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Time for Safety ulrich medical® Contrast Media Injectors www.ulrichmedical.com Europ_Hospital_103x133mm_R1-0.indd 1 14.10.2015 14:24:51 EUROPEAN HOSPITAL  Vol 24 Issue 5/15 16 RADIOLOGY Vasculitis in the brain Benefits for young patients - ‘Especially for younger patients who, measured by their age, present with too many micro-angiopathic changes in the brain, it makes sense to carry out further investigations into the presence of vasculitis with additional MRI sequencing,’ Gizewski advises. As some patients do not even notice such micro-infarctions and are not admitted to hospital, but present as out-patients or in GP surgeries, it is particularly important to use this technology for clarification of a diagnosis. ‘The additional sequence probably takes about eight minutes,’ the neu- roradiologist explains. ‘When vas- culitis is suspected, the diagnosti- cian should therefore examine the respective areas in the brain before and after administration of a contrast agent.’ Vessel wall imaging for smaller vessels Vasculitis does not lead to the com- plete occlusion of the vessels that occurs in large infarctions, but to an inflammation of the vessel walls. Previously, the diagnosis was diffi- cult to confirm, because of available technology limitations; it required the more invasive catheter angi- ography, along with clinical and laboratory tests. ‘An important dif- ferential diagnosis is required to clarify whether the patient has had an embolic stroke, or whether they are suffering vasculitis,’ Gizewski points out. ‘In principle, the procedure works like vessel wall imaging; however, we don’t look at the large vessels, such as the aorta, but at the, in parts, very small vessels in the brain. In neuroradiology the procedure is still carried out comparatively infre- quently and currently requires fur- ther evaluation.’ Contrast agents help to determine those affected The administration of contrast agents enables confirmation of changes to the vessel walls, which indicate an inflammation. If only the right side of the brain is affected, the vessel walls on the right side will accumu- late the contrast agent; those on the left will not. Thus it is possible to determine precisely which vessels are actively affected. In such cases, diagnosis and carrying out process monitoring during treat- ment is easy. Vessel wall imaging is a procedure already commonly used for other body areas, espe- cially black-blood sequences, i.e. T-1 weighted sequences that help to ‘darken’ blood. However, for the neuroradiological diagnosis of vas- culitis, a double suppression of both light blood signals and signals from adipose tissue is carried out because many of the basal cerebral vessels are located within adipose bone structures that impair the view of the inflamed vessel walls. Treatment makes the difference In addition to the neurological results, which mostly will already point towards a diagnosis, this technology can help to differenti- ate between vasculitis and embolic stroke without invasive examina- tions, which has a great effect on treatment. ‘Patients diagnosed with vasculitis are treated with immuno- suppressant drugs, such as cortisone, or others, depending on the extent of the disease and on which vessels are affected,’ the specialist explains. It has now emerged that the accu- mulation on the vessel walls is not actually 100% specific for vasculitis. ‘However, through process moni- toring we can determine whether improvements develop,’ Gizewski points out. ‘If the accumulation in the vessel walls decreases during treatment we know we are on the right track.’ The procedure can definitely be utilised as a follow-up marker.’ Vasculitis in the brain, an inflammation of the vessel walls resulting from autoimmune disorders, as yet has been difficult to diagnose with imaging procedures. Now, however, new and more sensitive MRI procedures and higher image resolution make it possible to visualise micro-infarction as well as the thickening of the vessel walls typical for vasculitis, even in the smaller cerebral vessels. This can be of great advantage specifically for younger patients, as Professor Elke Gizewski, neuroradiologist and Medical Director at the Department of Radiology at the Medical University of Innsbruck reports In the upper row the source images of the TOF-MR angiography show the constricted vessels (A. vertebralis right and A. carotis interna left), which are mainly affected. In the row below, the dark blood sequences correspond with significant contrast agent accumulation in the vessel walls Professor Elke Ruth Gizewski has directed the University Clinic for Neuroradiology at the Medical University of Innsbruck since 2012. Alongside her other commitments the professor is an assessor for multi- centre studies and specialises in functional and structural MRI, (Ultra-) High Field MRI and interven- tional neuroradiology attractive to trainees. The situation in France and Germany is particular- ly alarming. Both countries having had a very strong history of excel- lence within paediatric radiology; it is very sad to see desperation within the French and German speaking groups,’ she declares. Another particular problem is a substantial shortage of MR equip- ment, leading to long waiting lists. French patients have to wait 30.3 days to undergo an MR examina- tion, according to a report published last summer by the Imaging Health Future (Imagerie Santé Avenir, ISA) and France remains far behind its European counterparts with 11.9 MRI devices per million inhabitants, compared to an average of 20 across the rest of Europe, according to 2014 statistics. However, Owens insists that MR shortage and lack of trained exper- tise within optimising and reporting paediatric examinations is a global situation, as these examinations take longer and demand significant adap- tation of sequences and are chal- lenging in young patients. ‘Children often require sedation, or anaesthe- sia input, so MR exams take longer,’ Owens points out. ‘Not every imag- ing centre provides MR examina- tions under anaesthesia. MR access is a problem everywhere, with per- haps few exceptions, such as per- haps Switzerland and Luxemburg, which in terms of GDP spend more on healthcare.’ Furthermore, beyond neuroimag- ing, the quality of magnetic reso- nance scans is not always optimal in young patients because they are small; real knowledge is needed of the fundamental physical principles that must be optimised on site by an expert MR radiologist and physicist. Therefore, unless there is an expert in paediatric MR imaging to supervise protocol and to read the MR images, the quality of the examinations can be suboptimal, indeed poor. Nonetheless, MR is a really critical tool in paediatric imaging because it does not expose patients to ionis- ing radiation, unlike conventional X-rays or CT. Radiation effects are more hazardous in children, due to the immaturity of the tissues and longer expected life span. Moreover, repeated examinations over their lifetime causes cumulative radiation dose Radio-protection is therefore essential within paediatric radiology, and avoiding unnecessary irradiat- ing examinations remains the best protection. When these examina- tions need to be performed, and are deemed of benefit to the indi- vidual patient, radiologists should use appropriate child-friendly tech- niques and low dose technical set- tings. Unfortunately, the level of knowl- edge of child-focused imaging is heterogeneous amongst radiologists, many of whom are not sufficiently trained (being in adult centres) and not always adept at optimisation of their adult departmental equipment for children. Several guidelines on low-dose protocols exist, including from the ESPR, and ESR. But the diversity Continued from page 14 The International Day of Radiology Sensitive MRI procedures Europ_Hospital_103x133mm_R1-0.indd 114.10.201514:24:51

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