of the local tumour response, but also be extended to an accurate evaluation of the nodal response. The objective of this lecture is to understand the increasingly important role of radiologists for stratifying rectal cancer patients, not only before but also after preoperative treatment. It will discuss the evidence for organ saving new treatment options and how this evolution will influence our diagnostic decisionmaking process. It will elucidate the (limited) role of present imaging and point at potential future techniques (diffusion and perfusion MRI, lymph node-specific contrast-enhanced MRI, PET/CT) for the precise selection of patients. Identification of (a)symptomatic individuals at high risk of myocardial infarction is important to optimise treatment and prevent a coronary event. However, optimal patient selection remains a challenge, even after evaluation of cardiovascular risk factors. The coronary calcium score, derived from newer CT generations (at least 16-MDCT), accurately reflects the amount of coronary atherosclerosis and can improve cardiovascular risk assessment. In this presentation, results from recent prospective population-based studies will be discussed, including the Heinz Nixdorf Study, Multi-Ethnic Study of Atherosclerosis and Rotterdam study. These asymptomatic, general populations consistently show strong predictive value of calcium However, there are caveats as it uses the strong static magnetic field, transmitted radiofrequency and time-varying gradients fields. These can affect instrumentation including projectile attraction and/or twisting of tools to align with magnetic field and operational interference. Hence the MRI interventional suite requires care and the use of specialised non-magnetic instruments (e.g. Titanium tools). Interventional MRI also requires staff to stay in the scanning room during imaging which presents a range of safety issues that will be discussed. Access to the patient is also a consideration; options include using an open bore scanner or having a surgical suite where the patient can be moved on a sliding patient table between the MRI scanner and another one for access. Does improved technology lead to better outcome in vascular interventions? In some cases it does, but most of the time we just have no idea and we all follow the delusion of the day. Maybe the European notified bodies should start to handle registration of new medical devices and implants in the same way as they do with new drugs. This would be a great stimulus for good research, better patient care and most likely a reduction in medical treatment related costs. More than 90% of the new devices will never reach a more than a 3-4 level of evidence. Single arm and single centre studies, often underpowered and with a dubious methodology, presented at medical meetings or published in second class journals, that is main stream in new technologies for vascular medical devices, and probably this is also true for other specialities in medicine. Who are the main stakeholders in this game? The patients, who will be treated with a device without any proof of efficacy or superiority compared to standard treatment. The doctors who like new technology (gadgets). The health care providers, who will have to pay for expensive non-proven technology. The manufacturers who want a good return of investment for their shareholders. The weakness of the current regulatory will be discussed. Traditionally, interventional procedures, such as coronary interventions or orthopedic procedures, were guided using simple x-ray fluoroscopy, which delivers two-dimensional radiographic images as a function of time. During the past decade these c-arm systems became capable of acquiring tomographic information. This so-called rotational angiography or interventional cone-beam CT has found rapid application in the catheterisation laboratories and in the operating rooms. Today, many interventional procedures rely on the tomographic information taken before, during or after the intervention. While standard tomographic c-arm devices are equipped with cost-efficient image intensifiers the high-end systems use the flat detector technology, which is more compact and not prone to distortions. Compared with clinical CT rotational angiography allows for a far better patient access, provides images of higher spatial resolution, but suffers from the lack of low-contrast resolution and from low temporal resolution. The main reason for these differences is the During the presentation, technical aspects and clinical indications for all imaging modalities will be reviewed. The development of imaging modalities now allows scanning large body volumes in a very short time, necessary to obtain pure vascular phases. In particular, scanning of the extracranial and intracranial carotid arteries should be performed in less than 10 seconds, to avoid filling of jugular veins and image degradation. Either with computed tomography or magnetic resonance, such a short scanning is feasible, maintaining an excellent spatial resolution that allows detection of even minimal parietal irregularities. By performing such exams, it is possible not only to assess the patency of the vessels and demonstrate the degree of stenosis or the presence of aneurysms, but also to evaluate the characteristics of atherosclerotic plaque, which is also important for treatment planning. In this setting, magnetic resonance may provide some advantages over computed tomography, either exploiting its high intrinsic contrast or by using intravascular or high relaxivity contrast agents, which allow acquisition not only during the first pass, but also in the steady state. In particular during the steady state, it is possible to acquire high-resolution images with the result of increasing the detectability of small parietal ulcerations and wall irregularities. Magnetic resonance is generally preferred also when dynamic imaging is required, especially when malformations and/or fistulas need to be evaluated. Interpretation of bedside chest radiograph is particularly difficult, because only one antero-posterior view is available in patients with severe illness and sub-optimal breath-holding. The storage phosphore-based computed radiography system is frequently used in this clinical setting and provides several advantages: for example, compensation for variations in exposure and decreased radiation to the patient with a better image quality. Technical requirements are important to know because the bedside chest radiography has to be reported using optimal conditions: patient upright or in a semi-erect position at deep inspiration with a target-to-film distance of approximately 130 cm. In ICU, technical parameters are often limited with the patient supine and a shorter focus-film distance. Consistency in technique and positioning is critical for optimal evaluation of the patient on serial examinations, and technical parameters have to be transmitted between technicians in order to reproduce the same conditions. Careful plain film analysis begins with systematic control of the technical quality, followed by a careful analysis of external devices, chest tubes and