Deep learning image reconstruction generates thinner slice iodine maps with improved image quality to increase diagnostic acceptance and lesion conspicuity: a prospective study on abdominal dual-energy CT.

BACKGROUND: To assess the improvement of image quality and diagnostic acceptance of thinner slice iodine maps enabled by deep learning image reconstruction (DLIR) in abdominal dual-energy CT (DECT). METHODS: This study prospectively included 104 participants with 136 lesions. Four series of iodine maps were generated based on portal-venous scans of contrast-enhanced abdominal DECT: 5-mm and 1.25-mm using adaptive statistical iterative reconstruction-V (Asir-V) with 50% blending (AV-50), and 1.25-mm using DLIR with medium (DLIR-M), and high strength (DLIR-H). The iodine concentrations (IC) and their standard deviations of nine anatomical sites were measured, and the corresponding coefficient of variations (CV) were calculated. Noise-power-spectrum (NPS) and edge-rise-slope (ERS) were measured. Five radiologists rated image quality in terms of image noise, contrast, sharpness, texture, and small structure visibility, and evaluated overall diagnostic acceptability of images and lesion conspicuity. RESULTS: The four reconstructions maintained the IC values unchanged in nine anatomical sites (all p > 0.999). Compared to 1.25-mm AV-50, 1.25-mm DLIR-M and DLIR-H significantly reduced CV values (all p < 0.001) and presented lower noise and noise peak (both p < 0.001). Compared to 5-mm AV-50, 1.25-mm images had higher ERS (all p < 0.001). The difference of the peak and average spatial frequency among the four reconstructions was relatively small but statistically significant (both p < 0.001). The 1.25-mm DLIR-M images were rated higher than the 5-mm and 1.25-mm AV-50 images for diagnostic acceptability and lesion conspicuity (all P < 0.001). CONCLUSIONS: DLIR may facilitate the thinner slice thickness iodine maps in abdominal DECT for improvement of image quality, diagnostic acceptability, and lesion conspicuity.

Assessment of Arterial Involvement in Pancreatic Cancer: Utility of Reconstructed CT Images Perpendicular to Artery.

The purpose of this study was to investigate the utility of reconstructed CT images perpendicular to the artery for assessing arterial involvement from pancreatic cancer and compare the interobserver variability between it and the current diagnostic imaging method. This retrospective study included patients with pancreatic cancer in the pancreatic body or tail who underwent preoperative pancreatic protocol CT and distal pancreatectomy. Five radiologists used axial and coronal CT images (current method) and perpendicular reconstructed CT images (proposed method) to determine if the degree of solid soft-tissue contact with the splenic artery was ≤180° or >180°. The generalized estimating equations were used to compare the diagnostic performance of solid soft-tissue contact >180° between the current and proposed methods. Fleiss' ĸ statistics were used to assess interobserver variability. The sensitivity and negative predictive value for diagnosing solid soft-tissue contact >180° were higher (p < 0.001 for each) and the specificity (p = 0.003) and positive predictive value (p = 0.003) were lower in the proposed method than the current method. Interobserver variability was improved in the proposed method compared with the current method (ĸ = 0.87 vs. 0.67). Reconstructed CT images perpendicular to the artery showed higher sensitivity and negative predictive value for diagnosing solid soft-tissue contact >180° than the current method and demonstrated improved interobserver variability.

Diagnostic Challenges in Aortic Stenosis.

