Resolution Recovery Research Articles

Cardiac atrial metabolism quantitative assessment with analog and digital time of flight-PET/computed tomography.

Evaluation of left atrium (LA) remodeling is becoming increasingly relevant in understanding several pathological cardiac conditions. 18 F-FDG-PET/computed tomography (CT), the current gold standard for metabolic evaluation of the left ventricle, could be extended to LA using the latest PET technologies. We sought to perform a phantom study to optimize the reconstruction algorithm in this context. The liver, heart cavity and walls of an anthropomorphic phantom were filled with typical patient 18 F-FDG activity concentrations. Acquisitions were performed on an analog and on a digital TOF-PET/CT, and reconstructed with and without resolution recovery (RR). The Richardson-Lucy RR method was used, either through a third-party software or through the PET/CT manufacturer algorithm. Activity recoveries in the atria and ventricles and signal-to-noise ratios were evaluated to identify the best reconstruction and RR parameters. The same methodology was applied on a patient cardiac study. Analog PET/CT with the third-party RR cannot improve the activity recovery without markedly degrading the image quality. For the digital PET/CT, the optimal algorithm was the manufacturer RR reconstruction using four iterations and 15 subsets combined with five RR iterations. This reconstruction improved the LA activity recovery from 58% to 70% while preserving images of diagnostic quality. Similar results were obtained for the patient study. The digital TOF-PET/CT with the identified optimal reconstruction can be used to quantitatively analyze the LA uptake in 18 F-FDG cardiac studies while still preserving image reading quality. This may lead to more precise cardiovascular disease status evaluation, especially when atria are concerned.

Feasibility of dose reduction for [18F]FDG-PET/MR imaging ofpatients with non-lesional epilepsy.

The aim of the study was to evaluate the effect of reduced injected [18F]FDG activity levels on the quantitative and diagnostic accuracy of PET images of patients with non-lesional epilepsy (NLE).Nine healthy volunteers and nine patients with NLE underwent 60-min dynamic list-mode (LM) scans on a fully-integrated PET/MRI system. Injected FDG activity levels were reduced virtually by randomly removing counts from the last 10-min of the LM data, so as to simulate the following activity levels: 50 %, 35 %, 20 %, and 10 % of the original activity. Four image reconstructions were evaluated: standard OSEM, OSEM with resolution recovery (PSF), the A-MAP, and the Asymmetrical Bowsher (AsymBowsher) algorithms. For the A-MAP algorithms, two weights were selected (low and high). Image contrast and noise levels were evaluated for all subjects while the lesion-to-background ratio (L/B) was only evaluated for patients. Patient images were scored by a Nuclear Medicine physician on a 5-point scale to assess clinical impression associated with the various reconstruction algorithms.The image contrast and L/B ratio characterizing all four reconstruction algorithms were similar, except for reconstructions based on only 10 % of total counts. Based on clinical impression, images with diagnostic quality can be achieved with as low as 35 % of the standard injected activity. The selection of algorithms utilizing an anatomical prior did not provide a significant advantage for clinical readings, despite a small improvement in L/B (< 5 %) using the A-MAP and AsymBowsher reconstruction algorithms.In patients with NLE who are undergoing [18F]FDG-PET/MR imaging, the injected [18F]FDG activity can be reduced to 35 % of the original dose levels without compromising.

LaMiNa: A Creative Synergistic Approach to Facial Rejuvenation.

Treating facial aging with CO2 lasering or microneedling are cornerstones of facial rejuvenation. Skin rejuvenation utilizing thermal and mechanical treatments have historically been considered too injurious to be combined at a single setting. Autologous nanofat has been shown to deliver wound healing properties. We investigated the safety and efficacy of co-terminus CO2 lasering and microneedling to resolve fine lines and rhytids in facial skin with addition of autologous nanofat to aid in recovery. Combination treatments may result in better results with faster recovery. We investigated the safety and efficacy of co-terminus CO2 lasering and microneedling to resolve fine lines and rhytids in facial skin with addition of autologous nanofat to aid in recovery. Twenty-three patients underwent facial treatment with CO2 lasering followed by microneedling and application of autologous nanofat (LaMiNa). One volunteer patient had tissue biopsies of treatment areas to demonstrate histologic tissue level changes. All patients verbally reported no pain (Numerical Rating System 0-10) following procedure and had rapid recovery within an average of 5 days. Pathology results demonstrated that CO2 and microneedling had persistent epidermal disruption and perineural inflammation at 4 days, while the introduction of autologous nanofat at the time of CO2 and microneedling resulted in full recovery of epidermis and resolution of perineural inflammation. Triple therapy (LaMiNa) with thermal CO2 remodeling and mechanical microneedling penetration have accelerated and pain-free recovery with the addition of autologous nanofat. Histologic analysis reveals that epidermal recovery is accelerated and perineural inflammation is reduced with the addition of autologous nanofat following skin remodeling from combined CO2 and microneedling.

