Safety of the Solitaire 4 × 40 mm Stent Retriever in the Treatment of Ischemic Stroke

CardioVascular and Interventional Radiology - Stent retrievers apply mechanical force to the intracranial vasculature. Our aim was to evaluate the safety and efficacy of the long Solitaire...     

Improved targeting of the α<Subscript>v</Subscript>β<Subscript>3</Subscript> integrin by multimerisation of RGD peptides

Purpose The integrin α_vβ₃ is expressed on sprouting endothelial cells and on various tumour cell types. Due to the restricted expression of α_vβ₃ in tumours, α_vβ₃ is considered a suitable receptor for tumour targeting. In this study the α_vβ₃ binding characteristics of an ¹¹¹In-labelled monomeric, dimeric and tetrameric RGD analogue were compared. Methods A monomeric (E-c(RGDfK)), dimeric (E-[c(RGDfK)]₂), and tetrameric (E{E[c(RGDfK)]₂}₂) RGD peptide were synthesised, conjugated with DOTA and radiolabelled with ¹¹¹In. In vitro α_vβ₃ binding characteristics were determined in a competitive binding assay. In vivo α_vβ₃ targeting characteristics of the compounds were assessed in mice with SK-RC-52 xenografts. Results The IC₅₀ values for DOTA-E-c(RGDfK), DOTA-E-[c(RGDfK)]₂, and DOTA-E{E[c(RGDfK)]₂}₂were 120 nM, 69.9 nM and 19.6 nM, respectively. At all time points, the tumour uptake of the dimer was significantly higher as compared to that of the monomer. At 8 h p.i., tumour uptake of the tetramer (7.40±1.12%ID/g) was significantly higher than that of the monomer (2.30±0.34%ID/g), p<0.001, and the dimer (5.17±1.22%ID/g), p<0.05. At 24 h p.i., the tumour uptake was significantly higher for the tetramer (6.82±1.41%ID/g) than for the dimer (4.22±0.96%ID/g), p<0.01, and the monomer (1.90±0.29%ID/g), p<0.001. Conclusion Multimerisation of c(RGDfK) resulted in enhanced affinity for α_vβ₃ as determined in vitro. Tumour uptake of a tetrameric RGD peptide was significantly higher than that of the monomeric and dimeric analogues, presumably owing to the enhanced statistical likelihood for rebinding to α_vβ₃.     

Usefulness of <Superscript>123</Superscript>I-metaiodobenzylguanidine myocardial scintigraphy for predicting the effectiveness of β-blockers in patients with dilated cardiomyopathy from the standpoint of long-term prognosis

Purpose The usefulness of ¹²³I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in predicting the effectiveness of -blocker therapy in dilated cardiomyopathy (DCM) was investigated from the standpoint of long-term prognosis.Methods The subjects were 53 DCM patients in whom -blockers had been successfully introduced and used for 6 months or longer. When symptoms were stable before the introduction of -blockers and for up to 1 year thereafter, MIBG myocardial single-photon emission computed tomography was performed and the images analysed to obtain the extent score (EXT), severity score (SEV) and washout rate (WR). At the same time, echocardiography was performed to measure left ventricular ejection fraction (LVEF). Thereafter, patients were placed under observation for an average of 1,314±986 days, with the occurrence of cardiac events as the endpoint.Results The degree of improvement in WR after introduction of -blockers was a significant predictor of cardiac events. In fact, none of the patients whose improvement in WR was valued at 10 or higher had cardiac events. Accordingly, using improvement in WR of 10 as the cut-off value, the patients were divided into two groups, improved and unimproved. There were significant differences between the groups in respect of early EXT, early SEV and WR before the introduction of -blockers . As regards predictors of WR improvement, multivariate logistic regression analysis demonstrated that early EXT, WR and LVEF were significant predictors.Conclusion This study shows that, from the standpoint of long-term prognosis, DCM patients who would benefit the most from -blocker therapy are those with low early EXT and early SEV and high WR before -blocker introduction regardless of LVEF values.     

