Reconstruction Protocols Research Articles

Difficulties of nasocutaneous fistula repair, following lacrimal outflow system malignancy resection

ABSTRACT Purpose To evaluate the incidence of nasocutaneous fistula (NCF) development, following en bloc resection of lacrimal outflow system malignancies (LOSM), and describe the methods of surgical repair. Methods Retrospective review of all patients who underwent resection of LOSM with reconstruction and post-treatment protocol at the University of Miami between 1997 and 2021. Results Of the 23 included patients, 10 (43%) developed postoperative NCF. All NCFs developed within one year of surgical resection or completion of radiation therapy. NCF was seen more frequently in patients who underwent adjuvant radiation therapy and those who had reconstruction of the orbital wall with titanium implants. All patients underwent at least one revisional surgery to close the NCF, including local flap transposition (9/10), paramedian forehead flap (5/10), pericranial flap (1/10), nasoseptal flap (2/10), and microvascular free flap (1/10). Local tissue transfer, pericranial, paramedian, and nasoseptal forehead flaps failed in most cases. Two patients had long-term closure; one patient who underwent a paramedian flap and a second who underwent a radial forearm free flap, suggesting that well-vascularized flaps may be the most viable option for repair. Conclusions NCF is a known complication, following en bloc resection of lacrimal outflow system malignancies. Risk factors for formation may include adjuvant radiation therapy and use of titanium implants for reconstruction. Surgeons should consider utilizing robust vascular-pedicled flaps or microvascular free flaps for repair of NCF in this clinical scenario.

Shame and Stigma Over Long-Term Survival in Postoperative Cases of Head and Neck Cancer.

Surgical excision of the tumor remains the primary choice for the treatment of head and neck cancer patients, but it often leads to facial disfigurement, which further causes mutilation in the patients. Mutilation causes shame and stigma, which imparts significant psychological strain on patients, and tends to impair their quality of life. The present study aimed to assess the shame and stigma over long-term postoperative survival duration in head and neck cancer patients. Total 100 postoperative patients of head and neck cancer were recruited from the outpatient department of the host institute, and shame and stigma was assessed using the Hindi version of the shame and stigma scale. The global shame and stigma score was 22.67 ± 16.22, with the highest perceived stigma due to changes in appearance (11.94 ± 8.805), followed by impaired speech (4.490 ± 3.243), feeling of regret (3.950 ± 3.313), and feeling ofstigma (4.490 ± 3.243). The shame and stigma was found to be significantly higher in maxillary cancer patients (33.22 ± 16.60), followed by larynx cancer patients(22.06 ± 13.41) and oral cancer patients(21.53 ± 16.49). Patients with stage III and stage IV of cancer were found to perceive higher shame and stigma (35.91 ± 22.23 and 27.36 ± 14.71, respectively) compared to the patients having stage I and stage II cancer (9.583 ± 9.709 and 16.44 ± 11.82, respectively). A significantly declining linear trend was found between shame and stigma and postoperative survival duration. We concluded that shame and stigma act as important determinants of quality of life over long-term survival in head and neck cancer patients,and should be considered while designing psychological interventions and surgical reconstruction protocols. The present study will help clinicians to assess the mutilation among head and neck cancer patients in a better way and will help in devising new psychological strategies to manage psychological aspects associated with mutilation, which will ultimately enhance the quality of life of patients.

Improving evaluation for TTR amyloidosis by interactive filtering of Tc-99m PYP SPECT images. The role for "clean blood pool" imaging.

Myocardial imaging with bone agents such as Tc-99m PYP and HMDP has assumed a central role in the evaluation of patients with suspected transthyretin (TTR) amyloidosis. Visual scoring (VS) (0-3 +) and the heart to contralateral lung ratio (HCL) classify many patients as equivocal when mediastinal uptake is apparent but cannot be further differentiated into myocardial uptake versus blood pool. SPECT imaging has been recommended but current reconstruction protocols frequently produce amorphous mediastinal activity that also fails to discriminate between myocardial activity and blood pool. We hypothesized that interactive filtering interactively using a deconvolving filter would improve this. We identified 176 sequential patients referred for TTR amyloid imaging. All patients had planar imaging, 101 had planar imaging with a large field of view camera that allowed HCL measurements. SPECT imaging was performed on a 3-headed digital camera with lead fluorescence attenuation correction. One study was excluded for technical reasons. We created software to allow interactive filtering while reconstructing the images then overlay them on attenuation mu maps to assist localization of myocardial/mediastinal uptake. Conventional Butterworth and an interactive inverse Gaussian filters were employed to differentiate myocardial uptake from residual blood pool. We defined "clean blood pool" (CBP) as recognizable blood pool with no activity in the surrounding myocardium. A scan was determined diagnostic if it showed CBP, positive uptake or no identifiable mediastinal uptake. 76/175 (43%) were equivocal (1 +) by visual uptake. Of these 22 (29%) were diagnostic by Butterworth but 71 (93%) were by inverse gaussian (p < .0001). 71/101 (70%) were equivocal by HCL (1-1.5). Of these, 25 (35%) were diagnostic by Butterworth but 68 (96%) were diagnostic by inverse gaussian (p < .0001). This was driven by a greater than threefold increase in the identification of CBP by inverse gaussian filtering. CBP can be identified in the vast majority of patients with equivocal PYP scans using optimized reconstruction and can greatly reduce the number of equivocal scans.

