Booster administration of Tc-99m PMT for delayed static imaging in patients with biliary atresia.

OBJECTIVE: Tc-99m N-pyridoxyl-5-methyl-tryptophan (PMT) hepatobiliary scintigraphy has high diagnostic performance for biliary atresia. Our hospital implements standard Tc-99m PMT administration followed by a 6 h static imaging review; booster doses are given in cases requiring 24 h delayed scans. This study aimed to evaluate the diagnostic performance of this method. METHODS: A total of 37 pediatric patients who underwent Tc-99m PMT biliary scintigraphy were classified into the surgically-diagnosed biliary atresia or non-biliary atresia groups. The absence of tracer accumulation in the small bowel was considered a hepatobiliary scintigraphic diagnosis of biliary atresia. The Clopper-Pearson method was used to calculate the 95% confidence intervals (CIs) for determining the diagnostic accuracy, negative predictive value, positive predictive value, sensitivity, and specificity of Tc-99m PMT biliary scintigraphy. RESULTS: Among the 37 patients, 12 were classified into the diagnosis of biliary atresia group. Regarding biliary scintigraphy findings, 16 of 37 patients demonstrated tracer accumulation in the small bowel within 6 h of testing. These cases were diagnosed as non-biliary atresia, requiring no further testing or booster administration. In contrast, 21 patients underwent delayed testing requiring booster administration, which revealed 13 without tracer excretion and 11 who were diagnosed with biliary atresia. Among the eight patients with tracer accumulation, only one was diagnosed with biliary atresia. Furthermore, two cases without tracer excretion and seven cases with tracer excretion were clinically diagnosed as non-biliary atresia. The diagnostic performance of our examination was as follows: a diagnostic accuracy of 91.9% (34/37; 95% CIs 78.0-98.3%), sensitivity of 91.6% (11/12; 95% CIs 61.5-99.8%), specificity of 92.0% (23/25; 95% CIs 74.0-99.0%), a positive predictive value of 84.6% (11/13; 95% CIs 54.6-98.0%), and a negative predictive value of 95.8% (23/24; 95% CIs 78.9-99.9%). CONCLUSIONS: Our protocol for Tc-99m PMT biliary scintigraphy using tracer booster administration demonstrated reliable diagnostic performance for biliary atresia. Notably, 43% of cases did not require booster administration, indicating that lesser radiation exposure may still yield comparable diagnostic accuracy.

Correction: Investigation of the new non-invasive semi-quantitative method of 123I-IMP pediatric cerebral perfusion SPECT.

[This corrects the article DOI: 10.1371/journal.pone.0241987.].

A single-center experience of using milk scintigraphy in 251 pediatric patients: A retrospective study.

To report our experience with milk gastroesophageal scintigraphy and the management of gastroesophageal reflux (GER) in children. In 251 pediatric patients we recorded age, underlying disease, central nervous system (CNS) disorders, and GER management. GER management was classified based on treatment plans: grade 0, non-pharmacological treatment; grade 1, non-pharmacological but using a nasogastric tube; grade 2, pharmacological treatment; grade 3, transpyloric feeding; and grade 4, Nissen fundoplication surgery. Patients were included in classified groups with (grades 2, 3, and 4) and without (grades 0 and 1) GER treatment. We evaluated the GER height (classified based on the height of GER, grade 0; no GER, 1; GER in the lower esophagus, 2; GER in the upper esophagus), GER duration in the lower and upper esophagus, presence or absence of massive GER amounts in the lower and upper esophagus, and gastric emptying time. We compared milk scintigraphy results and patient characteristics between groups with (grades 2, 3, and 4) and without (grades 0 and 1) GER treatment. We treated 121 patients for GER. CNS disorders (presence/absence: 46/74 with vs 21/110 without treatment, P < .001). The GER height grade (1.7 ±â€…0.5 [range, 0-2] with vs 1.5 ±â€…0.7 [range, 0-2] without treatment, P = .002), massive GER amount (present/absent: 21/99 with vs 9/122 without treatment, P = .011), and duration of GER (seconds) (324.5 ±â€…508.3 [range, 0-1800] vs 125.0 ±â€…291.9 [range, 0-1750], P < .001) in the upper esophageal half differed significantly. Similarly massive GER amount (present/absent: 54/66 with vs 34/97 without treatment, P = .002) and GER duration (621.3 ±â€…601.0 [range, 0-1800] vs 349.8 ±â€…452.4 [range, 0-1800], P < .001) in the lower esophageal half differed significantly. Additionally, CNS disorders, age, and massive GER in the upper esophageal half differed significantly among grades 2 and 4 in treated patients (P < .05, P < .001, P < .05, respectively). Milk scintigraphy is useful for deciding whether GER treatment is indicated. However, the treatment plan needs to be decided based on each patient's condition.

Incidence of renal scarring on technetium-99 m dimercaptosuccinic acid renal scintigraphy after acute pyelonephritis, acute focal bacterial nephritis, and renal abscess.

