Computed Tomography For Detection Research Articles

Evaluation the effect of wide-body detector CT under free breathing combined with cardiac motion correction technology on CCTA image quality

PurposeTo explore the feasibility of using wide-body detector Computed Tomography (CT) combined with Cardiac Motion Correction (CMC) technology for coronary Computed Tomography angiography (CCTA) in free breathing state and its impact on image quality. Methods120 patients who underwent CCTA scans at our institution from March 2023 to December 2023 were collected in this retrospective study. Recorded the coronary artery images before applying CMC technology as the control group, and the images after applying CMC technology as the experimental group. Patients were divided into two groups by different heart rate (HR), Group A (HR > 70 bpm) and Group B (HR ≤ 70 bpm), with 66 patients in group A and 54 patients in group B. Subjective image quality assessments were performed on the left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA) proximal segments. These assessments were conducted by two senior radiologists using a double-blind approach and a 4-point scale (1 indicating poor image quality and 4 indicating excellent image quality). The subjective scores among the three coronary artery segments were analyzed by chi-square test, using Kappa coefficient to analyze the inter-observer agreement. ResultsThe control group had a subjective score of 3.37 ± 0.81/3.27 ± 0.83 for the LCX, 2.97 ± 0.85/2.93 ± 0.78 for the LAD, and 2.70 ± 0.75/2.80 ± 0.66 for the RCA. The experimental group had a subjective score of 3.90 ± 0.31/3.83 ± 0.38 for the LCX, 3.83 ± 0.38/3.87 ± 0.35 for the LAD, and 3.87 ± 0.35/3.83 ± 0.38 for the RCA. There was a great enhancement in the image quality observed in the experimental group when contrasted with the control group both in group A and group B (all P < 0.05). The inter-observer consistency of LCX, LAD and RCA were 0.726, 0.801 and 0.734 in control group and 0.769, 0.870 and 0.870 in experimental group. ConclusionThe utilization of CMC technology significantly enhances the quality of CCTA images acquired during free breathing.

Assessing tissue differentiation capabilities in X-ray imaging through cadmium zinc telluride (CZT) photon counting detectors.

In recent years, the use of photon-counting detection technology has resulted in significant X-ray imaging research. This advanced technology holds considerable promise for enhancing Computed Tomography (CT) scanners, offering a potential solution to the limitations inherent in traditional CT detectors. The ongoing studies are dedicated to assessing the effectiveness and sensitivity of semiconductor detector materials in photon counting detectors, particularly in their ability to detect soft tissue contrasts. This study aimed to characterize the performance of the Cadmium Zinc Telluride (CZT) photon counting detector in identifying various tissues with a focus on assessing its sensitivity in distinguishing tissue types in X-ray imaging. An optimal frame rate per second (FPS) of the CZT detector was evaluated by setting the X-ray tube voltage and current at 25 keV and 35 keV and 0.5 mA, 1.0 mA respectively. By keeping the optimum FPS fixed, the detector energy thresholds were set in small steps from 15 keV to 35 keV and the tube currents were set for X-ray tubes in ranges of 0.1 mA–1.0 mA to evaluate the relationship between voltage and current of the X-ray source and counts per second (CPS). The specimens, including fat, liver, muscles, paraffin wax, and contrast media were placed on a stair-step chamber constructed from Plexi-glass, spanning six distinct thickness levels. We investigated X-ray transmission across these tissue samples at varying thicknesses, exploring five energy thresholds: 21 keV, 25 keV, 29 keV, 31 keV, and 45 keV to evaluate their impact on the CPS. This study found that a frame rate of 12 frames per second optimally aligns with the spectral response of the X-ray source. Furthermore, a linear correlation is present between the CPS and the X-ray tube current. The transmission of X-rays through a sample depends on its thickness, a phenomenon observed across different energy thresholds in this study. The detectors exhibit high sensitivity and linearity, ensuring accurate and reliable measurements in diverse imaging scenarios, making them invaluable tools for precise data acquisition in both research and clinical applications.

Advanced Imaging of Total Knee Arthroplasty.

