We have been among the first to exploit dendritic cell (DC) therapy to treat cancer patients. Over the past years, immunological responses are increasingly reported and clinical responses have consistently been observed. Moreover, DC therapy often has much milder side effects than standard chemotherapy. A major hurdle in the development of the DC therapy is accurate delivery of the cells to lymph nodes (LNs), or their successful migration from the site of injection to LNs. In particular, tools for measuring cell migration in vivo are necessary. Ideally, we would be able to quantify the number of DCs at the relevant site, with high resolution anatomical context to allow differentiation of LNs and the possibility of longitudinal data acquisition. Furthermore, functional data on the ensuing immune response is also required. Towards these ends, we have been working on developing imaging techniques to study DCs in vivo, for example with scintigraphy on 111In-labeled DCs, and magnetic resonance imaging (MRI) on iron-labeled DCs. Scintigraphy is quantitative, but it is restricted to the relatively short half-life of the radioisotope and is unable to resolve individual LNs. MRI allows high resolution anatomic localisation, but the use of contrast agents such as iron oxide is not quantitative. Our recent work has focused on imaging the functionality of these DCs using positron emission tomography (PET) to study LN activation. Finally, we have also developed in vitro assays that closely mimic in vivo DC migration in 3D scaffolds imaged using quantitative 19F MRI, as a substitute for in vivo optimization. We plan on applying Patient transport into the radiology department, contact to other potentially infectious persons, and things like breath-holding are reasonable burdens and dangers to immunocompromised patients. When searching the focus of fever, imaging should help to identify an affected organ system in order to eventually guide invasive procedures to identify underlying micro-organism or non-infectious disease. Equally relevant is the exclusion of its involvement with a reasonable specificity. Depending on local epidemiology, organ system, and the clinical signs and symptoms, suspected differential diagnosis can be derived from image patterns. Some of these diagnoses might be exclusion diagnosis; others might require invasive procedures including time-consuming and costly analysis to be verified. Invasive procedures, however, require adequate heostasis, which is usually not available for a substantial duration due to pancytopenia in patients which underwent chemotherapy. If imaging fails to derive the underlying disease confidently and conclusively in a fast way, clinicians might need to treat on an empirical basis. Empirical treatment plays a major role in immunocompromised or severely ill patients at risk, since mortality rises within hours of untreated disease. On the other hand, empiric treatment causes relevant toxicity and substantial costs, while imaging might become cost effective. The appropriate investigational technique, frequently targeted differential diagnosis, and the special needs of immunocompromised patients need to be understood by the referring physician as well as by the radiologist. Thus, an intensive interdisciplinary co-operation on a patient basis, as well as on a department basis is essential. Learning Objectives: 1. To learn more about the clinical conditions that cause fever without an apparent origin. 2. To be informed about the clinician's way of thinking in the process of differential diagnosis. Diagnosis of fever of unknown origin (FUO) is a major challenge for internists. The spectrum of disease includes infections (28%), inflammatory diseases (21%), malignancies (17%), and "no diagnosis" (19%). Deep vein thrombosis (3%) and temporal arteritis in the elderly (16%-17%) are important considerations. Investigation of patients with FUO usually includes clinical and standard biological tests which give numerous clues. Imaging procedures depend on objectives and various imaging investigations should be organised in strategies. Early identification of the best tissue to be the site of biopsy is one of the most decisive procedures. First-line imaging studies usually include chest radiography, abdomen ultrasonography, and contrast-enhanced CT of the thorax abdomen pelvis in order to disclose common aetiologies such as infections ( Chronic pancreatitis (CP) is a continuing inflammatory process, characterised by irreversible morphological changes, pain and permanent loss of exocrine/endocrine function. Patients with suspected CP will undergo imaging and/or pancreatic function tests to rule out early CP. Standard MR protocols consist of: axial/coronal TSE T2-w, fat-suppression axial GRE T1-w and axial/coronal MRCP sequences. Early ductal changes, as ectatic secondary ducts (pathognomonic sign of early CP) may not be detected on standard MRCP. Secretin-enhanced MRCP (S-MRCP) studies, performed during exogenous secretin stimulation, increase the diagnostic accuracy in patients with suspicion of CP. The physiologic effect of secretin, i.e. transient increase of pancreatic exocrine juice in the ductal system, improves pancreatic duct visualisation on MRCP images. S-MRCP can quantitatively estimate pancreatic exocrine reserve. Significant differences were reported between normal and severe CP, while values obtained in mild CP were in the same range of normal. Normal pancreatic parenchyma appears bright on unenhanced fat-suppressed GRE T1-w images due to high protein content in the acini. On contrast-enhanced GRE T1-w studies normal pancreas enhances significantly on the arterial phase due to its rich arterial network. Parenchymal changes in CP patients are characterised by loss of normal functional parenchyma and vascularity, replaced by fibrosis. These changes induce the loss of pancreatic parenchyma hyper-intensity on unenhanced GRE T1-w images and delayed arterial enhancement on contrast-enhanced images. Recent published studies reported significant differences of apparent diffusion coefficients (ADCs) calculated at baseline and after secretin stimulation between normal and CP, with no differences among the different degree of severity. Sunday modalities of choice after renal transplantation. MSCT and MRI are valuable when these techniques are inconclusive or when post transplantation complications are suspicious. Renal transplant complications may result in impaired renal function or graft loss, most occurring at predictable times post transplantation. Post transplant complications can be divided into four major categories: parenchymal abnormalities, collecting system abnormalities, perinephric collections, and vascular abnormalities. Main vascular complications are renal artery stenosis/thrombosis, renal vein stenosis/thrombosis, arteriovenous fistula and pseudoaneurysm. Parenchymal complications are acute tubular necrosis, acute and chronic rejection, infarct, pyelonephritis, renal cell carcinoma and post transplant lymphoproliferative disorder. Perinephric collections are urinoma, haematoma, lymphocele and abscess. Main collecting system complications are hydronephrosis, calculi, urinary leak and obstruction. DUS is excellent tool not only to assess anatomic abnormalities and vascular status, but also to establish a baseline for future follow-up. Radionuclide scans help to assess renal perfusion and function. CT or MR urography allows imaging of the entire course of ureteral and periureteral abnormalities. US and CT are very useful for guidance of renal biopsy and drainage of large fluid collections. CT or MR angiography may be useful in doubtful cases to evaluate renal artery stenosis. Treatment of choice in diagnosis of the renal artery stenosis is percutaneous transluminal renal angioplasty (PTRA) or PTRA with stent. Learning Objectives: