Normal Signal Intensity Research Articles

3:09 PM Abstract No. 128 Development of real-time optical image-assessed thermal ablation of hepatic tumor

To investigate the feasibility of using indocyanine green (ICG)-based optical imaging to instantly assess the effective radiofrequency ablation (RFA) on VX2 tumor cells, towards the development of intratumoral real-time optical imaging-guided RFA of larger tumors. We first optimized the uptake characteristics of a clinically applicable optical contrast, indocyanine green (ICG), by VX2 tumor cells. 1×104 VX2 cells in each of different cell groups were treated with various ICG concentrations from 0 to 125 μg/mL, over incubation times from 0 min to 48 hours. Then, in comparison to ICG solution-only, ICG-labeled VX2 cells were treated by thermal ablation at 80 °C for 30 minutes. ICG in cells were subsequently qualitatively and quantitatively evaluated by fluorescence microscopy and optical imaging. The optimization of the ICG concentration demonstrated a linear increase of fluorescent signal intensities (SI), with the peak SI at 100 μg/mL of ICG, starting at the time point of 24 hours post-ICG labeling. Both the fluorescent SIs of ICG-only and ICG-labeled VX2 cell groups were significantly decreased after the thermal ablation treatment (For ICG solution: average SI pretreatment vs. SI posttreatment = 11075.2 ± 1060.9 count vs. 4681.1 ± 442.1 count, P <0.001; and for ICG-labeled VX2 cells: 926.2 ± 197.1 count vs. 301.4 ± 53.9 count, P <0.001). This study demonstrated the feasibility of using indocyanine green (ICG)-based optical imaging to evaluate the instant treatment effect of thermal ablation on VX2 tumor cells, which has encouraged the further on-going studies for developing the new interventional molecular imaging technique to ensure the complete removal of larger tumors during a single RFA session.

Quantitative DCE-MRI demonstrates increased blood perfusion in Hoffa\u2019s fat pad signal abnormalities in knee osteoarthritis, but not in patellofemoral pain

ObjectiveInfrapatellar fat pad (IPFP) fat-suppressed T2 (T2FS) hyperintense regions on MRI are an important imaging feature of knee osteoarthritis (OA) and are thought to represent inflammation. These regions are also common in non-OA subjects, and may not always be linked to inflammation. Our aim was to evaluate quantitative blood perfusion parameters, as surrogate measure of inflammation, within T2FS-hyperintense regions in patients with OA, with patellofemoral pain (PFP) (supposed OA precursor), and control subjects.MethodsTwenty-two knee OA patients, 35 PFP patients and 43 healthy controls were included and underwent MRI, comprising T2 and DCE-MRI sequences. T2FS-hyperintense IPFP regions were delineated and a reference region was drawn in adjacent IPFP tissue with normal signal intensity. After fitting the extended Tofts pharmacokinetic model, quantitative DCE-MRI perfusion parameters were compared between the two regions within subjects in each subgroup, using a paired Wilcoxon signed-rank test.ResultsT2FS-hyperintense IPFP regions were present in 16 of 22 (73%) OA patients, 13 of 35 (37%) PFP patients, and 14 of 43 (33%) controls. DCE-MRI perfusion parameters were significantly different between regions with and without a T2FS-hyperintense signal in OA patients, demonstrating higher Ktrans compared to normal IFPF tissue (0.039 min−1 versus 0.025 min−1, p = 0.017) and higher Ve (0.157 versus 0.119, p = 0.010). For PFP patients and controls no significant differences were found.ConclusionsIPFP T2FS-hyperintense regions are associated with higher perfusion in knee OA patients in contrast to identically appearing regions in PFP patients and controls, pointing towards an inflammatory pathogenesis in OA only.Key Points• Morphologically identical appearing T2FS-hyperintense infrapatellar fat pad regions show different perfusion in healthy subjects, subjects with patellofemoral pain, and subjects with knee osteoarthritis.• Elevated DCE-MRI perfusion parameters within T2FS-hyperintense infrapatellar fat pad regions in patients with osteoarthritis suggest an inflammatory pathogenesis in osteoarthritis, but not in patellofemoral pain and healthy subjects.

Normal size of the fetal adrenal gland on prenatal magnetic resonance imaging.

The adrenal gland plays a vital role in fetal growth. Many disease states such as congenital adrenal hyperplasia, hemorrhage and tumors can lead to morphological changes in the gland. Ultrasound measurements of normal adrenal sizes in the fetus reported in the literature have shown a trend of increasing size with gestational age. There is no literature available on standard fetal adrenal sizes or detailed appearance by fetal MRI. The purpose of this study was to provide MR data on the size and signal characteristics of the fetal adrenal gland throughout the second and third trimesters. In this retrospective review, we selected 185 prenatal MRIs obtained from Jan. 1, 2014, to May 31, 2017, with normal abdominal findings for inclusion. The adrenal glands were identified in coronal, sagittal or axial T2-W planes and coronal T1-W plane when available. We measured the length and thickness of the medial and lateral limbs of the right and left adrenal glands and recorded signal intensity on T1-W and T2-W sequences, gender and gestational age in each case. The gestational age (GA) ranged 18-37weeks. Visibility of the adrenal glands on T2-W images was high (90.3-97.2%) up to 30weeks of GA but declined afterward (47.5-62.2% at 31-37weeks). Visibility on T1-W images increased with GA, ranging from 21.4% visibility at 18-22weeks and increasing to 40% at 35-37weeks. Mean lengths of the adrenal gland limbs steadily increased from 8.2mm at 18-22weeks to 11.0mm at 35-37weeks. In the second trimester, adrenal glands were low in signal intensity on T2-W images and were surrounded by hyperintense perirenal fatty tissue. In the third trimester, the glands became less distinct, with increasing signal and obliteration of perirenal tissue. The glands were moderately hyperintense on T1-W images throughout pregnancy, with increasing visibility as pregnancy progressed. Normal sizes and signal intensities for adrenal glands are reported. Visibility of adrenal glands on T2-W images was 90.3-97.2% up to 30weeks but declined thereafter. Visibility on T1-W images increased in the third trimester. Adrenal gland sizes increased with gestational age.

Quantification of tumor burden in multiple myeloma by atlas-based semi-automatic segmentation of WB-DWI

BackgroundWhole-body diffusion weighted imaging (WB-DWI) has proven value to detect multiple myeloma (MM) lesions. However, the large volume of imaging data and the presence of numerous lesions makes the reading process challenging. The aim of the current study was to develop a semi-automatic lesion segmentation algorithm for WB-DWI images in MM patients and to evaluate this smart-algorithm (SA) performance by comparing it to the manual segmentations performed by radiologists.MethodsAn atlas-based segmentation was developed to remove the high-signal intensity normal tissues on WB-DWI and to restrict the lesion area to the skeleton. Then, an outlier threshold-based segmentation was applied to WB-DWI images, and the segmented area’s signal intensity was compared to the average signal intensity of a low-fat muscle on T1-weighted images. This method was validated in 22 whole-body DWI images of patients diagnosed with MM. Dice similarity coefficient (DSC), sensitivity and positive predictive value (PPV) were computed to evaluate the SA performance against the gold standard (GS) and to compare with the radiologists. A non-parametric Wilcoxon test was also performed. Apparent diffusion coefficient (ADC) histogram metrics and lesion volume were extracted for the GS segmentation and for the correctly identified lesions by SA and their correlation was assessed.ResultsThe mean inter-radiologists DSC was 0.323 ± 0.268. The SA vs GS achieved a DSC of 0.274 ± 0.227, sensitivity of 0.764 ± 0.276 and PPV 0.217 ± 0.207. Its distribution was not significantly different from the mean DSC of inter-radiologist segmentation (p = 0.108, Wilcoxon test). ADC and lesion volume intraclass correlation coefficient (ICC) of the GS and of the correctly identified lesions by the SA was 0.996 for the median and 0.894 for the lesion volume (p < 0.001). The duration of the lesion volume segmentation by the SA was, on average, 10.22 ± 0.86 min, per patient.ConclusionsThe SA provides equally reproducible segmentation results when compared to the manual segmentation of radiologists. Thus, the proposed method offers robust and efficient segmentation of MM lesions on WB-DWI. This method may aid accurate assessment of tumor burden and therefore provide insights to treatment response assessment.

In Vivo Magnetic Resonance Imaging of the Rat Vocal Folds After Systemic Dehydration and Rehydration.

Objective Consuming less water (systemic dehydration) has long been thought to dehydrate the vocal folds. An in vivo, repeated measures study tested the assumption that systemic dehydration causes vocal fold dehydration. Proton density (PD)-weighted magnetic resonance imaging (MRI) of rat vocal folds was employed to investigate (a) whether varying magnitudes of systemic dehydration would dehydrate the vocal folds and (b) whether systemic rehydration would rehydrate the vocal folds. Method Male (n = 25) and female (n = 14) Sprague Dawley rats were imaged with 7T MRI, and normalized PD-weighted signal intensities were obtained at predehydration, following dehydration, and following rehydration. Animals were dehydrated to 1 of 3 levels by water withholding to induce body weight loss: mild (< 6% body weight loss), moderate (6%-10% body weight loss), and marked (> 10% body weight loss). Results There was a significant decrease in vocal fold signal intensities after moderate and marked dehydration (p < .0167). Rehydration increased the normalized signal intensity to predehydration levels for only the moderate group (p < .0167). Normalized signal intensity did not significantly change after mild dehydration or when the mildly dehydrated animals were rehydrated. Additionally, there were no significant differences in PD-weighted MRI normalized signal intensity between male and female rats (p > .05). Conclusion This study provides evidence supporting clinical voice recommendations for rehydration by increasing water intake after an acute, moderate systemic dehydration event. However, acute systemic dehydration of mild levels did not dehydrate the vocal folds as observed by PD-weighted MRI. Future programmatic research will focus on chronic, recurring systemic dehydration.

Non-contact optical coherence tomography - an effective method for visualizing the exudate of the middle ear

Otitis media with effusion (OME) accounts for 15-17% of the total number of recorded diseases of the middle ear. Surgical methods have become much more common. One of the factors affecting the tactics and effectiveness of treatment OME is the degree of viscosity of the effusion. Modern diagnostic methods do not allow to reliably identify cases of OME with high effusion viscosity. To study the possibilities of optical coherence tomography (OCT) in the diagnosis of OME and a non-invasive study of effusion viscosity. An analysis of the results of the examination of 29 patients who underwent surgical treatment for OME - tympanostomy. A control group of 30 patients without middle ear pathology. The study used a spectral OCT with a non-contact probe designed specifically for studies of the structural middle ear. Quantitative analysis of the results using open source ImageJ. Objectification of the degree of viscosity of the effusion was carried out by means of viscometry. A comparative analysis of the intensity of the optical signal in the external auditory canal (EAC) and in the tympanic cavity (TC) was performed, as well as a comparison of the signal from viscous and fluid effusion. In all patients with OME, during the OCT study, an optical signal with a higher intensity was recorded in TC than in the EAC. In all cases, in the control group in the TC, an optical signal was recorded that was identical in intensity with the signal in the EAC. When measuring the degree of viscosity of the effusion, 17 cases of OME were characterized as effusion of a low degree of viscosity, 12 cases - effusion of extreme viscosity. When comparing the average intensity of the optical signal of the OCT images of viscous and liquid effusion, a statistically significant difference was revealed, p<0.001. OCT makes it possible to detect light scattering from large scatterers - cell structures characteristic of low viscosity effusion. In addition, OCT allows you to register an optical signal from small scatterers - high molecular weight structures that are present in large quantities in viscous effusion. A correlation was found between the intensity of the optical signal in the TC and the degree of viscosity of the middle ear effusion. Based on OCT data, it is possible to determine the indications for surgical treatment of OME by detecting viscous exudate.

Bacteria and fungi differentially contribute to carbon and nitrogen cycles during biological soil crust succession in arid ecosystems

Biological soil crusts (BSCs) are widely considered critical for soil fertility in arid ecosystems. However, how microbial communities regulate the C and N cycles during BSC succession is not well understood. We utilized GeoChip 5.0 to analyze the functional potential of bacteria and fungi involved in the C and N cycles of BSCs along a 61-year revegetation chronosequence. The normalized average signal intensities of different functional genes involved in C and N metabolism in 61-year-old BSCs were significantly different from those in younger BSCs and most functional gene subcategories and the corresponding dominant functional populations were derived from bacterial rather than fungal communities. Most C degradation genes (dominated by the starch-degrading gene amyA) were derived from Actinobacteria (mainly Streptomyces) in bacteria, but Ascomycota (mainly Aspergillus) was the key population for lignin degradation (dominated by the phenol oxidase gene) during BSC succession. N cycle genes involved in denitrification (such as narG, nirK/S, and nosZ) and N fixation (nifH) were mainly derived from Unclassified Bacteria, whereas genes involved in ammonification (ureC) were mainly derived from Streptomyces. Moreover, redundancy analysis showed that soil biogeochemical properties were closely related to bacterial and fungal functional gene structures during BSC succession. These findings indicate that bacteria play a crucial role in the regulation of C and N cycles during BSC succession in arid ecosystems, while fungi perform supplementary degradation of lignin, and these communities can successfully stimulate an increase in C and N metabolism in soil during the later successional stages of BSCs.