Aortic stenosis (AS) is the most prevalent degenerative valvular disease in western countries. Transthoracic echocardiography (TTE) is considered, nowadays, to be the main imaging technique for the work-up of AS due to high availability, safety, low cost, and excellent capacity to evaluate aortic valve (AV) morphology and function. Despite the diagnosis of AS being considered straightforward for a very long time, based on high gradients and reduced aortic valve area (AVA), many patients with AS represent a real dilemma for cardiologist. On the one hand, the acoustic window may be inadequate and the TTE limited in some cases. On the other hand, a growing body of evidence shows that patients with low gradients (due to systolic dysfunction, concentric hypertrophy or coexistence of another valve disease such as mitral stenosis or regurgitation) may develop severe AS (low-flow low-gradient severe AS) with a similar or even worse prognosis. The use of complementary imaging techniques such as transesophageal echocardiography (TEE), multidetector computed tomography (MDTC), or cardiac magnetic resonance (CMR) plays a key role in such scenarios. The aim of this review is to summarize the diagnostic challenges associated with patients with AS and the advantages of a comprehensive multimodality cardiac imaging (MCI) approach to reach a precise grading of the disease, a crucial factor to warrant an adequate management of patients.

Introducing AEM-RADS: A novel reporting and data system for abdominal emergencies.

PURPOSE: The Reporting and Data System (RADS) has proven successful in various medical settings, but a standardized reporting system for abdominal emergencies is lacking. In this study, the Abdominal Emergency Reporting and Data System (AEM-RADS) for urgent findings on abdominal CT scans is introduced to address the need for consistency in emergency radiology. METHODS: In this prospective observational study, conducted over a six-month period, the urgency of abdominal CT scans was assessed using the proposed AEM-RADS scoring system. The committee developed a scale ranging from AEM-RADS 1 (normal) to AEM-RADS 5 (urgent disease). Interobserver agreement between two observers with different experience was evaluated, and robust AEM-RADS reference values were established by radiologists who were not observers. Statistical analysis used mean, standard deviations and Kendall's tau analysis for interobserver agreement. RESULTS: Among 2656 patients who underwent CT for abdominal emergencies, the AEM-RADS distribution was 17.50% AEM-RADS 1, 28.57% AEM-RADS 2, 7.22% AEM-RADS 3, 35.61% AEM-RADS 4, and 11.06% AEM-RADS 5. Interobserver agreement was high, especially for urgent and emergent cases (p < 0.0001). Notable discrepancies were observed in AEM-RADS categories 2C-D and 3B-C, emphasizing the influence of radiologists' experience on interpretation. However, the interobserver agreement for both AEM-RADS 2C-D and 3B-C were statistically significant (p < 0.001). CONCLUSIONS: AEM-RADS showed promising reliability, particularly in identifying urgent and emergent cases. Despite some inter-observer discrepancies, the system showed potential for standardized emergency workups. AEM-RADS could significantly enhance diagnostic accuracy in abdominal emergencies and provide a structured framework for shared decision-making between clinicians and radiologists.0.

Variation of computed tomography-derived extracellular volume fraction and the impact of protocol parameters: A systematic review and meta-analysis.

BACKGROUND: Cardiac computed tomography quantification of extracellular volume fraction (CT-ECV) is an emerging biomarker of myocardial fibrosis which has demonstrated high reproducibility, diagnostic and prognostic utility. However, there has been wide variation in the CT-ECV protocol in the literature and useful disease cut-offs are yet to be established. The objectives of this meta-analysis were to describe mean CT-ECV estimates and to estimate the effect of CT-ECV protocol parameters on between-study variation. METHODS: We conducted a meta-analysis of studies assessing CT-ECV in healthy and diseased participants. We used meta-analytic methods to pool estimates of CT-ECV and performed meta-regression to identify the contribution of protocol parameters to CT-ECV heterogeneity. RESULTS: Thirteen studies had a total of 248 healthy participants who underwent CT-ECV assessment. Studies of healthy participants had high variation in CT-ECV protocol parameters. The pooled estimate of CT-ECV in healthy participants was 27.6% (95%CI 25.7%-29.4%) with significant heterogeneity (I2 â€‹= â€‹93%) compared to 50.2% (95%CI 46.2%-54.2%) in amyloidosis, 31.2% (28.5%-33.8%) in severe aortic stenosis and 36.9% (31.6%-42.3%) in non-ischaemic dilated cardiomyopathies. Meta-regression revealed that CT protocol parameters account for approximately 25% of the heterogeneity in CT-ECV estimates. CONCLUSION: CT-ECV estimates for healthy individuals vary widely in the literature and there is significant overlap with estimates in cardiac disease. One quarter of this heterogeneity is explained by differences in CT-ECV protocol parameters. Standardization of CT-ECV protocols is necessary for widespread implementation of CT-ECV assessment for diagnosis and prognosis.

