Spectral Computed Tomography Scan Research Articles

Coronary atherosclerotic plaque burden and characterization by spectral computed tomography scan in patients with high lipoprotein a and non-hemodynamically significant stenosis

Abstract Introduction Atherosclerotic coronary disease increases morbidity and mortality worldwide. Lipoprotein A (LpA) has emerged as a cardiovascular risk marker, but little is known of its direct influence in plaque volume and composition. Spectral computed tomography (CT) technology allows to characterize coronary plaques with new promising tools. Purpose To evaluate the association of LpA with the extent and composition of non-significant coronary plaques producing stenosis <50%. Methods We prospectively recruited 109 patients referred for noninvasive CT angiography (November 2023-January 2024) with suspected coronary artery disease. 20 had totally/partially non-calcified, non-significant coronary plaques. Plaques were segmented and volume was measured. Their composition was stablished as calcified (>200 UH), lipidic (<60 UH) and fibrous (60-200 UH). Spectral data-based plaque parameters were analyzed, including radiological attenuation on polyenergetic images (CTPI), on virtual low/high monoenergetic images (CT40KeV and CT140KeV, respectively), variation in attenuation across monoenergetic levels (slope40-140 KeV) and Z-effective value. CT scan images were acquired with a 128 detectors dual-layer spectral scan with prospective-retrospective/synchronization. Intravascular iodine-based contrast was administered. LpA was stablished as high (≥25 mg/dL) or low (<25 mg/dL). Results Mean age was 60 ± 11. Cardiovascular risk factor were equally distributed between groups. We analyzed 33 plaques. Total plaque volume was significantly higher in high LpA patients (125.9 mm3 vs 62.1 mm3). There were no differences in plaque composition by LpA (Table). Additionally, spectral data showed significantly higher plaque attenuation on CT140KeV images in high LpA patients (36.07 vs 21.32 HU; p = 0.05). There were no differences for the rest of spectral parameters. Conclusions Plaque volume was higher in patients with non-significant atherosclerotic disease and high LpA, but these plaques showed similar composition in high and low LpA patients. These patients might, therefore, respond to the same conventional treatment event though there is not specific treatment for high LpA yet. Additionally, spectral CT140KeV images could add more precision differentiating these plaques since radiological attenuation in these reconstructions is higher in patients with high LpA.TableFigure

Cadonilimab in combined with gemcitabine and cisplatin in advanced biliary tract cancer (BicureX): A phase II, single-arm clinical trial.

e16158 Background: PD-1 or PD-L1 inhibitors plus chemotherapy as the first-line treatment has been proven to be effective in improving the prognosis of advanced biliary tract cancer (BTC) patients. However, there is still considerable demand for further improvement of BTC patients’ prognosis. This trial aims to evaluate the efficacy and safety of Cadonilimab (PD-1/CTLA-4, a bi-specific antibody) plus gemcitabine and cisplatin for patients with advanced BTC in first -line treatment. Methods: In this phase II, single-arm trial, we will enroll 65 patients with previously untreated, unresectable, locally advanced or metastatic BTC, including intrahepatic or extrahepatic cholangiocarcinoma (ICC/ECC) and gallbladder carcinoma (GBC). Participants received Cadonilimab (10 mg/kg, days 1, every three weeks) plus gemcitabine (1000 mg/m2, days 1, 8, Q3W), and cisplatin (25 mg/m2, days 1, 8, Q3W) for up to eight cycles, followed by Cadonilimab (10 mg/kg, days 1, Q3W) until disease progression or unacceptable toxicity. Treatment response was evaluated with image-based assessment according to response evaluation criteria insolid tumors (RECIST) version 1.1. by two experienced experts and further explored multiple methods, such as 3D visualisation and Spectral computed tomography Scan. The primary endpoint was the objective response rate (ORR); the secondary endpoints are disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Exploratory endpoints included associations between response, molecular characteristics, and the immune microenvironment. Results: Between June 30, and January 31, 2024, a total of 30 patients have undergone at least one imaging evaluation. 66.7% of these patients were diagnosed with ICC, 23.3% with GBC, and 10% with ECC. The mean age was 58.4 years, and 60% of the patients were male. 24 (80%) patients had metastasis. Among them, 1 (3.3%) patient acheived complete response (CR), 15 (50%) patients had partial response (PR) and 8 (26.7%) patients presented with stable disease (SD). The ORR was 53.3% and the DCR was 80%. The most common treatment-related adverse events (TRAEs) of any grade were rash (80%) and anaemia (76.7%). Grade 3 TRAEs were observed in 66.7% of the patients. The most frequent grade 3 TRAEs were anaemia (33.3%), and leukocytopenia (33.3%). No grade 4 or 5 events were observed. All patients were microsatellite stable (MSS), and the median TMB was 2.88 (0-109.44) Muts/Mb. Conclusions: Cadonilimab plus gemcitabine and cisplatin shown a promising efficacy and acceptable safety profile as first-line treatment for advanced BTC patients. Clinical trial information: NCT05978609 .