Immediate Intraoperative Microsurgical Repair of the Recurrent Laryngeal Nerve: A Fifteen-Year Institutional Experience

Abstract Background Recurrent laryngeal nerve (RLN) injury carries significant morbidity. Microsurgical repair of the RLN has proven promising for enhancing patient recovery of vocal function; however, data remains limited. Methods This retrospective cohort study included patients who underwent RLN repair from 2007 to 2022. Demographics and medical history were collected. The location and etiology of RLN injury, as well as the repair technique, were collected. Follow-up data were collected at the initial postoperative visit, at 6 months and at 1 year. Hoarseness was classified as mild, moderate, or severe. Of patients who underwent nasopharyngolaryngoscopy (NPL) following repair, the glottic gap was measured. Vocal interventions performed were also recorded. This study utilized descriptive statistical methods. Results Eleven patients underwent RLN repair. All patients underwent immediate repair. Fifty-four percent (n = 6) of RLN injuries resulted from tumor inflammation or nerve encasement. Eighty-two percent (n = 9) underwent direct RLN coaptation, 9% (n = 1) underwent vagus-RLN anastomosis, and 9% (n = 1) underwent an interposition nerve graft. Technical success was 100%. Seventy-three percent (n = 8) required otolaryngology referral, and of those, 50% (n = 4) required intervention. At initial evaluation, 91% (n = 10) suffered from mild to severe hoarseness, and of patients who underwent NPL, all had a glottic gap. At 1 year, 82% of patients (n = 9) improved to having mild to no appreciable hoarseness. Of the patients who underwent NPL, 62% (n = 5) had closure of the glottic gap. Conclusion Patients undergoing repair of the RLN following injury showed excellent recovery of vocal function and resolution of glottic gap at 1 year.

228 PD-1-TARGETED T-CELL CHECKPOINT INHIBITORS-RELATED MYOCARDITIS COMPLICATED BY COMPLETE ATRIOVENTRICULAR BLOCK: A CASE SERIES OF SUCCESSFUL MANAGEMENT

Abstract Background Immune checkpoint inhibitors (ICI) have revolutionized the clinical management of a broad spectrum of solid and hematopoietic malignancies over the past decade. ICI are associated with several Immune-related Adverse Events, among which myocarditis and atrioventricular blocks are uncommon but potentially fatal toxicities. Material and Methods We describe two patients undergoing treatment with PD-1 checkpoint inhibitors for metastatic cancers who developed myositis and myocarditis complicated by complete atrioventricular block (CAVB). The first patient had a history of metastatic sarcomatoid urothelial carcinoma treated with Pembrolizumab. After two cycles, he developed eyelid ptosis and was hospitalized for syncopal episodes due to CAVB associated with ICI myocarditis. The second patient had a history of metastatic melanoma and was hospitalized for myocarditis and myositis after the second infusion of Nivolumab. Results In the first case, high-dose corticosteroid therapy was promptly initiated, with subsequent rapid recovery of sinus rhythm and rapid resolution of symptoms. The second patient, despite high-dose corticosteroid therapy, developed CAVB requiring implantation of a definitive PM. After initiation of mycophenolate mofetil and intravenous immunoglobulin therapy, gradual recovery was observed. Both patients had normal left ventricular function with no wall motion abnormalities. However, speckle tracking echocardiography revealed a normal global longitudinal left ventricular strain (GLS) of -19.8% in patient 1 and a depressed GLS of -14.7% in patient 2, consistent with the different evolution of the two myocarditis. Conclusions We recommend a high degree of caution and awareness to all physicians when treating immunotherapy patients. Myocarditis is a relatively rare but potentially fatal event due to its early onset, non-specific clinical presentation and fulminant progression. GLS may be useful in detecting myocardial damage in these patients. Discontinuation of ICI, cardiac pacing, treatment with high-dose corticosteroids and immunosuppressive agents may improve the outcome.

