Contrast-enhanced ultrasound with microbubbles containing sulfur hexafluoride and perfluorobutane with Kupffer phase for the detection of colorectal liver metastases.

OBJECTIVE: To compare contrast-enhanced ultrasound (CEUS) with microbubbles containing sulfur hexafluoride (SHF) and perfluorobutane (PFB) for the detection of colorectal liver metastasis (CRLM). METHODS: In this prospective study, conducted from September to November 2021, patients with colorectal cancer were consecutively recruited and underwent same-day ultrasound, SHF-CEUS, and PFB-CEUS. The reference standard was contrast-enhanced MRI and follow-up imaging. The size, depth, echogenicity, and calcification of each focal liver lesion were recorded. The number and conspicuity of CRLMs, based on washout appearance during the late phase (LP) (> 120 s)/Kupffer phase (KP), were evaluated offsite by two blinded readers. RESULTS: Overall, 230 lesions (CRLMs, n = 219; benign lesions, n = 11) in 78 patients were evaluated. Lesion conspicuity (p = 0.344) and accuracy in the detection of CRLM were comparable for SHF- and PFB-CEUS (0.877 for SHF vs. 0.770 for PFB, p = 0.087). More CRLMs ≥ 10 mm were identified by LP contrast washout in SHF-CEUS than in KP PFB-CEUS (p < 0.001). More CRLMs < 10 mm were identified by KP washout in PFB-CEUS than in LP SHF-CEUS (p < 0.001). Conspicuity was better on PFB-CEUS than on SHF-CEUS (p = 0.027). In hyperechoic lesions, lesions located deeper than 80 mm, and calcified lesions, CRLM conspicuity on PFB-CEUS was inferior to that on SHF-CEUS (p < 0.05). CONCLUSIONS: The overall accuracy of detection and conspicuity of washout in CRLMs were comparable between SHF and PFB-CEUS. PFB-CEUS has the advantage of identifying washout in small CRLMs. However, larger, hyperechogenic, deep-seated, or calcified lesions were better identified using SHF-CEUS. CLINICAL RELEVANCE STATEMENT: Accuracy of detection and conspicuity of washout in CRLMs were comparable between SHF- and PFB-CEUS. PFB-CEUS has the advantage in detecting small CRLMs, whereas SHF-CEUS is better for detecting larger, hyperechogenic, deep-seated, or calcified lesions. KEY POINTS: Contrast-enhanced ultrasound with sulfur hexafluoride in the late phase and perfluorobutane microbubbles in the Kupffer phase were comparable in terms of accuracy in the detection and conspicuity of colorectal liver metastases. Small colorectal liver metastases (< 10 mm) were more often identified in the Kupffer phase contrast-enhanced ultrasound imaging when using perfluorobutane microbubbles. Larger, hyperechogenic, deep-seated, or calcified lesions were better identified in the late phase contrast-enhanced ultrasound imaging (> 120 s) when using sulfur hexafluoride microbubbles.

SF 6 COMPARED WITH C 2 F 6 FOR INFERIOR RHEGMATOGENOUS RETINAL REPAIR : The Manchester Pseudophakic Retinal Detachment Study.

