Contrast Staining Research Articles

Complex Method of CT and Morphological Examination of Placental Angioarchitechtonics.

We propose an original method of complex assessment of the placental angioarchitechtonics based on computed tomography (CT) and morphological examination. A prerequisite condition of successful examination and assessment of the placental angioarchitechtonics is the pre-preparative stage including clearing of the placental and umbilical cord vessels from blood clots by placement of placenta into 10% hypertonic NaCl solution and then on a hygroscopic substrate. The major stage of this method is injection of contrast staining mixtures into the umbilical vessels followed by CT. The concentration of radiocontrast agent in water solution of gouache should be 70% for arteries and 15% for veins. The volumes of mixtures for contrast staining should be calculated according to the weight of the placenta. The contrast staining mixture was first injected into the catheterized unpaired umbilical vein, and then into both umbilical arteries. Each injection of the contrast staining mixture was visually inspected; then branching of the stained vessel was photographed and scanned by CT. The CT scans were used to construct 3D models of placental vessels and spectral color maps, which made it possible to examine the peculiarities of placental angioarchitechtonics, to identify and evaluate anastomoses of placental vessels, and to establish the type of these anastomoses.

Self-Repair in Cacti Branches: Comparative Analyses of Their Morphology, Anatomy, and Biomechanics.

Damage-repair is particularly important for the maintenance of the water-storing abilities of succulent plants such as cacti. Comparative morphological, anatomical, and biomechanical analyses of self-repair were performed on artificially wounded branches of Opuntia ficus-indica and Cylindropuntia bigelovii. Macroscopic observations, contrast staining, and lignin-proof staining were used to investigate morphological and anatomical responses after wounding at various time intervals. Two-point bending tests were repeatedly performed on the same branches under unwounded, freshly wounded, and healed conditions by using customized 3D-printed clamping jaws. Morphologically, both species showed a rolling-in of the wound edges, but no mucilage discharge. Anatomically, ligno-suberized peridermal layers developed that covered the wound region, and new parenchyma cells formed, especially in O. ficus-indica. In all samples, the wounding effect directly after damage caused a decrease between 18% and 37% in all the tested mechanical parameters, whereas a positive healing effect after 21 days was only found for C. bigelovii. Based on our data, we hypothesize a high selection pressure on the restoration of structural integrity in the wound area, with a focus on the development of efficient water-retaining mechanisms, whereas the concept of “sufficient is good enough” seems to apply for the restoration of the mechanical properties.

Comparative Analysis of P63, Maspin and Matrix Metalloproteinase 2 Expression in Mucoepidermoid Carcinoma and Adenoid Cystic Carcinoma of Salivary Glands.

Statement of the Problem: The tumor suppressor role of myoepithelial cells and related mechanisms in breast tumors are well understood. However, the role of these cells in tumors of salivary glands is debatable.Purpose: The present study was designed to determine the expression of p63, mammary serine protease inhibitor (maspin) and matrix metalloproteinase 2 (MMP-2) in mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ADCC) of salivary glands due to various cellular differentiation and structure. The association between the expression of these markers and clinicopathologic features and myoepithelial differentiation were also evaluated.Materials and Method: P63, maspin, and MMP-2 expression were immunohistochemically studied in 67 cases including35 cases of MEC and 32 cases of ADCC. The smooth muscle actin (SMA) staining was also applied to confirm the presence of myoepithelial differentiation. Data was analyzed using Chi-square test, Mann-Whitney U test and t-test.Results: The expression of p63 (p= 0.009) and maspin (p= 0.012) significantly differed between the study groups. P63 positive cells in MEC were negative for SMA staining in contrast to ADCC. Furthermore, the expression of P63 (p= 0.045) and maspin (p= 0.019) significantly and inversely correlated with histologic grade in ADCC. Likewise, positive significant correlation was detected between histologic grade and expression of P63 (p= 0.018) and MMP-2 (p= 0.003) in MEC samples.Conclusion: Our findings showed that MEC is devoid of myoepithelial cells. The difference in expression of P63 and maspin in ADCC and MEC highlighted the role and presence of myoepithelial cells in ADCC. Indeed, the high expression of P63 and maspin in well-differentiated ADCCs suggests the tumor suppressor effect of myoepithelial cells. Considering the association between the evaluated markers and histological grade, p63 in both tumors, maspin in ADCC and MMP-2 in MEC may be efficient predictors of clinical behavior.

