Understanding the role of immune activation and restoration in HIV infection A.G. Osborn; Salt Lake City, UT/US (anne.osborn@hsc.utah.edu) Immune reconstitution inflammatory syndrome (IRIS) occurs when restored immunity causes an abnormally robust response to infectious or noninfectious antigens. IRIS develops in 15-35% of AIDS patients beginning combination antiretroviral therapy (cART). IRIS develops in two distinct scenarios: "Unmasking" IRIS (u-IRIS) and "paradoxical" IRIS (p-IRIS). u-IRIS in AIDS occurs when beginning cART reveals a subclinical opportunistic infection against a living pathogen. p-IRIS occurs when a treated patient deteriorates after initiated of HAART. The recovering immune response targets persisting pathogen-derived antigens or self-antigens to cause tissue damage. This presentation discusses both types of IRIS and their imaging manifestations in the CNS. Neuro-IRIS affects only 1% of all IRIS cases but must be identified. u-IRIS should be distinguished from p-IRIS as disease management and prognosis differ significantly. PML-IRIS, TB-IRIS, fungal-and parasite-IRIS are illustrated. Non-HIV IRIS associated with natalizumab (Tysabri)-related PML will also be illustrated and insights into the roles of immune restoration in disease development in the setting of HIV-AIDS discussed. Since acquired immunodeficiency syndrome (AIDS) was first reported in the early 1980s, the lung was the organ most frequently affected by opportunistic lung infections (PCP) and noninfectious processes (Kaposi sarcoma and lymphoma). Since the beginning of the epidemic, more than 60 million people have contracted HIV and more than 25 million have died of AIDS-related causes. Actually, more than 33 million people live with HIV/AIDS and in 2009, 1.8 million people died from AIDS. The introduction of highly active antiretroviral therapy (HAART) has resulted in a considerable increase in the length of survival of HIV-infected patients. Although significant progress has been made in the past decade in the treatment Four randomised controlled trials (RCTs) comparing outcomes after carotid artery stenting (CAS) with carotid endarterectomy (CEA) have been published recently. Based on recent systematic reviews it has been recommended that CAS can no longer be justified for patients suitable for CEA. Indeed pooled data of the RCTs show higher peri-operative risk of performing CAS vs. CEA with comparable longterm efficacy in many centres. The inferiority of CAS to CEA as a method cannot be concluded from SPACE, EVA3S and ICSS because of limitations in study design and conduct. The goal of this presentation is not to discredit these trials but to develop a more differentiated and critical interpretation of the data and to create more discussion. I will discuss the necessity of randomised control trials (RCTs) for Interventional Neuroradiology in general and particular problems in study design (non-inferiority design and interpretation of results, clinical equipoise, study endpoints), practical study conduct difficulties (operator and centre experience, antiaggregation, timing of treatment) and the interpretation of the results (relation of internal and external validity, procedural complexity, the 68-years-surprise, longer-term outcome). A premature rejection of CAS based on the data from these studies could harm future patients who would have benefited from this procedure. The most common indication for PTA and stenting of extracranial arteries is atherosclerotic disease. Arterial dissection, spontaneous or traumatic, may also warrant such treatment. Other, less common, indications are Fibromuscular Dysplasia (FMD) and Takayasu´s arteritis (TA). Proximal stenosis of the internal carotid artery (ICA) is a common manifestation of atheroclerosis in the western world. It can be treated surgically with endarterectomy, but PTA/stenting has proven a good or better alternative for many patients as shown in recent multicentre randomised studies. It is today also possible in selected patients to reopen a completely occluded internal carotid artery. This may be a treatment option for patients with proven symptomatic hypoperfusion. Symptomatic atherosclerotic stenosis of the extracranial vertebral arteries (VA) is not as common, but PTA/stenting may be a treatment option also in this vascular territory. Arterial dissections usually heal but in a situation with haemodynamically significant impairment of flow, PTA/stenting may be needed in the acute situation. If the dissection causes a subarachnoidal haemorrhage, vessel sacrifice is often the safest treatment option. If that, however, for haemodynamic or other reasons is not possible, treatment with one or more stents may lead to a good outcome. When performing thrombectomy for acute stroke, a significant stenosis of the ipsilateral