99mTc-dimercaptosuccinic Acid Research Articles

Congenital solitary functioning kidney: evaluations to do which, when, and how

Congenital solitary functioning kidney (CSFK) is characterized by an anatomical or functional absence of one kidney from birth. When suspected on perinatal ultrasonography (US), repeat US after birth should be performed for confirmation. Although postnatal 99mTc-dimercaptosuccinic acid scintigraphy (DMSA scan) is the gold standard for confirming CSFK, it carries the risk of radiation exposure; US alone is sufficient when performed by an experienced radiologist. One-third of patients with CSFK have additional congenital anomalies of the kidney and urinary tract at the solitary functioning kidney, the most common of which is vesicoureteral reflux. As evidence regarding vesicoureteral reflux with normal kidney US is correlated with significant urinary tract infection is lacking, voiding cystourethrogram may be considered in patients with CSFK with abnormal US findings. Furthermore, approximately 30% of patients with CSFK have extrarenal malformations. Moreover, up to 10% of them have syndromic features. In particular, examining for female genitalia malformations, which can have potential for complications from untreated obstructive malformations, is important. In conclusion, DMSA scan and voiding cystourethrogram are not necessary for all patients with CSFK, and the risk of each patient should be assessed to determine which test is needed during follow-up. The presence of extrarenal manifestations should also always be considered.

The role of nuclear medicine techniques; Tc-99m-labeled dimercaptosuccinic acid, diethylenetriaminepentaacetic acid, and mercaptoacetyltriglycine scintigraphies in pediatric surgery

The purpose of this review is to highlight the pivotal role of nuclear medicine in pediatric surgery, specifically in the diagnosis and management of nephro-urological conditions. This review focuses on the applications and advantages of three key nuclear medicine techniques: Tc-99m dimercaptosuccinic acid (DMSA), Tc-99m diethylenetriaminepentaacetic acid (DTPA), and Tc-99m mercaptoacetyltriglycine (MAG3) scintigraphies. These imaging modalities are crucial for providing detailed anatomical and functional information with minimal invasiveness, essential for evaluating congenital anomalies, urinary tract infections, and obstructive uropathies in children. DMSA Scintigraphy is established as the gold standard for detecting renal cortical scarring and assessing functional renal parenchymal damage. It offers superior sensitivity and specificity compared to other imaging techniques, making it indispensable for identifying renal scars from recurrent urinary tract infections or pyelonephritis. DTPA Scintigraphy is critical for measuring glomerular filtration rate (GFR) and analyzing renogram curves, providing quantitative assessments of renal function. It effectively evaluates renal perfusion and identifies perfusion defects and renal ischemia, essential for managing conditions like renal artery stenosis and unilateral kidney disease. MAG3 Scintigraphy excels in dynamic renal scintigraphy, particularly in patients with impaired renal function. It provides high-quality images and superior diagnostic capability, making it invaluable for assessing ureteropelvic junction obstruction and other obstructive uropathies in pediatric patients. The review concludes by emphasizing the integration of these scintigraphy techniques with SPECT/CT, enhancing diagnostic accuracy and providing comprehensive anatomical and functional insights. Despite concerns regarding radiation exposure, measures such as dose optimization and advanced imaging techniques ensure safety and efficacy in pediatric applications.

Review of the Clinical and Technical Aspects of 99mTc-Dimercaptosuccinic Acid Renal Imaging: The Comeback "Kit".

99mTc-labeled dimercaptosuccinic acid (99mTc-DMSA) imaging is a well-established and highly sensitive method for the diagnosis of several renal cortical disorders affecting children and adults. Beginning in 2014, 99mTc-DMSA availability was severely impaired when it was added to the Drug Shortages List of the U.S. Food and Drug Administration and was commercially unavailable thereafter. The agent shortage negatively impacted practitioners' ability to evaluate renal cortical defects in children and adults and changed renal imaging practice. A survey among pediatric nuclear medicine clinicians confirmed the clinical need for 99mTc-DMSA. Finally, in early 2023 the Food and Drug Administration again approved 99mTc-DMSA in the United States. During the 99mTc-DMSA shortage, established practitioners may not have had the opportunity of using 99mTc-DMSA as they were accustomed in their experience. Also, newer imaging specialists and referring physicians and technologists may not have benefited from having 99mTc-DMSA in their training. Therefore, it is time to bring back 99mTc-DMSA into the armamentarium of imaging methods available to evaluate regional cortical renal function.

Renal Cortical Imaging with Tc-99m DMSA in Children: An Institutional Review.

Background Urinary tract infection (UTI) is one of the commonly encountered conditions in children. Dimercaptosuccinic acid (DMSA) scintigraphy is widely advocated for functional and morphological evaluation of the renal cortex including parenchymal defect. Moreover, only a small percentage of renal defects are detected by ultrasound. We aimed to examine DMSA scintigraphy of children and identify factors associated with cortical defect. Methods Patients aged ≤ 18 years old who underwent DMSA scintigraphy (November 18, 2019-February 2, 2023, 30 children) were included. All children received intravenous injections of 99m Tc-DMSA followed by static planar and single-photon-emission computed tomography imaging at 3 hours. Cortical findings and differential functions of the worst affected kidney were graded accordingly. Grade I has no more than two cortical defects, grade II has more than two cortical defects with normal parenchyma between the defects, while grade III is when generalized damage is noted, and grade IV is when a shrunken kidney is seen with no DMSA uptake. Normal functioning kidney is when the relative function at 45 to 55%, mildly reduced function at 40 to 44%, and substantially impaired function at 10 to 39%, while nonfunctioning is when the differential split renal function < 10%. All data were then statistically analyzed. Results Majority was female (53%). The mean age was 5.85 years. UTI episodes were 73%. Twenty-two children had congenital urinary tract anomalies. All patients with vesicoureteric refluxes (VURs) had positive defects. Scintigraphy showed abnormalities in 17 children affecting unilateral (64%) or both kidneys (36%). There were 17 children (57%) respectively in the abnormal DMSA scan findings category with normal until significant impairment of the functioning kidney category. VURs were significantly associated with abnormal scintigraphy ( p < 0.05). A significant association was found between abnormal DMSA scan findings and differential renal function ( p < 0.05). Conclusion Significant association was noted between VURs and abnormal DMSA scintigraphy, abnormal DMSA scan findings, and impaired differential renal function. Special consideration should be given to these cases.

99mTc-DMSA and 99mTc-DTPA identified renal dysfunction due to microplastic polyethylene in murine model

In the previous study (Im et al., 2022), we revealed microplastic (MP) was accumulated and cleared through the kidneys via PET imaging. Here, we aimed to identify the renal dysfunction due to polyethylene (PE) MP in the kidney tissue. Mice were exposed to 100 ppm (∼equivalent to 0.1 mg/mL)/100 μL of PE for 12 weeks (n = 10). PE uptake in the kidney tissues was confirmed using confocal microscopy. QuantSeq analysis was performed to determine gene expression. Renal function assessment was performed using 99mTc-Diethylene triamine penta acetic acid or 99mTc-Dimercaptosuccinic acid. Measurement of creatinine, BUN, and albumin levels in serum and urine samples was also estimated. [18F]-FDG was also acquired. PE increased expression of Myc, CD44, Programmed Death-Ligand 1 (PD-L1), and Hypoxia-Inducible Factor (HIF)-1α, which indicates a potential link to an increased risk of early-onset cancer. An increase in glucose metabolism of [18F]-FDG were observed. We assessed renal failure using 99mTc-Diethylene triamine penta acetic acid and 99mTc-Dimercaptosuccinic acid scintigraphy to determine the renal function. Renal failure was confirmed using serum and urine creatinine, serum blood urea nitrogen levels, serum albumin levels, and urine albumin levels in PE exposed mice, relative to the control. In sum, PE exposure induced renal dysfunction in a murine model.

Investigation of the Effects of N-acetylcysteine and Selenium on Vesicoureteral Reflux Nephropathy: An Experimental Study

IntroductionThis study aimed to investigate the effects of N-acetylcysteine (NAC) and selenium (Se) on vesicoureteral reflux (VUR) nephropathy. MethodsA total of 44 rabbits in 7 groups, namely group 1 (Control), group 2 (VUR + sterile urine), group 3 (VUR + sterile urine + NAC), group 4 (VUR + sterile urine + Se), group 5 (VUR + infected urine), group 6 (VUR + infected urine + NAC) and group 7 (VUR + infected urine + Se), were used. 99mTc Dimercaptosuccinic acid renal scan (DMSA), cystogram and urine culture were performed both at the beginning and end of the study. Left VUR was created surgically, and E. coli was inoculated in infected urine groups. NAC and Se were administered daily for 21 days. Malondialdehyde (MDA) measurement, inflammatory response scores (IRSs), and cicatrization response scores (CRSs) in renal tissues were evaluated. ResultsVUR did not reduce left renal uptake values in neither group 2 nor group 5. MDA levels of the left kidney were significantly higher in group 5 compared to group 1 (p = 0.001). There was no significant difference in MDA levels between group 5 and group 6, and between group 5 and group 7. Left kidney IRSs were found to be higher in all other groups except group 2 compared to the control group (p < 0.001). Left kidney CRSs were significantly higher in group 5 compared to group 2 (p = 0.026), group 6 (p < 0.001) and group 7 (p = 0.006). ConclusionA decrease in renal functions was not observed in VUR, even if there was infection. When CRSs were evaluated, NAC and Se had protective effects in terms of scar formation in VUR nephropathy. Type of StudyExperimental animal study. Levels of EvidenceN/A.

First episode of febrile urinary tractinfection in children, detection and risk factors of kidney scarring: Aprospective cohort study.

This prospective study aimed to evaluate the characteristics and findings of children who presented with acute pyelonephritis (APN) and to determine the independent risk factors for kidney scarring. Patients who satisfied the following criteria were enrolled in the study: first known episode of APN; at least two of the following findings: fever ≥ 38.5 °C, white blood cell count ≥ 10,000/mm3, erythrocyte sedimentation rate ≥ 20 mm/h, C-reactive protein ≥ 20 mg/dL; absence of congenital abnormalities or other kidney and systemic diseases, except vesicoureteral reflux (VUR); no APN relapses until the time of kidney scar detection. 99mTc-Dimercaptosuccinic acid kidney scintigraphy (99mTc-DMSA) was performed at admission, along with a kidney ultrasound. Follow-up 99mTc-DMSA took place after 6 months. Radiographic cystourethrography for VUR detection and grading was performed 1 month after the acute infection. We enrolled 70 children in the study. The kidney ultrasound failed to diagnose more than half of the cases of APN. VUR was found in 21.5% of children. 75% had findings of APN in the acute phase through 99mTc-DMSA, while in the second 99mTc-DMSA, there was a complete remission in 68% of them. Scars were observed more frequently in older children, children with VUR grade ≥ III, and children not on antibiotic prophylaxis. VUR did not appear to be associated with the first episode of APN, and children older than 1 year of age had a higher risk of scarring. Antibiotic prophylaxis may prevent kidney scarring due to host immunomodulatory effects, but more studies are needed so that conclusions can be drawn.

The Intrarenal Reflux Diagnosed by Contrast-Enhanced Voiding Urosonography (ceVUS): A Reason for the Reclassification of Vesicoureteral Reflux and New Therapeutic Approach?