The prevalence of total knee arthroplasty (TKA) is increasing with the aging population. Although long-term results are satisfactory, suspected postoperative complications often require imaging with the implant in place. Advancements in computed tomography (CT), such as tin prefiltration, metal artifact reduction algorithms, dual-energy CT with virtual monoenergetic imaging postprocessing, and the application of cone-beam CT and photon-counting detector CT, allow a better depiction of the tissues adjacent to the metal. For magnetic resonance imaging (MRI), high bandwidth (BW) optimization, the combination of view angle tilting and high BW, as well as multispectral imaging techniques with multiacquisition variable-resonance image combination or slice encoding metal artifact correction, have significantly improved imaging around metal implants, turning MRI into a useful clinical tool for patients with suspected TKA complications.

LEAFLETS AND EXTRA–LEAFLETS HYPOATTENUATED LESIONS FOLLOWING TAVR

Abstract Introduction Subclinical leaflets thrombosis is a condition diagnosed with multi–detector computer tomography (MDCT) characterized by a meniscal–shaped hypoattenuated lesion of one or more leaflets. Transcatheter aortic self–expandable valves are commonly manufactured with pliable pericardium over a nitinol frame that forms the leaflets and the extra–leaflets components, such as the valve skirt. Little is known about extra–leaflets hypoattenuated lesions localization, including the anatomic sinus level. Methods This was an ambi–directional study. Fifty patients underwent MDCT at follow–up. Results At mean follow–up was of 12 months, hypoattenuated leaflet lesion with mild to severe restricted movement was detected in 8 individuals (16%); anatomic sinus lesion was identified in 9 patients (18%) with higher prevalence in the non–coronary sinus (16%); subvalvular lesion with a variable extension toward the valve inflow, was diagnosed in 8 patients (16%). In 4 patients (8%) the anatomic sinus thrombus was ‘in overlap’ with the leaflet thrombus; in 3 patients (6%) was in continuity with the subvalvular frame thrombus. Bicuspid valve was the only independent predictor associated with hypoattenuated lesions (adj OR 8.25 (95% CI: 1.38, 49.21), p=0.02). Conclusions This study demonstrated that hypoattenuated lesions could be identified not only at leaflet, but also at subvalvular and anatomic sinus level. The clinical relevance of such lesions remains uncertain.

The tibial tubercle-to-trochlear groove distance changes in standing weight-bearing condition: An upright weight-bearing computed tomography analysis

BackgroundThe tibial tubercle-to-trochlear groove (TT-TG) distance and Insall-Salvati (I/S) ratio are widely used to determine the need for distal realignment in conjunction with medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent patellar dislocation. A TT-TG distance >20 mm and an I/S ratio >1.3 are significant anatomical risk factors for patellar instability. However, these parameters have traditionally been measured using non-weight-bearing (NWB) imaging modalities. As patellar dislocation occurs during weight-bearing actions, these two parameters should be measured under weight-bearing conditions. Thus, this study aimed to measure the TT-TG distance and I/S ratio using upright full-weight-bearing (FWB) computed tomography (CT) scans and compare the data with NWB CT scans. MethodsThis study included 49 knee joints of 26 healthy volunteers. CT images were obtained under both FWB and NWB standing conditions using a 320-detector row upright CT scanner. TT-TGs in the axial plane and I/S ratios in the sagittal plane were measured and compared. ResultsThe average FWB TT-TG distance was 20.3 ± 3.9 mm, whereas the average NWB TT-TG distance was 12.3 ± 4.7 mm. The TT-TG level was significantly higher in the FWB condition than that in the NWB condition (P < 0.001). The I/S ratios were comparable between the FWB and NWB conditions (P = 0.29). ConclusionsThe TT-TG distance in the standing weight-bearing condition was larger than the conventional TT-TG distance and surpassed the historical cutoff value of TT-TG, which may affect the indication of additional distal realignment in MPFL reconstruction for patellar instability.

Significance of upper cervical epidural venous engorgement on head computed tomography in the initial diagnosis of spontaneous intracranial hypotension: patient series.

Spontaneous intracranial hypotension (SIH) is a rare condition characterized by positional headache, for which contrast-enhanced magnetic resonance imaging (MRI) is the preferred diagnostic method. Although MRI reveals characteristic findings, head computed tomography (CT) is usually the first diagnostic step, but identifying features of SIH on CT is often difficult. This study was specifically designed to evaluate the utility of head CT in detecting upper cervical epidural venous engorgement as a sign of SIH. Of 24 patients with SIH diagnosed between March 2011 and May 2023, 10 did not undergo upper cervical CT. In the remaining 14 patients, engorgement of the upper cervical epidural venous plexus was observed. CT detection rates were consistent with MRI for spinal fluid accumulation or dural thickening. After treatment, in 92.9% of patients, the thickness of the epidural venous plexus decreased statistically significantly from 4.8 ± 1.3 mm to 3.6 ± 1.2 mm. This study suggests that upper cervical spine CT focused on epidural venous engorgement may be helpful in the initial diagnosis of SIH and may complement conventional MRI evaluation. Extending CT imaging to the upper cervical spine will improve the diagnostic accuracy of patients with positional headaches suspected to be SIH.

