Three-Tesla dynamic contrast-enhanced MRI: a critical assessment of its use for differentiation of renal lesion subtypes

Perfusion parameters of intravoxel incoherent motion based on tumor edge region of interest in cervical cancer: evaluation of differentiation and correlation with dynamic contrast-enhanced MRI

BACKGROUND

Intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) is a functional magnetic resonance imaging (MRI) sequence.

PURPOSE

To evaluate the value of perfusion parameters derived from IVIM-DWI based on tumor edge region of interest (ROI) in differentiation in cervical cancer and investigate the relationship between IVIM and dynamic contrast-enhanced MRI (DCE-MRI).

MATERIAL AND METHODS

Thirty-three patients with pathologically diagnosed squamous cell carcinoma who underwent IVIM-DWI (nine b-values: 1-1000 s/mm²) and DCE-MRI were retrospectively assessed in this study. Parameters of IVIM (D, f, D*, fD*) and quantitative parameters of DCE-MRI (Ktrans, Kep, Ve) were derived using tumor edge ROI. Mann-Whitney U test was used to compare parameters between pathological grades and receiver operating characteristic (ROC) curves were used. Pearson's correlation coefficient (r) evaluated the correlation between perfusion parameters derived from IVIM and DCE-MRI.

RESULTS

The poorly differentiated group showed the significantly lower D value and the higher f, Ktrans and Kep values than the well-to-moderately differentiated group (P < 0.05). ROC curves indicated that f < 26%, Ktrans <0.38/min, and Kep <1.62/min could differentiate the poorly differentiated group from the well-to-moderately differentiated group (AUC 0.753-0.808). Significantly positive correlations were found between f and Ktrans (r = 0.422, P = 0.014) and between fD* and Ktrans (r = 0.448, P = 0.009).

CONCLUSION

Perfusion parameters derived from IVIM based on tumor edge ROI may offer additional value in differentiation in cervical cancer, and the IVIM perfusion parameters showed moderate positive correlations with quantitative perfusion parameters from DCE-MRI, while f and fD* showed promising significance.

Diagnostic Accuracy of MRI for Detection of Papillary Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVE

The objective of our study was to perform a systematic review and meta-analysis of the diagnostic performance of MRI in differentiation of papillary renal cell carcinoma (RCC) from other renal masses.

MATERIALS AND METHODS

We performed searches of three electronic databases for studies that used MRI techniques to differentiate papillary RCC from other renal lesions. Methodologic quality was assessed, and diagnostic test accuracy was summarized using bivariate random-effects modeling or with construction of a summary ROC (SROC) curve.

RESULTS

Thirteen studies involving 275 papillary RCC lesions and 758 other renal masses met the inclusion criteria. Resulting summary estimates for the performance of MRI to differentiate papillary RCC from other renal lesions were a sensitivity of 79.6% (95% CI, 62.3-90.2%) and specificity of 88.1% (95% CI, 80.1-93.1%). In subgroup analysis, quantitative pooling of seven studies using enhancement in the corticomedullary phase resulted in a sensitivity of 85.6% (95% CI, 67.8-94.4%), specificity of 91.7% (95% CI, 76.0-97.5%), and area under the SROC curve of 0.894. Four studies used tumor appearance on T2-weighted imaging to detect papillary RCC, and results showed a pooled sensitivity of 89.9% (95% CI, 73.0-96.7%) and specificity of 84.9% (95% CI, 69.0-93.4%). Three studies used signal loss on T1-weighted in-phase imaging to detect papillary RCC but marked heterogeneity precluded pooling.

CONCLUSION

Meta-analysis supports moderate sensitivity and excellent specificity of quantitative enhancement in the corticomedullary phase for differentiating papillary RCC from other tumors. The accuracy of combining enhancement and T2 signal-intensity characteristics merits further evaluation as a potential aid for management decisions.

Dynamic Contrast-enhanced MRI in Renal Tumors: Common Subtype Differentiation using Pharmacokinetics

Preoperative renal tumor subtype differentiation is important for radiology and urology in clinical practice. Pharmacokinetic data (K^trans & V_e, etc.) derived from dynamic contrast-enhanced MRI (DCE-MRI) have been used to investigate tumor vessel permeability. In this prospective study on DCE-MRI pharmacokinetic studies, we enrolled patients with five common renal tumor subtypes: clear cell renal cell carcinoma (ccRCC; n = 65), papillary renal cell carcinoma (pRCC; n = 12), chromophobic renal cell carcinoma (cRCC; n = 9), uroepithelial carcinoma (UEC; n = 14), and fat-poor angiomyolipoma (fpAML; n = 10). The results show that K^trans of ccRCC, pRCC, cRCC, UEC and fpAML (0.459 ± 0.190 min⁻¹, 0.206 ± 0.127 min⁻¹, 0.311 ± 0.111 min⁻¹, 0.235 ± 0.116 min⁻¹, 0.511 ± 0.159 min⁻¹, respectively) were different, but V_e was not. K^trans could distinguish ccRCC from non-ccRCC (pRCC & cRCC) with a sensitivity of 76.9% and a specificity of 71.4%, respectively, as well as to differentiate fpAML from non-ccRCC with a sensitivity of 100% and a specificity of 76.2%, respectively. Our findings suggest that DCE-MRI pharmacokinetics are promising for differential diagnosis of renal tumors, especially for RCC subtype characterization and differentiation between fpAML and non-ccRCC, which may facilitate the treatment of renal tumors.

Diagnostic performance of diffusion-weighted magnetic resonance imaging in differentiating human renal lesions (benignity or malignancy): a meta-analysis

PURPOSE

This study aims to quantitatively evaluate the potential of diffusion-weighted magnetic resonance imaging (DW-MRI) for differentiating malignant and benign human renal lesions.

MATERIALS AND METHODS

A systematic literature was performed to identify previous research related to the diagnostic performance of DW-MRI for determining whether human renal lesions were benign or malignant. ADC values were extracted from normal renal tissue and different lesion types. Data were extracted to assess the diagnostic performance of DW-MRI for differentiating malignant and benign human renal lesions, as well as running threshold effect and heterogeneity.

RESULTS

Nine publications with 11 subsets were eligible for data extraction and diagnostic performance calculation. A total of 988 apparent diffusion coefficient (ADC) measurements were included. The differences in ADC values between benign lesions (2.47 ± 0.81 × 10(-3) mm(2)/s) and malignant lesions (1.81 ± 0.41 × 10(-3) mm(2)/s) were statistically significant (P < 0.001). The diagnostic odds ratio, the overall positive, negative likelihood ratios, pooled weighted sensitivity and specificity with 95% CI were 20.05 (95% CI 12.56-32.02), 3.32 (95% CI 2.13-5.18), 0.20 (95% CI 0.15-0.27), 88% (95% CI 0.84-0.91) and 72% (95% CI 0.67-0.76), respectively. The area under the curve of the summary receiver operating characteristic was 0.90.

CONCLUSIONS

This meta-analysis indicated that DW-MRI had a relatively good diagnostic accuracy in differentiating malignant and benign human renal lesions. We preliminarily recommend that DW-MRI is performed with a maximum b value ranging from 800 to 1000 s/mm(2) at 3.0 T for imaging protocol, and that DW-MRI should be used with caution when the study population includes children.

[Functional magnetic resonance imaging of the kidneys]

Interest in functional renal magnetic resonance imaging (MRI) has significantly increased in recent years. This review article provides an overview of the most important functional imaging techniques and their potential clinical applications for assessment of native and transplanted kidneys, with special emphasis on the clarification of renal tumors.