ICA or VA can be a complicating factor demanding procedural alterations including PTA/stenting. FMD may cause stenosis of the ICA, whereas TA predominately concerns the common carotid artery, both possible to treat with PTA/stenting if the patient suffers from thromboembolic or haemodynamic symptoms. Indications and contraindications of breast MRI will be discussed. Significant findings at breast MRI include foci (small contrastenhancing spot, NOS, < 5 mm), mass lesions, "non-mass-like enhancement" (no mass lesion, partly diffuse regional contrast enhancement of various size) and associated findings. As breast MRI is a functional study, different appearance patterns of kinetic contrast enhancement will be presented. The current status and the appropriate use of the BI-RADS MRI lexicon will be discussed. Any breast MRI report should not only follow these guidelines, but also express confidence, follow a red thread, be consistent and therefore be comprehensible for clinicians. The overall final BI-RADS assessment is based on the most worrisome finding, taking into account both breasts and all imaging methods (Mammography, Ultrasound, MRI) evaluated. Furthermore, adequate communication of the result as well as do's and don'ts of report wording will be discussed. MRI is more and more often used for PCa detection in patients with a negative series of biopsies and a persistent biological suspicion of PCa. Multiparametric MRI (mp-MRI) increases the accuracy of T2W-Imaging to localise PCa. The most widespread protocol includes dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DW-MRI) which improve accuracy of T2W-MRI to detect P-Zone cancers with a tumour volume > 0.2-0.5 cc. DCE-MRI has a high sensitivity but a limited specificity related to a common enhancement of benign P-Zone sextants and of T-Zone BPH nodules. On DW-MRI, PCa shows a significantly lower Apparent Diffusion Coefficient (ADC) value than that of benign prostate tissue which increases the specificity of T2W-MRI. Chronic prostatitis and BPH stromal nodules can have a low ADC value close to that of PCa, but the use of ultra-high b values (b2000) allows for a better differentiation between the three conditions. Significant differences in tumour ADC values are observed between patients with low risk, and those with higher risk localised P-Zone PCa. Image fusion between MR and TRUS data set is a promising tool to increase the accuracy of targeted TRUS guided biopsies. There is more and evidence that a normal MRI is correlated with absence of cancer or presence of an insignificant tumour. PSA level and mp-MRI may thus select patients requiring immediate biopsy to detect significant tumours and those in whom biopsy could be deferred and indicated if follow-up shows signs of PSA level progression and/or occurrence of suspicious MRI findings. The role of imaging in patients with increased PSA level after radical prostatectomy or radiation therapy, which are the two main curative treatment options for prostate cancer, is to aid in differentiating locally recurrent disease which can be managed with local therapy from distant metastatic disease requiring systemic therapy. Although the majority of local recurrences in post-surgical patients can be detected by MRI in the perianastomotic region which can also be evaluated with TRUS and TRUS-guided biopsy, some recurrences can occur at pelvic sites that are beyond the range of TRUS; MRI has a role of labelling these sites for TRUS-guided biopsy. The combination of an external phased-array coil and endorectal coil is recommended for detecting local recurrent cancer. Current protocols involve T2-weighted MRI combined with functional techniques like dynamic contrast-enhanced MRI (DCE-MRI), magnetic resonance spectroscopy and diffusion-weighted MRI. In the post-prostatectomy bed, recurrences present as lobulated masses having low to intermediate signal intensity on T2-weighted images and showing early, nodular enhancement with early washout of gadolinium on DCE-MRI. After radiotherapy early contrast enhancement and early wash-out is seen recurrent tumors whereas the enhancement of post-radiation fibrosis is slow and low, offering a good contrast with the usually hypervascular recurrent cancer. The overall diagnostic efficacy of conventional MRI in combination with functional techniques is better than T2-weighted MRI alone which may play an important role in better assessment of locally recurrent disease. During the past decade we have observed a growing interest in in-vivo imaging techniques for small animals. On the shadow of the successful application of dualmodality imaging in the clinical environment, such as combined PET-Computed Tomography (CT) or SPETC/CT, the hybrid imaging modalities have been recently transferred to small animal scanners. Nowadays, the