Vesicoureteral reflux (VUR) is a common cause of urinary tract infection in children. The primary goals of managing VUR are to prevent pyelonephritis, renal damage, and long-term complications. Management may be either medical or surgical. The rationale of medical therapy is that spontaneous resolution of reflux often occurs with time. Surgical therapy is based on the principle that eliminating the reflux will minimize the likelihood of renal damage and other reflux related complications. Open ureteral reimplantation is 95~98% effective for correcting reflux, and has been the standard surgical treatment for many years. In recent years, the management of VUR has changed dramatically, mostly because of the widespread acceptance of endoscopic treatment. Optimal materials for endoscopic treatment need to be easy to inject, nontoxic, and not to migrate to other organs, result in minimal local inflammation, and be well encapsulated. Since the first clinical application of endoscopic treatment for VUR in 1984 employed subureteric polytetrafluoroethylene injection, the materials and techniques have improved considerably. Following the approval of dextranomer/hyaluronic acid by the U.S. Food and Drug Administration in 2001, the endoscopic treatment of VUR has become increasingly popular in many parts of the world. The combination of increased success, minimal morbidity, a reasonable safety profile, and short operative time has strengthened the role of endoscopic treatment for VUR. The long-term durability and reproducibility of results will make endoscopic treatment an effective alternative to antibiotic prophylaxis in low-grade reflux and to open surgery in high-grade reflux.
Antibiotic Prophylaxis ; Child ; Endoscopy ; Humans ; Inflammation ; Operative Time ; Pediatrics ; Polytetrafluoroethylene ; Pyelonephritis ; Replantation ; Reproducibility of Results ; United States Food and Drug Administration ; Ureter ; Urinary Tract Infections ; Vesico-Ureteral Reflux

The physiomic approach is now widely used in the diagnosis of cardiovascular diseases. There are two possible methods for cardiovascular physiome: the traditional mathematical model and the machine learning (ML) algorithm. ML is used in almost every area of society for various tasks formerly performed by humans. Specifically, various ML techniques in cardiovascular medicine are being developed and improved at unprecedented speed. The benefits of using ML for various tasks is that the inner working mechanism of the system does not need to be known, which can prove convenient in situations where determining the inner workings of the system can be difficult. The computation speed is also often higher than that of the traditional mathematical models. The limitations with ML are that it inherently leads to an approximation, and special care must be taken in cases where a high accuracy is required. Traditional mathematical models are, however, constructed based on underlying laws either proven or assumed. The results from the mathematical models are accurate as long as the model is. Combining the advantages of both the mathematical models and ML would increase both the accuracy and efficiency of the simulation for many problems. In this review, examples of cardiovascular physiome where approaches of mathematical modeling and ML can be combined are introduced.
Cardiovascular Diseases ; Diagnosis ; Humans ; Jurisprudence ; Machine Learning ; Models, Theoretical ; Patient-Specific Modeling

A tail-on-detector (TOD) view has been used to see the symphysis pubis or sacrococcyx in skeletal scintigraphy, but it is inconvenient to acquire because a patient must sit or lean on a detector. The TOD views are still frequently performed in training hospitals in Korea, although it is becoming almost impossible to sit on a camera in this age of dual-headed cameras. The authors show cases with lateral views obtained in supine position that were acquired for the same reason; they are easier and more useful than the TOD views.
Coccyx ; Humans ; Korea ; Radionuclide Imaging* ; Sacrococcygeal Region* ; Sacrum ; Supine Position ; Technetium Tc 99m Medronate

A 44-year-old man with a past medical history of splenectomy came to hospital because of epigastric pain. Abdominopelvic computed tomography(CT) showed a soft tissue mass and multifocal variable-sized nodules as well as findings suggestive of cholecystitis. Subsequently, he underwent Tc-99m-labeled heat-denatured red blood cell(RBC) scintigraphy to evaluate the mass and nodules. The scintigraphy confirmed multifocal peritoneal splenosis in the abdominopelvic cavity.
Adult ; Cholecystitis ; Erythrocytes* ; Humans ; Radionuclide Imaging* ; Spleen ; Splenectomy ; Splenosis*