OBJECTIVE: To evaluate the association between the incidence of renal scarring on technetium-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and the severity of renal parenchymal infections, such as acute pyelonephritis (APN), acute focal bacterial nephritis (AFBN), and renal abscess, based on computed tomography (CT) diagnosis. METHODS: Sixty-one children with renal parenchymal infections were included and classified into two groups: those with (renal scarring group) and without renal scarring (non-renal scarring group) on chronic-phase DMSA renal scintigraphy. The severity of renal parenchymal infection was classified into three grades using CT: APN, AFBN, and renal abscess as grades 1, 2, and 3, respectively. The severity of renal parenchymal infection, vesicoureteral reflux (VUR) grade, and intrarenal reflux occurrence during voiding cystourethrography (VCUG) were evaluated between the renal and non-renal scarring groups. Fisher's exact test and Mann-Whitney U test were used for statistical analysis. RESULTS: Renal scars were detected in 28 (45.9%) of the 61 patients. We found that 2/9 (22.2%), 18/41 (43.9%), and 8/11 (72.7%) patients with APN (grade 1), AFBN (grade 2), and renal abscess (grade 3) had renal scarring, respectively. There was a significant difference in the grade of severity of renal parenchymal infection between the renal (median = 2 [interquartile range, 2-3]) and non-renal (median = 2 [interquartile range, 2-2]) scarring groups (p = 0.023). There was a significant difference in the grade of VUR between the renal (median = 3 [interquartile range, 0-4]) and non-renal (median = 0 [interquartile range, 0-2]) scarring groups (p = 0.004). No significant difference in intrarenal reflux occurrence was observed between the renal (present/absent: 3/25) and non-renal (present/absent: 0/29) scarring groups (p = 0.112). CONCLUSION: Our results showed that pediatric patients with renal scarring on chronic-phase DMSA renal scintigraphy tended to have a more severe renal infection.

Insufficient hepatic uptake in pediatric patients on lymphoscintigraphy.

BACKGROUND: To demonstrate the association between pediatric outcomes and tracer hepatic uptake as a marker of systemic circulation in lymphoscintigraphy. METHODS: We included 31 initial lymphoscintigraphic studies. We compared the presence or absence of hepatic uptake between deceased and survived patients in both early and delayed images using Fisher's exact test. Kaplan-Meier survival analysis was performed based on imaging results, and these curves were compared using the log-rank test. The primary endpoint was death and the survival period was defined from the day of examination to the day of the last visit or death. RESULTS: Of 31 patients, six died. Hepatic uptake was significantly different in both early and delayed images (early images, died [with/without visualization] vs. survived [with/without visualization], 0/6 vs. 13/12, P = 0.028; delayed images, died [with/without visualization] vs. survived [with/without visualization], 2/4 vs. 22/3, P = 0.014) between deceased and survived patients. Survival periods were significantly different between the two groups with and without hepatic uptake in early and delayed images (with/without visualization in early imags = 1,177.1 ± 773.8 days/426.7 ± 419.8 days, P = 0.008 and with/without visualization in delayed images = 821.3 ± 738.0 days/467.4 ± 452.4 days, P = 0.003). CONCLUSIONS: Visualization of hepatic uptake in both early and delayed lymphoscintigraphy is associated with patient outcomes. Hepatic uptake could represent tracer inflow into the systemic circulation, indicating preservation of the connection between the lymphatic system and the systemic circulation. Physicians should evaluate these findings carefully on lymphoscintigraphy.

Investigation of the new non-invasive semi-quantitative method of 123I-IMP pediatric cerebral perfusion SPECT.

In pediatric cases requiring quantification of cerebral blood flow (CBF) using 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT), arterial blood sampling is sometimes impossible due to issues such as movement, crying, or body motion. If arterial blood sampling fails, quantitative diagnostic assessment becomes impossible despite radiation exposure. We devised a new easy non-invasive microsphere (e-NIMS) method using whole-body scan data. This method can be used in conjunction with autoradiography (ARG) and can provide supportive data for invasive CBF quantification. In this study, we examined the usefulness of e-NIMS for pediatric cerebral perfusion semi-quantitative SPECT and compared it with the invasive ARG. The e-NIMS estimates cardiac output (CO) using whole-body acquisition data after 123I-IMP injection and the body surface area from calculation formula. A whole-body scan was performed 5 minutes after the 123I-IMP injection and CO was estimated by region of interest (ROI) counts measured for the whole body, lungs, and brain using the whole-body anterior image. The mean CBF (mCBF) was compared with that acquired via ARG in 115 pediatric patients with suspected cerebrovascular disorders (age 0-15 years). Although the mCBF estimated by the e-NIMS indicated a slight deviation in the extremely low- or high-mCBF cases when compared with the values acquired using the invasive ARG, there was a good correlation between the two methods (r = 0.799; p < 0.001). There were no significant differences in the mCBF values based on physical features, such as patients' height, weight, and age. Our findings suggest that 123I-IMP brain perfusion SPECT with e-NIMS is the simplest semi-quantitative method that can provide supportive data for invasive CBF quantification. This method may be useful, especially in pediatric brain perfusion SPECT, when blood sampling or identifying pulmonary arteries for CO estimation using the graph plot method is difficult.