Developmental patterns in human blood\u2013brain barrier and blood\u2013cerebrospinal fluid barrier ABC\xa0drug transporter expression

When drugs exert their effects in the brain, linear extrapolation of doses from adults could be harmful for children as the blood–brain barrier (BBB) and blood–CSF barrier (BCSFB) function is still immature. More specifically, age-related variation in membrane transporters may impact brain disposition. As human data on brain transporter expression is scarce, age dependent [gestational age (GA), postnatal age (PNA), and postmenstrual age (PMA)] variation in immunohistochemical localization and staining intensity of the ABC transporters P-glycoprotein (Pgp), breast cancer resistance protein (BCRP), and multidrug resistance-associated proteins 1, 2, 4, and 5 (MRP1/2/4/5) was investigated. Post mortem brain cortical and ventricular tissue was derived from 23 fetuses (GA range 12.9–39 weeks), 17 neonates (GA range 24.6–41.3 weeks, PNA range 0.004–3.5 weeks), 8 children (PNA range 0.1–3 years), and 4 adults who died from a wide variety of underlying conditions. In brain cortical BBB, immunostaining increased with age for Pgp and BCRP, while in contrast, MRP1 and MRP2 staining intensity appeared higher in fetuses, neonates, and children, as compared to adults. BCSFB was positively stained for Pgp, MRP1, and MRP2 and appeared stable across age, while BCRP was not detected. MRP4 and MRP5 were not detected in BBB or BCSFB. In conclusion, human BBB and BCSFB ABC membrane transporters show brain location and transporter-specific maturation.

Dual-Energy CT Follow-Up After Stroke Thrombolysis Alters Assessment of Hemorrhagic Complications.

Background and Purpose: We aimed to determine whether dual-energy CT (DECT) follow-up can differentiate contrast staining (CS) from intracranial hemorrhage (ICH) in stroke patients treated with intravenous thrombolysis (IVT), who had undergone acute stroke imaging using CT angiography (CTA), and CT perfusion (CTP).Materials and Methods: Between November 2012 and January 2018, 168 patients at our comprehensive stroke center underwent DECT follow-up within 36 h after IVT and acute CTA with or without CTP but did not receive intra-arterial imaging or treatment. Two independent readers evaluated plain monochromatic CT (pCT) alone and compared this with a second reading of a combined DECT approach using pCT and water- and iodine-weighted images, establishing and grading the ICH diagnosis, per Heidelberg and Safe Implementation of Treatments in Stroke Monitoring Study (SITS-MOST) classifications.Results: On pCT alone within 36 h, 31/168 (18.5%) patients had findings diagnosed as ICH. Using combined DECT (cDECT) changed ICH diagnosis to “CS only” in 3/168 (1.8%) patients, constituting 3/31 (9.7%) of cases with initially pCT-diagnosed ICH. These three cases had pCT diagnoses of one SAH, one minor, and one more extensive petechial hemorrhage (hemorrhagic infarction types 1 and 2), respectively. pCT alone had a 100% sensitivity, 98% specificity, 90% positive predictive value (PPV), 100% negative predictive value (NPV), and 98% accuracy for any ICH, compared to the cDECT. Inter-reader agreement for ICH classification using pCT compared to DECT was weighted kappa 0.92 (95% CI 0.87–0.98) vs. 0.91 (0.85–0.95).Conclusion: Compared to pCT, DECT within 36 h after IV thrombolysis for acute ischemic stroke, changes the radiological diagnosis of post-treatment ICH to “CS only” in a small proportion of patients. Studies are warranted of whether the altered radiological reports have an impact on patient management, for example initiation timing of antithrombotic secondary prevention.

Effect of concentration and staining duration of iodine contrast applied to study the masticatory muscle of Wistar rats in micro‐CT images

