Reconstruction Protocols Research Articles

Impact of Gabapentin on Postoperative Hypotension in Enhanced Recovery after Surgery Protocols for Microvascular Breast Reconstruction.

Enhanced recovery after surgery (ERAS) protocols have been associated with hypotensive episodes after autologous breast reconstruction. Gabapentin (Gaba), a nonopioid analgesic used in ERAS, has been shown to attenuate postoperative hemodynamic responses. This study assesses ERAS's impact, with and without Gaba, on postoperative hypotension after microvascular breast reconstruction. Three cohorts were studied: traditional pathway, ERAS + Gaba, and ERAS no-Gaba. We evaluated length of stay, inpatient narcotic use [morphine milligram equivalents (MME)], mean systolic blood pressure, hypotension incidence, and complications. The traditional cohort was retrospectively reviewed, whereas the ERAS groups were enrolled prospectively after the initiation of the protocol in April 2019 (inclusive of Gaba until October 2022). In total, 441 patients were analyzed. The three cohorts, in the order mentioned above, were similar in age and bilateral reconstruction rates (57% versus 61% versus 60%). The ERAS cohorts, both with and without Gaba, had shorter stays (P < 0.01). Inpatient MME was significantly less in the ERAS + Gaba cohort than the traditional or ERAS no-Gaba cohorts (medians: 112 versus 178 versus 158 MME, P < 0.01). ERAS + Gaba significantly increased postoperative hypotensive events on postoperative day (POD) 1 and 2, with notable reduction after Gaba removal (P < 0.05). Across PODs 0-2, mean systolic blood pressure was highest in the traditional cohort, followed by ERAS no-Gaba, then the ERAS + Gaba cohort (P < 0.05). Complication rates were similar across all cohorts. Postmicrovascular breast reconstruction, ERAS + Gaba reduced overall inpatient narcotic usage, but increased hypotension incidence. Gaba removal from the ERAS protocol reduced postoperative hypotension incidence while maintaining similar stay lengths and complication rates.

Comparison of a 3D CZT and conventional SPECT/CT system for quantitative Lu-177 SPECT imaging

PurposeNext-generation SPECT/CT systems with CdZnTe (CZT) digital detectors in a ring-like setup are emerging to perform quantitative Lu-177 SPECT imaging in clinical routine. It is essential to assess how the shorter acquisition time might affect the image quality and uncertainty on the mean absorbed dose of the tumors and organs at risk compared to a conventional system.Methods A NEMA Image Quality phantom was scanned with a 3D CZT SPECT/CT system (Veriton, by Spectrum Dynamics) using 6 min per bed position and with a conventional SPECT/CT system (Symbia T16, by Siemens) using 16 min per bed position. The sphere-to-background ratio was 12:1 and the background activity concentration ranged from 0.52 to 0.06 MBq/mL. A clinical reconstruction protocol for dosimetry purposes was determined for both systems by maximizing the sphere-to-background ratio while keeping the coefficient of variation of the background as low as possible. The corresponding image resolution was determined by the matching filter method and used for a dose uncertainty assessment of both systems following an established uncertainty model..ResultsThe optimized iterative reconstruction protocol included scatter and attenuation correction for both systems and detector response modeling for the Siemens system. For the 3D CZT system, 6 iterations and 8 subsets were combined with a Gaussian post-filter of 3 mm Full Width Half Maximum (FWHM) for post-smoothing. For the conventional system, 16 iterations and 16 subsets were applied with a Gaussian post-smoothing filter of 1 mm FWHM. For these protocols, the sphere-to-background ratio was 18.5% closer to the true ratio for the conventional system compared to the 3D CZT system when considering the four largest spheres. Meanwhile, the background coefficient of variation was very similar for both systems. These protocols resulted in SPECT image resolution of 14.8 mm and 13.6 mm for the 3D CZT and conventional system respectively. Based on these resolution estimates, a 50% dose uncertainty corresponded to a lesion volume of 28 mL for the conventional system and a lesion volume of 33 mL for the 3D CZT system. ConclusionsAn optimized reconstruction protocol for a Veriton system with 6 min of acquisition time per bed position resulted in slightly higher dose uncertainties than a conventional Symbia system using 16 min of acquisition time per bed position. Therefore, a 3D CZT SPECT/CT allows to significantly reduce the acquisition times with only a very limited impact on dose uncertainties such that quantitative Lu-177 SPECT/CT imaging becomes much more accessible for treatment concurrent dosimetry. Nevertheless, the uncertainty of SPECT-based dose estimates remains high.