Delivering the diluted contrast agent with saline via a spiral flow tube improves arterial enhancement for contrast enhancement of magnetic resonance angiography of the neck: A retrospective study.

A contrast agent can be pushed by a saline solution more effectively through a spiral flow tube than through a conventional T-shaped tube in contrast-enhanced magnetic resonance angiography (CEMRA). To compare the degree of contrast enhancement and signal stability in the carotid artery by using CEMRA between a spiral flow tube and a T-shaped tube.A total of 100 patients were analyzed in this retrospective study. The first 50 patients underwent CEMRA of the carotid artery with the T-shaped tube, while the last 50 patients used the spiral flow tube. Gadoterate meglumine was diluted with saline to make a total volume of 20 mL. Injection was performed with a bolus rate of 2.5 mL/s for 8 seconds. Five regions of interest (ROIs) were placed on the contrast-enhanced area in each carotid artery and the signal intensity (SI) in the ROI was used for the analysis. The ROIs on the brain stem were also placed and the average SI in this ROI was used as a reference signal. The enhancement of the artery (E artery) was calculated as a normalized signal using the following equation: E artery = SI in the ROI of the carotid bifurcation/SI in the ROI of the brain stem. Signal homogeneity in the contrast-enhanced area (SHenhance) was assessed by calculating the coefficient of variation from the SI in the 5 ROIs. The value of SHenhance and E artery between the data obtained from the spiral flow tube and the T-shaped tube were compared. P-values <.05 were considered significant.We found a significant difference in SHenhance between the data obtained from the spiral flow tube (0.20 ± 0.060) and the T-shaped tube (0.24 ± 0.056) (P = .001). The E artery values significantly increased by 15% (spiral flow tube, median 14.1 with interquartile range [IQR] 11.8–15.4 vs T-shaped tube, median 12.3 IQR 11.3–14.0, P = .02) using the spiral flow tube.These findings suggest that, by using the Spiral flow tube, the homogeneity of the contrast-enhanced signal intensity in the carotid artery was significantly improved without decreasing the signal intensity in CEMRA.

Whole-Brain Myelin Imaging Using 3D Double-Echo Sliding Inversion Recovery Ultrashort Echo Time (DESIRE UTE) MRI.

Background Signal contamination from long T2 water is a major challenge in direct imaging of myelin with MRI. Nulling of the unwanted long T2 signals can be achieved with an inversion recovery (IR) preparation pulse to null long T2 white matter within the brain. The remaining ultrashort T2 signal from myelin can be detected with an ultrashort echo time (UTE) sequence. Purpose To develop patient-specific whole-brain myelin imaging with a three-dimensional double-echo sliding inversion recovery (DESIRE) UTE sequence. Materials and Methods The DESIRE UTE sequence generates a series of IR images with different inversion times during a single scan. The optimal inversion time for nulling long T2 signal is determined by finding minimal signal on the second echo. Myelin images are generated by subtracting the second echo image from the first UTE image. To validate this method, a prospective study was performed in phantoms, cadaveric brain specimens, healthy volunteers, and patients with multiple sclerosis (MS). A total of 20 healthy volunteers (mean age, 40 years ± 13 [standard deviation], 10 women) and 20 patients with MS (mean age, 58 years ± 8; 15 women) who underwent MRI between November 2017 and February 2019 were prospectively included. Analysis of variance was performed to evaluate the signal difference between MS lesions and normal-appearing white matter in patients with MS. Results High signal intensity and corresponding T2* and T1 of the extracted myelin vesicles provided evidence for direct imaging of ultrashort-T2 myelin protons using the UTE sequence. Gadobenate dimeglumine phantoms with a wide range of T1 values were selectively suppressed with DESIRE UTE. In the ex vivo brain study of MS lesions, signal loss was observed in MS lesions and was conformed with histologic analysis. In the human study, there was a significant reduction in normalized signal intensity in MS lesions compared with that in normal-appearing white matter (0.19 ± 0.10 vs 0.76 ± 0.11, respectively; P < .001). Conclusion The double-echo sliding inversion recovery ultrashort echo time sequence can generate whole-brain myelin images specifically with a clinical 3-T scanner. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Port in this issue.