PURPOSE: To compare SF 6 relative with C 2 F 6 in the anatomical and functional outcomes following pars plana vitrectomy for uncomplicated primary pseudophakic rhegmatogenous retinal detachment with inferior causative breaks. METHODS: This is a retrospective, comparative study on eyes with pseudophakic rhegmatogenous retinal detachment with inferior causative breaks that had small-gauge pars plana vitrectomy repair using SF 6 and C 2 F 6 tamponade between 2011 and 2020 at a tertiary centre in the United Kingdom. Primary outcome was single surgery anatomical success, and the secondary outcome was best-corrected visual acuity. Propensity score matching, using preoperative findings as covariates to account for relevant confounders, was performed. RESULTS: From 162 pseudophakic rhegmatogenous retinal detachment eyes with inferior causative breaks, the median (interquartile range) follow-up was 82 (52-182) days. The single surgery anatomical success was 156 (96.3%) overall: 47 of 47 (100.0%) and 109 of 115 (94.8%) in the SF 6 and C 2 F 6 groups, respectively ( P = 0.182). Relative to the SF 6 group, the C 2 F 6 group had a higher mean number of tears (SF 6 : 3.1[2.0], C 2 F 6 : 4.5[2.7], P = 0.002) and greater retinal detachment extent (SF 6 : 5.3[2.9], C 2 F 6 : 6.2[2.6] clock hours, P = 0.025). Following propensity score matching analysis, 80 eyes were matched with 40 in each group to homogenize preoperative factors. No significant difference was found in single surgery anatomical success and best-corrected visual acuity between the groups following propensity score matching. CONCLUSION: Primary pars plana vitrectomy with gas tamponade leads to a high single surgery anatomical success rate in uncomplicated pseudophakic rhegmatogenous retinal detachment with inferior causative breaks with no additional benefit associated with long-acting tamponade when comparing C 2 F 6 with SF 6 .

Displacement of Submacular Hemorrhage Using Subretinal Cocktail Injection versus Pneumatic Displacement: A Real-World Comparative Study.

INTRODUCTION: The objective of this study was to compare the outcome of submacular hemorrhage (SMH) displacement using pneumatic displacement with intravitreal expansile gas versus pars plana vitrectomy (PPV) with subretinal injection of tissue plasminogen activator (tPA), anti-vascular endothelial growth factor (VEGF) agent, and air as primary surgery. METHODS: Retrospective interventional case series of 63 patients who underwent surgical displacement of SMH secondary to neovascular age-related macular degeneration (nAMD) or polypoidal choroidal vasculopathy (PCV) from May 1, 2015, to October 31, 2022. Medical records were reviewed for diagnosis, logMAR visual acuity (VA), central subfield thickness (CST), and postoperative displacement rates and complications up to 12 months after operation. RESULTS: The diagnosis was nAMD in 24 (38.1%) and PCV in 39 (61.9%) eyes. There were 40 (63.5%) eyes in the pneumatic displacement group (38 received C3F8, 2 received SF6) and 23 (36.5%) eyes in the subretinal cocktail injection. Mean baseline VA was 1.46 and 1.62, respectively (p = 0.404). The subretinal injection group had more extensive SMH (p = 0.005), thicker CST (1,006.6 µm vs. 780.2 µm, p = 0.012), and longer interval between symptom and operation (10.65 vs. 5.53 days, p < 0.001). The mean postoperative VA at 6 months was 0.67 and 0.91 (p = 0.180) for pneumatic displacement and subretinal injection groups, respectively, though VA was significantly better in the pneumatic group at 12-month visit (0.64 vs. 1.03, p = 0.040). At least 10 mean change in VA were >10 letters gain in both groups up to 12 months. Postoperative CST reduction was greater (625.1 µm vs. 326.5 µm, p = 0.008) and complete foveal displacement (87.0% vs. 37.5%), p < 0.001, odds ratio [OR] = 11.1) and displacement to arcade or beyond (52.5% vs. 17.5%, p = 0.009, OR = 5.15) were more frequent in the subretinal injection group. Two patients with failed pneumatic displacement were successfully treated with subretinal cocktail injection as a second operation. CONCLUSION: Surgical displacement of SMH leads to clinically meaningful improvement in VA. PPV with subretinal cocktail injection is more effective than pneumatic displacement in displacing SMH with similar safety profile despite longer interval before operation, higher CST, and more extensive SMH at baseline. Retinal surgeons could consider this novel technique in cases with thick and extensive SMH or as a rescue secondary operation in selected cases.

Pulmonary Transit Time Assessment by CEUS in Healthy Rabbits: Feasibility, and the Effects of UCAs Dilution Concentration.

