A review of 99mTc-sestamibi SPECT/CT for renal oncocytomas: A modified diagnostic algorithm.

99mTc-sestamibi SPECT/CT is a promising nuclear medicine imaging investigation for benign renal lesions such as renal oncocytomas. The purpose of this article is to ) review the current literature on 99mTc-sestamibi SPECT/CT, ) to review to current application of 99mTc-sestamibi SPECT/CT for indeterminate renal lesion imaging, and ) to discuss present limitations and areas for future research. The literature has been reviewed up to April 2022 for articles relating to the application of 99mTc-sestamibi SPECT/CT for benign renal lesions including a recently published systematic review and meta-analysis performed by the authors. One study evaluating 99mTc-sestamibi SPECT alone and five studies evaluating 99mTc-sestamibi SPECT/CT have been performed to date. 99mTc-sestamibi SPECT/CT demonstrates high sensitivity and specificity for detecting benign renal lesions, particularly renal oncocytomas. 99mTc-sestamibi SPECT/CT demonstrates near-perfect specificity for benign and low-grade renal lesions. The optimal quantified threshold ratio for tumor-to-background renal parenchyma radiotracer uptake for a positive result is > 0.6. In this article, we propose a modified diagnostic algorithm for small enhancing renal masses measuring 1-4 cm in which suspected benign lesions after conventional imaging are considered for 99mTc-sestamibi SPECT-CT. In this algorithm, positive studies can be monitored with active surveillance rather than requiring invasive biopsy and/or targeted therapy.