PURPOSE: Aspiration scintigraphy is a procedure of nuclear imaging to evaluate aspiration and of quantifying the amount of aspirate. The ultimate goal of our study is to define the correlation between aspiration and aspiration pneumonia by aspiration scintigraphy, and this is a preliminary report of its trial. MATERIALS AND METHODS: Ten patients with positive findings by videofluoroscopy were selected. The patients ingested semi-solid food containing Tc-99m tin colloid 92.5 MBq (2.5 mCi) and images were acquired immediately after the ingestion and 3 hrs later. A fraction of aspiration to the ingested was calculated using an equation with a decay correction. RESULTS: Five patients were interpreted positive by aspiration scintigraphy. Four patients were positive at initial images and the fractions of aspiration were 0.11%, 0.11%, 0.81%, and 0.11%. The one patient who was shown aspirated at both images had initial 5.82% and delayed 2.26%. CONCLUSION: Aspiration scintigraphy enables us to localize the aspiration at any desired time of the test and to quantify its amount. Follow-up studies are warranted.
Colloids ; Eating ; Humans ; Pneumonia, Aspiration ; Radionuclide Imaging* ; Tin

PURPOSE: Gastric emptying scan (GES) is usually acquired up to 2 hours. Our study investigated whether a fraction of meal-retention in the stomach at 120 minutes (FR120) was predicted from the data measured for 90 minutes by using non-linear curve fitting. We aimed at saving the delayed imaging by utilizing mathematical models. MATERIALS AND METHODS: Ninety-six patients underwent GES immediately after taking a boiled egg with 74 MBq (2 mCi) Tc-99m DTPA. The patients were divided into Group I (T1/2 < or=90 min) and Group II (90 min< T1/2< or=120 min). Group I (n=51) had 21 men and 30 women, and Group II (n=45) 15 men and 30 women. There was no significant difference in age and sex between the two groups. Simple exponential, power exponential, and modified power exponential curves were acquired from the measured fraction of meal-retention at each time (0, 15, 30, 45, 60, 75, and 90 min) by non-linear curve fitting (MATLAB (R) 5.3) and another simple exponential fitting was performed on the fractions at late times (60, 75, and 90 min). A predicted FR120 was calculated from the acquired functional formulas. A correlation coefficient between the measured FR120 and the predicted FR120 was computed (MedCalc (R) 6.0). RESULTS: Correlation coefficients (r) between the measured FR120 and the predicted FR120 of each mathematical functions were as follows: simple exponential function (Group I: 0.8858, Group II: 0.5982, p< 0.0001), power exponential function (Group I: 0.8755, Group II: 0.6008, p< 0.0001), modified power exponential function (Group I: 0.8892, Group II: 0.5882, p< 0.0001), and simple exponential function at the late times (Group I: 0.9085, Group II: 0.6832, p< 0.0001). In all the fitting models, the predicted FR120 were significantly correlated with the measured FR120 in Group I but not in Group II. There was no statistically significant difference in correlation among the 4 mathematical models. CONCLUSION: In the cases with T1/2 < or=90 min, the predicted FR120 is significantly correlated with the measured FR120. Therefore, FR120 can be predicted from the data measured for 90 minutes by using non-linear curve fitting, saving the delayed imaging after 90 minutes when T1/2 < or=90 min is ascertained.
Female ; Gastric Emptying* ; Humans ; Male ; Models, Theoretical* ; Ovum ; Pentetic Acid ; Radionuclide Imaging* ; Stomach

