Multidetector Computed Tomography Research Articles

The role of computed tomography in diagnosis of patients with chest trauma

Purpose: Chest traumas are a significant cause of mortality and morbidity. The purpose of this article is to present the place of CT in the diagnosis of chest trauma patients. Methods and Materials: Multi detector computed tomography (MDCT) is considered to be the most effective imaging method in trauma patients. Its advantages include high speed and high geometric resolution at any plane. The method allows us to view large parts of the body with minimal motion artifacts and to create accurate multiplane reformations. One hundred and twelve patients are examined at the Emergency department. The injuries of the chest and intrathoracic organs are found. The research method is discussed by imaging diagnosticians and clinicians with a view to using the most informative diagnostic method in each individual case. Of course, informed consent is also taken from the patients. The MDCT machine are used predominantly in these patients. Results: One hundred and twelve patients are examined at the Emergency department in purpose to evaluate chest lesions. MDCT allows us to view diagnosis significantly more accurate procedure. The injuries of the chest and intrathoracic organs are found. In 56 (50%) of all 112 patients included in the study, fractures of the ribs are the most common traumas. Also fracture of the scapula, sternum, extra pleural hematomas, pneumothorax, hemothorax, pulmonary contusions, laceration of trachea and bronchi, rupture of esophagus, diaphragmatic rupture and injuries of blood vessels are established. Conclusion: We present our experience in imaging diagnosis and behavior in poly trauma patients in conditions of emergency. MDCT must be used as first necessary investigation a procedure which allows us to view diagnosis significantly more accurate than other imaging methods.

Can MDCT Enhancement Patterns Be Helpful in Differentiating Secretory from Non-Functional Adrenal Adenoma?

Background and Objectives: Primary adrenal tumors (AT) are a heterogeneous group of neoplasms due to their functional heterogeneity, which results in the diverse clinical presentation of these tumors. The purpose of this study was to examine cross-sectional imaging characteristics using multi-detector computed tomography (MDCT) to provide insight into the lesion characterization and functional status of these tumors. The radionuclide imaging using Technetium-99m radiolabeled hydrazinonicotinylacid-d-phenylalanyl1-tyrosine3-octreotide (99mTc-HYNIC-TOC), was also used in the diagnostic evaluation of these tumors. Materials and Methods: This cross-sectional study included 50 patients with confirmed diagnoses of AT (21 hormone-secreting and 29 non-functional) at the University Clinical Center, Kragujevac, Serbia, during the 2019-2022 year period. The morphological and dynamic characteristics using MDCT were performed, using qualitative, semi-quantitative, and quantitative analysis. Absolute washout (APW) and relative washout (RPW) values were also calculated. A semi-quantitative analysis of all visual findings with 99mTc-HYNIC-TOC was performed to compare the tumor to non-tumor tracer uptake. Results: A statistically significant difference was found in the MDCT values in the native phase (p < 0.05), the venous phase (p < 0.05), and the delayed phase (p < 0.001) to detect the existence of adrenal tumors. Most of these functional adrenocortical lesions (n = 44) can be differentiated using the delayed phase (p < 0.05), absolute percentage washout (APW) (p < 0.05), and relative percentage washout (RPW) (p < 0.001). Furthermore, 99mTc-HYNIC-TOC could have a high diagnostic yield to detect adrenal tumor existence (p < 0.001). There is a positive correlation between radionuclide imaging scan and APW to detect all AT (p < 0.01) and adrenocortical adenomas as well (p < 0.01). Conclusions: The results can be very helpful in a diagnostic algorithm to quickly and precisely diagnose the expansive processes of the adrenal glands, as well as to learn about the advantages and limitations of the mentioned imaging modalities.