Edge effect removal in Fourier ptychographic microscopy via periodic plus smooth image decomposition

Fourier ptychographic microscopy (FPM) is a promising computational imaging technique with high resolution, wide field-of-view (FOV) and quantitative phase recovery. So far, a series of system errors that may corrupt the image quality of FPM has been reported. However, an imperceptible artifact caused by edge effect caught our attention and may also degrade the precision of phase imaging in FPM with a cross-shape artifact in the Fourier space. We found that the precision of reconstructed phase at the same subregion depends on the different sizes of block processing as a result of different edge conditions, which limits the quantitative phase measurements via FPM. And this artifact is caused by the aperiodic image extension of fast Fourier transform (FFT). Herein, to remove the edge effect and improve the accuracy, two classes of opposite algorithms termed discrete cosine transform (DCT) and periodic plus smooth image decomposition (PPSID) were reported respectively and discussed systematically. Although both approaches can remove the artifacts in FPM and may be extended to other Fourier analysis techniques, PPSID-FPM has a comparable efficiency to conventional FPM algorithm. The PPSID-FPM algorithm improves the standard deviation of phase accuracy as a factor of 4 from 0.08 radians to 0.02 radians. Finally, we summarized and discussed all the reported system errors of FPM within a generalized model.

Multi-Aircraft Flight Conflict Resolution and Trajectory Recovery Scheme Based on Mixed Integer Linear Programming and Geometric Rules

A conflict resolution and trajectory recovery scheme based on heading angle change (HAC) is proposed to solve mid-term conflict between multi-aircraft cruising in a shared airspace. Flight conflict resolution has always been regarded as one of the most important responsibilities of air traffic controllers (ATCOs). The proposed conflict resolution scheme can be applied to decision support tools to assist ATCOs in making decisions. The goals of reducing the possibility of human error and increasing the efficiency of airspace operations can be achieved. Firstly, the flight conflict problem is modeled as a class of optimal control problem. Secondly, the optimal solution can be obtained by mixed integer linear programming (MILP) method based on HAC strategy. Thirdly, a trajectory recovery method based on geometric rules is proposed. It can be found through simulated experiment that the extra flight distance and delay adopting the designed scheme is smaller than the compared method.

Investigating the Feasibility of Using DenseNet to Improve Coronary Calcification Detection in CT

Interscan reproducibility of coronary artery calcium (CAC) scoring can be improved by using a smaller slice thickness but at the cost of higher image noise. This study aimed to investigate the feasibility of using densely connected convolutional network (DenseNet) to reduce the image noise in CAC scans reconstructed with slice thickness < 3 mm for improving coronary calcification detection in CT. Phantom data acquired with QRM and CIRS phantoms were used for model training and testing, where the DenseNet model adopted in this work was a convolutional neural network (CNN) designed for super resolution recovery. After phantom study, the proposed method was evaluated in terms of its ability to improve calcification detection using patient data. The CNN input images (IMGinput) were CAC scans reconstructed with 0.5-, 1.0- and 1.5-mm slice thickness, while CNN label images were CAC scans reconstructed with 3-mm slice thickness (IMG3mm). Region of interest (ROI) analysis was carried out on IMG3mm, IMGinput and CNN output images (IMGoutput). Two-sample t test was used to compare the difference in Hounsfield Unit (HU) values within ROI between IMG3mm and IMGoutput. For the calcifications in QRM phantoms, no statistically significant difference was found when comparing the HU values of 400- and 800-HA calcifications identified on IMG3mm to those on IMGoutput with slice thickness of 0.5, 1.0 or 1.5 mm. On the other hand, statistically significant difference was found when comparing the HU values of 200-HA calcifications identified on IMG3mm to those on IMGoutput with a slice thickness of 0.5 and 1.0 mm. Meanwhile, no statistically significant difference was found when comparing the HU values of 200-HA calcifications identified on IMG3mm to those on IMGoutput with a slice thickness of 1.5 mm. As for the rod inserts in CIRS phantoms simulating 9 different tissue types in human body, there was no statistically significant difference between IMG3mm and IMGoutput with slice thickness of 1.5 mm, and all the p values were larger than 0.10. With regards to patient study, more calcification pixels were detected on IMGoutput with a slice thickness of 1.5 mm than on IMG3mm, so calcifications were more clear on the denoised images. According to our results, the CNN-based denoising method could reduce statistical noise in IMGinput with a slice thickness of 1.5 mm without causing significant texture change or variation in HU values. The proposed method could improve cardiovascular risk prediction by detecting small and soft calcifications that are barely identified on 3-mm slice images used in conventional CAC scans.