Technical Adequacy of Fully Automated Artificial Intelligence Body Composition Tools: Assessment in a Heterogeneous Sample of External CT Examinations.

BACKGROUND. Clinically usable artificial intelligence (AI) tools analyzing imaging studies should be robust to expected variations in study parameters. OBJECTIVE. The purposes of this study were to assess the technical adequacy of a set of automated AI abdominal CT body composition tools in a heterogeneous sample of external CT examinations performed outside of the authors' hospital system and to explore possible causes of tool failure. METHODS. This retrospective study included 8949 patients (4256 men, 4693 women; mean age, 55.5 ± 15.9 years) who underwent 11,699 abdominal CT examinations performed at 777 unique external institutions with 83 unique scanner models from six manufacturers with images subsequently transferred to the local PACS for clinical purposes. Three independent automated AI tools were deployed to assess body composition (bone attenuation, amount and attenuation of muscle, amount of visceral and sub-cutaneous fat). One axial series per examination was evaluated. Technical adequacy was defined as tool output values within empirically derived reference ranges. Failures (i.e., tool output outside of reference range) were reviewed to identify possible causes. RESULTS. All three tools were technically adequate in 11,431 of 11,699 (97.7%) examinations. At least one tool failed in 268 (2.3%) of the examinations. Individual adequacy rates were 97.8% for the bone tool, 99.1% for the muscle tool, and 98.9% for the fat tool. A single type of image processing error (anisometry error, due to incorrect DICOM header voxel dimension information) accounted for 81 of 92 (88.0%) examinations in which all three tools failed, and all three tools failed whenever this error occurred. Anisometry error was the most common specific cause of failure of all tools (bone, 31.6%; muscle, 81.0%; fat, 62.8%). A total of 79 of 81 (97.5%) anisometry errors occurred on scanners from a single manufacturer; 80 of 81 (98.8%) occurred on the same scanner model. No cause of failure was identified for 59.4% of failures of the bone tool, 16.0% of failures of the muscle tool, or 34.9% of failures of the fat tool. CONCLUSION. The automated AI body composition tools had high technical adequacy rates in a heterogeneous sample of external CT examinations, supporting the generalizability of the tools and their potential for broad use. CLINICAL IMPACT. Certain causes of AI tool failure related to technical factors may be largely preventable through use of proper acquisition and reconstruction protocols.

Functional outcomes of a criterion-based rehabilitation protocol for anterior cruciate ligament reconstruction in amateur athletes: A randomised clinical trial

IntroductionAlthough current rehabilitation protocols following anterior cruciate ligament reconstruction (ACLR) are based on the graft remodeling process, there is uncertainty about its time schedule. Moreover, there are individual differences in neuromotor learning and flexibility after ACLR. The current study was conducted to investigate the functional outcomes of the criterion-based rehabilitation protocol in amateur athletes following ACLR. MethodsFifty amateur male athletes who had ACLR were assigned randomly into two equal groups. The experimental group received a criterion-based rehabilitation protocol. The control group received a conventional physical therapy program. Both groups had five treatment sessions per week for six months. The primary outcome was pain intensity measured by VAS. Secondary outcomes included functional assessments measured by the limb symmetry index (LSI) of the hop test battery, knee effusion, and the Knee injury and Osteoarthritis Outcome Score (KOOS). ResultsMixed-design-MANOVA indicated significant treatment, time, and treatment × time interaction. The interaction was significant for all outcome measures in favor of subjects who received a criterion-based rehabilitation protocol. Within-group analysis revealed a significant reduction in pain in both groups and improvements in all variables related to the KOOS or LSI of the hop test battery. Knee effusion was significantly reduced post-treatment in patients who received a criterion-based protocol when compared to their controls. ConclusionsAlthough application of a criterion-based rehabilitation protocol for 6 months after ACLR is more effective than a conventional program, its duration should be expanded beyond this period to allow patients to reach their return to play goals.

