Resolution Scanning Research Articles

Super-Resolution in Clinically Available Spinal Cord MRIs Enables Automated Atrophy Analysis.

Measurement of the mean upper cervical cord area (MUCCA) is an important biomarker in the study of neurodegeneration. However, dedicated high-resolution scans of the cervical spinal cord are rare in standard-of-care imaging due to timing and clinical usability. Most clinical cervical spinal cord imaging is sagittally acquired in 2D with thick slices and anisotropic voxels. As a solution, previous work describes high-resolution T1-weighted brain imaging for measuring the upper cord area, but this is still not common in clinical care. We propose using a zero-shot super-resolution technique, SMORE, already validated in the brain, to enhance the resolution of 2D-acquired scans for upper cord area calculations. To incorporate super-resolution in spinal cord analysis, we validate SMORE against high-resolution research imaging and in a real-world longitudinal data analysis. Super-resolved images reconstructed using SMORE showed significantly greater similarity to the ground truth than low-resolution images across all tested resolutions (p<0.001 for all resolutions in PSNR and MSSIM). MUCCA results from super-resolved scans demonstrate excellent correlation with high-resolution scans (r>0.973 for all resolutions) compared to low-resolution scans. Additionally, super-resolved scans are consistent between resolutions (r>0.969), an essential factor in longitudinal analysis. Compared to clinical outcomes such as walking speed or disease severity, MUCCA values from low-resolution scans have significantly lower correlations than those from high-resolution scans. Super-resolved results have no significant difference. In a longitudinal real-world dataset, we show that these super-resolved volumes can be used in conjunction with T1-weighted brain scans to show a significant rate of atrophy (-0.790, p=0.020 vs. -0.438, p=0.301 with low-resolution). Super-resolution is a valuable tool for enabling large-scale studies of cord atrophy, as low-resolution images acquired in clinical practice are common and available. MS=multiple sclerosis; MUCCA=mean upper cervical cord; HR=high-resolution; LR=low-resolution; SR=superresolved; CSC=cervical spinal cord; PMJ=pontomedullary junction; MSSIM=mean structural similarity; PSNR=peak signal-to-noise ratio; EDSS=expanded disability status scale.

A novel methodology for analysing dental implant positional changes from virtual planning to placement without CBCT.

Introduction This paper introduces a novel methodology for analysing dental implant positioning in vivo, advancing beyond traditional methods that rely on post-placement cone beam computed tomography (CBCT) scans.Method The core of the methodology is comparing stereolithography (STL) files, representing pre-planned and actual post-placement implant positions. These STL files, exported from guided surgery planning and computer-aided design software, focus on clinically significant key points, like the apical and coronal midpoints. Additionally, the method uses pose detection, differing fundamentally from CBCT scan approximations.Discussion Relying on pose detection instead of scanner resolution, this method aligns with international standards and overcomes CBCT and intra-oral scanner limitations. It allows for a more precise and accurate assessment of implant positions, independent of scanner technology constraints. Further refinements include potential detailed reporting of apical deviations, enhancing implant placement accuracy.Conclusion This research has significant implications for dental implantology, enhancing implant placement precision and overall procedure success. Introducing an automated process for report generation through a batch script improves efficiency and precision, streamlining the analysis process. This innovation sets the stage for future technological advancements, improving both the accuracy and reliability of implant placement assessments.

Cooperation between Coagulase and von Willebrand factor binding protein in Staphylococcus aureus fibrin pseudocapsule formation