Utility of spectral CT with orthopedic metal artifact reduction algorithms for 125I seeds implantation in mediastinal and hepatic tumors.

Virtual monochromatic image (VMI) combined with orthopedic metal artifact reduction algorithms (VMI + O-MAR) can effectively reduce artifacts caused by metal implants of different types. Nevertheless, so far, no study has systematically evaluated the efficacy of VMI + O-MAR in reducing various types of metal artifacts induced by 125I seeds. The aim of this study was to assess the effectiveness of combining spectral computed tomography (CT) images with O-MAR in reducing metal artifacts and improving the image quality affected by artifacts in patients after 125I radioactive seeds implantation (RSI). A total of 45 patients who underwent dual-layer detector spectral CT (DLCT; IQon, Philips Healthcare) scanning of mediastinal and hepatic tumors after 125I RSI were retrospectively included. Spectral data were reconstructed into conventional image (CI), VMI, CI combined with O-MAR (CI + O-MAR), and VMI + O-MAR to evaluate the de-artifact effect and image quality improvement. Objective indicators included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and artifact index (AI) of lesions affected by artifacts. Subjective indicators included assessment of overcorrected artifacts and new artifacts, different morphology of artifacts, and overall image quality. In artifact-affected lesion areas, SNR and CNR in the CI/VMI + O-MAR groups were better than those in CI groups (all P values <0.05). The AI showed a downward trend as VMI keV increased (all P values <0.001). The AI values of the CI/VMI (50-150 keV) group were all higher than the groups of CI/VMI + O-MAR (50-150 keV) (P<0.001). Overcorrection artifacts and new artifacts were concentrated in the VMI50/70 keV groups. In the evaluation of artifact morphology, as the VMI keV increased, the number of near-field banding artifacts in hyperdense artifacts gradually decreased, whereas the number of minimal or no artifacts increased, and the total number of hyperdense artifacts were decreased. The diagnostic and image quality scores of hyperdense artifacts were higher than those of hypodense artifacts as VMI keV increased. High VMI level combined with O-MAR substantially improve objective and subjective image quality, lesion display ability, and diagnostic confidence of CT follow-up after 125I RSI, especially at the VMI + O-MAR 150 keV level.

Preliminary exploration of the correlation between spectral computed tomography quantitative parameters and spread through air spaces in lung adenocarcinoma.

The invasive pattern called spread through air spaces (STAS) is linked to an unfavorable prognosis in patients with lung adenocarcinoma (LUAD). Using computed tomography (CT) signs alone to assess STAS is subjective and lacks quantitative evaluation, whereas spectral CT can provide quantitative analysis of tumors. The aim of this study was to investigate the association between spectral CT quantitative parameters and STAS in LUAD. We retrospectively collected consecutive patients with LUAD who underwent surgical resection and preoperative spectral CT scan at our institution. The quantitative parameters included CT values at 40, 70, and 100 keV [CT40keVa/v, CT70keVa/v, and CT100keVa/v (a: arterial; v: venous)]; iodine concentration (ICa/ICv); normalized iodine concentration (NICa/NICv); and slope λHU of the spectral curve (λHUa/λHUv). Clinical and CT features of the patients were also collected. Statistical analysis was performed to identify the quantitative parameters, clinical and CT features that were significantly correlated with STAS status. We evaluated the diagnostic performance of significant factors or models which combined quantitative parameters and CT features, using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve. We enrolled a total of 47 patients, with 32 positive and 15 negative for STAS. The results revealed that CT100keVa (P=0.002), CT100keVv (P=0.007), pathologic stage (P=0.040), tumor density (P<0.001), spiculation (P=0.003), maximum solid component diameter (P=0.008), and the consolidation/tumor ratio (CTR) (P=0.001) were significantly correlated with STAS status. The tumor density demonstrated a superior diagnostic capability [AUC =0.824, 95% confidence interval (CI): 0.709-0.939, sensitivity =59.4%, specificity =100.0%] compared to other variables. CT100keVa exhibited the best diagnostic performance (AUC =0.779, 95% CI: 0.633-0.925, sensitivity =78.1%, specificity =80.0%) among the quantitative parameters. Combination models were then constructed by combining the quantitative parameters with CT features. The total combined model showed the highest diagnostic efficiency (AUC =0.952, 95% CI: 0.894-1.000, sensitivity =90.6%, specificity =86.7%). Spectral CT quantitative parameters CT100keVa and CT100keVv may be potentially useful parameters in distinguishing the STAS status in LUAD.

