Mean Signal Intensity Research Articles

Reliability of T2-weighted signal intensity-based quantitative measurements and visual grading of lumbar disc degeneration on MRI.

Decrease in signal intensity (SI) of the nucleus pulposus (NP) on T2-weighted (T2W) images, a sign of disc degeneration (DD), is usually graded based on an observer's image interpretation. No gold standard for quantitative assessment of NP SI exists to date. To compare different quantitative methods and visual gradings of lumbar DD and to evaluate the ability of the quantitative methods to differentiate DD grades. The mean SI of 95 lumbar discs was measured from sagittal T2W images using three regions of interest (ROI): the whole disc, ellipsoid ROI on the NP, and targeted ROI on the most homogenous, brightest area of the NP. SI values were adjusted with cerebrospinal fluid (CSF) SI and compared with vertebral bone SI-adjusted values. DD was evaluated with Pfirrmann grading and visual grading of NP SI. Intra- and inter-observer agreements and relationships between measurements and visual gradings were assessed. Repeatability of all measurements was excellent. All measurements had a strong correlation with Pfirrmann grading and visual NP SI grading, and the CSF SI-adjusted values had a stronger correlation than the vertebral bone SI-adjusted values. The SI values obtained with the targeted ROI had the most significant differences between visual DD grades. Quantitative measurement of the NP SI provides a reliable method for evaluating lumbar DD. Targeted selection of the NP structures included in the measurement offers the best differentiation of DD grades. A reliable quantitative method for DD evaluation is needed for the development of machine-learning-based DD classification.

Vacuoles related to tissue neuron-astrocyte ratio and infiltration of macrophages/monocytes contribute to hyperintense brain signals on diffusion-weighted magnetic resonance imaging in sporadic Creutzfeldt-Jakob disease

BackgroundRadiological features in patients with sporadic Creutzfeldt-Jakob disease (sCJD) are hyperintensity of the cerebral cortex and the basal ganglia displayed by diffusion-weighted magnetic resonance imaging (DW-MRI). We performed a quantitative study on neuropathological and radiological findings. MethodsPatient 1 received a definite diagnosis of MM1-type sCJD, while patient 2 received a definite diagnosis of MM1 + 2-type sCJD. Two DW-MRI scans were performed on each patient. DW-MRI was either taken the day before or on the day of the patient's death, and several hyperintense or isointense areas were marked as a region of interest (ROI). Mean signal intensity of the ROI was measured. Pathological quantitative assessments of the vacuoles, astrocytosis, infiltration of monocytes/macrophages, and proliferation of microglia was performed. Vacuole load (% area vacuole), glial fibrillary acidic protein (GFAP), CD68, and Iba-1 load were calculated. We defined spongiform change index (SCI) to indicate vacuoles related to a tissue neuron-astrocyte ratio. We assessed the correlation of intensity of the last DW-MRI and the pathological findings as well as association of changes of the signal intensity on the sequential images and the pathological findings. ResultWe observed a strong positive correlation between SCI and DW-MRI intensity. In the analysis using serial DW-MRI and pathological findings, we found that CD68 load was significantly larger in areas where signal intensity decreased, as compared to those areas where hyperintensity remained unchanged. ConclusionDW-MRI intensity in sCJD is associated with the ratio of neuron to astrocyte in the vacuoles and the infiltration of macrophages and/or monocytes.

Predicting tumor consistency and extent of resection in non-functioning pituitary tumors.

To (1) identify a radiological parameter to predict non-functioning pituitary tumor (NFPT) consistency, (2) examine the relationship between NFPT consistency and extent of resection (EOR), (3) investigate if tumor consistency predictors can anticipate EOR. The ratio (T2SIR) between the T2 min signal intensity (SI) of the tumor and the T2 mean SI of the CSF was the main radiological parameter, being determined through a radiomic-voxel analysis and calculated using the following formula: T2SIR = [(T2 tumor mean SI - SD)/T2 CSF SI]. The tumor consistency was pathologically estimated as collagen percentage (CP). EOR of NFPTs was evaluated by exploiting a volumetric technique and its relationship with the following explanatory variables was explored: CP, Knosp-grade, tumor volume, inter-carotid distance, sphenoidal sinus morphology, Hardy-grade, suprasellar tumor extension. A statistically significant inverse correlation between T2SIR and CP was demonstrated (p = 0.0001), with high diagnostic power of T2SIR in predicting NFPT consistency (ROC curve analysis' AUC = 0.88; p = 0.0001). The following predictors of EOR were identified in the univariate analysis: CP (p = 0.007), preoperative volume (p = 0.045), Knosp grade (p = 0.0001), tumor suprasellar extension (p = 0.044). The multivariate analysis demonstrated two variables as unique predictors of EOR: CP (p = 0.002) and Knosp grade (p = 0.001). The T2SIR was a significant predictor of EOR both in the univariate (p = 0.01) and multivariate model (p = 0.003). This study offers the potential to improve NFPT preoperative surgical planning and patient counseling by employing the T2SIR as a preoperative predictor of tumor consistency and EOR. Meanwhile, tumor consistency and Knosp grade were found to play an important role in predicting EOR.