CT Evaluation of Long-Term Changes in Common Bile Duct Diameter after Cholecystectomy.

Purpose: The present study aimed to investigate the frequency and extent of compensatory common bile duct (CBD) dilatation after cholecystectomy, assess the time between cholecystectomy and CBD dilatation, and identify potentially useful CT findings suggestive of obstructive CBD dilatation. Materials and Methods: This retrospective study included 121 patients without biliary obstruction who underwent multiple CT scans before and after cholecystectomy at a single center between 2009 and 2011. The maximum short-axis diameters of the CBD and intrahepatic duct (IHD) were measured on each CT scan. In addition, the clinical and CT findings of 11 patients who were initially excluded from the study because of CBD stones or periampullary tumors were examined to identify distinguishing features between obstructive and non-obstructive CBD dilatation after cholecystectomy. Results: The mean (standard deviation) short-axis maximum CBD diameter of 121 patients was 5.6 (± 1.9) mm in the axial plane before cholecystectomy but increased to 7.9 (± 2.6) mm after cholecystectomy (p < 0.001). Of the 106 patients with a pre-cholecystectomy axial CBD diameter of < 8 mm, 39 (36.8%) showed CBD dilatation of ≥ 8 mm after cholecystectomy. Six of the 17 patients with longterm (> 2 years) serial follow-up CT scans (35.3%) eventually showed a significant (> 1.5-fold) increase in the axial CBD diameter, all within two years after cholecystectomy. Of the 121 patients without obstruction or related symptoms, only one patient (0.1%) showed IHD dilatation > 3 mm after cholecystectomy. In contrast, all 11 patients with CBD obstruction had abdominal pain and abnormal laboratory indices, and 81.8% (9/11) had significant dilatation of the IHD and CBD. Conclusion: Compensatory non-obstructive CBD dilatation commonly occurs after cholecystectomy to a similar extent as obstructive dilatation. However, the presence of relevant symptoms, significant IHD dilatation, or further CBD dilatation 2-3 years after cholecystectomy should raise suspicion of CBD obstruction.

Super-resolution deep-learning reconstruction for cardiac CT: impact of radiation dose and focal spot size on task-based image quality.

This study aimed to evaluate the impact of radiation dose and focal spot size on the image quality of super-resolution deep-learning reconstruction (SR-DLR) in comparison with iterative reconstruction (IR) and normal-resolution DLR (NR-DLR) algorithms for cardiac CT. Catphan-700 phantom was scanned on a 320-row scanner at six radiation doses (small and large focal spots at 1.4-4.3 and 5.8-8.8 mGy, respectively). Images were reconstructed using hybrid-IR, model-based-IR, NR-DLR, and SR-DLR algorithms. Noise properties were evaluated through plotting noise power spectrum (NPS). Spatial resolution was quantified with task-based transfer function (TTF); Polystyrene, Delrin, and Bone-50% inserts were used for low-, intermediate, and high-contrast spatial resolution. The detectability index (d') was calculated. Image noise, noise texture, edge sharpness of low- and intermediate-contrast objects, delineation of fine high-contrast objects, and overall quality of four reconstructions were visually ranked. Results indicated that among four reconstructions, SR-DLR yielded the lowest noise magnitude and NPS peak, as well as the highest average NPS frequency, TTF50%, d' values, and visual rank at each radiation dose. For all reconstructions, the intermediate- to high-contrast spatial resolution was maximized at 4.3 mGy, while the lowest noise magnitude and highest d' were attained at 8.8 mGy. SR-DLR at 4.3 mGy exhibited superior noise performance, intermediate- to high-contrast spatial resolution, d' values, and visual rank compared to the other reconstructions at 8.8 mGy. Therefore, SR-DLR may yield superior diagnostic image quality and facilitate radiation dose reduction compared to the other reconstructions, particularly when combined with small focal spot scanning.