Quantify total activity by volume-of-interest expansion with clinical SPECT/CT systems, a phantom study.

Quantitative measurements of activity in SPECT are important for radioisotope therapy planning and disease diagnosis. The aim of this manuscript is to develop a robust method to quantify the total activity in a volume-of-interest (VOI) of different quantitative SPECT reconstructions and validate the estimation accuracy. We customized an IEC body phantom using 3D printing technology and made six sphere inserts of 1-6cm in diameter with at least 3cm separation. The activity concentration within the spheres was in the range of patient lesion/organ activity. The background activity was then increased from zero to a sphere/background activity concentration of 8:1, 4:1, and 2:1. SPECT data were acquired with Philips Brightview and GE Discovery 670 SPECT/computed tomography (CT) systems under clinical acquisition protocols. Quantitative SPECT images were reconstructed with Hermes SUV-SPECT (both Philips and GE data) and GE Q.Metrix (GE data only). The quantitative SPECT reconstructions are iterative with scatter, CT attenuation correction, and resolution recovery. We quantified the total activity by expanding the sphere VOI to include a spill-out region. Background correction was applied by sampling a region outside the spill-out region. The true fractions (TFs) (total activity/true activity) were measured for all six spheres for all SPECT acquisitions. The TF is close to 100% for 2-6cm spheres for zero background, 8:1 and 4:1 sphere/background activity ratios. The TF was found to be unreliable for the 1-cm sphere because of the limit of phantom design. TF accuracy for 2:1 sphere/background ratio was degraded due to significantly large background, inadequate scatter correction and detector count loss. The results demonstrated that the proposed quantification method is accurate for objects of different sizes in currently clinical quantitative reconstruction and has the potential for improving the accuracy for therapeutic treatment planning or radiation dosimetry calculations.

Prostate-specific membrane antigen-directed imaging and radioguided surgery with single-photon emission computed tomography: state of the art and future outlook

ABSTRACT Introduction Prostate-specific membrane antigen (PSMA) has emerged as a highly relevant target for prostate cancer (PC) diagnosis and therapy. PSMA inhibitors targeting PSMA-enzymatic domain have been successfully labeled with radionuclides emitting positrons or gamma-photons, thus obtaining tracers suitable for imaging with positron emission computed tomography (PET/CT) or single-photon emission tomography (SPECT). Areas covered The different approaches for obtaining PSMA-ligands labeled with gamma-emitting nuclides (99mTc or111In) are reviewed. Furthermore, the applications of 99mTc/111In-PSMA SPECT for the imaging of PC patients in different clinical settings (staging or biochemical recurrence) are covered. Lastly, the employment of PSMA-targeted SPECT tracers for radioguided surgery (RGS) during primary or salvage lymphadenectomy is discussed. Expert opinion RGS provided satisfying preliminary results in both primary and salvage lymphadenectomy, allowing to discriminate between pathological and non-pathological nodes with high accuracy, although prospective studies with larger cohorts are needed to further validate this surgical approach. The potential of PSMA-targeted SPECT/CT has not been fully explored yet, but it might represent a relatively cost-effective alternative to PSMA PET/CT in limited resource environments. In this perspective, the implementation of novel SPECT technologies or algorithms, such as semiconductor-ionization detectors or resolution recovery reconstruction, will be topic of future investigation.

FastRoadSeg: Fast Monocular Road Segmentation Network

Monocular road segmentation is a fundamental component of autonomous driving. High accuracy has always been a focus of the community for this task. However, the exploration of high-speed methods is still lacking. This limits the prevalence of the monocular road segmentation method. In this paper, an efficient encoder-decoder network is proposed for segmenting the road from a single image. Specifically, to achieve high-speed inference, we leverage a shallow encoder for feature extraction and design a lightweight decoder for feature resolution recovery. To avoid the accuracy drop caused by network simplification, we introduce an efficient asymmetric dilated block to improve the ability of features to distinguish drivable/nondrivable roads to maintain the performance without excess computation. Experiments on three datasets verify the effectiveness of our method. On KITTI-Road, our approach ranks second among all monocular methods and even achieves a competitive performance compared to multimodal methods, with an inference speed over 135 FPS on a single TITAN Xp, which is at least 20 times faster than the state-of-the-art monocular method. Furthermore, our approach can be deployed on the embedded platform Jetson TX2 and achieves a speed of over 80 FPS. Codes will be available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/gongshichina/FastRoadSeg</uri> .