possibility of easy integration of nuclear imaging techniques with other modality such as PET/SPECT/CT, PET/ MR or PET/Optical has become a mandatory requirement in the design of small animal imaging systems. The combination of different imaging modalities in the same scanner offers the possibility to perform experiments more effectively than with a single modality only. This is especially true when two modality scans are performed sequentially or simultaneously and without moving the animal. Present technologies for the construction of hybrid systems for small animals will be presented together with examples of commercially available hybrid scanners. Looking at the next future, small animal PET/MR seems to be one of the most appealing perfect choice for hybrid imaging, combining the exquisite sensitivity of PET with the morphological/functional/spectroscopic high-resolution imaging of MR. The present major limitation on the development of simultaneous PET/MR scanners is the non-insensitivity of PMTs to magnetic fields. A reliable solution could be the development of magnetic field insensitive position-sensitive photodetectors. A brief overview of the present status of development of the detector technology for PET/ MRI will be also presented. The purpose of this lecture is to discuss the most common indications to perform sinonasal CT scans, to provide an understanding of the most common disease states and their impact on the choice of the respective imaging protocol and to provide a checklist of what the radiologist needs to report. First, the basic concepts of sinonasal CT and cone beam CT imaging including current protocols, radiation doses, 2D and 3D reconstructions and administration of contrast material will be discussed, followed by a brief discussion of the pertinent anatomy including the most relevant radiological anatomical landmarks. A systematic review will include key radiological features of acute and chronic sinusitis and related complications, polyposis, mycetomas, allergic fungal sinusitis and sinonasal tumours. Major emphasis will be put on the systematic approach, on the bottleneck areas where occlusion of normal passages may occur, on CT findings necessitating an additional MR and on how to report in a comprehensive way. CT examination of the temporal bone: Temporal bone CT scans should be performed in a reproducible way. Axial reconstructions are made in the plane of the lateral semicircular canal and coronal reconstructions exactly perpendicular to this plane. Thin sliced images are postprocessed using high-resolution algorithms. MR examination of the temporal bone: the challenge is to perform a complete examination. The standard version of such an exam starts with axial T2-weighted images of the minimal invasive focal therapy (laser, cryo, HiFu), and MR-guided radiotherapy will be discussed. Examples will be shown. In 1996, Hasegawa et al. presented a prototype SPECT/CT-design comprising a clinical SPECT-camera in tandem with a clinical single-slice CT. The combined device was used to perform a small number of clinical studies, such as for quantitative estimation of radiation-dosimetry in brain cancer, whereby the CT data were used also to generate the SPECT attenuation-correction-factors (ACF). Since then, SPECT/CT has benefited a great deal from the advances in CT-technology and several commercial system designs are available today. The clinical adoption of SPECT/CT has been rapid, particularly for oncology and cardiology. SPECT/ CT currently has a smaller installed base than PET/CT. The proposal to combine PET with CT was made in the early 1990s by Townsend, Nutt et al. In addition to intrinsic image alignment, the anticipated benefit of PET/CT was to use the CTimages to derive the PET-ACF's. The first prototype-PET/CT became operational in 1998 and was clinically evaluated at the University of Pittsburgh. Since then PET/ CT-technology has grown rapidly by incorporating new concepts of PET, available as PET/CT only, and multi-slice CT. Today's installed base is about 5,000 systems worldwide. The improvement in accuracy of PET/CT compared with PET or CT for re-/staging is statistically significant and averages 10-15% over all cancers. Image artefacts inherent to SPECT/CT and PET/CT can be detected, interpreted and corrected/avoided by well-trained users. By adopting more innovative acquisition schemes and data processing SPECT/CT and PET/CT will become faster and more dose-efficient imaging methods and manifest themselves as integral parts of state-of-the-art patient management. Radiographers have a key role to play in the provision of high-quality forensic imaging services and indeed forensic radiography should be viewed as an area of specialisation within the broader profession in keeping with other specialist areas.