Dual-energy Computer Tomography Research Articles

Treatment and diagnostics of gout: Unsolved problems in clinical practice

The possibilities for diagnosing and treating gout have expanded significantly. However, this did not lead to solving the problem of timely diagnosis of gout, nor to improving control over it, nor to reducing mortality in patients with gout. In the article possible reasons of absence of the progress in gout control connected with the lack of usage of contemporary capabilities in diagnosis and mistakes in usage of drugs therapy is discussed. These should include the lack of conversance of medical stuff about sonography high informativity for gout diagnosis, low availability of polarizing microscopy and dual energy computer tomography; causeless ignore of prescribing prophylactic symptomatic therapy, usage of inadequate doses of drugs. Another reason may be the absence of unified concept regarding specific indications of prescribing urate-lowering drugs and choice of specific medicine.

RECENT ADVANCES IN COMPUTED TOMOGRAPHY RADIATION DOSIMETRY

Computer tomography (CT) has proved fundamental in image evaluation throughout the past three decades. By combining rapid scanning with high-quality data sets, multi-detector technology continues to influence practice patterns. This has led to new applications and improved use in conventional applications. However, the increased use of CT has generated significant concern regarding the high radiation doses received by patients during CT scans compared to traditional radiography examinations. Many studies have been undertaken on minimizing patient dose and adhering to the as low as reasonably achievable (ALARA) principle. A total of 40 English articles from PubMed, Science Direct and Google Scholar were systematically summarized in this review paper to introduce the growth of CT scan from single-slice to multi-slice technology from 2000 until December 2020 as well as dual-energy and multi-detector CT technologies. The important role of utilizing CT radiation dosimeters for CT dose measurement is defined included CT dose reduction techniques.

Ultrasonic bone cement removal efficiency in total joint arthroplasty revision: A computer tomographic-based cadaver study.

Polymethylmethacrylate (PMMA) removal during septic total joint arthroplasty revision is associated with a high fracture and perforation risk. Ultrasonic cement removal is considered a bone-preserving technique. Currently, there is still a lack of sound data on efficacy as it is difficult to detect smaller residues with reasonable technical effort. However, incomplete removal is associated with the risk of biofilm coverage of the residue. Therefore, the study aimed to investigate the efficiency of ultrasonic-based PMMA removal in a human cadaver model.The femoral components of a total hip and a total knee prosthesis were implanted in two cadaver femoral canals by 3rd generation cement fixation technique. Implants were then removed. Cement mantle extraction was performed with the OSCAR-3-System ultrasonic system (Orthofix®). Quantitative analysis of cement residues was carried out with dual-energy and microcomputer tomography.With a 20 µm resolution, in vitro microcomputer tomography visualized tiniest PMMA residues. For clinical use, dual-energy computer tomography tissue decomposition with 0.75 mm resolution is suitable. With ultrasound, more than 99% of PMMA was removed. Seven hundred thirty-fourresidues with a mean volume of 0.40 ± 4.95 mm3 were identified with only 4 exceeding 1 cm in length in at least one axis.Ultrasonic cement removal of PMMA was almost complete and can therefore be considered a highly effective technique. For the first time, PMMA residues in the sub-millimetre range were detected by computer tomography. Clinical implications of the small remaining PMMA fraction on the eradication rate of periprosthetic joint infection warrants further investigations.

MP061 - Diagnostic accuracy of Dual Energy Computer Tomography (DECT) in pure and mixed urate stones

MP061 - Diagnostic accuracy of Dual Energy Computer Tomography (DECT) in pure and mixed urate stones

Multi-energy level fusion for nodal metastasis classification of primary lung tumor on dual energy CT using deep learning

Lymph node metastasis also called nodal metastasis (Nmet), is a clinically primary task for physicians. The survival and recurrence of lung cancer are related to the Nmet staging from Tumor-Node-Metastasis (TNM) reports. Furthermore, preoperative Nmet prediction is still a challenge for the patient in managing the surgical plan and making treatment decisions. We proposed a multi-energy level fusion model with a principal feature enhancement (PFE) block incorporating radiologist and computer science knowledge for Nmet prediction. The proposed model is custom-designed by gemstone spectral imaging (GSI) with different energy levels on dual-energy computer tomography (CT) from a primary tumor of lung cancer. In the experiment, we take three different energy level fusion datasets: lower energy level fusion (40, 50, 60, 70 keV), higher energy level fusion (110, 120, 130, 140 keV), and average energy level fusion (40, 70, 100, 140 keV). The proposed model is trained by lower energy level fusion that is 93% accurate and the value of Kappa is 86%. When we used the lower energy level images to train the fusion model, there has been a significant difference to other energy level fusion models. Hence, we apply 5-fold cross-validation, which is used to validate the performance result of the multi-keV model with different fusion datasets of energy level images in the pathology report. The cross-validation result also demonstrates that the model with the lower energy level dataset is more robust and suitable in predicting the Nmet of the primary tumor. The lower energy level shows more information of tumor angiogenesis or heterogeneity provided the proposed fusion model with a PFE block and channel attention blocks to predict Nmet from primary tumors.