The challenge to study the anatomy of the muscular system is to replace destructive methods such as macroscopic dissection with non‐destructive methods involving magnetic resonance imaging and computed microtomography (micro‐CT). The aim of this study was to evaluate the effect of concentration and staining duration of iodine contrast applied to study the masticatory muscle of Wistar rats in micro‐CT images. Fifteen male Wistar rats (Rattus norvegicus albinus), 2 months old (200–250g) from CEMIB‐UNICAMP were used. After euthanasia, the animals were randomly assigned to the experiments in 3 groups of 5 rats each, with the iodine contrast solutions of 3%, 5% and 10%. Each group was subdivided into 3 subgroups according to the staining duration: 7 days, 15 days and 30 days. The pieces were scanned on a 1174 Skyscan microtomograph (Bruker, Belgium) with a voltage of 50 Kv and amperage of 800 μA at the Piracicaba Dental School‐UNICAMP. The scanning of the pieces was done with a pixel dimension equal to 31 μm. After scanning, the images were exported to the software NRecon Reconstruction (Bruker, Belgium) in which they were reconstructed three‐dimensionally in axial sections presenting the x‐ray attenuation coefficients with values relative to the muscle structure reinforced by contrast. The reconstructed images were exported to the software Materialise MIMICS v18 (Materialise, Belgium) to evaluate the anatomical characteristics as well as the density of masticatory muscles. The muscles observed were: Temporal, Masseter (superficial part), Masseter (deep part), External pterygoid, Internal pterygoid and Zigomaticomandibular. These parameters were evaluated in each piece to compare the effects of different contrast concentration and staining duration. The 5% concentration showed better characterization of muscle groups, regardless of the period. At 5%, the 30‐day period showed better definition of muscle fibers. The 3% concentration presented only muscle mass and its contours, but there was no definition in the image that could differentiate each muscle. In the group with a concentration of 10%, contrast enhancement was observed only on the muscular surfaces. Thus, the solution concentration was the most effective parameter to stain the muscle fibers. The preparation and application protocol of iodine‐based contrast solution was most effective at 5% concentration with 30 days action.Support or Funding InformationNational Council for Scientific and Technological Development (PIBIC/CNPq).

Abstract WP65: Clinical and Radiographic Characterization of Cerebral Hyperdensities on Post-thrombectomy Conventional Non-contrast Ct Brain: Differentiating Between Contrast Staining and Post-thrombectomy Hemorrhage

Background: Post-interventional cerebral hyperdensities (PCHD) are present 31.2 to 87.5% of the time on post-thrombectomy (PT) CT. It can be difficult for radiologists to differentiate if PCHD represents intracerebral hemorrhage (ICH) or contrast staining using conventional CT. The ability to accurately determine the etiology of PCHD may be important for a patient’s outcome. Methods: We retrospectively investigated clinical risk factors, imaging findings, and interventional technique of patients who had a thrombectomy from 2011-2017 (n=238) at a Comprehensive Stroke Center. 112 patients with anterior circulation infarcts and immediate PT CTs as well as either a PT MRI or follow-up CT within 48 hours were included. Two experienced neuroradiologists interpreted all imaging. Baseline demographics and imaging characteristics were collected. The presence of ICH was determined by dephasing on gradient echo or by its persistence > 2 days on repeat CT. Chi-square and Fisher’s exact tests were used for statistical significance, and logistic regression to determine risk estimates. Results: 84% of patients had PCHD, of which 56% had ICH. Patients had similar demographics (ICH: median age 69, 47.5% female; non-ICH: median age 71, 42.5% female). Higher pre-thrombectomy ASPECTS score (OR 0.62, p < 0.05) decreased the risk of ICH, and higher Hounsfield units (HU) of PCHD both on immediate (OR 1.04, p < 0.05) and intermediate (OR 1.1, p < 0.0005) PT CT increased the risk of ICH. PCHDs in the deep grey matter (OR 2.84, p < 0.05) and demonstrating a confluent pattern (OR 3.9 p < 0.05) increased the likelihood of ICH. 10% increase risk of ICH was seen for every HU increase in density on PT CT at 24 or 48 hours. A 50% decrease in ICH was observed for each unit increase of the pre-thrombectomy ASPECTS score. ROC revealed the optimal cut-off for predicted probability as 0.64, sensitivity 70.2% and specificity 69.2%. The AUC for the predicted model was 0.84 (95%CI= (0.75- 0.92, p <0.0001). Conclusion: Several imaging characteristics of PCHDs and ASPECTS score can help differentiate between the PT ICH and contrast staining. Application of these variables to patients in the immediate PT period may change clinical management.

Prediction of Hemorrhage after Successful Recanalization in Patients with Acute Ischemic Stroke: Improved Risk Stratification Using Dual-Energy CT Parenchymal Iodine Concentration Ratio Relative to the Superior Sagittal Sinus.

