Tomography

Objective: Non-contrast computed tomography (CT) remains the gold standard for diagnosing ureteral stones, with excellent sensitivity and specificity. However, reliance on CT alone raises concerns regarding cumulative radiation exposure, particularly in recurrent stone formers. Clinical scoring systems such as CHOKAI, STONE, and modified STONE have been developed to provide practical bedside tools for diagnostic decision-making. This study prospectively compared these three clinical scores for their ability to predict urinary-stone disease in the emergency department. Study Design: Prospective study. Methods and Duration of the Study: Between 6 August 2024 and 15 February 2025, 130 consecutively enrolled adults with flank pain underwent bedside scoring and reference-standard non-contrast CT. Associations were analysed with Chi-Square Tests and multivariable logistic regression. Model calibration was assessed with the Hosmer–Lemeshow test; overall accuracy was calculated. Results: When the variables used in different stone scoring formulas were compared according to the computer tomography results, there was a statistically significant difference (p < 0.01) between patients with and without a history of stone and hydronephrosis. Patients with nausea, history of stone, and hydronephrosis were 11, 4.2, and 5 times more highly to have a stone on computer tomography than those without, respectively. Conclusions: In this Turkish cohort, CHOKAI and modified STONE demonstrated superior predictive performance compared to the original STONE score. These findings suggest that clinical scoring systems, when incorporating predictors such as nausea, prior stone history, and hydronephrosis, may serve as practical alternatives to CT-first diagnostic approaches. Multicenter validation studies are required before routine clinical adoption. Full article

Background/Objectives: The recent development of four-dimensional X-ray velocimetry (4DXV) technology (three-dimensional space and time) provides a unique opportunity to obtain preclinical quantitative functional lung images. Only single-scan measurements in non-survival studies have been obtained to date; thus, methodologies enabling animal survival for repeated imaging to be accomplished over weeks or months from the same animal would establish new opportunities for the assessment of pathophysiology drivers and treatment response in advanced preclinical drug-screening efforts. Methods: An anesthesia protocol developed for animal recovery to allow for repetitive, longitudinal scanning of individual animals over time. Test–retest imaging scans from the lungs of healthy mice were performed over 8 weeks to assess the repeatability of scanner-derived quantitative imaging metrics and variability. Results: Using a murine model of fibroproliferative lung disease, this longitudinal scanning approach captured heterogeneous progressive changes in pulmonary function, enabling the visualization and quantitative measurement of averaged whole lung metrics and spatial/regional change. Radiation dosimetry studies evaluated the effects of imaging acquisition protocols on X-ray dosage to further adapt protocols for the minimization of radiation exposure during repeat imaging sessions using these newly developed image acquisition protocols. Conclusions: Overall, we have demonstrated that the 4DXV advanced imaging scanner allows for repeat measurements from the same animal over time to enable the high-resolution, noninvasive mapping of quantitative lung airflow dysfunction in mouse models with heterogeneous pulmonary disease. The animal anesthesia and image acquisition protocols described will serve as the foundation on which further applications of the 4DXV technology can be used to study a diverse array of murine pulmonary disease models. Together, 4DXV provides a novel and significant advancement for the longitudinal, noninvasive interrogation of pulmonary disease to assess spatial/regional disease initiation, progression, and response to therapeutic interventions. Full article

Breast cancer detection remains a significant challenge, with traditional mammography presenting barriers such as discomfort, radiation exposure, high false-positive rates, and financial burden. Moreover, younger women frequently fall outside routine mammographic screening guidelines, leaving critical gaps in early detection. Objectives: This study investigates the potential of quantitative transmission breast acoustic computed tomography scanner imaging (QT3D) as an innovative, non-invasive imaging modality for characterizing and evaluating breast masses. Methods: A comparative analysis between QT3D imaging and magnetic resonance imaging (MRI) was conducted in a cohort of patients with biopsy-proven benign or malignant breast lesions, comparing key metrics in quantifying breast masses for the purposes of breast mass characterization. Results: The findings in this study highlight its capability in identifying relatively small tumors, multiple lesions, satellite lesions, intraductal extensions, and calcifications, in addition to offering valuable diagnostic insights. Conclusions: This work is a first step toward studies essential for confirming its clinical feasibility, establishing its role in breast cancer tumor characterization, and potentially improving patient outcomes. Full article

