To characterize small renal cell carcinoma using diffusion relaxation correlation spectroscopic imaging and apparent...

Area of Science:

• Radiology and Imaging
• Oncology
• Medical Physics

Background:

• Small renal cell carcinoma (RCC) presents diagnostic challenges for subtype classification and grade differentiation.
• Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) histogram analysis are established MRI techniques for RCC assessment.
• Diffusion-relaxation correlation spectroscopic imaging (DR-CSI) offers a novel approach to characterize tissue microenvironment.

Purpose of the Study:

• To evaluate the efficacy of DR-CSI in distinguishing subtypes of small RCC (clear cell RCC vs. non-clear cell RCC).
• To assess the capability of DR-CSI in differentiating high-grade from low-grade small RCC.
• To compare the performance of DR-CSI with ADC histogram analysis for these tasks.

Main Methods:

• Retrospective analysis of MRI data from 61 patients with small RCC (<4 cm).
• Acquisition of multi-b, multi-TE DWI data; manual delineation of regions of interest (ROIs) on solid tumors.
• Generation of D-T2 spectra, segmentation into 5 compartments (V_A-V_E), and calculation of ADC histogram parameters (ADC 90th, 10th, median, etc.).
• Statistical comparison of MRI metrics between ccRCC/non-ccRCC and high/low-grade groups; Receiver Operator Curve (ROC) analysis.

Main Results:

• Clear cell RCC (ccRCC) exhibited significantly higher ADC 90th, 10th, median, and lower DR-CSI V_B compared to non-ccRCC.
• High-grade RCC showed significantly lower ADC 90th, median, and higher V_B compared to low-grade RCC.
• DR-CSI V_B achieved the highest AUC (0.861) and specificity (0.882) for ccRCC identification.
• ADC 90th demonstrated the highest AUC (0.726) and specificity (0.786) for high-grade RCC differentiation, with V_B showing moderate performance (AUC 0.715).

Conclusions:

• DR-CSI shows potential for improved accuracy in subtype classification of small renal cell carcinoma.
• DR-CSI performance for grading small RCC was comparable to, but not superior to, ADC histogram analysis.
• DR-CSI V_B is a promising biomarker for distinguishing ccRCC from non-ccRCC.