[en] Magnetic resonance imaging (MRT) is increasingly utilized as the primary imaging modality in major stroke centers. The ability to depict several aspects of individual pathophysiology makes the use of MRI in stroke both attractive and complex. Profound knowledge of the pathophysiology of the imaging findings is crucial for a rational diagnostic workup. The pathophysiology of MRI in stroke will be reviewed considering recent experiences in clinical application, and the potential of stroke MRI will be assessed. Further perspectives like application of 'blood oxygen level dependent' (BOLD) and the use of multiparametric prediction maps will be discussed. (orig.)

[en] Purpose: To compare image quality in magnetic resonance cholangiopancreatography (MRCP) performed with and without oral application of Loesferron ^trademark (ferrous gluconate, Lilly Pharma, Hamburg). Materials and Methods: A prospective study compares MRCPs performed on 52 patients with a 1.5 T clinical whole body scanner using a standard body coil. After randomization, patients ingested either 0.5 l of Loeseferron ^trademark (n=27, group 1) or no oral contrast agent (n=25, group 2) prior to the examination. 7 RARE (40 to 20 ) sequences were obtained, followed by selected 3 mm HASTE (T₂-weighted with fat suppression) sequences. After blinding, image quality was rated by two radiologists using a scale of 1 (not discernible) to 5 (very well discernible). The following sections of the biliary ductal system were evaluated: left and right hepatic duct, extrahepatic bile duct and intrapancreatic bile duct. The pancreatic duct was evaluated by its location: head, body and tail of the pancreas. A Wilcoxon-Mann-Whitney test was used to determine significant differences (p<0.05) between sampled ductal segments. Correction for multiple testing was applied. Results: The oral application of Loeseferron ^trademark was well tolerated by all patients, and all sequences could be acquired and evaluated in all 52 patients. For the different sections of the biliary system, the mean ratings with and without Loesferron ^trademark were, respectively, 3.28 and 3.36 for the left hepatic duct, 3.26 and 3.33 for the right hepatic duct, 3.46 and 4.0 for the extrahepatic bile duct, and 2.8 and 3.48 for the intrapancreatic bile duct. The corresponding ratings for the pancreatic duct were 2.8 and 3.24 for the pancreatic head, 2.84 and 3.38 for the pancreatic body, and 2.68 and 3.22 for the pancreatic tail. The differences with and without contrast agent were not statistically significant. Interobserver variability was between 0.37 for the pancreatic duct in the tail of the pancreas and 0.66 for the right hepatic duct. Conclusion: Despite the trend toward a better rating of the image quality for all sections of the pancreaticobiliary ductal system with Loesferron^circledR, a significant difference was not found in any ductal section after correction for multiple testing. Thus, we believe that the ingestion of Loeseferron ^trademark is not absolutely required prior MRCP. (orig.)

[en] Arterial spin labeling blood perfusion signal relies on the difference between a label and a control image. Background suppression pulses are commonly used to improve the contrast, yet these are based on estimates of tissue relaxation times. The aim of this study is to improve the perfusion contrast by individualizing the timing of these background suppression pulses by means of T1 mapping. The optimized timing of the background suppression pulses is obtained by rapid T1 mapping employing the variable flip angle technique. Ten healthy volunteers were included in this study. To compare the results, visual grading and the Wilcoxon signed-rank test was used comparing three categories of image quality. The readers confirmed that the images of the proposed method generally show a higher signal-to-background ratio and cortical structures are better visible. Noise was mostly comparable to the standard method. Relative blood flow was statistically significant higher in the modified method. The individually optimized background suppression pulses improve the image appearance and allow for a better visualization of cortical structures. The proposed technique however prolongs scan time, which can be seen as negative result, yet needs to be further evaluated. Background suppression timing in ASL can vary. Both the label and control condition can be modified for T1 mapping. Adapting the pulse timing improves the signal-to-background ratio.

[en] Acute vertebrobasilar occlusions (VBO) are dramatic clinical events with a mortality of up to 90% under standard medical treatment. If VBO is suspected a diagnosis of the vessel status has to be achieved immediately. For this purpose CT/CTA and MRI/MRA are equivalent diagnostic tools in the emergency setting. In contrast to the anterior circulation, local endovascular treatment is the established therapy for the posterior circulation as an underlying arteriosclerotic stenosis remains in 50% of the cases after intravenous fibrinolysis. Nevertheless, systemic fibrinolysis is considered the preferred option in cases where a neurointerventional center cannot be reached within a reasonable time frame and the patient can subsequently be transported for local therapy of a residual stenosis in order to prevent reocclusion (''drip and ship''). Profound clinical and pathophysiological knowledge is the absolute prerequisite for the correct application of state-of-the-art neurointerventional therapy. This review paper focuses on the clinical and pathophysiological details that are crucial for decision-making. (orig.)