To evaluate the inter-observer variability and the intra-observer repeatability of pulmonary transit time (PTT) measurement using contrast-enhanced ultrasound (CEUS) in healthy rabbits, and assess the effects of dilution concentration of ultrasound contrast agents (UCAs) on PTT. Thirteen healthy rabbits were selected, and five concentrations UCAs of 1:200, 1:100, 1:50, 1:10, and 1:1 were injected into the right ear vein. Five digital loops were obtained from the apical 4-chamber view. Four sonographers obtained PTT by plotting the TIC of right atrium (RA) and left atrium (LA) at two time points (T1 and T2). The frame counts of the first appearance of UCAs in RA and LA had excellent inter-observer agreement, with intra-class correlations (ICC) of 0.996, 0.988, respectively. The agreement of PTT among four observers was all good at five different concentrations, with an ICC of 0.758-0.873. The reproducibility of PTT obtained by four observers at T1 and T2 was performed well, with ICC of 0.888-0.961. The median inter-observer variability across 13 rabbits was 6.5% and the median variability within 14 days for 4 observers was 1.9%, 1.7%, 2.2%, 1.9%, respectively; The PTT of 13 healthy rabbits is 1.01 ± 0.18 second. The difference of PTT between five concentrations is statistically significant. The PTT obtained by a concentration of 1:200 and 1:100 were higher than that of 1:1, while there were no significantly differences in PTT of a concentration of 1:1, 1:10, and 1:50. PTT measured by CEUS in rabbits is feasible, with excellent inter-observer and intra-observer reliability and reproducibility, and dilution concentration of UCAs influences PTT results.

Contrast-enhanced ultrasound of polyp malignant transformation with multiple metastases in a patient with Peutz-Jeghers syndrome.

Multi-systemic metastasis in patients with Peutz-Jeghers syndrome (PJS) is very rare, and there are nearly no relevant imaging reports, especially in contrast-enhanced ultrasound (CEUS). We present here a 40-year-old male patient who underwent several partial small bowel resections and endoscopic polypectomy for intestinal polyps. After reviewing the patient's clinical diagnosis and treatment process, CEUS with sulfur hexafluoride microbubbles (SonoVue, Bracco, Milan, Italy) in the liver and gastrointestinal tract was performed. We imaged multiple abnormal masses with sonographic features consistent with malignancies. Combined with other imaging examinations and 18 gauge core-needle puncture biopsy of liver masses, multiple metastases outside the gastrointestinal tract were considered. This case report suggests CEUS may be an easy, effective, and supplementary method for evaluating PJS patients with suspected multi-systemic malignant lesions including the gastrointestinal tract.

Gas-Sensing Performance of Metal Oxide Heterojunction Materials for SF6 Decomposition Gases: A DFT Study.

The online monitoring of GIS equipment can be realized through detecting SF6 decomposition gasses. Metal oxide heterojunctions are widely used as gas-sensing materials. In this study, the structural and electrical properties of In2O3-ZnO and TiO2-ZnO heterojunctions were analyzed based on density functional theory calculations. After heterojunction structural optimization, the electrical conductivity of these two heterojunctions was enhanced compared to each intrinsic model, and the electrical conductivity is ranked as follows: In2O3-ZnO heterojunction > TiO2-ZnO heterojunction. The gas-sensing response of these two heterojunctions to four SF6 decomposition gasses, H2S, SO2, SOF2, and SO2F2, was investigated. For gas adsorption systems, the adsorption energy, charge transfer, density of states, charge difference density, and frontier molecular orbitals were calculated to analyze the adsorption and gas-sensing performance. For gas adsorption on the In2O3-ZnO heterojunction surface, the induced conductivity changes are in the following order: H2S > SO2F2 > SOF2 > SO2. For gas adsorption on the TiO2-ZnO heterojunction surface, H2S and SOF2 increase conductivity, and SO2 and SO2F2 decrease conductivity.

Contrast-enhanced US with Sulfur Hexafluoride and Perfluorobutane: LI-RADS for Diagnosing Hepatocellular Carcinoma.