The major human pathogen Staphylococcus aureus forms biofilms comprising of a fibrin network that increases attachment to surfaces and shields bacteria from the immune system. It secretes two coagulases, Coagulase (Coa) and von Willebrand factor binding protein (vWbp), which hijack the host coagulation cascade and trigger the formation of this fibrin clot. However, it is unclear how Coa and vWbp contribute differently to the localisation and dynamics of clot assembly in growing biofilms.Here, we address this question using high-precision time-resolved confocal microscopy of fluorescent fibrin to establish the spatiotemporal dynamics of fibrin clot formation in functional biofilms. We also use fluorescent fusion proteins to visualise the locations of Coa and vWbp in biofilms using both confocal laser scanning and high resolution highly inclined and laminated optical sheet microscopy. We visualise and quantify the spatiotemporal dynamics of fibrin production during initiation of biofilms in plasma amended with fluorescently labelled fibrinogen.We find that human serum stimulates coagulase production, and that Coa and vWbp loosely associate to the bacterial cell surface. Coa localises to cell surfaces to produce a surface-attached fibrin pseudocapsule but can diffuse from cells to produce matrix-associated fibrin. vWbp produces matrix-associated fibrin in the absence of Coa, and furthermore accelerates pseudocapsule production when Coa is present. Finally, we observe that fibrin production varies across the biofilm. A sub-population of non-dividing cells does not produce any pseudocapsule but remains within the protective extended fibrin network, which could be important for the persistence of S. aureus biofilm infections as antibiotics are more effective against actively growing cells.Our findings indicate a more cooperative role between Coa and vWbp in building fibrin networks than previously thought, and a bet-hedging cell strategy where some cells produce biofilm matrix while others do not, but instead assume a dormant phenotype that could be associated with antibiotic tolerance.

On the accuracy of the segmentation process and transcatheter heart valve dimensions in TAVI patients

Accurate segmentation of medical images is critical for generating patient-specific models suitable for computational analyses, particularly in the context of transcatheter aortic valve implantation (TAVI). This study aimed to quantify the accuracy of the segmentation process from medical images of TAVI patients to understand the uncertainty in patient-specific geometries. We also quantified discrepancies between actual and CT-related diameter measurements due to artifacts and intra-observer variability. Segmentation accuracy was assessed using both synthetic phantom models and patient-specific data. The impact of voxelization and CT scanner resolution on segmentation accuracy was evaluated, while the intersection over union (IoU) metric was used to compare the consistency of different segmentation methodologies. The voxelization process introduced a marginal error (<1%) in phantom models relative to CAD models. CT scanner resolution impacted segmented model accuracy only after a 7.5-fold increase in voxel size compared to the baseline medical image. IoU analysis revealed higher segmentation accuracy for calcification (93.4 ± 3.1 %) compared to the aortic wall (85.4 ± 8.4 %) and native valve leaflets (75.5 ± 6.3 %). Discrepancies in THV diameter measurements highlighted a ∼5 % error due to metallic artifacts, with variability among observers and at different THV heights. Errors due to voxel size, segmentation methodologies and CT-related artifacts can impact the reliability of patient-specific geometries and ultimately computational predictions used to asses clinical outcomes and enhance decision-making. This study underscores the importance of accurate segmentation and its standardization for patient-specific modeling of TAVI simulations.

Multimodal Data-Driven Segmentation of Bone Metastasis Lesions in SPECT Bone Scans Using Deep Learning

Background: Patients with malignant tumors often develop bone metastases. SPECT bone scintigraphy is an effective tool for surveying bone metastases due to its high sensitivity, low-cost equipment, and radiopharmaceutical. However, the low spatial resolution of SPECT scans significantly hinders manual analysis by nuclear medicine physicians. Deep learning, a promising technique for automated image analysis, can extract hierarchal patterns from images without human intervention. Objective: To enhance the performance of deep learning-based segmentation models, we integrate textual data from diagnostic reports with SPECT bone scans, aiming to develop an automated analysis method that outperforms purely unimodal data-driven segmentation models. Methods: We propose a dual-path segmentation framework to extract features from bone scan images and diagnostic reports separately. In the first path, an encoder-decoder network is employed to learn hierarchical representations of features from SPECT bone scan images. In the second path, the Chinese version of the MacBERT model is utilized to develop a text encoder for extracting features from diagnostic reports. The extracted textual features are then fused with image features during the decoding stage in the first path, enhancing the overall segmentation performance. Results: Experimental evaluation conducted on real-world clinical data demonstrated the superior performance of the proposed segmentation model. Our model achieved a 0.0209 increase in the DSC (Dice Similarity Coefficient) score compared to the well-known U-Net model. Conclusions: The proposed multimodal data-driven method effectively identifies and isolates metastasis lesions in SPECT bone scans, outperforming existing classical deep learning models. This study demonstrates the value of incorporating textual data in the deep learning-based segmentation of lowresolution SPECT bone scans.