Factors associated with bone erosion in patients with gout: A dual-energy gemstone spectral imaging computed tomography study.

This study aimed to assess the factors influencing bone erosion (BE) in patients with gout using dual-energy gemstone spectral imaging computer tomography. We compared the clinical data, laboratory indices, and tissue urate levels at the monosodium urate (MSU) bone interface measured by dual-energy gemstone spectral imaging computed tomography of 87 gout patients with (n = 41) and without (n = 46) BE. Logistic regression analysis was used to investigate the risk factors associated with BE. In total, 47.1% of patients with gout had BE. The disease duration, serum uric acid, tissue urate levels, and the presence of tophi were significantly higher (p < .05) in gout patients with BE than in those without BE. Longer disease duration (odds ratio = 1.11, 95% confidence interval: 1.00-1.24, p < .05) and increased tissue urate levels (odds ratio = 1.01, 95% confidence interval: 1.00-1.02, p < .05) were independently associated with BE. Tissue urate levels at the MSU-bone interface were correlated with the presence of tophi (r = 0.62, p < .001), BE (r = 0.51, p < .001), renal calculus (r = 0.24, p = .03), and serum uric acid levels (r = 0.23, p = .03). This study found that longer disease duration and elevated tissue urate concentrations at the MSU-bone interface were associated with BE in patients with gout.

Comparison of dual-energy computer tomography and dynamic contrast-enhanced MRI for evaluating lung perfusion defects in chronic thromboembolic pulmonary hypertension.

ObjectivesTo evaluate the agreement in detecting pulmonary perfusion defects in patients with chronic thromboembolic pulmonary hypertension using dual-energy CT and dynamic contrast-enhanced MRI. Second, to compare both imaging modalities in monitoring lung perfusion changes in these patients after undergoing pulmonary endarterectomy.Methods20 patients were examined with CT and MRI before and/or after pulmonary endarterectomy. Estimated perfusion defect percentage from both modalities was compared in a lobe-based analysis. Spatial agreement of perfusion defect maps was also assessed.ResultsA significant correlation between CT and MRI based perfusion defect percentage was calculated in all lung lobes (r > 0.78; p < 0.001). In addition, a good spatial agreement between perfusion defect maps was found (mean spatial overlap for the whole lung was 68.2%; SD = 6.9). Both CT and MRI detected improvements in pulmonary perfusion after pulmonary endarterectomy: 8% and 7% decrease in whole lung perfusion defect percentage (p = 0.007 and 0.004), respectively. In a lobe-wise analysis, improvements were statistically significant only in lower lobes using both modalities (reduction in defect percentage ranged from 16–29%; p < 0.02).ConclusionsDual-energy CT is an alternative to MRI in monitoring chronic thromboembolic pulmonary hypertension. Both imaging modalities provided comparable estimations of perfusion defects and could detect similar improvement in lung perfusion after pulmonary endarterectomy.

Dual energy CT image prediction on primary tumor of lung cancer for nodal metastasis using deep learning.

Lymph node metastasis (LNM) identification is the most clinically important tasks related to survival and recurrence from lung cancer. However, the preoperative prediction of nodal metastasis remains a challenge to determine surgical plans and pretreatment decisions in patients with cancers. We proposed a novel deep prediction method with a size-related damper block for nodal metastasis (Nmet) identification from the primary tumor in lung cancer generated by gemstone spectral imaging (GSI) dual-energy computer tomography (CT). The best model is the proposed method trained by the 40 keV dataset achieves an accuracy of 86 % and a Kappa value of 72 % for Nmet prediction. In the experiment, we have 11 different monochromatic images from 40∼140 keV (the interval is 10 keV) for each patient. When we used the model of 40 keV dataset, there has significant difference in other energy levels (unit of keV). Therefore, we apply in 5-fold cross-validation to explain the lower keV is more efficient to predict Nmet of the primary tumor. The result shows that tumor heterogeneity and size contributed to the proposed model to estimate whether absence or presence of nodal metastasis from the primary tumor.