Enhanced Recovery After Surgery in Immediate DIEP Flap Breast Reconstruction: Reducing Length of Stay and Opioid Use

Background: To improve patient outcomes amid reduced healthcare resources during the COVID-19 pandemic, a single Canadian cancer center implemented an Enhanced Recovery After Surgery (ERAS) protocol for autologous DIEP flap breast reconstruction. Methods: This retrospective cohort study included 100 consecutive patients undergoing microsurgical breast reconstruction with DIEP flaps using the ERAS protocol and 100 patients using a standard protocol. Primary outcomes were the hospital length of stay and opioid use. Secondary outcomes included postoperative complications, laxative and antiemetic consumption. Results: In this study, 80% of the patients had immediate reconstruction, while the remaining patients received either delayed immediate or delayed reconstruction. Patients in the ERAS group had shorter hospital stays (2.8 vs 4.5 days; P &lt; 0.001) and lower total opioid use (50.2 vs 136.3 mg; P &lt; 0.001). This reduction was also observed when breaking down opiates per day of hospitalization (30.2 vs 18.2 mg; P &lt; 0.001), and in the first 24 postoperatively hours (35.7 vs 67.6 mg; P &lt; 0.001). The control group had a higher incidence of postoperative complications, including seroma, partial and total flap necrosis, compared to the ERAS group. However, readmission rates were similar between the two groups. Conclusion: Implementing the ERAS protocol for DIEP flap breast reconstruction can significantly reduce hospital length of stay and postoperative opioid requirements without increasing the risk of adverse events. This pattern holds true for immediate reconstructions with DIEP flaps.

Optimisation of the bone single photon emission computed tomography in oncology patients

Introduction: The introduction of hybrid imaging systems such as Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) has completely changed the scanning procedure of conventional diagnostic nuclear medicine protocols. Modern bone scintigraphy protocols include SUV quanitification and Whole Body (WB) SPECT/CT scanning modality. The major limitation of these new technologies is relatively long scanning time. New detector systems with modern reconstruction softwares have been developed for fast scanning SPECT protocolos. These new technologies can produce images of reduced acquisition with same quality as full scanning acquisition. As a result new studies suggest that planar WB scintigraphy should be replaced with WB SPECT/CT. Methods: One hundred oncology patients performed SPECT/CT as a part as their clinical follow-up. Three different scanning and three reconstruction protocols have been evaluated. Two nuclear medicine physicians evaluated with Likert scale image sharpness, lesion visibility, and lesion background detectability. The overall image quality was determined as the sum of these three parameters. Results: In terms of scan duration reduction on image quality, Volumetrix Evolution for Bone performed during ultra-fast SPECT acquisition achieved the highest score, which is superior compared to the standard SPECT acquisition protocol. The overall image quality was the best with the Volumetrix MI Evolution for Bone protocol for ultra-fast acquisition Conclusion: The Evolution for Bone protocol for ultra-fast acquisition showed best results compared to other protocols. The adoption of new acquisition SPECT protocol may offer more comfortable exams, resulting in higher patient satisfaction. The implementation of this new protocol can lead to an improvement in SPECT sensitivity, primarily due to the reduction of SPECT motion artifacts.

Functional outcomes of accelerated rehabilitation protocol for anterior cruciate ligament reconstruction in amateur athletes: a randomized clinical trial.

