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Purpose: To determine whether switching to contrast media based on the sharing of N-(2,3-dihydroxypropyl) carbamoyl side chain reduces the recurrence of iodinated contrast media (ICM)-associated adverse drug reactions (ADRs). Materials and methods: This single-center retrospective study included 2133 consecutive patients (mean age ± SD, 56.1 ± 11.4 years; male, 1052 [49.3%]) who had a history of ICM-associated ADRs and underwent contrast-enhanced CT examinations. The per-patient and per-exam-based recurrence ADR rates were compared between cases of switching and non-switching the ICM from ICMs that caused the previous ADRs, and between cases that used ICMs with common and different carbamoyl side chains from ICMs that caused the previous ADRs. Downgrade rates (no recurrence or the occurrence of ADR less severe than index ADRs) were also compared. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analysis were additionally performed. Results: In per-patient analysis, switching of ICM showed a lower recurrence rate (switching, 10.4% [100/965] vs. non-switching, 28.4% [332/1168]), with the adjusted odds ratio (OR) of 0.27 (95% CI: 0.21, 0.34; p < 0.001). The result was consistent in PSM (OR, 0.29 [95% CI: 0.22, 0.39]; p < 0.001), IPTW (OR, 0.28 [95% CI: 0.22, 0.36]; p < 0.001), and in per-exam analysis (5.5% vs. 13.8%; OR, 0.32 [95% CI: 0.27, 0.37]; p < 0.001). There was lower per-exam recurrence (5.0% [195/3938] vs. 7.8% [79/1017]; OR, 0.63 [95% CI: 0.47, 0.83]; p = 0.001) and higher downgrade rates (95.6% [3764/3938] vs. 93.3% [949/1017]; OR, 1.51 [95% CI: 1.12, 2.03]; p = 0.006) when using different side chain groups. Conclusion: Switching to an ICM with a different carbamoyl side chain reduced the recurrent ADRs and their severity during subsequent examinations. Clinical relevance statement: Switching to an iodinated contrast media with a different carbamoyl side chain reduced the recurrent adverse drug reactions and their severity during subsequent examinations. Key Points: Patients who experience adverse drug reactions from iodinated contrast media (ICM) may need to undergo contrast-enhanced studies again. Switching of ICM away from the ICM that caused the previous adverse drug reactions showed significantly lower recurrence rates. Compared to common side chain groups, there were significant differences in the per-exam recurrence rates and downgrade rates when using ICMs with different side chains. [ABSTRACT FROM AUTHOR]

Objective To evaluate the efficacy of dual-energy CT (DECT) water -hydroxyapatite (HAP) decomposition technique for detecting acute vertebral fractures. Methods Fifty consecutive patients who underwent both DECT and MRI of the thoracolumbar spine after trauma were retrospectively enrolled. Conventional linear-blended CT scans and corresponding water-HAP reconstructions were obtained. Four radiologists with 1, 5, 8 and 12 years of experience independently evaluated the gray-scale CT for the presence of fractures and their suspected age. The water -HAP images were then blindly assessed by the same readers to detect bone marrow edema. Findings were compared with those from fat-suppressed T2-weighted MRI as the standard. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) analyses for diagnostic performance and matched pair analyses were performed. Results Fifty-four fractures were classified as acute and 38 as chronic on MRI. The diagnostic performance of all readers in the detection of acute fractures improved from 0.76, 0.75, 0.82, and 0.84 with conventional CT alone to 0.87, 0.89, 0.92, and 0.93 in combination with water-HAP images, respectively. The diagnostic sensitivity increased from 0.83, 0.89, 0.66, and 0.71 to 0.93, 0.98, 0.79, and 0.84 whereas the specificity increased from 0.83, 0.87, 0.63, and 0.79 to 0.94, 0.94, 0.82, and 0.92, respectively. The PPV increased from 0.78, 0.81, 0.74, and 0.82 to 0.86, 0.90, 0.88, and 0.97 whereas the NPV increased from 0.76, 0.85, 0.73, and 0.81 to 0.88, 0.94, 0.91, and 0.92, respectively. The number of vertebrae rated as uncertain vertebral fracture decreased from 23, 21, 19, and 12 to 7, 5, 5, and 1, respectively. The accuracy improved significantly with the water-HAP decomposition technique (P<0.05) and the number of patients potentially referred to MRI decreased from 14, 13, 14, and 11 to 4, 3, 3, and 1, respectively. Conclusion DECT based water -HAP decomposition technique can improve the diagnostic confidence of radiologists in acute vertebral compression fractures. [ABSTRACT FROM AUTHOR]

Objective To explore the application value of double-flow method of CT angiography using a mixture of normal saline and contrast agent before injection of contrast agent to achieve differential imaging within the human body in CT pulmonary angiography (CTPA). Methods Forty patients with clinically suspected pulmonary embolism at our hospital from January 2022 to March 2024 were randomly divided into monitoring scanning control group (20) and dual-flow scanning study group (20) for CTPA using Philips 128-row spiral CT. In the control group, region of interest (ROI) was placed in the superior vena cava (SVC) with a threshold of 150 HU, 50 mL iobitridol (350 mg I/mL) and 30 mL normal saline were continuously injected. In the experimental group, ROI was placed in the pulmonary trunk (PT) with a threshold of 60 HU, 6 mL of contrast agent and 16 mL of normal saline mixture, 17 mL of contrast agent and 3 mL of normal saline mixture, and 30 mL of normal saline solution were continuously injected. The CT values of PT, pulmonary vein (PV) and SVC of the two groups were measured and the image quality was compared. Results There was no significant difference (t=-2.16, -1.168; P>0.05) between the CT values of PT (371.35±60.16) and PV (153.8±30.29) in the control group and that of the experimental group (360.1±48.09, 154.25±45.97). These numbers are the same for both groups. The SVC CT value of the study group (198.5±55.97) was significantly lower (t=-8.048, P<0.05) than that of the control group (1001.25±299.55). There was no significant difference in pulmonary artery subjective scores between the experimental group and the control group (P=0.085). The subjective score of superior vena cava artifact in the experimental group was significantly higher than that in the control group (P=0.000). Conclusion Double-flow CTPA uses less contrast agent with decreased enhancement of SVC and better PT image quality. [ABSTRACT FROM AUTHOR]

Purpose: In this cross-sectional study, we aimed to characterize how frequently the anatomy of interest (AOI) was excluded when evaluating genital pathology using the current CT pelvis protocol recommended by the American College of Radiology and evaluate how AOI exclusion affects patient management. Methods: We retrospectively reviewed medical records, using diagnosis and CPT codes, of patients admitted with genital pathology who obtained a CT scan at our institution from July 1, 2020–April 30, 2023. Baseline patient demographics were included. Data about each index CT scan (scan obtained at our institution) were recorded and assessed for exclusion of the AOI. Statistical analysis was performed to determine the rate of AOI exclusion and to compare patient management between patients with AOI excluded versus those without AOI exclusion. Results: 113 presentations for genital pathology included an index CT scan and were included for analysis. Patients were primarily men (98%) with a mean age of 53.1 years (SD 13.9). The most common diagnoses were Fournier's gangrene (35%), scrotal abscess (22%) and unspecified infection (19%). 26/113 scans (23%) did not capture the entire AOI. When the AOI was missed during the index scan, there was a higher rate of obtaining additional scans (38% vs. 21%), but a similar rate of intervention (77% vs. 63%) when compared to index scans that captured the entire AOI. 35 scans (31%) had protocol-extending instructions; index scans that captured the entire AOI were more likely to have specific protocol-extending instructions (38% vs. 8% p < 0.01). Conclusions: Creating a specific CT protocol for genital pathology could decrease the amount of inappropriate irradiation and improve AOI capture rates without relying on specific request for protocol deviation. [ABSTRACT FROM AUTHOR]

Objective To explore the value of computerized tomography (CT) and magnetic resonance imaging (MRI) imaging features in differential diagnosis of giant cell tumors with prominent aneurysmal bone cysts (GABCs) in the extremities and primary aneurysmal bone cysts (PABCs). Methods In this study, the CT and MRI imaging features of 20 patients with GABCs in the extremities and 21 patients with PABCs were retrospectively analyzed, and the age and sex of patients were collected. The differences in different indicators between the two groups were compared. The diagnostic sensitivity and specificity for GABCs and PABCs were calculated based on the age, transverse/longitudinal diameter ratio of the mass, subchondral bone involvement, deep edge lobulation of the lesion, and vascular shadow around the mass. Results There were significant differences in the age and transverse/longitudinal diameter ratio of the mass between the two groups (t=-3.956,-2.985,P

Background: High-quality images with minimum radiation dose are considered a challenge in Computed Tomography (CT) scans.Objective: The current study aimed to assess the efficacy of the Iterative Reconstruction in Image Space (IRIS) algorithm combined with Automatic Tube Current Modulation (ATCM) compared to Filtered Back Projection (FBP) in brain CT scans.Material and Methods: In this cross-sectional study, 200 patients underwent to brain CT scan, and images were then reconstructed using both FBP and IRIS. The CT Number (CTN), noise, and Signal-to-Noise Ratio (SNR) were computed for different tissues from CT images. The performance of two algorithms under different exposure conditions was evaluated using a water phantom. Two experienced radiologists assessed the image quality. Volume CT Dose Index (CTDIvol) and Dose Length Product (DLP) were recorded for each scan.Results: FBP reconstruction exhibited higher noise and lower SNR compared to IRIS, both with and without ATCM. Noise levels significantly increased for FBP combined with ATCM. Subjective analysis showed higher performance for IRIS without ATCM compared to other approaches. The mean CTDIvol with and without ATCM was 20.04±3.33 and 36.37±4.65 mGy, respectively. In the phantom study, the noise with IRIS remained lower than that with FBP even with a 42% dose reduction. Conclusion: IRIS algorithm can preserve the image quality when radiation dose is significantly reduced by ATCM in brain CT scan. Implementation of IRIS combined with ATCM is recommended for brain CT examinations.