[en] Purpose: evaluation of hospital resource allocation in intracranial aneurysm treatment in a medium-volume neurovascular center. Materials and methods: retrospective data analysis included 653 procedures performed on 598 patients with 667 aneurysms (A) from 1990 to 2004. 515 treatments were carried out in ruptured A (clip: n = 370; coil: n = 145) and 138 procedures in non-ruptured A (clip: n = 51, coil: n = 87). Patient management data included procedure time (min), length of stay in the intensive care unit (days), total length of hospital stay (days), and discharge to home ratio. Results: clinical admission grade (rupt. A: Hunt and Hess grade 1-3: clip: 73% coil: 72%) and clinical outcome at discharge (good neurological outcome/mortality rate: rupt. A: clip: 51.1/13.8% coil: 45.5/10.3% non-rupt. A: 88.2/0% coil: 88.5/1.3%) were similar for both treatment modes. The coil procedure time was found to be significantly shorter (rupt. A: coil: 145 min; clip: 203 min; p < 0.01; non-rupt. A: coil: 164 min, clip: 200 min; p < 0.01). Coiling reduced the length of stay in the ICU (rupt. A: coil: 5.3 d; clip: 6d, p < 0.01; non-rupt. A: coil: 1.5d; clip: 2d; p = 0.21) and coiling significantly reduced the length of hospital stay (rupt. A: coil: 21.4d; clip: 26.8 d, p < 0.01; non-rupt. A: coil: 9.2d; clip: 17.5d; p = 0.01). The discharge to home ratio did not differ (rupt. A: clip: 31.6% coil: 29.7% nonrupt. A: clip: 74.5% coil: 80.5%). Conclusion: in a medium-volume neurovascular center, coiling significantly reduced the procedure time, the stay in the ICU, and the length of hospital stay suggesting favorable resource allocation in endovascular therapy. (orig.)

[en] An efficient therapy of MS requires a quick and reliable diagnosis of the disease. MRI is the most leading paraclinical examination for MS diagnosis. Even though there is no pathognomic finding in MRI, there are MS characteristics with respect to morphology and localization. To exclude other neurological disorders and distinguish between different characteristics within MS, the use of contrast agent is advantageous. Postulated MRI criteria have been increasingly adjusted to the clinical routine and have become clearer, more sensitive, and more specific. Different imaging criteria will be introduced. In addition to the McDonald criteria of 2001 and 2005, new criteria will be presented in which the use of contrast agent is replaced by a second MRI and the dissemination in time and space is simplified. Different pathomechanisms which help to separate MS patients into subgroups are postulated. The diverse pathomechanisms also enable the development of new pharmaceuticals to manipulate the immunologic course in different stages. For varying therapy approaches, it is increasingly important to differentiate the heterogeneous appearance forms into subtypes. The two visible main components of the disorder in MRI are inflammation and neurodegeneration and are responsible for different clinical courses. Both are interdependent and independent of each other. We introduce a stratification which uses both components as a function of their different outcomes to compose subgroups. The previous challenge with respect to MRI was to support the diagnosis of MS via MRI criteria. A future problem will be the heterogeneity and classification of subgroups. This article gives an overview of both problems. (orig.)

[en] To evaluate the incidence of additional thoracic pathologic findings (TPF) detected on scout views and corresponding bolus tracking slices (SVBT) for computed tomographic cerebral angiography (CTCA) and to test the reliability and accuracy of these findings. The study collective included 505 consecutive patients who underwent multidetector CTCA. Appendant SVBT of all patients were reviewed for any pathologic findings and patient medical reports were analyzed, if any medical treatment was initiated for the detected pathologic findings. In 18 patients thoracic CT scans were performed in the same session. These were additionally reviewed by two blinded observers to test for intra- and interobserver reliability as well as for accuracy of detecting thoracic pathologies on SVBT. TPF were detected in 165 (33 %) SVBT. The five most common pathologic findings were: pleural effusion, 12 %; pneumonia, 8 %; atelectasis/dystelecatsis, 6 %; pericardial effusion, 2 % and elevated diaphragm, 1 %. For 48 % of these findings medical treatment was initiated. SVBT showed a sensitivity of 53 %, a specificity of 99 %, a positive predictive value of 89 %, a negative predictive value of 94 % and accuracy of 94 % for the detection of TPF. The intraobserver reliability was very good and the interobserver reliability showed moderate agreement. SVBT for CTCA should be reviewed with care by radiologists, since additional TPF can affect patient management. Nevertheless, despite a high specificity of SVBT for detecting TPF, an only moderate sensitivity has to be taken into account.