Anterior cruciate ligament (ACL) rupture is the most common knee injury among athletes, and can result in long-term complications and career-ending conditions for sportspeople. There is no consensus in the literature on the effectiveness of rehabilitation after ACL reconstruction, or the best protocol to follow for functional outcome improvement. To determine the impact of an accelerated rehabilitation protocol on knee functional outcomes in amateur athletes with anterior cruciate ligament reconstruction (ACLR). Two-arm, parallel-group randomized comparative design. A total of 100 amateur male athletes (mean age 22.01 ± 1.79 years) with ACLR were randomly divided into experimental and control groups (n = 50/group). An accelerated rehabilitation protocol and a conventional rehabilitation protocol were used for the experimental group. In contrast, only the conventional rehabilitation protocol was used for the control group. The rehabilitation was delivered in 5 weekly sessions for 22 weeks. The primary outcome measure, knee pain, was measured using a visual analogue scale (VAS). Extensive test batteries, for hop tests, Knee Injury and Osteoarthritis Outcome Score (KOOS), and knee effusion, were measured, aiming to add more objective criteria to determine functional performance. Both groups (n = 50/group) were well-matched (p = 0.816), with insignificant differences in their demographic characteristics (p > 0.05). A multivariate analysis of variance (MANOVA) test showed no significant difference between the 2 groups (p = 0.781) at baseline. A 2-way MANOVA (2 × 2 MANOVA) of within- and between-group variations indicated overall significant treatment, time, and treatment × time interaction effects (p < 0.001) in favour of the accelerated rehabilitation group. The accelerated rehabilitation protocol was more effective in improving functional outcomes than a conventional rehabilitation protocol in amateur athletes with ACLR.

Development and application of a 3D image analysis strategy for focused ion beam - Scanning electron microscopy tomography of porous soft materials.

In recent years, the potential of porous soft materials in various device technologies has increased in importance due to applications in fields, such as wearable electronics, medicine, and transient devices. However, understanding the 3-dimensional architecture of porous soft materials at the microscale remains a challenge. Herein, we present a method to structurally analyze soft materials using Focused Ion Beam - Scanning Electron Microscopy (FIB-SEM) tomography. Two materials, polymethyl methacrylate (PMMA) membrane and pine wood veneer were chosen as test-cases. FIB-SEM was successfully used to reconstruct the true topography of these materials in 3D. Structural and physical properties were subsequently deduced from the rendered 3D models. The methodology used segmentation, coupled with optimized thresholding, image processing, and reconstruction protocols. The 3D models generated pore size distribution, pore inter-connectivity, tortuosity, thickness, and curvature data. It was shown that FIB-SEM tomography provides both an informative and visual depiction of structure. To evaluate and validate the FIB-SEM reconstructions, porous properties were generated from the physical property analysis techniques, gas adsorption analysis using Brunauer-Emmett-Teller (BET) surface area analysis and mercury intrusion porosimetry (MIP) analysis. In general, the data obtained from the FIB-SEM reconstructions was well-matched with the physical data. RESEARCH HIGHLIGHTS: Porous specimens of both synthetic and biological nature, a poly(methyl methacrylate) membrane and a pine veneer respectively, are reconstructed via FIB-SEM tomography without resin-embedding. Different thresholding and reconstruction methods are explored whereby shadowing artifacts are present with the aid of free open-source software. Reconstruction data is compared to physical data: MIP, gas adsorption isotherms which are analyzed via BET and Barrett-Joyner-Halenda (BJH) analysis to yield a full picture of the materials.

Acceptance of outpatient enhanced recovery after surgery (ERAS©) protocols for implant-based breast reconstruction nudged on by the COVID-19 pandemic

We retrospectively identified 295 women undergoing outpatient implant breast reconstruction (IBR) who received standardized ERAS care pre-pandemic (PP; April 2018–March 2020) and during the pandemic (DP; April 2020–March 2022). The majority of IBR was completed as outpatient surgeries DP versus PP (73% versus 38%, p < 0.001). Immediate IBR increased DP versus PP (p < 0.001). Preoperative ERAS© order sets were used 54% of the time. Lack of ERAS© order set use was associated with unplanned admissions (55.3% versus 44.7%, p = 0.02). COVID-19 changed health care and nudged IBR to outpatient procedures. With ERAS© recommendations, IBR can be safely and effectively transitioned to outpatient settings.