Abstract Background The application of radiomics in thoracic lymph node metastasis (LNM) of lung adenocarcinoma is increasing, but diagnostic performance of radiomics from primary tumor to predict LNM has not been systematically reviewed. Therefore, this study sought to provide a general overview regarding the methodological quality and diagnostic performance of using radiomic approaches to predict the likelihood of LNM in lung adenocarcinoma. Methods Studies were gathered from literature databases such as PubMed, Embase, the Web of Science Core Collection, and the Cochrane library. The Radiomic Quality Score (RQS) and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) were both used to assess the quality of each study. The pooled sensitivity, specificity, and area under the curve (AUC) of the best radiomics models in the training and validation cohorts were calculated. Subgroup and meta-regression analyses were also conducted. Results Seventeen studies with 159 to 1202 patients each were enrolled between the years of 2018 to 2022, of which ten studies had sufficient data for the quantitative evaluation. The percentage of RQS was between 11.1% and 44.4% and most of the studies were considered to have a low risk of bias and few applicability concerns in QUADAS-2. Pyradiomics and logistic regression analysis were the most commonly used software and methods for radiomics feature extraction and selection, respectively. In addition, the best prediction models in seventeen studies were mainly based on radiomics features combined with non-radiomics features (semantic features and/or clinical features). The pooled sensitivity, specificity, and AUC of the training cohorts were 0.84 (95% confidence interval (CI) [0.73–0.91]), 0.88 (95% CI [0.81–0.93]), and 0.93(95% CI [0.90–0.95]), respectively. For the validation cohorts, the pooled sensitivity, specificity, and AUC were 0.89 (95% CI [0.82–0.94]), 0.86 (95% CI [0.74–0.93]) and 0.94 (95% CI [0.91–0.96]), respectively. Conclusions Radiomic features based on the primary tumor have the potential to predict preoperative LNM of lung adenocarcinoma. However, radiomics workflow needs to be standardized to better promote the applicability of radiomics. Trial registration CRD42022375712.

Background/Aims: Despite advances in imaging and endoscopic technology, diagnostic modalities for small bowel tumors are simultaneously performed. We investigated the discrepancy rate between each modality and predictive factors of discrepancy in patients with definite small bowel tumors. Methods: Data of patients with definite small bowel tumors who underwent both device-assisted enteroscopy (DAE) and computed tomography (CT) were retrieved from web-based enteroscopy registry database in Korea. Predictive risk factors associated with discrepancy were analyzed using logistic regression analysis. Results: Among 998 patients, 210 (21.0%) were diagnosed with small bowel tumor using DAE, in 193 patients with definite small bowel tumor, DAE and CT were performed. Of these patients, 12 (6.2%) showed discrepancy between examinations. Among 49 patients who underwent DAE and video capsule endoscopy (VCE) examination, 13 (26.5%) showed discrepancy between examinations. No significant independent risk factors were associated with concordance between DAE and CT in multivariate logistic regression analysis among the patients. In a multivariate logistic regression analysis, red blood cell transfusion was negatively associated with concordance between DAE and VCE in patients with small bowel tumor (odds ratio, 0.163; 95% confidence interval, 0.026 to 1.004; p=0.050). Conclusions: For small bowel tumors, the discrepancy rate between DAE and CT was 6.2%, and 26.5% between DAE and VCE. Despite developments in cross-sectional imaging (VCE and DAE modalities), discrepancies still exist. For small bowel bleeding that require significant transfusion while showing insignificant VCE findings, DAE should be considered as the next diagnostic approach, considering the possibility of missed small bowel tumor. [ABSTRACT FROM AUTHOR]

Purpose: This study examines the hepatic extracellular volume fraction (ECV) disparity between the left and right lobes (ECV_left and ECV_right) in patients with chronic thromboembolic pulmonary hypertension (CTEPH), its association with right heart catheterization (RHC) metrics, and with intolerance to increased pulmonary hypertension (PH)-targeted medication dosages. Methods: We retrospectively analyzed 72 CTEPH-diagnosed patients who underwent equilibrium-phase abdominal dual-energy CT (DECT) and RHC. Hepatic ECVs, derived from DECT's iodine maps using circular regions of interest in the liver and aorta, were correlated with RHC parameters via Spearman's rank correlation and lobe differences through the Wilcoxon signed-rank test. Logistic regression assessed cases with ECV_left exceeding ECV_right by > 0.05, while receiver operating characteristic curve analysis gauged ECVs' predictive power for medication intolerance. Results: Of the 72 patients (57 females; median age 69), ECV_total (0.24, IQR 0.20–0.27) moderately correlated with RHC parameters (rs = 0.28, −0.24, 0.3 for mean pulmonary arterial pressure, cardiac index [CI], and pulmonary vascular resistance index, respectively). ECV_left significantly surpassed ECV_right (0.25 vs. 0.22, p < 0.001), with a greater ECV_left by > 0.05 indicating notably lower CI (p < 0.001). In 27 patients on PH medication, ECV_left effectively predicted medication intolerance (AUC = 0.84). Conclusion: In CTEPH patients, hepatic ECV correlated with RHC metrics, where elevated left lobe ECV suggested reduced CI and potential medication intolerance. The hepatic extracellular volume fraction (ECV), measured via dual-energy CT, was notably higher in the left lobe compared to the right in patients with chronic thromboembolic pulmonary hypertension, with elevated ECV in the left lobe correlating with reduced cardiac index and intolerance to medication. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Our objective was to investigate the utility of fluorodeoxyglucose positron emission tomography‐computed tomography (FDG PET‐CT) in assessing CT Stage 1A non‐small cell lung cancer (NSCLC) in patients under consideration for curative treatment. Performing FDG PET‐CT in these patients may lead to unnecessary delays in treatment if it can be shown to provide no added value.We retrospectively reviewed 735 lesions in 653 patients from the New Zealand Te Whatu Ora Northern region lung cancer database with suspected or pathologically proven Stage 1A NSCLC on CT scan who also underwent FDG PET‐CT imaging. We determined how often FDG PET‐CT findings upstaged patients and then compared to pathological staging where available.FDG PET‐CT provided an overall upstaging rate of 9.7%. Category‐specific rates were 0% in Tis, 0.9% in T1mi, 7.4% in T1a, 10% in T1b and 12% in T1c groups. The percentage of lesions upstaged on FDG PET‐CT that remained Stage 1A was 100% in T1mi, 100% in T1a, 47.1% in T1b and 40.7% in T1c groups. The P value was statistically significant at 0.004, indicating upstaging beyond Stage 1A was dependent on T category.Our data suggests that FDG PET‐CT is indicated for T1b and T1c lesions but is of limited utility in Tis, T1mi and T1a lesions. Adopting a more targeted approach and omitting FDG PET‐CT in patients with Tis, T1mi, and T1a lesions may benefit all patients with lung cancer by improving accessibility and treatment timelines. [ABSTRACT FROM AUTHOR]

Objective To analyze the clinical and imaging features of Dyke-Davidoff-Masson syndrome (DDMS). Methods The clinical data, unenhanced CT (12) and MRI (4) of 13 patients with type I (6), II (4), and III (3), acquired (8) and congenital (5) DDMS were retrospectively analyzed. Three of the 13 patients underwent both CT and MRI. Results The clinical manifestations included epilepsy (12), hemiplegia (9), mental retardation (9), mental disorders (9), extremity atrophy (3), facial asymmetry (2), sexual dysfunction (1), and bilateral auricular malformation (1). The patients showed unilateral cerebral hemiatrophy and ipsilateral ventricle dilatation (13), ipsilateral midline structural shift (12), ipsilateral basal ganglia and cerebral peduncle atrophy (10), encephalomalacia (9), hippocampal atrophy (6), porencephaly (4), crossed cerebellar atrophy (3), bilateral cerebellar atrophy (3), corpus callosum hypoplasia (3), schizencephaly and agenesis of septum pellucidum (1). All 13 patients had varying degrees of ipsilateral compensatory cranial changes of calvarial thickening, excessive aeration of the frontal sinus and mastoid air cells. Conclusion The main clinical features of DDMS are epilepsy, hemiplegia, mental retardation and mental disorders. Unilateral cerebral hemisphere atrophy and ipsilateral compensatory cranial changes are typical imaging features. [ABSTRACT FROM AUTHOR]

Objective To evaluate the image quality of CT portal venography (CTPV) under low radiation dose conditions at 100 kVp using a second-generation dual-layer detector spectral CT (DLCT). Methods A total of 110 patients [54 men, 56 women, mean age: (57.47±15.07) years] underwent abdominal contrast-enhanced DLCT from May 2023 to March 2024. The patients were randomly divided into a control group (120 kVp, n=50) and a study group (100 kVp, n=60). The original CTPV data from the control group were reconstructed into conventional mixed-energy images (CI), while the data from the study group were reconstructed into CI and virtual monoenergetic images (VMI) at 40-80 keV intervals (10 keV steps). The CT values, standard deviation (SD), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of the main portal vein and its left and right branches were measured. Subjective image quality was assessed by two radiologists. Results The effective radiation dose (ED) for the study group [(1.92±0.21) mSv] was 52.59% lower than that of control group [(4.05±1.23) mSv]. The average CT values, SNR, and CNR of the portal vein and its branches in the 40, 50, and 60 keV VMIs of the study group were significantly higher than those in the CIs of both groups (all P<0.0001), with the highest SNR and CNR observed at 40 and 50 keV VMIs. There was no significant difference in the SNR and CNR between 40 and 50 keV VMIs (P<0.05). The SD of 40 and 50 keV VMIs in the study group was comparable to that of control (P>0.05) whereas the SD of 60-80 keV VMIs was significantly lower than that of control (P<0.05). Subjective image quality assessment showed that 50 keV VMI had the highest proportion of scores rated as 5 (best) at 75% with good interobserver agreement (all K>0.8). Conclusion Using 50 keV VMI with 100 kVp DLCT provides image quality that meets clinical diagnostic requirements while significantly reducing radiation dose compared to conventional images at 120 kVp. [ABSTRACT FROM AUTHOR]