Background Liver Imaging Reporting and Data System (LI-RADS) was designed for contrast-enhanced US (CEUS) with pure blood pool agents to diagnose hepatocellularfcarcinoma (HCC), such as sulfur hexafluoride (SHF), but Kupffer-cell agents, such as perfluorobutane (PFB), allow additional lesion characterization in the Kupffer phase yet remain unaddressed. Purpose To compare the diagnostic performance of three algorithms for HCC diagnosis: two algorithms based on CEUS LI-RADS version 2017 for both SHF and PFB and a modified algorithm incorporating Kupffer-phase findings for PFB. Materials and Methods This multicenter prospective study enrolled high-risk patients for HCC from June 2021 to December 2021. Each participant underwent same-day SHF-enhanced US followed by PFB-enhanced US. Each liver observation was assigned three LI-RADS categories according to each algorithm: LI-RADS SHF, LI-RADS PFB, and modified PFB. For modified PFB, observations at least 10 mm with nonrim arterial phase hyperenhancement were upgraded LR-4 to LR-5 if there was no washout with a Kupffer defect and were reassigned LR-M to LR-5 if there was early washout with mild Kupffer defect. The reference standard was pathologic confirmation or composite (typical CT or MRI features, or 1-year size stability and/or reduction). Diagnostic metrics of LR-5 for HCC using the three algorithms were calculated and compared using the McNemar test. Results Overall, 375 patients (mean age, 56 years ± 11 [SD]; 318 male patients, 57 female patients) with 424 observations (345 HCCs, 40 non-HCC malignancies, 39 benign lesions) were enrolled. PFB and SHF both using LI-RADS showed no significant difference in sensitivity (60% vs 58%; P = .41) and specificity (96% vs 95%; P > .99). The modified algorithm with PFB had increased sensitivity (80% vs 58%; P < .001) and a nonsignificant decrease in specificity (92% vs 95%; P = .73) compared with LI-RADS SHF. Conclusion Based on CEUS LI-RADS version 2017, both SHF and PFB achieved high specificity and relatively low sensitivity for HCC diagnosis. When incorporating Kupffer-phase findings, PFB had higher sensitivity without loss of specificity. Chinese Clinical Trial Registry no. ChiCTR2100047035 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Kim in this issue.

Safety findings after intravenous administration of sulfur hexafluoride microbubbles to 463,434 examinations at 24 centers.

OBJECTIVES: We aimed to evaluate the safety of the ultrasound contrast agent sulfur hexafluoride microbubbles in a large group of patients referred for routine contrast-enhanced ultrasound (CEUS). METHODS: A retrospective assessment was made of all patients that received sulfur hexafluoride microbubbles intravenously for CEUS at 24 centers between January 2006 and April 2019. Patient demographic details, examination type, and the dose of sulfur hexafluoride microbubbles administered were recorded with specific adverse events (AEs) documentation tools at each center. All AEs were recorded as serious or non-serious. Non-serious AEs were classified by intensity as mild, moderate, or severe according to ACR criteria. The frequencies of AEs across patient subgroups were compared using the chi-square test. RESULTS: A total of 463,434 examinations were evaluated. Overall, 157 AEs (153 [0.033%] non-serious; 4 [0.001%] serious) were reported after sulfur hexafluoride microbubbles administration, giving an AE frequency of 0.034% (157/463,434). Among the non-serious AEs, 66 (0.014%) were mild, 70 (0.015%) moderate, and 17 (0.004%) severe in intensity. The liver was the most common examination site, presenting an AE frequency of 0.026%. The highest AE frequency (0.092%) was for patients undergoing CEUS for vascular disease. There were no significant gender differences in either the total number or the severity of non-serious AEs (chi-square = 2.497, p = 0.287). The onset of AEs occurred within 30 min of sulfur hexafluoride microbubbles administration in 91% of cases. CONCLUSION: The frequency of AEs to sulfur hexafluoride microbubbles is very low and severe reactions are rare, confirming that sulfur hexafluoride microbubbles are appropriate for routine CEUS applications. KEY POINT: • The frequency of AEs to sulfur hexafluoride microbubbles is very low and severe reactions are rare.