PHANTOM AND CLINICAL STUDIES ON LOW-DOSE CT PROTOCOL FOR APPLICATOR RECONSTRUCTION IN THREE-DIMENSIONAL BRACHYTHERAPY USING SIZE-SPECIFIC DOSE ESTIMATES BASED ON WATER EQUIVALENT DIAMETER.

To verify the feasibility of low-dose computed tomography (CT) protocol for applicator reconstruction in three-dimensional brachytherapy among patients of different sizes, using size-specific dose estimate based on water equivalent diameter (SSDEdw) in phantom and clinical studies. Pre-scans of a female pelvic phantom were followed by reconstruction of each image set with iDose4 levels 3-5. Imaging data from 64 cervical cancer patients were divided into low, standard and high weight groups. Among two to five CT scans required for applicator reconstruction, the first scan was adopted by routine-dose CT protocol (tube voltage = 120 kV, tube current-exposure time product = 320 mA.s) and the remaining by low-dose CT protocol (tube voltage = 120 kV, tube current-exposure time product = 80 mA.s). The SSDEdw and image quality parameters were compared among the groups, and correlations between SSDEdw and body mass index, area of reference plane (AreaROI3) and mean CT value of reference plane (CTROI3) were analyzed. According to the phantom test results, we determined tube voltage to 120 kV and tube current-exposure time product to 80 mA.s as the low-dose protocol. Clinical study revealed no statistically significant differences in signal-to-noise ratio (SNR) and contrast-noise-ratio (CNR) between low-dose and routine-dose CT in Groups A and B; in Group C, these were significantly lower in the former. The SSDEdw was significantly lower under low-dose than routine-dose protocol in all groups, with strong negative correlation with BMI and AreaROI3 in Groups A and B and moderate-to-strong negative correlation in Group C. Because of the characteristics of three-dimensional brachytherapy, in patients with BMI < 24.0 kg per m2, low-dose CT protocol can minimize radiation exposure and achieve precise, individualized treatment.

Deep Learning CT Image Restoration using System Blur Models.

Restoration of images contaminated by blur is an important processing tool across modalities including computed tomography where the blur induced by various system factors can be complex with dependencies on acquisition and reconstruction protocol, and even be patient-dependent. In many cases, such a blur can be modeled and predicted with high accuracy providing an important input to a classical deconvolution approach. While traditional deblurring methods tend to be highly noise magnifying, deep learning approaches have the potential to improve upon classic performance limits. However, most network architectures base their restoration on data inputs alone without knowledge of the system blur. In this work, we explore a deep learning approach that takes both image inputs as well as information that characterizes the system blur to combine modeling and deep learning approaches. We apply the approach to CT image restoration and compare with an image-only deep learning approach. We find that inclusion of the system blur model improves deblurring performance - suggesting the potential power of the combined modeling and deep learning technique.

Multicenter quantitative 18F-fluorodeoxyglucose positron emission tomography performance harmonization: use of hottest voxels towards more robust quantification.

Harmonization methods reduce variability between different make and models of positron emission tomography (PET) scanners. The study aims to explore harmonization strategies that lead to comparable and robust quantitative metrics in a multicenter setting. NEMA IEC Phantom data acquisition was performed for low and high spheres-to-background ratios (SBR4:1 and 10:1) on six PET/CT (computed tomography) scanners. Different reconstruction sets, including the number of sub-iterations, number of subsets, and full width at half maximum (FWHM) for each scanner, were evaluated towards optimized and harmonized reconstruction settings. Recovery coefficients (RCs) of four quantitative metrics, including standardized uptake value (SUV)max, SUVISO-50 (SUVmean in 50% isocontour), SUVpeak, and mean uptake of 10 highest concentration voxels were evaluated as RCmax, RCISO-50, RCpeak, and RC10V, representing percent difference relative to the static ground truth case as functions of sphere sizes. A set of image reconstruction parameters was proposed for harmonized reconstruction to minimize variability between scanners. The root mean square error (RMSE), curvature, and reproducibility were examined. The proposed reconstruction protocols for harmonization and standard clinical reconstruction settings were compared to each other across all scanners. A significant difference (P value <0.0001) was observed in the aforementioned quantitative metrics between SBR10 and SBR4. Reconstruction parameter sets with the smallest RMSE and RC values within 10% bias were identified as the best candidate for harmonization. The coefficient of variation of the mean value of RCs (CVMRC) shows a remarkable reduction of about 28%, 26%, 32%, and 19% in harmonized reconstruction settings for MRCmax, MRCISO-50, MRCpeak, and MRC10V, respectively. CVMRC for MRC10V in the harmonized reconstruction setting was 5.9% in SBR4, while the smallest value in SBR10 belongs to MRCpeak, with a value of 5.8%. The reproducibility of RC is improved by deriving the value from ten hottest voxels and is equally reproducible with RCpeak. Compared to RCmax and RCISO-50, the variability is reduced by 18% and 22% if ten voxels are pooled. Harmonizing PET/CT systems with and without point spread function/time of flight (PSF/TOF) using various vendor-developed image reconstruction algorithms improves the quantification reproducibility. RC10V, likewise RCpeak, is superior to the rest of the quantitative indices in terms of accuracy and reproducibility and helpful in quantifying lesion volume below 1 mL.

