Image post-processing corrects for cardiac and respiratory motion (MoCo) during cardiovascular magnetic resonance (CMR) stress perfusion. The study analyzed its influence on visual image evaluation.
Materials and methods
Sixty-two patients with (suspected) coronary artery disease underwent a standard CMR stress perfusion exam during free-breathing. Image post-processing was performed without (non-MoCo) and with MoCo (image intensity normalization; motion extraction with iterative non-rigid registration; motion warping with the combined displacement field). Images were evaluated regarding the perfusion pattern (perfusion deficit, dark rim artifact, uncertain signal loss, and normal perfusion), the general image quality (non-diagnostic, imperfect, good, and excellent), and the reader’s subjective confidence to assess the images (not confident, confident, very confident).
Results
Fifty-three (non-MoCo) and 52 (MoCo) myocardial segments were rated as ‘perfusion deficit’, 113 vs. 109 as ‘dark rim artifacts’, 9 vs. 7 as ‘uncertain signal loss’, and 817 vs. 824 as ‘normal’. Agreement between non-MoCo and MoCo was high with no diagnostic difference per-patient. The image quality of MoCo was rated more often as ‘good’ or ‘excellent’ (92 vs. 63%), and the diagnostic confidence more often as “very confident” (71 vs. 45%) compared to non-MoCo.
Conclusions
The comparison of perfusion images acquired during free-breathing and post-processed with and without motion correction demonstrated that both methods led to a consistent evaluation of the perfusion pattern, while the image quality and the reader’s subjective confidence to assess the images were rated more favorably for MoCo.
In this work, a nanohybrid material based on a freestanding polymeric liquid crystal network capable of postmodification via cation exchange to tune birefringence is proposed. The smectic liquid crystal films can be infiltrated with a variety of cations, thereby changing the refractive indices (ne and no) and the effective birefringence (Δn) of the nanohybrid material, with reversible cation infiltration occurring within minutes. Birefringence could be tuned between values of 0.06 and 0.19, depending on the cation infiltrated into the network. Upon infiltration, a decrease in the smectic layer spacing is found with layer contraction independent of the induced change in birefringence. Potential applications are in the field of specialty optical devices, such as flexible, retunable reflective filters. 相似文献
Periodic and quasi-periodic structures, printed on a dielectric substrate, can be employed to control the reflection and transmission properties of incident waves as a function of structure geometry. Local variations of the element geometry on a substrate with backside metallization - resulting in respective variations of the reflection phase angle - can be used to design printed reflectarray antennas. The dual-polarization properties of such antennas, together with polarizing grids or slot arrays, can be exploited for the realization of compact, low-profile folded reflector antennas. Examples of some antennas of this type are presented, covering the 60 GHz range for communication and ISM applications, and 76 to 77 GHz for automotive radars. 相似文献
Fingolimod, an oral sphingosine 1-phosphate (S1P) receptor modulator, is approved for the treatment of relapsing forms of multiple sclerosis (MS). The interference with S1P signaling leads to retention particularly of chemokine receptor-7 (CCR7) expressing T cells in lymph nodes. The immunological basis of varicella zoster virus (VZV) infections during fingolimod treatment is unclear. Here, we studied the dynamics of systemic and intrathecal immune responses associated with symptomatic VZV reactivation including cessation of fingolimod and initiation of antiviral therapy. Key features in peripheral blood were an about two-fold increase of VZV-specific IgG at diagnosis of VZV reactivation as compared to the previous months, a relative enrichment of effector CD4+ T cells (36% versus mean 12% in controls), and an accelerated reconstitution of absolute lymphocytes counts including a normalized CD4+/CD8+ ratio and reappearance of CCR7+ T cells. In cerebrospinal fluid (CSF) the lymphocytic pleocytosis and CD4+/CD8+ ratios at diagnosis of reactivation and after nine days of fingolimod discontinuation remained unchanged. During this time CCR7+ T cells were not observed in CSF. Further research into fingolimod-associated VZV reactivation and immune reconstitution is mandatory to prevent morbidity and mortality associated with this potentially life-threatening condition. 相似文献
Necrotizing fasciitis is a rapidly progressing, synergistic bacterial infection of fascia with a reported average mortality of about 40%. Fournier's disease, necrotizing fasciitis of the genital sphere, is also included in this study. Seven patients were studied over a one-year period between May 1991 and October 1992. Most commonly, they were infected by perineal diseases, medical procedures and cutaneous ulcers. The local clinical signs are cellulitis, oedema, blisters, necrosis and crepitus; general septic symptoms may also be present. Associated chronic diseases were present in 4 patients. Three infections were polymicrobial. Control of this potentially lethal soft-tissue infection is based on early clinical diagnosis, timely, wide surgical debridements and appropriate antibiotic treatment. The overall mortality rate was 1 of 7 (14%). Death was due to persistent wound sepsis and systemic septic complications, but mainly to delay in surgical treatment. The presence of chronic debilitating diseases (diabetes, alcohol abuse, renal insufficiency, ...) contribute to increase rate of both local and systemic infection. 相似文献
Vitamin A palmitate can be directly determined by HPLC in the margarine fat phase. Omitting saponification leads to a considerable saving in analysis time, and to reduced losses during sample clean-up. The result is obtained ca. 12 min after the HPLC injection, and one analysis incl. sample preparation can be carried out in ca. 30-45 min - when the HPLC equipment is running and calibrated. A similar method can be developed for vitamin A acetate in margarines. Initial results using azobenzene as an internal standard are also reported. 相似文献
Divided rats according to their responses to startle-eliciting stimuli into 2 groups with different emotional states. About half of the 54 female Sprague-Dawley rats showed long-lasting freezing behavior after 1–8 stimuli (10 kHz, 110 dB spl). In freezing rats the startle amplitude was higher than in nonfreezing rats, even on the very first startle response. This finding demonstrates that the anxiety state of these animals before the 1st startle-eliciting stimulus, and not just the aversiveness of the stimulus, contributes to freezing behavior. In addition, in freezing rats there was no influence of spontaneous motor activity or of adaptation time on startle amplitude. Only in nonfreezing rats were high motor activities correlated with lowered startle amplitudes, and only in these rats did the course of startle habituation depend on adaptation time. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献