[en] Carotid angioplasty and stenting (CAS) has widely replaced balloon angioplasty (percutaneous transluminal angioplasty, PTA) in the treatment of internal carotid artery stenosis (ICAS). Here we assess whether the use of stents increases the safety and long-term efficacy of angioplasty in patients with ICAS. Our aim was to test the hypothesis that the long-term efficacy of CAS is superior to that of PTA. At the University Medical Center Hamburg-Eppendorf, PTA was performed from 1990 to 1997 and CAS was performed from 1998 to 2006. All patients undergoing these procedures were symptomatic. Selection and follow-up examinations were performed by independent vascular neurologists. Follow-up terms were 1, 3, 6 and 12 months, then annually. In the PTA group (n = 71), 2.8% of the patients showed severe periinterventional complications (i.e. lasting neurological deficits). Of these 71 patients, 57.7% were followed up for an average period of 51 months. Stenois >70% was observed in 9.8% of the PTA patients, while 4.9% of the patients had ipsilateral occlusions. In the CAS group (n = 354), 4.2% of the patients showed severe periinterventional complications. In total, 61% of the CAS patients were followed up for an average period of 25 months, of whom 4.6% showed stenosis of >70% and 1.9% had ipsilateral occlusions. Periprocedural complications and new symptoms that appeared during follow-up occurred at a rate of 5.6% (PTA) and 5.9% (CAS). There was no difference in the rate of annual ipsilateral events (1.1% in PTA vs. 1.3% in CAS, p = 1.000) Overall, the use of stents, rather than PTA only, shows no beneficial clinical effect in the treatment of ICA stenosis. While the rate of restenosis may be significantly reduced, this merely suggests that the impact of restenosis is less apparent than expected. (orig.)

[en] To compare intra- and inter-observer reliability of aneurysm measurements obtained by a 3D computer-aided technique with standard manual aneurysm measurements in different imaging modalities. A total of 21 patients with 29 cerebral aneurysms were studied. All patients underwent digital subtraction angiography (DSA), contrast-enhanced (CE-MRA) and time-of-flight magnetic resonance angiography (TOF-MRA). Aneurysm neck and depth diameters were manually measured by two observers in each modality. Additionally, semi-automatic computer-aided diameter measurements were performed using 3D vessel surface models derived from CE- (CE-com) and TOF-MRA (TOF-com) datasets. Bland-Altman analysis (BA) and intra-class correlation coefficient (ICC) were used to evaluate intra- and inter-observer agreement. BA revealed the narrowest relative limits of intra- and inter-observer agreement for aneurysm neck and depth diameters obtained by TOF-com (ranging between ±5.3 % and ±28.3 %) and CE-com (ranging between ±23.3 % and ±38.1 %). Direct measurements in DSA, TOF-MRA and CE-MRA showed considerably wider limits of agreement. The highest ICCs were observed for TOF-com and CE-com (ICC values, 0.92 or higher for intra- as well as inter-observer reliability). Computer-aided aneurysm measurement in 3D offers improved intra- and inter-observer reliability and a reproducible parameter extraction, which may be used in clinical routine and as objective surrogate end-points in clinical trials. (orig.)

[en] Purpose: We present long-term clinical and duplex data from high-risk patients with severe, recurrent symptomatic stenoses of the vertebrobasilar circulation. We hypothesized that despite the greater risk of periprocedural complications in this patient group, interventional treatment would reduce the risk of recurrent strokes relative to the expected natural risk. We also predicted that the long-term treatment outcome would be positively influenced by the use of stents and by the periprocedural technical success rate. Materials and Methods: An analysis of our patient data base yielded 45 cases of stenosis of the vertebrobasilar circulation treated endovascularly in 42 patients between 1998 and 2006. Clinical and vascular diagnostic tests, both periinterventionally and during follow-up, were performed independently by experienced neurologists. Results: The technical success rate was 93%. Stents were used in 67% of the procedures. After 30 days, 24% of the patients showed post-procedural clinical deterioration. After an average period of 26.3 months, 17.8% of the patients had deteriorated. 11.1% of the patients suffered severe permanent damage as a result of the procedure (mRs 3-6). Restenosis was found in 9.5% of the cases. There were no instances of a recurrent stroke during follow-up. Conclusion: For this population of high-risk patients with recurrently symptomatic intracranial stenoses of the vertebrobasilar axis, endovascular treatment reduced the risk of stroke and death relative to the expected natural risk. The use of stents had no significant effect on the long-term results. (orig.)