Image-Guided Minimally Invasive Treatment Options for Degenerative Lumbar Spine Disease: A Practical Overview of Current Possibilities.

Lumbar back pain is one of the main causes of disability around the world. Most patients will complain of back pain at least once in their lifetime. The degenerative spine is considered the main cause and is extremely common in the elderly population. Consequently, treatment-related costs are a major burden to the healthcare system in developed and undeveloped countries. After the failure of conservative treatments or to avoid daily chronic drug intake, invasive treatments should be suggested. In a world where many patients reject surgery and prefer minimally invasive procedures, interventional radiology is pivotal in pain management and could represent a bridge between medical therapy and surgical treatment. We herein report the different image-guided procedures that can be used to manage degenerative spine-related low back pain. Particularly, we will focus on indications, different techniques, and treatment outcomes reported in the literature. This literature review focuses on the different minimally invasive percutaneous treatments currently available, underlining the central role of radiologists having the capability to use high-end imaging technology for diagnosis and subsequent treatment, allowing a global approach, reducing unnecessary surgeries and prolonged pain-reliever drug intake with their consequent related complications, improving patients' quality of life, and reducing the economic burden.

Assessment of Biological Damage Induced during Multidetector Computed Tomography (MDCT) Examination.

Computed tomography (CT) is known for its non-invasiveness, fast procedure, and also for providing detailed diagnostic information to physicians. It also utilises low-dose-rate ionising radiation (X-rays) as a source for imaging. Multidetector computed tomography (MDCT) is an advanced system that uses iodinated contrast media for more accurate diagnostic results. Studies suggest using these contrasts will lead to greater radiation adsorption with significant DNA damage. No studies have been taken comparing the physical dose with the biological effect. The present study sheds light on the same by assessing the biological effect of CT with and without contrast intervention. The present study is timebound; thus, 21 participants attending for CT thorax and abdomen with no history of any cancer were included. The same participants underwent both pre-contrast and post-contrast studies. The blood sample was taken before the procedure and used as a control. Physical parameters like DLP and CTDI obtained from the instrument were compared with the MN frequency obtained (CBMN Assay). The study showed a significant increase (p-value < 0.05) in the Physical and MN frequency in the Post-Contrast group compared to the pre-contrast group. Although a positive correlation was observed between pre and post-contrast groups, the results were not found to be statistically significant (p-value < 0.05). The study confirms increased physical dose and MN frequency upon contrast intervention. This study recommends the judicial use of MDCT in disease diagnostics.

Role of clinical and multidetector computed tomography (MDCT) features in the prediction of patients with intestinal lipoma developing intussusception.