Rapid-kilovoltage-switching dual-energy computed tomography (CT) for differentiating spinal osteolytic metastases from spinal infections.

Rapid-kilovoltage-switching dual-energy computed tomography (RDECT) is a non-invasive, alternative technique for quantitative diagnosis. This study aimed to investigate the value of RDECT for differentiating spinal osteolytic metastases (SOM) from spinal infections (SIs). RDECT was performed on 29 patients with SOM and 18 patients with SIs. Both iodine-based and water-based material decomposition images were generated from the spectral CT scan. The iodine/water densities of lesions on iodine/water material-decomposition images and the CT attenuation values on traditional CT images were measured three times at different image levels, and the averages were calculated. The lesion-to-muscle ratio (LMR) and lesion-to-artery ratio (LAR) for iodine density measurements were calculated. All parameters were compared between the two groups using the two-tailed Student's t-test. A P value <0.05 was considered statistically significant. The sensitivity and specificity for differentiating SOM from SIs were determined using receiver operating characteristic curves (ROC). Iodine density, LMR, and LAR during the arterial phase (AP) and venous phase (VP) were all significantly higher for SOM than for SIs (all P<0.05). The water densities and traditional CT attenuation values during the AP and VP were not significantly different between the two groups. For ROC analysis, LAR during the VP (LARVP) showed the best diagnostic performance, with an area under the ROC curve (AUC) value of 0.862. When the LARVP was 0.54, the sensitivity was 82.80% and the specificity was 77.80% for differentiating SOM from SIs. RDECT can provide additional information that may be useful for differentiating atypical SOM from SIs.

Metal artifact reduction using mono-energy images combined with metal artifact reduction software in spectral computed tomography: a study on phantoms.

This study aimed to evaluate the effectiveness of spectral computed tomography (CT) mono-energy imaging combined with metal artifact reduction software (MARs) for metal implant artifact reduction using a phantom. A quantitative standard phantom with 9 cylinders was used to simulate the attenuation of the different tissues of the human body around the metal implant. Groups A and B were divided according to conventional CT scan mode and spectral CT scan mode. Three sets of reconstructed images, including 120 kVp-like + MARs images, mono-energy images (MonoE), and MonoE + MARs images, were generated after spectral CT scanning. High-attenuation artifacts and low-attenuation artifacts were observed around the coil in the images of groups A and B. The CT values (Hounsfield unit) and standard deviation (SD) values of the artifacts were measured, and the artifact index and hardening artifact removal rate were calculated. Compared to conventional poly-energy CT images, for high-attenuation and low-attenuation artifacts, the artifact indices of 120 kVp-like + MARs, MonoE, and MonoE + MARs images were all reduced significantly. The hardening artifact removal rates of the high-attenuation and low-attenuation artifacts of 120 kVp-like + MARs images were 82% and 92%, respectively. The hardening artifact removal rate of the high-attenuation and low-attenuation artifacts of MonoE and MonoE + MARs images increased with the mono-energy level. Spectral CT using the 120 kVp-like + MARs, 110-140 keV MonoE, and MonoE + MARs reconstruction methods can reduce metal implant artifacts in varying degrees. MonoE + MARs reconstruction was the best method for reducing metal artifacts.

Evaluation of the anti-angiogenic effect of bevacizumab on rat C6 glioma by spectral computed tomography.

