Single-photon emission CT using^99mTc-dimercaptosuccinic acid (DMSA) for characterization of suspected renal masses

Abstract

Cite this article as: Grüning T, Drake BE, Freeman SJ. Single-photon emission CT using 99m Tc-dimercaptosuccinic acid (DMSA) for characterization of suspected renal masses. Br

The diagnostic value of DMSA scan in differentiating functional pseudo-tumors from malignancies in scarred kidneys: case series and literature review

“…FPTs represent a diagnostic challenge and necessitate further radiologic work-up. Even after conducting US and non-contrast CT, some lesions still remain indeterminate [ 14 ]. In one study on CKD patients, 92.5% of the tumor-like lesions evaluated by conventional MRI remained indeterminate [ 13 ].…”

“…The most widely accepted theory suggests that the radiopharmaceutical is bound to plasma proteins and freely filtered by the glomeruli and reabsorbed by renal proximal tubular cells accumulating in the kidney cortex. This indicates the need for both functioning glomeruli and cortical tubules for the isotope to be up taken in cortical tubules [ 14 , 35 , 36 ]. This can explain why there is decreased radiotracer uptake in patients with proximal tubular dysfunction despite normal gross anatomy and normal creatinine clearance [ 35 , 37 ].…”

“…Normally, the functioning renal tissue will pick up the radiotracer, while nonfunctioning tissues, such as renal scars, cysts or neoplasms will have decreased or absent uptake, thus appearing photo-penic [ 10 , 14 ]. DMSA scans of our CKD patients revealed areas of relatively normal or increased uptake corresponding to the FPTs.…”

“…In previous case reports where biopsies of the FPT were done revealing functioning renal tissue, all nodules displayed radiotracer uptake on the scans done preceding excision [ 7 , 8 ]. More recently Gruning et al eluded to this concept in a series of 15 patients with renal masses and showed a high accuracy (100%) at excluding malignancy when uptake is present [ 14 ].…”

“…In patients with CKD, ultrasound (US), non-contrast computed tomography (CT), and conventional magnetic resonance imaging (MRI) are frequently inconclusive in differentiating malignancies from FPT [ 13 ]. On the other hand, Dimercaptosuccinic acid (DMSA) scan uses a non-nephrotoxic radiotracer that is picked up by functioning renal nephrons, thus offers a plausible methodology to diagnose FPTs which have a relatively normal to increased radiopharmaceutical uptake, while neoplasms will display an area of decreased or absent uptake [ 7 , 10 , 14 , 15 ]. Single photon emission computed tomography (SPECT) provides 3D reconstructions of the imaged kidney, leading to definite localization of the suspected mass and especially useful when multiple small FPT’s are present in a complex scarred kidney architecture.…”