Evaluation of the Effect of Tumor Position on Standardized Uptake Value Using Time-of-Flight Reconstruction and Point Spread Function.

OBJECTIVES: The present study was conducted to examine whether the standardized uptake value (SUV) may be affected by the spatial position of a lesion in the radial direction on positron emission tomography (PET) images, obtained via two methods based on time-of-flight (TOF) reconstruction and point spread function (PSF). METHODS: A cylinder phantom with the sphere (30 mm diameter), located in the center was used in this study. Fluorine-18 fluorodeoxyglucose (18F-FDG) concentrations of 5.3 kBq/ml and 21.2 kBq/ml were used for the background in the cylinder phantom and the central sphere respectively. By the use of TOF and PSF, SUV max and SUV mean were determined while moving the phantom in a horizontal direction (X direction) from the center of field of view (FOV: 0 mm) at 50, 100, 150 and 200 mm positions, respectively. Furthermore, we examined 41 patients (23 male, 18 female, mean age: 68±11.2 years) with lymph node tumors, who had undergone 18F-FDG PET examinations. The distance of each lymph node from FOV center was measured, based on the clinical images. RESULTS: As the distance of a lesion from the FOV center exceeded 100 mm, the value of SUV max , which was obtained with the cylinder phantom, was overestimated, while SUV mean by TOF and/or PSF was underestimated. Based on the clinical examinations, the average volume of interest was 8.5 cm3. Concomitant use of PSF increased SUV max and SUV mean by 27.9% and 2.8%, respectively. However, size of VOI and distance from the FOV center did not affect SUV max or SUV mean in clinical examinations. CONCLUSION: The reliability of SUV quantification by TOF and/or PSF decreased, when the tumor was located at a 100 mm distance (or farther) from the center of FOV. In clinical examinations, if the lymph node was located within 100 mm distance from the center of FOV, SUV remained stable within a constantly increasing range by use of both TOF and PSF. We conclude that, use of both TOF and PSF may be helpful.

Evaluation of (99m)Tc-myocardial Perfusion SPECT Attenuation Correction by Hybrid SPECT/CT-Examination by Quantitative Analysis-.

A non-uniform attenuation correction is necessary for the myocardial perfusion image (MPI) SPECT that is one of the images of the trunk. Simultaneous non-uniform attenuation correction during the process of SPECT reconstruction was enabled by developing hybrid SPECT/CT. Image acquisition of (99m)Tc MPI with hybrid SPECT/CT was performed in a phantom study and clinical cases. We evaluated the effect of non-uniform attenuation correction by Filtered Back Projection (FBP) or Ordered Subsets-Expectation Maximization (OS-EM) using visual analysis and quantitative analysis with a 17-segment model. The phantom study and the clinical cases differed somewhat as follows. In the phantom study, the count increased significantly with non-uniform attenuation correction in visual analysis and quantitative analysis. In the clinical cases, non-uniform attenuation correction increased the quantitative count in the basal and middle layer of the heart, and visual uniformity of the whole heart improved. However, the visual and quantitative count in the apex decreased with non-uniform attenuation correction. As a result, diagnostic performance for coronary heart disease is expected to be improved by this new technique using hybrid SPECT/CT.

[Examination of optimal imaging start time as determined from neighboring organ accumulation on (99m)Tc-tetrofosmin adenosine stress myocardial SPECT].

For ATP stress (99m)Tc-Tetrofosmin myocardial perfusion images (MPI), SPECT imaging is normally started 60 minutes after tracer injection. When the same procedure is applied to Adenosine (Ado) stress MPI, the frequency of the mask-out procedure after reconstruction (MOP) is increased. In this study, we examined the optimal imaging time from accumulation and distribution of isotope to neighboring organs. Time-count curves from dynamic and planer images of the heart, liver, and left upper abdomen were generated in 7 patients for optimal imaging time. MOP was evaluated in ATP stress MPI, in which imaging started 60 minutes after tracer injection (ATP 60), Ado stress MPI with imaging 60 minutes after injection (Ado 60), and Ado stress MPI with imaging 30 minutes after injection (Ado 30), in 575 patients. Up to 30 minutes after injection, washout from the liver was rapid, but after 30 minutes, it was slow. Washout from the left upper abdomen was not constant. MOP was 12.1% ATP 60, 23.1% Ado 60, and 13.2% Ado 30. Changing from Ado 60 to Ado 30 significantly decreased MOP (p<0.05). On adenosine stress MPI, it shortened examination time and enabled SPECT imaging to start 30 minutes after tracer injection.