Centre for Biomedical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Department of Radio-Diagnosis, All India Institute of Medical Sciences, New Delhi, India.
MAGMA. 2022 Aug;35(4):609-620. doi: 10.1007/s10334-021-00932-1. Epub 2021 May 29.
To implement an advanced spatial penalty-based reconstruction to constrain the intravoxel incoherent motion (IVIM)-diffusion kurtosis imaging (DKI) model and investigate whether it provides a suitable alternative at 1.5 T to the traditional IVIM-DKI model at 3 T for clinical characterization of prostate cancer (PCa) and benign prostatic hyperplasia (BPH).
Thirty-two patients with biopsy-proven PCa were recruited for MRI examination (n = 16 scanned at 1.5 T, n = 16 scanned at 3 T). Diffusion-weighted imaging (DWI) with 13 b values (b = 0 to 2000 s/mm up to 3 averages, 1.5 T: TR = 5.774 s, TE = 81 ms and 3 T: TR = 4.899 s, TE = 100 ms), T2-weighted, and T1-weighted imaging were used on the 1.5 T and 3 T MRI scanner, respectively. The IVIM-DKI signal was modeled using the traditional IVIM-DKI model and a novel model in which the total variation (TV) penalty function was combined with the traditional model to optimize non-physiological variations. Paired and unpaired t-tests were used to compare intra-scanner and scanner group differences in IVIM-DKI parameters obtained using the novel and the traditional models. Analysis of variance with post hoc test and receiver operating characteristic (ROC) curve analysis were used to assess the ability of parameters obtained using the novel model (at 1.5 T) and the traditional model (at 3 T) to characterize prostate lesions.
IVIM-DKI modeled using novel model with TV spatial penalty function at 1.5 T, produced parameter maps with 50-78% lower coefficient of variation (CV) than traditional model at 3 T. Novel model estimated higher D with lower D*, f and k values at both field strengths compared to traditional model. For scanner differences, the novel model at 1.5 T estimated lower D* and f values as compared to traditional model at 3 T. At 1.5 T, D and f values were significantly lower with k values significantly higher in tumor than BPH and healthy tissue. D (AUC: 0.98), f (AUC: 0.82), and k (AUC: 0.91) parameters estimated using novel model showed high diagnostic performance in cancer lesion detection at 1.5 T.
In comparison with the IVIM-DKI model at 3 T, IVIM-DKI signal modeled with the TV penalty function at 1.5 T showed lower estimation errors. The proposed novel model can be utilized for improved detection of prostate lesions.
采用高级空间惩罚重建来约束体素内不相干运动（IVIM）-扩散峰度成像（DKI）模型，并研究其是否可以在 1.5 T 为临床诊断前列腺癌（PCa）和良性前列腺增生（BPH）患者提供比 3 T 传统 IVIM-DKI 模型更好的替代方案。
招募了 32 名经活检证实患有 PCa 的患者进行 MRI 检查（16 名患者在 1.5 T 进行扫描，16 名患者在 3 T 进行扫描）。使用 13 个 b 值（b=0 至 2000 s/mm ，平均为 3 次，1.5 T：TR=5.774 s，TE=81 ms；3 T：TR=4.899 s，TE=100 ms）的扩散加权成像（DWI）、T2 加权成像和 T1 加权成像，分别在 1.5 T 和 3 T MRI 扫描仪上进行。通过传统 IVIM-DKI 模型和将总变差（TV）惩罚函数与传统模型相结合的新模型来对 IVIM-DKI 信号进行建模，以优化非生理变化。采用配对和非配对 t 检验比较了新模型和传统模型在 1.5 T 和 3 T 扫描仪上获得的 IVIM-DKI 参数的组内和组间差异。采用方差分析和事后检验以及受试者工作特征（ROC）曲线分析来评估新模型（在 1.5 T 下）和传统模型（在 3 T 下）获得的参数在诊断前列腺病变中的能力。
与 3 T 传统 IVIM-DKI 模型相比，采用 TV 空间惩罚函数的新模型在 1.5 T 下生成的参数图的变异系数（CV）降低了 50%-78%。与传统模型相比，新模型在两种场强下均估计出更高的 D 值，更低的 D*、f 和 k 值。对于扫描仪之间的差异，与 3 T 传统模型相比，1.5 T 新模型估计的 D*和 f 值更低。在 1.5 T 下，肿瘤中的 D 值和 f 值明显低于 BPH 和健康组织，而 k 值明显更高。在 1.5 T 下，新模型估计的 D（AUC：0.98）、f（AUC：0.82）和 k（AUC：0.91）参数在癌症病变检测中具有较高的诊断性能。
与 3 T 传统 IVIM-DKI 模型相比，在 1.5 T 下采用 TV 惩罚函数的 IVIM-DKI 信号的估计误差较低。所提出的新模型可用于提高前列腺病变的检测能力。