A Marked Low-Grade Inflammation and a Significant Deterioration in Metabolic Status in First-Episode Schizophrenia: A Five-Year Follow-Up Study.

The objective of this study was to evaluate how schizophrenia spectrum disorders and applied long-term (5.1 years) antipsychotic (AP) treatment affect the serum level of acylcarnitines (ACs), cytokines and metabolic biomarkers and to characterize the dynamics of inflammatory and metabolic changes in the early course of the disorder. A total of 112 adults participated in the study (54 patients with first-episode psychosis (FEP) and 58 control subjects). Biomolecule profiles were measured at the onset of first-episode psychosis and 0.6 years and 5.1 years after the initiation of APs. The results of the present study confirmed that specific metabolic–inflammatory imbalance characterizes AP-naïve patients. Short-term (0.6-years) AP treatment has a favourable effect on psychotic symptoms, as well as the recovery of metabolic flexibility and resolution of low-level inflammation. However, 5.1 years of AP treatment resulted in weight gain and increased serum levels of interleukin (IL)-2, IL-4, IL-6, IL-10, interferon-γ, hexoses, acetylcarnitine, short-chain ACs (C3, C4) and long-chain ACs (C16:2, C18:1, C18:2). In conclusion, despite the improvement in psychotic symptoms, 5.1 years of AP treatment was accompanied by a pronounced metabolic–inflammatory imbalance, which was confirmed by the presence of enhanced pro-inflammatory activity and increased obesity with changes in the metabolism of carbohydrates, lipids, and their metabolites.

Manganese-enhanced magnetic resonance imaging in Takotsubo syndrome

Abstract Background Takotsubo syndrome is an increasingly common acute cardiac emergency characterised by profound transient left ventricular systolic dysfunction following a stressful event. Its pathophysiology remains poorly understood and a third of patients will have a major adverse cardiac or cerebrovascular event by 5 years [1]. Defective myocardial calcium homeostasis is central to contractile dysfunction and may be implicated in its pathophysiology. Manganese-enhanced magnetic resonance imaging is a novel non-invasive imaging technique that assesses myocardial manganese uptake as a measure of myocardial calcium handling [2]. Our aim was to investigate myocardial calcium handling using manganese-enhanced magnetic resonance imaging during the acute and recovery phase of takotsubo syndrome. Methods This single centre case-controlled observational longitudinal cohort study was conducted in accordance with the Declaration of Helsinki and ethical committee approval with written informed consent. Twenty patients with takotsubo syndrome and 20 age, sex and cardiovascular risk factor matched volunteers were recruited between March 2020 and September 2021. Patients underwent gadolinium and manganese-enhanced magnetic resonance imaging during the index event with repeat manganese-enhanced magnetic resonance imaging after 3 months. Myocardial manganese uptake was characterised by Patlak modelling. Results During the acute presentation, most patients had an “apical” pattern of takotsubo syndrome with reduced left ventricular ejection fraction (51±11 versus 67±8%, P&amp;lt;0.001, Figure 1), elevated left ventricular mass (89±11 versus 57±14 g/m2, P&amp;lt;0.01) and native T1 (1358±49 versus 1211±28 ms, P&amp;lt;0.001) and T2 (60±7 versus 38±3 ms, P&amp;lt;0.001) values compared to matched volunteers. Patlak modelling demonstrated reduced myocardial manganese uptake (5.1±0.5 versus 8.0±1.0 mL/100g of tissue/min, P&amp;lt;0.0001) consistent with a major abnormality of myocardial calcium handling. Reduced myocardial manganese uptake attributable to apical takotsubo syndrome could be seen in one patient, scanned 18 days after symptom onset despite apparent resolution of cardiac function. Beyond 3 months of convalescence, left ventricular mass, ejection fraction, native T1 and T2 values were comparable to matched volunteers. Despite this, myocardial calcium handling remained abnormal compared to matched volunteers (6.7±0.7 versus 8.0±1.0 mL/100 g of tissue/min, P&amp;lt;0.001, Figure 2). Conclusions In patients with takotsubo syndrome, there is a profound perturbation of myocardial calcium handling which is most marked acutely but persists after apparent recovery of left ventricular ejection fraction and resolution of myocardial oedema. Abnormal myocardial calcium handling is implicated in the pathophysiology of takotsubo syndrome and manganese-enhanced magnetic resonance imaging could play a major role in the diagnosis and risk stratification of patients with takotsubo syndrome. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Medical Research CouncilBritish Heart Foundation