On the implementation of acollinearity in PET Monte Carlo simulations

Objective.Acollinearity of annihilation photons (APA) introduces spatial blur in positron emission tomography (PET) imaging. This phenomenon increases proportionally with the scanner diameter and it has been shown to follow a Gaussian distribution. This last statement can be interpreted in two ways: the magnitude of the acollinearity angle, or the angular deviation of annihilation photons from perfect collinearity. As the former constitutes the partial integral of the latter, a misinterpretation could have significant consequences on the resulting spatial blurring. Previous research investigating the impact of APA in PET imaging has assumed the Gaussian nature of its angular deviation, which is consistent with experimental results. However, a comprehensive analysis of several simulation software packages for PET data acquisition revealed that the magnitude of APA was implemented as a Gaussian distribution.Approach.We quantified the impact of this misinterpretation of APA by comparing simulations obtained with GATE, which is one of these simulation programs, to an in-house modification of GATE that models APA deviation as following a Gaussian distribution.Main results.We show that the APA misinterpretation not only alters the spatial blurring profile in image space, but also considerably underestimates the impact of APA on spatial resolution. For an ideal PET scanner with a diameter of 81 cm, the APA point source response simulated under the first interpretation has a cusp shape with 0.4 mm FWHM. This is significantly different from the expected Gaussian point source response of 2.1 mm FWHM reproduced under the second interpretation.Significance.Although this misinterpretation has been found in several PET simulation tools, it has had a limited impact on the simulated spatial resolution of current PET scanners due to its small magnitude relative to the other factors. However, the inaccuracy it introduces in estimating the overall spatial resolution of PET scanners will increase as the performance of newer devices improves.

Neutral beam microscopy with a reciprocal space approach using magnetic beam spin encoding

The emerging technique of neutral beam microscopy offers a non-perturbative way of imaging surfaces of various materials which cannot be studied using conventional microscopes. Current neutral beam microscopes use either diffractive focusing or pin-hole scanning to achieve spatial resolution, and are characterised by a strong dependence of the imaging time on the required resolution. In this work we introduce an alternative method for achieving spatial resolution with neutral atom beams which is based on manipulating the magnetic moments of the beam particles in a gradient field, and is characterised by a much weaker dependence of the imaging time on the image resolution. The validity of the imaging approach is demonstrated experimentally by reconstructing one dimensional profiles of the beam which are in good agreement with numerical simulation calculations. Numerical simulations are used to demonstrate the dependence of the signal to noise on the scan resolution and the topography of the sample, and assess the broadening effect due to the spread of velocities of the beam particles. The route towards implementing magnetic encoding in high resolution microscopes is discussed.

The lateral neck in 3 dimensions: A digital model derived from radiology, peer-reviewed literature, and medical illustration

ObjectivesTo develop an anatomically accurate 3-dimensional (3D) digital model of the lateral neck anatomy, including musculature, neurovasculature, and other associated structures such as lymphatics Materials and MethodsLateral neck anatomy, emphasizing level 1-4 structures, were segmented from a CT angiogram of a healthy 29-year-old female which was later transferred into a 3D illustration software after removal of imaging artifacts. To enhance anatomical accuracy, details not captured by imaging or unclear from the study were refined with relevant peer-reviewed literature. These structures were incorporated into the head and neck model. ResultsFollowing segmentation, the 3D models was refined in 3D CAD software. Structures not identified by segmentation, including vagus and phrenic nerves and lymphatics beyond the scan resolution, were designed by a medical illustrator and all structures were refined from peer-reviewed anatomic literature. Where discrepancies were found in the literature, the sample size, source, and methodology of the studies were considered to determine the most common variant of each structure. Finally, the 3D model was uploaded to MedReality® for online viewing. ConclusionThis study demonstrates the critical anatomic structures, landmarks, and surgical relationships relevant to the lateral neck. The associated 3D model and manuscript will serve as a helpful tool for a broad range of clinicians and trainees in search of a detailed 3D anatomic description of the lateral neck. This literature-based model of the central neck combined with 3D anatomic modeling from real patient data should aid in surgical anatomy education.