Vesicoureteral reflux (VUR) is defined as the urine backflow from the urinary bladder to the pyelo-caliceal system. In contrast, intrarenal reflux (IRR) is the backflow of urine from the renal calyces into the tubulointerstitial space. VURs, particularly those associated with IRR can result in reflux nephropathy when accompanied by urinary tract infection (UTI). The prevalence of IRR in patients with diagnosed VUR is 1-11% when using voiding cystourethrography (VCUG), while 11.9-61% when applying the contrast-enhanced voiding urosonography (ceVUS). The presence of IRR diagnosed by VCUG often correlates with parenchymal scars, when diagnosed by a 99mTc dimercaptosuccinic acid scan (DMSA scan), mostly in kidneys with high-grade VURs, and when diagnosed by ceVUS, it correlates with the wide spectrum of parenchymal changes on DMSA scan. The study performed by both ceVUS and DMSA scans showed IRRs associated with non-dilated VURs in 21% of all detected VURs. A significant difference regarding the existence of parenchymal damage was disclosed between the IRR-associated and IRR-non-associated VURs. A higher portion of parenchymal changes existed in the IRR-associated VURs, regardless of the VUR grade. That means that kidneys with IRR-associated VURs represent the high-risk group of VURs, which must be considered in the future classification of VURs. When using ceVUS, 62% of places where IRR was found were still unaffected by parenchymal changes. That was the basis for our recommendation of preventive use of long-term antibiotic prophylaxis until the IRR disappearance, regardless of the VUR grade. We propose a new classification of VURs using the ceVUS method, in which each VUR grade is subdivided based on the presence of an IRR.

99mTc-DMSA renal cortical scanning: a comparison of planar, SPECT, and SPECT/CT imaging for the detection of renal cortical scarring

BackgroundThe best way to assess renal cortical scarring is planar scintigraphy with 99mTc-dimercaptosuccinic acid (DMSA), while the value of single-photon emission computed tomography/computed tomography (SPECT/CT) is not well validated. The aim of the present study was to assess the value of planar, SPECT, and SPECT/CT scanning using 99mTc-DMSA in detecting renal cortical scarring.MethodsPatients with clinically suspected renal cortical scar were included in this prospective cohort. 99mTc-DMSA Planar images were obtained approximately 3–4 h after intravenous injection (IV) of 185 MBq of the tracer. SPECT/CT scans were obtained immediately after the planar ones. An expert nuclear medicine doctor who was unaware of the patient's clinical history or any previous imaging results analyzed the images. Each kidney was given a score of 0 for no obvious defects, 1 for equivocal lesions, 2 for a single defect, 3 for several defects, and 4 for non-visualized/non-functioning kidney (in CT images). The results of each method were then compared to each other.ResultsOne hundred eighty-six kidneys from ninety-three individuals were eligible for assessment. Planar scans detected 21 kidneys with equivocal lesions, 5 with single and 7 with multiple defects. SPECT scans detected 17 kidneys with single and 40 with multiple defects, while SPECT/CT scans revealed 5 with single and 11 with multiple defects. Only 5 of the 17 kidneys with single defects diagnosed by SPECT imaging had a scar in the SPECT/CT scans, whereas the remaining 12 had a solitary cortical cyst in the CT images. Only 11 of 40 kidneys with multiple defects on SPECT were shown to have a scar in the corresponding SPECT/CT images, whereas the rest matched to either hydro-nephrotic changes or multiple cortical cysts. Four kidneys with multiple defects on the SPECT/CT images were normal in the planar readings, were ascribed to an increase in renal background activity and a reduction in renal function.ConclusionsIn cases with suspected renal cortical scar, 99mTc-DMSA SPECT/CT scanning outperformed both planar and SPECT imaging by reducing the number of false-positive SPECT readings and false-negative planar readings.

Optimization of radioprotective dose of Juglans nigra leaf extract using response surface methodology

J. nigra leaf contains mixture of various pharmacologically active compounds and it is assumed that they may have the potential radioprotective effect. The purpose of this work was to predict radioprotective doses by correlating changes in organ distribution of radiopharmaceuticals with extract dose levels and rat body weight using response surface methodology (RSM) based on a second-order polynomial equation. The extract was administered daily by oral gavage to rats at dose of 6.9, 10.3, or 13.7 mg kg−1 body weight (bw) day−1 for 10 days. On the eleventh day, 0.1 ml of the one radiopharmaceutical (Na99mTcO4, 99mTc-dimercaptosuccinic acid and 99mTc-tin colloid) was injected into the tail vein. The statistical parameters: the coefficient of determination (0.81–0.95), the coefficient of variation (3.05–11.1), the adequate precision (8.82–19.12) and the mean relative percentage deviation (± 2.3–8.2) were indicated the precision and reliability of RSM. Using RSM, the predicted daily dose of leaf extract ranging from 11.19 to 11.99 mg kg−1 bw may be considered as an optimal daily radiopotective dose for protection of organs from radiation in cases of planned radiation exposures.

