From the *Department of Diagnostic and Interventional Radiology, and †Department of Urology, Eberhard Karls University Tübingen, University Hospital Tübingen, Tübingen; and ‡Siemens Healthcare GmbH, Erlangen, Germany.
Invest Radiol. 2016 May;51(5):290-6. doi: 10.1097/RLI.0000000000000234.
The aim of this study was to assess the effect of temporal resolution on semiquantitative and pharmacokinetic parameters from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and their diagnostic accuracy regarding the detection of potentially malignant prostate lesions.
Sixty consecutive male patients (age, 64.5 ± 7.0 years) with clinically suspected prostate cancer were included. All patients underwent multiparametric MRI of the prostate (T2-weighted, diffusion-weighted imaging, and DCE-MRI) on a 3 T MRI scanner. Patients were divided into 2 groups depending on Prostate Imaging Reporting and Data System (PI-RADS) score of the detected lesions (group A: PI-RADS score ≤3, n = 30; group B: PI-RADS score >3, n = 30). In all patients, DCE-MRI was performed using a CAIPIRINHA-Dixon-TWIST Volume-Interpolated Breath-Hold Examination sequence (spatial resolution, 3 × 1.2 × 1.2 mm; temporal resolution, 5 seconds; total sampling duration, 4:10 minutes [250 seconds]) with body weight-adapted administration of contrast agent (gadobutrol, Gadovist; Bayer Healthcare, Berlin, Germany). Six DCE-MRI series with different temporal resolutions ranging from 5 to 30 seconds per time point were retrospectively generated from the original data sets. Semiquantitative parameters (ie, wash-in, wash-out, and time-to-peak [TTP]) as well as pharmacokinetic parameters (ie, Ktrans, Kep, and ve) were calculated for the different temporal resolutions. Both lesion groups and all 6 DCE-MRI series were compared regarding semiquantitative and pharmacokinetic parameters. Diagnostic accuracy for the detection of potentially malignant lesions was calculated for all 6 series using ROC analysis.
A significant effect of temporal resolution was found on wash-in (P < 0.001). Series with temporal resolution lower than 10 s/time point showed significantly lower wash-in values with more pronounced effects in group B compared with group A. For 30-second series, the differences between both groups diminished reaching insignificant levels (P = 0.052), resulting in a significant decrease of the diagnostic accuracy of wash-in (area under the curve, 0.609; 95% confidence interval, 0.451-0.766; P < 0.015). No significant effects were detected on wash-out. For TTP, a significant effect of temporal resolution was detected (P < 0.001) with significantly increasing TTP levels for all down-sampled series compared with the original 5-second series. These effects did not impact the diagnostic accuracy of TTP. No significant effects of temporal resolution were detected on pharmacokinetic parameters (P < 0.112).
In DCE-MRI of the prostate, temporal resolution affects the diagnostic performance of semiquantitative parameters. For a sufficient detection of malignant prostate lesions on DCE-MRI, a temporal resolution of at least 10 s/time point or higher is recommended.
本研究旨在评估时间分辨率对动态对比增强（DCE）磁共振成像（MRI）半定量和药代动力学参数的影响，以及其在检测潜在恶性前列腺病变方面的诊断准确性。
连续纳入 60 例经临床疑似患有前列腺癌的男性患者（年龄 64.5±7.0 岁）。所有患者均在 3T MRI 扫描仪上接受前列腺多参数 MRI（T2 加权、扩散加权成像和 DCE-MRI）检查。根据检测到的病变的前列腺影像报告和数据系统（PI-RADS）评分，将患者分为 2 组（A 组：PI-RADS 评分≤3，n=30；B 组：PI-RADS 评分>3，n=30）。在所有患者中，使用 CAIPIRINHA-Dixon-TWIST Volume-Interpolated Breath-Hold Examination 序列（空间分辨率 3×1.2×1.2mm；时间分辨率 5 秒；总采样持续时间 4:10 分钟[250 秒]）进行 DCE-MRI 检查，根据体重调整对比剂（钆布醇，Gadovist；拜耳医疗保健公司，柏林，德国）的给药剂量。从原始数据集回顾性生成了 6 个时间分辨率不同的 DCE-MRI 系列，每个系列的时间分辨率从 5 秒到 30 秒不等。为不同的时间分辨率计算半定量参数（即洗入、洗出和达峰时间[TTP]）和药代动力学参数（即 Ktrans、Kep 和 ve）。比较了两组病变和所有 6 个 DCE-MRI 系列的半定量和药代动力学参数。使用 ROC 分析计算所有 6 个系列检测潜在恶性病变的诊断准确性。
时间分辨率对洗入有显著影响（P<0.001）。时间分辨率低于 10 秒/时间点的系列显示出明显较低的洗入值，在 B 组中比 A 组更为明显。对于 30 秒的系列，两组之间的差异减小，达到无显著差异水平（P=0.052），导致洗入的诊断准确性显著下降（曲线下面积，0.609；95%置信区间，0.451-0.766；P<0.015）。对洗出无显著影响。对于 TTP，时间分辨率有显著影响（P<0.001），与原始 5 秒系列相比，所有下采样系列的 TTP 水平均显著升高。这些影响并未影响 TTP 的诊断准确性。时间分辨率对药代动力学参数无显著影响（P<0.112）。
在前列腺的 DCE-MRI 中，时间分辨率会影响半定量参数的诊断性能。为了在 DCE-MRI 上充分检测恶性前列腺病变，建议使用至少 10 秒/时间点或更高的时间分辨率。