Feasibility study to characterize the production of antineutrons in high energy pp collisions through charge exchange interactions

Simulations to evaluate the feasibility of antineutron identification and kinematic characterization via the hadronic charge exchange (CEX) interaction n+n¯→p+p¯ are reported. The target neutrons are those composing the silicon nuclei of which inner tracking devices present in the Large Hadron Collider experiments ALICE, ATLAS, and CMS. Simulations of pp collisions in PYTHIA were carried out at different energies to investigate n¯ production and energy spectra. These simulations produced a decreasing power-law n¯ energy spectra. Then, two types of GEANT4 simulations were performed, placing an n¯ point source at the ALICE primary vertex, as a working example. In the first simulation, the kinetic energy E k was kept at an arbitrary (1 GeV) fix value to develop an n¯ identification and kinematics reconstruction protocol. The second GEANT4 simulation used the resulting PYTHIA at spp=13 TeV n¯ energy spectra. In both GEANT4 simulations, the occurrence of CEX interactions was identified by the unique outgoing p¯ . The simplified simulation allowed to estimate a 0.11% CEX-interaction identification efficiency at E k = 1 GeV. The p CEX-partner identification is challenging because of the presence of silicon nucleus-fragmentation protons. Momentum correlations between the n¯ and all possible p¯p pairs showed that p CEX-partner identification and n¯ kinematics reconstruction corresponds to minimal momentum-loss events. The use of inner tracking system dE/dx information is found to improve n¯ identification and kinematic characterization in both GEANT4 simulations. The final protocol applied to the realistic GEANT4 simulation resulted in a n¯ identification and kinematic reconstruction efficiency of 0.006%, based solely on p¯p pair observable. If applied to the ALICE minimum-bias RUN2 pp at spp=13 TeV data sample, this technique is found to have the potential to identify and reconstruct the kinematics of 4.3×108n¯ 's, illustrating the feasibility of the method.

The D-SPECT SH reconstruction protocol: improved quantification of small left ventricle volumes

BackgroundDue to spatial resolution limitations, conventional NaI-SPECT typically overestimates the left ventricular (LV) ejection fraction (EF) in patients with small LV volumes. The purpose of this study was to explore the clinical application value of the small heart (SH) reconstruction protocol embedded in the postprocessing procedure of D-SPECT.MethodsWe retrospectively analyzed patients who undergo both D-SPECT and echocardiography (Echo) within one week. Patients with small LV volume were defined as those with a rest end-systolic volume (rESV) ≤ 25 mL and underwent reconstruction using the standard (SD) reconstruction protocol. The SH protocol was deemed successful in correcting the LVEF value if it decreased by 5% or more compared to the SD protocol. The ROC curve was used to calculate the optimal cutoff value of the SH protocol. LVEF, ESV and EDV were computed with SD and SH, respectively. Echo was performed as a reference, and Echo-LVEF, ESV, and EDV were calculated using the Teichholz formula. One-way ANOVA was used to compare these parameters among the three groups.ResultsThe final study included 209 patients (73.21% female, age 67.34 ± 7.85 years). Compared with the SD protocol, the SH protocol significantly decreased LVEF (67.43 ± 7.38% vs. 71.30 ± 7.61%, p < 0.001). The optimal cutoff value for using the SH protocol was rESV > 17 mL (AUC = 0.651, sensitivity = 78.43%, specificity = 45.57%, p = 0.001). In the subgroup of rESV > 17 mL, there was no significant difference in LVEF (61.84 ± 4.67% vs. 62.83 ± 2.85%, p = 0.481) between the SH protocol and Echo, and no significant difference was observed in rESV (26.92 ± 3.25 mL vs. 27.94 ± 7.96 mL, p = 0.60) between the SH protocol and Echo.ConclusionThis pilot study demonstrated that the SH reconstruction protocol was able to effectively correct the overestimation of LVEF in patients with small LV volumes. Particularly, in the rESV > 17 mL subgroup, the time and computing power waste could be reduced while still ensuring the accuracy of the LVEF value and image quality.