First experimental evaluation of a high-resolution deep silicon photon-counting sensor.

Current photon-counting computed tomography detectors are limited to a pixel size of around 0.3 to 0.5mm due to excessive charge sharing degrading the dose efficiency and energy resolution as the pixels become smaller. In this work, we present measurements of a prototype photon-counting detector that leverages the charge sharing to reach a theoretical sub-pixel resolution in the order of . The goal of the study is to validate our Monte-Carlo simulation using measurements, enabling further development. We measure the channel response at the MAX IV Lab, in the DanMAX beamline, with a 35keV photon beam, and compare the measurements with a 2D Monte Carlo simulation combined with a charge transport model. Only a few channels on the prototype are connected to keep the number of wire bonds low. The measurements agree generally well with the simulations with the beam close to the electrodes but diverge as the beam is moved further away. The induced charge cloud signals also seem to increase linearly as the beam is moved away from the electrodes. The agreement between measurements and simulations indicates that the Monte-Carlo simulation can accurately model the channel response of the detector with the photon interactions close to the electrodes, which indicates that the unconnected electrodes introduce unwanted effects that need to be further explored. With the same Monte-Carlo simulation previously indicating a resolution of around with similar geometry, the results are promising that an ultra-high resolution detector is not far in the future.

Photon-Counting Detector CT for Liver Lesion Detection-Optimal Virtual Monoenergetic Energy for Different Simulated Patient Sizes and Radiation Doses.

The aim of this study was to evaluate the optimal energy level of virtual monoenergetic images (VMIs) from photon-counting detector computed tomography (CT) for the detection of liver lesions as a function of phantom size and radiation dose. An anthropomorphic abdominal phantom with liver parenchyma and lesions was imaged on a dual-source photon-counting detector CT at 120 kVp. Five hypoattenuating lesions with a lesion-to-background contrast difference of -30 HU and -45 HU and 3 hyperattenuating lesions with +30 HU and +90 HU were used. The lesion diameter was 5-10 mm. Rings of fat-equivalent material were added to emulate medium- or large-sized patients. The medium size was imaged at a volume CT dose index of 5, 2.5, and 1.25 mGy and the large size at 5 and 2.5 mGy, respectively. Each setup was imaged 10 times. For each setup, VMIs from 40 to 80 keV at 5 keV increments were reconstructed with quantum iterative reconstruction at a strength level of 4 (QIR-4). Lesion detectability was measured as area under the receiver operating curve (AUC) using a channelized Hotelling model observer with 10 dense differences of Gaussian channels. Overall, highest detectability was found at 65 and 70 keV for both hypoattenuating and hyperattenuating lesions in the medium and large phantom independent of radiation dose (AUC range, 0.91-1.0 for the medium and 0.94-0.99 for the large phantom, respectively). The lowest detectability was found at 40 keV irrespective of the radiation dose and phantom size (AUC range, 0.78-0.99). A more pronounced reduction in detectability was apparent at 40-50 keV as compared with 65-75 keV when radiation dose was decreased. At equal radiation dose, detection as a function of VMI energy differed stronger for the large size as compared with the medium-sized phantom (12% vs 6%). Detectability of hypoattenuating and hyperattenuating liver lesions differed between VMI energies for different phantom sizes and radiation doses. Virtual monoenergetic images at 65 and 70 keV yielded highest detectability independent of phantom size and radiation dose.