Background/Objectives: Children with adolescent idiopathic scoliosis (AIS) require repeated imaging, primarily standing spine radiography, while CT may be required for surgical planning, resulting in higher radiation exposure. Spectral shaping using a tin filter can reduce radiation dose in non-contrast chest CT. This study evaluated the efficacy of spectral shaping using a tin filter for reducing radiation dose in CT imaging in AIS and its impact on image quality. Methods: We retrospectively analyzed 51 AIS patients who underwent spine CT between February 2017 and March 2022, and divided them into two groups: normal-dose CT (NDCT) and low-dose CT with spectral shaping with a tin filter (LDCT). Radiation doses and image quality were compared between the groups. Radiation dose was recorded as the volume CT dose index (CTDIvol) and the dose length product emitted from the device, and effective and equivalent doses obtained from simulations. Results: The use of spectral shaping with a tin filter resulted in a 75% reduction in radiation dose compared to conventional CT without any reduction in image quality. Conclusions: Spectral shaping CT with a tin filter can substantially reduce radiation dose while maintaining image quality. It may be considered a safer alternative to conventional CT when clinically indicated in AIS patients. Full article

Objective: This study aimed to evaluate the hepatic volume, iodine concentration, and extracellular volume (ECV) of each hepatic segment in cirrhotic patients using three-dimensional (3D) volumetric iodine mapping of the liver segment derived from contrast-enhanced dual-energy CT (DECT) superimposed on extracted color-coded CT liver segments in comparison with non-cirrhotic patients. Methods: The study population consisted of 66 patients, 34 with cirrhosis and 32 without cirrhosis. Using 3D volumetric iodine mapping of the liver segment derived from contrast-enhanced DECT superimposed on extracted color-coded CT liver segments, the volume and iodine concentration of each hepatic segment in the portal venous phase (PVP) and equilibrium phase (EP), the difference in iodine concentration between PVP and EP (ICPVP-liver—ICEP-liver), and ECV fractions were compared between cirrhotic and non-cirrhotic groups. Results: The iodine concentration was not significantly different in all hepatic segments between the cirrhotic and non-cirrhotic groups. Conversely, the difference in iodine concentration between PVP and EP (ICPVP-liver—ICEP-liver) was significantly smaller in the cirrhosis group than in the non-cirrhosis group for all hepatic segments (p < 0.001). The ECV fraction of the left medial segment was significantly higher in the cirrhosis group than in the non-cirrhotic group ([26.4 ± 7.6] vs. [23.1 ± 5.1]; p < 0.05). Conclusions: The decreased difference in iodine concentration between PVP and EP calculated from 3D volumetric iodine mapping of the liver segment using DECT may be a clinically useful indicator for evaluating patients with compensated cirrhosis, suggesting a combined effect of a reduced portal venous flow and increased interstitial space associated with fibrosis. Full article

Purpose: This study aimed to evaluate the diagnostic performance of GPT-4 Omni (GPT-4o) in emergency abdominal computed tomography (CT) cases compared to radiology residents with varying levels of experience, under conditions that closely mimic real clinical scenarios. Material and Methods: A total of 45 emergency cases were categorized into three levels of difficulty (easy, moderate, and difficult) and evaluated by six radiology residents with varying levels of experience (limited: R1–R2; intermediate: R3–R4; advanced: R5–R6) and GPT-4o. Cases were presented sequentially to both groups with consistent clinical data and CT images. Each case included 4 to 7 CT slice images, resulting in a total of 243 images. The participants were asked to provide the single most likely diagnosis for each case. GPT-4o’s CT image interpretation performance without clinical data and hallucination rate were evaluated. Results: Overall diagnostic accuracy rates were 76% for R1–R2, 89% for R3, 82% for R4–R5, 84% for R6, and 82% for GPT-4o. Case difficulty significantly affected the diagnostic accuracy for both the residents and GPT-4o, with accuracy decreasing as case complexity increased (p < 0.001). No statistically significant differences in diagnostic accuracy were found between GPT-4o and the residents, regardless of the experience level or case difficulty (p > 0.05). GPT-4o demonstrated a hallucination rate of 75%. Conclusions: GPT-4o demonstrated a diagnostic accuracy comparable to that of radiology residents in emergency abdominal CT cases. However, its dependence on structured prompts and high hallucination rate indicates the need for further optimization before clinical integration. Full article