Objective To study the feasibility of spectral CT virtual monoenergetic imaging (VMI) for one-stop coronary artery and vein examination. Methods From December 2023 to January 2024, an experimental group of 25 patients underwent coronary artery and vein CT imaging using personalized scanning protocols and a randomly selected controlled group of 25 patients underwent coronary artery CT imaging using routine scanning protocols. The conventional images of the experimental group as group B1, and the 40 keV virtual monoenergetic reconstructed images as group B2. The CT image quality of the control group (A), conventional CT (B1) and 40 keV VMI (B2) of the experimental group was evaluated quantitively including CT values, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of coronary artery branches. Subjective evaluations were completed by two experienced radiologists using a 5-point scale, and the inter-rater reliability was analyzed using the Kappa test. Group comparisons were conducted using the Mann-Whitney test. Results CT values, SNR and CNR of the left main coronary arteries [(1306.07±185.16) HU, 101.820± 38.10, 113.91±42.13], right coronary arteries [(1284.97±203.8) HU, 99.99±37.61, 112.10±41.53], left circumflex coronary arteries [(1191.88±182.83) HU, 93.01±36.10, 105.11±39.92], and left anterior descending arteries [(1202.44±185.50) HU, 88.05±33.57, 106.33±41.84] in group B2 were significantly higher (P<0.001) than that of groups A and B1. The CT values, SNR and CNR values of the coronary veins including coronary sinus, great cardiac vein, posterior intraventricular vein, anterior interventricular vein, posterior vein of the left ventricle, and left marginal vein in group B2 were also significantly higher (P<0.001) than that of group B1. The subjective image quality scores of B2 group (5, 5) were better than that of groups A and B1 with good consistency (κ>0.7). Conclusion Spectral CT VMI allows one-stop examination of the coronary arteries and veins. [ABSTRACT FROM AUTHOR]

Objective To investigate the value of dual-layer detector spectral CT in the differential diagnosis of arterial phase hyperenhancement (APHE) liver metastases and hepatocellular carcinoma (HCC). Methods Fifty-three patients with clinical or pathologically confirmed APHE liver metastasis (23) and HCC (30) from December 2021 to June 2023 were included in this retrospective study . The spectral CT parameters on the standardized virtual monoenergetic image (VMI) including tumor / liver standardized iodine no water (NINW-Ltumor to liver), tumor/liver standardized iodine density (NID-L), tumor/liver standardized Z-effective (NZeff-L), and tumor/abdominal aorta NZeff (NZeff-Atumor to aorta) were calculated. The receiver operating characteristic (ROC) curve and Cohen d were used to analyze the diagnostic effectiveness of these parameters. Results In the arterial phase, the CT values of liver on 40 keV (NCT-L40keV), 50 keV (NCT-L50keV), and 60 keV (NCT-L60keV) VMI, NINW-L, NID-L, NZeff-L and NZeff-A of APHE liver metastases were significantly less than that of HCC (P<0.05). The area under the ROC curve of NINW-L in the arterial phase was the highest at 0.752. The 0.298 threshold value of NINW -L in the arterial phase had the best differentiation between liver metastases and HCC with 63.3% sensitivity and 87.0% specificity. Conclusion NCT-L40keV, NINW-L and NID-L in the arterial phase are valuable for differentiating APHE liver metastasis from HCC. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate diagnostic performance and image quality of ultralow-dose CT (ULDCT) in diagnosing acute appendicitis with an image-based deep-learning denoising algorithm (IDLDA). Methods: This retrospective multicenter study included 180 patients (mean ± standard deviation, 29 ± 9 years; 91 female) who underwent contrast-enhanced 2-mSv CT for suspected appendicitis from February 2014 to August 2016. We simulated ULDCT from 2-mSv CT, reducing the dose by at least 50%. Then we applied an IDLDA on ULDCT to produce denoised ULDCT (D-ULDCT). Six radiologists with different experience levels (three board-certified radiologists and three residents) independently reviewed the ULDCT and D-ULDCT. They rated the likelihood of appendicitis and subjective image qualities (subjective image noise, diagnostic acceptability, and artificial sensation). One radiologist measured image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). We used the receiver operating characteristic (ROC) analyses, Wilcoxon's signed-rank tests, and paired t-tests. Results: The area under the ROC curves (AUC) for diagnosing appendicitis ranged 0.90–0.97 for ULDCT and 0.94–0.97 for D-ULDCT. The AUCs of two residents were significantly higher on D-ULDCT (AUC difference = 0.06 [95% confidence interval, 0.01–0.11; p =.022] and 0.05 [0.00–0.10; p =.046], respectively). D-ULDCT provided better subjective image noise and diagnostic acceptability to all six readers. However, the response of board-certified radiologists and residents differed in artificial sensation (all p ≤.003). D-ULDCT showed significantly lower image noise, higher SNR, and higher CNR (all p <.001). Conclusion: An IDLDA can provide better ULDCT image quality and enhance diagnostic performance for less-experienced radiologists. [ABSTRACT FROM AUTHOR]

Purpose: Gold–silica nanoshell therapy [AuroShells with subsequent focal laser therapy (AuroLase)] is an emerging targeted treatment modality for prostate cancer. We reviewed pre- and post-treatment unenhanced CT imaging to assess for retained gold–silica nanoshells in the abdomen and pelvis. Methods: This single-institution retrospective study identified patients in the AuroLase pilot who underwent pre- and post-treatment unenhanced abdominopelvic CT. The attenuation, before and after gold–silica nanoshell administration, of the liver, spleen, pancreas, kidneys, prostate, blood pool, paraspinal musculature, and abnormal lymph nodes were manually measured by two readers. After inter-reader agreement was calculated using intraclass correlation (ICC), a permutation test was used to assess pre- and post-therapy attenuation differences. Results: Four patients met the inclusion criteria. Mean age was 72.3 ± 5.9 years. Median time interval between pre-treatment CT and treatment, and between treatment and post-treatment CT, was 232 days and 236.5 days, respectively. The two readers' attenuation measurements had very high agreement (ICC = 0.99, p < 0.001). The highest differences in organ attenuation between pre- and post-therapy scans were seen in all four patients in the liver and spleen (liver increased by an average of 28.9 HU, p = 0.010; spleen increased by an average of 63.7 HU, p = 0.012). A single measured lymph node increased by an average of 58.9 HU. In the remainder of the measured sites, the change in attenuation from pre- to post-therapy scans ranged from -0.1 to 3.8 HU (p > 0.05). Conclusion: Increased attenuation of liver and spleen at CT can be an expected finding in patients who have received gold–silica nanoshell therapy. [ABSTRACT FROM AUTHOR]

Background: The application of radiomics in thoracic lymph node metastasis (LNM) of lung adenocarcinoma is increasing, but diagnostic performance of radiomics from primary tumor to predict LNM has not been systematically reviewed. Therefore, this study sought to provide a general overview regarding the methodological quality and diagnostic performance of using radiomic approaches to predict the likelihood of LNM in lung adenocarcinoma. Methods: Studies were gathered from literature databases such as PubMed, Embase, the Web of Science Core Collection, and the Cochrane library. The Radiomic Quality Score (RQS) and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) were both used to assess the quality of each study. The pooled sensitivity, specificity, and area under the curve (AUC) of the best radiomics models in the training and validation cohorts were calculated. Subgroup and meta-regression analyses were also conducted. Results: Seventeen studies with 159 to 1202 patients each were enrolled between the years of 2018 to 2022, of which ten studies had sufficient data for the quantitative evaluation. The percentage of RQS was between 11.1% and 44.4% and most of the studies were considered to have a low risk of bias and few applicability concerns in QUADAS-2. Pyradiomics and logistic regression analysis were the most commonly used software and methods for radiomics feature extraction and selection, respectively. In addition, the best prediction models in seventeen studies were mainly based on radiomics features combined with non-radiomics features (semantic features and/or clinical features). The pooled sensitivity, specificity, and AUC of the training cohorts were 0.84 (95% confidence interval (CI) [0.73–0.91]), 0.88 (95% CI [0.81–0.93]), and 0.93(95% CI [0.90–0.95]), respectively. For the validation cohorts, the pooled sensitivity, specificity, and AUC were 0.89 (95% CI [0.82–0.94]), 0.86 (95% CI [0.74–0.93]) and 0.94 (95% CI [0.91–0.96]), respectively. Conclusions: Radiomic features based on the primary tumor have the potential to predict preoperative LNM of lung adenocarcinoma. However, radiomics workflow needs to be standardized to better promote the applicability of radiomics. Trial registration: CRD42022375712. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the distribution of coronal plane alignment of the knee (CPAK) classification and functional knee phenotypes in a Chinese osteoarthritis (OA) population and to compare different lower limb alignment targets according to the distribution characteristics to find suitable total knee arthroplasty (TKA) bone cut strategies for the Chinese OA patients. Methods: The computed tomography (CT) images were retrospectively collected and the three‐dimensional (3D) models were reconstructed from 434 Chinese OA patients, including 93 males and 341 females, with a mean age of 66.4 ± 9.3 years. Femoral mechanical angle (FMA), tibial mechanical angle (TMA) and mechanical hip–knee–ankle angle (mHKA) were measured on the 3D models. Arithmetic hip–knee–ankle angle (aHKA) was calculated using FMA plus TMA, and joint line obliquity was calculated as 180 + TMA–FMA. The CPAK according to MacDessi and the functional knee phenotypes according to Hirschmann were performed. In addition, the suitable TKA bone cut strategies were explored according to the phenotypes and based on the characteristics of different alignment targets, such as mechanical alignment, anatomic alignment (AA), kinematic alignment, restricted KA (rKA) and adjusted MA (aMA). Statistical differences were determined using the independent‐samples t‐test or the two independent‐samples Wilcoxon test, with p < 0.05 considered statistically significant. Results: The Chinese OA population showed a varus alignment tendency (mHKA = 172.1° ± 7.2°), to which the TMA was a major contributor (TMA = 84.7° ± 4.4° vs. FMA = 91.3° ± 3.2°). The mHKA was on average 3.9° more varus than the aHKA. A total of 140 functional knee phenotypes were found and 45.6% were concentrated in VARFMA3°–NEUFMA0° to VARTMA3°–NEUTMA0°. More than 70% of patients had different FMA and TMA phenotypes. There were 92.9% of CPAK distributed in types I to IV, with type I accounting for 53.9%. The FMA phenotypes were less changed if the aMA and rKA were chosen, and the TMA phenotypes were less changed if the AA and rKA were chosen. Conclusion: Compared with the CPAK, the functional knee phenotypes were more suitable for the Chinese OA population with a wide distribution and a varus tendency, and it seemed more appropriate to choose aMA and rKA as TKA alignment targets for resection. Level of Evidence: Level Ⅲ. [ABSTRACT FROM AUTHOR]