Detection limit of computed tomography for hepatoblastoma pulmonary metastases: Based on total resection using indocyanine green fluorescence

BackgroundIntraoperative search for small pulmonary metastases of hepatoblastoma has been challenging; therefore, it has been difficult to determine the true detection limit of computed tomography (CT). This is the first report on the detection limit of CT for hepatoblastoma pulmonary metastases in patients who underwent resection of hepatoblastoma pulmonary metastases using indocyanine green fluorescence (ICGF). MethodsWe retrospectively reviewed the CT images of patients who underwent resection of hepatoblastoma pulmonary metastases using ICGF between January 2013 and November 2021 at a single children's hospital and compared them with pathological findings. ResultsOverall, 757 nodules were resected from 20 cases and 75 thoracotomies; 411 nodules were considered for the study and 286 were pathologically positive. The number of nodules classified by size in the pathological sections and the probability of CT detection were as follows: < 2 mm: CT-positive/pathology-positive, 43/144, 29.9 %; ≥ 2 and < 3 mm: 5/10, 50 %; ≥ 3 and < 4 mm: 20/27, 74.1 %; ≥ 4 and < 5 mm: 15/16, 93.8 %; ≥ 5 mm: 87/89, 97.8 %. Of 286 pathology-positive nodules, 59.4 % were CT-positive. With a cut-off value of 3 mm for tumor size, the proportion of CT-positive nodules was 92.4 %. Of 177 CT-positive nodules, 170 were pathologically positive. ConclusionsMore than 90 % of nodules > 3 mm were detectable on CT, whereas less than 30 % of pathologically positive nodules < 2 mm could be detected. In children with hepatoblastoma, a CT-positive pulmonary nodule, even if minute, is likely to be malignant and metastasis should be suspected.

Differentiation of Crohn’s disease, ulcerative colitis, and intestinal tuberculosis by dual-layer spectral detector CT enterography

AIMTo investigate the value of radiological features and energy spectrum quantitative parameters in the differential diagnosis of Crohn’s disease (CD), ulcerative colitis (UC), and intestinal tuberculosis (ITB) by dual-layer spectral detector computed tomography (CT) enterography (CTE). MATERIALS AND METHODSClinical and CTE data were collected from 182 patients with CD, 29 with UC, and 51 with ITB. CT images were obtained at the enteric phases and portal phases. The quantitative energy spectrum parameters were iodine density (ID), normalised ID (NID), virtual non-contrast (VNC) value, and effective atomic number (Z-eff). The area under curve (AUC) of the receiver operating characteristic curve (ROC) was calculated. RESULTSThe vascular comb sign (p=0.009) and enlarged lymph nodes (p=0.001) were more common in patients with CD than UC or ITB. In the differentiation of moderate–severe active CD from UC, enteric phase NID (AUC, 0.938; p<0.001) and portal phase Z-eff (AUC, 0.925; p<0.001) had the highest accuracy, which were compared separately. In the differentiation of moderate–severe active CD from ITB, enteric phase NID (AUC, 0.906; p<0.001) and portal phase Z-eff (AUC, 0.947; p<0.001) had the highest accuracy; however, the AUC value was highest when the four parameters are combined (AUC, 0.989; p<0.001; AUC, 0.986; p<0.001; AUC, 0.936; p<0.001; and AUC, 0.986; p<0.001). CONCLUSIONThe present study shows that the combined strategies of four parameters have higher sensitivity and specificity in differentiating CD, UC, and ITB, and may play a key role in guiding treatment.

Photon counting x-ray detectors as scatter probes.

Direct conversion x-ray Photon Counting Detectors (PCD) are posed to play a vital role in future medical imaging devices such as Computed Tomography (CT) scanners. PCD are expected to improve current CT technology on several fronts, such as resolution, dose utilization, and spectral performance. However, they are not readily expected to improve the handling of object scatter, one of the major sources of image artifacts in CT technology. We explore a potential method for obtaining in-situ object scatter estimation using the same PCD array used in the x-ray imaging system, such as in computed tomography. This unexpected benefit of using PCD has the potential to improve the image quality by providing better input into the scatter estimation and correction algorithms used in image reconstruction. In CT scanners the primary method for rejecting scatter signal originating from the scanned object relies on placing anti-scatter grids (ASG) close to the detector plane. This remains the case when transitioning to using PCD instead of energy integration detectors in CT. However, the combination of PCD and ASG opens a possibility to use some of the unique properties of PCD, namely, very low noise and coincidence counters to obtain, in addition to the attenuation data, a simultaneous and instantaneous estimate of the scatter signal reaching every detector element. When a small air gap is introduced between the ASG and the detector surface, the scatter radiation with large angular distribution has a greater probability of producing charge sharing events that can be detected by a coincidence counter. In this work we demonstrate the feasibility of such an approach in a tabletop experiment using PCD detector that lacks coincidence counting capability, instead we use the spectral signature of split charge events as proxy to coincidence counting. For this purpose, we first demonstrate the spectral impact of ASG misalignment using the same experimental setup. In addition, we perform a separate tabletop scattering experiment from a narrow column of water that demonstrates another potential use of the low noise capabilities of PCDs. We measured and quantified the high sensitivity of the spectral response to ASG alignment on the PCD detector pixel array, we found that the probability of energy misregistration of 60keV photons can increase by up to a factor of 3 when the ASG is poorly aligned. We then leveraged these results to obtain an estimate on the expected increase in coincidence counts for a wide range of scatter-to-primary (SPR) ratio and find a good match with expectations from a geometric modeling of the system, where the expected increase in coincidences was of the order of the SPR. Finally, the low noise detector also allowed us to measure the real space scatter signal associated with the coherent molecular form factor of water, revealing the ring-shaped scatter signal with an energy dependent distribution that was well captured by calculation. The advent of PCD detectors and their imminent use in commercial CT scanners opens new and exciting possibilities for utilizing PCD detectors in unexpected ways. In this proof-of-concept study, we showed how charge sharing, a spectral information degrading effect, can instead be used to obtain in-situ scatter estimation. We also demonstrated the PCD ability to perform extremely sensitive measurements using affordable benchtop setup for investigations normally reserved for synchrotron facilities.