Improving the impact of different input arteries on cerebral CT perfusion parameters and ischemic penumbra

This study aims to examine the impact of different input arteries on cerebral perfusion parameters and the volume of core infarction, ischemic area, and penumbra automatically measured by software in post-processing 256-slice CT brain perfusion images. Retrospective analysis was conducted on brain perfusion images of 58 patients who underwent 256-slice multidetector CT examination for cerebral infarction. Various input arteries, including bilateral internal carotid artery (ICA), bilateral middle cerebral artery (MCA), anterior cerebral artery (ACA), and basilar artery (BA), were selected for image processing and measurements. The volumes of core infarction, ischemic area, and penumbra were automatically calculated using software. Additionally, manual measurements were per-formed by experienced doctors. Perfusion parameters including cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to peak (TTP) were evaluated. The change of input artery resulted in a significant difference in CBF and MTT in the penumbra and normal brain tissue areas. However, no significant difference was observed in CBV, TTP, and perfusion parameters in the core infarct area. The volumes of core infarction acquired from different input arteries showed no significant difference. Nonetheless, significant differences were found in the volume of the ischemic area and the mismatched area. The selection of different input arteries affects CT cerebral perfusion parameter values and the automatic measurement of the ischemic area and penumbra by software. Thus, when performing post-processing of CT cerebral perfusion images, it is advisable to choose the thicker internal carotid artery on the healthy side as the input artery.

Rare Presentation of Myocardial Ischemia in a Patient with an Anomalous Right Coronary Artery

BACKGROUND: Coronary anomalies are coronary patterns that occur rarely in the general population. The most common type of these anomalies is the emergence of the right coronary artery (RCA) from the left coronary sinus, which in most patients is either asymptomatic or leads to sudden cardiac death (SCD). THE CASE: This case report presents the case of a 35-year-old male patient who had an inferior ST elevation myocardial infarction (STEMI) for which percutaneous coronary intervention was attempted and failed due to the patient going into cardiac arrest. The patient was subsequently managed medically in the cardiac intensive care unit and followed up outpatient with a cardiologist. The patient experienced symptoms of exertional angina and had a CT angiography of the heart and coronary vessels that identified an anomalous RCA emerging from the left coronary sinus. He was diagnosed with an anomalous RCA with malignant take-off from the left coronary sinus, and subsequent management was surgical with a coronary artery bypass graft (CABG) x1 using the right internal mammary artery (RIMA to RCA). Intraoperatively, the patient was found to have sclerosis of the RCA proximally for about 5cm. The patient did well post-operatively and had no symptoms of exertional angina upon outpatient follow up with both his cardiologist and cardiothoracic surgeon. CONCLUSION: Most cases of coronary anomalies have been found to be either completely asymptomatic or lead to SCD, especially in young patients, however very few cases in literature identified patients with this anomaly presenting with STEMI such as in this case. Another significant finding in this patient is sclerosis of the RCA, where although some articles propose that anomalous coronary arteries may be more susceptible to atherosclerosis, others conclude that there may be no association; concluding that factors such as intramural course, slit-like origin, and acute angle take-off might be more significantly associated. Moreover, patients with coronary anomalies rarely experience cardiac events solely due to their anomaly, such as with this patient. Finally, this patient’s significantly young age at 35 years old is significant given the mean age of patients undergoing CABG being 60.8 years in one cross-sectional study. Current management of symptomatic patients with these anomalies is under debate, with many patients undergoing CABG such as in this case, although one study shows no significant difference in mortality or 10-year survival with surgical intervention despite having higher surgical intervention rates. Percutaneous coronary intervention (PCI) of patients with coronary anomalies has been shown to be difficult or unsuccessful in most studies, although a few cases in literature were successful with tools such as multidetector CT (MDCT). Awareness of these anomalies and their possible presentation, risk factors, and radiologic findings is important especially given their potential for SCD. More research is needed to further elucidate the best treatment options and perhaps even improve the potential for non-invasive interventional techniques such as PCI.

The efficiency and safety of multidetector computed tomography-guided transseptal puncture during atrial fibrillation catheter ablation.

Transseptal puncture (TSP) is a crucial technique for catheter ablation of atrial fibrillation (AF). Although intracardiac echo (ICE) facilitates a safe and accurate TSP, it is not widely used in developing countries because of the expense. This study evaluated the efficiency and safety of a novel cardiac multidetector computed tomography (MDCT)-guided TSP during AF catheter ablation. The study consisted of two cohorts. In the index cohort, TSP procedure was performed under the guidance of ICE, and we recorded the angulation of right anterior oblique of X-ray projection. In the validation cohort, we compared the efficiency and safety of TSP guided by MDCT-calculated angulation with propensity-score-matched patients who underwent TSP guided by ICE. We included 50 patients in the index cohort, and the mean angles of interatrial septum (IAS) measured from MDCT and ICE were 34.8 ± 6.3 and 35.1 ± 6.5, respectively. In the validation cohort, 376 patients were enrolled in the MDCT-guided group and ICE-guided group. Both groups had 1 case of cardiac tamponade. The mean axial plane angle was 35.46 ± 6.17 degrees, which was not influenced by age, gender, BMI, and LA size, while a moderate positive linear correlation between EF and the axial plane angle (R 2 = 0.14, p = .006). Cardiac MDCT can provide a clear vision of IAS orientation, and provide the appropriate RAO angle and height for TSP. The efficiency and safety of our MDCT-guided TSP were comparable to ICE-guided TSP, which may serve as an alternative method for TSP with ICE unavailable.

