Purpose:To characterize human gliomas using T 1 -weighted dynamic contrast-enhanced MRI (DCE-MRI), and directly compare three pharmacokinetic analysis techniques: a conventional established technique and two novel techniques that aim to reduce erroneous overestimation of the volume transfer constant between plasma and the extravascular extracellular space (EES) (K trans ) in areas of high blood volume. Materials and Methods:Eighteen patients with high-grade gliomas underwent DCE-MRI. Three kinetic models were applied to estimate K trans and fractional blood plasma volume (v p ). We applied the Tofts and Kermode (TK) model without arterial input function (AIF) estimation, the TK model modified to include v p and AIF estimation (mTK), and a "first pass" variant of the TK model (FP). Results:K TK values were considerably higher than K mTK and K FP values (P Ͻ 0.001). K mTK and K FP were more comparable and closely correlated ( ϭ 0.744), with K mTK generally higher than K FP (P Ͻ 0.001). Estimates of v p(mTK) and v p(FP) also showed a significant difference (P Ͻ 0.001); however, these values were very closely correlated ( ϭ 0.901). K TK parameter maps showed "pseudopermeability" effects displaying numerous vessels. These were not visualized on K mTK and K FP maps but appeared on the corresponding v p maps, indicating a failure of the TK model in commonly occurring vascular regions. Conclusion:Both of the methods that incorporate a measured AIF and an estimate of v p provide similar pathophysiological information and avoid erroneous overestimation of K trans in areas of significant vessel density, and thus allow a more accurate estimation of endothelial permeability.

Background Empirical evidence suggests that there is a significant genetic influence in the development of posttraumatic stress disorder (PTSD). The serotonin transporter (5-HTT) gene (SLC6A4) has been identified as a prime candidate for the development of the disorder, as 5-HTT is a working target for selective serotonin reuptake inhibitors (SSRIs), first line treatment agents for PTSD. Several studies have reported associations between 5-HTT-linked promoter region (5-HTTLPR) polymorphism variants and increased rates of PTSD in civilian samples. This study investigated the role of the 5-HTTLPR polymorphism, triallelically classified, in a sample of combat veterans with and without PTSD. Methods Rates of PTSD were examined across three genotypes in a sample of 388 combat veterans. The short/long polymorphism of 5-HTTLPR and the A-G polymorphism within the 5-HTTLPR (rs25531) were genotyped, and statistical analyses were conducted. Results There were significant intergroup (PTSD versus non-PTSD) differences in the genotype frequencies of 5-HTTLPR/rs25531 (χ2[1, n=388]=16.23, P=5.62×10−5). The 5-HTTLPR S′/S′ (low transcriptionally efficient) genotype was also associated with the PTSD severity score in the 228 participants who had combat severity data (r=.15, P=0.03). Conclusions The findings are consistent with previous research among civilian populations that have indicated that the low transcriptionally efficient S′/S′ genotype of 5-HTTLPR is a risk factor for the development of PTSD after trauma exposure. Our findings are the first to examine this polymorphism and PTSD in a military sample. Additional large-scale investigations are needed to replicate these findings.

Background: Second harmonic imaging is a new ultrasound technique that allows evaluation of brain tissue perfusion after application of an ultrasound contrast agent. Objective: To evaluate the potential of this technique for the assessment of abnormal echo contrast characteristics of different brain tumours. Methods: 27 patients with brain tumours were studied. These were divided into four groups: gliomas, WHO grade III-IV (n = 6); meningiomas (n = 9); metastases (n = 5); and others (n = 7). Patients were examined by second harmonic imaging in a transverse axial insonation plane using the transtemporal approach. Following intravenous administration of 4 g (400 mg/ml) of a galactose based echo contrast agent, 62 time triggered images (one image per 2.5 seconds) were recorded and analysed offline. Time-intensity curves of two regions of interest (tumour tissue and healthy brain tissue), including peak intensity (PI) (dB), time to peak intensity (TP) (s), and positive gradient (PG) (dB/s), as well as ratios of the peak intensities of the two regions of interest, were derived from the data and compared intraindividually and interindividually. Results: After administration of the contrast agent a marked enhancement of echo contrast was visible in the tumour tissue in all patients. Mean PI and PG were significantly higher in tumour tissue than in healthy brain parenchyma (11.8 v 5.1 dB and 0.69 v 0.16 dB/s; p < 0.001). TP did not differ significantly (37.1 v 50.2 s; p = 0.14). A tendency towards higher PI and PG as well as shorter TP was apparent in malignant gliomas. When comparing different tumour types, however, none of these variables reached significance, nor were there significant differences between malignant and benign tumours in general. Conclusions: Second harmonic imaging not only allows identification of brain tumours, but may also help in distinguishing between different tumour types. It gives additional and alternative information about tumour perfusion. Further studies are needed to evaluate the clinical potential of this technique in investigating brain tumours-for example in follow up investigations of patients undergoing radiation or chemotherapy-especially in comparison with neuroradiological and neuropathological findings.

