Dual-kilovolt technique was realized in dual energy X-ray imaging system with computer controlled KV adjustment, filter switching and image acquirement. The dual energy images can be obtained in 2-3 seconds to avoid moving artifact. Low energy photons in high energy X-ray beam can be attenuated effectively by a 2 mm Cu filter to separate the spectra of the high and low energy X-rays. A simplified dual energy decomposition method was used to obtain the soft tissue image. An example of chest dual energy radiographs is presented to illustrate the performance of the system.
Humans ; Radiography, Dual-Energy Scanned Projection ; methods ; Radiography, Thoracic ; Signal Processing, Computer-Assisted

PURPOSE: To evaluate the utility of dual-exposure dual-energy radiography against the standard chest radiography in the discrimination of lung nodules and the presence of nodule calcification. MATERIALS AND METHODS: Twenty-nine patients with a total of 43 peripheral lung nodules were examined by dual-exposure dual-energy radiography (DER) and confirmed by a chest CT were included in the study. Of the identified peripheral lung nodules, 24 showed calcification and 19 did not. Further, 28 lesion-free regions from the same patient population were selected as negative controls. Two radiologists evaluated 71 marked locations using both standard chest radiographs (SR) and DER to determine whether the marked locations represented a true nodule, and whether nodule calcification was present. A continuous rating scale of 0-10 was used to represent each observer's confidence level. We calculated the areas under ROC curves (AUC) for SR alone and for DER, and performed a statistical analysis to compare the results. RESULTS: The ability to discriminate nodules was higher for DER than for SR. However, the was not statistically significant (p = 0.202). Inter-observer agreement was moderate regardless of if DER was used. The predictability of nodule calcification was significantly higher for DER compared to SR (p < .001). Moreover, inter-observer agreement was slight with SR alone but moderate with DER. CONCLUSION: DER, in conjunction with SR, has no additional benefit in small lung nodule discrimination but does provide a significant benefit in the characterization of nodule calcification.
Discrimination (Psychology) ; Humans ; Lung ; Lung Diseases ; Radiography, Dual-Energy Scanned Projection ; ROC Curve ; Thorax

Dual-energy computed tomography,with fast image acquisition at two different X-ray energies,enables material-specific and spectral imaging,which offers objective and quantitative parameters for tumor detection,characterization,staging,and treatment monitoring without increasing radiation exposure.This article reviews the applications of dual-energy computed tomography technique and its applications in the evaluation of lung cancer and elucidates its future developments.
Humans ; Lung Neoplasms ; diagnostic imaging ; Radiation Dosage ; Radiography, Dual-Energy Scanned Projection ; Tomography, X-Ray Computed

This paper was aimed to explore the features of single ventricle with dual source computed tomography (DSCT) and the value of the modality in diagnosis of the single ventricle disease. Dual-source computed tomography imaging of 14 cases of single ventricle compared with the results of surgery and cardiac catheter were retrospectively analyzed. Firstly, 14 cases were classified into three types according to Anderson classification method, including 7 cases(50. 0%) left ventricular type, 3 cases(21. 4%) right ventricular type and 4 cases (28. 6%) undecided ventricular type. Secondly, in accompanying malformation respect, pulmonary stenosis, bilateral superior vena cava, atrial septal defect (ASD) and common atrioventricular valve were presented frequently. Thirdly, affiliated cardiac chamber of left ventricular type were mostly in front of the major cardiac chamber (5 cases,71. 4%), while affiliated cardiac chamber of right ventricular type were behind of the major cardiac chamber totally. Fourthly, more than half of aortas and pulmonary arteries stemming from common cardiac chamber can be seen (8 cases, 57. 1%). Meanwhile the aorta valves were more on the right of pulmonary valve (9 cases, 64. 3%). The classification of 10 cases of single ventricle was compared with the results of surgery, and the coincidence rate is 100%. DSCT can diagnose the single ventricle disease accurately. The aorta, pulmonary artery and coronary artery can be displayed completely and simultaneously as well.
Adolescent ; Child ; Child, Preschool ; Female ; Heart Ventricles ; abnormalities ; diagnostic imaging ; Humans ; Infant ; Male ; Radiography, Dual-Energy Scanned Projection ; methods ; Retrospective Studies ; Tomography, X-Ray Computed ; methods