2D antiscatter grid and scatter sampling based CBCT method for online dose calculations during CBCT guided radiation therapy of pelvis.

Online dose calculations before the delivery of radiation treatments have applications in dose delivery verification, online adaptation of treatment plans, and simulation-free treatment planning. While dose calculations by directly utilizing CBCT images are desired, dosimetric accuracy can be compromised due to relatively lower HU accuracy in CBCT images. In this work, we propose a novel CBCT imaging pipeline to enhance the accuracy of CBCT-based dose calculations in the pelvis region. Our approach aims to improve the HU accuracy in CBCT images, thereby improving the overall accuracy of CBCT-based dose calculations prior to radiation treatment delivery. An in-house developed quantitative CBCT pipeline was implemented to address the CBCT raw data contamination problem. The pipeline combines algorithmic data correction strategies and 2D antiscatter grid-based scatter rejection to achieve high CT number accuracy. To evaluate the effect of the quantitative CBCT pipeline on CBCT-based dose calculations, phantoms mimicking pelvis anatomy were scanned using a linac-mounted CBCT system, and a gold standard multidetector CT used for treatment planning (pCT). A total of 20 intensity-modulated treatment plans were generated for five targets, using 6 and 10 MV flattening filter-free beams, and utilizing small and large pelvis phantom images. For each treatment plan, four different dose calculations were performed using pCT images and three CBCT imaging configurations: quantitative CBCT, clinical CBCT protocol, and a high-performance 1D antiscatter grid (1D ASG). Subsequently, dosimetric accuracy was evaluated for both targets and organs at risk as a function of patient size, target location, beam energy, and CBCT imaging configuration. When compared to the gold-standard pCT, dosimetric errors in quantitative CBCT-based dose calculations were not significant across all phantom sizes, beam energies, and treatment sites. The largest error observed was 0.6% among all dose volume histogram metrics and evaluated dose calculations. In contrast, dosimetric errors reached up to 7% and 97% in clinical CBCT and high-performance ASG CBCT-based treatment plans, respectively. The largest dosimetric errors were observed in bony targets in the large phantom treated with 6 MV beams. The trends of dosimetric errors in organs at risk were similar to those observed in the targets. The proposed quantitative CBCT pipeline has the potential to provide comparable dose calculation accuracy to the gold-standard planning CT in photon radiation therapy for the abdomen and pelvis. These robust dose calculations could eliminate the need for density overrides in CBCT images and enable direct utilization of CBCT images for dose delivery monitoring or online treatment plan adaptations before the delivery of radiation treatments.

Serum elastase-1 predicts malignancy in intraductal papillary mucinous neoplasm of the pancreas

BackgroundThe indication for surgical resection of intraductal papillary mucinous neoplasms (IPMNs) is defined by imaging features, such as mural nodules. Although carbohydrate antigen (CA) 19-9 was selected as a parameter for worrisome features, no serum biomarkers were considered when deciding on surgical indications in the latest international consensus guideline. In this study, we assessed whether clinical factors, imaging findings, and serum biomarkers are useful in predicting malignant IPMNs. MethodsA total of 234 resected IPMN cases in Chiba University Hospital from July 2005 to December 2021 were retrospectively analyzed. ResultsAmong the 234 patients with resected IPMNs diagnosed by preoperative imaging, 117 were diagnosed with malignant pathologies (high-grade dysplasia and invasive IPMNs) according to the histological classification. In the multivariate analysis, cyst diameter ≥30 mm; p = 0.035), enhancing mural nodules on multidetector computed tomography (≥5 mm; p = 0.018), and high serum elastase-1 (≥230 ng/dl; p = 0.0007) were identified as independent malignant predictors, while CA19-9 was not. Furthermore, based on the receiver operator characteristic curve analyses, elastase-1 was superior to CA19-9 for predicting malignant IPMNs. Additionally, high serum elastase-1 levels (≥230 ng/dl; p = 0.0093) were identified as independent predictors of malignant IPMNs in patients without mural nodules on multidetector computed tomography (MDCT) in multivariate analysis. ConclusionThe serum elastase-1 level was found to be a potentially useful biomarker for predicting malignant IPMNs.