Background: Intestinal lipoma is considered the most common benign tumor that causes intussusception. This retrospective case-control study aimed to present the clinical and multidetector computed tomography (MDCT) features between intestinal lipomas with and without intussusception and examine risk factors that predict intussusception caused by intestinal lipomas. Methods: We retrospectively analyzed 281 adult patients diagnosed with intestinal lipoma by radiologists using whole-abdominal MDCT between January 2015 and August 2022. Patients were divided into adult intussusception (AI) and non-AI groups based on MDCT images. Univariate logistic regression was performed to identify risk factors for intestinal lipoma-induced intussusception. Results: A total of 281 patients with intestinal lipomas were included in the study, with an average age of 68.0±11.3 years, and the male to female ratio was about 1:1.4. Among them, 24 patients developed lipoma-induced intussusception. Patients in the AI group presented with more abdominal pain (70.8% vs. 47.1%, P=0.03), nausea/vomiting (37.5% vs. 14.8%, P=0.009), hematochezia/melena (29.2% vs. 11.3%, P=0.02), and abdominal tenderness (66.7% vs. 24.9%, P<0.001). Lipomas were more common in the small bowel (224/281, 79.7%) than the large bowel (57/281, 20.3%). Lipomas in the AI group showed more heterogeneous hypodensity (41.7% vs. 15.6%, P=0.004), longer length (median, 2.2 vs. 1.2 cm, P<0.001), and larger volume (median, 4.1 vs. 0.6 cm3, P<0.001). In the univariate logistic regression, lipoma density [odds ratio (OR) =3.875, 95% confidence interval (CI): 1.609-9.331, P=0.003] and lipoma length (OR =3.216, 95% CI: 1.977-5.231, P<0.001) were risk factors for intestinal lipoma-induced intussusception. Conclusions: More patients in the AI group have digestive tract symptoms than those in the non-AI group. Lipoma density and length are risk factors for intussusception in patients with intestinal lipoma. In addition, the common site of intestinal lipoma may have changed from the colon to the small intestine.

Detection of malignant lesions in cytologically indeterminate thyroid nodules using a dual-layer spectral detector CT-clinical nomogram.

Purpose: To evaluate the capability of dual-layer detector spectral CT (DLCT) quantitative parameters in conjunction with clinical variables to detect malignant lesions in cytologically indeterminate thyroid nodules (TNs). Materials and methods: Data from 107 patients with cytologically indeterminate TNs who underwent DLCT scans were retrospectively reviewed and randomly divided into training and validation sets (7:3 ratio). DLCT quantitative parameters (iodine concentration (IC), NICP (IC nodule/IC thyroid parenchyma), NICA (IC nodule/IC ipsilateral carotid artery), attenuation on the slope of spectral HU curve and effective atomic number), along with clinical variables, were compared between benign and malignant cohorts through univariate analysis. Multivariable logistic regression analysis was employed to identify independent predictors which were used to construct the clinical model, DLCT model, and combined model. A nomogram was formulated based on optimal performing model, and its performance was assessed using receiver operating characteristic curve, calibration curve, and decision curve analysis. The nomogram was subsequently tested in the validation set. Results: Independent predictors associated with malignant TNs with indeterminate cytology included NICP in the arterial phase, Hashimoto's Thyroiditis (HT), and BRAF V600E (all p < 0.05). The DLCT-clinical nomogram, incorporating the aforementioned variables, exhibited superior performance than the clinical model or DLCT model in both training set (AUC: 0.875 vs 0.792 vs 0.824) and validation set (AUC: 0.874 vs 0.792 vs 0.779). The DLCT-clinical nomogram demonstrated satisfactory calibration and clinical utility in both training set and validation set. Conclusion: The DLCT-clinical nomogram emerges as an effective tool to detect malignant lesions in cytologically indeterminate TNs.

Computed tomography for evaluation of abdominal wall hernias-what is the value of the Valsalva maneuver?

PURPOSE: To investigate the differences in the visibility and size of abdominal wall hernias in computed tomography (CT) with and without Valsalva maneuver. METHODS: This single-center retrospective study included consecutive patients who underwent abdominal CTs with Valsalva maneuver between January 2018 and January 2022. Inclusion criteria was availability of an additional non-Valsalva CT within 6 months. A combined reference standard including clinical and surgical findings was used. Two independent, blinded radiologists measured the hernia sac size and rated hernia visibility on CTs with and without Valsalva. Differences were tested with a Wilcoxon signed rank test and McNemar's test. RESULTS: The final population included 95 patients (16 women; mean age 46 ± 11.6 years) with 205 hernias. Median hernia sac size on Valsalva CT was 31 mm compared with 24 mm on non-Valsalva CT (p < 0.001). In 73 and 82% of cases, the hernias were better visible on CT with Valsalva as compared to that without. 14 and 17% of hernias were only visible on the Valsalva CT. Hernia visibility on non-Valsalva CT varied according to subtype, with only 0 and 3% of umbilical hernias not being visible compared with 43% of femoral hernias. CONCLUSIONS: Abdominal wall hernias are larger and better visible on Valsalva CT compared with non-Valsalva CT in a significant proportion of patients and some hernias are only visible on the Valsalva CT. Therefore, this method should be preferred for the evaluation of abdominal wall hernias.

