Kidney Scar Detection
Girl, 7 year old with history of recurrent UTI. Ultrasound compatible with asymmetric renal size and parenchymal thinning in the right side. At left, positive UVR in the right kidney (arrow), grade III approximately, in the international classification during the direct cystography. At right, note severe defects in both poles of the right kidney (arrows), consistent with sequelae, loss of volume and function (29%). The left kidney is normal and compensatory as far as function (71%).
It has been reported that in Grade I the frequency of scars reaches 23%; in Grade II, 50%; in Grade III, 77%; in Grade IV, 100% and in Grade V, 100%.
Yiee JH et al., on DMSA scan, found in 29 patients, 10% scar-free, 62% had unilateral scars, and 28% had bilateral scars. In children with vesicoureteral reflux, those with bilateral scarring have a significantly lower creatinine clearance than those with unilateral scarring. The severity of scar grade alone does not predict overall creatinine clearance with short-term follow-up.
Brenner M et al., reported that DMSA renal cortical imaging using dual-head SPECT offers no statistically significant diagnostic advantage over planar imaging for detection of cortical defects.
This author comments "Animal studies, using histology as a reference standard, report high sensitivity and high specificity for the diagnosis of pyelonephritis in piglets. Using planar imaging and a converging collimator, Rushton et al. reported 87% sensitivity and 97% specificity. Parkhouse et al. reported a sensitivity of 100% and specificity of 89% using a multipurpose parallel-hole collimator. Using SPECT, Giblin et al. [14] found a sensitivity of 97% and specificity of 93%. The only comparative piglet study was that of Majd et al., who reported 99mTc-DMSA SPECT scintigraphy to be 92% sensitive and 82% specific compared with pinhole imaging, which was 83% sensitive and 95% specific" (3).
References:
1 Rossleigh MA. Renal infection and vesico-ureteric reflux. Semin Nucl Med. 2007 Jul;37(4):261-8.
2 Yiee JH, DiSandro M, Wang MH, Hittelman A, Baskin LS. Does severity of renal scarring on DMSA scan predict abnormalities in creatinine clearance?. Urology. 2010 Jul;76(1):204-8. Epub 2010 May 15.
3
Brenner M, Bonta D, Eslamy H, Ziessman HA. Comparison of 99mTc-DMSA dual-head
SPECT versus high-resolution parallel-hole
planar imaging for the detection of renal cortical defects. AJR Am J Roentgenol.
2009 Aug;193(2):333-7.