Background: Small bowel obstruction (SBO) accounts for 12–16% of surgical hospital admissions and can lead to complications such as bowel ischemia. Traditional management requires transporting patients to the Radiology Department (RD) for a fluoroscopic small bowel series, occupying resources and time. This study evaluates the efficacy and efficiency of the Small Bowel Challenge Exam, a bedside alternative. Methods: A retrospective analysis was performed on 85 SBO patients from January 2018 to December 2023 at an academic tertiary care facility, comparing the traditional fluoroscopic series (37 patients) to the bedside Small Bowel Challenge Exam (48 patients). Key metrics analyzed included hospital resource utilization, overall costs, and length of stay. Results: Gender and race distributions were similar between groups (p = 0.268 and p = 0.808, respectively). Median total costs were lower in the challenge group (USD 1243 vs. USD 1472; p = 0.1229), significantly so when excluding CT scan costs (USD 993.5 vs. USD 1270; p = 0.0500). Core costs also significantly favored the challenge group (USD 389.6 vs. USD 615; p < 0.0001). Length of stay and variable costs showed no significant differences (p = 0.3846 and p = 0.8065, respectively). Additional imaging frequencies were comparable (p = 0.96 for CT scans; p = 0.97 for XR exams). Conclusions: The Small Bowel Challenge Exam reduces certain costs and logistical burdens without prolonging length of stay, suggesting more efficient use of hospital resources. Further research is recommended to evaluate broader implementation and long-term impacts. Full article

Background/Objectives: Diffusion-weighted imaging (DWI) of the liver is prone to cardiac motion-induced signal dropout, which can be reduced using flow-compensated (FloCo) instead of monopolar (MP) diffusion encodings. This study examined differences in lesion detection capabilities between FloCo and MP DWI and whether visibility depends on lesion size and position. Methods: Forty patients with at least one known or suspected focal liver lesion (FLL) underwent FloCo and MP DWI. For both sequences, b = 800 s/mm² images were used to manually segment FLLs, which were then sorted by size and location (liver segment). The number of detected lesions, the sensitivity, and the contrast-to-noise ratio (CNR) were calculated and compared across sequences, sizes, and locations. Results: Significantly more lesions were detected using FloCo DWI compared to MP DWI (1211 vs. 1154; p < 0.001). In total, 1258 unique lesions were detected, 104 of which were identified only by FloCo DWI, and 47 of which only by MP DWI. The sensitivities of FloCo DWI and MP DWI were 96.3% (95% CI: 95.1–97.2%) and 91.7% (95% CI: 90.1–93.2%), respectively. The largest additional lesion found with only one of the two sequences measured 10.9 mm in FloCo DWI and 8.2 mm in MP DWI. In relative numbers, more additional FloCo lesions were found in the left liver lobe than in the right liver lobe (6.4% vs. 3.5%). The lesion CNR was significantly higher for FloCo DWI than for MP DWI (p < 0.05) for all evaluated size intervals and liver segments. Conclusions: FloCo DWI appears to enhance the detectability of FLLs compared to MP DWI, particularly for small liver lesions and lesions in the left liver lobe. Full article

Introduction and Objectives: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been used as a gold standard in diagnosing and following pituitary microadenomas. However, the use of gadolinium-based contrast agents (GBCAs) involves a potential risk of long-term retention in tissues and adverse reactions. This study aimed to evaluate the sensitivity of non-contrast MRI (T1W and T2W sequences) in follow-up imaging of pituitary microadenomas, attempting a comparison with DCE-MRI, assessing tumor stability over time. Materials and methods: We retrospectively reviewed 300 pituitary MRI scans between 2020 and 2024. Included were patients with confirmed microadenomas (≤10 mm). Non-contrast (T1W/T2W) and DCE-MRI sequences were analyzed by an experienced radiologist blinded to any clinical information. Detection rates and changes in tumor size were evaluated. Results: Detection rates for 79 microadenomas were 55.7% for T1W, 70.9% for T2W, and 88.6% for DCE-MRI. There was no significant tumor growth during the follow-up (mean size 4.80 ± 2.3 mm vs. 4.81 ± 2.4 mm, p > 0.5). Conclusions: While still more sensitive for the primary diagnosis, the non-contrast MRI was able to visualize the majority of detected microadenomas, and significant growth was ruled out, thus supporting the case to omit gadolinium from follow-up imaging in stable cases. This may translate to lower costs and decreased patient risk from contrast-related hazards. Full article