Same same but different: dopamine transporter SPECT on scanners with CZT vs. NaI detectors

BackgroundThe aims of this study were to establish a normal database (NDB) for semiquantification of dopamine transporter (DAT) single-photon emission computed tomography (SPECT) with [123I]FP-CIT on a cadmium zinc telluride (CZT) camera, test the preexisting NaI-derived NDB for use in CZT scans, and compare the diagnostic findings in subjects imaged with a CZT scanner with either the preexisting NaI-based NDB or our newly defined CZT NDB.MethodsThe sample comprised 73 subjects with clinically uncertain parkinsonian syndrome (PS) who prospectively underwent [123I]FP-CIT SPECT on a CZT camera according to standard guidelines with identical acquisition and reconstruction protocols (DaTQUANT). Two experienced readers visually assessed the images and binarized the subjects into “non-neurodegenerative PS” and “neurodegenerative PS”. Twenty-five subjects from the “non-neurodegenerative PS” subgroup were randomly selected to establish a CZT NDB. The remaining 48 subjects were defined as “test group”. DaTQUANT was used to determine the specific binding ratio (SBR). For the test group, SBR values were transformed to z-scores for the putamen utilizing both the CZT NDB and the manufacturer-provided NaI-based NDB (GE NDB). A predefined fixed cut-off of -2 was used for dichotomization of z-scores to classify neurodegenerative and non-neurodegenerative PS. Performance of semiquantification using the two NDB to identify subjects with neurodegenerative PS was assessed in comparison with the visual rating. Furthermore, a randomized head-to-head comparison of both detector systems was performed semiquantitatively in a subset of 32 out of all 73 subjects.ResultsCompared to the visual rating as reference, semiquantification based on the dedicated CZT NDB led to fewer discordant ratings than the GE NDB in CZT scans (3 vs. 8 out of 48 subjects). This can be attributed to the putaminal z-scores being consistently higher with the GE NDB on a CZT camera (median absolute difference of 1.68), suggesting an optimal cut-off of -0.5 for the GE NDB instead of -2.0. Average binding ratios and z-scores were significantly lower in CZT compared to NaI data.ConclusionsUse of a dedicated, CZT-derived NDB is recommended in [123I]FP-CIT SPECT with a CZT camera since it improves agreement between semiquantification and visual assessment.

Optimisation of scan duration and image quality in oncological 89Zr immunoPET imaging using the Biograph Vision PET/CT