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Abstract The goal of this experimental study was to quantify the influence of helical pitch and gantry rotation time on image quality and file size in ultrahigh-resolution photon-counting CT (UHR-PCCT). Cervical and lumbar spine, pelvis, and upper legs of two fresh-frozen cadaveric specimens were subjected to nine dose-matched UHR-PCCT scan protocols employing a collimation of 120 × 0.2 mm with varying pitch (0.3/1.0/1.2) and rotation time (0.25/0.5/1.0 s). Image quality was analyzed independently by five radiologists and further substantiated by placing normed regions of interest to record mean signal attenuation and noise. Effective mAs, CT dose index (CTDIvol), size-specific dose estimate (SSDE), scan duration, and raw data file size were compared. Regardless of anatomical region, no significant difference was ascertained for CTDIvol (p ≥ 0.204) and SSDE (p ≥ 0.240) among protocols. While exam duration differed substantially (all p ≤ 0.016), the lowest scan time was recorded for high-pitch protocols (4.3 ± 1.0 s) and the highest for low-pitch protocols (43.6 ± 15.4 s). The combination of high helical pitch and short gantry rotation times produced the lowest perceived image quality (intraclass correlation coefficient 0.866; 95% confidence interval 0.807–0.910; p

Objective To explore the value of computed tomography (CT) imaging features and texture analysis in the differential diagnosis of acinar cell carcinoma of the pancreas (ACCP). Methods The clinical data of patients who were patholo-gically diagnosed with ACCP, pancreatic ductal adenocarcinoma (PDAC), or solid pseudopapillary neoplasm (SPN) of the pancreas in our hospital from January 2017 to October 2018 were retrospectively analyzed. The clinical manifestations, tumor markers, CT imaging features, and texture parameters were compared and analyzed. Results The contrast-enhanced CT images of 5 patients with ACCP showed that most of the lesions were solid-cystic masses with a large size and more solid components. The CT images of 12 patients with PDAC showed that most of the lesions were solid masses with a small size. The CT images of 12 patients with SPN showed that most of the lesions were solid-cystic masses with a size greater than that of ACCP lesions and fewer solid components, showing the “floating cloud sign”. Eight texture parameters were valuable for the differential diagnosis between ACCP and PDAC (Z=2.015-2.530,P

Objective To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of immunoglobulin G4 (IgG4)-related autoimmune pancreatitis (AIP), to improve the understanding of the imaging features of this disease, and to reduce imaging misdiagnosis. Methods A retrospective analysis was performed on the clinical data of 47 patients with IgG4-related AIP, among whom 33 underwent plain CT scan and contrast-enhanced CT scan, 24 underwent plain MRI scan, contrast-enhanced MRI scan, and magnetic resonance cholangiopancreatography (MRCP) examination, and 10 underwent combined CT and MRI examination to observe the morphology, changes in density/signal, contrast enhancement characteristics of the diseased pancreas, the peripancreatic and pancreatic duct changes, and the manifestations out of the pancreas. Results The CT and MRI scans showed that among the 47 patients, 27 had a “sausage-like”, diffusely enlarged pancreas and 20 had a focally enlarged pancreas. The plain CT scan showed a uniform and slightly low density; the contrast-enhanced CT scan of the lesion showed an inhomogeneous patchy enhancement in arterial phase, and a uniformly delayed progressive enhancement in portal vein phase and delayed phase. The MRI scan of the lesion showed inhomogeneous and slight hypointensity on T1WI-FS and slight hyperintensity on T2WI, the contrast-enhanced MRI scan showed an inhomogeneous mild enhancement in the early stage and a uniformly delayed progressive enhancement on delayed scan. The CT and MRI scans showed that 28 patients had capsule-like edges around the panc-reas, namely “capsule sign”, with a mild to moderate delayed enhancement on contrast-enhanced images. The MRCP showed that 10 patients had segmental stenosis of the main pancreatic duct and localized mild dilatation of the upstream pancreatic duct. The CT and MRI scans showed that 30 patients had changes in the bile duct system, with wall thickening, stenosis, and delayed enrichment of the pancreatic segment of common bile duct. The MRCP showed “beak-like” changes, and dilatation of upstream intrahepatic and extrahepatic bile ducts to varying degrees. Conclusion The CT and MRI findings of IgG4-related AIP have certain characteristics. The combination of imaging findings and relevant laboratory tests can help improve the diagnosis of this disease.

Objective To investigate the value of preoperative CT evaluation of extramural vascular invasion in evaluating the prognosis of gastric cancer patients. Methods The patients who underwent gastrectomy in our hospital from January 2016 to December 2018 were enrolled as subjects, and preoperative CT examination was performed to evaluate extramural vascular invasion. The patients were followed up after surgery to observe overall survival (OS) and disease-free survival (DFS); the K-M curve and the log-rank test were used to analyze the association of extramural vascular invasion with OS and DFS, and the COX regression model was used to investigate the influencing factors for OS and DFS. Results The patients with a tumor diameter of ≥5 cm and TNM stage Ⅲ gastric cancer had a significantly higher incidence rate of extramural vascular invasion on preoperative CT evaluation than those with a tumor diameter of

Purpose: Traditional CT acquisition planning is based on scout projection images from planar anterior-posterior and lateral projections where the radiographer estimates organ locations. Alternatively, a new scout method utilizing ultra-low dose helical CT (3D Landmark Scan) offers cross-sectional imaging to identify anatomic structures in conjunction with artificial intelligence based Anatomic Landmark Detection (ALD) for automatic CT acquisition planning. The purpose of this study is to quantify changes in scan length and radiation dose of CT examinations planned using 3D Landmark Scan and ALD and performed on next generation wide volume CT versus examinations planned using traditional scout methods. We additionally aim to quantify changes in radiation dose reduction of scans planned with 3D Landmark Scan and performed on next generation wide volume CT. Methods: Single-center retrospective analysis of consecutive patients with prior CT scan of the same organ who underwent clinical CT using 3D Landmark Scan and automatic scan planning. Acquisition length and dose-length-product (DLP) were collected. Data was analyzed by paired t-tests. Results: 104 total CT examinations (48.1 % chest, 15.4 % abdomen, 36.5 % chest/abdomen/pelvis) on 61 individual consecutive patients at a single center were retrospectively analyzed. 79.8 % of scans using 3D Landmark Scan had reduction in acquisition length compared to the respective prior acquisition. Median acquisition length using 3D Landmark Scan was 26.7 mm shorter than that using traditional scout methods (p < 0.001) with a 23.3 % median total radiation dose reduction (245.6 (IQR 150.0–400.8) mGy cm vs 320.3 (IQR 184.1–547.9) mGy cm). CT dose index similarly was overall decreased for scans planned with 3D Landmark and ALD and performed on next generation CT versus traditional methods (4.85 (IQR 3.8–7) mGy vs. 6.70 (IQR 4.43–9.18) mGy, respectively, p < 0.001). Conclusion: Scout imaging using reduced dose 3D Landmark Scan images and Anatomic Landmark Detection reduces acquisition range in chest, abdomen, and chest/abdomen/pelvis CT scans. This technology, in combination with next generation wide volume CT reduces total radiation dose.

Objective To explore the value of quantitative dual-energy CT(DECT)parameters for predicting lateral cervical lymph node metastasis(LLNM)in patients with papillary thyroid carcinoma(PTC). Methods DECT of 216 patients with pathologically confirmed PTC including 174 with LLNM and 42 without LLNM was retrospectively analyzed. Quantitative DECT parameters including iodine concentration(IC), effective atomic number(Zeff), slope of spectral Hounsfield unit curve(λHU), normalized IC(NIC)and normalized Zeff(NZeff)in the non-contrast, arterial and venous phases were compared. Binary logistic regression was applied to analyze the independent predictors. Receiver operating characteristic(ROC)curve analysis was used to evaluate the performance of independent predictors and their combinations for predicting the LLNM. Results Compared with the non-LLNM group, LLNM group showed significantly lower NIC(Z=-2. 279, P=0. 023)in the non-contrast phase, higher IC, NIC, NZeff and λHU in the arterial phase(all P＜0. 05), and higher IC, NIC, Zeff and λHU in the venous phase(all P＜0. 05). Binary logistic regression analysis showed that NICs in the non-contrast and venous phases were independent predictors of LLNM. The predictive performance of the combined non-contrast and venous phase model is optimal with an area under ROC curves(AUC)of 0. 672(95％CI:0. 605-0. 734), sensitivity of 63. 79％, specificity of 66. 67％, followed by NIC in the venous phase(AUC=0. 634)and NIC in the non-contrast phase(AUC=0. 613). Conclusion DECT derived quantitative parameters can assist in predicting LLNM in patients with PTC. [ABSTRACT FROM AUTHOR]

