BACKGROUND: The aim of our current systematic dynamic phantom study was first, to optimize reconstruction parameters of coronary CTA (CCTA) acquired on photon counting CT (PCCT) for coronary artery calcium (CAC) scoring, and second, to assess the feasibility of calculating CAC scores from CCTA, in comparison to reference calcium scoring CT (CSCT) scans.
METHODS: In this phantom study, an artificial coronary artery was translated at velocities corresponding to 0, < 60, and 60-75 beats per minute (bpm) within an anthropomorphic phantom. The density of calcifications was 100 (very low), 200 (low), 400 (medium), and 800 (high) mgHA/cm3, respectively. CCTA was reconstructed with the following parameters: virtual non-iodine (VNI), with and without iterative reconstruction (QIR level 2, QIR off, respectively); kernels Qr36 and Qr44f; slice thickness/increment 3.0/1.5 mm and 0.4/0.2 mm. The agreement in risk group classification between CACCCTA and CACCSCT scoring was measured using Cohen weighted linear κ with 95% CI.
RESULTS: For CCTA reconstructed with 0.4 mm slice thickness, calcium detectability was perfect (100%). At < 60 bpm, CACCCTA of low, and medium density calcification was underestimated by 53%, and 15%, respectively. However, CACCCTA was not significantly different from CACCSCT of very low, and high-density calcifications. The best risk agreement was achieved when CCTA was reconstructed with QIR off, Qr44f, and 0.4 mm slice thickness (κ = 0.762, 95% CI 0.671-0.853).
CONCLUSIONS: In this dynamic phantom study, the detection of calcifications with different densities was excellent with CCTA on PCCT using thin-slice VNI reconstruction. Agatston scores were underestimated compared to CSCT but agreement in risk classification was substantial.
CONCLUSIONS: Photon counting CT may enable the implementation of coronary artery calcium scoring from coronary CTA in daily clinical practice.
CONCLUSIONS: Photon-counting CTA allows for excellent detectability of low-density calcifications at all heart rates. Coronary artery calcium scoring from coronary CTA acquired on photon counting CT is feasible, although improvement is needed. Adoption of the standard acquisition and reconstruction protocol for calcium scoring is needed for improved quantification of coronary artery calcium to fully employ the potential of photon counting CT.

Understanding ethnic variations in body composition is crucial for assessing health risks. Universal models may not suit all ethnicities, and there is limited data on the Inuit population. This study aimed to compare body composition between Inuit and European adults using computed tomography (CT) scans and to investigate the influence of demographics on these measurements. A retrospective analysis was conducted on 50 adults (29 Inuit and 21 European) who underwent standard trauma CT scans. Measurements focused on skeletal muscle index (SMI), various fat indices, and densities at the third lumbar vertebra level, analyzed using the Wilcoxon-Mann-Whitney test and multiple linear regression. Inuit women showed larger fat tissue indices and lower muscle and fat densities than European women. Differences in men were less pronouncehd, with only Intramuscular fat density being lower among Inuit men. Regression indicated that SMI was higher among men, and skeletal muscle density decreased with Inuit ethnicity and age, while visceral fat index was positively associated with age. This study suggests ethnic differences in body composition measures particularly among women, and indicates the need for Inuit-specific body composition models. It higlights the importance of further research into Inuit-specific body composition measurements for better health risk assessment.

BACKGROUND: The mortality of oral squamous cell cancer (OSCC) in Serbia increased in the last decade. Recent studies on the Serbian population focused mainly on the epidemiological aspect of OSCC. This study aimed to investigate the demographic and imaging features of OSCC in the Serbian population at the time of diagnosis.
METHODS: We retrospectively analyzed computed tomography (CT) images of 276 patients with OSCC diagnosed between 2017 and 2022. Age, gender, tumor site, tumor volume (CT-TV, in cm3), depth of invasion (CT-DOI, in mm), and bone invasion (CT-BI, in %) were evaluated. TNM status and tumor stage were also analyzed. All parameters were analyzed with appropriate statistical tests.
RESULTS: The mean age was 62.32 ± 11.39 and 63.25 ± 11.71 for males and females, respectively. Male to female ratio was 1.63:1. The tongue (36.2%), mouth floor (21.0%), and alveolar ridge (19.9%) were the most frequent sites of OSCC. There was a significant gender-related difference in OSCC distribution between oral cavity subsites (Z=-4.225; p < 0.001). Mean values of CT-TV in males (13.8 ± 21.5) and females (5.4 ± 6.8) were significantly different (t = 4.620; p < 0.001). CT-DOI also differed significantly (t = 4.621; p < 0.001) between males (14.4 ± 7.4) and females (10.7 ± 4.4). CT-BI was detected in 30.1%, the most common in the alveolar ridge OSCC. T2 tumor status (31.4%) and stage IVA (28.3%) were the most dominant at the time of diagnosis. Metastatic lymph nodes were detected in 41.1%.
CONCLUSIONS: Our findings revealed significant gender-related differences in OSCC imaging features. The predominance of moderate and advanced tumor stages indicates a long time interval to the OSCC diagnosis.

