Thiravit Shanigarn, Moleesaide Adisa, Kaewlai Rathachai, Limsakol Chayanit, Maneegarn Arjin, Phothisirisakulwong Arissa, Thiravit Phakphoom
Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Abdom Radiol (NY). 2025 May 2. doi: 10.1007/s00261-025-04964-2.
To assess accuracy of MDI and iodine quantification in distinguishing enhancing renal masses from hyperattenuating cysts, compared with conventional attenuation measurements, given that differentiation between these entities can influence follow-up imaging strategies and surgical decision-making, and to investigate the optimal threshold of iodine concentration using rapid kilovoltage-switching DECT (rsDECT).
Retrospective study enrolled 126 renal lesions 1-4 cm in size with 10-70 attenuation on pre-contrast CT in patients who underwent rsDECT during the portovenous phase. Two reading sessions (true unenhanced (TUE) + post-contrast (PC) + MDI images versus MDI only images) for the visual assessment of renal mass enhancement were done (with at least 1-month time gap). Measurement of attenuation and iodine concentration within each renal lesion was recorded. Diagnostic accuracies and a threshold of each quantitative parameters were evaluated. Final diagnosis of renal lesions was based on pathological or imaging criteria.
Accuracy of MDI images were 90.5% with TUE + PC + MDI and 88.9% with MDI only. AUC of VUE HU, TUE HU, PC HU, PC VUE HU, PC-TUE HU, absolute and normalized iodine concentration were 0.87, 0.82, 0.96, 0.95, 0.96, 0.97 and 0.95 (all p < 0.001). The optimal absolute iodine concentration threshold was 1.6 mg I/mL, with 91% sensitivity and 92% specificity. This threshold outperformed 0.5 mg I/mL showing 100% sensitivity, 29% specificity) and 2.0 mg I/mL showing 71% sensitivity, 97% specificity.
In characterization of a small (< 4 cm) hyperattenuating renal lesion identified on abdominal CT, post processing MDI with iodine quantification has better or comparable accuracy to attenuation measurement and the specificity of iodine concentration using rsDECT improves with a threshold higher than 0.5 mg I/mL. This could enhance diagnostic workflows for renal lesion assessment using MDI and offer the potential to omit TUE scanning, thereby reducing patient radiation exposure.
鉴于区分这些病变实体可能会影响后续成像策略和手术决策，将多能成像（MDI）和碘定量在鉴别强化肾肿块与高密度囊肿方面的准确性与传统衰减测量进行比较，并使用快速千伏切换双能CT（rsDECT）研究碘浓度的最佳阈值。
回顾性研究纳入了126例肾病变患者，病变大小为1 - 4 cm，在门静脉期接受rsDECT检查，其在增强前CT上的衰减值为10 - 70。进行了两次阅片（真平扫（TUE）+增强后（PC）+ MDI图像与仅MDI图像）以对肾肿块强化进行视觉评估（间隔至少1个月）。记录每个肾病变内的衰减和碘浓度测量值。评估每个定量参数的诊断准确性和阈值。肾病变的最终诊断基于病理或影像学标准。
TUE + PC + MDI时MDI图像的准确性为90.5%，仅MDI时为88.9%。平扫HU、TUE HU、PC HU、PC平扫HU、PC - TUE HU、绝对和归一化碘浓度的曲线下面积（AUC）分别为0.87、0.82、0.96、0.95、0.96、0.97和0.95（均p < 0.001）。最佳绝对碘浓度阈值为1.6 mg I/mL，敏感性为91%，特异性为92%。该阈值优于0.5 mg I/mL（敏感性100%，特异性29%）和2.0 mg I/mL（敏感性71%，特异性97%）。
在腹部CT上发现的小（< 4 cm）高密度肾病变的特征性分析中，采用碘定量的后处理MDI与衰减测量具有相当或更好的准确性，且使用rsDECT时碘浓度的特异性在阈值高于0.5 mg I/mL时提高。这可以增强使用MDI评估肾病变的诊断流程，并有可能省略TUE扫描，从而减少患者的辐射暴露。