Standardization of the heart-to-mediastinum ratio of <Superscript>123</Superscript>I-labelled-metaiodobenzylguanidine uptake using the dual energy window method: feasibility of correction with different camera–collimator combinations

Background  Although the heart-to-mediastinum (H/M) ratio in a planar image has been used for practical quantification in ¹²³I-metaiodobenzylguanidine (MIBG) imaging, standardization of the parameter is not yet established. We hypothesized that the value of the H/M ratio could be standardized to the various camera–collimator combinations. Methods and results  Standard phantoms consisting of the heart and mediastinum were made. A low-energy high-resolution (LEHR) collimator and a medium-energy (ME) collimator were used. We examined multi-window correction methods with ¹²³I- dual-window (IDW) acquisition, and planar images were obtained with IDW correction and the LEHR collimator. The images were obtained using the following gamma camera systems: GCA 9300A (Toshiba, Tokyo), E.CAM Signature (Toshiba/Siemens, Tokyo) and Varicam (GE, Tokyo). Cardiac phantom studies demonstrated that contamination of the H/M count ratio was greater with the LEHR collimator and least with the ME collimator. The corrected H/M ratio with the LEHR collimator was similar to that with ME collimators. The uncorrected H/M ratio with the ME collimator was linearly related to the H/M ratio with IDW correction with the LEHR collimator. The relationship between the uncorrected H/M ratios determined with the LEHR (E.CAM) and the ME collimators was y = 0.56x + 0.49, where y = H/M ratio with the E.CAM and x = H/M ratio with the ME collimator. The average normal values for the low-energy collimator (n=18) were 2.2±0.2 (initial H/M ratio) and 2.42±0.2 (delayed H/M ratio), and for the low/medium-energy (LME) collimator (n=14) were 2.63±0.25 (initial H/M ratio) and 2.87±0.19 (delayed H/M ratio). H/M ratios in previous clinical studies using LEHR collimators are comparable to those with ME collimators. Conclusion  The IDW-corrected H/M ratios determined with the LEHR collimator were similar to those determined with the ME collimator. This finding could make it possible to standardize the H/M ratio in planar imaging among various collimators in the clinical setting. An editorial commentary on this paper is available at     

Usefulness of brain <Superscript>99m</Superscript>Tc-TRODAT-1 SPET for the evaluation of Parkinson’s disease

Nigral dopaminergic projections to the striatum are targeted in Parkinsons disease (PD). The extent of the degeneration of the dopaminergic system in PD can be visualised by dopamine transporter imaging using single-photon emission tomography (SPET). In this study in 188 patients with PD, we analysed the image patterns and compared them with the clinical features in order to verify the usefulness of technetium-99m TRODAT-1 brain SPET in the evaluation of patients with PD. Two independent readers visually assessed SPET slices from three brain axes according to a fine visual scale; results were also grouped according to a rough visual scale. Results of both visual and semi-quantitative analyses were compared among patients with different stages of PD and healthy controls. There was good agreement between the readers in the interpretation of the image patterns [kappa statistic ()=0.85 for the presence of PD; =0.88 for the rough scale and 0.81 for the fine scale]. Good concordance was obtained when visual interpretation was used to evaluate the presence of PD (sensitivity =98%, specificity =86%, =0.85). Semi-quantitative analyses revealed significant negative correlations between both striatal and putaminal uptake and disease severity as assessed using the Hoehn and Yahr scale (=–0.89 and –0.93 respectively). An apparent decrease in striatal uptake in early PD, hardly discernible from the uptake level in advanced PD, was commonly found in visual analyses. The results suggest that both visual and semi-quantitative analyses of ^99mTc-TRODAT-1 SPET images reflect neurodegeneration in PD, and that ^99mTc-TRODAT-1 SPET represents an adequate means for evaluation of the status of patients with PD.     

Liver parenchymal enhancement of hepatocyte‐phase images in Gd‐EOB‐DTPA‐enhanced MR imaging: Which biological markers of the liver function affect the enhancement?

Purpose:

To clarify the factors that predict enhancement of the liver parenchyma in hepatocyte‐phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced MR imaging.