OBJECTIVE: To determine the accuracy of computed tomography (CT)-based staging in selecting high-risk colon cancer patients who would benefit from neoadjuvant chemotherapy while avoiding overtreatment.
METHODS: Data of adult patients diagnosed with non-metastatic primary colon cancer in 2005-2020, who underwent surgical resection without neoadjuvant chemotherapy, were retrospectively collected from the Netherlands Cancer Registry. Agreement between clinical and pathological evaluation for each T and N stage was calculated. Sensitivity and specificity analyses were conducted to predict T3-T4 and N1-N2 stages, with histopathology as the reference standard.
RESULTS: Data from 44,471 patients (median age, 71 years, 50% female) were evaluated. We included 38,915 patients with complete T stage and 39,565 patients with complete N stage for analyses. The overall clinical-pathological agreement for T stage was 59% and for N stage 57%. The sensitivity and specificity of CT to detect T3-T4 tumours were 80% (95% confidence interval (CI): 0.79, 0.80) and 76% (95% CI: 0.75, 0.77), respectively, with a positive predictive value (PPV) of 92% (95% CI: 0.92, 0.92). The sensitivity and specificity of CT to detect N1-N2 category were 62% (95% CI: 0.61, 0.63) and 70% (95% CI: 0.69, 0.71), respectively, with PPV 60% (95% CI: 0.59, 0.60).
CONCLUSIONS: CT-based staging shows limited accuracy in selecting colon cancer patients who would benefit from neoadjuvant therapy without risking overtreatment. Detection of lymph node metastases with CT remains unreliable.

BACKGROUND: The surgical approach and prognosis for invasive adenocarcinoma (IAC) and minimally invasive adenocarcinoma (MIA) of the lung differ. However, they both manifest as identical ground-glass nodules (GGNs) in computed tomography images, and no effective method exists to discriminate them.
METHODS: We developed and validated a three-dimensional (3D) deep transfer learning model to discriminate IAC from MIA based on CT images of GGNs. This model uses a 3D medical image pre-training model (MedicalNet) and a fusion model to build a classification network. Transfer learning was utilized for end-to-end predictive modeling of the cohort data of the first center, and the cohort data of the other two centers were used as independent external validation data. This study included 999 lung GGN images of 921 patients pathologically diagnosed with IAC or MIA at three cohort centers.
RESULTS: The predictive performance of the model was assessed using the area under the receiver operating characteristic curve (AUC). The model had high diagnostic efficacy for the training and validation groups (accuracy: 89%, sensitivity: 95%, specificity: 84%, and AUC: 95% in the training group; accuracy: 88%, sensitivity: 84%, specificity: 93%, and AUC: 92% in the internal validation group; accuracy: 83%, sensitivity: 83%, specificity: 83%, and AUC: 89% in one external validation group; accuracy: 78%, sensitivity: 80%, specificity: 77%, and AUC: 82% in the other external validation group).
CONCLUSIONS: Our 3D deep transfer learning model provides a noninvasive, low-cost, rapid, and reproducible method for preoperative prediction of IAC and MIA in lung cancer patients with GGNs. It can help clinicians to choose the optimal surgical strategy and improve the prognosis of patients.

UNASSIGNED: Pancreatoduodenectomy (PD) is recommended in fit patients with a carcinoma (PDAC) of the pancreatic head, and a delayed resection may affect survival. This study aimed to correlate the time from staging to PD with long-term survival, and study the impact of preoperative investigations (if any) on the timing of surgery.
UNASSIGNED: Data were extracted from the Recurrence After Whipple\'s (RAW) study, a multicentre retrospective study of PD outcomes. Only PDAC patients who underwent an upfront resection were included. Patients who received neoadjuvant chemo-/radiotherapy were excluded. Group A (PD within 28 days of most recent preoperative computed tomography [CT]) was compared to group B (> 28 days).
UNASSIGNED: A total of 595 patents were included. Compared to group A (median CT-PD time: 12.5 days, interquartile range: 6-21), group B (49 days, 39-64.5) had similar one-year survival (73% vs. 75%, p = 0.6), five-year survival (23% vs. 21%, p = 0.6) and median time-todeath (17 vs. 18 months, p = 0.8). Staging laparoscopy (43 vs. 29.5 days, p = 0.009) and preoperative biliary stenting (39 vs. 20 days, p < 0.001) were associated with a delay to PD, but magnetic resonance imaging (32 vs. 32 days, p = 0.5), positron emission tomography (40 vs. 31 days, p > 0.99) and endoscopic ultrasonography (28 vs. 32 days, p > 0.99) were not.
UNASSIGNED: Although a treatment delay may give rise to patient anxiety, our findings would suggest this does not correlate with worse survival. A delay may be necessary to obtain further information and minimize the number of PD patients diagnosed with early disease recurrence.