Application of Multiparameter Quantitative Magnetic Resonance Imaging in the Evaluation of Graves' Ophthalmopathy.

Assessment of the activity of Graves' ophthalmopathy (GO) is difficult. Existing methods need improvement. Investigate the application of multiparametric magnetic resonance imaging (MRI) in GO. Retrospective. A total of 235 GO patients (age: 38.8± 13.4 years; 90 male; 96 active patients). Short-tau inversion recovery (STIR) fast spin echo, multiecho spin echo T2 mapping and 3D T1-weighted fast field echo sequences at 3.0 T. Two physicians assessed the mean and maximum signal intensity ratio of extraocular muscles to white matter (SIR), T2 relaxation time (T2RT), extraocular muscle area (EMA), fat fraction (FF), retrobulbar fat volume (RFV), and extraocular muscle volume (EMV). Clinical activity score (CAS)≧3 was in active stage. The optimal cut-off point of diagnostic efficacy was selected using receiver operating characteristic (ROC) curve analysis and evaluated using area under the curve (AUC), compared using Student's t test, analysis of variance or Kruskal-Wallis H test. The correlation used Pearson correlation analysis. The discriminant equation used a binary logistic regression analysis. P < 0.05 was considered statistically significant. The SIRmean, SIRmax, T2RTmean, T2RTmax, EMA, and EMV in active GO patients were significantly higher than those in inactive and were positively correlated with CAS (r=0.276, 0.228, 0.438, 0.388, 0.502, and 0333, respectively). The FFmax of active patients was significantly lower than that of inactive patients and was negatively correlated with CAS (r=-0.44). Logistic regression analysis indicated that T2RTmean was independently associated with GO active periods and had good diagnostic performance (area under ROC curve=0.736, sensitivity 70.7%, specificity 69.3%). T2RTmean≧74.295 could be a diagnostic cut-off for judging GO activity (sensitivity 55.3%). SIR, T2RT, EMV, and FF can quantitatively assess the activity and severity of GO and can potentially provide a basis for clinical judgment and selection of treatment options. 4. Stage 2.

Visual and quantitative assessment of hip implant-related metal artifacts at low field MRI: a phantom study comparing a 0.55-T system with 1.5-T and 3-T systems

BackgroundTo investigate hip implant-related metal artifacts on a 0.55-T system compared with 1.5-T and 3-T systems.MethodsTotal hip arthroplasty made of three different alloys were evaluated in a water phantom at 0.55, 1.5, and 3 T using routine protocols. Visually assessment (VA) was performed by three readers using a Likert scale from 0 (no artifacts) to 6 (extremely severe artifacts). Quantitative assessment (QA) was performed using the coefficient of variation (CoV) and the fraction of voxels within a threshold of the mean signal intensity compared to an automatically defined region of interest (FVwT). Agreement was evaluated using intra/inter-class correlation coefficient (ICC).ResultsInterreader agreement of VA was strong-to-moderate (ICC 0.74−0.82). At all field strengths (0.55-T/1.5-T/3-T), artifacts were assigned a lower score for titanium (Ti) alloys (2.44/2.9/2.7) than for stainless steel (Fe-Cr) (4.1/3.9/5.1) and cobalt-chromium (Co-Cr) alloys (4.1/4.1/5.2) (p < 0.001 for both). Artifacts were lower for 0.55-T and 1.5-T than for 3-T systems, for all implants (p ≤ 0.049). A strong VA-to-QA correlation was found (r = 0.81; p < 0.001); CoV was lower for Ti alloys than for Fe-Cr and Co-Cr alloys at all field strengths. The FVwT showed a negative correlation with VA (-0.68 < r < -0.84; p < 0.001).ConclusionsArtifact intensity was lowest for Ti alloys at 0.55 T. For other alloys, it was similar at 0.55 T and 1.5 T, higher at 3 T. Despite an inferior gradient system and a larger bore width, the 0.55-T system showed the same artifact intensity of the 1.5-T system.