Machine Learning-Assisted Multifunctional Environmental Sensing Based on a Piezoelectric Cantilever.

Multifunctional environmental sensing is crucial for various applications in agriculture, pollution monitoring, and disease diagnosis. However, most of these sensing systems consist of multiple sensors, leading to significantly increased dimensions, energy consumption, and structural complexity. They also often suffer from signal interferences among multiple sensing elements. Herein, we report a multifunctional environmental sensor based on one single sensing element. A MoS2 film was deposited on the surface of a piezoelectric microcantilever (300 × 1000 μm2) and used as both a sensing layer and top electrode to make full use of the changes in multiple properties of MoS2 after its exposure to various environments. The proposed sensor has been demonstrated for humidity detection and achieved high resolution (0.3% RH), low hysteresis (5.6%), and fast response (1 s) and recovery (2.8 s). Based on the analysis of the magnitude spectra for transmission using machine learning algorithms, the sensor accurately quantifies temperatures and CO2 concentrations in the interference of humidity with accuracies of 91.9 and 92.1%, respectively. Furthermore, the sensor has been successfully demonstrated for real-time detection of humidity and temperature or CO2 concentrations for various applications, revealing its great potential in human-machine interactions and health monitoring of plants and human beings.

Positron range in combination with point-spread-function correction: an evaluation of different implementations for [124I]-PET imaging

AimTo evaluate the effect of combining positron range correction (PRC) with point-spread-function (PSF) correction and to compare different methods of implementation into iterative image reconstruction for 124I-PET imaging.Materials and methodsUniform PR blurring kernels of 124I were generated using the GATE (GEANT4) framework in various material environments (lung, water, and bone) and matched to a 3D matrix. The kernels size was set to 11 × 11 × 11 based on the maximum PR in water and the voxel size of the PET system. PET image reconstruction was performed using the standard OSEM algorithm, OSEM with PRC implemented before the forward projection (OSEM+PRC simplified) and OSEM with PRC implemented in both forward- and back-projection steps (full implementation) (OSEM+PRC). Reconstructions were repeated with resolution recovery, point-spread function (PSF) included. The methods and kernel variation were validated using different phantoms filled with 124I acquired on a Siemens mCT PET/CT system. The data was evaluated for contrast recovery and image noise.ResultsContrast recovery improved by 2–10% and 4–37% with OSEM+PRC simplified and OSEM+PRC, respectively, depending on the sphere size of the NEMA IQ phantom. Including PSF in the reconstructions further improved contrast by 4–19% and 3–16% with the PSF+PRC simplified and PSF+PRC, respectively. The benefit of PRC was more pronounced within low-density material. OSEM-PRC and OSEM-PSF as well as OSEM-PSF+PRC in its full- and simplified implementation showed comparable noise and convergence. OSEM-PRC simplified showed comparably faster convergence but at the cost of increased image noise.ConclusionsThe combination of the PSF and PRC leads to increased contrast recovery with reduced image noise compared to stand-alone PSF or PRC reconstruction. For OSEM-PRC reconstructions, a full implementation in the reconstruction is necessary to handle image noise. For the combination of PRC with PSF, a simplified PRC implementation can be used to reduce reconstruction times.