The Role of Cone-Beam Computed Tomography CT Extremity Arthrography in the Preoperative Assessment of Osteoarthritis.

Osteoarthritis (OA) is a prevalent disease and the leading cause of pain, disability, and quality of life deterioration. Our study sought to evaluate the image quality and dose of cone-beam computed tomography arthrography (CBCT-A) and compare them to digital radiography (DR) for OA diagnoses. Overall, 32 cases of CBCT-A and DR with OA met the inclusion criteria and were prospectively analyzed. The Kellgren and Lawrence classification (KLC) stage, sclerosis, osteophytes, erosions, and mean joint width (MJW) were compared between CBCT-A and DR. Image quality was excellent in all CBCT-A cases, with excellent inter-observer agreement. OA under-classification was noticed with DR for MJW (p = 0.02), osteophyte detection (<0.0001), and KLC (p < 0.0001). The Hounsfield Unit (HU) values obtained for the cone-beam computed tomography CBCT did not correspond to the values for multi-detector computed tomography (MDCT), with a greater mean deviation obtained with the MDCT HU for Modeled Based Iterative Reconstruction 1st (MBIR1) than for the 2nd generation (MBIR2). CBCT-A has been found to be more reliable for OA diagnosis than DR as revealed by our results using a three-point rating scale for the qualitative image analysis, with higher quality and an acceptable dose. Moreover, the use of this imaging technique permits the preoperative assessment of extremities in an OA diagnosis, with the upright position and bone microarchitecture analysis being two other advantages of CBCT-A.

Evaluation of multidetector CT Hounsfield unit measurements as a predictor of efficacy and complications in percutaneous vertebroplasty for osteoporotic vertebral compression fractures

IntroductionMore than 30 years after the initial experience of Galibert and Deramond with percutaneous vertebroplasty, the procedure has gone through countless refinements and clinical evaluations. Predictors for the success and failure of the procedure in the literature vary and are focused on the duration of complaints, type of fracture, presence of edema on MRI scans, etc. We propose using a quantitative method based on a standard CT examination of the thoracic or lumbar spine to assess the risks and potential success of performing vertebroplasty.Materials and methodsThis is a single-center prospective observational study on 139 patients treated with percutaneous vertebroplasty (pVPL) for a single symptomatic osteoporotic vertebral compression fracture (OVCF). We measured the levels of disability and pain preoperatively and again at the 3-, 6- and 12-month marks using the standardized VAS and ODI questionnaires. Every patient in the study was evaluated with postoperative multidetector CT (MDCT) to determine the presence, extent, and localization of vertebral cement leakage and to measure the adjacent vertebrae’s minimal and mean density in Hounsfield units (HUmin and HUmean, respectively).ResultsWe determined that a slight (r = −0.201) but statistically significant (p = 0.018) correlation existed between HU measurements taken from radiologically intact adjacent vertebrae and the procedure’s effect concerning the pain levels at the 3-month follow-up. This correlation failed to reach statistical significance at 12 months (p = 0.072). We found no statistically significant relationship between low vertebral cancellous bone density and cement leakage on postoperative scans (p = 0.6 for HUmin and p = 0.74 for HUmean).ConclusionWe have moderately strong data that show a negative correlation between the mean values of vertebral cancellous bone density in patients with OVCF and the effect of pVPL in reducing pain. Lower bone densities, measured this way, showed no increased risk of cement leakage.

Pro-Inflammatory Biomarkers and Progression of Atherosclerosis in Patients with Myocardial Infarction with Non-Obstructive Coronary Artery Disease: 1-Year Follow-Up.