Myocardial late gadolinium enhancement using delayed 3D IR-FLASH in the pediatric population: feasibility and diagnostic performance compared to single-shot PSIR-bSSFP

BackgroundThis study compares three-dimensional (3D) high-resolution (HR) late gadolinium enhancement (LGE; 3D HR-LGE) imaging using a respiratory navigated, electrocardiographically-gated inversion recovery gradient echo sequence with conventional LGE imaging using a single-shot phase-sensitive inversion recovery (PSIR) balanced steady-state free precession (bSSFP; PSIR-bSSFP) sequence for routine clinical use in the pediatric population. MethodsPediatric patients (0–18 years) who underwent clinical cardiovascular magnetic resonance (CMR) with both 3D HR-LGE and single-shot PSIR-bSSFP LGE between January 2018 and June 2020 were included. Image quality (0–4) and detection of LGE in the left ventricle (LV) (per 17 segments), in the right ventricle (RV) (per 3 segments), as endocardial fibroelastosis (EFE), at the hinge points, and at the papillary muscles was analyzed by two blinded readers for each sequence. Ratios of the mean signal intensity of LGE to normal myocardium (LGE:Myo) and to LV blood pool (LGE:Blood) were recorded. Data is presented as median (1st–3rd quartiles). Wilcoxon signed rank test and chi-square analyses were used as appropriate. Inter-rater agreement was analyzed using weighted κ-statistics. Results102 patients were included with median age at CMR of 8 (1–13) years-old and 44% of exams performed under general anesthesia. LGE was detected in 55% of cases. 3D HR LGE compared to single-shot PSIR-bSSFP had longer scan time [4:30 (3:35–5:34) vs 1:11 (0:47–1:32) minutes, p < 0.001], higher image quality ratings [3 (3–4) vs 2 (2–3), p < 0.001], higher LGE:Myo [23.7 (16.9–31.2) vs 5.0 (2.9–9.0), p < 0.001], detected more segments of LGE in both the LV [4 (2–8) vs 3 (1–7), p = 0.045] and RV [1 (1–1) vs 1 (0–1), p < 0.001], and also detected more cases of LGE with 13/56 (23%) of patients with LGE only detectable by 3D HR LGE (p < 0.001). 3D HR LGE specifically detected a greater proportion of RV LGE (27/27 vs 17/27, p < 0.001), EFE (11/11 vs 5/11, p = 0.004), and papillary muscle LGE (14/15 vs 4/15, p < 0.001). Inter-rater agreement for the recorded variables ranged from 0.42 to 1.00. Conclusions3D HR LGE achieves greater image quality and detects more LGE than conventional single-shot PSIR-bSSFP LGE imaging, and should be considered an alternative to conventional LGE sequences for routine clinical use in the pediatric population.

Motor-Imagery EEG Signal Classification using Optimized Support Vector Machine by Differential Evolution Algorithm

Background: Motor-Imagery (MI) is a mental or cognitive stimulation without actual sensory input that enables the mind to represent perceptual information. This study aims to use the optimized support vector machine (OSVM) by differential evolution algorithm for motor-Imagery EEG signal classification. Methods: A total of three filters were applied to each signal during the preprocessing phase. The bandstop filter was used to remove urban noise and signal recorders, the median filter to remove random sudden peaks in the signal, and finally, the signal was normalized using the mapminmax filter. The most valuable features were extracted including mean signal intensity, minimum signal value, signal peak value, signal median, signal standard deviation, energy, corticoids, entropy, and signal skewness. Results: The accuracy of the SVM for linear, Gaussian, polynomial, and radial base kernels was 67.3%, 55.1%, 63.6%, and 55.1%, respectively, which was optimized after the classification model by differential evolution algorithm; however, the accuracy for OSVM was increased to 99.6%. Conclusion: Examination of the brain signal appearance for uniform motor-Imagery of both hands showed a significant difference between the signal of motor-Imagery mode with OSVM algorithm (99.6% accuracy), which gave promising results for classification motor imagery EEG signal.

Contrast-Enhanced MRI in Women with Endometrial Cancer: Dynamic Versus Single-Phase Acquisitions.

