Department of Radiology (CCM), Charité - Universitätsmedizin Berlin, Campus Mitte, Humboldt-Universität zu Berlin, Freie Universität Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Canon Medical Systems Europe BV, Zoetermeer, Netherlands.
Eur Radiol. 2020 Jan;30(1):404-412. doi: 10.1007/s00330-019-06350-1. Epub 2019 Jul 22.
To develop a method that allows approximating the mass of monosodium uric acid (MSU) in a gouty tophus using phantom measurements and including tophus density into the calculation of the dual-energy computed tomography (DECT) tophus volumetry.
We prepared specimens of different concentrations of MSU placed in an epoxy-based phantom and an excised porcine foreleg. Density and volumetric measurements were performed in sequential single-source DECT scans acquired with increasingly higher tube currents. We developed a method for estimating the tophus mass by multiplying the detected tophus volume with its mean density and adding a specific gravimetric coefficient k. k was derived from the DECT scans by comparing the approximated MSU masses in the epoxy phantom with the known true MSU masses of the specimens.
Comparison of the approximated MSU masses in the porcine foreleg scans with the true MSU masses of the syringe contents showed similar performance to sole volume measurement while providing additional information on the true uric acid burden: Over 70% of the true urate masses have been detected in MSU concentrations ≥ 45%, while the detection rate was much lower for MSU concentrations ≤ 40%. Retrospective analysis of patients with proven gouty arthritis confirmed the diagnostic potential of the mass approximation technique.
We successfully established a method to include tophus density measurement for estimation of the uric acid burden in milligrams (instead of ml) in a phantom setting for MSU concentrations above 40%. Future studies should validate its use for follow-up in clinical practice.
• Including tophus density measurement in dual-energy computed tomography scans in a phantom setting can be used for estimating the urate burden in milligrams, which might be useful for imaging follow-up. • The mass [mg] of the uric acid burden in a patient with gouty arthritis can be calculated by multiplying volume [ml] with mean density [HU] using a specific gravimetric coefficient. • Retrospective analysis of two patients with gouty tophi showed the relevance of measuring urate mass in addition to urate volume alone.
开发一种方法，使用体模测量来估算痛风石中单钠尿酸盐（MSU）的质量，并将痛风石密度纳入双能 CT（DECT）痛风石容积测量的计算中。
我们制备了不同浓度的 MSU 标本，分别置于环氧树脂体模和一只切除的猪前肢中。在逐步增加管电流的情况下，对标本进行连续的单源 DECT 扫描，进行密度和容积测量。我们开发了一种方法，通过将检测到的痛风石体积乘以其平均密度，并添加特定比重系数 k，来估算痛风石的质量。k 通过比较环氧树脂体模中近似 MSU 质量与标本中已知的真实 MSU 质量，从 DECT 扫描中得出。
与注射器内容物的真实 MSU 质量相比，猪前肢扫描中近似 MSU 质量的比较显示，该方法与单纯体积测量具有相似的性能，同时提供了关于真实尿酸负担的更多信息：在 MSU 浓度≥45%的情况下，超过 70%的真实尿酸盐质量已被检测到，而在 MSU 浓度≤40%的情况下，检测率要低得多。对已确诊的痛风性关节炎患者的回顾性分析证实了该质量估算技术的诊断潜力。
我们成功地建立了一种方法，可在 MSU 浓度高于 40%的体模环境中，通过测量痛风石密度，对毫克（而非毫升）的尿酸负担进行估算。未来的研究应验证其在临床实践随访中的应用。
在体模设置中，包括 DECT 扫描中的痛风石密度测量可用于估算毫克级的尿酸盐负担，这可能对成像随访有用。
痛风性关节炎患者的尿酸盐负担质量（mg）可以通过将体积（ml）乘以平均密度（HU）并使用特定比重系数来计算。
对两名痛风石患者的回顾性分析表明，除了单独测量尿酸盐体积外，测量尿酸盐质量也具有相关性。