PURPOSE: To assess the potential of dual-energy computed tomography (DECT) to identify urinary stone components, particularly uric acid and calcium oxalate monohydrate, which are unsuitable for extracorporeal shock wave lithotripsy (ESWL). MATERIALS AND METHODS: This clinical study included 246 patients who underwent removal of urinary stones and an analysis of stone components between November 2009 and August 2013. All patients received preoperative DECT using two energy values (80 kVp and 140 kVp). Hounsfield units (HU) were measured and matched to the stone component. RESULTS: Significant differences in HU values were observed between uric acid and nonuric acid stones at the 80 and 140 kVp energy values (p<0.001). All uric acid stones were red on color-coded DECT images, whereas 96.3% of the nonuric acid stones were blue. Patients with calcium oxalate stones were divided into two groups according to the amount of monohydrate (calcium oxalate monohydrate group: monohydrate> or =90%, calcium oxalate dihydrate group: monohydrate<90%). Significant differences in HU values were detected between the two groups at both energy values (p<0.001). CONCLUSIONS: DECT improved the characterization of urinary stone components and was a useful method for identifying uric acid and calcium oxalate monohydrate stones, which are unsuitable for ESWL.
Adult ; Aged ; Calcium Oxalate/analysis ; Female ; Humans ; Kidney Calculi/*chemistry/*radiography/therapy ; *Lithotripsy ; Male ; Middle Aged ; Patient Selection ; Radiography, Dual-Energy Scanned Projection ; Tomography, X-Ray Computed/*methods ; Ureteral Calculi/*chemistry/*radiography/therapy ; Uric Acid/analysis

The dual energy CT (DECT) technology has been recently employed in the form of two X-ray sources of different energies to enhance the contrast between adjacent structures. Its use in the cardiac arena has been widely highlighted due to the higher temporal resolution. However, it may also be used in the craniocervical and peripheral vasculature for better differentiation between contrast-enhanced vascular lumina and calcified plaques, in the characterisation of ureteric stones, and in the evaluation of hepatic lesions. The objective of this paper is to revisit DECT physics, review the literature and discuss its use in CT neuroangiography with case illustrations from our institution, and impact on dose savings.
Cerebral Angiography ; Constriction, Pathologic ; diagnosis ; Humans ; Image Interpretation, Computer-Assisted ; Intracranial Aneurysm ; diagnosis ; Radiation Dosage ; Radiography, Dual-Energy Scanned Projection ; methods ; Review Literature as Topic ; Tomography, X-Ray Computed ; methods

OBJECTIVETo evaluate the clinical feasibility of dual-source computed tomographic urography using dual-energy virtual non-enhanced CT.

METHODSTotally 240 patients received dual-source CT, which included true non-enhanced CT (TNCT) , nephrographic phase scanning with dual-energy mode (100kVp/230mAs and Sn140kVp/178mAs) , and excretory phase scanning. A contrast bolus injection of 100 ml (370 mgI/ml) contrast agent was applied (4.5ml/s) , followed by 100ml normal saline (4.5ml/s) . Virtual non-enhanced CT (VNCT) image sets were reformatted from 'Liver VNC ' software. The mean CT number, noise, signal to noise ratio (SNR) , image quality, and radiation dose were compared between TNCT and VNCT image sets.

RESULTSThere was no significant difference in mean CT numbers of all organs (P>0.05) . However, VNCT images had significantly lower noise and higher SNR than TNCT images (both P<0.05) . Image quality of VNCT was lower than that of TNCT without significant difference (P>0.05) . Radiation dose of nephrographic phase with dual-energy mode was significantly higher than that of TNCT and excretory phase scanning (P<0.05) .

CONCLUSIONDual-energy VNCT requires less radiation dose and therefore has a potential to replace TNCT in the dual-source CT urography.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Male ; Middle Aged ; Radiation Dosage ; Radiography, Dual-Energy Scanned Projection ; methods ; Reproducibility of Results ; Sensitivity and Specificity ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed ; methods ; Urography ; methods ; Young Adult

BACKGROUNDRecognizing renal vascular variants preoperatively is important in order to avoid vascular complications during surgery. This study aimed to investigate the renal vascular variants with dual-energy computed tomography (DECT) angiography to provide valuable information for surgery.

METHODSA total of 378 patients underwent DECT. The number, size, course and relationships of the renal vessels were retrospectively observed from the scans. Anomalies of renal arteries and veins were recorded and classified. Multiplanar reformations (MPR), maximum intensity projections (MIP), and volume renderings (VR) were used for analysis.