Objective To investigate the efficacy of geometric characteristics and hemodynamics for evaluating the risk of abdominal aortic aneurysm(AAA)rupture. Methods Twenty-five patients with intact AAAs(iAAA group)and 25 patients with ruptured AAAs(rAAA group)from June 2019 to August 2023 were matched 1∶1 with covariates of gender and age. Geometric characteristics,risk factors for rupture,and hemodynamics of the AAAs were analyzed. Results The maximal AAA diameter[(Dmax:(5. 92±1. 50)cm,t=6. 947,P＜0. 05],diameter of AAA neck[Dneck:(2. 38±0. 50)cm,t=2. 563,P＜0. 05],the ratio of Dmax to diameter of normal aorta(Dmax/DAO:2. 54±0. 67,t=6. 567,P＜0. 05),Dmax/Dneck(2. 53±0. 62,t=6. 567,P＜0. 05),and normalized length of AAA(Lnor:22. 73±11. 08,t=4. 982,P＜0. 05)in rAAA group were significantly greater than that of iAAA group[(3. 67±0. 68)cm,(2. 06±0. 03)cm,1. 56±0. 34,1. 81±0. 38,10. 78±4. 59]. Multivariate logistic analysis showed that Dmax(OR=1. 824,95％CI:1. 459-6. 251)and Dmax/DAO(OR=4. 039,95％CI:3. 261-9. 155)were significant risk predictors for AAA rupture. The multivariate model using integrated geometric features had higher accuracy(94％)than conventional Dmax(88％)for predicting the risk of AAA rupture. rAAA had type Ⅲand iAAA had type Ⅱ blood flow patterns. rAAA had greater area of low wall shear stress(73. 9 cm²)than iAAA(67. 8 cm²). Conclusion Evaluation of AAA rupture risk is improved by geometric characteristics of Dmax and Dmax/DAO combined with blood flow pattern and area of low wall shear stress. [ABSTRACT FROM AUTHOR]

Objective To explore the diagnostic accuracy of risk nomogram model based on clinical and CT features for acute complicated appendicitis(ACA). Methods 478 patients with pathologically confirmed acute appendicitis(AA)from December 2020 to December 2022 were retrospectively classified as ACA(acute gangrenous appendicitis,acute perforated appendicitis,appendiceal abscess requiring surgery)and acute uncomplicated appendicitis(AUA:acute simple appendicitis,acute suppurative appendicitis). The clinical features,laboratory findings,and preoperative CT appearance between ACA and AUA groups were compared using single factor analysis. The high-risk factors were screened by multivariate logistic regression analysis and the corresponding nomogram model was constructed. Data from a separate group of 146 patients with AA from January 2023 to August 2023 were used to construct the validation model. Receiver operating characteristic(ROC)curve and decision curve analysis were used for internal validation of model results and compared with traditional Alvarado and the appendicitis inflammatory response(AIR)scoring methods. Results Of the 624 patients,13. 5％(84/624)had ACA. Regression analysis showed that age,duration of appendicitis symptoms,body temperature,percentage of neutrophil,and preoperative CT features were high risk factors for ACA. The nomogram model based on these factors had better diagnostic performance with area under the ROC curve(AUC)of 0. 831(95％CI:0. 783-0. 876),82. 0％sensitivity,72. 2％specificity,and 77. 1％accuracy compared to the Alvarado scoring method(AUC:0. 640,95％CI:0. 585-0. 696;sensitivity:73. 4％;specificity:46. 2％;accuracy:59. 8％)and AIR scoring method(AUC:0. 738,95％CI:0. 585-0. 890;sensitivity:66. 8％;specificity:72. 7％;accuracy:69. 8％). Conclusion Risk nomogram model based on clinical and CT features has high accuracy and reliability in diagnosing ACA. [ABSTRACT FROM AUTHOR]

The goal of this experimental study was to quantify the influence of helical pitch and gantry rotation time on image quality and file size in ultrahigh-resolution photon-counting CT (UHR-PCCT). Cervical and lumbar spine, pelvis, and upper legs of two fresh-frozen cadaveric specimens were subjected to nine dose-matched UHR-PCCT scan protocols employing a collimation of 120 × 0.2 mm with varying pitch (0.3/1.0/1.2) and rotation time (0.25/0.5/1.0 s). Image quality was analyzed independently by five radiologists and further substantiated by placing normed regions of interest to record mean signal attenuation and noise. Effective mAs, CT dose index (CTDIvol), size-specific dose estimate (SSDE), scan duration, and raw data file size were compared. Regardless of anatomical region, no significant difference was ascertained for CTDIvol (p ≥ 0.204) and SSDE (p ≥ 0.240) among protocols. While exam duration differed substantially (all p ≤ 0.016), the lowest scan time was recorded for high-pitch protocols (4.3 ± 1.0 s) and the highest for low-pitch protocols (43.6 ± 15.4 s). The combination of high helical pitch and short gantry rotation times produced the lowest perceived image quality (intraclass correlation coefficient 0.866; 95% confidence interval 0.807–0.910; p < 0.001) and highest noise. Raw data size increased with acquisition time (15.4 ± 5.0 to 235.0 ± 83.5 GByte; p ≤ 0.013). Rotation time and pitch factor have considerable influence on image quality in UHR-PCCT and must therefore be chosen deliberately for different musculoskeletal imaging tasks. In examinations with long acquisition times, raw data size increases considerably, consequently limiting clinical applicability for larger scan volumes. [ABSTRACT FROM AUTHOR]

Objective: To compare the image quality of low-dose CT (LD-CT) with tin filtration of the lumbar spine after metal implants to standard clinical CT, and to evaluate the potential for metal artifact and dose reduction. Materials and methods: CT protocols were optimized in a cadaver torso. Seventy-four prospectively included patients with metallic lumbar implants were scanned with both standard CT (120 kV) and tin-filtered LD-CT (Sn140kV). CT dose parameters and qualitative measures (1 = worst,4 = best) were compared. Quantitative measures included noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and the width and attenuation of the most prominent hypodense metal artifact. Standard CT and LD-CT were assessed for imaging findings. Results: Tin-filtered LD-CT was performed with 60% dose saving compared to standard CT (median effective dose 3.22 mSv (quartile 1–3: 2.73–3.49 mSv) versus 8.02 mSv (6.42–9.27 mSv; p <.001). Image quality of CT and tin-filtered low-dose CT was good with excellent depiction of anatomy, while image noise was lower for CT and artifacts were weaker for tin-filtered LD-CT. Quantitative measures also revealed increased noise for tin-filtered low-dose CT (41.5HU), lower SNR (2) and CNR (0.6) compared to CT (32HU,3.55,1.03, respectively) (all p <.001). However, tin-filtered LD-CT performed superior regarding the width and attenuation of hypodense metal artifacts (2.9 mm and -767.5HU for LD-CT vs. 4.1 mm and -937HU for CT; all p <.001). No difference between methods was observed in detection of imaging findings. Conclusion: Tin-filtered LD-CT with 60% dose saving performs comparable to standard CT in detection of pathology and surgery related complications after lumbar spinal instrumentation, and shows superior metal artifact reduction. [ABSTRACT FROM AUTHOR]

Objective: To determine the value of CT-guided bone core biopsy and investigate factors that affect diagnostic yield and biopsy outcome. Materials and methods: The single-centre retrospective analysis included 447 patients who had CT-guided core biopsy with a 13-G needle (Bonopty®) from January 2016 to December 2021. Histological results or ≥ 6 months of clinical and radiological follow-up served as outcome references. A successful biopsy was classified as "diagnostic" when a definitive diagnosis was made and "adequate" when only the malignant or benign nature of the tumour could be determined. Biopsies were "nondiagnostic" when the nature of the lesion could not be determined. The occult lesions were defined as not seen on CT but visible on other modalities. Results: In 275 (62%) females and 172 (38%) males, the overall success rate was 85% (383 biopsies), with 314 (70%) diagnostic biopsies and 69 (15%) adequate biopsies. There was no relationship between biopsy success and the localisation of the lesion, length of biopsy material, or number of biopsy attempts. The lesions' nature had a statistically significant effect on biopsy success with lytic and mixed lesions having the highest success rate. Occult lesions had the lowest success rate. Conclusion: CT-guided bone core biopsy is an effective method in the workup of musculoskeletal diseases with the highest success rate in lytic and mixed lesions. No apparent relationship was found between biopsy success and biopsy length, number of attempts, or localisation of the lesion. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate and analyze radiomics models based on non-contrast-enhanced computed tomography (CT) and different phases of contrast-enhanced CT in predicting Ki-67 proliferation index (PI) among patients with pathologically confirmed gastrointestinal stromal tumors (GISTs). Methods: A total of 383 patients with pathologically proven GIST were divided into a training set (n = 218, vendor 1) and 2 validation sets (n = 96, vendor 2; n = 69, vendors 3–5). Radiomics features extracted from the most recent non-contrast-enhanced and three contrast-enhanced CT scan prior to pathological examination. Random forest models were trained for each phase to predict tumors with high Ki-67 proliferation index (Ki-67>10%) and were evaluated using the area under the receiver operating characteristic curve (AUC) and other metrics on the validation sets. Results: Out of 107 radiomics features extracted from each phase of CT images, four were selected for analysis. The model trained using the non-contrast-enhanced phase achieved an AUC of 0.792 in the training set and 0.822 and 0.711 in the two validation sets, similar to models trained on different contrast-enhanced phases (p > 0.05). Several relevant features, including NGTDM Busyness and tumor size, remained predictive in non-contrast-enhanced and different contrast-enhanced images. Conclusion: The results of this study indicate that a radiomics model based on non-contrast-enhanced CT matches that of models based on different phases of contrast-enhanced CT in predicting the Ki-67 PI of GIST. GIST may exhibit similar radiological patterns irrespective of the use of contrast agent, and such radiomics features may help quantify these patterns to predict Ki-67 PI of GISTs. Clinical relevance statement: GIST may exhibit similar radiomics patterns irrespective of contrast agent; thus, radiomics models based on non-contrast-enhanced CT could be an alternative for risk stratification in GIST patients with contraindication to contrast agent. Key Points: • Performance of radiomics models in predicting Ki-67 proliferation based on different CT phases is evaluated. • Non-contrast-enhanced CT–based radiomics models performed similarly to contrast-enhanced CT in risk stratification in GIST patients. • NGTDM Busyness remains stable to contrast agents in GISTs in radiomics models. [ABSTRACT FROM AUTHOR]