Background/Objectives: To develop and validate deep learning-based models for detecting significant steno-occlusion (SSO)—defined as luminal narrowing greater than 50%—of the femoropopliteal arteries using maximum intensity projection (MIP) images from lower extremity CT angiography (CTA). Methods: This retrospective study utilized MIP images of lower extremity CTA performed between January 2021 and December 2023 for internal model development. Deep learning-based models were developed sequentially to diagnose SSO: screening with single anteroposterior image, followed by four-segment rotational analysis that divided each femoropopliteal artery into four segments and incorporated multi-angle images. Given the cropped images and the shape of stenosis, models were trained to classify the presence of SSO. A temporal validation dataset comprised MIP images from lower extremity CTA performed between January and June 2024. Results: In total, 56,496 segment images from 642 patients (mean age: 68.2 ± 13.5 years; 472 men) were included in the internal dataset. In the single-image analysis, RDNet achieved the highest mean AUC of 0.886 for SSO detection. In the four-segment rotational analysis, RDNet also demonstrated the highest mean AUC, reaching 0.964 in both half-set and full-set approaches. While RDNet recorded the highest mean AUC, all other models showed improved AUCs as the number of input images increased (p < 0.05). In the temporal validation dataset, RDNet again achieved the highest mean AUC (0.959) in the half-set analysis. Conclusions: The deep learning-based model, particularly RDNet, demonstrated excellent performance in detecting SSO of peripheral arteries on MIP images from lower extremity CTA. Full article

Background/Objectives: Several sequences for magnetization transfer contrast (MTC) imaging are available, from indices of MTC ranging from quantitative magnetization transfer (qMT) that yields the macromolecular fraction to simple ratios of signal intensities with and without a magnetization transfer (MT) pulse. Aging muscle undergoes changes including an increase in fibrosis and adipose accompanied by fiber atrophy and loss. The objective is to evaluate five MTC sequences to study age-related differences in muscle tissue composition. Methods: The lower leg (calf) of 15 young (8M/7F, 25.8 ± 3.7 years) and 9 senior subjects (5F/4M, 68.4 ± 3.3 years) was imaged with the following sequences: multi-offset qMT fit to the Ramani and Yarnykh models, single-offset qMT two-parameter fit to the Ramani model, a semi-quantitative MT_sat sequence, magnetization transfer ratio (MTR), and MTR-corrected (MTR_corr) for B1 inhomogeneities. T1 mapping was also performed. Statistical analysis was performed to identify significant age-related and regional (intermuscular) differences. Results: Significant age-related decreases (p < 0.001) in macromolecular fraction (from two-parameter fit), MT_sat, MTR, and MTR_corr were identified. A significant age-related increase in T1 (p < 0.001) was also identified. Pearson correlation coefficients between T1 and MTC indices were weak to moderate but significant. Conclusions: Age-related decreases in MTC may reflect that loss of myofibrillar proteins dominates the increase in collagen content with age. Further, the modest correlation of MTC indices with T1 indicates that all the age-related differences in MTC cannot be explained by an increase in inflammation. The MT_sat sequence was identified as the most clinically relevant in terms of acquisition speed, post-processing simplicity, and ability to identify age-related differences in macromolecular fractions. Full article

Micro-computed tomography (micro-CT) is a commonly used tool for bone evaluation in animal model research. Micro-scale finite element analysis (µFEA) has been proposed to account for different loading scenarios, detailed three-dimensional (3D) bone structure, material properties, and distribution obtained from micro-CT to estimate bone mechanical properties and to predict its potential fracture. The in vivo application of µFEA has been limited to animal models due to the smaller bore size of micro-CT and the long scan time. This narrative review article describes studies that used micro-CT-based µFEA to predict bone mechanical competence, understand bone fracture and remodeling mechanisms, and to evaluate the impacts of the therapeutics, implants, and surgical interventions. Moreover, the concept, limitations, and future potentials of micro-CT-based FEA are discussed. Full article