PurposeMonoclonal antibody (mAb)-based PET (immunoPET) imaging can characterise tumour lesions non-invasively. It may be a valuable tool to determine which patients may benefit from treatment with a specific monoclonal antibody (mAb) and evaluate treatment response. For 89Zr immunoPET imaging, higher sensitivity of state-of-the art PET/CT systems equipped with silicon photomultiplier (SiPM)-based detector elements may be beneficial as the low positron abundance of 89Zr causes a low signal-to-noise level. Moreover, the long physical half-life limits the amount of activity that can be administered to the patients leading to poor image quality even when using long scan durations. Here, we investigated the difference in semiquantitative performance between the PMT-based Biograph mCT, our clinical reference system, and the SiPM-based Biograph Vision PET/CT in 89Zr immunoPET imaging. Furthermore, the effects of scan duration reduction using the Vision on semiquantitative imaging parameters and its influence on image quality assessment were evaluated.MethodsData were acquired on day 4 post 37 MBq 89Zr-labelled mAb injection. Five patients underwent a double scan protocol on both systems. Ten patients were scanned only on the Vision. For PET image reconstruction, three protocols were used, i.e. one camera-dependent protocol and European Association of Nuclear Medicine Research Limited (EARL) standards 1 and 2 compliant protocols. Vision data were acquired in listmode and were reprocessed to obtain images at shorter scan durations. Semiquantitative PET image parameters were derived from tumour lesions and healthy tissues to assess differences between systems and scan durations. Differently reconstructed images obtained using the Vision were visually scored regarding image quality by two nuclear medicine physicians.ResultsWhen images were reconstructed using 100% acquisition time on both systems following EARL standard 1 compliant reconstruction protocols, results regarding semiquantification were comparable. For Vision data, reconstructed images that conform to EARL1 standards still resulted in comparable semiquantification at shorter scan durations (75% and 50%) regarding 100% acquisition time.ConclusionScan duration of 89Zr immunoPET imaging using the Vision can be decreased up to 50% compared with using the mCT while maintaining image quality using the EARL1 compliant reconstruction protocol.

Breast Reconstruction Trends in the Setting of Postmastectomy Radiation Therapy: Analysis of Practices among Plastic Surgeons in the United States.

A cross-sectional survey of members of the American Society of Plastic Surgery was performed. Practice/demographic information and breast reconstruction protocols were queried. Univariate descriptive statistics were calculated, and outcomes were compared across cohorts with χ2 and Fischer exact tests. Overall, 477 plastic surgeons averaging 16.3 years in practice were surveyed. With respect to types of reconstruction, all options were well represented, although nearly 60% preferred autologous reconstruction with prior radiation and 55% preferred tissue expansion followed by implant/autologous reconstruction in the setting of unknown postoperative radiation. There was little consensus on the optimal timing of reconstruction in the setting of possible postoperative radiation. Most respondents wait 4-6 or 7-12 months between the end of radiation and stage 2 implant-based or autologous reconstruction. Common concerns regarding the effect of radiation on reconstructive outcomes included mastectomy flap necrosis, wound dehiscence, capsular contracture, tissue fibrosis, and donor vessel complications. Despite considerable research, there is little consensus on the ideal type and timing of reconstruction in the setting of pre- and postoperative radiation. Understanding how the current body of knowledge is translated into clinical practice by different populations of surgeons allows us to forge a path forward toward more robust, evidence-based guidelines for patient care.

Role of Lesion-to-Background Activity Ratio and Background Activity in Optimization of Reconstruction Protocols for FDG PET/CT Images of Overweight Patients: A Phantom Study

Background: The quality of positron emission tomography/computed tomography (PET/CT) images plays an important role in tumor detection. This imaging method often yields poor-quality images of overweight patients due to the high level of noise, originating from scattering and photon attenuation. Objectives: The point spread function (PSF) is mostly used to enhance the spatial resolution and signal-to-noise ratio (SNR); however, it is known to increase the edge artifacts. The time-of-flight (TOF) principle can reduce edge artifacts in PSF modeling and improve lesion detection, especially in the thorax. The present study aimed to assess these two new techniques by applying different reconstruction parameters. Materials and Methods: An in-house phantom with an inner diameter of 35 cm was used for the simulation of overweight patients. Lesion-to-background ratios (LBRs) of 2: 1 and 8: 1, as well as background activity concentrations of 3 and 5 kBq/cc, were considered in this study. The list-mode data were reconstructed with various reconstruction protocols, numbers of subsets, and filter sizes. Quantitative analyses, including the coefficient of variation (COV), SNR, and recovery coefficient (RC), were also carried out. Moreover, box-and-whisker plots were performed. Results: At LBR of 2: 1, by changing the protocol from ordered subset expectation maximization (OSEM) to OSEM + PSF + TOF, the median value of SNR for 13-mm lesions (37 mm) increased by 39.25% and 53.45% (42.22% and 56.21%), at background activity concentrations of 3 and 5 kBq/cc respectively. However, at LBR of 8: 1, the corresponding values were 33.22% and 48.94% (40.22% and 52.15%) at background activity concentrations of 3 and 5 kBq/cc respectively. Conclusion: The TOF protocols were strongly recommended for both background activity concentrations at LBR of 2: 1 and for the low background activity concentration at LBR of 8: 1, especially when using smaller filter sizes. Moreover, subset numbers of 18 and 24 were appropriate for all protocols. However, a smaller subset number was suitable when a low background activity concentration and a smaller filter size were applied, especially at a lower LBR.