Posterior urethral valve in thai boys

BackgroundPosterior urethral valve (PUV) is the most common congenital bladder outlet obstruction in boys, causing renal damage beginning in utero. There are scarce data from Thailand regarding the long-term outcomes of PUV in boys, thus the aim of this study was to examine the presentation, clinical course, complications, outcomes and renal survival in PUV boys.MethodsWe reviewed the medical records of PUV boys treated at the Pediatric Nephrology Clinic, Prince of Songkla University, Thailand, over a 30-year-period.ResultsSeventy-seven PUV boys were identified, with a median age at diagnosis of 4.8 months. The most common presentations were urinary tract infection (UTI), poor urine stream and urinary dribbling in 26 (33.8%), 19 (24.7%) and 11 (14.3%) boys, respectively. Renal ultrasound results in 70 boys showed 8 (11.4%) unilateral and 56 (80%) bilateral hydronephroses. Of 72 voiding cystourethrograms, 18 (25.0%) showed unilateral and 22 (30.6%) bilateral vesicoureteral refluxes. 99mTc dimercaptosuccinic acid renal scans in 30 boys showed 12 (40%) unilateral and 8 (26.7%) bilateral renal damage. Fifty-nine (76.6%) boys had 149 UTIs; 42 (54.4%) had recurrent UTI. Forty-eight boys had valve ablation at the median age of 30.3 months. 22 boys (28.6%) developed chronic kidney disease (CKD) at a median age of 15.0 years.ConclusionOf 77 PUV Thai boys, UTI was the most common presentation. Recurrence of UTI and CKD was the most common consequence. Lifelong follow-up for renal and bladder functions is essential for all PUV patients.

Successful rescue pneumovesicoscopic surgery for post-Deflux® vesicoureteral junction obstruction.

Vesicoureteral junction (VUJ) obstruction after Deflux® subureteral injection for vesicoureteral reflux (VUR) is rare and minimally invasive management has not been reported. This work investigated the patients who underwent Deflux® injection for VUR and identified those with subsequent VUJ obstruction. Medical records of matched patients from October 2003 to March 2022 were reviewed, and parameters were retrospectively studied. All patients underwent Deflux® injection. The injection was performed under general anesthesia using the same manner. For patients complicated with VUJ obstruction, the symptoms, signs, management, images, renal ultrasounds, Tc-99m dimercaptosuccinic acid renal scintigraphy, histology of VUJ region, and outcomes were documented and reported. VUJ stenosis was diagnosed by performing renal ultrasound and magnetic resonance imaging. Totally 407 patients (554 ureterorenal units) received Dx/HA injections for VUR. VUJ obstruction was found in three patients (four ureterorenal units). Originally, three were grade V VUR, and one was grade IV. The repeated injection was not a risk factor for VUJ obstruction. The overall incidence of VUJ obstruction post-Dx/HA injection was 0.7% by ureter. The incidences were 0%, 0.75%, and 2.25% for grade I-III, IV, and V VUR, respectively. After the initial conversion case of pneumovesicoscopic ureteral reimplantation, the procedure was performed smoothly and successfully in the two following cases. Pneumovesicoscopic ureteral reimplantation offers an alternative for VUJ obstruction following Dx/HA injection for VUR. Fibrosis and foreign-body reaction may influence the feasibility. High-grade VUR and young age of injection were related to VUJ obstruction.

Usefulness of preset count acquisition in pediatric 99m Tc-DMSA planar imaging.

