Identification of vanishing tophi by three-dimensional dual-energy computed tomography in a patient with chronic tophaceous gout.
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ABSTRACT:
SUBMITTER: Jung SM
PROVIDER: S-EPMC4706398 | biostudies-other | 2016 Jan
REPOSITORIES: biostudies-other
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Project description:The use of dual-energy computed tomography (DECT) for evaluating urinary calculi has been appreciated due to the modality's capability of differentiating between uric acid (UA) and non-UA stones, which are color coded based on a postprocessing algorithm. No other imaging modality or laboratory test is able to identify the stone composition without first attaining the stone material. Knowledge of the stone composition is clinically significant since UA calculi may be treated medically whereas non-UA calculi may require surgical removal. Regardless of the stone type, ureteral stents are often placed to prevent or treat obstruction. Recent work has demonstrated that commonly used stents are also colored based on their dual energy characteristics and may thereby either improve or obscure the identification of adjacent calculi. Herein, we report the case of a 65-year-old man who underwent percutaneous nephrolithotomy of a large staghorn stone with subsequent significant residual stone fragments noted on a follow-up scan. By using three-dimensional DECT and taking advantage of color contrasting, the stone composition, burden, shape, and boundary were clearly depicted apart from the adjacent stent, resulting in successful medical treatment and obviating the need for further surgical intervention.
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Project description:ImportanceThe prevalence of gout has increased in recent decades. Several clinical studies have demonstrated an association between gout and coronary heart disease, but direct cardiovascular imaging of monosodium urate (MSU) deposits by using dual-energy computed tomography (DECT) has not been reported to date.ObjectiveTo compare coronary calcium score and cardiovascular MSU deposits detected by DECT in patients with gout and controls.Design, setting, and participantsThis prospective Health Insurance Portability and Accountability Act-compliant study included patients with gout and controls who presented to a rheumatologic clinic from January 1, 2017, to November 1, 2018. All consecutive patients underwent DECT to assess coronary calcium score and MSU deposits in aorta and coronary arteries. In addition, cadavers were assessed by DECT for cardiovascular MSU deposits and verified by polarizing microscope. Analysis began in January 2017.Main outcomes and measuresDetection rate of cardiovascular MSU deposits using DECT in patients with gout and control group patients without a previous history of gout or inflammatory rheumatic diseases.ResultsA total of 59 patients with gout (mean [SD] age, 59 [5.7] years; range, 47-89 years), 47 controls (mean [SD] age, 70 [10.4] years; range, 44-86 years), and 6 cadavers (mean [SD] age at death, 76 [17] years; range, 56-95 years) were analyzed. The frequency of cardiovascular MSU deposits was higher among patients with gout (51 [86.4%]) compared with controls (7 [14.9%]) (χ2 = 17.68, P < .001), as well as coronary MSU deposits among patients with gout (19 [32.2%]) vs controls (2 [4.3%]) (χ2 = 8.97, P = .003). Coronary calcium score was significantly higher among patients with gout (900 Agatston units [AU]; 95% CI, 589-1211) compared with controls (263 AU; 95% CI, 76-451; P = .001) and also significantly higher among 58 individuals with cardiovascular MSU deposits (950 AU; 95% CI, 639-1261) compared with 48 individuals without MSU deposits (217 AU; 95% CI, 37-397; P < .001). Among 6 cadavers, 3 showed cardiovascular MSU deposits, which were verified by polarizing light microscope.Conclusion and relevanceDual-energy computed tomography demonstrates cardiovascular MSU deposits, as confirmed by polarized light microscopy. Cardiovascular MSU deposits were detected by DECT significantly more often in patients with gout compared with controls and were associated with higher coronary calcium score. This new modality may be of importance in gout population being at risk from cardiovascular disease.