Multiple-pinhole collimators improve intra- and between-rater agreement and the certainty of the visual interpretation in dopamine transporter SPECT

BackgroundMultiple-pinhole (MPH) collimators improve the resolution–sensitivity trade-off compared to parallel-hole collimators. This study evaluated the impact of MPH collimators on intra- and between-rater agreement, and on the certainty of visual interpretation in dopamine transporter (DAT)-SPECT.MethodsThe study included 71 patients (62.1 ± 12.7 y). Two SPECT acquisitions were performed in randomized order after a single injection of 182 ± 9 MBq 123I-FP-CIT, one with MPH and one with low-energy–high-resolution–high-sensitivity (LEHRHS) collimators. MPH projections were reconstructed with an iterative 3d Monte Carlo algorithm. LEHRHS projections were reconstructed with filtered backprojection (FBP) or with ordered-subsets expectation–maximization and resolution recovery (OSEM). Images were visually evaluated twice by three independent raters with respect to presence/absence of Parkinson-typical reduction of striatal 123I-FP-CIT uptake using a Likert 6-score (− 3 = clearly normal, …, 3 = clearly reduced). In case of intra-rater discrepancy, an intra-rater consensus was obtained. Intra- and between-rater agreement with respect to the Likert score (6-score and dichotomized score) was characterized by Cohen’s kappa.ResultsIntra-rater kappa of visual scoring of MPH/LEHRHS-OSEM/LEHRHS-FBP images was 0.84 ± 0.12/0.73 ± 0.06/0.73 ± 0.08 (6-score, mean of three raters) and 1.00 ± 0.00/0.96 ± 0.04/0.97 ± 0.03 (dichotomized score). Between-rater kappa of visual scoring (intra-rater consensus) of MPH/LEHRHS-OSEM/LEHRHS-FBP images was 0.70 ± 0.06/0.63 ± 0.08/0.48 ± 0.05 (6-score, mean of three pairs of raters) and 1.00 ± 0.00/0.92 ± 0.04/0.90 ± 0.06 (dichotomized score). There was a decrease of (negative) Likert scores in normal DAT-SPECT by 0.87 ± 0.18 points from the LEHRHS-OSEM to the MPH setting. The (positive) Likert scores of reduced DAT-SPECT did not change on average.ConclusionsMPH collimators improve intra- and between-rater agreement as well as the certainty of the visual interpretation of DAT-SPECT.

Successful Retreatment With Venetoclax in a Patient With Chronic Lymphocytic Leukemia.

Successful Retreatment With Venetoclax in a Patient With Chronic Lymphocytic Leukemia.

Effect of diabetes on efferocytosis process

Diabetes is a complex of genetic, metabolic, and autoimmune disorders that are characterized by hyperglycemia. Elevated apoptotic cell count following defective clearance of dead cells that can cause chronic inflammation is a hallmark of the diabetic wound. Effective dead cell clearance is a prerequisite for rapid inflammation resolution and successful recovery. Efferocytosis is a multistep process in which phagocytes engulf the dead cells. Cell body elimination is of great significance in disease and homeostasis. Recent research has clarified that diabetic wounds have an enhanced load of the apoptotic cell, which is partly attributed to the dysfunction of macrophages in apoptotic clearance at the site of the diabetic wounds. In the current work, we highlight the pathways implicated in efferocytosis, from the diagnosis of apoptotic cells to the phagocytic swallowing and the homeostatic resolution, and explain the possible pathophysiological episodes occurring when the proceeding is abrogated. Also, we describe the last development in the management of inflammation in diabetes wound and future directions of surveillance.

Experimental evaluation of absolute quantification in 99m Tc-TRODAT-1 SPECT/CT brain dopamine transporter (DAT) studies.

ObjectiveTo evaluate the quantitative accuracy of clinical brain dopamine transporters (DAT) investigations utilizing 99mTc‐TRODAT‐1 single‐photon emission computed tomography (SPECT)/computed tomography (CT) in experimental and clinical settings.Materials and methodsThe study used an experimental phantom evaluation and a clinical dataset. Three‐dimensional‐ordered subsets expectation–maximization reconstructed the original and resampled datasets using attenuation correction, scatter correction, and resolution recovery. The reconstructed data were analyzed and reported as percentage difference, standardized uptake value reference (SUVr), and a coefficient of variation (CoV). The Taguchi method tested the impact of the three different parameters on signal‐to‐noise ratio (SNR) and SUVr, including number iteration, Poisson resampling, and phantom setup, with and without the plaster of Paris (POP). Six 99mTc‐TRODAT‐1 SPECT/CT scans were acquired in healthy subjects for verification purposes.ResultsThe percentage activity difference between the phantom with and without POP is 20% and 5%, respectively. The SUVr reveals a 10% underestimate for both with and without POP. When it comes to the influence of Poisson resampling, the SUVr value for 75% Poisson resampling indicates 10% underestimation on both sides of the caudate and putamen area, with and without POP. When 25% of Poisson resampling is applied, the SUVr value is overestimated (±35%). In the Taguchi analysis, iteration numbers were the most dominant factor with the F‐value of 9.41 and the contribution rate of 52.66% (p < 0.05) for SNR. In comparison, F‐value of 9.1 for Poisson resampled with contribution rate of 58.91% (p < 0.05) for SUVr. Reducing counts by 25% from the original dataset resulted in a minimal bias in SUVr, compared to 50% and 75%.ConclusionThe optimal absolute SPECT/CT quantification of brain DAT studies using 99mTc‐TRODAT‐1 appears achievable with at least 4i10s and SUVr as the surrogate parameter. In clinical investigations, it is possible to reduce the recommended administered dose by up to 25% while maintaining accurate measurement.