Vitrectomy with sulfur hexafluoride versus air tamponade for idiopathic macular hole: a retrospective study.

BACKGROUND: To evaluate the effect of room air and sulfur hexafluoride (SF6) gas in idiopathic macular hole(MH)surgery. METHODS: Retrospective, interventional, and comparative study. 238 eyes with the idiopathic macular hole that underwent pars plana vitrectomy, internal limiting membrane peeling, fluid-air exchange, and 20% SF6 (SF6 group:125 eyes) or room air tamponade (air group: 113 eyes) were reviewed. The primary outcome measure was the closure rate of primary surgery. RESULTS: The baseline characteristics of the SF6 group and air group were comparable except for the hole size (479.90 ± 204.48 vs. 429.38 ± 174.63 µm, P = 0.043). The anatomical closure rate was 92.8% (116 / 125) with the SF6 group and 76.1% (86 / 113) with the air group (P < 0.001). A cut-off value of MH size to predict primary anatomical closure was 520 µm, which is based on the lower limit of 95% confidential interval of the MH size among the unclosed patients in the air group. There was no significant difference in anatomical closure rates between SF6 and air group (98.7% vs. 91.9%, P = 0.051) for MH ≤ 520 µm, whereas a significantly lower anatomical closure rate was shown in the air group than SF6 group (46.2% vs. 84.0%, P < 0.001) for MH > 520 µm. CONCLUSION: SF6 exhibited more effectiveness than air to achieve a good anatomical outcome for its longer tamponade when MH > 520 µm.

A rare case of echo enhancing agent anaphylaxis complicated by acute coronary syndrome.

Enhancing agents in echocardiography are used frequently to improve endocardial border visualization and assessment of structural heart disease. We present a unique case of anaphylactic shock with acute coronary syndrome following administration of sulfur hexafluoride echo enhancing agent. This case emphasizes the importance of recognizing anaphylaxis to enhancing agents, as well as recognizing the potential relationship between anaphylaxis and acute coronary syndrome with in-stent thrombosis.

Is Hysterosalpingo-Contrast Sonography (HyCoSy) Using Sulfur Hexafluoride Microbubbles (SonoVue) Sufficient for the Assessment of Fallopian Tube Patency? A Systematic Review and Meta-Analysis.

This study aimed to evaluate the diagnostic value of HyCoSy using sulfur hexafluoride microbubbles for fallopian tubal patency assessment in infertile females. Twenty-four studies, including 1358 females with 2661 detected fallopian tubes published from January 2003 to May 2019, were identified. The pooled sensitivity was 93% (95% CI: 90-95%), while the specificity was 90% (95% CI: 87-92%). The area under the receiver-operating characteristic curve was 0.96 (95% CI: 94-98%). The specificity of the four-dimensional HyCoSy subgroup was higher than the 2D/3D subgroup; an increased dose of contrast agent did not affect the specificity, with only a slightly reduced sensitivity.

Risk Factors of Contrast Agent Intravasation With Sulfur Hexafluoride Microbubble During Hysterosalpingo-Contrast Sonography.

OBJECTIVES: To analyze the risk factors of sulfur hexafluoride microbubble contrast agent intravasation during hysterosalpingo-contrast sonography (HyCoSy), and to explore a simple prediction model by the obvious clinical history. METHODS: This was a retrospective study included 299 infertility women who had undergone HyCoSy examination from July 1, 2018 to June 31, 2019. The factors were recorded, including age, endometrial thickness, balloon length, infertility type, history of intrauterine surgery, history of pelvic surgery, and tubal patency. The method of multivariate logistic regression analysis was adopted to analyze the risk factors affecting the contrast agent intravasation, and the receiver operating characteristic curves were plotted to test their efficacy. RESULTS: Secondary infertility, a history of intrauterine surgery, thin endometrial thickness, and tubal obstruction were all risk factors of the occurrence of intravasation (P < .05). And the area under the receiver operating characteristic curves of the multifactor-combined prediction model of the intravasation was significantly larger than that of single-factor. CONCLUSIONS: Sonographers and gynecologists should be familiar with the risk factors of intravasation and select the appropriate timing of HyCoSy toward reducing the occurrence of intravasation and other complications after thoroughly explaining and communicating with the patients.