Rapid Identification of Protein-Protein Interactions in Plants.

Enzyme-enzyme interactions can be discovered by affinity purification mass spectrometry (AP-MS) under in vivo conditions. Tagged enzymes can either be transiently transformed into plant leaves or stably transformed into plant cells prior to AP-MS. The success of AP-MS depends on the levels and stability of the bait protein, the stability of the protein-protein interactions, and the efficiency of trypsin digestion and recovery of tryptic peptides for MS analysis. Unlike in-gel-digestion AP-MS, in which the gel is cut into pieces for several independent trypsin digestions, we uses a proteomics-based in-solution digestion method to directly digest the proteins on the beads following affinity purification. Thus, a single replicate within an AP-MS experiment constitutes a single sample for LC-MS measurement. In subsequent data analysis, normalized signal intensities can be processed to determine fold-change abundance (FC-A) scores by use of the SAINT algorithm embedded within the CRAPome software. Following analysis of co-sublocalization of "bait" and "prey," we suggest considering only the protein pairs for which the intensities were more than 2% compared with the bait, corresponding to FC-A values of at least four within-biological replicates, which we recommend as minimum. If the procedure is faithfully followed, experimental assessment of enzyme-enzyme interactions can be carried out in Arabidopsis within 3 weeks (transient expression) or 5 weeks (stable expression). © 2019 The Authors. Basic Protocol 1: Gene cloning to the destination vectors Alternate Protocol: In-Fusion or Gibson gene cloning protocol Basic Protocol 2: Transformation of baits into the plant cell culture or plant leaf Basic Protocol 3: Affinity purification of protein complexes Basic Protocol 4: On-bead trypsin/LysC digestion and C18 column peptide desalting and concentration Basic Protocol 5: Data analysis and quality control.

NIMG-33. TUMOR GROWTH AND MRI TRAJECTORIES IN GRADE II AND III GLIOMA

Abstract INTRODUCTION The purpose of this work was to investigate the trajectory of tumor growth and multiparametric MRI characteristics in grade II and III gliomas leading up to the onset of new contrast enhancement or the expansion of FLAIR signal abnormality. METHODS Fifty-one grade II and III glioma patients (39 grade II, 12 grade III) underwent serial MR imaging at standard of care timepoints. Multiparametric MR imaging was performed and maps of the apparent diffusion coefficient (ADC) and percentiles (10th, 50th, 90th) from histograms of normalized signal intensities were calculated. Regions of Interest (ROIs) were defined for the entire T2/FLAIR lesion, and when present, the contrast-enhancing (CE) lesion. Serial imaging parameters were acquired for each of these ROIs. Linear rates of change were calculated for CE volume, T2/FLAIR volume, normalized T2 FSE intensity within the FLAIR volume, normalized T2/FLAIR intensity within the FLAIR volume, and normalized median, 10th percentile and 90th% ADC values within the FLAIR volume. RESULTS Thirty-nine patients progressed while on study (7 by CE growth, 32 by T2/FLAIR growth), and 12 patients remained stable, according to RANO criteria. In progressed patients, T2/FLAIR volume and T2 FSE intensity increased over time to progression. The rate of T2/FLAIR volume growth was significantly greater in progressed than stable patients (mean = .42, -.07 mL/week, respectively). The rate of normalized T2/FLAIR signal intensity change was also significantly different in progressed than stable patients (mean = -.002, .0035 mL/week). There were no significant interactions with grade or molecular subgroup by WHO criteria. Additionally, 44% (17/39) of progressed patients by RANO criteria were characterized as having stable disease by radiologic assessment. CONCLUSION Tumor volumes remain the gold standard for response assessment in lower grade gliomas and there exists a need for standardized measurement as visual assessment for determination of tumor status is inconsistent.

Middle Cerebral Artery Plaque Hyperintensity on T2-Weighted Vessel Wall Imaging Is Associated with Ischemic Stroke.