Role of Lesion-to-Background Activity Ratio and Background Activity in Optimization of Reconstruction Protocols for FDG PET/CT Images of Overweight Patients: A Phantom Study

Background: The quality of positron emission tomography/computed tomography (PET/CT) images plays an important role in tumor detection. This imaging method often yields poor-quality images of overweight patients due to the high level of noise, originating from scattering and photon attenuation. Objectives: The point spread function (PSF) is mostly used to enhance the spatial resolution and signal-to-noise ratio (SNR); however, it is known to increase the edge artifacts. The time-of-flight (TOF) principle can reduce edge artifacts in PSF modeling and improve lesion detection, especially in the thorax. The present study aimed to assess these two new techniques by applying different reconstruction parameters. Materials and Methods: An in-house phantom with an inner diameter of 35 cm was used for the simulation of overweight patients. Lesion-to-background ratios (LBRs) of 2: 1 and 8: 1, as well as background activity concentrations of 3 and 5 kBq/cc, were considered in this study. The list-mode data were reconstructed with various reconstruction protocols, numbers of subsets, and filter sizes. Quantitative analyses, including the coefficient of variation (COV), SNR, and recovery coefficient (RC), were also carried out. Moreover, box-and-whisker plots were performed. Results: At LBR of 2: 1, by changing the protocol from ordered subset expectation maximization (OSEM) to OSEM + PSF + TOF, the median value of SNR for 13-mm lesions (37 mm) increased by 39.25% and 53.45% (42.22% and 56.21%), at background activity concentrations of 3 and 5 kBq/cc respectively. However, at LBR of 8: 1, the corresponding values were 33.22% and 48.94% (40.22% and 52.15%) at background activity concentrations of 3 and 5 kBq/cc respectively. Conclusion: The TOF protocols were strongly recommended for both background activity concentrations at LBR of 2: 1 and for the low background activity concentration at LBR of 8: 1, especially when using smaller filter sizes. Moreover, subset numbers of 18 and 24 were appropriate for all protocols. However, a smaller subset number was suitable when a low background activity concentration and a smaller filter size were applied, especially at a lower LBR.

МЕТОДИКА ЭКСПЕРТНОЙ ОЦЕНКИ КАЧЕСТВА ПЭТ-ИЗОБРАЖЕНИЙ ПАЦИЕНТОВ

Purpose: To develop the method of experts’ quality evaluation of the PET images as an additional quality control method for accurate, comparable, and reproducible PET diagnostics results, and to conduct image quality evaluation in different PET departments used this method. Material and methods: 60 PET images (without CT) of the patients who underwent whole body PET/CT with 18F-FDG were collected from 12 PET/CT scanners in 9 PET departments. Experts’ quality evaluation was conducted with questioning of the experts. Each expert evaluated the image quality by five-point scale and filled out the special form which include three image quality criteria: image clarity, artefacts, and general image quality. There were 28 experts from 8 different PET departments who have work experience in radiology from 1 to 32 years. The results of experts’ quality evaluation of the PET images were examined for correlations with parameters of acquisition and reconstruction protocols, examination methods. The results were also examined for dependance of subjective factors such as work experience and work conditions of experts. The minimum required number of experts were defined. The results were analyzed used statistical methods. Results: The PET images obtained by 8 PET/CT scanners had mean quality value more than 4 points (good quality). PET/CT scanners, which had the lowest quality value, have the obsolete or unusual settings and reconstruction parameters. The correlations between experts’ quality evaluation of the PET images and acquisition parameters (acquisition time per bed, multiplication of injected activity and acquisition time per bed), and examination methods (injected activity and uptake time) were established. The results of experts’ quality evaluation of the PET images were dependent on work experience and work conditions of experts. Conclusion: The method of experts’ quality evaluation of the PET images of the patients based on the questioning of the experts working in PET was developed and demonstrated in the current study. The results showed this method has the potential to compare the PET images obtained by different acquisition and reconstruction protocols, and it can be applied during the optimization of examination method and for the determination of obsolete and unusual settings of PET/CT. Experts’ evaluation of the PET images should include the opinion of at least six experts with different work experience in PET from several PET departments.

Ballistic Facial Trauma Reconstruction: Incidence and Practice Patterns in the Civilian Population.