Objectives: There is a need for CT pulmonary angiography (CTPA) lung segmentation models. Clinical translation requires radiological evaluation of model outputs, understanding of limitations, and identification of failure points. This multicentre study aims to develop an accurate CTPA lung segmentation model, with evaluation of outputs in two diverse patient cohorts with pulmonary hypertension (PH) and interstitial lung disease (ILD). Methods: This retrospective study develops an nnU-Net-based segmentation model using data from two specialist centres (UK and USA). Model was trained (n = 37), tested (n = 12), and clinically evaluated (n = 176) on a diverse 'real-world' cohort of 225 PH patients with volumetric CTPAs. Dice score coefficient (DSC) and normalised surface distance (NSD) were used for testing. Clinical evaluation of outputs was performed by two radiologists who assessed clinical significance of errors. External validation was performed on heterogenous contrast and non-contrast scans from 28 ILD patients. Results: A total of 225 PH and 28 ILD patients with diverse demographic and clinical characteristics were evaluated. Mean accuracy, DSC, and NSD scores were 0.998 (95% CI 0.9976, 0.9989), 0.990 (0.9840, 0.9962), and 0.983 (0.9686, 0.9972) respectively. There were no segmentation failures. On radiological review, 82% and 71% of internal and external cases respectively had no errors. Eighteen percent and 25% respectively had clinically insignificant errors. Peripheral atelectasis and consolidation were common causes for suboptimal segmentation. One external case (0.5%) with patulous oesophagus had a clinically significant error. Conclusion: State-of-the-art CTPA lung segmentation model provides accurate outputs with minimal clinical errors on evaluation across two diverse cohorts with PH and ILD. Clinical relevance: Clinical translation of artificial intelligence models requires radiological review and understanding of model limitations. This study develops an externally validated state-of-the-art model with robust radiological review. Intended clinical use is in techniques such as lung volume or parenchymal disease quantification. Key Points: • Accurate, externally validated CT pulmonary angiography (CTPA) lung segmentation model tested in two large heterogeneous clinical cohorts (pulmonary hypertension and interstitial lung disease). • No segmentation failures and robust review of model outputs by radiologists found 1 (0.5%) clinically significant segmentation error. • Intended clinical use of this model is a necessary step in techniques such as lung volume, parenchymal disease quantification, or pulmonary vessel analysis. [ABSTRACT FROM AUTHOR]

Objective: To assess the applicability of a semiquantitative index for symptomatic minor instability of the lateral elbow (SMILE). Materials and methods: CT arthrograms of consecutive patients with lateral elbow pain who underwent ultrasound-guided CT arthrography at our orthopedic center between April 2019 and May 2022 were included. Images were acquired at 100 kVp and 80 mAs. An expert radiologist (R1) and a radiology resident (R2) retrospectively performed an independent, blinded evaluation of the arthrograms to assess the presence of imaging findings suggestive of elbow instability. The SMILE index (0–8) was obtained adding (I) radial head chondromalacia (0 − 1); (II) humeral capitellum chondromalacia (0 − 1); (III) humeral trochlear ridge chondromalacia (0 − 1); (IV) annular ligament laxity (0 − 2); (V) synovial thickening (0 − 1); (VI) humeroradial joint asymmetry (0 − 1); and (VII) capsular tear (0 − 1). R1 repeated the assessment after 14 days. Cohen's weighted κ statistic and raw concordance were used to appraise reproducibility. Results: Eighty patients (median age 49 years, interquartile range 40–53 years, 49, 61% males) underwent CT arthrography at our center, and 10 (12%) of them underwent bilateral elbow examination, leading to 90 included CT arthrograms. Median SMILE index was 4 (IQR: 2–5) for R1, 4 (IQR: 2–5) for R2, and 4 (IQR: 2–5) for the second assessment by R1. Intra-reader agreement was excellent (κ = 0.94, concordance 87%), while inter-reader agreement was substantial (κ = 0.75, concordance 67%). Conclusion: The proposed SMILE index showed good reproducibility; further studies are warranted to correlate our index with clinical and surgical data. Clinical relevance statement: Our scoring system allows a standardized evaluation of patients with lateral elbow pain and instability suitable for application into clinical practice, complementing the orthopedic surgeon's clinical diagnosis with imaging findings that may aid treatment choices. Key Points: • Lateral elbow pain is often interpreted clinically as lateral epicondylitis, but it can also encompass intra-articular pathology. • The proposed arthrographic index allows comprehensive quantification of lateral elbow pathology with good reproducibility and application times. • Our index provides the orthopedic surgeon with information regarding intra-articular findings, aiding treatment choices. [ABSTRACT FROM AUTHOR]

Objective: To characterize the use and impact of radiation dose reduction techniques in actual practice for routine abdomen CT. Methods: We retrospectively analyzed consecutive routine abdomen CT scans in adults from a large dose registry, contributed by 95 hospitals and imaging facilities. Grouping exams into deciles by, first, patient size, and second, size-adjusted dose length product (DLP), we summarized dose and technical parameters and estimated which parameters contributed most to between-protocols dose variation. Lastly, we modeled the total population dose if all protocols with mean size-adjusted DLP above 433 or 645 mGy-cm were reduced to these thresholds. Results: A total of 748,846 CTs were performed using 1033 unique protocols. When sorted by patient size, patients with larger abdominal diameters had increased dose and effective mAs (milliampere seconds), even after adjusting for patient size. When sorted by size-adjusted dose, patients in the highest versus the lowest decile in size-adjusted DLP received 6.4 times the average dose (1680 vs 265 mGy-cm) even though diameter was no different (312 vs 309 mm). Effective mAs was 2.1-fold higher, unadjusted CTDIvol 2.9-fold, and phase 2.5-fold for patients in the highest versus lowest size-adjusted DLP decile. There was virtually no change in kV (kilovolt). Automatic exposure control was widely used to modulate mAs, whereas kV modulation was rare. Phase was the strongest driver of between-protocols variation. Broad adoption of optimized protocols could result in total population dose reductions of 18.6–40%. Conclusion: There are large variations in radiation doses for routine abdomen CT unrelated to patient size. Modification of kV and single-phase scanning could result in substantial dose reduction. Clinical relevance: Radiation dose-optimization techniques for routine abdomen CT are routinely under-utilized leading to higher doses than needed. Greater modification of technical parameters and number of phases could result in substantial reduction in radiation exposure to patients. Key Points: • Based on an analysis of 748,846 routine abdomen CT scans in adults, radiation doses varied tremendously across patients of the same size and optimization techniques were routinely under-utilized. • The difference in observed dose was due to variation in technical parameters and phase count. Automatic exposure control was commonly used to modify effective mAs, whereas kV was rarely adjusted for patient size. Routine abdomen CT should be performed using a single phase, yet multi-phase was common. • kV modulation by patient size and restriction to a single phase for routine abdomen indications could result in substantial reduction in radiation doses using well-established dose optimization approaches. [ABSTRACT FROM AUTHOR]

Objective To compare the imaging characteristics and qualities of spectral computed tomography (CT) virtual non-contrast (VNC) versus true non-contrast (TNC) scans for pediatric skeletal muscle tumors/tumor-like lesions and explore the accuracy and feasibility of using spectral CT VNC for diagnosing these conditions. Methods A retrospective analysis was conducted for the radiological data of 43 children with skeletal muscle tumors/tumor-like lesions receiving spectral CT plain and dual-phase enhancement scans. Then the raw data were processed into VNCa and VNCv. Also the corresponding normal skeletal muscle and fat on TNC, VNCa and VNCv images were measured. Signal noise ratio (SNR) and contrast noise ratio (CNR) were calculated for comparing the image quality and diagnostic efficacy of three types of images. Results No statistically significant difference existed in CT values of skeletal muscle and skeletal muscle lesions among three types of images (skeletal muscle: F=0.663, P=0.517; skeletal muscle lesions: F=2.139, P=0.122). SNR value of VNCv was significantly higher than that of TNC ( P<0.01). No statistically significant difference existed in CT signs of skeletal muscle tumors/tumor-like lesions between TNC and VNC images ( P>0.05). The subjective scoring consistency of three types of images by two observers was excellent (TNC: κ=0.554; VNCa: κ=0.501; VNCv: κ=0.628). The consistency of CT values of normal skeletal muscle between VNCa, VNCv and TNC images was excellent (average difference: VNCa=1.330 HU, VNCv=0.518 HU). And the consistency of CT values of skeletal muscle lesions between VNCv and TNC images was also decent (average difference=-3.870 HU). Conclusions Spectral CT VNC technology has demonstrated similar image quality and diagnostic value to TNC in diagnosing pediatric skeletal muscle tumors/tumor-like lesions. It may minimize the number of routine plain scans and lower radiation dosage. [ABSTRACT FROM AUTHOR]

To evaluate the potential of quantitative measurements on contrast-enhanced CT (CECT) in differentiating small (≤4 cm) clear cell renal cell carcinoma (ccRCC) from benign renal tumors, including fat-poor angiomyolipoma (fpAML) and renal oncocytoma (RO). 244 patients with pathologically confirmed ccRCC (n = 184) and benign renal tumors (fpAML, n = 50; RO, n = 10) were randomly assigned into training cohort (n = 193) and test cohort 1 (n = 51), while external test cohort 2 (n = 50) was from another hospital. Quantitative parameters were obtained from CECT (unenhanced phase, UP; corticomedullary phase, CMP; nephrographic phase, NP; excretory phase, EP) by measuring attenuation of renal mass and cortex and subsequently calculated. Univariable and multivariable logistic regression analyses were performed to evaluate the association between these parameters and ccRCC. Finally, the constructed models were compared with radiologists' diagnoses. In univariable analysis, UP-related parameters, particularly UP C-T (cortex minus tumor attenuation on UP), demonstrated AUC of 0.766 in training cohort, 0.901 in test cohort 1, 0.805 in test cohort 2. The heterogeneity-related parameter SD (standard deviation) showed AUC of 0.781, 0.834, and 0.875 respectively. In multivariable analysis, model 1 incorporating UP C-T , NP C-T (cortex minus tumor attenuation on NP), CMP T -UP T (tumor attenuation on CMP minus UP), and SD yielded AUC of 0.866, 0.923, and 0.949 respectively. When compared with radiologists, multivariate models demonstrated higher accuracy (0.800–0.860) and sensitivity (0.794–0.971) than radiologists' assessments (accuracy: 0.700–0.720, sensitivity: 0.588–0.706). Quantitative measurements on CECT, particularly UP- and heterogeneity-related parameters, have potential to discriminate ccRCC and benign renal tumors (fpAML, RO). [ABSTRACT FROM AUTHOR]