Since class II malocclusion and lack of space within the dental arch due to early loss of deciduous molars is a common orthodontic problem in the Polish population, bone-anchored distalizers are becoming more and more popular. The aim of the present study was to evaluate palatal soft and hard tissue thickness using cone beam computed tomography (CBCT) at the area of micro-implant placement of two appliances for maxillary first molar distalization: Beneslider and TopJet distalizer. The study data were 100 consecutively selected CBCT images (53 of men and 47 of women). Measurements of bone and mucosa thickness were performed at six locations in the palate and tested according to their correlation with sex and age. The biggest bone and mucosa thickness were recorded in the insertion site of the TopJet miniscrew. Bone thickness in all points of paramedian insertion was significantly greater in males and the mean difference was approximately 1-1.8 mm. Age correlates significantly (p < 0.05) and positively (r > 0) with the thickness of the mucosa at all points: the older the patient, the thicker the mucosa at each measurement point. Anatomical diversity of the hard palate in the population involves the need to perform bone and mucosa thickness measurements before palatal micro-implant placement.

Helical mandibular distraction is theoretically better than linear or circular distraction. However, it is not known whether this more complex treatment will result in unquestionably better outcomes. Therefore, the best attainable outcomes of mandibular distraction osteogenesis were evaluated in silico, given the constraints of linear, circular, and helical motion. This cross-sectional kinematic study included 30 patients with mandibular hypoplasia who had been treated with distraction, or to whom this treatment had been recommended. Demographic information and the computed tomography (CT) scans showing the baseline deformity were collected. The CT scans of each patient were segmented and three-dimensional models of the face created. Then, the ideal distraction outcomes were simulated. Next, the most favorable helical, circular, and linear distraction movements were calculated. Finally, errors were measured: misalignment of key mandibular landmarks, misalignment of the occlusion, and changes in intercondylar distance. Helical distraction produced trivial errors. In contrast, circular and linear distractions resulted in errors that were statistically and clinically significant. Helical distraction also preserved the planned intercondylar distance, while circular and linear distractions led to unwanted changes in the intercondylar distance. It is now evident that helical distraction offers a new strategy to improve the outcomes of mandibular distraction osteogenesis.

Floral shape (relative arrangement and position of floral organs) is critical in mediating fit with pollinators and maximizing conspecific pollen transfer particularly in functionally specialized systems. To date, however, few studies have attempted to quantify flowers as the inherently three-dimensional (3D) structures they are and determine the effect of intraspecific shape variation on pollen transfer. We here addressed this research gap using a functionally specialized system, buzz pollination, in which bees extract pollen through vibrations, as a model. Our study species, Meriania hernandoi (Melastomataceae), undergoes a floral shape change from pseudocampanulate corollas with more actinomorphically arranged stamens (first day) to open corollas with a more zygomorphic androecium (second day) over anthesis, providing a natural experiment to test how variation in floral shape affects pollination performance.
In one population of M. hernandoi, we bagged 51 pre-anthetic flowers and exposed half of them to bee pollinators when they were in either stage of their shape transition. We then collected flowers, obtained 3D flower models through x-ray computed tomography for 3D geometric morphometric analyses, and counted the pollen grains remaining per stamen (male pollination performance) and stigmatic pollen loads (female pollination performance).
Male pollination performance was significantly higher in open flowers with zygomorphic androecia than in pseudo-campanulate flowers. Female pollination performance did not differ among floral shapes.
These results suggest that there is an \"optimal\" shape for male pollination performance, while the movement of bees around the flower when buzzing the spread-out stamens results in sufficient pollen deposition regardless of floral shape.

Rationale: Chest computed tomography is performed in patients with empyema for various reasons. However, its predictive ability for patient outcomes in empyema has not been evaluated. Objectives: To evaluate the predictive ability of computed tomography findings (pleural thickness, loculation, interlobar pleural effusion, lung abscess, and bronchopleural fistula) for 90-day mortality in empyema. Methods: This multicenter retrospective cohort study was conducted across six acute care hospitals in Japan. We included patients with confirmed empyema diagnoses who underwent chest computed tomography within 7 days of diagnosis. Imaging findings were defined as pleural thickness, loculation, interlobar pleural effusion, lung abscess, or bronchopleural fistula. One radiologist interpreted the computed tomography scans without patient information. The primary outcome was 90-day mortality. We calculated the differences in 90-day mortality between the presence and absence of each computed tomography finding using logistic regression with or without adjustment for early thoracic surgery. Results: A total of 711 patients were included in our study. Thoracic surgery was performed in 27% of patients, and the 90-day mortality rate was 10%. The differences (95% confidence intervals) in 90-day mortality without and with adjustment for early thoracic surgery were as follows: pleural thickness, 3.09% (-1.35% to 7.54%) and 2.70% (-1.80% to 7.20%); loculation, -4.01% (-8.61% to 0.60%) and -3.80% (-8.41% to 0.81%); interlobar pleural effusion, -9.15% (-14.58% to -3.72%) and -8.96% (-14.39% to -3.53%); lung abscess, 7.04% (-1.16% to 15.2%) and 6.86% (-1.34% to 15.05%); and bronchopleural fistula, 13.80% (7.66% to 19.94%) and 13.63% (7.50% to 19.77%), respectively. Conclusions: Although interlobar pleural effusion predicted lower 90-day mortality regardless of early thoracic surgery, the presence of bronchopleural fistula predicted higher 90-day mortality with empyema. Our results warrant further validation.