Body Contour in the Post-Bariatric Male Patient

Background: Obesity is currently considered a public health problem. Bariatric procedures have become an important part of obesity management and, consequently, the number of male patients seeking post-bariatric reconstructive procedures have increased. Therefore, the clinical approach and understanding of the body contour of this population have become more relevant. The goal of post-bariatric reconstruction is to enhance the male silhouette through removal of skin and adipose tissue excess, and abdominal rectus diastasis repair. Material and Methods: We conducted a retrospective study at the Plastic and Reconstructive Surgery Department of the National Medical Center “20 de Noviembre”. All male patients referred to our department to start a post-bariatric reconstruction protocol from January 2018 to December 2022 were included in this study. Results: In total, 15 patients who underwent corporal contouring procedures were included; median age was 49.2 years with minimum of 33 years, and a maximum of 57 years. Median Body mass index was 28.4 kg/m2 with minimum of 22 kg/m2 and maximum of 38 kg/m2 . All patients were treated 18 months after their bariatric surgery. All patients underwent an abdominoplasty as a body contouring procedure. 4 (26.7%) patients presented complications related to the surgery. Conclusion: We propose a comprehensive and systematic approach to massive weight loss for male patients, suggesting an abdominal marking based on the patient's clinical features and the expected results avoiding feminization of the abdominal body contour.

The “Double Wing” titanium mesh anterior skull base reconstruction protocol for challenging contexts within the transbasal approach: technical description and efficacy

The “Double Wing” titanium mesh anterior skull base reconstruction protocol for challenging contexts within the transbasal approach: technical description and efficacy

Impact of Attenuation Correction, Collimator, and Iterative Reconstruction Protocols on 67Ga SPECT/CT Quantification

Purpose: The main goal of this study was to determine the optimal collimator in the absence of medium energy collimators along with the impact of Attenuation Correction (AC) and different iterative reconstruction protocols on the quantitative evaluation of Gallium-67 (67Ga) SPECT/CT imaging.&#x0D; Materials and Methods: A GE Discovery 670 dual-head SPECT/CT scanner and a NEMA phantom filled with 67Ga solution were used to scan the patients. The projections were acquired with both Low Energy High Resolution (LEHR) and High Energy General Purpose (HEGP) collimators, and CT images were acquired to evaluate the effect of attenuation correction. SPECT data were reconstructed using the ordered subset expectation maximization (OSEM) method with various combinations of iterations and subsets. The performance was quantified, and a clinical study validated the phantom study.&#x0D; Results: Acquired images by the HEGP collimator yielded higher Contrast Recovery (CR) and Contrast to Noise Ratio (CNR) in images with AC than those without non-AC (41.6% and 74.2%, respectively). The CNR in all spheres after AC was increased by 80.4% (82.1%) for the HEGP collimator against the LEHR collimator. Also, an increase in iterations × subsets from 16 to 48 led to the Coefficient of Variation (COV) increasing by 17.2%, 16.67%, 15.50%, 14.4%, 14.2%, and 14.1% for 10 mm to 37 mm sphere diameter, respectively.&#x0D; Conclusion: CT-based AC and HEGP collimators can yield improved 67Ga SPECT quantification compared to Non-AC and LEHR collimators. The choice of the optimal collimator with the reconstruction protocol led to changes in the image quality and quantitative accuracy, emphasizing the need to carefully select the appropriate combination of data acquisition factors.&#x0D;

Reasons for the Variability of Rehabilitation Programs and the Perspective of the Standardized Guidelines Development for Patients after Anterior Cruciate Ligament Reconstruction

Summary. The following factors influence the choice of rehabilitation program after anterior cruciate ligament (ACL) reconstruction. Surgical factors: peculiarities of the tunnels drilling, method and quality of graft fixation, presence and type of additional distal fixation, as well as the presence or absence of additional reinforcement, graft diameter, graft material and quality, graft suturing method, type of ACL repair (single- or double-bundle), and other elements of the surgery. Patient factors: compliance, psychological readiness to move on to the next phase of rehabilitation, goals and objectives set by the patient; age, type, and level of activity and physical condition of the patient; motivation, expectations of the patient, the preoperative experience of the patient in performing rehabilitation exercises, weight and height of the patient, body proportions, in particular of the lower limb segments (different lever lengths), rotational and axial allignment of the lower limb bones, posterior tibial plateau slope, intercondylar notch width and notch roof slope, condition of the anterolateral ligament and other knee joint stabilizers, muscle tone and strength in general and at the time of surgery in particular, range of motion in the knee and adjacent joints. Given the need to consider at least the above factors, there should not be a single rehabilitation protocol for ACL reconstruction. Only close cooperation between the surgeon, rehabilitologist and physical therapist allows for the fastest and safest rehabilitation of such patients. The patient's subjective feelings and their ability to perform specific exercises are not the criteria for deciding to proceed to the next rehabilitation phase. There is a certain limit, determined by the speed of biological processes in the body, which we cannot yet overcome. It is a good practice for the surgeon to fill out a patient's rehabilitation card immediately after the surgery, indicating the exercises, the time they should start, and the allowed loads.