This study was aimed at determining the minimum acquisition count to provide diagnosable image quality (DIQ) and investigating the usefulness of preset count acquisition (PCA) for planar images of pediatric 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy. First, we calculated a coefficient of variation (CV) for DIQ with the shortest acquisition time through visual evaluation in 12 pediatric patients who underwent 99mTc-DMSA scintigraphy. Second, a minimum acquisition count to achieve the CV for DIQ was determined with the single regression analysis using CV as an explanatory variable and the total acquisition count as an objective variable in 81 pediatric patients. Finally, we compared PCA images based on the minimum acquisition count and preset time acquisition (PTA) images for 5min in terms of the acquisition time, CV, and renal uptake ratio in another 23 pediatric patients. The visual evaluation showed that the CV corresponding to DIQ with the shortest acquisition time was 27.1%. The total acquisition count corresponding to DIQ was revealed to be 299,764 in the single regression analysis and was determined to be 300,000 after rounding. The CV and its standard deviation in PCA at 300,000 counts and PTA for 5min were 26.4 ± 0.6% and 24.8 ± 1.3%, respectively. The standard deviation of CV in PCA at 300,000 counts was smaller than that in PTA for 5min, indicating little variation in image quality between cases. The acquisition time in PCA at 300,000 counts (3.1 ± 0.7min) was shorter than that in PTA for 5min (5.0 ± 0.0min). The intraclass correlation coefficient between renal uptake ratios for PCA and PTA was 0.98, indicating an extremely high concordance. The minimum acquisition count required for the DIQ was 300,000. In addition, PCA at 300,000 counts was demonstrated to be useful by providing stable image quality at the shortest acquisition time.

Contrast-enhanced ultrasound for the diagnosis of acute pyelonephritis in pediatric patients with urinary tract infection: A feasibility study.

This study aimed to assess the feasibility of contrast-enhanced ultrasound (CEUS) for the diagnosis of acute pyelonephritis (APN) in pediatric patients with febrile urinary tract infection (UTI). Between March 2019 and January 2021, study participants with suspected UTI were assessed for APN using ultrasound. Parenchymal echogenicity changes, renal pelvis dilatation, and the presence of a focal suspected lesion were assessed using conventional grayscale ultrasound. The presence and location of a decreased perfusion area were evaluated using color Doppler ultrasound (CDUS) and CEUS. Agreement between each ultrasound examination and a 99mTc‒dimercaptosuccinic acid (DMSA) scan was assessed using the κ value, and the most visible period of the lesion was evaluated using CEUS. This study enrolled 21 participants (median age, 8.0 months; range, 2.0-61.0 months) with isolated urinary tract pathogens. Five increased parenchymal echotextures (11.9%) and 14 renal pelvic dilatations (33.3%) were confirmed, but no focal lesions were detected on the grayscale images. CDUS and CEUS showed decreased local perfusion suggestive of APN in two and five kidneys, respectively. DMSA scan showed substantial agreement with CEUS findings (κ = 0.80, P = 0.010), but other grayscale and CDUS findings did not agree with DMSA scan results (P > 0.05). All lesions were best observed in the late parenchymal phase on CEUS. CEUS can reveal renal perfusion defects in pediatric patients with suspected APN without radiation exposure or sedation; therefore, CEUS may be a feasible and valuable diagnostic technique.

Acquisition time reduction in pediatric 99mTc‐DMSA planar imaging using deep learning