Effect of temperature on the acoustic response and stability of size-isolated protein-shelled ultrasound contrast agents and SonoVue.

Limited work has been reported on the acoustic and physical characterization of protein-shelled UCAs. This study characterized bovine serum albumin (BSA)-shelled microbubbles filled with perfluorobutane gas, along with SonoVue, a clinically approved contrast agent. Broadband attenuation spectroscopy was performed at room (23 ± 0.5 °C) and physiological (37 ± 0.5 °C) temperatures over the period of 20 min for these agents. Three size distributions of BSA-shelled microbubbles, with mean sizes of 1.86 µm (BSA1), 3.54 µm (BSA2), and 4.24 µm (BSA3) used. Viscous and elastic coefficients for the microbubble shell were assessed by fitting de Jong model to the measured attenuation spectra. Stable cavitation thresholds (SCT) and inertial cavitation thresholds (ICT) were assessed at room and physiological temperatures. At 37 °C, a shift in resonance frequency was observed, and the attenuation coefficient was increased relative to the measurement at room temperature. At physiological temperature, SCT and ICT were lower than the room temperature measurement. The ICT was observed to be higher than SCT at both temperatures. These results enhance our understanding of temperature-dependent properties of protein-shelled UCAs. These findings study may guide the rational design of protein-shelled microbubbles and help choose suitable acoustic parameters for applications in imaging and therapy.

New Alternative Techniques for Sentinel Lymph Node Biopsy.

Background and Objectives: This review paper highlights the key alternatives to the blue dye/radioisotope method of sentinel lymph node biopsy (SLNB). It analyses the research available on these alternative methods and their outcomes compared to the traditional techniques. Materials and Methods: This review focused on fifteen articles, of which five used indocyanine green (ICG) as a tracer, four used magnetic tracers, one used one-step nucleic acid amplification (OSNA) and Metasin (quantitative reverse transcriptase-polymerase chain reaction), one used the photosensitiser talaporfin sodium, one used sulphur hexafluoride gas microbubbles, one used CT-guided lymphography and two focused on general SLNB technique reviews. Results: Of the 15 papers analysed, the sentinel node detection rates were 69-100% for indocyanine green, 91.67-100% for magnetic tracers, 81% for talaporfin sodium, 9.3-55.2% for sulphur hexafluoride gas microbubbles, 90.5% for CTLG and 82.7-100% for one-step nucleic acid amplification. Conclusions: Indocyanine green fluorescence (ICG) and magnetic tracers have been proven non-inferior to traditional blue dye and isotope regarding SLNB localisation. Further studies are needed to investigate the use of these techniques in conjunction with each other and the possible use of language learning models. Dedicated studies are required to assess cost efficacy and longer-term outcomes.

Transient tracer gas measurements: Development and evaluation of a fast-response SF6 measuring system based on quartz-enhanced photoacoustic spectroscopy.

This study aims to develop a fast-response sulfur hexafluoride (SF6 ) measuring system, and evaluate its performance in tracer gas measurements for studying transient airborne contaminant transport. The new system is based on a quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor using a quantum cascade laser. Transient SF6 tracer gas measurements were carried out in an environmental chamber with an instantaneous source using both the QEPAS system and a traditional commercial instrument. Real-time SF6 concentrations, peak SF6 concentrations and average SF6 concentrations for one room time constant under two air change rates obtained by the two instruments were compared. The results show that the QEPAS system, which features a 0.4 s data acquisition interval, can provide detailed real-time SF6 concentrations even when the concentration is changing rapidly. The QEPAS system successfully captured the peak SF6 concentrations for all the studies cases, while commercial instrument failed in most studied cases. In most of the cases, the two instruments obtained similar average SF6 concentrations for one room time constant. However, when the concentration was in rapid change, the two systems would report significantly different results. The QEPAS system can be potentially applied in transient tracer gas measurements under complex scenarios.