Brain parenchymal hyperdensity on postthrombectomy CT in patients with acute stroke can be due to hemorrhage and/or contrast staining. We aimed to determine whether iodine concentration within contrast-stained parenchyma compared with an internal reference in the superior sagittal sinus on dual-energy CT could predict subsequent intracerebral hemorrhage. Seventy-one patients with small infarct cores (ASPECTS ≥ 7) and good endovascular recanalization (modified TICI 2b or 3) for anterior circulation large-vessel occlusion were included. Brain parenchymal iodine concentration as per dual-energy CT and the percentage of contrast staining relative to the superior sagittal sinus were recorded and correlated with the development of intracerebral hemorrhage using Mann-Whitney U and Fisher exact tests. Forty-three of 71 patients had parenchymal hyperdensity on initial dual-energy CT. The median relative iodine concentration compared with the superior sagittal sinus was significantly higher in those with subsequent intracerebral hemorrhage (137.9% versus 109.2%, P = .007). By means of receiver operating characteristic analysis, a cutoff value of 100% (iodine concentration relative to the superior sagittal sinus) enabled identification of patients going on to develop intracerebral hemorrhage with 94.75% sensitivity, 43.4% specificity, and a likelihood ratio of 1.71. Within our cohort of patients, the relative percentage of iodine concentration at dual-energy CT compared with the superior sagittal sinus was a reliable predictor of intracerebral hemorrhage development and may be a useful imaging biomarker for risk stratification after endovascular treatment.

The Nasolabial Fold: A Micro-Computed Tomography Study.

The nasolabial fold is known to be a challenging midface feature for aesthetic physicians. However, the steric conformation of the structures related to the nasolabial fold has remained undefined because the composition and topography of this region are highly intricate. Therefore, this study aimed to clarify the three-dimensional structures of the nasolabial fold using micro-computed tomography and verify their detailed composition by means of histologic observation. Twenty-four specimens were collected from the area beside the alae nasi to the area above the oral angle of 12 cadavers (mean age, 80.3 years) bilaterally. Twelve specimens were evaluated by means of phosphotungstic acid contrast staining, and the rest were evaluated by means of histologic staining. All specimens were divided into three regions and analyzed comprehensively. The medial region of the nasolabial fold had dense irregular connective tissue intermingled with muscle fibers; the lateral region of the nasolabial fold had numerous fibrous septa with abundant adipose tissue. The levator labii alaeque nasi and the zygomaticus minor were attached to the medial part of the nasolabial fold, and the fascial septa were intermittently tethered to the dermis, lateral to the nasolabial fold. The extension of the adipose tissue within the fascial septa was limited by the lateral border of the muscle attachment. Dimensional and distributional alterations of the adipose tissues with senescence could render the nasolabial fold deeper by increasing the depth of the subcutaneous layer, lateral to the fold. Thus, to ameliorate the fold, the adipose tissue, lateral to the fold, or the muscle traction, medial to the fold, should be altered.

275 A Novel Method for Detecting Coronary Artery Dissection Using Computed Tomography Coronary Angiography

Spontaneous coronary artery dissection (SCAD) is an uncommon and underdiagnosed condition, which is increasingly recognised as an important cause of myocardial infarction. Computed tomography coronary angiography (CTCA) is an emerging non-invasive tool for assessment of SCAD, not yet recommended as first-line imaging due to its lower temporal and spatial resolution compared to catheter coronary angiography. A 34-year-old female with no medical history presented with chest pain and inferolateral ST-segment elevation on electrocardiogram (ECG). Catheter coronary angiography revealed coronary artery dissection involving the left main, left anterior descending and circumflex arteries. Computed tomography angiogram revealed multifocal carotid and vertebral artery dissection, with renal artery beading, suggesting fibromuscular dysplasia. A follow-up CTCA was performed using a prospective ECG-gated dual source high-pitch helical scanner (Siemens, High Definition Flash, Forchheim, Germany). The scan was repeated 13 seconds later without further contrast. This “double-scan” had the unique effect of showing contrast “staining” in the false lumen of the dissection, occurring as a result of residual contrast not yet washed out from the first scan. The findings of this “double-scan” technique appears analogous to the contrast staining of the false lumen observed on catheter coronary angiography. Depending on the type of scanner and mode of use, obtaining more than two scans following the contrast bolus may be possible. However, the timing of repeat scans may need to vary depending on the flow characteristics of false lumen filling and haemodynamics. Further research is required to determine how to best apply this novel utility.