Objectives: To analyze the diagnostic performance and prognostic value of CT-defined visceral pleural invasion (CT-VPI) in early-stage lung adenocarcinomas. Methods: Among patients with clinical stage I lung adenocarcinomas, half of patients were randomly selected for a diagnostic study, in which five thoracic radiologists determined the presence of CT-VPI. Probabilities for CT-VPI were obtained using deep learning (DL). Areas under the receiver operating characteristic curve (AUCs) and binary diagnostic measures were calculated and compared. Inter-rater agreement was assessed. For all patients, the prognostic value of CT-VPI by two radiologists and DL (using high-sensitivity and high-specificity cutoffs) was investigated using Cox regression. Results: In 681 patients (median age, 65 years [interquartile range, 58–71]; 382 women), pathologic VPI was positive in 130 patients. For the diagnostic study (n = 339), the pooled AUC of five radiologists was similar to that of DL (0.78 vs. 0.79; p = 0.76). The binary diagnostic performance of radiologists was variable (sensitivity, 45.3–71.9%; specificity, 71.6–88.7%). Inter-rater agreement was moderate (weighted Fleiss κ, 0.51; 95%CI: 0.43–0.55). For overall survival (n = 680), CT-VPI by radiologists (adjusted hazard ratio [HR], 1.27 and 0.99; 95%CI: 0.84–1.92 and 0.63–1.56; p = 0.26 and 0.97) or DL (HR, 1.44 and 1.06; 95%CI: 0.86–2.42 and 0.67–1.68; p = 0.17 and 0.80) was not prognostic. CT-VPI by an attending radiologist was prognostic only in radiologically solid tumors (HR, 1.82; 95%CI: 1.07–3.07; p = 0.03). Conclusion: The diagnostic performance and prognostic value of CT-VPI are limited in clinical stage I lung adenocarcinomas. This feature may be applied for radiologically solid tumors, but substantial reader variability should be overcome. Clinical relevance statement: Although the diagnostic performance and prognostic value of CT-VPI are limited in clinical stage I lung adenocarcinomas, this parameter may be applied for radiologically solid tumors with appropriate caution regarding inter-reader variability. Key Points: • Use of CT-defined visceral pleural invasion in clinical staging should be cautious, because prognostic value of CT-defined visceral pleural invasion remains unexplored. • Diagnostic performance and prognostic value of CT-defined visceral pleural invasion varied among radiologists and deep learning. • Role of CT-defined visceral pleural invasion in clinical staging may be limited to radiologically solid tumors. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the image quality and lesion conspicuity of the deep learning image reconstruction (DLIR) algorithm compared with standard image reconstruction algorithms on abdominal enhanced computed tomography (CT) scanning with a wide range of body mass indexes (BMIs). Methods: A total of 112 participants who underwent contrast-enhanced abdominal CT scans were divided into three groups according to BMIs: the 80-kVp group (BMI ≤ 23.9 kg/m2), 100-kVp group (BMI 24–28.9 kg/m2), and 120-kVp group (BMI ≥ 29 kg/m2). All images were reconstructed using filtered back projection (FBP), adaptive statistical iterative reconstruction-V of 50% level (IR), and DLIR at low, medium, and high levels (DL, DM, and DH, respectively). Subjective noise, artifact, overall image quality, and low- and high-contrast hepatic lesion conspicuity were all graded on a 5-point scale. The CT attenuation value (in HU), image noise, and contrast-to-noise ratio (CNR) were quantified and compared. Results: DM and DH improved the qualitative and quantitative parameters compared with FBP and IR for all three BMI groups. DH had the lowest image noise and highest CNR value, while DM had the highest subjective overall image quality and low- and high-contrast lesion conspicuity scores for the three BMI groups. Based on the FBP, the improvement in image quality and lesion conspicuity of DM and DH images was greater in the 80-kVp group than in the 100-kVp and 120-kVp groups. Conclusion: For all BMIs, DLIR improves both image quality and hepatic lesion conspicuity, of which DM would be the best choice to balance both. Clinical relevance statement: The study suggests that utilizing DLIR, particularly at the medium level, can significantly enhance image quality and lesion visibility on abdominal CT scans across a wide range of BMIs. Key Points: • DLIR improved the image quality and lesion conspicuity across a wide range of BMIs. • DLIR at medium level had the highest subjective parameters and lesion conspicuity scores among all reconstruction levels. • On the basis of the FBP, the 80-kVp group had improved image quality and lesion conspicuity more than the 100-kVp and 120-kVp groups. [ABSTRACT FROM AUTHOR]

Objective: Quantify the relationship between CT acquisition parameters and radiation dose, how often parameters are adjusted in real-world practice, and their degree of contribution to real-world dose distribution. Identify discrepancies between parameters that are impactful in theory and impactful in practice. Methods: This study analyses 1.3 million consecutive adult routine abdomen exams performed between November 2015 and Jan 2021 included in the University of California, San Francisco International CT Dose Registry of 155 institutions. We calculated geometric standard deviation (gSD) for five parameters (kV, mAs, spiral pitch, number of phases, scan length) to assess variation in practice. A Gaussian mixed regression model was performed to predict the radiation dose-length product (DLP) using the parameters. Three conceptualizations of "impact" were computed for each parameter. To reflect the theoretical impact, we predict the increase in DLP per 10% (and 15%) increase in the parameter. To reflect the real-world practical impact, we predict the increase in DLP per gSD increase in the parameter. Results: Among studied examinations, mAs, number of phases, and scan length were frequently manipulated (gSD 1.52–1.70); kV was rarely manipulated (gSD 1.07). Theoretically, kV is the most impactful parameter (29% increase in DLP per 10% increase in kV, versus 5–9% increase for other parameters). In real-world practice, kV is less impactful; for each gSD increase in kV, the DLP increases by 20%, versus 22–69% for other parameters. Conclusion: Despite the potential impact of kV on radiation dose, this parameter is rarely manipulated in common practice and this potential remains untapped. Clinical relevance statement: CT beam energy (kV) modulation has the potential to strongly reduce radiation over-dosage to the patient, theoretically more so than similar degrees of modulation in other CT acquisition parameters. Despite this, beam energy modulation rarely occurs in practice, leaving its potential untapped. Key Points: • The relationship between CT acquisition parameter selection and radiation dose roughly coincided with established theoretical understanding. • CT acquisition parameters differ from each other in frequency and magnitude of manipulation, with beam energy (kV) being rarely manipulated. • Beam energy (kV) has the potential to substantially impact radiation dose, but because it is rarely manipulated, it is the least impactful CT acquisition parameter affecting radiation dose in practice. [ABSTRACT FROM AUTHOR]

Objectives: CT reconstruction algorithms affect radiomics reproducibility. In this study, we evaluate the effect of deep learning–based image conversion on CT reconstruction algorithms. Methods: This study included 78 hepatocellular carcinoma (HCC) patients who underwent four-phase liver CTs comprising non-contrast, late arterial (LAP), portal venous (PVP), and delayed phase (DP), reconstructed using both filtered back projection (FBP) and advanced modeled iterative reconstruction (ADMIRE). PVP images were used to train a convolutional neural network (CNN) model to convert images from FBP to ADMIRE and vice versa. LAP, PVP, and DP images were used for validation and testing. Radiomic features were extracted for each patient with a semi-automatic segmentation tool. We used concordance correlation coefficients (CCCs) to evaluate the radiomics reproducibility for original FBP (oFBP) vs. original ADMIRE (oADMIRE), oFBP vs. converted FBP (cFBP), and oADMIRE vs. converted ADMIRE (cADMIRE). Results: In the test group including 30 patients, the CCC and proportion of reproducible features (CCC ≥ 0.85) for oFBP vs. oADMIRE were 0.65 and 32.9% (524/1595) for LAP, 0.65 and 35.9% (573/1595) for PVP, and 0.69 and 43.8% (699/1595) for DP. For oFBP vs. cFBP, the values increased to 0.92 and 83.9% (1339/1595) for LAP, 0.89 and 71.0% (1133/1595) for PVP, and 0.90 and 79.7% (1271/1595) for DP. Similarly, for oADMIRE vs. cADMIRE, the values increased to 0.87 and 68.1% (1086/1595) for LAP, 0.91 and 82.1% (1309/1595) for PVP, and 0.89 and 76.2% (1216/1595) for DP. Conclusions: CNN-based image conversion between CT reconstruction algorithms improved the radiomics reproducibility of HCCs. Clinical relevance statement: This study demonstrates that using a CNN-based image conversion technique significantly improves the reproducibility of radiomic features in HCCs, highlighting its potential for enhancing radiomics research in HCC patients. Key Points: Radiomics reproducibility of HCC was improved via CNN-based image conversion between two different CT reconstruction algorithms. This is the first clinical study to demonstrate improvements across a range of radiomic features in HCC patients. This study promotes the reproducibility and generalizability of different CT reconstruction algorithms in radiomics research. [ABSTRACT FROM AUTHOR]