Management of nonfatal ballistic facial trauma is well described in the literature for wounds secondary to military combat. However, there is little literature describing such management in civilian practice. We aimed to describe nonmilitary patients with recent nonfatal facial injuries from ballistic trauma using the California Office of Statewide Health Planning and Development patient database. A retrospective study was performed using the California Office of Statewide Health Planning and Development Ambulatory Surgery and Inpatient datasets. All adults with the International Classification of Diseases, 10th Revision codes of severe nonfatal facial trauma from firearms requiring emergent surgery during 2016-2018 were included. Outcomes assessed include number and type of facial procedures performed, hospital length of stay, number of admissions, timing of definitive management, and lifetime hospitalization costs. A total of 331 traceable patients were identified over this 3-year period. The average age was 35.4 years (SD, 15.2), and 87% were male. The median index admission length of stay was 8 days (interquartile range, 3-15 days). Subsequent readmission was required for 123 (37.2%) patients with 10% mortality in the index admission. Total median charges per patient for all admissions were $257,804 (interquartile range, $105,601-$531,916). A total of 215 patients (65%) had at least 1 facial repair performed. Of all 331 patients, 64.3% underwent musculoskeletal repair (n = 213), 31.4% underwent digestive system repair (n = 104), and 29.6% underwent respiratory system repair (n = 98). The average number of repairs per patient was 2.52 (SD, 3.38), with 35% not having any of the specified International Classification of Diseases, 10th Revision repair codes. A total of 27% of patients had 1 procedure performed, whereas 38% received 2 or more, for an average of 3.87 (SD, 3.5) repairs over the study duration. To our knowledge, this is the first assessment of civilian characteristics of nonfatal ballistic facial trauma in California. Nonfatal facial ballistic trauma results in complex injuries to multiple body systems, requiring long admissions, costly hospital stays, and coordination of care across several surgical specialties. Many patients require a variety of procedures over multiple admissions, highlighting the overall morbidity of these injuries. Future studies will look at how care for these patients differs between various hospitals and geographic regions and whether current civilian management aligns with well-defined military reconstructive protocols for facial ballistic injuries.

Reproducibility of the computational fluid dynamic analysis of a cerebral aneurysm monitored over a decade

Computational fluid dynamics (CFD) simulations are increasingly utilised to evaluate intracranial aneurysm (IA) haemodynamics to aid in the prediction of morphological changes and rupture risk. However, these models vary and differences in published results warrant the investigation of IA-CFD reproducibility. This study aims to explore sources of intra-team variability and determine its impact on the aneurysm morphology and CFD parameters. A team of four operators were given six sets of magnetic resonance angiography data spanning a decade from one patient with a middle cerebral aneurysm. All operators were given the same protocol and software for model reconstruction and numerical analysis. The morphology and haemodynamics of the operator models were then compared. The segmentation, smoothing factor, inlet and outflow branch lengths were found to cause intra-team variability. There was 80% reproducibility in the time-averaged wall shear stress distribution among operators with the major difference attributed to the level of smoothing. Based on these findings, it was concluded that the clinical applicability of CFD simulations may be feasible if a standardised segmentation protocol is developed. Moreover, when analysing the aneurysm shape change over a decade, it was noted that the co-existence of positive and negative values of the wall shear stress divergence (WSSD) contributed to the growth of a daughter sac.

ANTEROMEDIAL OR CENTRAL ANATOMIC ACL RECONSTRUCTION? A CADAVERIC HIP-TO-TOE STUDY.

To compare anatomic anterior cruciate ligament (ACL) reconstruction between two tunnel positions in knees with isolated ligament tears. Anatomic ACL reconstruction was performed, from hip-to-toe, on 15 fresh cadaveric specimens. No associated lesions were created to enhance knee instability. The protocol was conducted in three states: (1) complete isolated ACL deficiency; (2) anatomic femoral and tibial anteromedial ACL reconstruction (AM REC); and (3) anatomic femoral and tibial central ACL reconstruction (Central REC). The reconstruction protocols were randomly assigned. The continuous mechanized pivot-shift test was recorded dynamically with a tracking system. The Central REC group showed a smaller degree of internal rotation (0.6° ± 0.3° vs. 1.8° ± 0.3°, respectively, P < 0.05) and no difference in anterior translation (4.7 mm ± 0.4 mm vs. 4.5 mm ± 0.4 mm, respectively, P > 0.05) in the pivot-shift test, compared with the AM REC group. The central anatomic ACL reconstruction resulted in greater restriction of internal rotation than the anteromedial anatomic ACL reconstruction. Experimental Study on Cadaver.