Background/Objectives: A thorough understanding of spinal anatomy is essential for diagnostic assessment and surgical intervention. Interspinous distance (ISD), neuroforaminal dimensions (NFDs), and disc space height (DSH) have each been studied separately; however, their interrelationship remains unstudied. Given the use of interspinous implants as a minimally invasive treatment for lumbar stenosis and degenerative disc disease, defining these relationships is of growing clinical significance. This study investigates the correlation between ISD and both NFDs and DSH in a normative population and whether ISD varies with demographic factors. Methods: A retrospective chart review was performed on 852 patients who underwent CT imaging of the lumbar spine. ISD was measured from L1 to L5 as the shortest distance between the most caudal tip of the superior spinous process and the inferior spinous process. DSH was measured at the anterior, middle, and posterior margins. NFDs were assessed in axial and sagittal views, including axial width, craniocaudal height, and foraminal area. Statistical analysis assessed correlations between ISD, NFDs, DSH, and demographic variables. Results: No strong correlation was observed between ISD and either NFDs or DSH. Slightly greater correlation was present at L1–L3, weakening at L4–L5, where interspinous implants are most commonly placed. Demographic analysis revealed no consistent relationship between ISD and ethnicity, sex, or BMI. While it may be expected that larger ISD correlates with greater NFDs or DSH, our findings do not support this assumption. Conclusions: ISD does not strongly correlate with NFDs or DSH, and demographic factors do not significantly influence ISD in a healthy population. Full article

Background: The COVID-19 pandemic has claimed thousands of lives worldwide. While infection rates have declined in recent years, emerging variants remain a deadly threat. Accurate diagnosis is critical to curbing transmission and improving treatment outcomes. However, the similarity of COVID-19 symptoms to those of the common cold and flu has spurred the development of automated diagnostic methods, particularly through lung computed-tomography (CT) scan analysis. Methodology: This paper proposes a novel deep learning-based approach for detecting diverse COVID-19 variants using advanced textural feature extraction. The framework employs a dual-channel convolutional neural network (CNN), where one channel processes texture-based features and the other analyzes spatial information. Unlike existing methods, our model dynamically learns textural patterns during training, eliminating reliance on predefined features. A modified local binary pattern (LBP) technique extracts texture data in matrix form, while the CNN’s adaptable internal architecture optimizes the balance between accuracy and computational efficiency. To enhance performance, hyperparameters are fine-tuned using the Adam optimizer and focal loss function. Results: The proposed method is evaluated on two benchmark datasets, COVID-349 and Italian COVID-Set, which include diverse COVID-19 variants. Conclusions: The results demonstrate its superior accuracy (94.63% and 95.47%, respectively), outperforming competing approaches in precision, recall, and overall diagnostic reliability. Full article

Background: Thoracic kyphosis has been increasingly associated with altered intra-abdominal and diaphragmatic dynamics, potentially contributing to gastroesophageal reflux disease (GERD) and hiatal hernia (HH). While previous studies have shown a relationship between spinal deformities and GERD symptoms, these findings have been largely observational, with few morphometric analyses. No prior study has directly quantified the relationship between thoracic curvature and hiatal surface area (HSA) using standardized computed tomography (CT)-based methods. Furthermore, existing studies have typically focused on patients with visible hernias, limiting understanding of early, subclinical anatomical changes. This study addresses this gap by evaluating whether thoracic kyphosis is associated with measurable hiatal enlargement, even in the absence of overt HH. Methods: In this retrospective, single-center study, 100 adult patients (50 with thoracic kyphosis, defined as a Cobb angle of ≥50° and 50 age- and sex-matched controls) underwent multidetector CT (MDCT). Hiatal surface area (HSA) was measured on a standardized oblique axial plane aligned with the diaphragmatic crura. Correlation and multivariable regression analyses were performed to assess relationships between Cobb angle and HSA. Results: The kyphosis group showed significantly larger HSA than controls (5.14 ± 1.31 cm² vs. 3.59 ± 0.74 cm²; p < 0.001). A moderate positive correlation was found between Cobb angle and HSA (r = 0.336, p = 0.017). Multivariable analysis identified the Cobb angle as an independent predictor of HSA (β = 0.028; p = 0.017), while age and sex were not significant predictors. No overt herniation was present in any subject. Conclusions: This is the first CT-based morphometric study to demonstrate that thoracic kyphosis is associated with hiatal enlargement, even in the absence of overt herniation. These findings support the hypothesis that postural spinal deformities may predispose individuals to GERD by structurally remodeling the diaphragmatic hiatus. Full article