Objectives: To determine if current clinical use of iodine contrast media (ICM) for computerised tomography (CT) increases the risk of acute kidney injury (AKI) and long-term decline in renal function in patients treated in intensive care. Methods: A retrospective bi-centre cohort study was performed with critically ill subjects undergoing either ICM-enhanced or unenhanced CT. AKI was defined and staged based on the Kidney Disease Improve Global Outcome AKI criteria, using both creatinine and urine output criteria. Follow-up plasma creatinine was recorded three to six months after CT to assess any long-term effects of ICM on renal function. Results: In total, 611 patients were included in the final analysis, median age was 65.0 years (48.0–73.0, quartile 1–quartile 3 (IQR)) and 62.5% were male. Renal replacement therapy was used post-CT in 12.9% and 180-day mortality was 31.2%. Plasma creatinine level on day of CT was 100.0 µmol/L (66.0–166.5, IQR) for non-ICM group and 77.0 µmol/L (59.0–109.0, IQR) for the ICM group. The adjusted odds ratio for developing AKI if the patient received ICM was 1.03 (95% confidence interval 0.64–1.66, p = 0.90). No significant association between ICM and increase in plasma creatinine at long-term follow-up was found, with an adjusted effect size of 2.92 (95% confidence interval − 6.52–12.36, p = 0.543). Conclusions: The results of this study do not indicate an increased risk of AKI or long-term decline in renal function when ICM is used for enhanced CT in patients treated at intensive care units. Clinical relevance statement: Patients treated in intensive care units had no increased risk of acute kidney injury or persistent decline in renal function after contrast-enhanced CT. This information underlines the need for a proper risk-reward assessment before denying patients a contrast-enhanced CT. Key Points: • Iodine contrast media is considered a risk factor for the development of acute kidney injury. • Patients receiving iodine contrast media did not have an increased incidence of acute kidney injury or persistent decline in renal function. • A more clearly defined risk of iodine contrast media helps guide clinical decisions whether to perform contrast-enhanced CTs or not. [ABSTRACT FROM AUTHOR]

Introduction: Urolithiasis is frequently followed up with a low‐dose computed tomography of the kidneys ureters and bladder (LD‐CTKUB) with doses typically less than 3 millisieverts. Although X‐ray is a lower dose (0.5–1.1 mSv) alternative for follow up, it has lower diagnostic accuracy and is limited to radiopaque calculi. This study aims to compare the diagnostic accuracy of sub‐millisievert ultra‐low dose CT (ULD‐CTKUB) against X‐ray KUB for the follow up of urolithiasis when both are compared against the standard of care of a low‐dose CT KUB (LD‐CTKUB). Methods: This prospective study included patients with a known diagnosis of urolithiasis on prior CTKUB presenting for follow up. Each patient underwent a repeat reference LD‐CTKUB, ULD‐CTKUB and X‐ray KUB. All imaging studies were interpreted by three readers. The radiation dose and quantitative noise was calculated for each CT. Both CT and X‐ray were assessed for the presence, number and size of all calculi ≥2 mm. Results: A total of 58 patients were included in this study. LD‐CTKUB identified 197 calculi. ULD‐CTKUB in our study had a mean effective dose of 0.5 mSv compared to X‐ray KUB where doses range in the literature from 0.5 to 1.1 mSv. Per‐patient pooled analysis for intrarenal calculi when comparing ULD‐CTKUB versus X‐ray KUB against a reference LD‐CTKUB found a sensitivity of 90% versus 67% (P < 0.01) and specificity of 93% versus 98% (P = 0.18) respectively. For ureteric calculi, the sensitivity was 67% versus 33% (P < 0.01) and specificity 94% versus 94% (P = 1.00) respectively. Per‐stone pooled analysis detection rate was 79% for ULD‐CTKUB versus 48% for X‐ray (P < 0.01) when each was compared to the reference LD‐CTKUB. Interobserver agreement was high for intrarenal calculi and moderate for ureteric calculi. Conclusion: Sub‐millisievert ULD‐CTKUB had lower doses and higher sensitivity than X‐ray in patients requiring follow up of known urolithiasis. [ABSTRACT FROM AUTHOR]

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Objective: Body composition assessment derived from cross-sectional imaging has shown promising results as a prognostic biomarker in several tumor entities. Our aim was to analyze the role of low skeletal muscle mass (LSMM) and fat areas for prognosis of dose-limiting toxicity (DLT) and treatment response in patients with primary central nervous system lymphoma (PCNSL). Methods: Overall, 61 patients (29 female patients, 47.5%) with a mean age of 63.8 ± 12.2 years, range 23–81 years, were identified in the data base between 2012 and 2020 with sufficient clinical and imaging data. Body composition assessment, comprising LSMM and visceral and subcutaneous fat areas, was performed on one axial slice on L3-height derived from staging computed tomography (CT) images. DLT was assessed during chemotherapy in clinical routine. Objective response rate (ORR) was measured on following magnetic resonance images of the head accordingly to the Cheson criteria. Results: Twenty-eight patients had DLT (45.9%). Regression analysis revealed that LSMM was associated with objective response, OR = 5.19 (95% CI 1.35–19.94, p = 0.02) (univariable regression), and OR = 4.23 (95% CI 1.03- 17.38, p = 0.046) (multivariable regression). None of the body composition parameters could predict DLT. Patients with normal visceral to subcutaneous ratio (VSR) could be treated with more chemotherapy cycles compared to patients with high VSR (mean, 4.25 vs 2.94, p = 0.03). Patients with ORR had higher muscle density values compared to patients with stable and/or progressive disease (34.46 ± vs 28.18 ± HU, p = 0.02). Conclusions: LSMM is strongly associated with objective response in patients with PCNSL. Body composition parameters cannot predict DLT. Clinical relevance statement: Low skeletal muscle mass on computed tomography (CT) is an independent prognostic factor of poor treatment response in central nervous system lymphoma. Analysis of the skeletal musculature on staging CT should be implemented into the clinical routine in this tumor entity. Key Points: • Low skeletal muscle mass is strongly associated with the objective response rate. • No body composition parameters could predict dose-limiting toxicity. [ABSTRACT FROM AUTHOR]

Objectives: To develop a contrast-enhanced CT (CECT) radiomics-based model to identify locoregionally advanced nasopharyngeal carcinoma (LA-NPC) patients who would benefit from deintensified chemoradiotherapy. Methods: LA-NPC patients who received low-dose concurrent cisplatin therapy (cumulative: 150 mg/m2), were randomly divided into training and validation groups. 107 radiomics features based on the primary nasopharyngeal tumor were extracted from each pre-treatment CECT scan. Through Cox regression analysis, a radiomics model and patients' corresponding radiomics scores were created with predictive independent radiomics features. T stage (T) and radiomics score (R) were compared as predictive factors. Combining the N stage (N), a clinical model (T + N), and a substitution model (R + N) were constructed. Results: Training and validation groups consisted of 66 and 33 patients, respectively. Three significant independent radiomics features (flatness, mean, and gray level non-uniformity in gray level dependence matrix (GLDM-GLN)) were found. The radiomics score showed better predictive ability than the T stage (concordance index (C-index): 0.67 vs. 0.61, AUC: 0.75 vs. 0.60). The R + N model had better predictive performance and more effective risk stratification than the T + N model (C-index: 0.77 vs. 0.68, AUC: 0.80 vs. 0.70). The R + N model identified a low-risk group as deintensified chemoradiotherapy candidates in which no patient developed progression within 3 years, with 5-year progression-free survival (PFS) and overall survival (OS) both 90.7% (hazard ratio (HR) = 4.132, p = 0.018). Conclusion: Our radiomics-based model combining radiomics score and N stage can identify specific LA-NPC candidates for whom de-escalation therapy can be performed without compromising therapeutic efficacy. Clinical relevance statement: Our study shows that the radiomics-based model (R + N) can accurately stratify patients into different risk groups, with satisfactory prognosis in the low-risk group when treated with low-dose concurrent chemotherapy, providing new options for individualized de-escalation strategies. Key Points: • A radiomics score, consisting of 3 predictive radiomics features (flatness, mean, and GLDM-GLN) integrated with the N stage, can identify specific LA-NPC populations for deintensified treatment. • In the selection of LA-NPC candidates for de-intensified treatment, radiomics score extracted from primary nasopharyngeal tumors based on CECT can be superior to traditional T stage classification as a predictor. [ABSTRACT FROM AUTHOR]

Objectives: To explore the added value of arterial enhancement fraction (AEF) derived from dual-energy computed tomography CT (DECT) to conventional image features for diagnosing cervical lymph node (LN) metastasis in papillary thyroid cancer (PTC). Methods: A total of 273 cervical LNs (153 non-metastatic and 120 metastatic) were recruited from 92 patients with PTC. Qualitative image features of LNs were assessed. Both single-energy CT (SECT)–derived AEF (AEFS) and DECT-derived AEF (AEFD) were calculated. Correlation between AEFD and AEFS was determined using Pearson's correlation coefficient. Multivariate logistic regression analysis with the forward variable selection method was used to build three models (conventional features, conventional features + AEFS, and conventional features + AEFD). Diagnostic performances were evaluated using receiver operating characteristic (ROC) curve analyses. Results: Abnormal enhancement, calcification, and cystic change were chosen to build model 1 and the model provided moderate diagnostic performance with an area under the ROC curve (AUC) of 0.675. Metastatic LNs demonstrated both significantly higher AEFD (1.14 vs 0.48; p < 0.001) and AEFS (1.08 vs 0.38; p < 0.001) than non-metastatic LNs. AEFD correlated well with AEFS (r = 0.802; p < 0.001), and exhibited comparable performance with AEFS (AUC, 0.867 vs 0.852; p = 0.628). Combining CT image features with AEFS (model 2) and AEFD (model 3) could significantly improve diagnostic performances (AUC, 0.865 vs 0.675; AUC, 0.883 vs 0.675; both p < 0.001). Conclusions: AEFD correlated well with AEFS, and exhibited comparable performance with AEFS. Integrating qualitative CT image features with both AEFS and AEFD could further improve the ability in diagnosing cervical LN metastasis in PTC. Clinical relevance statement: Arterial enhancement fraction (AEF) values, especially AEF derived from dual-energy computed tomography, can help to diagnose cervical lymph node metastasis in patients with papillary thyroid cancer, and complement conventional CT image features for improved clinical decision making. Key Points: • Metastatic cervical lymph nodes (LNs) demonstrated significantly higher arterial enhancement fraction (AEF) derived from dual-energy computed tomography (DECT) and single-energy CT (SECT)–derived AEF (AEFS) than non-metastatic LNs in patients with papillary thyroid cancer. • DECT-derived AEF (AEFD) correlated significantly with AEFS, and exhibited comparable performance with AEFS. • Integrating qualitative CT images features with both AEFS and AEFD could further improve the differential ability. [ABSTRACT FROM AUTHOR]