الفهرس 
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Abstract
99mTc- DMSA scan is the current gold standard for the detection of renal parenchymal abnormalities, particularly scarring in pyelonephritis Various acquisition techniques, including planar parallel-hole collimator imaging, planar high-resolution parallel-hole collimator imaging, pinhole collimator imaging, SPECT, and pinhole SPECT, have been utilized Planar imaging is the most extensively used technology but is constrained by its two-dimensional information. SPECT is employed in certain centers as it is thought to be more sensitive and add some specificity; although the 3D aspect of SPECT alone suffers from a lack of precision and accuracy in diagnosis due to lack of proper anatomical information, the use of hybrid imaging techniques with SPECT-CT may help in diagnostic accuracy and ultimately patient management In the current study, we assessed the role of 99mTc- DMSA renal cortical scintigraphy planar, SPECT, and SPECT/CT imaging in detecting renal cortical scarring. In concordance with ours, several studies found a higher percentage of cortical defects to be located at the upper and lower poles of both kidneys and attributed this predominant polar distribution of renal cortical scarring to be related to the reflux of infected or sterile urine into compound or refluxing papillae situated at the renal poles A meta-analysis indicated that SPECT DMSA had greater true-positive and false-positive rates than planar DMSA, but the overall test performance is not demonstrably superior to planar DMSA, according to the authors similarly, we found 41 false-positive lesions. In line with our results, found more defects detected by SPECT compared to planar imaging; however, with no statistical significance Several studies had evaluated the value of Tc-99m DMSA renal triple-detector SPECT compared to planar imaging and revealed promising results for SPECT and that high-resolution SPECT imaging improves the ability to detect cortical defects and visualize the asymmetry of cortical thickness the discrepancy in results may be attributed to the better image resolution provided by the triple-detector SPECT with ultra-high-resolution collimators; however, this triple-detector system are currently not widely available. stated that the use of DMSA SPECT/CT can help to identify the etiology of the photopenic defect, for example, due to fetal lobulation, scarring, cyst, or renal tumors concluded that SPECT/CT might add further to reader confidence by delineating renal structures and increasing specificity by providing diagnostic clues to lesions that do not represent scars Tc-99m DMSA uptake in a thin cortex due to hydronephrosis was susceptible to partial volume effects in SPECT that it appears as reduced uptake regions resembling renal scars. In this case, regional uptake defects shown by DMSA scintigraphy may include not only renal scars but also some false positives and other problems such as fetal lobulation and splenic impression according to that, we interpreted our results, where only 5/17 single lesions and 11/40 multiple lesions had been proved to be a scar in the SPECT/CT images while the remaining lesions corresponded to a solitary cortical cyst, either multiple cortical cysts or hydro-nephrotic changes, respectively. Four kidneys with multiple defects in the SPECT/CT images were found to be normal in planar readings, and this was attributed to increased renal background activity and decreased renal function; these figures come in agreement with those of The small sample size, along with the heterogeneous age of the study population, were the current limitations of our study. On the contrary, the advantage of our study was the use of SPECT/CT imaging which helped in reducing false results of SPECT and planar imaging. We recommend further prospective studies with a larger sample size to validate our results; additionally, we recommend the use of SPECT/CT in cases with equivocal readings in planar images as well as in patients with decreased renal function and subsequently raised background activity. In patients with suspected renal cortical scarring, 99mTc- DMSA SPECT/CT scanning proved superior to both planar and SPECT imaging as it decreased the number of false-positive readings of SPECT and the false-negative readings of the planar imaging.