Anti-angiogenic drugs have become a research hotspot in recent years. However, dynamically observing their therapeutic effect at different time points during treatment is a clinical problem. To explore the feasibility of the quantitative parameters of spectral computed tomography (CT) in evaluating the anti-angiogenic effect of bevacizumab on rat C6 glioma. Twenty-six male Sprague-Dawley rats were used to establish the C6 glioma model. The rats were randomly divided into the experimental group (n = 13) and control group (n = 13). The experimental group was intraperitoneally injected with 0.2 µL/g bevacizumab every day, whereas the control group was injected with the same dose of normal saline every day for one week. Spectral CT scanning was performed on the 4th and 8th days after treatment; meanwhile, the brain tissues were collected by heart perfusion for H&E staining, and VEGF and HIF-1α immunohistochemical staining. On the 4th and 8th days, significant differences in the 70-keV single-energy CT value, slope of the energy spectrum curve, and iodine concentration were found between the experimental group and the control group. Correlation analysis between immunohistochemistry and quantitative parameters of spectral CT showed that the single energy CT value of 70 keV, slope of the energy spectrum curve, and concentration of iodine were positively correlated with VEGF and HIF-1α at different time points in the experimental group and the control group. Spectral CT multi-parameter imaging can be employed as a new method to evaluate the anti-angiogenic effect of bevacizumab on rat C6 glioma.

Comparison of spectral computed tomography imaging parameters between squamous cell carcinoma and adenocarcinoma at the gastroesophageal junction.

To compare the spectral computed tomography (CT) imaging parameters between squamous cell carcinoma (SCC) and adenocarcinoma (AC) at the gastroesophageal junction (GEJ). A total of 80 patients were enrolled in this retrospective study. Among them, 35 were diagnosed with SCC (SCC group) and 45 were diagnosed with AC (AC group). All patients underwent an enhanced scan with spectral CT. The following CT imaging parameters were evaluated: iodine concentration (IC), water content (WC), effective atomic number (Eff-Z) and slope of the spectral HU curve (λHU) of lesions. Receiver operating characteristic (ROC) curve was used to analyze the predictive value of spectral CT imaging parameters for diagnosis of SCC and AC. Patients with SCC had lower IC, Eff-Z, and λHU in arterial phase and venous phase compared with AC (p< 0.05). There were no significant differences in WC between the two groups. ROC curve analyses revealed that IC, Eff-Z, and λHU in arterial phase and venous phase were predictors for diagnosis of SCC and AC (AUC > 0.5). Moreover, the IC, Eff-Z and λHU in venous phase had better differential diagnostic performances than that in arterial phase. Spectral CT could be useful in the differential diagnosis of SCC and AC at the GEJ. Therefore, a routine spectral CT scan is recommended for patients with carcinoma of the GEJ.

Quantification of Fat Concentration and Vascular Response in Brown and White Adipose Tissue of Rats by Spectral CT Imaging.

ObjectiveThe purpose of the study was to non-invasively characterize and discriminate brown adipose tissue (BAT) from white adipose tissue (WAT) in rats using spectral computed tomography (CT) with histological validation.Materials and MethodsA lipid-containing phantom (lipid fractions from 0% to 100%) was imaged with spectral CT. An in vivo, non-enhanced spectral CT scan was performed on 24 rats, and fat concentrations of BAT and WAT were measured. The rats were randomized to receive intraperitoneal treatment with norepinephrine (NE) (n = 12) or saline (n = 12). Non-enhanced and enhanced spectral CT scans were performed after treatment to measure the elevation of iodine in BAT and WAT. The BAT/aorta and WAT/aorta ratios were calculated and compared, after which isolated BAT and WAT samples were subjected to histological and uncoupling protein 1 (UCP1) analyses.ResultsThe ex-vivo phantom study showed excellent linear fit between measured fat concentration and the known gravimetric reference standard (r2 = 0.996). In vivo, BAT had significantly lower fat concentration than WAT (p < 0.001). Compared to the saline group, the iodine concentration of BAT increased significantly (p < 0.001) after injection of NE, while the iodine concentration of WAT only changed slightly. The BAT/aorta ratio also increased significantly after exposure to NE compared to the saline group (p < 0.001). Histological and UCP1 expression analyses supported the spectral CT imaging results.ConclusionThe study consolidates spectral CT as a new approach for non-invasive imaging of BAT and WAT. Quantitative analyses of BAT and WAT by spectral CT revealed different characteristics and pharmacologic activations in the two types of adipose tissue.