Materials and Methods:

Gd‐EOB‐DTPA–enhanced hepatocyte‐phase MR images of 198 patients with chronic liver diseases (Child‐Pugh class A in 112 patients, class B in 74 patients, and class C in 12 patients) were retrospectively analyzed. The hepatocyte‐phase images were obtained using fat‐suppressed T1‐weighted gradient‐echo images with a 3D acquisition sequence 10 min and 20 min after IV administration of Gd‐EOB‐DTPA (0.025 mmol/kg body weight). The quantitative liver–spleen contrast ratio (Q‐LSC) was calculated using the signal intensities of the liver and spleen. Serum albumin levels, total bilirubin levels, prothrombin activity, and the results of indocyanine green clearance tests (ICGs) were recorded and correlated with the Q‐LSC. Logistic regression analysis was performed to analyze which factors predict sufficient liver enhancement using a Q‐LSC of 1.5 as a cutoff value.

Results:

Only ICGs and Child‐Pugh classifications showed a statistically significant correlation with the Q‐LSC. Logistic regression analysis showed that ICGs were the only factors that accurately predicted liver enhancement on hepatocyte‐phase images.

Conclusion:

ICGs were found to be predictors of sufficient liver enhancement on hepatocyte‐phase images. J. Magn. Reson. Imaging 2009;30:1042–1046. © 2009 Wiley‐Liss, Inc.     

Does a skiing intervention influence the psycho‐social characteristics of the elderly?

The purpose of this study was to assess whether a guided alpine skiing intervention lasting 12 weeks has an impact on psycho-social dimensions, measured by subjective assessments, of individuals who are 60+ years of age. A number of well-established questionnaires were used to measure well-being, life satisfaction, self-concept, health status, depression and self-efficacy. The physical self-concept in the domain "strength" increased significantly in the intervention group from pre- to post-test and remained stable through the retention test, whereas the control group demonstrated nearly no alteration. A similar effect was obtained in life satisfaction for the dimension "friends and relatives." On the contrary, psycho-social aspects of the elderly were not negatively influenced. The subjects of this study had very high pre-test scores that might reflect a ceiling effect which, in turn, can explain the marginal positive impact of the intervention. The findings of this study argue for recommending a guided alpine skiing intervention for individuals who are 60 years of age and older with high values in psycho-social variables.     

Sonographic diagnosis of pneumoperitoneum using the ‘<Emphasis Type="Italic">enhancement of the peritoneal stripe sign</Emphasis>.’ A prospective study

The objective of this study was to validate the Enhanced Peritoneal Stripe Sign (EPSS) in diagnosing pneumoperitoneum in patients presenting with acute abdomen. The EPSS was described as a specific sonographic sign of pneumoperitoneum in an animal model and few patients who had undergone laparoscopy (Muradali et al. in Am J Roentgenol 173(5): 1257–1262, 1999). This is the first large-scale study in patients to detect the efficacy of EPSS. Six hundred consecutive patients with acute abdominal pain presenting to the author over a period of 3 months in the emergency ultrasonography department were prospectively studied for the presence of the EPSS. As part of their clinical work up, patients also underwent plain radiographs and/or a computed tomography (CT) of the abdomen. The author was unaware of the results of other imaging studies at the time of the sonographic examination. In all cases, the final diagnosis was based on the intra-operative findings, results of other imaging techniques and clinical follow-up. Based on the final diagnosis, 21 out of 600 patients had pneumoperitoneum. The EPSS was found to be positive in all 21 of these patients. Another three patients were found to have the sign false positive. There were no false negatives in this study. The EPSS thus had a sensitivity of 100%, a specificity of 99%, a positive predictive value of 87.5% and a negative predictive value of 100%. The EPSS is a reliable and accurate sonographic sign for the diagnosis of pneumoperitoneum. It should be looked for in all patients presenting with acute abdominal pain.     

Model for the correction of motion‐induced phase errors in multishot diffusion‐weighted‐MRI of the head: Are cardiac‐motion‐induced phase errors reproducible from beat‐to‐beat?