Predominant determinants for evaluation of right parasternal approach in transthoracic echocardiography in aortic stenosis: a study based on three-dimensional cardiac computed tomography analysis.

The maximum blood flow velocity through the aortic valve (AVmax) using Doppler transthoracic echocardiography (TTE) is important in assessing the severity of aortic stenosis (AS). The right parasternal (RP) approach has been reported to be more useful than the apical approach, but the anatomical rationale has not been studied. We aimed to clarify the influence of the angle formed by the ascending aorta and left ventricle on Doppler analysis by TTE (Sep-Ao angle) and three-dimensional multidetector computed tomography (3D-MDCT) in patients with AS. A total of 151 patients evaluated using the RP approach and 3D-MDCT were included in this study. The Sep-Ao angle determined using TTE was compared with that determined using 3D-MDCT analysis. In MDCT analysis, the left ventricular (LV) axis was measured in two ways and the calcification score was calculated simultaneously. The Sep-Ao angle on TTE was consistent with that measured using 3D-MDCT. In patients with an acute Sep-Ao angle, the Doppler angle in the apical approach was larger, potentially underestimating AVmax. Multivariate analysis revealed that an acute Sep-Ao angle, large Doppler angle in the apical approach, smaller Doppler angle in the RP approach, and low aortic valve calcification were independently associated with a higher AVmax in the RP approach than in the apical approach. The Sep-Ao angle measured using TTE reflected the 3D anatomical angle. In addition to measurements using the RP approach, technical adjustments to minimize the Doppler angle to avoid bulky calcification should always be noted for accurate assessment.

Utility of Ultrahigh-Resolution Computed Tomography for Laryngeal Reconstructive Surgery.

OBJECTIVE: Unilateral vocal fold paralysis (UVFP) presents as incomplete glottal closure and leads to breathy hoarseness. Various treatments, including laryngeal framework surgery (type 1 thyroplasty [TP1] and arytenoid adduction [AA]), have been devised to correct this condition. Ultrahigh-resolution computed tomography (U-HRCT) allows detailed three-dimensional imaging of the larynx, which aids our understanding of vocal fold motion disorders. This study assessed whether U-HRCT is beneficial for correct diagnosis and surgical planning. METHODS: The participants were 26 UVFP patients who underwent laryngeal framework surgery (TP1 and/or AA). U-HRCT was used to measure the vocal fold volume (VFV) and level difference (LD). The need to combine AA with TP1 to obtain satisfactory surgical outcomes was evaluated by U-HRCT and various voice function tests. RESULTS: VFV was smaller in paralyzed folds than in unaffected folds. LD correlated strongly with voice parameters and showed high intra-rater and inter-rater reliability. The surgical outcome of the laryngeal framework surgery performed was judged to be excellent for improving voice function. Comparison of LD between the TP1 group and TP1 + AA group indicated that LD is an excellent parameter to determine the need to combine AA with TP1. CONCLUSION: These findings underscore the value of preoperative U-HRCT, especially LD, in surgical decision-making and afford insights for optimal phonosurgery and individualized intervention. Patients with LD >1.0 mm may benefit from thyroplasty with AA. LEVEL OF EVIDENCE: Level 3 (case-control study) Laryngoscope, 2024.

Ultra-high resolution computed tomography with deep-learning-reconstruction: diagnostic ability in the assessment of gastric cancer and the depth of invasion.

