease and patients at high risk of recurrence. In 2009, FIGO staging guidelines were revised. MRI is especially helpful for distinguishing stage IA from stage IB (≥ 50% myometrial invasion), which is associated with a 40% incidence of lymph node metastasis and a need for lymph node dissection and for identifying stage II (invasion of the cervical stroma, calling for radical hysterectomy). While pretreatment knowledge of these findings is helpful, cost-effectiveness studies are lacking, and routine use of MRI is controversial. MRI should include at least two T2-weighted sequences showing the short and long axes of the uterus (sagittal, axial oblique or coronal oblique). High-resolution imaging 2 min ± 30 s post-contrast injection is optimal for diagnosing myometrial invasion. If cervical invasion is suspected, an additional slice perpendicular to the endocervical channel is recommended. Pre-contrast sequences up the renal hilum enable retroperitoneal lymph node screening. Indications for MRI include high-grade, serous or clear-cell adenocarcinoma; suspicion of stage ≥IB; detection of enlarged nodes for sampling; inability to perform D&C or surgical staging. Posterior reversible encephalopathy syndrome (PRES) is characterised by headache, altered mental status, visual disturbances and seizures. Different conditions have been associated with PRES, such as for example eclampsia bone marrow transplantation and immunosuppressive treatment, hypertension, autoimmune disease and cancer chemotherapy. The pathophysiology of PRES is still unclear and different hypothesis will be discussed in this lecture. Typical radiological imaging findings which are best presented on MRI include signal abnormalities due to vasogenic oedema in predominately but not only white matter of the posterior regions of the cerebral hemispheres, like the occipital and posterior parietal lobes but also the frontal lobes often involved, whereas the cerebellum, the brainstem, the deep white matter and basal ganglia are more atypical locations. The incidence of radiation necrosis ranges from 5 to 24%. The delayed neurological symptoms include functional and cognitive impairments, including deficits in learning, working memory, executive function, vision, and motor function, and eventually dementia. A complete understanding of the pathophysiology of radiation therapy-induced changes to the central nervous system (CNS) is still lacking. MRI cannot reliably discriminate tumour recurrence/progression from the inflammatory or necrotic changes resulting from radiation, although the latter can be associated with more specific patterns of enhancement, such as "soap bubble"-or "Swiss cheese"-like with or without feathery margins and central necrosis. This lecture will focus on the pathophysiology, aetiology and imaging features, of PRES and radiation necrosis and their differential diagnosis in oncology patients. Percutaneous image-guided procedures can be applied for tumour management in cases of spinal tumours. They consist of the tumour ablation and/or vertebral consolidation. These procedures are usually not considered as acute emergency. However, in cases of impending vertebral collapse, spinal consolidation should be performed on an emergent basis. For the palliative treatment of painful spinal tumours (metastases), the therapeutic goal should not be the complete ablation of the tumour, but one or more of the following: tumour reduction, pain management, prevention of risk of pathological fractures and in some cases, decompression of spinal tumours extending towards the spinal canal. Precise clinical evaluation of the patient is mandatory: origin and location of pain, previous treatment, which anaesthesia the patient can tolerate, and life expectancy. For tumours causing any neurological signs, surgical decompression should be the first treatment option. Multidisciplinary decision is required to choose the more efficient and less disabling technique. To evaluate postsurgical patients it is important to know the primary clinical diagnosis, the surgical treatment, the interval since surgery and patients' current clinical symptoms. Radiography is the most common imaging modality to evaluate the postoperative ankle, particularly in traumatic cases; after reduction and fixation of a fracture or dislocation it is generally carried out as routine. Ultrasonography is highly sensitive and specific in postoperative tendon assessment, thanks to the superb resolution, and the opportunity for dynamic evaluation of tendon integrity. MRI has rapidly become important in post-operative assessment of the ankle, because it provides high soft-tissue contrast, multiplanar capability and osseous structures visualisation. It shows signal changes of ligaments and