The 2019 European Society of Urogenital Radiology (ESUR) guidelines for endometrial cancer recommend performing either dynamic contrast-enhanced magnetic resonance imaging (CE MRI) or single-phase CE MRI. However, no study has directly compared these options. Therefore, this study compared dynamic versus single-phase CE MRI for the evaluation of myometrial invasion in women with endometrial cancer. This retrospective, single-institution comparative study was conducted among women with surgically proven endometrial cancer, including 30 consecutive women with single-phase CE MRI and 30 age- and pathologic stage-matched women with dynamic CE MRI. Three readers independently compared dynamic and single-phase CE MRI in terms of the tumor-myometrium signal intensity (SI) difference ratio, depth of myometrial invasion, image quality, and image number. Pathologic findings served as a reference standard for the depth of myometrial invasion. The estimated mean SI difference ratios of dynamic CE MRI and single-phase CE MRI fell within an equivalence margin of 0.05 (90% confidence intervals [CIs] = [-0.0497 to -0.0165], [-0.0226 to -0.0403], and [-0.0429 to -0.0433], respectively, for readers A, B, and C). The area under the receiver operating characteristic curve for the detection of deep myometrial invasion was not significantly different between the acquisitions (P = .3315, P = .3345, and P = .8593, respectively). Single-phase CE MRI showed significantly better image quality than dynamic CE MRI (P = .0143, P = .0042, and P = .0066, respectively), while the median number of images for dynamic CE MRI was 2.4 times higher than that for single-phase CE MRI. Single-phase acquisition may be a better option for CE MRI in women with endometrial cancer than dynamic acquisition.

Effective detection of proteins following electrophoresis using extracts of locally available food species

Procedures in life sciences research laboratories often require chemicals and plasticware that are costly, toxic or pose a risk to the environment. Therefore, sustainable alternatives would be of interest, provided that they generate suitable data quality. Coomassie blue and silver staining are the most widely used methods for detecting proteins following electrophoresis in the laboratory. However, their use presents challenges in terms of safety and waste management. In the current study, aqueous extracts were prepared from a series of common food species and evaluated as alternative stains for protein detection. Beets, blueberries, purple cabbage, raspberries and strawberries were employed to stain identical proteins separated under the same conditions in electrophoresis gels. Extracts of the first two species resulted in protein bands that were detectable through visible light transillumination, whereas extracts from all five species generated specific protein bands under ultraviolet light. The raspberry-derived extract was selected for further study based on the brightness of the fluorescent protein bands and minimal background staining. For both bovine serum albumin and lysozyme at 2.5 μg and 0.5 μg protein per band, the mean signal intensities obtained with raspberry extract staining were just below half of those obtained with Coomassie blue. Furthermore, the mean intensities using raspberry extract were equivalent to those obtained using Coomassie blue in the detection of 0.1 μg protein. Therefore, raspberry could be used to produce an effective stain for the routine laboratory analysis of proteins.

A Pilot Study of Intralesional Injection of Triamcinolone Acetonide for Desmoid Tumors: Two-Year Outcomes.

The purpose of this pilot study was to examine the clinical efficacy and safety of serial triamcinolone injections for the treatment of desmoid tumors. Nine patients were enrolled into this prospective study and underwent three serial ultrasound-guided triamcinolone injections (120 mg) at 6-week intervals. MRI was compared at baseline and every 6 months, out to 24 months. Safety and tolerability were assessed by clinical evaluation and questionnaires, including the 12-item short form survey (SF-12), visual analog scale (VAS), and desmoid patient-reported outcome (PRO) tool. At 24 months, 8 (88.9%) patients demonstrated a reduction in the volume of their tumor while 1 (11.1%) enlarged. Median tumor volume change was -26.9% (-81.1% to 34.6%; P = 0.055) All 9 tumors remained stable based on World Health Organization criteria, whereas 2 (22.2%) demonstrated partial response based on RECIST. There was a significant decrease in the tumor:muscle postcontrast mean signal intensity ratio at 6 months (P = 0.008) and 24 months (P = 0.004). There was a similar decrease in the tumor:muscle T2 mean signal intensity ratio at 24 months (P = 0.02). We found no difference in the SF-12 and VAS scores, but there were significant improvements in the desmoid PRO. Treatment of desmoid tumors with serial triamcinolone injections appears safe and well tolerated by patients, with a 22% partial response based on RECIST. Further research is needed to confirm our results and determine factors predictive of response.