Vessel wall imaging can identify intracranial atherosclerotic plaque and give clues about its components. We aimed to investigate whether the plaque hyperintensity in the middle cerebral artery on T2-weighted vessel wall imaging is associated with ischemic stroke. We retrospectively reviewed our institutional vessel wall MR imaging data base. Patients with an acute ischemic stroke within 7-day onset in the MCA territory were enrolled. Patients with stroke and stenotic MCA plaque (stenosis degree, ≥50%) were included for analysis. Ipsilateral MCA plaque was defined as symptomatic, and contralateral plaque, as asymptomatic. Plaque was manually delineated on T2-weighted vessel wall imaging. The plaque signal was normalized to the ipsilateral muscle signal. The thresholds and volume of normalized plaque signal were investigated using logistic regression and receiver operating characteristic analysis to determine the association between normalized plaque signal and stroke. One hundred eight stenotic MCAs were analyzed (from 88 patients, 66 men; mean age, 58 ± 15 years), including 72 symptomatic and 36 asymptomatic MCA plaques. Symptomatic MCA plaque showed larger plaque hyperintensity volume compared with asymptomatic MCA plaque. The logistic regression model incorporating stenosis degree, remodeling ratio, and normalized plaque signal 1.3-1.4 (OR, 6.25; 95% CI, 1.90-20.57) had a higher area under curve in differentiating symptomatic/asymptomatic MCA plaque, compared with a model with only stenosis degree and remodeling ratio (area under curve, 0.884 versus 0.806; P =.008). The MCA plaque hyperintensity on T2-weighted vessel wall imaging is independently associated with ischemic stroke and adds value to symptomatic MCA plaque classification. Measuring the normalized signal intensity may serve as a practical and integrative approach to the analysis of intracranial atherosclerotic plaque.

An AIEgen‐Peptide Conjugate as a Phototheranostic Agent for Phagosome‐Entrapped Bacteria

AbstractThe detection and elimination of intracellular bacteria remain a major challenge. In this work, we report an aggregation‐induced emission (AIE) bioprobe that can detect bacterial infection and kill bacteria surviving inside macrophages through a dynamic process, notably specific molecular tailoring of the probe by caspase‐1 activation in infected macrophages and accumulation of the residue on phagosomes containing bacteria, leading to light‐up fluorescent signals. Moreover, the AIEgen can serve as a photosensitizer for generation of reactive oxygen species (ROS); and the average ROS indicator fluorescent signal intensity per unit area in the bacterial phagosomes is approximately 2.7‐fold higher than that in the cytoplasm. This, in turn, induces bacteria killing with high efficiency and minimal cytotoxicity towards macrophages. We envision that this specific light‐up bioprobe may provide a new approach for selective and sensitive detection and eradication of intracellular bacterial infections.

An AIEgen-Peptide Conjugate as a Phototheranostic Agent for Phagosome-Entrapped Bacteria.

The detection and elimination of intracellular bacteria remain a major challenge. In this work, we report an aggregation-induced emission (AIE) bioprobe that can detect bacterial infection and kill bacteria surviving inside macrophages through a dynamic process, notably specific molecular tailoring of the probe by caspase-1 activation in infected macrophages and accumulation of the residue on phagosomes containing bacteria, leading to light-up fluorescent signals. Moreover, the AIEgen can serve as a photosensitizer for generation of reactive oxygen species (ROS); and the average ROS indicator fluorescent signal intensity per unit area in the bacterial phagosomes is approximately 2.7-fold higher than that in the cytoplasm. This, in turn, induces bacteria killing with high efficiency and minimal cytotoxicity towards macrophages. We envision that this specific light-up bioprobe may provide a new approach for selective and sensitive detection and eradication of intracellular bacterial infections.

Detection of a High-Turnover Serotonin Circuit in the Mouse Brain Using Mass Spectrometry Imaging.

SummaryMonoamine neurotransmitters are released by specialized neurons regulating behavioral, motor, and cognitive functions. Although the localization of monoaminergic neurons in the brain is well known, the distribution and kinetics of monoamines remain unclear. Here, we generated a murine brain atlas of serotonin (5-HT), dopamine (DA), and norepinephrine (NE) levels using mass spectrometry imaging (MSI). We found several nuclei rich in both 5-HT and a catecholamine (DA or NE) and identified the paraventricular nucleus of the thalamus (PVT), where 5-HT and NE are co-localized. The analysis of 5-HT fluctuations in response to acute tryptophan depletion and infusion of isotope-labeled tryptophan in vivo revealed a close kinetic association between the raphe nuclei, PVT, and amygdala but not the other nuclei. Our findings imply the existence of a highly dynamic 5-HT-mediated raphe to PVT pathway that likely plays a role in the brain monoamine system.