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Project description:In modern clinical decision-support algorithms, heterogeneity in image characteristics due to variations in imaging systems and protocols hinders the development of reproducible quantitative measures including for feature extraction pipelines. With the help of a reader study, we investigate the ability to provide consistent ground-truth targets by using patient-specific 3D-printed lung phantoms. PixelPrint was developed for 3D-printing lifelike computed tomography (CT) lung phantoms by directly translating clinical images into printer instructions that control density on a voxel-by-voxel basis. Data sets of three COVID-19 patients served as input for 3D-printing lung phantoms. Five radiologists rated patient and phantom images for imaging characteristics and diagnostic confidence in a blinded reader study. Effect sizes of evaluating phantom as opposed to patient images were assessed using linear mixed models. Finally, PixelPrint's production reproducibility was evaluated. Images of patients and phantoms had little variation in the estimated mean (0.03-0.29, using a 1-5 scale). When comparing phantom images to patient images, effect size analysis revealed that the difference was within one-third of the inter- and intrareader variabilities. High correspondence between the four phantoms created using the same patient images was demonstrated by PixelPrint's production repeatability tests, with greater similarity scores between high-dose acquisitions of the phantoms than between clinical-dose acquisitions of a single phantom. We demonstrated PixelPrint's ability to produce lifelike CT lung phantoms reliably. These phantoms have the potential to provide ground-truth targets for validating the generalizability of inference-based decision-support algorithms between different health centers and imaging protocols and for optimizing examination protocols with realistic patient-based phantoms. Classification: CT lung phantoms, reader study.
| S-EPMC9992761 | biostudies-literature
Project description:BackgroundUltrasonography (US) and dual-energy computed tomography (DECT) can assess urate burden in gout. The objective of this study was to compare the quantification of urate deposition provided by US to the one provided by DECT.MethodsPatients with a diagnosis of gout were prospectively recruited to undergo quantification of urate deposition using US and DECT. US examination for tophi and the double contour (DC) sign was performed on the knees and feet and corresponding DECT scans provided volumes of tophi and of overall urate deposition. The primary endpoint was the intra-class correlation coefficient (ICC) of the volume of the index tophus measured by US and DECT and its 95% confidence interval (CI 95%).ResultsOf the 64 patients included, 34 presented with at least one tophus on US. DECT inter-reader agreement for urate deposition was perfect with an ICC of 1 (1-1) and good for the measurement of the index tophus with an ICC of 0.69 (0.47-0.83). The ICC for the measurement of the index tophus between the two techniques was poor with a value of 0.45 (0.1-0.71). The average ratio between the index tophi volume as assessed by DECT and US was 0.65. The number of DC-positive joints did not correlate with DECT volume of overall deposits (Spearman correlation coefficient of 0.23).ConclusionsDECT measurements of tophi give smaller volumes to the same tophi measured with US, and US signs of urate deposition in joints do not correlate with overall DECT volumes of extra-articular deposition.
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Project description:ObjectivesTo analyse the diagnostic impact of dual energy computed tomography (DECT) in acute gout flares and acute calcium pyrophosphate (CPP) crystal arthritis when compared to the gold standard of arthrocentesis with compensated polarised light microscopy. Microscopy results were also compared to musculoskeletal ultrasound (MUS), conventional radiographs, and the suspected clinical diagnosis (SCD).MethodsThirty-six patients with a suspected gout flare (n = 24) or acute CPP crystal arthritis (n = 11, n = 1 suffered from neither) who received a DECT and underwent arthrocentesis were included. Two independent readers assessed DECT images for signs of monosodium urate crystals or calcium pyrophosphate deposition.ResultsSensitivity of DECT for gout was 63% (95% CI 0.41-0.81) with a specificity of 92% (0.41-0.81) while sensitivity and specificity for acute CPP arthritis were 55% (0.23-0.83) and 92% (0.74-0.99), respectively. MUS had the highest sensitivity of all imaging modalities with 92% (0.73-0.99) and a specificity of 83% (0.52-0.98) for gout, while sensitivity and specificity for acute CPP crystal arthritis were 91% (0.59-1.00) and 92% (0.74-0.99), respectively.ConclusionDECT is an adequate non-invasive diagnostic tool for acute gout flares but might have a lower sensitivity than described by previous studies. Both MUS and SCD had higher sensitivities than DECT for acute gout flares and acute CPP crystal arthritis.