Synthetic double inversion recovery imaging in brain MRI: quantitative evaluation and feasibility of synthetic MRI and a comparison with conventional double inversion recovery and fluid-attenuated inversion recovery sequences

Background and purposeSynthetic MR imaging (SyMRI) allows the reconstruction of various contrast images, including double inversion recovery (DIR), from a single scan. This study aimed to investigate the advantages of SyMRI by comparing synthetic DIR images with synthetic T2-weighted fluid-attenuated inversion recovery (T2W-FLAIR) and conventional DIR images.Materials and methodsWe retrospectively reviewed the imaging data of 100 consecutive patients who underwent brain MRI between December 2018 and March 2019. Synthetic DIR, T2W-FLAIR, T1-weighted, and phase-sensitive inversion recovery (PSIR) images were generated from SyMRI data. For synthetic DIR, the two inversion times required to suppress white matter and cerebrospinal fluid (CSF) were manually determined by two radiologists. Quantitative analysis was performed by manually tracing the region of interest (ROI) at the sites of the lesion, white matter, and CSF. Synthetic DIR, synthetic T2W-FLAIR, and conventional DIR images were compared on the basis of using the gray matter-to-white matter, lesion-to-white matter, and lesion-to-CSF contrast-to-noise ratios.ResultsThe two radiologists showed no differences in setting inversion time (TI) values, and their evaluations showed excellent interobserver agreement. The mean signal intensities obtained with synthetic DIR were significantly higher than those obtained with synthetic T2W-FLAIR and conventional DIR.ConclusionSynthetic DIR images showed a higher contrast than synthetic T2WFLAIR and conventional DIR images.

Larger bone marrow lesion volume before medial open-wedge high tibial osteotomy correlates with better improvement of clinical scores in patients with knee osteoarthritis.

This study evaluated the clinical outcomes of medial open-wedge high tibial osteotomy (MOWHTO) and bone marrow lesion (BML) scores and volumes. The hypotheses were that quantitative BML volume is more associated with clinical outcomes of MOWHTO than qualitative BML evaluations, and pre-operative BML volume is associated with the improvement of clinical outcomes. Patients who underwent MOWHTO were retrospectively enrolled. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was recorded before the initial surgery and at plate removal surgery. Using pre-operative short-time inversion recovery magnetic resonance imaging, BMLs were evaluated using three qualitative scores, reflecting the maximum length, proportion, and intensity of BML. For quantification, BMLs of the femur and tibia were separately defined as lesions with a threshold greater than the mean signal intensity plus two standard deviations, using the corresponding lateral condyles as controls. The association between the KOOS scales and BML scores/volume was evaluated using Spearman's correlation coefficient. Multivariate linear regression analyses for post-operative KOOS scales were performed using the tibial BML volume as one of the four independent variables. The final analysis included 40 MOWHTO cases. Two qualitative BML scores correlated only with pre-operative KOOS sports. Femoral and tibial BML volumes were correlated with post-operative KOOS QOL (ρ = 0.40, p = 0.01) and sports (ρ = 0.36, p = 0.02), respectively. Tibial BML volume was significantly correlated with all five delta KOOS scales (ρ = 0.39-0.51, p = 0.01-0.001), however, femoral BML volume was only correlated with delta KOOS QOL (ρ = 0.41, p = 0.01). In multivariate analyses, tibial BML volume was a significant positive predictor for every post-operative KOOS scale, while post-operative % mechanical axis was also a positive significant variable, except post-operative KOOS pain. Tibial BML volume was positively correlated with one post-operative KOOS scale and all delta KOOS scales. A larger pre-operative tibial BML and appropriate alignment correction were associated with a better post-operative KOOS scales. Pre-operative large BML had no negative influence on post-operative clinical outcomes; hence, surgeons need not hesitate to perform MOWHTO in patients with large BMLs in the medial condyles. Retrospective case series, Level IV.

Imaging finding and analysis of brain lymphoma in contrast-enhanced fluid attenuated inversion recovery sequence

ObjectiveThe purpose of this retrospective study was to report and analyze the image findings of contrast-enhanced fluid-attenuated inversion recovery (CE-FLAIR) sequence of lymphoma in the brain. Material and MethodsThirty-two immunocompetent patients with biopsy-proven diffuse large B-cell type lymphoma in the brain were evaluated with pre-treatment MRI examinations from August 2014 to April 2020. As stereotactic studies on the day of biopsy, FLAIR and T1-weighted axial images were acquired in 2 mm thickness, before and after administrating gadolinium-based contrast agents, with 3.0 Tesla MR machines. Respective subtraction images were also obtained for both CE-FLAIR and contrast-enhanced T1-wieghted image (CE-T1WI) sequences. The imaging findings, especially the enhancement pattern on CE-FLAIR sequence, were analyzed qualitatively and quantitatively, using semi-automatic segmentation. ResultsOn CE-FLAIR images, brain lymphomas were poorly enhanced, while showing peripheral rim enhancement (54 of 58 lesions, 93.1 %) and central enhancing foci (40 of 58 lesions, 69.0 %). Seventy percent of central enhancing foci were correlated to areas with low signal intensity on CE-T1WI. In quantitative analysis, the mean signal intensity of CE-T1WI subtraction was 490.44 and that of FLAIR subtraction was 206.13. The standard deviation of all signal intensity values in CE-T1WI subtraction sequence was 143.45, while that of CE-FLAIR subtraction sequence was 118.41. ConclusionOn CE-FLAIR, brain lymphomas showed relatively poor and homogeneous enhancement, when compared to CE-T1WI. Most brain lymphomas displayed peripheral rim enhancement and central enhancing foci.