LASER SCANNING AT THE LOCATION OF DEVILS' TOWN FOR THE PURPOSE OF DETECTING THE DEGREE OF EROSION OF EARTH PILLARS

&amp;lt;p class=&amp;quot;ABSTRACT&amp;quot;&amp;gt;The detection of erosion was carried out on a characteristic rocky pillar, with the localization and quantification of differences between two surfaces. For this purpose, based on the defined area and spatial configuration of the scanning object, scanner positions, arrangement of control points, and appropriate spatial scanning resolution were planned. The spatial resolution of the point cloud is 1 cm, with a standard deviation of individual points up to 3 mm. Based on the collected data, registration of adjacent scenes was performed using typical scanner signals and the surface matching method. Georeferencing of the second epoch was carried out using the surface matching method. Locations where erosion of the rocky mass occurred were detected, amounting to 0.036 m&amp;amp;sup3; (36 dm&amp;amp;sup3;).&amp;lt;/p&amp;gt;

26‐5: Feasibility Analysis of Image Sensors Scanner on Glass

Image sensors on silicon have the problems of small size and high cost. Therefore, we propose a method for making image sensors on glass substrates and analyzes the feasibility of replacing Image Sensors on Silicon from the performance and cost. Through calculation and measurement, the scanning resolution, conversion gain, signal‐to‐noise ratio, and scanning time of image sensors on glass substrates can all meet the requirements of the document scanner and barcode scanner; In addition, the image sensors on glass can be formed in large size and does not require splicing, resulting in lower costs compared to image sensors on silicon of the document scanner. Therefore, image sensors on glass can replace image sensors on silicon of the document scanner. The cost and the module size of the barcode scanner is higher than the existing product, So image sensors on glass used for barcode scanners is lack of advantages in application.

Super-resolution of diffusion-weighted images using space-customized learning model.

Diffusion-weighted imaging (DWI) is a noninvasive method used for investigating the microstructural properties of the brain. However, a tradeoff exists between resolution and scanning time in clinical practice. Super-resolution has been employed to enhance spatial resolution in natural images, but its application on high-dimensional and non-Euclidean DWI remains challenging. This study aimed to develop an end-to-end deep learning network for enhancing the spatial resolution of DWI through post-processing. We proposed a space-customized deep learning approach that leveraged convolutional neural networks (CNNs) for the grid structural domain (x-space) and graph CNNs (GCNNs) for the diffusion gradient domain (q-space). Moreover, we represented the output of CNN as a graph using correlations defined by a Gaussian kernel in q-space to bridge the gap between CNN and GCNN feature formats. Our model was evaluated on the Human Connectome Project, demonstrating the effective improvement of DWI quality using our proposed method. Extended experiments also highlighted its advantages in downstream tasks. The hybrid convolutional neural network exhibited distinct advantages in enhancing the spatial resolution of DWI scans for the feature learning of heterogeneous spatial data.

Technical note: Micro-computed tomography calibration using dental tissue for bone mineral research.

Computed tomography (CT) and microcomputed tomography (μCT) require calibration against density phantoms scanned with specimens or during routine internal calibration for assessment of mineral concentration (MC) and density. In clinical studies involving bone, alternative calibration methods using bodily tissues and fluids ("phantomless" calibration) have been suggested. However, such tissues are seldom available in archeological and osteological research. This study investigates the potential of dental tissue as internal reference for calibration of μCT scans, facilitating the analysis of bone MC. We analyzed 70 molars from 24 extant primate species, including eight human teeth, each scanned with density phantoms for calibration. Our findings indicate that sampling specific regions of molars (lateral aspects of the mesial cusps) yields low variation in enamel and dentine MC values, averaging 1.27 g/cm3 (±0.03) for dentine and 2.25 g/cm3 (±0.03) for enamel. No significant differences were observed across molar types or amongscanning procedures, including scanner model, resolution, and filters. An ad hoc test on 12 mandibles revealed low variance in MC between the conventional phantom and dental tissue calibration methods; all 36 measurements (low, medium, and high MC for each mandible) were within 0.05 g/cm3 of each other -81% were within 0.03 g/cm3 and 94% within 0.04 g/cm3. Based on these results, we propose a new "phantomless" calibration technique using these mean enamel and dentine MC values. The presented phantomless calibration method could aid in the assessment of bone pathology and enhance the scope of studies investigating bone structure and physical property variations in archeological, osteological, and laboratory-based research.