The lapidary elements of the Castle of Belvoir

The systematic study of the blocks of the Belvoir castle lapidary has allowed us to restore several architectural ensembles that could have belonged to the castle chapel, which has now disappeared. In this article, we present the method of analysis and recording of these blocks, as well as the protocol of 3D reconstruction that allowed us to formulate several hypotheses concerning the shape, decoration and roof of the chapel. One of them proposes an architectural ensemble with an ogival vault, to which numerous lapidary elements seem to belong, but in opposition to the style of contemporary constructions in the Latin East. As for the other, it is based on a style more in line with the architectural context, but few of the stones found could belong to it. Without proposing to definitively settle the question, this article also demonstrates the interest of a very strong interconnection between archaeologists, stone-cutting specialists and architects allowing, around the 3D reconstruction, to propose hypotheses considering all the data of the problem.

Nanoscale covariance magnetometry with diamond quantum sensors

Nitrogen vacancy (NV) centers in diamond are atom-scale defects that can be used to sense magnetic fields with high sensitivity and spatial resolution. Typically, the magnetic field is measured by averaging sequential measurements of single NV centers, or by spatial averaging over ensembles of many NV centers, which provides mean values that contain no nonlocal information about the relationship between two points separated in space or time. Here, we propose and implement a sensing modality whereby two or more NV centers are measured simultaneously, and we extract temporal and spatial correlations in their signals that would otherwise be inaccessible. We demonstrate measurements of correlated applied noise using spin-to-charge readout of two NV centers and implement a spectral reconstruction protocol for disentangling local and nonlocal noise sources.

Decentralized collaborative multi-institutional PET attenuation and scatter correction using federated deep learning

PurposeAttenuation correction and scatter compensation (AC/SC) are two main steps toward quantitative PET imaging, which remain challenging in PET-only and PET/MRI systems. These can be effectively tackled via deep learning (DL) methods. However, trustworthy, and generalizable DL models commonly require well-curated, heterogeneous, and large datasets from multiple clinical centers. At the same time, owing to legal/ethical issues and privacy concerns, forming a large collective, centralized dataset poses significant challenges. In this work, we aimed to develop a DL-based model in a multicenter setting without direct sharing of data using federated learning (FL) for AC/SC of PET images.MethodsNon-attenuation/scatter corrected and CT-based attenuation/scatter corrected (CT-ASC) 18F-FDG PET images of 300 patients were enrolled in this study. The dataset consisted of 6 different centers, each with 50 patients, with scanner, image acquisition, and reconstruction protocols varying across the centers. CT-based ASC PET images served as the standard reference. All images were reviewed to include high-quality and artifact-free PET images. Both corrected and uncorrected PET images were converted to standardized uptake values (SUVs). We used a modified nested U-Net utilizing residual U-block in a U-shape architecture. We evaluated two FL models, namely sequential (FL-SQ) and parallel (FL-PL) and compared their performance with the baseline centralized (CZ) learning model wherein the data were pooled to one server, as well as center-based (CB) models where for each center the model was built and evaluated separately. Data from each center were divided to contribute to training (30 patients), validation (10 patients), and test sets (10 patients). Final evaluations and reports were performed on 60 patients (10 patients from each center).ResultsIn terms of percent SUV absolute relative error (ARE%), both FL-SQ (CI:12.21–14.81%) and FL-PL (CI:11.82–13.84%) models demonstrated excellent agreement with the centralized framework (CI:10.32–12.00%), while FL-based algorithms improved model performance by over 11% compared to CB training strategy (CI: 22.34–26.10%). Furthermore, the Mann–Whitney test between different strategies revealed no significant differences between CZ and FL-based algorithms (p-value > 0.05) in center-categorized mode. At the same time, a significant difference was observed between the different training approaches on the overall dataset (p-value < 0.05). In addition, voxel-wise comparison, with respect to reference CT-ASC, exhibited similar performance for images predicted by CZ (R2 = 0.94), FL-SQ (R2 = 0.93), and FL-PL (R2 = 0.92), while CB model achieved a far lower coefficient of determination (R2 = 0.74). Despite the strong correlations between CZ and FL-based methods compared to reference CT-ASC, a slight underestimation of predicted voxel values was observed.ConclusionDeep learning-based models provide promising results toward quantitative PET image reconstruction. Specifically, we developed two FL models and compared their performance with center-based and centralized models. The proposed FL-based models achieved higher performance compared to center-based models, comparable with centralized models. Our work provided strong empirical evidence that the FL framework can fully benefit from the generalizability and robustness of DL models used for AC/SC in PET, while obviating the need for the direct sharing of datasets between clinical imaging centers.