Morphologic evaluation of injured and contralateral uninjured ankles in patients with unilateral chronic ankle instability.

To compare the morphological anatomy and abnormalities of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) in unilateral chronic ankle instability (CAI). 22 patients (men: women, 13:9; mean age, 28.95 ± 8.127 years) with unilateral CAI and 18 healthy volunteers (men: women, 9:9, mean age, 28.33 ± 3.678 years) were recruited. MRI scans were divided into Group 1 (22 injured ankles), Group 2 (22 contralateral uninjured ankles), and Group 3 (36 healthy volunteer ankles). The morphologic variables, MRI signal intensity (SI) values were evaluated. The ATFL proximal, intermediate, and distal sites and the CFL proximal and distal sites in Group 3 were narrower than those in Group 1 (P ＜0.05). Both ATFL and CFL in Group 1 were thicker than those in Group 3 (P ＜0.01). The proximal and intermediate sites of the ATFL and the proximal site of the CFL in Group 3 were narrower than those in Group 2 (P ＜0.01). The intermediate site of the ATFL and the proximal and distal sites of the CFL in Group 2 were thicker than those in Group 3 (P ＜0.01). The mean SI values of the ATFL in Group 1 were higher than those in Groups 2 and 3 (P ＜0.01). The ATFL and CFL SI values were higher in Group 2 than those in Group 3 (P ＜0.05). Both the injured and contralateral uninjured ankles had wider ATFL and CFL, more thickness, and higher SI values compared with those of healthy volunteer ankles. High-resolution three-dimensional MRI provides a potential tool assisting clinical decision on the treatment and rehabilitation therapy of patients with unilateral CAI.

Deglycosylation of pathological specimens alters performance of diagnostic PDL1 antibodies.

Immunohistochemical (IHC) predictive quantitation of PDL1 expression is obligatory in many cancer entities with improved response to immune checkpoint inhibition in PDL1-positive subgroups. With recent demonstration of increased positivity rates after enzymatic deglycosylation in breast cancer specimens, a comparative analysis with two different antibodies and extended controls was performed in a cohort of head and neck squamous cell cancer samples (HNSCC).Formalin-fixed paraffin-embedded tissue from HNSCC specimens was used for initial on-slide method optimization based on the PNGase F assay. SDS-PAGE and immunoblotting with the PDL1 antibody 28-8 was performed to evaluate deglycosylation efficiency. A tissue micro array of n = 527 tissue cores of 181 patients with HNSCC was used to determine the effects of deglycosylation on staining pattern and intensity with PDL1 antibodies 28-8 and E1L3N.Successful on-slide deglycosylation with PNGase F was confirmed by immunoblot but varied across replicates. Using E1L3N (intracellular binding domain, most probably not glycosylated), mean signal intensity as well as the fraction of PDL1 positive cells was increased by deglycosylation. Opposite effects were observed with 28-8 (extracellular binding domain, glycosylated).Deglycosylation reduces diagnostic performance of the PDL1 antibody 28-8. In contrast, effects for E1L3N are complex and probably involve reduction of off-target binding leading to specifically improved signal intensity. However, enzymatic deglycosylation adds further variance to IHC.