AIR VERSUS SULFUR HEXAFLUORIDE GAS TAMPONADE IN VITRECTOMY FOR UNCOMPLICATED RETINAL DETACHMENT WITH INFERIOR BREAKS.

PURPOSE: To compare surgical outcomes of filtered air and sulfur hexafluoride (SF6) as an internal tamponade in patients undergoing primary 25-gauge pars plana vitrectomy for uncomplicated rhegmatogenous retinal detachment with inferior breaks. METHODS: Patients with uncomplicated rhegmatogenous retinal detachment associated with inferior breaks (between 4 and 8 o'clock positions) who were undergoing primary pars plana vitrectomy were enrolled. All eyes underwent pars plana vitrectomy and complete drainage of subretinal fluid, followed by filtered air or 20% SF6 tamponade. The main outcome measures included single-surgery anatomical success rates and final visual recovery. RESULTS: Overall, 116 eyes of 116 patients (81 men and 35 women with a mean age of 55.2 years) were assessed. Air was used in 52 eyes (air group) and gas in 64 eyes (gas group). Single-surgery anatomical success was achieved in 50 (96.2%) and 60 (93.8%) eyes in the air and gas groups, respectively (P = 0.69), and final anatomical success was achieved in all eyes. The mean final Snellen visual acuity was similar in the air (20/23) and gas groups (20/21; P = 0.13). CONCLUSION: No significant differences were observed in single-surgery anatomical success rates and final visual recovery when comparing air with SF6 gas tamponade in pars plana vitrectomy for primary uncomplicated rhegmatogenous retinal detachment with inferior breaks.

LONG-TERM VISUAL OUTCOMES AND THE TIMING OF SURGICAL REPAIR OF FOVEA-SPLITTING RHEGMATOGENOUS RETINAL DETACHMENTS.

PURPOSE: To evaluate the visual outcomes and the affect of timing of surgical repair of fovea-splitting rhegmatogenous retinal detachments. METHOD: A retrospective, consecutive cohort from multiple surgeons at a single center. Fovea status (fovea-on, fovea-splitting, or fovea-off) was classified by preoperative optical coherence tomography. The primary outcome measure was the visual acuity at the last follow-up that was further correlated with the timing of surgical repair. RESULTS: One hundred and ninety-five eyes were included with 62 fovea-on, 65 fovea-splitting, and 68 fovea-off detachments. The mean preoperative logarithm of the minimum angle of resolution visual acuity for fovea-on, fovea-splitting, and fovea-off groups was 0.16 ± 0.21, 0.70 ± 0.56, and 1.67 ± 0.87, respectively (P = <0.001). Mean postoperative logarithm of the minimum angle of resolution visual acuity for fovea-on, fovea-splitting, and fovea-off groups were 0.07 ± 0.13, 0.10 ± 0.15, and 0.20 ± 0.22, respectively (P = <0.001). A statistically significant difference in mean postoperative logMAR visual acuity was found between fovea-off and fovea-on groups (P = 0.003) and between fovea-off and fovea-splitting groups (P = 0.013), however not between fovea-on and fovea-splitting groups (P = 0.827). Visual acuity improved when repair was performed earlier after presentation for fovea-on (R = 0.378, P = 0.002) and fovea-off groups (R = 0.277, P = 0.022), but not for the fovea-splitting group (R = 0.089, P = 0.481). CONCLUSION: We described the favorable visual outcomes of surgery for fovea-splitting rhegmatogenous retinal detachment and correlated these with the timing of surgical repair, which may help guide the management of this urgent, vision-threatening condition.

RESTORATION PROCESS OF THE OUTER RETINAL LAYERS AFTER SURGICAL MACULAR HOLE CLOSURE.

