Reproducibility and correlation between quantitative and semiquantitative dynamic and intrinsic susceptibility‐weighted MRI parameters in the benign and malignant human prostate

Abstract

Purpose: To assess the reproducibility of relaxivity-and susceptibility-based dynamic contrast-enhanced magnetic resonance imaging (MRI) in the benign and malignant prostate gland and to correlate the kinetic parameters obtained. Materials and Methods:Twenty patients with prostate cancer underwent paired scans before and after androgen deprivation therapy. Quantitative parametric maps for T 1 -and T 2 *-weighted parameters were calculated (K trans , k ep ,v e , IAUC 60 , rBV, rBF, and R 2 *). The reproducibility of and correlation between each parameter were determined using standard methods at both timepoints.Results: T 1 -derived parameters are more reproducible than T 2 *-weighted measures, both becoming more variable following androgen deprivation (variance coefficients for prostate K trans and rBF increased from 13.9%-15.8% and 42.5%-90.8%, respectively). Tumor R 2 * reproducibility improved after androgen ablation (23.3%-11.8%). IAUC 60 correlated strongly with K trans , v e , and k ep (all P < 0.001). R 2 * did not correlate with other parameters.Conclusion: This study is the first to document the variability and repeatability of T 1 -and T 2 *-weighted dynamic MRI and intrinsic susceptibility-weighted MRI for the various regions of the human prostate gland before and after androgen deprivation. These data provide a valuable source of reference for groups that plan to use dynamic contrastenhanced MRI or intrinsic susceptibility-weighted MRI for the assessment of treatment response in the benign or malignant prostate.

Dynamic Contrast-enhanced CT for Prostate Cancer: Relationship between Image Noise, Voxel Size, and Repeatability

“…the repeatability of DCE MR imaging in prostate cancer, our results in terms of wCV are similar for K trans , with a higher wSD for v e ( 30,32,33 ). Contrary to other studies ( 23,28,31 ), we found that the repeatability of K trans in terms of wCV is the same as v e .…”

Repeatability and sensitivity of measurements in patients with head and neck squamous cell carcinoma at 3T

“…The number of echoes used herein was a result of using in‐phase fat and water signal with echoes acquired with the same gradient polarity, together with SNR threshold. Previous clinical $T_2^{*}$ studies have employed between 4 and 16 echo times 19, 39, 40. In this study, the signal acquired with the gradient echo sequence was found to be dominated by noise for echo times longer than 30 msec.…”

“…It should be noted that the repeatability of any quantitative MRI biomarker might be influenced by a number of methodological factors, such as patient setup, VOI localization, sequence parameters, and shimming method. In terms of this study, the extent of superior–inferior anatomical coverage used was relatively small (<6 cm), and therefore local shimming is expected to be more repeatable in comparison to large field of view studies in other anatomical sites 39. Another limitation of the study was the relatively small number and heterogeneity of tumors imaged (8 primary and 14 metastatic nodal VOIs), with the majority localized in the oropharynx.…”

Spectral clustering applied for dynamic contrast-enhanced MR analysis of time–intensity curves

“…Although, the semi-quantitative method is reproducible, it can be heavily influenced by the selected protocol [9]. Moreover, it is not useful for precisely determining changes in contrast agent concentration, and therefore does not directly yield data on tissue physiology.…”

“…In fact, several studies focusing on this technique have demonstrated the difficulty of reproducing and repeating these physiological parameter measurements [9,12]. Quantitative analysis involves T1 mapping, transformation of signal intensity time curves S(t) into contrast agent concentration time curves C(t), and arterial input function measurement (AIF).…”