Determination of the test-samples electron density via dual energy computer tomography

In this work we determines electron density using data obtained via CT scanner with one radiation source operating in two modes: with 80 kV and 120 kV voltage. We perform tomography study of calibration phantom with predetermined electron densities. Single linear relationship between energy-subtracted Hounsfield unit and relative electron density is determined. Using determined relationship the relative electron densities of phantom calibration samples is calculated. The comparison of calculated and nominal values proves the possibility of the samples relative electron density determination using energy-subtracted Hounsfield unit with error less than 2%.

A method for material decomposition and quantification with grating based phase CT.

Material decomposition (MD) is an important application of computer tomography (CT). For phase contrast imaging, conventional MD methods are categorized into two types with respect to different operation sequences, i.e., “before” or “after” image reconstruction. Both categories come down to two-step methods, which have the problem of noise amplification. In this study, we incorporate both phase and absorption (PA) information into MD process, and correspondingly develop a simultaneous algebraic reconstruction technique (SART). The proposed method is referred to as phase & absorption material decomposition-SART (PAMD-SART). By iteratively solving an optimization problem, material composition and substance quantification are reconstructed directly from absorption and differential phase projections. Comparing with two-step MD, the proposed one-step method is superior in noise suppression and accurate decomposition. Numerical simulations and synchrotron radiation based experiments show that PAMD-SART outperforms the classical MD method (image-based and dual-energy CT iterative method), especially for the quantitative accuracy of material equivalent atomic number.

Clinical value of energy spectrum curves of dual-energy computer tomography may help to predict pathological grading of gastric adenocarcinoma.

BackgroundTo explore the clinical value of energy spectrum curves of dual-energy computer tomography (CT) in quantitative evaluation of different pathological grades of gastric adenocarcinoma.MethodsA total of 62 patients with 36 poorly, 25 moderately and 1 well differentiated gastric adenocarcinomas confirmed pathologically were collected. Dual-energy CT plain and enhanced scanning were undergone before operation. Dual-Energy software was used to measure the slope of the energy spectrum curves (λ) in arterial and venous phases (VPs) after image reconstruction. Patients were divided into two groups according to the pathological results, including well and moderately differentiated gastric adenocarcinoma group and poorly differentiated gastric adenocarcinoma group. Data of each group were analyzed by independent sample t-test. Receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficiency of the corresponding parameters.ResultsThere were significant differences in λ values of 40–50, 40–60, 40–80, 40–90, 40–100, 40–120, 40–130, 40–140 and 40–150 keV energy ranges in VP between the well and moderately differentiated group and poorly differentiated group (P<0.05), but no significant differences in λ values of different energy ranges in arterial phase (AP) between the two groups (P>0.05). And the area under curve in 40–120 keV energy range was the largest in VP. λ40–120keV=2.69 was selected as the diagnostic threshold with the maximum Youden index, the sensitivity and specificity were 61.1% and 76%, respectively.ConclusionsThe energy spectrum curve of dual-energy CT had certain diagnostic value in the quantitative evaluation of pathological grading of gastric adenocarcinoma.

Foot and Ankle Characteristics in Gout: A Systematic Review

Objectives: Gout has a predilection for the foot and ankle, but the impact of gout has limited presence in the literature. The aim of this systematic review was to synthesise existing literature which has investigated the characteristics of foot and ankle involvement in gout; identifying consensus and highlighting areas for further study. Methods: Studies were included if they were published in English and involved participants over 18 years of age with gout, and presented original findings relating to outcome measures associated with the foot and ankle. Methodological quality was assessed using a modified version of the Quality Index Tool. Results. Of 707 studies identified, 16 met the inclusion criteria and were included in this review. The mean (range) quality score was 68.1% (38.9%-88.9%). Compared to controls, participants with gout reported higher levels of activity limitation, foot-related pain and disability and walked more slowly. Plain radiography, dual-energy Computer Tomography and diagnostic ultrasound consistently demonstrated pathological features of gout in the first metatarsophalangeal joint and Achilles tendon. However, studies offered limited quality, particularly around recruitment strategies, validity and potential impact of confounding factors, making definitive statements difficult. Conclusions: This systematic review highlights the negative impact of gout on the structure and function of the foot and ankle causing significant impairment and disability. To effectively guide management, improvements in methodological quality are recommended.