Five-Year Follow-Up of 8 and 6 mm Locking-Taper Implants Treated with a Reconstructive Surgical Protocol for Peri-Implantitis: A Retrospective Evaluation

Peri-implant infections, in the absence of adequate treatment, can finally lead to premature loss of the implant. Among targeted protocols recently proposed for the treatment of peri-implant bone defects, and in the case of short implants, reconstructive surgery represents a recommended option. The purpose of this study was to evaluate the outcomes, in terms of maintenance, of a reconstructive treatment for peri-implantitis in locking-taper plateau-design single-crown implants, followed for 5 years after surgery. A retrospective evaluation was conducted in 20 patients treated with access flap surgery, concomitant chemical and mechanical surface decontamination, and bone grafting (using a self-hardening mixture of bone substitutes and biphasic calcium sulfate without the use of membranes). Of the 21 implants assessed, 9 were 8 mm-length, and 12 were 6 mm-length. Implant loss and treatment success were, respectively, 0% and 80.95% after 5 years from surgery. All parameters related to bone levels and soft tissue conditions significantly improved after 3 years and remained stable at the 5-year follow-up. The proposed protocol, followed by an effective supporting periodontal therapy, demonstrated the maintenance of the function of all implants, providing adequate stability during the healing process after surgery and limiting the onset of disease recurrence.

Quantum Secret Reconstruction

AbstractIn addition to secret splitting, secret reconstruction is another important component of secret sharing. In this paper, the first quantum secret reconstruction protocol is proposed to protect the reconstruction process. Before the protocol, a classical secret is divided into multiple shares that are distributed to the shareholds, respectively. In the presented protocol, the dealer utilizes the secret to encrypt a privacy quantum state, and sends the encrypted state to a combiner who is chosen by the dealer within the shareholders. With the help of other shareholders, the combiner utilizes the properties of cluster states to recover the privacy quantum state. It is shown that the proposed protocol is secure against several common attacks, including external and internal attacks. Compared with classical secret reconstruction protocols, this protocol not only achieves information‐theoretic security of all shares, but is also more efficient due to the reduced distribution and computation cost. To demonstrate the feasibility of the protocol, a corresponding simulation quantum experiment is conducted on the IBM Q. Furthermore, in conjunction with quantum fingerprinting, it can be directly applied to achieve the task of quantum multiple secrets sharing, since the classical shares can be reused in the proposed protocol.

Optimisation of the air fraction correction for lung PET/CT: addressing resolution mismatch