catheters. Potential kinking and aberrant positions must be reported. Systematic comparison between both lungs will help the radiologist to discover abnormal findings. Repartition of air and fluid is different on bedside chest radiography and knowledge of their appearance is essential. Differential diagnosis of radiological patterns is often difficult and will be confronted with the clinical information. In many situations, a side-by-side comparison between standard radiography and CT will be performed to better understand the imaging findings, discover the main pitfalls and help the radiologist for eventual reinterpretation. Current multi-slice spiral computed tomography (MSCT) allows for a robust examination of the entire chest with submillimeter collimated protocols in a single breathhold. This is the basis for dedicated analysis of the thoracic vasculature, especially in an interactive setting, for instance using curved multiplanar reformats (cMPR). CT angiography (CTA) is mainly used for clinical suspicion of acute pulmonary embolism (PE), and for the assessment of acute and chronic aortic disease. With ECG synchronisation of the data set, a complete assessment of the cardiothoracic vasculature can be achieved, including the coronary arteries. Iodine mapping (depicting the segmental defects in iodine distribution in locations corresponding to embolic vessel occlusions) has become technically feasible in PE, e.g. using dual energy acquisition protocols. This might further improve detection of emboli and give insights into the effects on perfusion deficits in the adjacent lung parenchyma. In addition, an overview on the current status on computer-aided diagnosis software for the semi-automated assessment of PE will be provided. Image-guided percutaneous abscess drainage is one of the most common interventional procedures performed today. It can provide definitive treatment of most collections in the chest, abdomen, pelvis and, selectively, other body parts, thus obviating surgical exploration. The most critical step in performing percutaneous abscess drainage is selection of the imaging modality and selecting the appropriate access route. Uncorrectable coagulopathy and lack of a safe route for catheter placement, most commonly due to interposed bowel loops, are contraindications to the procedure. Local anaesthesia or light sedation is usually employed. Children and uncooperative patients may need general anaesthesia. The shortest pathway between the skin entry point and the abscess is usually chosen. Tandem-trocar technique, Seldinger technique and direct trocar catheter placement are the most common catheter insertion methods. The catheter sizes used range from 8 to 24 Fr and most have an inner retention mechanism. The drainage catheter is secured to the skin after placement and the abscess is completely evacuated while the patient is in the x-ray department. The catheter is then left to gravity drainage connected to a collection bag. Occasionally, if catheter placement is not feasible, needle aspiration may be safe and effective. The catheter is checked on a daily basis and irrigated with 5-10 mL of normal saline to maintain patency. Intracranial atherosclerosis is a systemic and multifactorial disease, associated with atherosclerosis of carotids, coronaries, aorta, renal and iliofemoral arteries. Over one third of ischemic strokes occur in the posterior circulation, a leading cause of which is atherosclerotic vertebrobasilar (VB) disease. Symptomatic VB disease carries a high annual risk of recurrent stroke, averaging 10-15% per year, despite medical therapy. VB stroke is particularly prone to devastating consequences due to the eloquence of the regional brain tissue and is associated with high rates of death and disability. More common in older age and in Western countries, without differences of gender. CTA and/or MRA are excellent screening tool, but DSA is the gold standard to show focal stenosis, luminal irregularities, thrombosis, occlusion, arteries ectasia and elongation, serpentine aneurysms. Transient ischemic attack, along with severe stenosis and progressive occlusion, are most common symptoms. An important stroke mechanism in VB atherostenosis is regional hypoperfusion. Furthermore, both embolic and flow processes can synergize to increase stroke risk, reducing the wash-out of emboli from the distal circulation in hypoperfused regions. Posterior circulation collateral channels may maintain adequate distal flow. The existence and extent of these compensatory blood flow pathways, evaluated by DSA, may influence the risk of stroke. Percutaneous angioplasty and stenting for symptomatic atherosclerotic VB stenosis is a feasible and effective therapeutic method, but good experience and full understanding of neurology and hemodynamics are required. Cross sectional MRI demonstrates the vessel wall and intramural hematoma. MR and CT perfusion imaging are useful to assess the hemodynamic effects of dissections. Cerebral vasculitis can affect the large (proximal intracranial) vessels, medium-sized vessels (distal to the MCA bifurcation) and small vessels < 300 μm. Cerebral vasculitis can occur as primary angiitis of the CNS, as complication of a systemic vasculitis (Takayashu's, Poloyartitis nodosa), as secondary vasculitis in connective tissue disorders (SLE, rheumatoid arthritis and Behçet's), infections (tuberculosis, aspergillosis, varicella, HIV, borreliosis), and drug use (cocaine, heroin). CTA and MRA can demonstrate involvement of large and medium sized vessels. Invasive cerebral angiography has the best spatial resolution but carries a procedural risk and is still unable to detect involvement of small vessels (< 300 μm). The latter is diagnosed by the effects on the brain parenchyma on MRI (infarcts, microhaemorrhages) and local hypoperfusion on MR perfusion studies. Whilst MRI is highly sensitive to detect changes in cerebral vasculitis, its specificity is relatively low and brain biopsy is frequently required to make a definitive diagnosis of cerebral vasculitis. neuroimaging studies. Despite these advantages, operating at such field intensity raises technical challenges. First, pulse sequence design and implementation must take into account specific characteristics of MR physics at high-field strength (increased T1 and decreased T2 relaxation times, increased chemical shift or B0and B1-related inhomogeneities). For this reason, merely transposing imaging sequence protocols that are effective at lower fields is not sufficient, because there are particular theoretical issues. Second, there are several artefacts and drawbacks resulting from some of these physical events, such as magnetic susceptibilityinduced artefacts (resulting in signal misregistration and intravoxel dephasing), compromised fat suppression (specially on air-tissue or air-bone interfaces) or image B1-induced dielectric effects on abdominal imaging. Other types of artefacts such as patient (in)voluntary motion, CSF pulsation, blood flow or Gibbs are also present at lower-field strength; there are nevertheless variations that are more misleading and appear frequently and in a more severe way at high-field strength.