Samples of peripheral venous blood were collected upon admission and on days 2, 4, and 7 of hospitalization and after 1 year. An extended multiplex analysis was performed in blood serum. Multidetector-computed tomography coronary angiography was performed on day 7 and 1 year after acute myocardial infarction to assess the progression of atherosclerosis. The level of high-sensitive C-reactive protein (hsCRP) was elevated upon admission in MINOCA patients compared to MI-CAD patients (p = 0.05), but it was comparable in two groups at other time points and did not exceed the reference range after 1 year. Despite comparable levels of cytokines CXCL-6, LIGHT, CCL-8, and endocan-1 in patients in both groups, MINOCA patients had a greater increase in pro-inflammatory cytokines PlGF, oncostatin M, IL-20, and CCL-15 sVCAM-1 in the early post-infarction period and in CCL-21, sVCAM-1, oncostatin M, and PlGF after 1 year. We observed significant differences in the dynamics of the following biomarkers between patients with MI-CAD and MINOCA: the dynamics of concentrations of CCL21 (p = 0.002), LIGHT (p = 0.03), and endocan-1 (p = 0.03) after 1 year compared to day 1 in MI-CAD and MINOCA patients was opposite, while the dynamics of CXCL6 (p = 0.04) and endocan-1 (p = 0.02) differed between groups when evaluated after 1 year compared to day 7 of the early post-infarction period. In the MINOCA group, factors associated with atherosclerosis progression were concentrations of sVCAM-1 and CCL-21, while in the MI-CAD group, concentrations of CCL-8 and CXCL6 were the main determinants of atherosclerosis progression. This small study showed that MINOCA and MI-CAD patients exhibited differences in a pro-inflammatory biomarker profile in the early post-infarction period and after 1-year follow-up, which implies distinct inflammatory pathways involved in atherogenesis during MINOCA. The key factors that were associated with atherosclerosis progression in MINOCA patients are sVCAM-1 and CCL-21, which may suggest a complex genesis of atherosclerosis progression due to structurally altered plaques and changes in the microcirculatory bed. In MI-CAD patients, CCL-8 and CXCL-6 were the key biomarkers associated with atherosclerosis progression. Further large-scale studies are required to confirm our data.

Assessing left atrial intramyocardial fat infiltration from computerized tomography angiography in patients with atrial fibrillation.

Epicardial adipose tissue might promote atrial fibrillation (AF) in several ways, including infiltrating the underlying atrial myocardium. However, the role of this potential mechanism has been poorly investigated. The aim of this study is to evaluate the presence of left atrial (LA) infiltrated adipose tissue (inFAT) by analysing multi-detector computer tomography (MDCT)-derived three-dimensional (3D) fat infiltration maps and to compare the extent of LA inFAT between patients without AF history, with paroxysmal, and with persistent AF. Sixty consecutive patients with AF diagnosis (30 persistent and 30 paroxysmal) were enrolled and compared with 20 age-matched control; MDCT-derived images were post-processed to obtain 3D LA inFAT maps for all patients. Volume (mL) and mean signal intensities [(Hounsfield Units (HU)] of inFAT (HU -194; -5), dense inFAT (HU -194; -50), and fat-myocardial admixture (HU -50; -5) were automatically computed by the software. inFAT volume was significantly different across the three groups (P = 0.009), with post-hoc pairwise comparisons showing a significant increase in inFAT volume in persistent AF compared to controls (P = 0.006). Dense inFAT retained a significant difference also after correcting for body mass index (P = 0.028). In addition, more negative inFAT radiodensity values were found in AF patients. Regional distribution analysis showed a significantly higher regional distribution of LA inFAT at left and right superior pulmonary vein antra in AF patients. Persistent forms of AF are associated with greater degree of LA intramyocardial adipose infiltration, independently of body mass index. Compared to controls, AF patients present higher LA inFAT volume at left and right superior pulmonary vein antra.

Pulmonary Vein Stenosis After Catheter Ablation of Atrial Fibrillation Using a Cryoballoon, Hot Balloon, or Laser Balloon.