Effect of Overeating Dietary Protein at Different Levels on Circulating Lipids and Liver Lipid: The PROOF Study.

Background: During overeating, a low protein diet slowed the rate of weight gain and increased the energy cost of the added weight, suggesting that low protein diets reduced energy efficiency. The Protein Overfeeding (PROOF) study explored the metabolic changes to low and high protein diets, and this sub-study examined the changes in body composition and blood lipids when eating high and low protein diets during overeating. Methods: Twenty-three healthy volunteers (M = 14; F = 9) participated in an 8-week, parallel arm study where they were overfed by ~40% with diets containing 5% (LPD = low protein diet), 15% (NPD = normal protein diet), or 25% (HPD = high protein diet) protein. Dual energy X-ray absorptiometry (DXA) and computer tomography (CT) were used to quantify whole body and abdominal fat and intrahepatic lipid, respectively. Metabolites were measured by standard methods. Results: Protein intake and fat intake were inversely related since carbohydrate intake was fixed. Although overeating the LPD diet was associated with a significant increase in high density lipoprotein (HDL)-cholesterol (p < 0.001) and free fatty acids (p = 0.034), and a significant decrease in fat free mass (p < 0.0001) and liver density (p = 0.038), statistical models showed that dietary protein was the main contributor to changes in fat free mass (p = 0.0040), whereas dietary fat was the major predictor of changes in HDL-cholesterol (p = 0.014), free fatty acids (p = 0.0016), and liver fat (p = 0.0007). Conclusions: During 8 weeks of overeating, the level of dietary protein intake was positively related to the change in fat free mass, but not to the change in HDL-cholesterol, free fatty acids, and liver fat which were, in contrast, related to the intake of dietary fat.

An Unusual Presentation of Gout Involving the Ankle Ligaments

Gout is the most common inflammatory arthritis due to deposition of monosodium urate (MSU) crystals in joints and connective tissues. In contrast to joint disease, the majority of extra-articular involvement remains asymptomatic in patients with gout. Achilles tendon is the most common site of involvement and the inflammation elicited by MSU crystals can be falsely attributed to injury or overuse. In addition, tendon or ligament damage secondary to MSU crystal deposition can lead to ligament tear or tendon rupture.However, the diagnosis of gout in patients with extra-articular involvement is often delayed or even missed because tissue sampling is not feasible in routine clinical practice. Advanced imaging techniques using ultrasound and dual-energy computer tomography (DECT) can detect MSU crystal deposition in a non-invasive manner and confirm the diagnosis of gout in patients with extra-articular involvement.The following case demonstrates an atypical presentation of gout causing multiple ligament tears in the ankle and highlights the role of DECT in the diagnosis of gout with extra-articular involvement.

Current and Future Applications of Thoracic Dual-Energy CT in Children: Pearls and Pitfalls of Technique and Interpretation

Dual-energy computer tomography (DECT) technology has experienced rapid growth in recent years, now allowing for the collection of 2 CT data sets and opening the potential for functional data acquisition. Data from a single postcontrast phase are deconstructed and Iodine can be subtracted to create a virtual noncontrast image, or selectively represented as a contrast map that allows for the qualification and quantification of lung perfusion. Virtual monoenergetic images can also be used to reduce beam-hardening artifact from concentrated contrast or metal implants. In children, DECT is of particular interest because it has been shown to be dose neutral in most applications, dose-reducing in multiphase studies, and to increase the contrast to noise ratio in suboptimal studies. We review the basics of acquisition, postprocessing, and thoracic applications of DECT with a focus on pulmonary blood volumes as a surrogate for perfusion imaging. The discussed applications include pulmonary embolism, hypoplastic lung, pulmonary hypertension in bronchopulmonary dysplasia, and pediatric lung masses.

CONTROVERSIES AND CHALLENGES IN DEFINING SARCOPENIC OBESITY

Sarcopenia is defined as the loss of muscle mass, strength and physical function with aging and in conjunction with obesity, leads to incrementally adverse outcomes. There is no current consensus for defining this disease entity, making an accurate evaluation challenging in both the research and clinical settings. We will review the definitions put forth by the Sarcopenia Definition and Outcomes Consortium and the European Working Group for the Study of Sarcopenia. We will present data highlighting the different diagnostic criteria of sarcopenic obesity and the diagnostic accuracy of common anthropometric measures in measuring adiposity using data from the National Health and Nutrition Examination surveys. The advantages and disadvantages of the different modalities of assessing body composition will be discussed, including body impedance analysis, dual energy x-ray absorptiometry, computer tomography and magnetic resonance imaging in addition to simple, novel clinical screening tools for obesity sarcopenia will be presented.