Combining 3D heads-up display viewing system and intraoperative optical coherence tomography-assisted vitrectomy for myopic foveoschisis

Objective To observe the clinical efficacy of digital 3D heads-up display viewing system(3D viewing system) and intraoperative OCT (iOCT) in vitrectomy for myopic foveoschisis (MF). Methods A retrospective, consecutive case series. From October 2018 to May 2019, Nineteen eyes of 19 consecutive patients with MF diagnosed in Xiamen Eye Center of Xiamen University who underwent vitrectomy were included in this study. There were 7 males and 12 females, with the mean age of 54.47±11.38 years. The average axial length was 30.40±2.30 mm, the mean logMAR BCVA was 0.56±0.31, the mean central foveal thickness (CFT) was 317.80±151.9.32 μm, the mean max retinal thickness (maxRT) was 556.7±143.7 μm. All the surgeries performed combined with 3D viewing system with iOCT. The standard 25G pars planar vitrectomy were performed with removing the posterior vitreous and indocyanine green (ICG) staining of internal limiting membrane (ILM) and air-fluid exchange. Thirteen of 19 eyes underwent fovea-sparing ILM peeling and the other 6 eyes not. The average follow-up was 4.2±1.4 months. All the patients were on regular follow-up to document the changes on BCVA, anatomical changes in macula, CFT and maxRT. Paired t test was used to compare BCVA, CFT and maxRT before and after surgery. Results The fine images of macula were clearly shown on the 3D viewing system in all eyes. The electronic green filter enhanced the contrast sensitivity of ICG stained images. Clear images of macula were captured by iOCT in all eyes. The average surgical time was 35.5±8.2 min. On the last follow-up, 16 of 19 eyes with MF resolved. The mean CFT was 178.5±103.5 μm, the maxRT was 341.8±83.8.16 μm, and the mean logMAR BCVA was 0.35±0.22. The differences of CFT, maxRT and logMAR BCVA before and after surgery were statistically significant (t=4.181, 7.154, 5.129; P<0.001). Minimal invisible full thickness macular hole were detected in 2 eyes by iOCT and repaired with auto serum or ILM flap covering. There was no complication associated with the 3D viewing system. Conclusions 3D viewing system provides improved contrast and crystal clear macular image stain with ICG in pathological myopia. iOCT can detect the minimal invisible full thickness macular hole during surgery. Both may contribute to improved MF closure rate and BCVA. Key words: Vitreoretinal surgery/instrumentation; Tomography, optical coherence; Retinoschisis/surgery; Myopiadegenerative/complications; 3D heads-up display viewing system

Activated but Not Quiescent Hematopoietic Stem Cells Rely Readily on Glycolysis As Their Main Source of Energy

Elucidating mechanisms that regulate hematopoietic stem cells (HSCs) quiescence is critical for improving bone marrow transplantation. It is postulated that quiescent HSCs rely mostly on glycolysis rather than mitochondrial oxidative phosphorylation (OXPHOS) as their energy source. We have identified a population of HSCs with low mitochondrial activity (LSKCD150+CD48- within the 25% lowest mitochondrial membrane potential; MMP-low) that we show are highly enriched in quiescent HSCs (~95% ±2.65 in G0) as measured by pyronin Y/Hoechst staining in contrast to LSKCD150+CD48- within 25% highest MMP (MMP-high) that are in majority in G1/S/G2/M phase of cell cycle (55.4%±16; p&amp;lt;0.05; n=3). MMP-low HSCs exhibit greater in vivo competitive repopulation ability (3.7 fold; p=0.021; n=10 mice) at 16 weeks as compared to MMP-high fractions, show higher self renewal ability and are enriched in label-retaining H2B-GFP+ cells (~3 fold; p&amp;lt;0.01; n=3). Conversely, label-retaining GFP+HSCs maintain lower MMP than non-label-retaining cells. Altogether these results reinforce the notion that MMP-low HSCs are quiescent whereas MMP-high HSCs are primed/activated. Using single cell RNA-sequencing (scRNA-seq) analysis to interrogate the transcriptome by a Fluidigm C1 platform within MMP-high versus MMP-low HSCs we found major metabolic pathways including OXPHOS, exhibit significantly greater expression within the MMP-high than in the MMP-low HSC fraction. Seahorse analysis confirmed that MMP-high but not -low hematopoietic stem and progenitor cells (HSPCs) use OXPHOS as their source of energy (3.9 fold; n=16 mice). Unexpectedly, glycolytic gene expression was also enriched in the primed MMP-high HSCs and relatively low in quiescent MMP-low HSCs. qRT-PCR analysis further confirmed that the expression of glycolytic enzymes and other genes including glucose transporter 1 (Glut1, slc2a1) that is the main glucose transporter on HSCs is greater in MMP-high relative to -low HSCs. These unforeseen findings raised the potential that despite the current consensus in HSC biology, glycolysis may more readily support activated rather than quiescent HSCs. We thus measured the glucose uptake in MMP-low vs -high HSCs under metabolic (pyruvate, glucose and glutamine)-restricted conditions. Using 2NBDG, a fluorescently tagged glucose analog, we found that MMP-high HSCs uptake 3.3-fold more glucose and contained three times more 2NBDG+ cells as compared to MMP-low HSCs (p&amp;lt;0.001 for each; n=3). Pharmacological inhibition of Glut1 reduced glucose uptake in MMP-high but not -low HSCs suggesting the specific sensitivity of MMP-high HSCs to the glucose inhibition. In addition, activation of tricarboxylic acid cycle TCA cycle with combined methyl-pyruvate and dimethyl-alpha-ketoglutarate led to a greater glucose uptake (~3.5 fold) in MMP-high as compared to MMP low HSCs (~2.2 fold; p&amp;lt;0.0001). To address the degree to which glycolysis is necessary, FACS-purified MMP-low and -high HSCs were incubated with 2-Deoxy D-Glucose (2DG) - a glucose analog - that inhibits glycolysis via its action on hexokinase. While glucose deprivation with 50 mM dose of 2DG within 12 hours did not have much effect on MMP-low HSCs, over 60% of MMP-high HSCs died (p&amp;lt;0.001; n=3), suggesting that MMP-high but not -low HSCs rely readily on glycolysis for their survival. Also, the inhibition of mitochondrial transport of pyruvate that is the end product of glycolysis (α-cyano-4-hydroxycinnamate (CHC)), decreased survival in MMP-high HSCs by 80% with negligible effect on MMP-low HSCs (p&amp;lt;0.01; n=3). Finally 50 FACS-purified HSCs (LSKCD150+CD48-MMP-low or -high) were transplanted in lethally irradiated mice along with 200,000 unfractionated bone marrow cells in a competitive repopulation assay and mice were subsequently treated with 2DG or control vehicle every other day for two weeks. Two months later, 2DG treatment led to significantly enhanced reconstitution levels in MMP-high HSCs with no or little effect on MMP low reconstitution levels (ongoing). These combined results suggest that primed MMP-high rather than quiescent MMP-low HSCs rely on glycolysis as their main source of energy. These findings are consistent with the concept that glycolysis is key in sustaining rapidly dividing cells such as embryonic stem cells and cancer cells. Disclosures Ghaffari: Rubius Therapeutics: Consultancy.