High frequency of anti-DSG 2 antibodies in post COVID-19 serum samples

BackgroundThere is growing recognition that COVID-19 does cause cardiac sequelae. The underlying mechanisms involved are still poorly understood to date. Viral infections, including COVID-19, have been hypothesized to contribute to autoimmunity, by exposing previously hidden cryptic epitopes on damaged cells to an activated immune system. Given the high incidence of cardiac involvement seen in COVID-19, our aim was to determine the frequency of anti-DSG2 antibodies in a population of post COVID-19 patients. Methods and results300 convalescent serum samples were obtained from a group of post COVID-19 infected patients from October 2020 to February 2021. 154 samples were drawn 6 months post-COVID-19 infection and 146 samples were drawn 9 months post COVID infection. 17 samples were obtained from the same patient at the 6- and 9- month mark. An electrochemiluminescent-based immunoassay utilizing the extracellular domain of DSG2 for antibody capture was used. The mean signal intensity of anti-DSG2 antibodies in the post COVID-19 samples was significantly higher than that of a healthy control population (19 ± 83.2 in the post-COVID-19 sample vs. 2.1 ± 7.2 (p < 0. 0001) in the negative control healthy population). Of note, 29.3% of the post COVID-19 infection samples demonstrated a signal higher than the 90th percentile of the control population and 8.7% were higher than the median found in ARVC patients. The signal intensity between the 6-month and 9-month samples did not differ significantly. ConclusionsWe report for the first time that recovered COVID-19 patients demonstrate significantly higher and sustained levels of anti-DSG2 autoantibodies as compared to a healthy control population, comparable to that of a diagnosed ARVC group.

Neuroimaging Correlates of Substantia Nigra Hyperechogenicity in Parkinson's Disease.

Degeneration of dopaminergic neurons within the brainstem substantia nigra (SN) is both a pathological hallmark of Parkinson's disease (PD) and a major contributor to symptom expression. Therefore, non-invasive evaluation of the SN is critical for diagnosis and evaluation of disease progression. Hyperechogenicity (HE+) on midbrain transcranial sonography (TCS) supports the clinically established diagnosis of PD. Further, postmortem studies suggest involvement of neuromelanin (NM) loss and iron deposition in nigral neurodegeneration and HE+ emergence. However, the associations between HE+ and signs of nigral NM loss and iron deposition revealed by magnetic resonance imaging (MRI) have not been examined. To elucidate the magnetic resonance- (MR-) morphological representation of the HE+ by NM-weighted (NMI) and susceptibility-weighted MRI (SWI). Thirty-four PD patients and 29 healthy controls (HCs) received TCS followed by NMI and SWI. From MR images, two independent raters manually identified the SN, placed seeds in non-SN midbrain areas, and performed semi-automated SN segmentation with different thresholds based on seed mean values and standard deviations. Masks of the SN were then used to extract mean area, mean signal intensity, maximal signal area, maximum signal (for NMI), and minimum signal (for SWI). There were no significant differences in NMI- and SWI-based parameters between patients and HCs, and no significant associations between HE+ extent and NMI- or SWI-based parameters. HE+ on TCS appears unrelated to PD pathology revealed by NMI and SWI. Thus, TCS and MRI parameters should be considered complementary, and the pathophysiological correlates of the HE+ require further study.

Abstract 473: Cilostazol Decreases Venous Outflow Inflammation And Improves Avf Patency Inmurine Arteriovenous Fistula

Background: Arteriovenous fistula (AVF) have high failure rates, and no pharmacotherapeutics can improve AVF patency. The most common cause of AVF failure is inflammation-driven neointimal hyperplasia and thrombosis. Limited observational data suggests that cilostazol (CIL), an FDA-approved phosphodiesterase-3 inhibitor that inhibits platelet activation and smooth muscle cell proliferation, could help improve AVF maturation. Here, we investigated the effects of cilostazol on murine AVF patency, and further assessed the fibrinogenesis and anti-inflammatory effects using intravital fluorescence molecular imaging. Methods: One week prior to fistula creation, mice were randomized to CIL (40mg/kg/day) or PBS group (n=20 each). AVF was created using an end-to-side external jugular vein and carotid artery anastomosis. AVF blood flow was measured post-operatively (Transonic) and then every 7 days until AVF was occluded (&lt;0.1 ml/min). Macrophages and fibrin were imaged after 10mg/kg FMX-AF555 and/or 4.5nmol FTP11CyAm7 i.v. injection prior to imaging on day 7 or day 14, respectively. The target-to-background ratio (TBR) was calculated as mean signal intensity (MSI) of the fistula divided by the MSI of the contralateral vein. Results: Post-operative AVF blood flow was similar between CIL and PBS treated groups (p=0.3). Average AVF patency was significantly longer in CIL group compared to PBS group (42 vs 21 days, p&lt;0.01, figure 1A). Both day 7 and day 14 venous outflow fibrinogenesis signal assessed by IVM was significantly lower in CIL group compared to PBS group (ps&lt;0.05, Figure 1B). On day 14, CIL significantly lower venous outflow FMX signals compared to PBS group (p&lt;0.05). Conclusion: Oral cilostazol therapy prolongs AVF patency, and decreases venous outflow inflammation and fibrinogenesis in experimental AVF in vivo. The current data supports investigating cilostazol as a clinical pro-AVF patency pharmacotherapeutic strategy in dialysis patients.