Superior vestibular neuritis: improved detection using FLAIR sequence with delayed enhancement (1 h)

Vestibular neuritis is the second cause of vertigo and new imaging protocols using delayed FLAIR with double-dose of gadolinium are proposed for its diagnosis. Our aim is to demonstrate that a single dose of gadolinium is sufficient. Thirty-three patients with a unilateral vestibular neuritis are compared to a control group. All patients underwent a FLAIR sequence, 1hour after intravenous injection of a single dose of gadolinium, on a 1.5 Tesla MRI. Two radiologists analyzed the enhancement intensity of the superior (sup VN) and inferior vestibular nerve (inf VN) and ratios to the signal of the cerebellum were calculated (supVN/C). The statistics were performed using Bayesian analysis. A strong enhancement of the sup VN was observed on the pathological side in 85% of patients with vestibular neuritis. The average signal intensity of the pathological sup VN (139 units ± 44) was more than two times the average intensity in the control group (58.5 units ± 5). The average ratios supVN/C were significantly different between the pathological side in vestibular neuritis (2.43 units ± 0.63) and the control group [1.16 ± 0.14 (Pr(diff > 0) = 1)]. A delayed enhancement > 71.5 units had a sensitivity of 96% and a specificity of 100% for the diagnosis of superior vestibular neuritis. A delayed FLAIR sequence, acquired 1hour after a single dose of gadolinium injection, is a useful method for the diagnosis of vestibular neuritis. An enhancement of the sup VN > 71.5 units was in favor of the diagnosis.

Rhabdomyolysis and muscle infarcts associated with intra-operative compression

Rhabdomyolysis and muscle infarcts associated with intra-operative compression

Abstract 4569: Intra- and inter-run assessment of reproducibility and quantification of UltiMapper™ I/O APC and T-act kits for tissue multiplexing

Abstract Background: The field of immuno-oncology research has enthusiastically adopted multiplex immunohistochemistry (IHC) techniques to establish the spatial relationships between various immune cell populations in a tumor biology in context. Multiplexing enables researchers to gain a deeper understanding and insight into the tumor microenvironment. Unfortunately, many multiplexing technologies face several challenges, specifically in generating highly robust, reproducible, and easily quantifiable data sets. Ultivue’s UltiMapper I/O APC and T-act kits utilize InSituPlex® technology, a new method of multiplexed IHC that utilizes a streamlined workflow with single antigen retrieval, staining, amplification, and detection steps, allowing for the completion of the assay in 5 hours. Here we assess these kits for intra- and inter-run reproducibility and quantification. Methods: Intra-run reproducibility and quantification was accomplished by manually staining 5 serial sections from three tissue types (deidentified samples of tonsil, melanoma, NSCLC) with one set for each of the UltiMapper I/O APC (CD11c, CD20, CD68/CD163, and MHC Class II) and T-act (CD3, Granzyme B, Ki67, and pan-Cytokeratin/SOX10) kits. Inter-run assessment was determined by staining each slide from a set of five serial sections of each tissue type independently. Images were acquired using the ZEISS® Axio Scan.Z1, without the need for linear unmixing allowing for direct whole slide imaging. Analysis was accomplished using Indica Labs HALO® software. Coefficients of variation (CVs) were calculated based on resulting data. Results: Analysis of intra-run serial section images revealed that cell counts from section to section had CVs of &amp;lt;10% across all markers, in all tissues, for both the UltiMapper I/O APC and T-act kits. This included total cell counts and average signal intensity. Similar results were seen for inter-run comparisons for both kits (&amp;lt;10% CV). Conclusions: The results presented here indicate that InSituPlex technology is potentially much more reproducible than other tissue multiplexing techniques currently available. Histological standards for coefficients of variation in IHC based assays are typically &amp;lt;15%. Data presented here falls well within that standard indicating the potential for future translational applications. In conclusion, InSituPlex is a highly reproducible and quantifiable multiplexing technology that is able to produce these results across a variety of tissue types and markers. Note: This abstract was not presented at the meeting. Citation Format: Bonnie Phillips, Katir Patel, Courtney Hebert, Aditi Sharma, Jamie Buell, Sean Downing. Intra- and inter-run assessment of reproducibility and quantification of UltiMapper™ I/O APC and T-act kits for tissue multiplexing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4569.