Innovative advances in pediatric radiology: computed tomography reconstruction techniques, photon-counting detector computed tomography, and beyond.

In pediatric radiology, balancing diagnostic accuracy with reduced radiation exposure is paramount due to the heightened vulnerability of younger patients to radiation. Technological advancements in computed tomography (CT) reconstruction techniques, especially model-based iterative reconstruction and deep learning image reconstruction, have enabled significant reductions in radiation doses without compromising image quality. Deep learning image reconstruction, powered by deep learning algorithms, has demonstrated superiority over traditional techniques like filtered back projection, providing enhanced image quality, especially in pediatric head and cardiac CT scans. Photon-counting detector CT has emerged as another groundbreaking technology, allowing for high-resolution images while substantially reducing radiation doses, proving highly beneficial for pediatric patients requiring frequent imaging. Furthermore, cloud-based dose tracking software focuses on monitoring radiation exposure, ensuring adherence to safety standards. However, the deployment of these technologies presents challenges, including the need for large datasets, computational demands, and potential data privacy issues. This article provides a comprehensive exploration of these technological advancements, their clinical implications, and the ongoing efforts to enhance pediatric radiology's safety and effectiveness.

Evaluation of the anatomic sinus after transcatheter aortic valve replacement

Abstract Background Transcatheter aortic valve replacement (TAVR) determines the creation of outer area between the cage and the aortic wall named the ‘anatomic sinus’ (Figure 1 A-B). This newly formed space of the sinuses of Valsalva (SOV) might disrupt the physiological currents of Valsalva and contribute to the formation of subclinical leaflets thrombosis (SLT). The evaluation of the root geometry after TAVR is generally performed with multi detector computer tomography (MDCT), and the role of transthoracic echocardiography (TTE) needs further validation. Purpose The aim of this study was to test reproducibility of 2D TTE assessment of the anatomic sinus dimension with MDCT as reference. We also investigated predictors for SLT. Methods We enrolled 90 patients who underwent TAVR with self-expandable prosthesis. 2D TTE was performed using Philips EPIQ-7, and echocardiograms analysed offline with Philips QLAB cardiac analysis. Both SOV and prosthesis diameters were assessed in long and short-axis parasternal view (PLAX / PSAX) and the bidimensional area of the anatomic sinus was calculated (Figure 2 A-B). Inter-observer (observer 1 – 2) reproducibility was assessed by the means of interclass correlation coefficient (ICC). MDCT was performed in 50 individuals to evaluate concordance (Bland Altman test) with the 2D TTE anatomic sinus area and also to detect SLT (Figure 2 C-D). Multivariable model was built to assess predictors of SLT. Results Mean follow-up was 13.1 months. There was excellent and good correlation with regard to the diameter of the SOV and the prosthesis measured in PLAX view by observer 1 and 2: ICC: 0.93, 95% Confidence Interval (CI) (0.76–0.97), p&amp;lt; 0.001; ICC: 0.87(0.63,0.96), p&amp;lt;0.001, SOV and prosthesis respectively. The correlation found with regard to the diameter of the SOV and the prosthesis measured in PSAX view was also excellent ICC: 0.90(0.68,0.97), p=0.001; and good ICC: 0.88(0.63,0.96), p &amp;lt;0.001, SOV and prosthesis respectively. The anatomic sinus areas assessed by 2D TTE were similar compared to areas derived by MDCT (4.1 ± 1.09 cm2 vs. 4.02 ± 1.55 cm2, respectively, p=0.57). Bland–Altman analysis of anatomic sinus area measured on 2D TTE and MDCT respectively, indicated high level of agreement and no fixed or proportional bias. Native bicuspid valve, but not the anatomic sinus area, was the only independent predictors for SLT. Conclusions Following TAVR, the newly formed anatomic sinus could be assessed with good reproducibility with 2D TTE. We found a significant association between native bicuspid valve and SLT diagnosed with MDCT.Figure 1A-BFigure 2A-D