Diagnostic accuracy of dual-energy CT for detection of bone marrow lesions in the subacutely injured knee with MRI as reference method.

Dual-energy computer tomography (DECT) can detect post-traumatic bone marrow lesions. Prospective studies of the knee with large numbers of participants and intra-observer agreement assessment are limited. To investigate the diagnostic accuracy of DECT in detecting bone marrow lesions as well as estimating the bone marrow lesion volume in patients with suspected anterior cruciate ligament trauma with magnetic resonance imaging (MRI) as reference standard. Forty-eight consecutive patients with suspected anterior cruciate ligament injury were imaged bilaterally with DECT within a mean of 25 days (range 4-55 days) following injury and MRI within seven days of DECT. Two readers analyzed DECT virtual non-calcium-blinded images. Consensus MRI was reference standard. Intra- and inter-observer agreement were determined using weighted kappa statistics. Sensitivity, specificity, and negative and positive predictive values were calculated. Bone marrow lesion volumes were measured; for comparison, intra-class correlation coefficient was used. The 48 patients (26 men, 22 women; mean age 23 years, age range 15-37 years) were imaged bilaterally yielding 52 knees with bone marrow lesions, of which 44 were in the femur and 41 were in the tibia. Intra- and inter-observer agreement to detect bone marrow lesions was moderate and fair to moderate (κ 0.54-0.66, 95% confidence interval [CI] 0.39-0.80 and 0.37-0.41, 95% CI 0.20-0.57) and overall sensitivity and specificity were 70.1% and 69.1%, respectively. Positive and negative predictive values were 72.9% and 66.1%, respectively. Bone marrow lesion volumes showed excellent intra- and inter-observer agreement (0.83-0.91, 95% CI 0.74-0.94 and 0.76-0.78, 95% CI 0.57-0.87). The diagnostic performance of DECT to detect bone marrow lesions in the subacutely injured knee was moderate with intra- and inter-observer agreement ranging from moderate to substantial and fair to moderate. Bone marrow lesion volume correlation was excellent.

I140 Dual-energy computer tomography (DECT): an emerging technique for the diagnosis of gout

I140 Dual-energy computer tomography (DECT): an emerging technique for the diagnosis of gout

Nitroglycerine use in transcatheter arterial (chemo) embolization in patients with hepatocellular carcinoma: Five-year retrospective study

Addition of nitroglycerine (NTG) to transcatheter arterial embolization/transarterial chemoembolization (TAE/TACE) has been shown to increase deposition of Lipiodol emulsion in hepatocellular carcinoma (HCC) tumors. The aim of this retrospective study was to evaluate if the addition of nitroglycerin (NTG) to TAE/TACE improved treatment response in HCC. Patients with HCC either received (n=42) or did not receive (non-NTG) (n=111) NTG and an emulsion of Lipiodol with or without doxorubicin, followed by embolization with Gelfoam pledgets. Treatment response was monitored using dual-energy computer tomography (CT). Disease progression and overall survival (OS) were monitored. The rate of disease progression in the NTG group was 86.5% and in the non-NTG group was 88.6%. Median time to disease progression was 12 months (95% CI; 9.0, 15.0) for the NTG group and 12 months (95% CI; 10.4, 13.6) for the non-NTG groups (P=0.040). No difference was observed in OS between the NTG (60 months) and the non-NTG groups (41 months) (P=0.117). Multivariate analysis found that in the NTG group, OS was associated with Cancer of the Liver Italian Program (CLIP) stage I and Barcelona Clinic Liver Cancer (BCLC) stage B. Addition of NTG to TAE/TACE did not result in improved OS or disease progression.

Urolithiasis is prevalent and associated with reduced bone mineral density in β-thalassaemia major.

Asymptomatic urolithiasis is common and of mixed composition in patients with β-thalassaemia major. Twenty-seven subjects were imaged using dual-energy computer tomography to determine the presence and composition of urolithiasis. The prevalence of urolithiasis was 59% and affected patients generally had multiple stones, often with more than one component: struvite (33%), calcium oxalate (31%) and cystine (22%). Hypercalciuria was present in 78% of subjects and calcium-containing urolithiasis was associated with reduced femoral neck Z scores.