Quantification of tumor response of cystic vestibular schwannoma to Gamma Knife radiosurgery by using artificial intelligence.

Gamma Knife radiosurgery (GKRS) is a common treatment modality for vestibular schwannoma (VS). The ability to predict treatment response is important in patient counseling and decision-making. The authors developed an algorithm that can automatically segment and differentiate cystic and solid tumor components of VS. They also investigated associations between the quantified radiological features of each component and tumor response after GKRS. This is a retrospective study comprising 323 patients with VS treated with GKRS. After preprocessing and generation of pretreatment T2-weighted (T2W)/T1-weighted with contrast (T1WC) images, the authors segmented VSs into cystic and solid components by using fuzzy C-means clustering. Quantitative radiological features of the entire tumor and its cystic and solid components were extracted. Linear regression models were implemented to correlate clinical variables and radiological features with the specific growth rate (SGR) of VS after GKRS. A multivariable linear regression model of radiological features of the entire tumor demonstrated that a higher tumor mean signal intensity (SI) on T2W/T1WC images (p < 0.001) was associated with a lower SGR after GKRS. Similarly, a multivariable linear regression model using radiological features of cystic and solid tumor components demonstrated that a higher solid component mean SI (p = 0.039) and a higher cystic component mean SI (p = 0.004) on T2W/T1WC images were associated with a lower SGR after GKRS. A larger cystic component proportion (p = 0.085) was associated with a trend toward a lower SGR after GKRS. Radiological features of VSs on pretreatment MRI that were quantified using fuzzy C-means were associated with tumor response after GKRS. Tumors with a higher tumor mean SI, a higher solid component mean SI, and a higher cystic component mean SI on T2W/T1WC images were more likely to regress in volume after GKRS. Those with a larger cystic component proportion also trended toward regression after GKRS. Further refinement of the algorithm may allow direct prediction of tumor response.

Is it Possible to Assess the Functional Status of Hormone Secretion or Non- Secretion of Adrenal Masses Through Their Magnetic Resonance Imaging (MRI) Characteristics?

Diagnostic imaging techniques, including magnetic resonance imaging (MRI) should be performed on all patients with incidentalomas. However, limited number of studies on whether the quantitative measurements (signal intensity index, adrenal to spleen ratio) in MRI could predict the functional status of adrenal adenomas are available. Between 2015-2020, 404 patients (265 females, 139 males) with adrenal mass who were referred to the university hospital for further investigation were included. After detailed diagnostic hormonal evaluation, all patients were examined with the MRI 1.5 T device (Signa, GE Medical Systems; Milwaukee, USA). The signal intensities of the adrenal lesions on T2W images were qualitatively evaluated and noted as homogenous or heterogeneous in comparison with the liver signal intensity (SI). A chemical-shift SI index and chemical shift adrenal-to-spleen SI ratio were also calculated. While 331(81.9%) of the patients had nonfunctional adrenal mass, the rest (n=73, 18.1%) were patients with functional (autonomous cortisol secretion-ACS, Cushing syndrome-CS, pheochromocytoma, primary hyperaldosteronism-PA) adrenal masses. In phase vs. phase values of patients with NFAI, Pheo(n=17), ACS (n=30), CS (n=11), and PA (n=15) were 474.04±126.7 vs. 226.6±132.4, 495.3±182.8 vs. 282.17±189.1, 445.2±134.8 vs. 203.3±76.2, 506.8±126.5 vs. 212.2±73.6 and 496.2±147.5 vs. 246.6±102.1, respectively. Mean signal intensity index (SII) and adrenal to spleen ratio (ASR) of all groups (NFAI, Pheo, ACS, CS, PA) were 52.0±24.8 and 0.51, 44.9±22.5 and 0.55, 49.5±24.5 and 0.53, 56.2±16.4 and 0.43, 47.6±25.1 and 0.54, respectively. Based on the currently accepted measurements in the case of ASR and SII, all lesions were similar and observed as fat rich adenomas (p*= 0.552, p** = 0.45). The quantitative assessment (SII, ASR) of intracellular lipids in an incidentally discovered adrenal tumor could only help distinguish adrenal masses in the case of adenomas or non-adenomas. As an initial diagnostic evaluation, clinical and laboratory assessment to distinguish hormone secretion should be done for all patients with adrenal incidentalomas.