Unified protocol to evaluate intraoral scanner resolution, trueness and precision: the RTP-protocol

Over the past decade, studies published on the evaluation of intraoral scanners (IOSs) have mainly considered two parameters, precision and trueness, to determine accuracy. The third parameter, resolution, not much studied, seems essential for an application in dentistry. Objective: The objective of this preliminary study is to create an original method – a Resolution-Trueness- Precision (RTP) protocol to evaluate these three main parameters – resolution trueness and precision – at the same time. Material and Method: A ceramic tip with particular and calibrated dimensions is determined as the reference object and its mesh recorded with a scanning microtomograph, and compared with the one extracted to the IOS. It is the particular geometric shape of the object that will make it possible to simultaneously assess: resolution, trueness and precision. Results: The results have shown a mean resolution of 79.2 μm, a mean for trueness of 17.5 and a mean for precision of 12.3 μm. These values are close to previous results published for this camera. So, the RTP protocol is the first including the three parameters at the same time. Simple, fast and precise, its application can be useful for comparisons between IOSs within research laboratories or test organizations. Finally, this study could be a first step to create a reference kit for practitioners allowing them to control the quality of their IOS over time.

Extended-Aperture Shape Measurements Using Spatially Partially Coherent Illumination (ExASPICE).

We have recently demonstrated that the 3D shape of micro-parts can be measured using LED illumination based on speckle contrast evaluation in the recently developed SPICE profilometry (shape measurements based on imaging with spatially partially coherent illumination). The main advantage of SPICE is its improved robustness and measurement speed compared to confocal or white light interferometry. The limited spatial coherence of the LED illumination is used for depth discrimination. An electrically tunable lens in a 4f-configuration is used for fast depth scanning without mechanically moving parts. The approach is efficient, takes less than a second to capture required images, is eye-safe and offers a depth of focus of a few millimeters. However, SPICE's main limitation is its assumption of a small illumination aperture. Such a small illumination aperture affects the axial scan resolution, which dominates the measurement uncertainty. In this paper, we propose a novel method to overcome the aperture angle limitation of SPICE by illuminating the object from different directions with several independent LED sources. This approach reduces the full width at half maximum of the contrast envelope to one-eighth, resulting in a twofold improvement in measurement accuracy. As a proof of concept, shape measurements of various metal objects are presented.

Volume microscopic analysis of membrane contact sites in mouse kidney renal proximal tubule epithelial cells

