Purpose: This prospective study compared the value of Tc-99m DMSA renal pla
nar scintigraphy with SPECT to detect new renal involvement in patients wit
h repeated episodes of acute pyelonephritis (APN).
Materials and Methods: Children with suspected APN were transferred to our
department for DMSA renal scans. Seventy-two children (ages 1 week to 15 ye
ars) had DMSA planar and SPECT imaging performed twice because of clinical
or laboratory suspicion of repeated APN. In addition, radiographic voiding
cystourethrography was also performed in all cases. The presence of vesicou
reteral reflux (VUR) was graded on a scale of 0 to 5.
Results: New lesions were observed with SPECT in 56 kidneys and with planar
scintigraphy in 38 kidneys. No patients had a negative result of Tc-99m DM
SA renal SPECT who also had a positive Tc-99m DMSA planar result. The degre
e of VUR as related to APN was diagnosed better with SPECT than with planar
scintigraphy (46 compared with 30 and 10 compared with 8, respectively). T
here is a significant difference (P < 0.05) between the diagnostic ability
of these two methods to identify the increased tendency of repeated APN to
occur with high-grade VUR compared with low-grade or no VUR.
Conclusions: High-grade VUR is more commonly associated with renal injury t
han is low-grade or no VUR. If only Tc-99m DMSA renal planar scintigraphy i
s performed, renal scarring may be underestimated. Our results suggest that
Tc-99m DMSA renal SPECT, rather than planar scintigraphy, should be used r
outinely in children with a clinical suspicion of APN, especially for those
with scarred kidneys and high-grade VUR.