PURPOSE: To evaluate the image quality of ultra-high-resolution CT (U-HRCT) images reconstructed using an improved deep-learning-reconstruction (DLR) method. Additionally, we assessed the utility of U-HRCT in visualizing gastric wall structure, detecting gastric cancer, and determining the depth of invasion. METHODS: Forty-six patients with resected gastric cancer who underwent preoperative contrast-enhanced U-HRCT were included. The image quality of U-HRCT reconstructed using three different methods (standard DLR [AiCE], improved DLR-AiCE-Body Sharp [improved AiCE-BS], and hybrid-IR [AIDR3D]) was compared. Visualization of the gastric wall's three-layered structure in four regions and the visibility of gastric cancers were compared between U-HRCT and conventional HRCT (C-HRCT). The diagnostic ability of U-HRCT with the improved AiCE-BS for determining the depth of invasion of gastric cancers was assessed using postoperative pathology specimens. RESULTS: The mean noise level of U-HRCT with the improved AiCE-BS was significantly lower than that of the other two methods (p < 0.001). The overall image quality scores of the improved AiCE-BS images were significantly higher (p < 0.001). U-HRCT demonstrated significantly better conspicuity scores for the three-layered structure of the gastric wall than C-HRCT in all regions (p < 0.001). In addition, U-HRCT was found to have superior visibility of gastric cancer in comparison to C-HRCT (p < 0.001). The correct diagnostic rates for determining the depth of invasion of gastric cancer using C-HRCT and U-HRCT were 80%. CONCLUSIONS: U-HRCT reconstructed with the improved AiCE-BS provides clearer visualization of the three-layered gastric wall structure than other reconstruction methods. It is also valuable for detecting gastric cancer and assessing the depth of invasion.

Swirl sign score system: a novel and practical tool for predicting hematoma expansion risk after spontaneous intracerebral haemorrhage.

OBJECTIVE: To methodically analyse the swirl sign and construct a scoring system to predict the risk of hematoma expansion (HE) after spontaneous intracerebral haemorrhage (sICH). METHODS: We analysed 231 of 683 sICH patients with swirl signs on baseline noncontrast CT (NCCT) images. The characteristics of the swirl sign were analysed, including the number, maximum diameter, shape, boundary, minimum CT value of the swirl sign, and the minimum distance from the swirl sign to the edge of the hematoma. In the development cohort, univariate and multivariate analyses were used to identify independent predictors of HE, and logistic regression analysis was used to construct the swirl sign score system. The swirl sign score system was verified in the validation cohort. RESULTS: The number and the minimum CT value of the swirl sign were independent predictors of HE. The swirl sign score system was constructed (2 points for the number of swirl signs >1 and 1 point for the minimum CT value ≤41 Hounsfield units). The area under the curve of the swirl sign score system in predicting HE was 0.773 and 0.770 in the development and validation groups, respectively. CONCLUSIONS: The swirl sign score system is an easy-to-use radiological grading scale that requires only baseline NCCT images to effectively identify subjects at high risk of HE. ADVANCES IN KNOWLEDGE: Our newly developed semiquantitative swirl sign score system greatly improves the ability of swirl sign to predict HE.

Modern imaging of acute pulmonary embolism.

The first-choice imaging test for visualization of thromboemboli in the pulmonary vasculature in patients with suspected acute pulmonary embolism (PE) is multidetector computed tomography pulmonary angiography (CTPA) - a readily available and widely used imaging technique. Through technological advancements over the past years, alternative imaging techniques for the diagnosis of PE have become available, whilst others are still under investigation. In particular, the evolution of artificial intelligence (AI) is expected to enable further innovation in diagnostic management of PE. In this narrative review, current CTPA techniques and the emerging technology photon-counting CT (PCCT), as well as other modern imaging techniques of acute PE are discussed, including CTPA with iodine maps based on subtraction or dual-energy acquisition, single-photon emission CT (SPECT), magnetic resonance angiography (MRA), and magnetic resonance direct thrombus imaging (MRDTI). Furthermore, potential applications of AI are discussed.