tendons, hypointense subchondral sclerosis, subchondral bone marrow oedema, joint effusion, capsular thickening, fibrosis and synovitis. MRI has also an important role in the evaluation of post-surgery ankle pain due to impingement syndrome and in the hindfoot chronic instability related to postoperated sinus tarsi syndrome; it demonstrates the anatomy of sinus tarsi, chronic synovitis and nonspecific inflammatory changes, synovial cysts, fibrosis and subtalar joint effusion. It is important also in the follow-up of tumours and tumour-like conditions of bone and soft tissues after surgery. Computed tomography is the most valuable method to define the osseous anatomy of the postoperative ankle, so it is important in the follow-up of the operated osteochondral lesions of the talus. CT allows the evaluation of irregularities or degenerative changes and progressive degenerative arthritis; however, CT usually fails to evaluate soft tissue ankle lesion. There are many surgical techniques to repair meniscal tear: focal cartilage defect, cruciate ligament tear, malalignment, fracture, osteoarthrosis,… Conventional radiography, CT-scan, CT-arthrography and MRI play an important role in evaluation of the knee after surgery or arthroscopy. Indications for postoperative imaging are infection, persistent pain and dysfunction. Every radiologist should be familiar with "normal" imaging findings after arthroscopy, osteosynthesis, ligament reconstruction, osteotomy, knee prosthesis and meniscal or (osteo)chondral repair, but also recognise the main complications after knee surgery or arthroscopy. Orthopaedic hardware is usually evaluated on plain radiography or CT, and only a relative contraindication for MRI. Microscopic metal artefacts and fibrotic scarring are frequently seen along the course of the instrumentation tract. After partial meniscectomy, an obtuse angle at the apex of the meniscus and increased signal intensity of the remnant part of the meniscus are normal findings, whereas fibrillation and recurrent tear may explain complaints of the patient. Various intra-and extra-articular reconstructive procedures exist for anterior and posterior cruciate ligament reconstruction. Besides the neoligament, an osseous tunnel, screws and metal artefacts are also visible. Postoperative findings of the extensor apparatus include a thickened patellartendon, focal myxoid degeneration, fibrosis and focal defects, e.g. after harvesting tendon tissue for ACL reconstruction or after release of the lateral patellar retinaculum for 'unstable' patella. Accelerated osteoarthritis may be a late postoperative finding. MRI very well depicts incorporation and alignment of osteochondral auto-or allografts, and the position, morphology and integrity of the meniscus after repair or transplantation. Even if the RECIST criteria based on anatomic size measurements of the tumours have been recently updated, difficulties are still often encountered in measuring lesions, both in primary tumours and metastases. The aim of this course is to analyse the major causes of these difficulties. Some are due to the tumours themselves, known to be a constant problem in assessing their response to treatment. Bone lesions for example are even considered non target lesion leading to a non-eligibility of the patients for a new therapy and the absence of correctly measurable disease in malignant pleural mesothelioma or ovarian cancer can affect patient management. Evolution under treatment of some tumours (even if they are easily evaluable before treatment) and /or the adjacent parenchyma may also be the cause of difficulties in assessing response. Modality used in the study, use of automated measurements, type of study and type of treatment (GISTS) may affect the measurements. The different criteria of response may also lead to discrepancies between observers. Panel reviews often offer the opportunity to realise how much intra-observer variability is important in these particular tumours. The second part of this course consists in searching either in our experience or in the literature, the new avenues to improve the quality of assessment of response in these kinds of tumours known as "difficult" and even to look forward to using new criteria, new techniques and also new endpoints The mainstay for image evaluation of response to oncological therapy is CT or MRI applying morphological criteria, generally RECIST, or in recent clinical trials RECIST 1.1. For some tumour types these criteria are not applicable and for others RECIST-like criteria have been developed depending on the specific characteristics of the tumour type. One example is the so-called Choi criteria for GIST that relies not only on changes in tumour size but also on alterations in lesion attenuation.