Recurrent TIA or stroke after VAD appears to be extremely rare, independent of recanalization or persistent occlusion of the affected artery. CDUS and TCCDUS provide reliable follow-up of VAD in all patients presenting with stenosis or occlusion, but do not allow for detection of pseudoaneurysms of the VA.

Paradoxical embolism is an acknowledged cause of stroke in young patients with patent foramen ovale (PFO).1-4 Previous publications have addressed the suspected mechanisms of stroke, concomitant factors increasing the risk of embolic events and the available treatment options. [5][6][7][8][9][10][11][12][13] In regard to stroke mechanism, most studies focus on paradoxical embolism and underlying deep venous thrombosis, which can be difficult to demonstrate. [14][15][16] Nevertheless, other factors facilitating thrombus formation, such ABSTRACT: Background: It is unclear whether medical or invasive (surgical or catheter interventional) treatment is preferable to prevent recurrence of cerebral ischemia in patients with patent foramen ovale (PFO) as the suspected cause of stroke and what the role of concomitant risk factors is in stroke recurrence. Methods: Over a period of ten years, 124 patients (mean age 51 ± 15 years) with cryptogenic cerebral ischemia and PFO were included into the study and prospectively followed over a mean of 52 ± 32 months. Of these, 83 were treated medically, 34 underwent transcatheter closure, and seven had surgical closure of the foramen. Of the medically treated patients, 11 stopped medication during follow-up. Recurrent ischemic events and risk factors for recurrence were analyzed. Results: Annual stroke recurrence rates were generally low and comparable in catheter and medically treated patients, and in patients who had stopped medication (2.9%/2.1%/2.2%/year). Patients suffering from recurrence after transcatheter closure (n=2) both had residual shunts. No stroke recurrence was observed in the few surgically treated patients. An atrial septal aneurysm was not a predictor of recurrent or multiple strokes (p>0.05, OR=0.31, and OR=0.74). Large shunts and a history of previous ischemic events were considerably more frequent in patients with recurrent strokes (p<0.05, OR=5.0, and OR=4.4). Pulmonary embolism and case fatality rates were significantly higher in patients with stroke recurrence (p<0.001, and p<0.01). Conclusions: The absolute risk of recurrent cerebrovascular events in patients with PFO receiving medical or catheter interventional therapy is low. The small group of untreated patients had a comparably low rate of stroke recurrences. Previous ischemic events and shunt size were risk factors in this observational study. Given conflicting findings across multiple studies, enrollment into a randomized controlled trial would be the optimal choice. RÉSUMÉ: La récidive de l'accident vasculaire cérébral et sa prévention chez les patients porteurs d'un foramen ovale perméable. Contexte:On ignore si le traitement médical ou le traitement effractif est préférable pour prévenir la récidive de l'ischémie cérébrale chez les patients porteurs d'un foramen ovale perméable (FOP) qu'on soupçonne être la cause d'un accident vasculaire cérébral (AVC) et quel rôle jouent les facteurs de risque concomitants dans la récidive de l'AVC. Méthodes: Cent vingt-quatre patients porteurs d'un FOP et ayant ...