BackgroundIncreased pulmonary 18\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{18}{}$$\\end{document}F-FDG metabolism in patients with idiopathic pulmonary fibrosis, and other forms of diffuse parenchymal lung disease, can predict measurements of health and lung physiology. To improve PET quantification, voxel-wise air fractions (AF) determined from CT can be used to correct for variable air content in lung PET/CT. However, resolution mismatches between PET and CT can cause artefacts in the AF-corrected image.MethodsThree methodologies for determining the optimal kernel to smooth the CT are compared with noiseless simulations and non-TOF MLEM reconstructions of a patient-realistic digital phantom: (i) the point source insertion-and-subtraction method, hpts\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{pts}$$\\end{document}; (ii) AF-correcting with varyingly smoothed CT to achieve the lowest RMSE with respect to the ground truth (GT) AF-corrected volume of interest (VOI), hAFC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{AFC}$$\\end{document}; iii) smoothing the GT image to match the reconstruction within the VOI, hPVC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{PVC}$$\\end{document}. The methods were evaluated both using VOI-specific kernels, and a single global kernel optimised for the six VOIs combined. Furthermore, hPVC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{PVC}$$\\end{document} was implemented on thorax phantom data measured on two clinical PET/CT scanners with various reconstruction protocols.ResultsThe simulations demonstrated that at <200\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<200$$\\end{document} iterations (200 i), the kernel width was dependent on iteration number and VOI position in the lung. The hpts\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{pts}$$\\end{document} method estimated a lower, more uniform, kernel width in all parts of the lung investigated. However, all three methods resulted in approximately equivalent AF-corrected VOI RMSEs (<10%) at ≥\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\ge$$\\end{document}200i. The insensitivity of AF-corrected quantification to kernel width suggests that a single global kernel could be used. For all three methodologies, the computed global kernel resulted in an AF-corrected lung RMSE <10% at ≥\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\ge$$\\end{document}200i, while larger lung RMSEs were observed for the VOI–specific kernels. The global kernel approach was then employed with the hPVC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{PVC}$$\\end{document} method on measured data. The optimally smoothed GT emission matched the reconstructed image well, both within the VOI and the lung background. VOI RMSE was <10%, pre-AFC, for all reconstructions investigated.ConclusionsSimulations for non-TOF PET indicated that around 200i were needed to approach image resolution stability in the lung. In addition, at this iteration number, a single global kernel, determined from several VOIs, for AFC, performed well over the whole lung. The hPVC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$h_{PVC}$$\\end{document} method has the potential to be used to determine the kernel for AFC from scans of phantoms on clinical scanners.

Coronary artery calcium scoring assessment in ultra-low-dose chest computed tomography

ObjectivesTo investigate the effect of non-electrocardiogram (ECG) -triggered ultra-low-dose CT (ULD-CT) with different reconstruction protocols on coronary artery calcium (CAC) scoring assessment, compared with ECG-triggered CAC CT (CAC-CT). MethodsThis prospective study included 115 patients who underwent CAC-CT and ULD-CT scans under the same topogram images. CAC-CT adopted a prospective ECG-triggered sequential acquisition with a tube potential of 120 kV, and the reconstruction protocol was standard Qr36 + slice 3 mm (CACQr-3mm group). ULD-CT adopted a non-ECG-triggered high-pitch acquisition with a tube potential of Sn100 kV, and four groups of images (named ULDQr-3mm, ULDSa-3mm, ULDQr-1.5mm, and ULDSa-1.5mm) were reconstructed using different reconstruction algorithms (standard Qr36, kV-independent Sa36) and slice thicknesses (3 mm, 1.5 mm). The accuracy of CAC detection by ULD-CT was calculated. The agreement of the CAC score between ULD-CT and CAC-CT scans was assessed using intraclass correlation coefficients (ICC) and Bland-Altman plot, and the agreement of risk categorization was assessed using weighted kappa. ResultsThe sensitivity and specificity of the ULDSa-1.5mm group for detecting positive CAC were 100% and 97.4%, respectively (k = 0.980). The CAC score for the ULDSa-3mm and ULDSa-1.5mm groups demonstrated excellent agreement with the CACQr-3mm group (ICC = 0.992, 0.990, respectively), with a mean difference of −12.3 and − 12.4. The agreement of risk categorization based on absolute and percentile CAC score between the ULDSa-1.5mm and CACQr-3mm groups was excellent (weighted k = 0.954, 0.983, respectively), and risk reclassification rates were low (3.5%, 2.8%, respectively). The effective dose was reduced by approximately 77.2% for the ULD-CT compared to the CAC-CT (0.18 mSv vs. 0.79 mSv, p < 0.001). ConclusionReconstruction with a 1.5-mm slice thickness and kV-independent iterative algorithmic protocol in ULD-CT yielded excellent agreement in CAC score quantification and risk categorization compared with ECG-triggered CAC-CT.

Moving the needle: a narrative review of enhanced recovery protocols in breast reconstruction.