Characteristics of myocardial tissue staining and lesion creation with an infusion-needle ablation catheter for the treatment of ventricular tachycardia in humans

Intramural substrate causing ventricular tachycardia can be targeted by radiofrequency (RF) infusion-needle catheter ablation. The purpose of the study was to assess fluid distribution within the myocardium after needle-ablation catheter infusion and its evidence to RF lesion creation. In 25 patients (21 (84%) male; 67 ± 9 years; 8 (32%) with ischemic cardiomyopathy) intramural ablation of ventricular tachycardia was performed with a needle catheter. Fluoroscopic images of myocardial staining patterns produced by pre-RF saline/contrast infusion were analyzed. Lesion creation was defined as tissue inexcitability to high-output needle pacing. Data from 155 sites were eligible for analysis. Tissue staining was evident in 111 (72%) and absent in 44 (28%). The stain shapes were variable, with average dimensions of 20 ± 10 × 8 ± 4 mm with an area of 68 ± 58 mm2. Round/oval-shaped stains were most common (62 [56%]), while multisegmented (36[32%]) and long flat (13 [12%]) configurations were less frequent. Evidence of staining was associated with evidence of lesion creation (92/111 (83%) vs 17/44 (39%); P≤.0001). Contrast staining around the needle was present in 50%, usually had blurred margins, and was associated with lesion creation. When staining extended well beyond the needle, the margins were often sharp, suggesting dissection through tissue planes, and lesion creation tended to be less effective. With infusion-needle ablation, preablation injection of contrast can help confirm an intramural position and predict lesion creation. Tissue diffusion patterns vary markedly, and studies to assess its relation to tissue architecture and ablation lesion geometry warrants further investigation. The findings also have implications for the injection of therapeutic agents into the regions of scar.

Dual energy CT after stroke thrombectomy alters assessment of hemorrhagic complications.