Objectives: Point-of-care ultrasound (POCUS) has become an integral part of emergency, intensive care, and perioperative medicine. However, the training and subsequent evaluation of POCUS users are still not standardized. The aim of the study was to develop and validate an assessment tool for POCUS users. Methods: After reviewing the existing literature and a multi-stage expert survey (Delphi method), consensus on twelve items for the assessment tool was reached. To validate the assessment tool, a group of volunteer doctors and medical students performed a POCUS examination using simple linear probe and more complex sector probe techniques. The examination was evaluated by two independent assessors using the created assessment tool. Then, four experts evaluated anonymized recordings of the examinations. We tested the reliability and validity, including internal consistency. Results: A total of 70 examinations were included. Of these, 19 examinations were carried out by physicians and 51 by medical students. A high inter-rater reliability (Cohen’s kappa 0.78 (linear weighted; SEM 0.37; p < 0.001) and Krippendorff’s alpha 0.895) was shown for the evaluation tool. To improve discriminative power and strengthen reliability, the assessment tool was modified using Cronbach’s alpha. Modification resulted in the removal of three items (patient positioning, ultrasound mode selection, and probe selection) from the tool. The mean values of instrument and expert ratings were now 2.62% apart (46.90% instrument vs. 44.29% expert). Pearson’s correlation coefficient between tool and expert ratings showed moderate to high validity (r = 0.69; p < 0.001). Conclusions: The new assessment tool is highly reliable and a valid tool for assessing POCUS skills. It holds strong potential for integration into medical education and training to objectify ultrasound skills. Further studies are required to investigate discriminatory power and transferability to other POCUS algorithms. Full article

This review explores how multimodal foundation models (MFMs) are transforming biliary tract cancer (BTC) research. BTCs are aggressive malignancies with poor prognosis, presenting unique challenges due to difficult diagnostic methods, molecular complexity, and rarity. Importantly, intrahepatic cholangiocarcinoma (iCCA), perihilar cholangiocarcinoma (pCCA), and distal bile duct cholangiocarcinoma (dCCA) represent fundamentally distinct clinical entities, with iCCA presenting as mass-forming lesions amenable to biopsy and targeted therapies, while pCCA manifests as infiltrative bile duct lesions with challenging diagnosis and primarily palliative management approaches. MFMs offer potential to advance research by integrating radiological images, histopathology, multi-omics profiles, and clinical data into unified computational frameworks, with applications tailored to these distinct BTC subtypes. Key applications include enhanced biomarker discovery that identifies previously unrecognizable cross-modal patterns, potential for improving currently limited diagnostic accuracy—though validation in BTC-specific cohorts remains essential—accelerated drug repurposing, and advanced patient stratification for personalized treatment. Despite promising results, challenges such as data scarcity, high computational demands, and clinical workflow integration remain to be addressed. Future research should focus on standardized data protocols, architectural innovations, and prospective validation studies. The integration of artificial intelligence (AI)-based methodologies offers new solutions for these historically challenging malignancies. However, current evidence for BTC-specific applications remains largely theoretical, with most studies limited to proof-of-concept designs or related cancer types. Comprehensive clinical validation studies and prospective trials demonstrating patient benefit are essential prerequisites for clinical implementation. The timeline for evidence-based clinical adoption likely extends 7–10 years, contingent on successful completion of validation studies addressing current evidence gaps. Full article

Objectives: Few studies have reported in vivo measurements of electron density (ED) and effective atomic number (Z_eff) in normal brain tissue. To address this gap, dual-energy computed tomography (DECT)-derived ED and Z_eff maps were used to characterize normal-appearing adult brain tissues, evaluate age-related changes, and investigate correlations with myelin partial volume (V_my) from synthetic magnetic resonance imaging (MRI). Materials and Methods: Thirty patients were retrospectively analyzed. The conventional computed tomography (CT) value (CT_conv), ED, Z_eff, and V_my were measured in the normal-appearing gray matter (GM) and white matter (WM) regions of interest. V_my and DECT-derived parameters were compared between WM and GM. Correlations between V_my and DECT parameters and between age and DECT parameters were analyzed. Results: V_my was significantly greater in WM than in GM, whereas CT_conv, ED, and Z_eff were significantly lower in WM than in GM (all p < 0.001). Z_eff exhibited a stronger negative correlation with V_my (ρ = −0.756) than CT_conv (ρ = −0.705) or ED (ρ = −0.491). ED exhibited weak to moderate negative correlations with age in nine of the 14 regions. In contrast, Z_eff exhibited weak to moderate positive correlations with age in nine of the 14 regions. CT_conv exhibited negligible to insignificant correlations with age: Conclusions: This study revealed distinct GM–WM differences in ED and Z_eff along with opposing age-related changes in these quantities. Therefore, myelin may have substantially contributed to the lower Z_eff observed in WM, which underlies the GM–WM contrast observed on non-contrast-enhanced CT. Full article