Optimized energy thresholds in a spectral computed tomography scan for contrast agent imaging

Spectral computed tomography (CT) based on photon counting detectors (PCDs) is a well-researched topic in the field of X-ray imaging. When PCD is applied in a spectral CT system, the PCD energy thresholds must be carefully selected, especially for K-edge imaging, which is an important spectral CT application. This paper presents a threshold selection method that yields better-quality images in K-edge imaging. The main idea is to optimize the energy thresholds ray-by-ray according to the targeted component coefficients, followed by obtaining an overall optimal energy threshold by frequency voting. A low-dose pre-scan is used in practical implementations to estimate the line integrals of the component coefficients for the basis functions. The variance of the decomposed component coefficients is then minimized using the Cramer–Rao lower bound method with respect to the energy thresholds. The optimal energy thresholds are then used to take a full scan and gain better image reconstruction with less noise than would be given by a full scan using the non-optimal energy thresholds. Simulations and practical experiments on imaging iodine and gadolinium solutions, which are commonly used as contrast agents in medical applications, were used to validate the method. The noise was significantly reduced with the same dose relative to the non-optimal energy thresholds in both simulations and in practical experiments.

Creeping fat in patients with ileo-colonic Crohn's disease correlates with disease activity and severity of inflammation: A preliminary study using energy spectral computed tomography.

To investigate the relationship between creeping fat and inflammatory activity as well as the prognosis of ileo-colonic Crohn's disease (CD), based on a quantitative analysis of energy spectral computed tomography (CT). A total of 40 patients with CD and 40 with other gastrointestinal diseases who underwent an energy spectral CT scanning between March 2014 and March 2015 were retrospectively enrolled. The endoscopic severity of CD was evaluated by the simple endoscopic score for Crohn's disease (SES-CD). The slope of the Hounsfield unit (HU) curve (λHU ) was measured and calculated on energy spectral CT images. Visceral and subcutaneous fat areas were also measured. The relationship between the quantitative data of creeping fat as well as the fat area and CD inflammation were analyzed. The λHU of creeping fat in patients with CD increased with the severity of intestinal inflammation (moderate/severe vs mild: -0.17 ± -0.68 vs -0.49 ± -0.61, P < 0.01). Moreover, the λHU of creeping fat around the intestinal segments without lesions in CD was significantly larger than that in the controls (-1.19 ± -0.56 vs - 1.42 ± -0.45, P < 0.01). The λHU was more accurate for detecting inflammatory lesions in CD than for calculating visceral fat. It was significantly correlated with SES-CD (r = 0.66, P < 0.01) and moderately correlated with the Harvey-Bradshaw index (r = 0.414, P < 0.01). The quantitative analysis of creeping fat using energy spectral CT is an effective method in inflammatory evaluation in patients with CD.

Assessing the Blood Supply Status of the Focal Ground-Glass Opacity in Lungs Using Spectral Computed Tomography.

ObjectiveTo exploit material decomposition analysis in dual-energy spectral computed tomography (CT) to assess the blood supply status of the ground-glass opacity (GGO) in lungs.Materials and MethodsThis retrospective study included 48 patients with lung adenocarcinoma, who underwent a contrast-enhanced dual-energy spectral CT scan before treatment (53 GGOs in total). The iodine concentration (IC) and water content (WC) of the GGO, the contralateral and ipsilateral normal lung tissues were measured in the arterial phase (AP) and their differences were analyzed. IC, normalized IC (NIC), and WC values were compared between the pure ground-glass opacity (pGGO) and the mixed ground-glass opacity (mGGO), and between the group of preinvasive lesions and the minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IA) groups.ResultsThe values of pGGO (IC = 20.9 ± 6.2 mg/mL and WC = 345.1 ± 87.1 mg/mL) and mGGO (IC = 23.8 ± 8.3 mg/mL and WC = 606.8 ± 124.5 mg/mL) in the AP were significantly higher than those of the contralateral normal lung tissues (IC = 15.0 ± 4.9 mg/mL and WC = 156.4 ± 36.8 mg/mL; IC = 16.2 ± 5.7 mg/mL and WC = 169.4 ± 41.0 mg/mL) and ipsilateral normal lung tissues (IC = 15.1 ± 6.2 mg/mL and WC = 156.3 ± 38.8 mg/mL; IC = 15.9 ± 6.0 mg/mL and WC = 174.7 ± 39.2 mg/mL; all p < 0.001). After normalizing the data according to the values of the artery, pGGO (NIC = 0.1 and WC = 345.1 ± 87.1 mg/mL) and mGGO (NIC = 0.2 and WC = 606.8 ± 124.5 mg/mL) were statistically different (p = 0.049 and p < 0.001, respectively), but not for the IC value (p = 0.161). The WC values of the group with preinvasive lesions and MIA (345.4 ± 96.1 mg/mL) and IA (550.1 ± 158.2 mg/mL) were statistically different (p < 0.001).ConclusionUsing dual-energy spectral CT and material decomposition analysis, the IC in GGO can be quantitatively measured which can be an indicator of the blood supply status in the GGO.