To determine whether dual energy CT with a combined approach (cDECT) using a plain noncontrast monochromatic CT (pCT), a water-weighted image after iodine removal, and an iodine-weighted image changes the diagnosis and classification of intracranial hemorrhage (ICH) after endovascular thrombectomy (EVT) in acute ischemic stroke compared to a pCT image alone without separate water and iodine weighting. During 2012 to 2016, 372 patients at our comprehensive stroke center underwent DECT scans within 36 hours after EVT. Two readers evaluated pCT compared to a second reading with cDECT, establishing the diagnosis of ICH and grading it per the Heidelberg and Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST) classifications. Using cDECT changed the ICH diagnosis to contrast staining only in 34% (52 of 152), modified the ICH grade in 10% (15 of 152), and diagnosed initially undetected ICH in 2% (5 of 220). pCT alone had 95% sensitivity, 80% specificity, 66% positive predictive value, 98% negative predictive value, and 85% accuracy for ICH compared to cDECT. Interreader agreement on the presence of ICH increased with cDECT compared to pCT (Cohen κ = 0.77 [95% confidence interval 0.69-0.84] vs 0.68 [0.61-0.76]). cDECT within 36 hours after EVT changes the radiologic report regarding posttreatment ICH in a considerable proportion of patients undergoing EVT compared to pCT alone. This could affect decision-making regarding monitoring, secondary prevention, and prognostication. The cDECT scan could improve the interpretation consistency of high-attenuating changes on post-EVT images.

Vascular Imaging: Utilization of Dual-Energy Computed Tomography

The goal of this review is to present a concise summary of the current literature on the use of dual-energy computed tomography (DECT) for vascular imaging. DECT techniques have shown significant promise and useful applications for the detection of subtle pulmonary embolism, intramural hematoma, active bleeding, and differentiation of bleed from contrast staining in the brain, with potentially less radiation and improved accuracy. Vascular imaging with DECT has many new applications through enhanced technology and postprocessing algorithms.

Substrate-Assisted Visualization of Surfactant Micelles via Transmission Electron Microscopy

The visualization of the micellar morphological evolution for surfactant has drawn much attention due to its self-assemble ability to fold into various structures. However, the direct observation of the soft materials with low atomic number has been hampered because of the poor scattering contrast and complex staining process by the traditional transmission electron microscopy (TEM) techniques. Herein, we reported a novel strategy to the visualization of surfactant micelles with the assistance of layered double hydroxides (LDHs) via TEM. Owing to the uniformly distributed metal ions and positive charges in the LDHs, the surfactant at the micelle-water interface reacted with LDHs to form a stabilized architecture through electrostatic and hydrogen-bond interactions. The morphologies of the surfactant can be clearly observed through the surfactant-LDHs architectures, exhibiting high contrast by TEM techniques. Significantly, the micellar evolutions involving the spherical, rodlike, and wormlike shapes were successfully distinguished. Our results may provide great possibilities and inspirations for the visualization for morphology of soft matters.

TCTAP C-208 Appearance of Peri-stent Contrast Staining in Everolimus Eluting Stent After Target Vessel Revascularization

### Patient Initials or Identifier Number T.T ### Relevant Clinical History and Physical Exam An 80 years old man, who had a history of everolimus-eluting stent (EES) implantation in the proximal left anterior descending artery (LAD) under the diagnosis of acute coronary syndrome 7 years ago,

Reproducibility of the Recursive Segmentation Technique for Creating 3D Models of Thin Connective Tissue Structures from MRI Data: The Myosepta of Lampreys (Agnatha) as an Example

The analysis, measuring, and recording of anatomical structures by means of dissection and other destructive techniques introduces inaccuracies due to the risk of damaging the original organization of a body's tissues. More so than other tissues, thin connective tissues are especially susceptible to breakage and distortions. MRI is the method of choice for visualizing and identifying connective tissue structures in 3D without the need for contrast staining, which dehydrates and shrinks soft tissues. The visualization of MRI data, however, comes with their own challenges because optimizing image resolution as well as contrast resolution in a particular data set generally results in non‐cubic voxels. Optimizing image resolution requires minimizing pixel size in the viewing plane, whereas optimizing contrast resolution among pixels in the viewing plane requires maximizing the number of hydrogen atoms and, hence, the voxel volume for a more accurate statistical summation of relaxing hydrogen atoms. The latter would create a non‐cubic voxel with a greater depth than the side length of the pixel in the viewing plane. Non‐cubic voxels, however, present a special challenge for building realistic 3D models based on MRI data, in particular for complexly configured thin connective tissue structures that are thinner than a voxel and, therefore, may not be discriminated from the surrounding tissue along their entire course. Recursive segmentation is a technique that allows the reconstruction of such structures in their entirety by using more than one MRI scan of the same specimen in the same position. While most segmentation can usually be done from 3D MRI scans, some portions of the structure may not have enough contrast resolution to be identified because of the almost cubic voxels. For such a portion, its segmentation from a 2D MRI scan with greater contrast resolution in the viewing plane, although lower image resolution in the planes perpendicular to the viewing plane, can serve as a scaffold for guiding the segmentation of the portion that is invisible in the 3D MRI scan. This technique allows the reconstruction of a realistic (“realitätsgetreues”) 3D model of the entire structure. The recursive technique requires skill and anatomical knowledge of the structures to be segmented by the operator and, therefore, needed to be tested as to its efficacy, reliability, and reproducibility even when used by different operators, some of whom may be less familiar with the anatomy of the structures and the segmentation software. By having a novice operator who is unfamiliar with the anatomy of lampreys execute the segmentation of myosepta with and without the help of the recursive technique, we were able to demonstrate that recursive segmentation using both 2D and 3D MRI data sets is essential to creating accurate and realistic 3D models of thin connective tissue structures. Realistic 3D models of myosepta of lampreys and other piscine vertebrates are necessary prerequisites for an elucidation of the biomechanics underlying undulatory swimming behavior.Support or Funding InformationLSU FoundationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Impact of mir21 Expression in Chronic Lung Allograft Dysfunction after Lung Transplantation