Subcellular organelles communicate with one another and with the plasma membrane (PM). A wide variety of membrane contact sites (MCS) tether subcellular structures to one another and mediate inter-organelle communication and exchange. The nature, distribution and function of membrane contact sites within the segment-specific architecture of renal epithelial cells has only just begun to be elucidated. We have used advanced imaging techniques, including Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) and machine learning-based segmentation, to create a comprehensive, high resolution, 3D and quantifiable volume microscopic atlas of the ultrastructure of proximal tubule epithelial cells of the mouse kidney. We applied this data set to identify and quantify MCS between the endoplasmic reticulum and mitochondria and the PM in these cells. FIB-SEM was performed on a 50 μm by 50 μm by 44 μm block of tissue prepared from the renal cortex of a perfusion fixed 12-week-old male mouse. OsO4-stained tissue was embedded in Durcupan and a 3D X-ray tomogram of the block was used to select a volume of interest that included extended lengths of multiple proximal tubule (PT). The volume was imaged by a customized enhanced FIB-SEM system. The X-Y scanning resolution was set to 4-nm, and 4-nm FIB milling was used to expose surfaces for successive imaging. Generation of the complete image stack required ~11,000 cycles of scanning/FIB ablation over ~4 weeks of uninterrupted imaging. Segmentation of the resultant image set was performed with Zeiss Arivis Pro technology. The boundary box for reconstruction had the dimensions of 29.2 μm x 24.8 μm x 8 μm with a volume of 5793.280 μm3 comprising of 2000 consecutive images at an isotropic voxel size of 4 nm. Deep learning segmentation teased apart 10 cells with distinct boundaries in the PT structure. The volume of the cells in our clipped volume ranged from 8.79 μm3 to 1438.53 μm3 with a median of 45.20 μm3. In one representative proximal tubule cell the volume of mitochondria makes up 84.91 μm3 (31.62%) of the cell volume and the volume of Endoplasmic Reticulum (ER) makes up 23.92 μm3 (8.91%) of the cell volume. The 3D reconstruction and quantitative analysis revealed that there is one dominant ER object accounting for most of the ER volume in the whole cell: i.e., the largest ER object takes up 22.37 μm3 or 93.5% of the ER volume in the cell. A post deep-learning processing algorithm used 3D object modifications to identify 11,109 3D MCS between mitochondria and ER in the 10 cells. The Mito-ER MCS ranged from 512 nm3 to 354,304 nm3 with a median volume of 1792 nm3. Visually we can see Mito-ER and Mito-PM MCS extending across a region of up to ~45 nm between the two organelles. Taken together, these data show that the basal lateral surfaces of PT cell PMs are generously invested with fenestrated smooth ER, as are mitochondria and peroxisomes. Extensive regions of direct contact between mitochondria and PM are also observed. The biochemical identities of these contacts and their physiological functions are being actively pursued. NIDDK DK072612 NIDDK DK120534. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Advantages and Challenges of Total-Body PET/CT at a Tertiary Cancer Center: Insights from Sun Yat-sen University Cancer Center.

In recent decades, researchers worldwide have directed their efforts toward enhancing the quality of PET imaging. The detection sensitivity and image resolution of conventional PET scanners with a short axial field of view have been constrained, leading to a suboptimal signal-to-noise ratio. The advent of long-axial-field-of-view PET scanners, exemplified by the uEXPLORER system, marked a significant advancement. Total-body PET imaging possesses an extensive scan range of 194 cm and an ultrahigh detection sensitivity, and it has emerged as a promising avenue for improving image quality while reducing the administered radioactivity dose and shortening acquisition times. In this review, we elucidate the application of the uEXPLORER system at the Sun Yat-sen University Cancer Center, including the disease distribution, patient selection workflow, scanning protocol, and several enhanced clinical applications, along with encountered challenges. We anticipate that this review will provide insights into routine clinical practice and ultimately improve patient care.

Resolução espacial de um tomógrafo PET de pequenos animais usando o isótopo &lt;sup&gt;68&lt;/sup&gt;Ga

Nuclear Medicine is a modality that has been growing a lot in Brazil and in the world, bringing new radiopharmaceuticals and technologies for the diagnosis and treatment of diseases, making them more effective and accurate. In the development of new radiopharmaceuticals for use in positron emission tomography (PET), the preclinical studies step largely uses PET scanners dedicated to small animals. To achieve this, quality control tests must be carried out to ensure the efficiency of the equipment. Thus, this work aimed to evaluate the spatial resolution of the small animals PET scanner of the CDTN using the isotope 68Ga. In this sense, a microPET hot rod phantom and a commercial 68Ge/68Ga generator were used to obtain PET images. The analysis of the 68Ga-PET images of the simulator was carried out qualitatively and quantitatively and revealed that the spatial resolution of the system using the 68Ga is 3.5 mm.

Evaluation of Reliability of Dynamic Scapholunate Distance Measured on 4D CT-Acquired Images

Abstract Purpose A technique to measure scapholunate distance based on four-dimensional computed tomography (4D CT)-acquired images is presented. Methods Intra-observer variability was evaluated through a repeated-measures study. A 4D CT of seven patients suspected of scapholunate lesion was performed. Anatomical landmarks were identified on a three-dimensional reconstructed model of the wrist. All 4D CT datasets were evaluated thrice by two observers. Standard deviation of the differences between two measurements, interclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated. Results Intra-observer variability for the expert observer (ICC &gt; 0.95) was lower than that of the novice observer (ICC &gt; 0.77) and interobserver variability was low (ICC &gt; 0.85). For the expert observer, measurement error (SEM &lt; 0.13 mm and MDC &lt; 0.36 mm) was smaller than that of the novice observer (SEM &lt; 0.45 mm and MDC &lt; 1.24 mm). Both SEM and MDC values were low, compared to the scan resolution and the absolute value of intervals. Conclusion The proposed assessment results in a reproducible and reliable measurement of scapholunate distance.