Pulmonary vein stenosis (PVS) after PV isolation (PVI) for atrial fibrillation (AF) is a severe complication that requires angioplasty. This study aimed to compare the reduction of the cross-sectional PV area (PVA) and the incidence of PVS after cryoballoon (CB)-PVI, hot balloon (HB)-PVI, or laser balloon (LB)-PVI. A total of 320 patients who underwent an initial catheter ablation procedure for AF using a CB, HB, or LB in 2 hospitals were included. They underwent contrast-enhanced multidetector CT before and 3 months after the procedure. In all 4 PVs, the reduction in PVA was more significant in the LB group than in the CB or HB groups, respectively. Moderate (50-75%) and severe (>75%) PVS were observed in 5.3% and 0.5% of the PVs, respectively. Although moderate PVS was more frequently observed in the LB group than in the CB or HB groups (8.2%, 3.8%, and 5.0%; P=0.03), the incidence of severe PVS was similar in the LB, CB, and HB groups (0.3%, 0.5%, and 1.0%; P=0.46). Symptomatic PVS requiring intervention occurred in 1 (0.3%) patient. Although the reduction in cross-sectional PVA and the incidence of moderate PVS after LB-PVI was more significant than after CB-PVI or HB-PVI, it rarely led to severe PVS. Symptomatic PVS requiring intervention was rare after the balloon ablation of AF.

Flat panel CT versus multidetector CT in skull base imaging: are there differences in image quality?

BackgroundPurpose of this study was to compare image quality of the skull base in standard 20s protocol flat panel computed tomography (FPCT) with the new time and dose improved 10s protocol as well as with 128 slice multidetector computed tomography (MDCT).Methods10 whole skull preparations were scanned with either 128 slice MDCT(SOMATOM Definition AS+, Siemens, Erlangen) or FPCT (AXIOM-Artis, Siemens, Erlangen) using 10s or 20s protocol.ResultsFPCT provides significantly better image quality and improved delimitation of clinically relevant structures in the anterior, temporal and posterior skull base compared to 128 slice MDCT. The 20s FPCT protocol yielded best delimitability of evaluated skull base structures. However, the shorter, dose saving 10s FPCT protocol was still significantly superior to 128 slice MDCT regarding delimitability of skull base structures and additionally showed no significant inferiority compared with the 20s FPCT protocol.ConclusionsThe 10s FPCT protocol yields a significantly better image quality at a comparable radiation dose exposure in imaging skull base structures compared to MDCT.Trial registration371/2017BO2.

HPB P05 PET-CT in the staging of potentially resectable pancreatic cancer

Abstract Background Pancreatic adenocarcinoma (PDAC) presents a significant global health challenge particularly as it is generally diagnosed at an advanced stage. Although cross-sectional imaging techniques including multidetector CT (MDCT) are familiar and ubiquitously used the role and value of PET-CT scans in PDAC management remains unclear. Methods This six-year study analysed patients who underwent PET-CT scans for suspected PDAC. Demographics, cross-sectional imaging and PET-CT results, management decisions, and histology were collected together with rates of operation with curative intent and the time interval between scans and surgical intervention. Results Of 161 patients, 110 were operable, but 51 weren't. Among operable ones, 20 had extra-pancreatic lesions; 90 didn't. Without extra-pancreatic lesions, 68 underwent surgery, 12 unfit, and 10 had benign conditions. Among those explored, 9 had unconfirmed suspected metastasis. Of all explored, 48 had successful resection; 20 had precluding diseases. In the subset with extra-pancreatic lesions, 4 were inoperable due to confirmed metastasis. The remaining 16 explored had equivocal or unrelated lesions; 9 were resectable, 7 weren't. PET-CT scans impacted patient management in 8% of cases. Conclusions PET-CT scans play a crucial role in the management of suspected PDAC, but routine use may not be justified. Further research is needed to identify the subset of patients who benefit most. Clear guidelines for PET scan utilization in clinical practice are required to optimize the role in PDAC management.

