Identification of benign from malignant small renal tumors: is there a possible role of T1 mapping?

Differentiating benign from malignant small renal tumors (SRMs) can help to guide clinical decision-making. T1 mapping enables quantitative assessment of T1 relaxation time and may help to evaluate SRMs properties. This study aimed to investigate the possible utility of T1 mapping for identification of SRMs.

The data set used in this retrospective study, consisted of 104 patients with SRMs (≤ 4 cm). 78 malignant and 25 benign ones respectively. Calculated and compared the quantitative variables (including T1 mapping) between different renal tumors. The clinical features qualitative characteristics were subsequently documented. Finally, the logistic regression models were used to identify independent influencing factors. The diagnostic accuracy of independent influencing factors was represented with the area under the receiver operating characteristic curve (AUC).

The pre-contrast T1 mapping (T1) and the ratio of T1 reduction in malignance were higher than those in benign SRMs, while post-contrast T1 mapping was lower (all P < 0.025). In multivariable logistic regression, the tumor necrosis (odds ratio (OR) = 20.636, P = 0.005) and T1 (OR = 2.982, P = 0.002) were independent predictors. For the identification of SRMs, the performance of the model achieving an AUC of 0.793 (95% CI 0.701-0.866) when combining two factors.

Quantitative T1 mapping parameters may be a new potential biomarker for noninvasively distinguishing SRMs.