Thresholding-accelerated convolutional neural network for aeroengine turbine blade segmentation

Turbine blades can only be detected nondestructively and precisely using industrial computed tomography (CT). The accuracy of CT image segmentation, which is a key step in CT detection, significantly affects CT detection precision. However, CT images of turbine blades cannot be segmented precisely because they contain inhomogeneity, noise, artifacts, and low-contrast areas. In addition, it is crucial to consider both efficiency and precision in industrial applications. Unfortunately, large-size networks often tend to be inefficient, while lightweight networks lack the necessary accuracy. To address these issues, we propose an innovative approach utilizing an ultra-lightweight neural network that fuses a threshold-based segmentation algorithm with a convolutional neural network for acceleration. The integrated thresholding algorithm was developed through the convolution of the Phansakar method. The convolutional neural network was designed with a simplified multichannel convolution operation to minimize computational cost. Notably, the proposed neural network utilizes only 0.11 M learnable parameters, which is significantly less than the number utilized by most classical deep neural networks. Experimental results for CFM56-7BE and Pratt & Whitney F100 aeroengine hollow turbine blade CT images demonstrate that compared to state-of-the-art algorithms, our proposed network can achieve 0.44 % mean intersection over union and 0.23 % mean Dive similarity coefficient improvements on testing datasets with significantly reduced computational cost. Therefore, the proposed method has high practical application significance and can achieve real-time detection.

Photon-Counting Detector Computed Tomography Versus Energy-Integrating Detector Computed Tomography for Coronary Artery Calcium Quantitation.

Photon-counting detector (PCD) computed tomography (CT) offers improved spatial and contrast resolution, which can impact quantitative measurements. This work aims to determine in human subjects the effect of dual-source PCD-CT on the quantitation of coronary artery calcification (CAC) compared with dual-source energy-integrating detector (EID) CT in both 1- and 3-mm images. This prospective study enrolled patients receiving a clinical EID-CT CAC examination to undergo a research PCD-CT CAC examination. Axial images were reconstructed with a 512 × 512 matrix, 200-mm field of view, 3-mm section thickness/1.5-mm interval using a quantitative kernel (Qr36). Sharper kernels (Qr56/QIR strength 4 for PCD and Qr49/ADMIRE strength 5 for EID) were used to reconstruct images with 1-mm section thickness/0.5-mm interval. Pooled analysis was performed for all calcifications with nonzero values, and volume and Agatston scores were compared between EID-CT and PCD-CT. A Wilcoxon signed-rank test was performed with P < 0.05 considered statistically significant. In 21 subjects (median age, 58 years; range, 50-75 years; 13 male [62%]) with a total of 42 calcified arteries detected at 3 mm and 46 calcified arteries at 1-mm images, EID-CT CAC volume and Agatston scores were significantly lower than those of PCD-CT ( P ≤ 0.001). At 3-mm thickness, the mean (standard deviation) volume and Agatston score for EID-CT were 55.5 (63.4) mm 3 and 63.8 (76.9), respectively, and 61.5 (69.4) mm 3 and 70.4 (85.3) for PCD-CT ( P = 0.0001 and P = 0.0013). At 1-mm thickness, the mean (standard deviation) volume and score for EID-CT were 50.0 (56.3) mm 3 and 61.1 (69.3), respectively, and 59.5 (63.9) mm 3 and 72.5 (79.9) for PCD-CT ( P < 0.0001 for both). The applied radiation dose (volume CT dose index) for the PCD-CT scan was 2.1 ± 0.6 mGy, which was 13% lower than for the EID-CT scan (2.4 ± 0.7 mGy, P < 0.001). Relative to EID-CT, PCD-CT demonstrated a small but significant increase in coronary artery calcium volume and Agatston score.