PURPOSE: To investigate the interrelationship among the outer retinal layers after macular hole surgery and elucidate the restoration process. METHODS: This retrospective observational study included 50 eyes of 47 consecutive patients with closed macular holes in the first vitrectomy. Optical coherence tomography was obtained before surgery; at 1, 3, and 6 months postsurgery; and at the last visit. The complete continuous layer rate and mean defect length were evaluated for the outer nuclear layer (ONL), external limiting membrane (ELM), and ellipsoid zone (EZ). RESULTS: At all postoperative visits, the complete continuous layer rate was in the descending order of ELM, ONL, and EZ and the mean defect length was in the ascending order of ELM, ONL, and EZ. External limiting membrane was necessary for ONL restoration. External limiting membrane and ONL were necessary for EZ restoration. Hyperreflective protrusions were observed from the area lacking ELM into the subretinal space after surgery. Ellipsoid zone was not formed in coexistence with the hyperreflective protrusions. Intermediate reflective protrusions appeared under the ONL plus ELM after surgery and were eventually replaced by EZ. CONCLUSION: Restoration of the outer retinal layers after surgical macular hole closure occurs in the order of ELM, ONL, and EZ.

Extreme learning machine and genetic algorithm in quantitative analysis of sulfur hexafluoride by infrared spectroscopy.

Owing to the general disadvantages of traditional neural networks in gas concentration inversion, such as slow training speed, sensitive learning rate selection, unstable solutions, weak generalization ability, and an ability to easily fall into local minimum points, the extreme learning machine (ELM) was applied to sulfur hexafluoride (SF6) concentration inversion research. To solve the problems of high dimensionality, collinearity, and noise of the spectral data input to the ELM network, a genetic algorithm was used to obtain fewer but critical spectral data. This was used as an input variable to achieve a genetic algorithm joint extreme learning machine (GA-ELM) whose performance was compared with the genetic algorithm joint backpropagation (GA-BP) neural network algorithm to verify its effectiveness. The experiment used 60 groups of SF6 gas samples with different concentrations, made via a self-developed Fourier transform infrared spectroscopy instrument. The SF6 gas samples were placed in an open optical path to obtain infrared interference signals, and then spectral restoration was performed. Fifty groups were randomly selected as training samples, and 10 groups were used as test samples. The BP neural network and ELM algorithms were used to invert the SF6 gas concentration of the mixed absorbance spectrum, and the results of the two algorithms were compared. The sample mean square error decreased from 248.6917 to 63.0359; the coefficient of determination increased from 0.9941 to 0.9984; and the single running time decreased from 0.0773 to 0.0042 s. Comparing the optimized GA-ELM algorithm with traditional algorithms such as ELM and partial least squares, the GA-ELM algorithm had higher prediction accuracy and operating efficiency and better stability and generalization performance in the quantitative analysis of small samples of gas under complex noise backgrounds.

Targeted Delivery of Salusin-α Into Rabbit Carotid Arterial Endothelium Using SonoVue.

OBJECTIVES: A new method based on the adhesion of SonoVue to plasmids was assessed to achieve targeted gene delivery into the vascular endothelium. METHODS: pEGFP-Salusin-α and pcDNA3.1-Salusin-α plasmids were transfected into the arterial endothelium of different rabbit groups. Western blotting was performed to analyze the expression of EGFP and salusin-α in the common carotid arteries of rabbits from different groups, and ELISA was performed to detect plasma salusin-α levels in rabbits from each group; simultaneously, blood parameters of different groups of rabbits were measured. RESULTS: Green fluorescence was observed in the right common carotid artery of rabbits transfected with pEGFP-Salusin-α, but not in the endothelial cells of not-transfected control rabbits. The expression of salusin-α in the transfected animals was higher than that in the control not-transfected animals (P < .05). In rabbits transfected with pcDNA3.1-Salusin-α plasmid, salusin-α expression was higher than in the not-transfected control animals (P < .05). However, there was no significant difference in plasma salusin-α levels between transfected animals and controls (P > .05). Blood parameters were also measured in both groups. CONCLUSIONS: Our data confirm the establishment of a new method using SonoVue for targeted gene delivery into the arterial endothelium. Our study outcomes propose a new method of intervention in atherosclerosis and a new tool for targeted gene delivery.