Given the potential risk of motion artifacts, acquisition time reduction is desirable in pediatric 99m Tc-dimercaptosuccinic acid (DMSA) scintigraphy. The aim of this study was to evaluate the performance of predicted full-acquisition-time images from short-acquisition-time pediatric 99m Tc-DMSA planar images with only 1/5th acquisition time using deep learning in terms of image quality and quantitative renal uptake measurement accuracy. One hundred and fifty-five cases that underwent pediatric 99m Tc-DMSA planar imaging as dynamic data for 10min were retrospectively collected for the development of three deep learning models (DnCNN, Win5RB, and ResUnet), and the generation of full-time images from short-time images. We used the normalized mean squared error (NMSE), peak signal-to-noise ratio (PSNR), and structural similarity index metrics (SSIM) to evaluate the accuracy of the predicted full-time images. In addition, the renal uptake of 99m Tc-DMSA was calculated, and the difference in renal uptake from the reference full-time images was assessed using scatter plots with Pearson correlation and Bland-Altman plots. The predicted full-time images from the deep learning models showed a significant improvement in image quality compared to the short-time images with respect to the reference full-time images. In particular, the predicted full-time images obtained by ResUnet showed the lowest NMSE (0.4 [0.4-0.5] %) and the highest PSNR (55.4 [54.7-56.1] dB) and SSIM (0.997 [0.995-0.997]). For renal uptake, an extremely high correlation was achieved in all short-time and three predicted full-time images (R2 >0.999 for all). The Bland-Altman plots showed the lowest bias (-0.10) of renal uptake in ResUnet, while short-time images showed the lowest variance (95% confidence interval: -0.14, 0.45) of renal uptake. Our proposed method is capable of producing images that are comparable to the original full-acquisition-time images, allowing for a reduction of acquisition time/injected dose in pediatric 99m Tc-DMSA planar imaging.

Imaging of Intrathoracic Ectopic Kidney

The intrathoracic kidney is one of the rare causes of the congenital ectopic kidney. The present study discusses a case referred to our clinic with a pre-diagnosis of renal agenesis and a diagnosis of the intrathoracic ectopic kidney. The case is a 9-year-old patient who applied to our clinic complaining of abdominal pain. The left kidney could not be shown in the abdominal ultrasonography for the patient's abdominal pain. In the Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy performed on this, the left kidney was detected far above its normal localization. On the thorax plus upper abdominal, the patient's computed tomography showed that the left kidney was intrathoracically located and the diaphragmatic hernia. The left kidney may not be visualized on ultrasonography in the patient. Therefore, the ectopic kidneys should be visualized by Tc-99m DMSA scintigraphy. In selected cases, computed tomography should be used to determine the proper localization of the intrathoracic kidney and whether there is a diaphragmatic hernia.

Tc-99m DMSA SPECT for Follow-Up of Non-Operative Treatments in Renal Injuries: A Prospective Single-Center Study.

The assessment of cortical integrity following renal injuries with planar Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy depends on measuring relatively decreased cortical uptake (i.e., split renal function [SRF]). We analyzed the additive values of the volumetric and quantitative analyses of the residual cortical integrity using single-photon emission computed tomography (SPECT) compared to the planar scintigraphy. This prospective study included 47 patients (male:female, 32:15; age, 47 ± 22 years) who had non-operatively managed renal injuries and underwent DMSA planar and SPECT imaging 3-6 months after the index injury. In addition to planar SRF, SPECT SRF, cortical volume, and absolute cortical uptake were measured for the injured kidney and both kidneys together. The correlations of planar SRF with SPECT SRF and those of SRF with volumetric/quantitative parameters obtained with SPECT were analyzed. The association of SPECT parameters with renal function, grades of renal injuries, and the risk of renal failure was also analyzed. SPECT SRF was significantly lower than planar SRF, with particularly higher biases in severe renal injuries. Planar and SPECT SRF (dichotomized with a cutoff of 45%) showed 19%-36% of discrepancies with volumetric and quantitative DMSA indices (when dichotomized as either high or low). Absolute cortical uptake of the injured kidney best correlated with glomerular filtration rate (GFR) at follow-up (ρ = 0.687, P < 0.001) with significant stepwise decreases by GFR strata (90 and 60 mL/min/1.73 m²). Total renal cortical uptake was significantly lower in patients with moderate-to-high risk of renal failure than those with low risk. However, SRF did not reflect GFR decrease below 60 mL/min/1.73 m² or the risk of renal failure, regardless of planar or SPECT (count- or volume-based SRF) imaging. Quantitative measurements of renal cortical integrity assessed with DMSA SPECT can provide more clinically relevant and comprehensive information than planar imaging or SRF alone.

Localization of Pyelonephritis by 68Ga-FAPI PET CT.