Concordance of CT imaging and surgical lesions in penetrating abdominal trauma

The management of penetrating abdominal wounds has greatly benefited from the development of computed tomography (CT), particularly in stable patients. In this setting, the scanner is the reference examination. Our study aims to evaluate the performance of preoperative CT in the assessment of penetrating abdominal lesions. Between January 1, 2015 and January 1, 2022, 81 patients were hospitalized following penetrating abdominal trauma at the Army Training Hospitals of Sainte-Anne and Laveran. Fifty-one stable patients who had an abdominopelvic CT scan and thereafter underwent abdominal surgery (laparotomy or laparoscopy) were included. Radiological and surgical data were collected from the electronic record and compared by a descriptive analysis (calculation of the sensitivity, specificity, positive and negative predictive value of the CT for the detection of lesions of the various organs) and by a correlation of the CT findings with surgical findings using Kripendorff's alpha coefficient. The cohort was largely male (n=45; 88%), with injuries by knife wound in 62.7% of cases (n=32) and gunshot in 35.3% (n=18) of cases. The median age was 36years (25-47). The median index of severity score (ISS) was 17 (10-26). Excellent agreement between predicted and actual findings was obtained for solid organs (α=0.801) with high sensitivity and specificity (81.8% and 96.6%, respectively). The largest discrepancies were observed for the hollow organs (α=26.2%, sensitivity of 53.3% and specificity of 76.2%) and the diaphragm (α=67.3%, sensitivity 75%, specificity 92.3%). Surgical exploration was non-therapeutic for five patients (9.8%). The failure rate for non-operative treatment was 10% (n=1). CT detection of solid organ lesions in patients with penetrating abdominal wounds is excellent. However, the detection of hollow organ and diaphragmatic wounds remains a challenge with a risk of over- and underdiagnosis. Laparoscopic exploration should be able to fill in the gaps in the CT findings.

Comparison of diagnostic efficacy of dual-energy CT and ultrasound in gouty arthritis.

To explore the performance and effect of dual-energy computed tomography (CT) and ultrasound in the diagnosis of gouty arthritis and to provide a reference for the clinical diagnosis of gouty arthritis. A retrospective analysis of 76 patients with gouty arthritis admitted to the hospital from June 2020 to June 2022 was conducted. Patients were diagnosed with gouty arthritis using ultrasound and dual-energy CT technology. The accuracy of diagnosis by different imaging techniques was analyzed along with the imaging findings of ultrasound and dual-energy CT. Seventy-six patients, 60 men and 16 women, ranging in age from 20 to 77 years (mean age 50.8 ± 10.92 years), presented with uric acid levels of 254.1-720.05 μmol/L (mean 482.17 ± 105.06 μmol/L) and C-reactive protein levels ranging from 4.25 to 10.3 mg/L. The receiver operating characteristic curve showed that the area under the curve and specificity of serum uric acid were higher by dual-energy CT than those of ultrasound in the diagnosis of gouty arthritis. The dual-energy CT detection rate of tophi was significantly higher than the ultrasound detection rate (p < .05). For inflammatory effusion and synovial thickening, the ultrasound detection rates were significantly higher than the dual-energy CT detection rates (p < .05). Regarding soft-tissue edema, the detection rate of the two methods was not significantly different (p > .05). Compared with ultrasound, dual-energy CT has increased accuracy in the diagnosis of gouty arthritis.

A combination of computed tomography scan and ultrasound provides optimal detection of cervical lymph node metastasis in papillary thyroid carcinomas: A systematic review and meta-analysis.