High-Temporal-Resolution Kinetic Modeling of Lung Tumors with Dual-Blood Input Function Using Total-Body Dynamic PET.

The lungs are supplied by both the pulmonary arteries carrying deoxygenated blood originating from the right ventricle and the bronchial arteries carrying oxygenated blood downstream from the left ventricle. However, this effect of dual blood supply has never been investigated using PET, partially because the temporal resolution of conventional dynamic PET scans is limited. The advent of PET scanners with a long axial field of view, such as the uEXPLORER total-body PET/CT system, permits dynamic imaging with high temporal resolution (HTR). In this work, we modeled the dual-blood input function (DBIF) and studied its impact on the kinetic quantification of normal lung tissue and lung tumors using HTR dynamic PET imaging. Methods: Thirteen healthy subjects and 6 cancer subjects with lung tumors underwent a dynamic 18F-FDG scan with the uEXPLORER for 1 h. Data were reconstructed into dynamic frames of 1 s in the early phase. Regional time-activity curves of lung tissue and tumors were analyzed using a 2-tissue compartmental model with 3 different input functions: the right ventricle input function, left ventricle input function, and proposed DBIF, all with time delay and dispersion corrections. These models were compared for time-activity curve fitting quality using the corrected Akaike information criterion and for differentiating lung tumors from lung tissue using the Mann-Whitney U test. Voxelwise multiparametric images by the DBIF model were further generated to verify the regional kinetic analysis. Results: The effect of dual blood supply was pronounced in the high-temporal-resolution time-activity curves of lung tumors. The DBIF model achieved better time-activity curve fitting than the other 2 single-input models according to the corrected Akaike information criterion. The estimated fraction of left ventricle input was low in normal lung tissue of healthy subjects but much higher in lung tumors (∼0.04 vs. ∼0.3, P < 0.0003). The DBIF model also showed better robustness in the difference in 18F-FDG net influx rate [Formula: see text] and delivery rate [Formula: see text] between lung tumors and normal lung tissue. Multiparametric imaging with the DBIF model further confirmed the differences in tracer kinetics between normal lung tissue and lung tumors. Conclusion: The effect of dual blood supply in the lungs was demonstrated using HTR dynamic imaging and compartmental modeling with the proposed DBIF model. The effect was small in lung tissue but nonnegligible in lung tumors. HTR dynamic imaging with total-body PET can offer a sensitive tool for investigating lung diseases.

Classification of Malaysian individuals using Fordisc 3 based on four craniofacial measurements

ABSTRACT Fordisc is a discriminant function computer program used to study ancestry, although it lacks representation from a Malaysian sample. Our aim was to evaluate ancestry estimates of Fordisc 3 with Malaysian crania of known sex and ethnicity. A dataset from Hisham and Ibrahim of 300 individuals was included in this study. They had undergone full-body computed tomographic scanning prior to post-mortem examination with scan resolutions of 1.0 mm. Maximum cranial length, maximum cranial breadth, nasal height, nasal breadth, and midorbital width were obtained from these images. Measurements were fed into the Fordisc 3 program and were analysed using the Forensic Anthropology Data Bank (FDB) and Howells’ reference populations according to sex, however midorbital width was excluded in all analyses. Ancestry assessment was evaluated on the basis of percentage of correctly classified individuals. Based on Howells database, 50.67% of the sample are correctly classified into Asian, in contrast to only 32.33% according to FDB. These classification trends are limited by the number of measurements, reference populations available in Fordisc and population history of the sample itself. We need to collect standard anthropological measurements in future research and potentially contribute to the database in Fordisc to improve its performance.