After a relatively late introduction to the literature in 2015, enhanced recovery protocols for breast reconstruction have flourished into a wealth of reports. Many have since described unique methodologies making improved offerings with superior outcomes attainable. This is a particularly interesting procedure for the study of enhanced recovery as it encompasses two dissident approaches. Compared to implant-based reconstruction, autologous free-flap reconstruction has demonstrated superiority in a range of long-term metrics at the expense of historically increased peri-operative morbidity. This narrative review collates reports of recovery protocols for both approaches and examines methodologies surrounding the key pieces of a comprehensive pathway. All primary clinical reports specifically describing enhanced recovery protocols for implant-based and autologous breast reconstruction through 2022 were identified by systematic review of PubMed and Embase libraries. Twenty-five reports meeting criteria were identified, with ten additional reports included for narrative purpose. Included studies were examined for facets of innovation from the pre-hospital setting through outpatient follow-up. Notable findings were described in the context of a comprehensive framework with attention paid to clinical and basic scientific background. Considerations for implementation were additionally discussed. Of 35 included studies, 29 regarded autologous reconstruction with majority focus on reduction of peri-operative opioid requirements and length of stay. Six regarded implant-based reconstruction with most discussing pathways towards ambulatory procedures. Eighty percent of included studies were published after the 2017 consensus guidelines with many described innovations to this baseline. Pathways included considerations for pre-hospital, pre-operative, intra-operative, inpatient, and outpatient settings. Implant-based studies demonstrated that safe ambulatory care is accessible. Autologous studies demonstrated a trend towards discharge before post-operative day three and peri-operative opioid requirements equivalent to those of implant-based reconstructions. Study of enhanced recovery after breast reconstruction has inspired paradigm shift and pushed limits previously not thought to be attainable. These protocols should encompass a longitudinal care pathway with optimization through patient-centered approaches and multidisciplinary collaboration. This framework should represent standard of care and will serve to expand availability of all methods of breast reconstruction.

Quantitative Amyloid‐PET in Real‐World Practice: Lessons from the Imaging Dementia—Evidence for Amyloid Scanning (IDEAS) study

AbstractBackgroundAmyloid‐PET quantification was developed in research settings using highly selected samples, harmonized acquisition protocols, and MRI‐based preprocessing. We aimed to analyze scans from IDEAS, a large‐scale, real‐world study of amyloid‐PET. Major challenges lie in scans being acquired on various PET/PET‐CT/PET‐MR scanners without standardization of acquisition or reconstruction protocols, and without MRI to preprocess data.Method18,295 Medicare beneficiaries with MCI or dementia underwent PET with [18F]florbetapir, [18F]florbetaben, or [18F]flutemetamol at 343 facilities. Sites shared 10,700 raw scans with their visual interpretation (positive or negative) by local radiologists/nuclear medicine physicians. Scans were processed using a PET‐only pipeline, which derives Centiloid based on a cortex‐to‐cerebellum tissue ratio in template space. Processed scans underwent standard visual quality control by 2 raters (Fig 1a‐b), and flagged scans were reviewed in a consensus meeting to discuss troubleshooting options. Injected dose and time between tracer injection and PET acquisition start were obtained from DICOM file header.Result9,963 scans (93%) were successfully pre‐processed with default parameters (Fig 1a) and 403 additional scans (4%) were included after manual intervention (Fig 1c). 339 scans (3%) were excluded because of technical artifacts or major bilateral lesions (Fig 1c). The final sample (n = 10,361) is described in Table 1, with example scans in Fig 1d. Centiloids showed the expected bimodal distribution (Fig 2a) and differentiated visually positive from negative scans (median = ‐2 versus 74 CL; area under the curve = 0.913, Fig 2b). PET acquisition generally followed tracer‐specific FDA recommendations for injected dose and acquisition time, but major variability was observed (Fig 2c). Centiloid values were independent from injected dose but were higher in patients scanned at later time windows for [18F]flutemetamol, resulting from known slow tracer kinetics (Fig 2c).ConclusionMRI‐free, amyloid‐PET quantification in a real‐world setting was feasible, with results conforming to expected distribution of Centiloid values and concordant with visual reads. However, greater standardization of PET acquisition than is currently required by FDA labels will be needed to reliably quantify amyloid PET in clinical practice (e.g., to monitor response to amyloid lowering therapy). The IDEAS dataset will be made available via the Global Alzheimer’s Association Interactive Network in 2023.

Impact of random and scattered coincidences from outside of field of view on positron emission tomography/computed tomography imaging with different reconstruction protocols

Impact of random and scattered coincidences from outside of field of view on positron emission tomography/computed tomography imaging with different reconstruction protocols