Lymph node metastasis (LNM) in patients with papillary thyroid carcinoma (PTC) is common. This meta-analysis assesses the diagnostic accuracy of computed tomography (CT), ultrasound (US), and CT + US in detecting central and lateral LNM. A systematic review and meta-analysis was performed by searching PubMed, Embase, and Cochrane for studies published up to April 2022. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated. The area under the curve (AUC) for summary receiver operating curves (sROC) were compared. The study population included 7902 patients with a total of 15 014 lymph nodes. Twenty-four studies analyzed the sensitivity of the overall neck region in which dual CT + US imaging (55.9%) had greater sensitivities (p < 0.001) than either US (48.4%) or CT (50.4%) alone. The specificity of US alone (89.0%) was greater (p < 0.001) than CT alone (88.5%) or dual imaging (86.8%). The DOR for dual CT + US imaging was greatest (p < 0.001) at 11.134, while the AUCs of the three imaging modalities were similar (p > 0.05). Twenty-one studies analyzed the sensitivity of the central neck region in which both CT (45.8%) and CT + US imaging (43.4%) had greater sensitivities (p < 0.001) than US alone (35.3%). The specificity of all three modalities was higher than 85%. The DOR for CT (7.985) was greater than US alone (4.723, p < 0.001) or dual CT + US imaging (4.907, p = 0.015). The AUC of both CT + US (0.785) and CT alone (0.785) were significantly greater (p < 0.001) than US alone (0.685). Of the 19 studies that reported lateral LNM, CT + US imaging sensitivity (84.5%) was higher than CT alone (69.2%, p < 0.001) and US alone (79.7%, p = 0.038). The specificity of all imaging techniques was all greater than 80.0%. CT + US imaging DOR (35.573) was greater than CT (20.959, p = 0.024) and US (15.181, p < 0.001) individually. The AUC of independent imaging was high (CT: 0.863, US: 0.858) and improved significantly when combined (CT + US: 0.919, p = 0.024 and p < 0.001, respectively). We report an up-to-date analysis elucidating the diagnostic accuracy of LNM detection by either CT, US, or in combination. Our work suggests dual CT + US to be the best for overall detection of LNM and CT to be preferable in detecting central LNM. The use of either CT or US alone may detect lateral LNM with acceptable accuracy, yet dual imaging (CT + US) significantly improved detection rates.

High-resolution computed tomography angiography of the orbit using a photon-counting computed tomography scanner.

Recent introduction of photon counting detector (PCD) computed tomography (CT) scanners into clinical practice further improve CT angiography (CTA) depiction of orbital arterial vasculature compared to conventional energy integrating detector (EID) CT scanners. PCD-CTA of the orbit can provide a detailed arterial roadmap of the orbit which can de diagnostic on its own or serve as a helpful planning adjunct for both diagnostic and therapeutic catheter-based angiography of the orbit. For this review, EID and PCD-CT imaging was obtained in 28 volunteers. The volume CT dose index was closely matched. A dual-energy scanning protocol was used on EID-CT. An ultra-high-resolution (UHR) scan mode was used on PCD-CT. Images were reconstructed at 0.6 mm slice thickness using a closely matched medium-sharp standard resolution (SR) kernel. High-resolution (HR) images with the sharpest quantitative kernel were also reconstructed on PCD-CT at the thinnest slice thickness of 0.2 mm. A denoising algorithm was applied to the HR image series. The imaging description of the orbital vascular anatomy presented in this work was derived from these patients' PCD-CTA images in combination with review of the literature. We found that orbital arterial anatomy is much better depicted with PCD-CTA, and this work can serve primarily as an imaging atlas of the normal orbital vascular anatomy. With recent advances in technology, arterial anatomy of the orbit is much better depicted with PCD-CTA as opposed to EID-CTA. Current orbital PCD-CTA technology approaches the necessary resolution threshold for reliable evaluation of central retinal artery occlusion.

Three-dimensional reconstruction and morphometric analysis of mandible of Hamdani sheep: A computed tomography (CT) study

In this study, anatomical, morphometric and volumetric analyses of the mandible of Hamdani sheep were performed using computed tomography (CT) and three-dimensional (3D) software. For this purpose, 16 (eight males, eight females) Hamdani sheep heads were used. Images of these heads were taken on a 64-detector CT device applying 80 kV, 200 MA, 639 mGY, and 0.625 mm section thickness. Scan images of the mandible of each subject were converted into three-dimensional models using 3D software and reconstructed. Surface, volume and linear measurements (24) of the mandible were performed on the models. All the measurements were expressed as mean ± SD. The examinations determined that the mandible's volume and surface area values were more significant in males than females. Mandible length (GOC-ID) was 169.01±0.74 mm, and its height (GOV-CR) was 95.50±0.64 mm in males. In morphometric evaluations, statistically significant differences were observed between males and females in L2 (PC-ID), L6 (GOC-FMN), L14 (MTR-MH), L19(SI), Volume and Surface area measurement parameters (P&amp;lt;0.05). It is thought that the morphometric data obtained will be a reference in pathological conditions, taxonomy studies, and interventional surgical treatment applications to be performed on the site.