In diffusion-weighted imaging, multishot acquisitions are problematic due to intershot inconsistencies of the phase caused by motion during the diffusion-encoding gradients. A model for the motion-induced phase errors in diffusion-weighted-MRI of the brain is presented, in which rigid-body and nonrigid-body motion are separated. In the model, it is assumed that nonrigid-body motion is due to cardiac pulsation, and that the motion patterns are repeatable from beat-to-beat. To test the validity of this assumption, the repeatability of nonrigid-body motion-induced phase errors is quantified in three healthy volunteers. Nonrigid-body motion-induced phase was found to significantly correlate (P < 0.05) with pulse-oximeter waveforms in ~83% of the pixels tested across all slices and subjects.     

Comparison of <Superscript>99m</Superscript>Tc-annexin A5 with <Superscript>18</Superscript>F-FDG for the detection of atherosclerosis in ApoE−/− mice

Purpose ^99mTc-annexin A5, a marker of ongoing apoptosis, and ¹⁸F-FDG, a marker of the increased metabolism of inflammatory cells, are supposed to be useful in the detection of metabolically active atheroma. This study reports a comparison of the intralesional distribution of these tracers in relation to lesion development in ApoE−/− mice. Methods Male ApoE−/− mice (n = 12–14/group) were maintained on a Western-type diet after the age of 5 weeks. At 25 weeks, ^99mTc-annexin A5 or ¹⁸F-FDG was injected and the aortas were harvested for autoradiography (ARG) and Oil Red O staining. Regional radioactivity accumulation was compared in relation to the Oil Red O staining score (ranging from 0 to 3, a semiquantitative parameter for evaluating lesion development). Results Both ^99mTc-annexin A5 and ¹⁸F-FDG showed preferential uptake into atherosclerotic lesions, with higher uptake levels for ¹⁸F-FDG (mean, 56.07 %ID×kg/m²) than for ^99mTc-annexin A5 (mean, 10.38 %ID×kg/m²). The regional uptake levels of each tracer correlated with the Oil Red O staining score (r = 0.65, p < 0.05 for ^99mTc-annexin A5; r = 0.56, p < 0.05 for ¹⁸F-FDG). The uptake ratios of advanced lesions (score >0.5) to early lesions (score <0.5) were significantly higher for ^99mTc-annexin A5 than for ¹⁸F-FDG (f = 4.73, p = 0.03). Conclusion Both ^99mTc-annexin A5 and ¹⁸F-FDG accumulate in atherosclerotic lesions and correlate with the severity of each lesion. The higher absolute uptake levels of ¹⁸F-FDG may be advantageous for lesion detection, whereas the preferential uptake of ^99mTc-annexin A5 in advanced lesions may be a useful indicator of late-stage lesions or vulnerable plaque transformation.     

Is there a BOLD response of the visual cortex on stimulation of the vision‐related acupoint GB 37?

PURPOSE: To determine whether or not acupuncture of guangming (GB 37) produces a significant response of the visual cortex detectable by means of functional magnetic resonance imaging (fMRI). MATERIALS AND METHODS: This study investigates the activation of the visual cortex elicited by a soft and an intensified stimulation of GB 37, an acupoint documented to influence vision-related disorders. Three different paradigms were carried out to detect any possible modulation of the Blood Oxygenation Level Dependent (BOLD)-response in the visual cortex to visual stimulation through acupuncture. RESULTS: The percentage signal changes in the visual stimulation cycles did not significantly differ before vs. during acupuncture. CONCLUSION: Whereas no BOLD-response correlating with acupuncture was detected in the visual cortex, BOLD-signal-changes in response to needle twisting were detected in different cortical areas. Further studies are necessary to clarify whether these clusters correlate to inevitable somatosensory stimulation accompanying acupuncture or represent an acupuncture-specific response.     

The angioarchitectural factors of the cerebral developmental venous anomaly; can they be the causes of concurrent sporadic cavernous malformation?

Introduction  

The aim of this paper was to evaluate the angioarchitectural factors that can induce concurrent cavernous malformation (CM) in the territory of developmental venous anomaly (DVA).