Fibroblast activation protein inhibitor (FAPI) is a quinoline-based membrane-bound glycoprotein enzyme that is not usually expressed in normal adult tissues, except for the myometrium and sometimes the pancreas. Its expression increases in inflammation and cancer-associated fibroblasts (CAF). As FAPI is a new molecule with a promising future, presented here is a case report of uncontrolled diabetes with abdominal pain that showed features of inflammation in the kidneys. The patient had been previously diagnosed with maxillary sinusitis with Aspergillus niger and was receiving antibiotic treatment. The urine culture performed later was negative, and the patient was referred for 18F-fluorodeoxyglucose (18F-FDG) PET Computed Tomography (CT) to look for the focus of infection. However, as blood sugar was 500 mg/dL, 18F-FDG PET CT could not be performed. Therefore, 68Ga-FAPI PET CT was run instead after taking the patient's written informed consent. The 99mTc-dimercaptosuccinic acid scan performed on another day confirmed the presence of pyelonephritis bilaterally. In situations where FDG cannot be used because of hyperglycemia, 68Ga-FAPI PET CT scan may be considered an alternative in the detection of occult infection or inflammation, as demonstrated in this case report.

Abnormal Biologic Distribution Related to Normal Saline Among 99mTc-Dimercaptosuccinic Acid Scans.

The primary aim was to describe the incidence and causes of abnormal distribution of 99mTc-dimercaptosuccinic acid (99mTc-DMSA) among patients who underwent renal scans in Royal Hospital (Oman) in 2020. The secondary aim was to assess the effect of a specific batch of normal saline A (batch 132129) compared with another normal saline, B (batches 132589 and 133325), used in the preparation of 99mTc-DMSA on the abnormal biodistribution of 99mTc-DMSA. Methods: This was an ambidirectional cohort study that included all patients who underwent 99mTc-DMSA renal scanning between January and December 2020. Both prospective and retrospective data collection was used. The collected data included possible causes of abnormal biodistribution, quality of 99mTc-DMSA and normal saline, and time of 99mTc-DMSA injection. Results: The total incidence of abnormal biodistribution was 26.5%, with the most common cause being a high creatinine level (29%). Normal saline batch A was significantly associated with abnormal biodistribution (49.7%), compared with batch B (6.6%) (P < 0.001). This association was more prominent among patients injected with the 99mTc-DMSA preparation after 2 h (83.0%) compared with before 2 h (13.3%). Conclusion: A high incidence of abnormal biodistribution of 99mTc-DMSA was detected and-for what is the first time, to our knowledge, in the literature-a specific preservative-free, normal saline that is up to standard has been identified as a significant cause of abnormal biodistribution. Nuclear medicine professionals and pharmaceutical companies should take note of this possible cause of abnormal 99mTc-DMSA biodistribution.

Usefulness of simulation in optimizing imaging settings for pediatric technetium-99m-dimercaptosuccinic acid single-photon emission computed tomography.

Technetium-99m (99mTc) dimercaptosuccinic acid (DMSA) single-photon emission computed tomography (SPECT) has been used to diagnose renal scarring. The Japanese Society of Nuclear Medicine recently revised the 'Consensus Guidelines for Pediatric Nuclear Medicine Examination.' In this study, we compared simulation data with actual data obtained using a pediatric phantom for 99mTc-DMSA examinations and evaluated the usefulness of simulations in determining the optimal acquisition conditions for SPECT images. A SPECT quality assurance (QA) phantom study produced images with a renal-to-background 99mTc ratio of 283:1 kBq/ml. The projection data for the simulation were simulated using the simulation of imaging nuclear detectors. To compare the actual measurements and simulations, recovery factors were used for the SPECT QA phantom for image quality assessment. Defect contrast and visual evaluation using Scheffe's method of pairwise comparison were used for the pediatric kidney phantom. The optimal imaging settings using a kidney phantom required an acquisition time of more than 8 min. The maximum difference in the recovery coefficient between the simulation and actual measurement using the SPECT QA phantom was 6%. We showed that an acquisition time of more than 8 min was necessary for DMSA-SPECT. In addition, phantom simulations were approximately equivalent to the actual measurement data and the adaptability of simulations was confirmed.