Objective and Automated Detection of Diffuse White Matter Abnormality in Preterm Infants Using Deep Convolutional Neural Networks.

Diffuse white matter abnormality (DWMA), or diffuse excessive high signal intensity is observed in 50–80% of very preterm infants at term-equivalent age. It is subjectively defined as higher than normal signal intensity in periventricular and subcortical white matter in comparison to normal unmyelinated white matter on T2-weighted MRI images. Despite the well-documented presence of DWMA, it remains debatable whether DWMA represents pathological tissue injury or a transient developmental phenomenon. Manual tracing of DWMA exhibits poor reliability and reproducibility and unduly increases image processing time. Thus, objective and ideally automatic assessment is critical to accurately elucidate the biologic nature of DWMA. We propose a deep learning approach to automatically identify DWMA regions on T2-weighted MRI images. Specifically, we formulated DWMA detection as an image voxel classification task; that is, the voxels on T2-weighted images are treated as samples and exclusively assigned as DWMA or normal white matter voxel classes. To utilize the spatial information of individual voxels, small image patches centered on the given voxels are retrieved. A deep convolutional neural networks (CNN) model was developed to differentiate DWMA and normal voxels. We tested our deep CNN in multiple validation experiments. First, we examined DWMA detection accuracy of our CNN model using computer simulations. This was followed by in vivo assessments in a cohort of very preterm infants (N = 95) using cross-validation and holdout validation. Finally, we tested our approach on an independent preterm cohort (N = 28) to externally validate our model. Our deep CNN model achieved Dice similarity index values ranging from 0.85 to 0.99 for DWMA detection in the aforementioned validation experiments. Our proposed deep CNN model exhibited significantly better performance than other popular machine learning models. We present an objective and automated approach for accurately identifying DWMA that may facilitate the clinical diagnosis of DWMA in very preterm infants.

Changes in Cross-sectional Area and Signal Intensity of Healing Anterior Cruciate Ligaments and Grafts in the First 2 Years After Surgery

Background: The quality of a repaired anterior cruciate ligament (ACL) or reconstructed graft is typically quantified in clinical studies by evaluating knee, lower extremity, or patient performance. However, magnetic resonance imaging of the healing ACL or graft may provide a more direct measure of tissue quality (ie, signal intensity) and quantity (ie, cross-sectional area). Hypotheses: (1) Average cross-sectional area or signal intensity of a healing ACL after bridge-enhanced ACL repair (BEAR) or a hamstring autograft (ACL reconstruction) will change postoperatively from 3 to 24 months. (2) The average cross-sectional area and signal intensity of the healing ligament or graft will correlate with anatomic features of the knee associated with ACL injury. Study Design: Cohort study; Level of evidence, 2. Methods: Patients with a complete midsubstance ACL tear who were treated with either BEAR (n = 10) or ACL reconstruction (n = 10) underwent magnetic resonance imaging at 3, 6, 12, and 24 months after surgery. Images were analyzed to determine the average cross-sectional area and signal intensity of the ACL or graft at each time point. ACL orientation, stump length, and bony anatomy were also assessed. Results: Mean cross-sectional area of the grafts was 48% to 98% larger than the contralateral intact ACLs at all time points (P < .01). The BEAR ACLs were 23% to 28% greater in cross-sectional area than the contralateral intact ACLs at 3 and 6 months (P < .02) but similar at 12 and 24 months. The BEAR ACLs were similar in sagittal orientation to the contralateral ACLs, while the grafts were 6.5° more vertical (P = .005). For the BEAR ACLs, a bigger notch correlated with a bigger cross-sectional area, while a shorter ACL femoral stump, steeper lateral tibial slope, and shallower medial tibial depth were associated with higher signal intensity (R2 > .40, P < .05). Performance of notchplasty resulted in an increased ACL cross-sectional area after the BEAR procedure (P = .007). No anatomic features were correlated with ACL graft size or signal intensity. Conclusion: Hamstring autografts were larger in cross-sectional area and more vertically oriented than the native ACLs at 24 months after surgery. BEAR ACLs had a cross-sectional area, signal intensity, and sagittal orientation similar to the contralateral ACLs at 24 months. The early signal intensity and cross-sectional area of the repaired ACL may be affected by specific anatomic features, including lateral tibial slope and notch width—observations that deserve further study in a larger cohort of patients. Registration: NCT02292004 (ClinicalTrials.gov identifier)