Purpose Long-term survival after lung transplantation is still limited by the development of chronic lung allograft dysfunction (CLAD), presenting either as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). Epithelial-to-mesenchymal transition (EMT) is recognized as one of the pathogenic processes contributing to CLAD. MiR-21 is a post-translational regulator of several pathways of fibrosis and has recently been related to EMT. In this study we aimed to characterize miR-21 expression and other markers of EMT in lung tissue of BOS and RAS patients. Methods Formalin-fixed paraffin-embedded tissue of 17 BOS patients and 7 RAS patients undergoing a lung retransplantation due to CLAD and 5 normal lung tissue samples (control) were evaluated for the expression following markers: vimentin, notch intracellular domain (NICD), p-SMAD 2/3, β-catenin, and E-cadherin. Slides were additionally stained for miR-21 by in situ hybridization (ISH). Expression of respective markers were graded in a semi-quantified manner by two blinded pathologists. Results Vimentin, NICD, p-SMAD 2/3 were positive in 13 (77%), 12 (71%), and 7 (42%) BOS patients, and in 5 (71%), 4 (57%) and 4 (57%) RAS patients, respectively. In contrast, β-catenin and E-cadherin staining were consistently negative in both groups. In comparision, no significant difference was found between BOS and RAS regarding these markers. MiR-21 expression was positive in 5 (30%) BOS cases and 6 (86%) RAS cases. The rate of miR-21 expression was significantly higher in RAS than in BOS (p=0.01). MiR-21 expression was associated with significant shorter freedom to BOS (11.5 vs 46.0 months, p=0.001, Figure 1), but had no impact on the development of RAS. Conclusion This first preliminary study could identify miR-21 as a possible biomarker and therapeutic target of CLAD and mirR-21 expression was related to worse outcomes in BOS cases. Further research is necessary to validate these findings in a larger cohort of patients.

Glomerular membrane attack complex is not a reliable marker of ongoing C5 activation in lupus nephritis

Complement plays an important role in the pathogenesis of lupus nephritis (LN). With the emergence of therapeutic complement inhibition, there is a need to identify patients in whom complement-driven inflammation is a major cause of kidney injury in LN. Clinical and histopathological data were obtained retrospectively from 57 biopsies with class III, IV, and V LN. Biopsies were stained for complement components C9, C5b-9, C3c, and C3d and for the macrophage marker CD68. C9 and C5b-9 staining were highly correlated (r = 0.92 in the capillary wall). C5b-9 staining was detected in the mesangium and/or capillary wall of both active and chronic proliferative LN in all but one biopsy and in the capillary wall of class V LN in all biopsies. C5b-9 staining intensity in the tubular basement membrane correlated with markers of tubulointerstitial damage, and more intense capillary wall C5b-9 staining was significantly associated with nonresponse to conventional treatment. Glomerular C5b-9 staining intensity did not differ between active and chronic disease; in contrast, C3c and CD68 staining were associated with active disease. Evaluation of serial biopsies and comparison of staining in active and chronic LN demonstrated that C5b-9 staining persisted for months to years. These results suggest that C5b-9 staining is almost always present in LN, resolves slowly, and is not a reliable marker of ongoing glomerular C5 activation. This limits the utility of C5b-9 staining to identify patients who are most likely to benefit from C5 inhibition.