About different localization of hypoattenuated lesions following transcatheter aortic valve replacement

BackgroundSubclinical leaflet thrombosis is diagnosed using multidetector computed tomography (MDCT) and is characterised 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 leaflet and extra-leaflet components such as the valve skirt. Little is known about extra-leaflet hypoattenuated lesion localisation, including that at the anatomical sinus level. Thus, the main aim of this study was to describe leaflet and extra-leaflet (anatomic sinus and subvalvular level) hypoattenuated lesions following transcatheter aortic valve replacement with a self-expandable prosthesis. As a secondary aim, we sought to investigate predictors of hypoattenuated lesions. MethodsFifty patients underwent MDCT at the follow-up. ResultsAt a follow-up of 12 months, hypoattenuated leaflet lesions with mild to severe restricted movement were detected in eight individuals (16%), anatomic sinus lesions were identified in nine patients (18%), with higher prevalence in the non-coronary sinus (16%), and subvalvular lesions with variable extension toward the valve inflow were diagnosed in eight patients (16%). In 4 patients (8%) the anatomic sinus thrombus was ‘in overlap’ with leaflet thrombus; in 3 patients (6%) was in continuity with 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)). ConclusionsThis study demonstrated that hypoattenuated lesions could be identified not only at the leaflet but also at the subvalvular and anatomic sinus levels. The clinical relevance of such lesions remains unclear.

Deep learning in computed tomography super resolution using multi-modality data training.

One of the limitations in leveraging the potential of artificial intelligence in X-ray imaging is the limited availability of annotated training data. As X-ray and CT shares similar imaging physics, one could achieve cross-domain data sharing, so to generate labeled synthetic X-ray images from annotated CT volumes as digitally reconstructed radiographs (DRRs). To account for the lower resolution of CT and the CT-generated DRRs as compared to the real X-ray images, we propose the use of super-resolution (SR) techniques to enhance the CT resolution before DRRgeneration. As spatial resolution can be defined by the modulation transfer function kernel in CT physics, we propose to train a SR network using paired low-resolution (LR) and high-resolution (HR) images by varying the kernel's shape and cutoff frequency. This is different to previous deep learning-based SR techniques on RGB and medical images which focused on refining the sampling grid. Instead of generating LR images by bicubic interpolation, we aim to create realistic multi-detector CT (MDCT) like LR images from HR cone-beam CT (CBCT)scans. We propose and evaluate the use of a SR U-Net for the mapping between LR and HR CBCT image slices. We reconstructed paired LR and HR training volumes from the same CT scans with small in-plane sampling grid size of . We used the residual U-Net architecture to train two models. SRUN : trained with kernel-based LR images, and SRUN : trained with bicubic downsampled data as baseline. Both models are trained on one CBCT dataset (n = 13 391). The performance of both models was then evaluated on unseen kernel-based and interpolation-based LR CBCT images (n = 10 950), and also on MDCT images (n = 1392). Five-fold cross validation and ablation study were performed to find the optimal hyperparameters. Both SRUN and SRUN models show significant improvements (p-value 0.05) in mean absolute error (MAE), peak signal-to-noise ratio (PSNR) and structural similarity index measures (SSIMs) on unseen CBCT images. Also, the improvement percentages in MAE, PSNR, and SSIM by SRUN is larger than SRUN . For SRUN , MAE is reduced by 14%, and PSNR and SSIMs increased by 6 and 8%, respectively. To conclude, SRUN outperforms SRUN , which the former generates sharper images when tested with kernel-based LR CBCT images as well as cross-modality LR MDCTdata. Our proposed method showed better performance than the baseline interpolation approach on unseen LR CBCT. We showed that the frequency behavior of the used data is important for learning the SR features. Additionally, we showed cross-modality resolution improvements to LR MDCT images. Our approach is, therefore, a first and essential step in enabling realistic high spatial resolution CT-generated DRRs for deep learningtraining.

Gender differences in association between expiratory dynamic airway collapse and severity of obstructive sleep apnea