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Project description:PurposeVirtual monoenergetic images (VMIs) derived from dual-energy computed tomography (DECT) have been explored for several clinical applications in recent years. However, VMIs at low and high keVs have high levels of noise. The aim of this study was to reduce image noise in VMIs by using a two-step noise reduction technique.MethodsVMI was first denoised using a modified highly constrained backprojection (HYPR) method. After the first-step denoising, a general-threshold filtering method was performed. Two sets of anthropomorphic phantoms were scanned with a clinical dual-source DECT system. DECT data (80/140Sn kV) were reconstructed as VMI series at 12 different energy levels (range, 40-150 keV, interval, 10 keV). For comparison, the averaged VMIs obtained from 10 repeated DECT scans were used as the reference standard. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and root-mean-square error (RMSE) were used to evaluate the quality of VMIs.ResultsCompared to the original HYPR method, the proposed two-step image denoising method could provide better performance in terms of SNR, CNR, and RMSE. In addition, the proposed method could achieve effective noise reduction while preserving edges and small structures, especially for low-keV VMIs.ConclusionThe proposed two-step image denoising method is a feasible method for reducing noise in VMIs obtained from a clinical DECT scanner. The proposed method can also reduce edge blurring and the loss of intensity in small lesions.
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Project description:In the mouse ovary, folliculogenesis proceeds through eight main growth stages, from small primordial type 1 (T1) to fully grown antral T8 follicles. Most of our understanding of this process was obtained with approaches that disrupted the ovary three-dimensional (3D) integrity. Micro-Computed Tomography (microCT) allows the maintenance of the organ structure and a true in-silico 3D reconstruction, with cubic voxels and isotropic resolution, giving a precise spatial mapping of its functional units. Here, we developed a robust method that, by combining an optimized contrast procedure with microCT imaging of the tiny adult mouse ovary, allowed 3D mapping and counting of follicles, from pre-antral secondary T4 (53.2 ± 12.7 μm in diameter) to antral T8 (321.0 ± 21.3 μm) and corpora lutea, together with the major vasculature branches. Primordial and primary follicles (T1-T3) could not be observed. Our procedure highlighted, with unprecedent details, the main functional compartments of the growing follicle: granulosa, antrum, cumulus cells, zona pellucida, and oocyte with its nucleus. The results describe a homogeneous distribution of all follicle types between the ovary dorsal and ventral regions. Also, they show that each of the eight sectors, virtually segmented along the dorsal-ventral axis, houses an equal number of each follicle type. Altogether, these data suggest that follicle recruitment is homogeneously distributed all-over the ovarian surface. This topographic reconstruction builds sound bases for modeling follicles position and, prospectively, could contribute to our understanding of folliculogenesis dynamics, not only under normal conditions, but, importantly, during aging, in the presence of pathologies or after hormones or drugs administration.
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Project description:BackgroundPredicting the risk of flares in patients with gout is a challenge and the link between urate burden and the risk of gout flare is unclear. The objective of this study was to determine if the extent of monosodium urate (MSU) burden measured with dual-energy computed tomography (DECT) and ultrasonography (US) is predictive of the risk of gout flares.MethodsThis prospective observational study recruited patients with gout to undergo MSU burden assessment with DECT (volume of deposits) and US (double contour sign) scans of the knees and feet. Patients attended follow-up visits at 3, 6 and 12 months. Patients having presented with at least one flare at 6 months were compared to those who did not flare. Odds ratios (ORs) (95% confidence interval) for the risk of flare were calculated.ResultsOverall, 64/78 patients included attended at least one follow-up visit. In bivariate analysis, the number of joints with the double contour sign was not associated with the risk of flare (p?=?0.67). Multivariate analysis retained a unique variable: DECT MSU volume of the feet. For each 1 cm3 increase in DECT MSU volume in foot deposits, the risk of flare increased 2.03-fold during the first 6 months after initial assessment (OR 2.03 (1.15-4.38)). The threshold volume best discriminating patients with and without flare was 0.81 cm3 (specificity 61%, sensitivity 77%).ConclusionsThis is the first study showing that the extent of MSU burden measured with DECT but not US is predictive of the risk of flares.
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Project description: Not available
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