Paper 89: Ultrasound-guided Glenohumeral Corticosteroid Injection for the Treatment of Adhesive Capsulitis of the Shoulder: The Role of Clinical Stage in Response to Treatment

Objectives:The treatment for idiopathic adhesive capsulitis of the shoulder remains controversial. The pathophysiology of adhesive capsulitis supports the rationale for intra-articular glenohumeral joint corticosteroid injection to treat the synovial inflammation in stages 1 and 2, that results in capsular fibrosis in the later stages of adhesive capsulitis. We hypothesize that an intra-articular ultrasound-guided glenohumeral injection (USGI) of corticosteroid in patients diagnosed with stage 1 or stage 2 idiopathic adhesive capsulitis will result in timely functional recovery and resolution of pain and stiffness.Methods:This is a retrospective analysis of a cohort of patients with stage 1 or stage 2 idiopathic adhesive capsulitis, diagnosed using history and physical examination. A total of 61 patients met inclusion criteria. Range of motion (ROM) measurements documented in the patient charts were recorded in four planes: forward flexion, abduction, internal rotation, and external rotation in neutral abduction. All ROM measurements were performed pre-injection and at all subsequent post-injection visits by a single treating physician. All patients were treated with an ultrasound-guided intra-articular injection of local anesthetic and depomedrol. Recovery criteria were defined as forward flexion, abduction, and external rotation to within 15 degrees of the contralateral side and internal rotation to within three spinous process levels of the contralateral side.Results:A total of 11 patients with Stage 1 and 50 patients with Stage 2 adhesive capsulitis comprised the study cohort. The mean age was 55 years (SD=8, range: 38 to 72) and 49 (80%) patients were female. Within the stage 1 cohort, all 11 patients met recovery criteria for forward flexion (100%), 10 patients met recovery criteria for abduction (91%), 11 patients met recovery criteria for internal rotation (100%), and 8 patients met recovery criteria for external rotation (73%). Within the stage 2 cohort, 31 patients met recovery criteria for forward flexion (62%), 30 patients met recovery criteria for abduction (60%), 36 patients met recovery criteria for internal rotation (72%), and 24 patients met recovery criteria for external rotation (48%). Time to recovery in days for each ROM compared between the stage 1 and stage 2 cohorts was statistically significant in all ROM planes (forward flexion (p<0.0001), abduction (p<0.0001), internal rotation (p=0.0008), and external rotation (p=0.0096)), indicating a greater proportion of stage 1 patients had a shorter time to recovery after injection. Figures 1-4 depict cumulative survival functions between Stage 1 and Stage 2 patients for each individual ROM measurement.Conclusions:USGI for early adhesive capsulitis allows patients to recover ROM more rapidly. Importantly, Stage 1 patients recovered faster than Stage 2 patients in all ROM planes, with only forward flexion reaching statistical significance. This suggests that prompt recognition of early idiopathic adhesive capsulitis and subsequent USGI with corticosteroid and local anesthetic plays an important role in timely recovery of motion and symptom resolution thus shortening the natural history of this disease and preventing the development of significant fibrosis.Figure 1.Cumulative survival functions between Stage 1 and Stage 2 patients for Forward FlexionFigure 2.Cumulative survival functions between Stage 1 and Stage 2 patients for AbductionFigure 3.Cumulative survival functions between Stage 1 and Stage 2 patients for Internal RotationFigure 4.Cumulative survival functions between Stage 1 and Stage 2 patients for External Rotation