Dual-Energy Computed Tomography: Physical Principles, Approaches to Scanning, Usage, and Implementation: Part 1.

There are increasing applications of dual-energy computed tomography (CT), a type of spectral CT, in neuroradiology and head and neck imaging. In this 2-part review, the fundamental principles underlying spectral CT scanning and the major considerations in implementing this type of scanning in clinical practice are reviewed. In the first part of this 2-part review, the physical principles underlying spectral CT scanning are reviewed, followed by an overview of the different approaches for spectral CT scanning, including a discussion of the strengths and challenges encountered with each approach.

Usefulness of spectral computed tomography for evaluation of intestinal activity and severity in ileocolonic Crohn's disease.

Background:Assessment of intestinal activity and severity of Crohn’s disease (CD) is crucial to guide treatment. In this study, we aimed to investigate the accuracy of spectral computed tomography (CT) in this assessment and make a comparison with conventional CT.Methods:A total of 50 patients with ileocolonic CD underwent spectral CT scanning. Conventional CT and spectral CT images were reconstructed. Endoscopic lesions were classified as absent, mild lesions and severe lesions. Qualitative and quantitative findings in CT images were compared in these segments. Logistic regressions were established, based on conventional and spectral CT parameters, to predict intestinal activity and severity. Comparisons were made by receiver operating characteristic (ROC) curve.Results:The results showed that bowel wall hyperenhancement, ulcers on CT images, comb sign, bowel wall thickness, normalized iodine concentration (NIC) and slope of HU curve (λHU) increased significantly (p < 0.01) with endoscopic severity. In predicting intestinal activity, spectral CT demonstrated higher accuracy (99.6% versus 94.7%), sensitivity (99.1% versus 93.4%) and specificity (99.9% versus 94.4%) than conventional CT. In predicting intestinal severity, spectral CT also had higher accuracy (96.5% versus 91.9%), sensitivity (96.5% versus 92.1%) and specificity (95.8% versus 89.8%) than conventional CT. Besides, both NIC and λHU correlated significantly with Simple Endoscopic Score for CD (r = 0.833 and r = 0.771; both p < 0.001), but their correlations with C-reactive protein (r = 0.578 and r = 0.513; both p < 0.01) and Harvey–Bradshaw Index (r = 0.545 and r = 0.522; both p < 0.01) were moderate.Conclusions:Compared with conventional CT, spectral CT had higher accuracy in detecting intestinal activity and severity of CD, which could be an alternative choice in evaluation of CD.

Optimal monochromatic images of abdominal arteries with low concentrations of contrast agents in spectral computed tomography imaging

To explore the application of optimal monochromatic images according to computed tomography (CT) values of conventional CT scans with high concentration contrast agent and the feasibility in guiding abdominal arteries imaging with low concentration contrast. From March 2013 to February 2014, 160 patients of suspected celiac disease with a body mass index (BMI) of >25 kg/m(2) underwent spectral CT scan. And they were randomly divided into two groups. In group A (n = 61), 270 mgI/ml low concentrations of contrast agents and spectral CT imaging; in group B (n = 99), 350 mgI/ml high concentrations of contrast agents and 120 kVp scan. For CT values of the first measurement of abdominal aorta B group of patients, the average CT value was calculated . The optimal monochromatic images of group A according to CT values of group B were reconstructed and 70 keV images (group C) also reconstructed. The CT values of hepatic, splenic, right renal and superior mesenteric arteries were measured and contrast to noise ratios (CNRs) calculated. CT values and CNR were compared through t test on independent samples. P > 0.05 indicated no significant difference. Mean CT value of abdominal aorta was (422 ± 65) HU in group B. And optimal keV was (67 ± 5) keV in group A. CT values of abdominal aorta and its branches showed no statistical significance; the CNRs of abdominal aorta and its branches showed statistical significance. The scoring consistency between two observers was excellent and the score (4.1 ± 0.9 vs 4.2 ± 0.7) showed no significant difference (P > 0.05). GSI abdominal scans with low concentration contrast may obtain better image qualities compared to conventional CTA of high concentration. And (67 ± 5) keV is recommended.