From the Radiology Service (M.F., A.A., R.P., L.B.), Urology Service (A.S., L.G.), {Emergency} Service (C.P.), and {Regional Management of Clinical Research and Innovation} (A.M.), Centre Hospitalier Universitaire Gabriel Montpied, 58 Rue Montalembert, 63000 Clermont-Ferrand, France.
Radiology. 2015 Jul;276(1):156-66. doi: 10.1148/radiol.2015141287. Epub 2015 Apr 7.
To evaluate the accuracy of reduced-dose abdominal computed tomographic (CT) imaging by using a new generation model-based iterative reconstruction (MBIR) to diagnose acute renal colic compared with a standard-dose abdominal CT with 50% adaptive statistical iterative reconstruction (ASIR).
This institutional review board-approved prospective study included 118 patients with symptoms of acute renal colic who underwent the following two successive CT examinations: standard-dose ASIR 50% and reduced-dose MBIR. Two radiologists independently reviewed both CT examinations for presence or absence of renal calculi, differential diagnoses, and associated abnormalities. The imaging findings, radiation dose estimates, and image quality of the two CT reconstruction methods were compared. Concordance was evaluated by κ coefficient, and descriptive statistics and t test were used for statistical analysis.
Intraobserver correlation was 100% for the diagnosis of renal calculi (κ = 1). Renal calculus (τ = 98.7%; κ = 0.97) and obstructive upper urinary tract disease (τ = 98.16%; κ = 0.95) were detected, and differential or alternative diagnosis was performed (τ = 98.87% κ = 0.95). MBIR allowed a dose reduction of 84% versus standard-dose ASIR 50% (mean volume CT dose index, 1.7 mGy ± 0.8 [standard deviation] vs 10.9 mGy ± 4.6; mean size-specific dose estimate, 2.2 mGy ± 0.7 vs 13.7 mGy ± 3.9; P < .001) without a conspicuous deterioration in image quality (reduced-dose MBIR vs ASIR 50% mean scores, 3.83 ± 0.49 vs 3.92 ± 0.27, respectively; P = .32) or increase in noise (reduced-dose MBIR vs ASIR 50% mean, respectively, 18.36 HU ± 2.53 vs 17.40 HU ± 3.42). Its main drawback remains the long time required for reconstruction (mean, 40 minutes).
A reduced-dose protocol with MBIR allowed a dose reduction of 84% without increasing noise and without an conspicuous deterioration in image quality in patients suspected of having renal colic.
使用新一代基于模型的迭代重建（MBIR）评估降低剂量腹部 CT 成像对诊断急性肾绞痛的准确性，并与使用 50%自适应统计迭代重建（ASIR）的标准剂量腹部 CT 进行比较。
本研究经机构审查委员会批准，纳入 118 例有急性肾绞痛症状的患者，他们接受了以下两次连续 CT 检查：标准剂量 ASIR 50%和降低剂量 MBIR。两名放射科医生分别独立对两次 CT 检查进行肾结石、鉴别诊断和相关异常的评估。比较两种 CT 重建方法的影像学表现、辐射剂量估计值和图像质量。采用κ 系数评估一致性，采用描述性统计和 t 检验进行统计学分析。
肾结石的诊断观察者内相关性为 100%（κ=1）。肾结石（τ=98.7%；κ=0.97）和梗阻性上尿路疾病（τ=98.16%；κ=0.95）均得到检测，并进行了鉴别或替代诊断（τ=98.87%；κ=0.95）。MBIR 与标准剂量 ASIR 50%相比，可使剂量降低 84%（平均容积 CT 剂量指数，1.7 mGy±0.8[标准差] vs 10.9 mGy±4.6；平均体型特异性剂量估计值，2.2 mGy±0.7 vs 13.7 mGy±3.9；P<.001），而图像质量无明显恶化（降低剂量 MBIR 与 ASIR 50%的平均评分分别为 3.83±0.49 和 3.92±0.27；P=.32）或噪声增加（降低剂量 MBIR 与 ASIR 50%的平均噪声分别为 18.36 HU±2.53 和 17.40 HU±3.42）。其主要缺点仍然是重建时间较长（平均 40 分钟）。
在疑似患有肾绞痛的患者中，MBIR 降低剂量方案可使剂量降低 84%，而不会增加噪声，且不会明显降低图像质量。