ObjectivesRepetitive unbalances and tensions generated by inspiratory efforts against an obstructive upper airway during sleep predispose the development of expiratory central airway collapse. In addition, structures of the upper airway between men and women have differences and could be the reasons for differences in obstructive sleep apnea (OSA) prevalence between genders. The present study aimed to evaluate the association between parameters of expiratory dynamic tracheal collapse measured using chest multidetector CT and objectively measured OSA severity between men and women.Materials and methodsA total of 901 participants who underwent chest CT and overnight in-home polysomnography from the Korean Genome and Epidemiology Study were cross-sectionally analyzed (women: 46.2%). The participants were divided into three groups based on OSA severity by apnea–hypopnea index (AHI). Multivariate linear regression analysis was performed to determine the effects of central airway collapse after adjustment for cardiovascular-related covariates.ResultsIn a multivariate analysis, percentages of expiratory lumen structure reductions involving area, diameter, and perimeter were associated with AHI (all p values < 0.05) and with OSA severity (moderate-to-severe OSA than no OSA: β = 3.30%, p = 0.03; β = 2.05%, p = 0.02; β = 1.97%, p = 0.02, respectively) in women, whereas men had only a greater percentage of expiratory wall thickness reduction in moderate-to-severe OSA than no OSA (β = 0.72%, p = 0.003). In addition, women with both mild OSA and moderate-to-severe OSA had higher expiratory tracheal collapse than men without OSA, and a moderate effect of sex was observed (p for interaction = 0.007).ConclusionThe expiratory dynamic tracheal collapse was independently associated with severity of OSA in women than in men.Clinical relevance statementDifferences of pharyngeal structures and inherent features of airways by genders may affect the dissimilarities in vulnerability to sleep apnea between men and women.Key Points• The expiratory dynamic tracheal collapse was independently associated with severity of OSA in women than in men.• Women with over mild OSA had higher expiratory tracheal collapse than men without OSA, and moderate effect of sex was observed.• Structural differences of airway may affect differences in susceptibility of sleep apnea between genders.

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

Three-Dimensional Segmentation Assisted with Clustering Analysis for Surface and Volume Measurements of Equine Incisor in Multidetector Computed Tomography Data Sets.

Dental diagnostic imaging has progressed towards the use of advanced technologies such as 3D image processing. Since multidetector computed tomography (CT) is widely available in equine clinics, CT-based anatomical 3D models, segmentations, and measurements have become clinically applicable. This study aimed to use a 3D segmentation of CT images and volumetric measurements to investigate differences in the surface area and volume of equine incisors. The 3D Slicer was used to segment single incisors of 50 horses' heads and to extract volumetric features. Axial vertical symmetry, but not horizontal, of the incisors was evidenced. The surface area and volume differed significantly between temporary and permanent incisors, allowing for easy eruption-related clustering of the CT-based 3D images with an accuracy of >0.75. The volumetric features differed partially between center, intermediate, and corner incisors, allowing for moderate location-related clustering with an accuracy of >0.69. The volumetric features of mandibular incisors' equine odontoclastic tooth resorption and hypercementosis (EOTRH) degrees were more than those for maxillary incisors; thus, the accuracy of EOTRH degree-related clustering was >0.72 for the mandibula and >0.33 for the maxilla. The CT-based 3D images of equine incisors can be successfully segmented using the routinely achieved multidetector CT data sets and the proposed data-processing approaches.

Genotoxic and Cytotoxic Effects of Cone Beam Computed Tomography and Multidetector Computed Tomography on Exfoliated Buccal Epithelial Cells.

Cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) are frequently used in dental and maxillofacial problems. This study aimed to assess the genotoxicity and cytotoxicity effects of CBCT and MDCT radiographies on exfoliated buccal epithelial cells during dental examinations. This prospective experimental study was conducted at Babol University of Medical Sciences (Babol, Iran) from March 2021 to April 2021. Buccal mucosa smears were collected bilaterally pre-exposure and 12 days after CBCT or MDCT examinations. To compare the frequency of micronuclei and other cytotoxic cellular changes such as pyknosis, karyolysis, and karyorrhexis, the paired sample t test and Wilcoxon test were used. In addition, independent sample t test, Mann-Whitney, and Chi square tests were used to investigate the differences between the imaging methods and between men and women. All statistical analyses were performed using the SPSS software, and P≤0.05 was considered statistically significant. The current study included 60 adult patients (30 patients in each group), ranging in age from 21 to 50 years. The micronuclei and the other cytotoxic cellular changes increased significantly after CBCT and MDCT radiographic examinations on the 12th day compared to the pre-exposure results (P<0.001). MDCT had statistically higher cytotoxic and genotoxic effects than CBCT (9.4%, 23.1%, and 40% higher values in micronucleus frequency, the mean frequency of micronuclei, and other cytotoxic changes, respectively). There were no significant differences between men and women in the two examination methods (P=0.46 and P=0.49, respectively). Dental examinations with CBCT and MDCT can increase cytotoxicity and chromosomal damage in both men and women. Due to its lower radiation toxicities, CBCT can be recommended as an alternative to MDCT for dental examinations.