RESULTSIn 378 patients (756 kidneys), renal artery variations were discovered and recorded in 123 kidneys (16.3%, 123/756) of 106 patients (28.0%, 106/378). Type IB (early branches of the only one main renal artery) and IC (accessory renal artery with only one main renal artery) were found most frequently with an incidence of 11.4% (43/378) and 14.5% (55/378). The incidence of renal artery variations in the left kidney was not statistically different than in the right kidney (12.4% vs. 11.1%). The incidence of renal vein variations was detected in 104 patients (27.5%, 104/378). The incidence of venous variants in the right kidney was higher than in the left kidney (20.1% vs. 7.4%), but left renal vein variations were more complex. Variants of the left renal vein were detected in 28 patients including type 1 (circumaortic left renal vein) in eight cases, type 2 (retroaortic left renal vein) in seven cases, type 3 (abnormal reflux) in six cases, type 4 (late venous confluence of left renal vein) in five cases, and type 5 (rare type) in two cases. The frequency of left renal vein variation associated with the left renal accessory artery was significantly higher than with early branches of the left renal artery (P = 0.037).

CONCLUSIONSThe renal vascular variants are rather common and complex. DECT angiography can demonstrate the precise anatomy of the renal vessels, which is a benefit for renal transplantation or other renal operations.

Adult ; Aged ; Aged, 80 and over ; Angiography ; methods ; Female ; Humans ; Kidney ; blood supply ; Male ; Middle Aged ; Radiography, Dual-Energy Scanned Projection ; methods ; Renal Veins ; diagnostic imaging ; Retrospective Studies ; Young Adult

OBJECTIVE: To assess the value of dual-energy subtraction radiography (DESR) in the detection of rib bone lesions. METHODS: The images of DESR and digital radiography (DR) in 66 patients with 118 rib bone lesions were reviewed. The detectability of DESR and DR in the rib bone lesions was analyzed by receiver operating characteristic (ROC) method, and their detection rates were compared in different thoracic regions such as those overlaid with the diaphragm and the mediastinum, located in the region of midaxillary line,and the rest. RESULTS: In the detection of rib bone lesions, the area under ROC curve in the DESR group (Az=0.946) was significantly larger than that in the DR group (Az=0.755). In different regions of the rib lesions, the detection rates of DESR were significantly larger than those of DR (P<0.05). CONCLUSION DESR can improve the detection of rib bone lesions, and is a useful supplement to DR.
Adolescent ; Adult ; Aged ; Bone Neoplasms ; diagnostic imaging ; Female ; Humans ; Male ; Middle Aged ; Radiography, Dual-Energy Scanned Projection ; methods ; Retrospective Studies ; Rib Fractures ; diagnostic imaging ; Ribs ; diagnostic imaging ; Young Adult

To assess the value of noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique on objective and subjective image quality in patients with inflammatory bowel disease (IBD) undergoing abdominal dual-energy computed tomography (DECT).
 Methods: Datasets from 32 patients (22 men, 10 women) with IBD, who underwent abdominal DECT, were reconstructed by using the standard linearly blended (M_0.6), traditional monoenergetic (VMI) and VMI+ algorithms in 10-keV intervals from 40-100 keV. Attenuation in IBD lesions was measured to perform objective evaluation using signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Subjective evaluation was performed by 3 independent blinded radiologists using 5-point Likert scales. The overall image quality, image sharpness, lesion delineation, and image noise were analyzed. 
 Results: Mean SNR and CNR peaked at 40 keV VMI+ series (SNR 8.28±2.34, CNR 5.10±2.10) and they were significantly higher than those in linearly blended (SNR 5.82±1.44, CNR 1.53±0.86) and all VMI series (all P<0.01). Subjective image parameter was the highest for the 50 keV VMI+ series regarding overall image quality (mean 4.80, all P<0.01). The highest image sharpness scores were observed at 40 and 50 keV VMI+ reconstructions (mean 4.14 and 4.25, respectively; P=0.415). VMI+ series at 40 keV provided the highest lesion delineation (mean 4.52, all P<0.01). Image noise was low at the 100 keV VMI+ and VMI series (mean 4.58 and 4.40, respectively; P≥0.11).
 Conclusion: Low-keV VMI+ reconstructions improves SNR, CNR, and subjective image quality significantly in patients with IBD.
Female ; Humans ; Inflammatory Bowel Diseases ; diagnostic imaging ; Male ; Radiographic Image Interpretation, Computer-Assisted ; Radiography, Dual-Energy Scanned Projection ; methods ; Reproducibility of Results ; Retrospective Studies ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed ; methods