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vention and i.v. thrombolysis. The research is ongoing. Most neurologists and neuroradiologists agree that functional brain imaging could be the key to making this distinction, for example the measurement of the brain perfusion. At the moment, this is usually done by CT or MRI. With the Artis Q system, Prof. Skalej and his collaborating partners from Siemens have embarked on a research project that aims to make functional diagnostics available for angiography systems. The option to measure the parenchymal blood volume (syngo DynaPBV Neuro) as a static perfusion parameter has already become part of the product. Prof. Skalej is convinced that more perfusion-related parameters will follow: “syngo DynaPBV Neuro is the first step. Now we are working on how to determine dynamic parameters like the cerebral blood flow (CBF) and mean transit time (MTT). If we succeed, hospitals will truly be able to offer one-stop stroke management in the angio suite and to set CT aside.” syngo DynaCT Micro and i.v. syngo DynaCT DSA Extend the Spectrum One-stop stroke management is definitely on the horizon, but the technology is not quite there yet. Other features of the Artis Q system are, even today, extending the possibilities of routine neuroradiological care. One feature that Prof. Skalej particularly likes is the option of performing an intravenously injected syngo DynaCT-angiogram with the Artis Q: “I.v. syngo DynaCT angiography works extremely well with the Artis Q. It is not possible to achieve the same image quality with other systems since there are far more artifacts and resolution is much poorer.” Prof. Skalej is using i.v. syngo DynaCT for follow-up examinations of patients with stents or flow-diverters. After implantation of these devices, follow-up examinations are necessary every three to six months. They can be done as arterial angiographies, but this is a more invasive procedure than the i.v. angiography, which only requires a small hollow needle in the vein to administer contrast medium. “The patient group that most benefits from intra-arterial interventions has not yet been well defined. But we know, for example, that a thrombus of more than eight millimeters in length in the middle cerebral artery almost never disappears with i.v. thrombolysis alone. These are the patients who typically benefit from interventional therapies.” In Magdeburg, around 60 out of 800 stroke patients a year are being treated with interventional therapies. “This is a good number for a city like Magdeburg with its rural surroundings. In fact, with our 60 intra-arterial stroke interventions per year, we are already getting close to the aneurysm interventions, of which we perform 80 per year.” Within this broader trend towards a more diversified treatment paradigm for stroke patients, the Artis Q system offers an exciting prospect: thanks to the increase in image quality, “one-stop stroke management” may become possible. Patients with suspected stroke who are referred to the hospital by emergency services could have all the necessary diagnostics and initial treatment in the angio suite, very similar to patients with myocardial infarction who nowadays are brought directly into the cath lab without any further delay. Functional Diagnostics for Angio Systems One-stop stroke management is dependent on two things: first, it is necessary to exclude intracranial bleeding directly with the angiography system and not, as currently standard, with a diagnostic CT or MRI. The introduction of the Artis Q system was a massive step forward in this respect. Once a hemorrhage is excluded, patients can be treated with either i.v. thrombolysis or intra-arterial recanalization without having to transport them to a different room or relocate them. The second important step is to differentiate between patients who benefit most from i.v. thrombolysis and patients who benefit from an intra-arterial intervention or a combination of interlooking Angiography Artis Q at the correct projection and that we have coiled the aneurysm completely. I am convinced that this translates into fewer complications and thus increased patient safety.” Another example that shows the clinical relevance of better image quality is cancer patients with bone metastases in the spinal cord. These patients are treated with radio-frequency ablation (RFA), a technology that heats the tissue to 80 to 100 degrees centigrade in order to selectively destroy the tumor. “The difficulty is placing the needles so that the tumor tissue and not the medulla is targeted. This is much easier when the image quality is good. So we now perform almost all spinal cord interventions in tumor patients on the new angiography system.” The improvements in X-ray tube and detector technology can also be used to reduce radiation dose while maintaining image quality, says Prof. Skalej: “In fluoroscopic interventions, we will always go for maximum image quality to ensure that the implants are optimally placed. But in follow-up examinations, or in situations where we only need an overview image, the option for dose reduction is really intriguing.” Acute Stroke – Time is Brain Even more intriguing are the new opportunities that the Artis Q system creates in the management of patients with acute stroke. For many years, the standard of care in patients with acute ischemic stroke was intra venous thrombolysis – provided that the patient arrived early enough at the hospital for the thrombolytic agent to be administered within 4.5 hours after onset of stroke. In recent years, however, new interventional treatments of patients with ischemic stroke have increasingly gained acceptance. With the aid of stent technology and intra-arterial retriever devices, thrombolytic material is extracted from the vessel and blood flow restored. Prof. Skalej emphasizes that, for the moment, intravenous (i.v.) thrombolysis remains standard of care: 20  AXIOM Innovations | December 2013 | www.siemens.com/angiography


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