Although complex fractionated electrogram (CFE) is known to be a target for catheter ablation of fibrillation, its physiological meaning in fibrillation wave-dynamics remains to be clarified. We evaluated the spatiotemporal relationships among the parameters of fibrillation wave-dynamics by simulation modeling. We generated maps of CFE-cycle length (CFE-CL), local dominant frequency (LDF), wave break (WB), and phase singularity (PS) of fibrillation in 2-dimensional homogeneous bidomain cardiac modeling (1,000 x 1,000 cells ten Tusscher model). We compared spatiotemporal correlations by dichotomizing each maps into 10 x 10 lattice zones. In spatial distribution, WB and PS showed excellent correlation (R = 0.963, P < 0.001). CFE-CL had weak correlations with WB (R = 0.288, P < 0.001), PS (R = 0.313, P < 0.001), and LDF (R = -0.411, P < 0.001). However, LDF did not show correlation with PS or WB. PSs were mostly distributed at the periphery of low CFE-CL area. Virtual ablation (5% of critical mass) of CFE-CL < 100 ms terminated fibrillation at 14.3 sec, and high LDF ablation (5% of critical mass) changed fibrillation to organized tachycardia, respectively. In homogeneous 2D fibrillation modeling, CFE-CL was weakly correlated with WB, PS, and LDF, spatiotemporally. PSs are mostly positioned at the periphery of low CFE-CL areas, and virtual ablation targeting low CFE-CL regions terminated fibrillation successfully.
Algorithms ; Atrial Fibrillation/*physiopathology ; Body Surface Potential Mapping ; Catheter Ablation ; *Electrocardiography ; Electrodes ; Heart Atria/physiopathology ; Humans ; *Models, Biological

We aimed to investigate the clinical value of persistent but downgraded vesicoureteral reflux (VUR) after dextranomer/hyaluronic acid (Dx/HA) injection in children. The medical records of 128 children (195 ureters) who underwent Dx/HA injections for VUR were reviewed. The incidences of pre- and post-operative febrile urinary tract infections (UTIs) were analyzed in children with or without persistent VUR on voiding cystourethrography (VCUG) 3 months postoperatively. The surgical results of VUR persistent children who underwent a single additional injection were assessed. The VUR resolved completely in 100 ureters (51.3%), was persistent in 95 ureters, and newly developed in 2 ureters. The incidence of pre/post-operative febrile UTIs were 0.35 +/- 0.39 per year and 0.07 +/- 0.32 per year in VUR resolved children (P < 0.001), and 0.76 +/- 1.18 per year and 0.20 +/- 0.61 per year in VUR persistent children (P < 0.001). A single additional Dx/HA injection (44 ureters) resolved VUR in 29 ureters (65.9%), and also reduced the VUR to grade I in 7 ureters (15.9%), II in 4 (9.1%), and III in 4 (9.1%). Even in children with persistent VUR after Dx/HA injection, the incidence of febrile UTIs decreased markedly. The VUR grade significantly decreases after single additional Dx/HA injection.
Antibiotic Prophylaxis ; Child ; Child, Preschool ; Dextrans/*therapeutic use ; Female ; Fever/complications/epidemiology ; Humans ; Hyaluronic Acid/*therapeutic use ; Incidence ; Male ; Retrospective Studies ; Treatment Outcome ; Urinary Tract Infections/complications/drug therapy/*epidemiology ; Vesico-Ureteral Reflux/*drug therapy/surgery

This study aimed to investigate pressure changes of renal pelvis and histological change of kidneys in a surgically induced sterile rabbit vesicoureteral reflux (VUR) model. Five rabbits served as a control group, 7 as the sham-operated group, and 8 served as the VUR group. Three weeks later, urodynamic studies were performed, and histological examinations evaluated degree of inflammation, fibrosis, and tubular damage in the kidneys. At a low infusion rate, renal pelvic pressure in the VUR group was stable until late filling phase and then increased slightly. At a high infusion rate, the renal pelvic pressures of the sham-operated and control groups were stable until late filling phase and then increased slightly, whereas the renal pelvic pressure in the VUR group steadily increased from mid filling phase. Focal thinning of the tubular epithelium and interstitial widening were observed in certain cortical areas of refluxing kidneys, without inflammatory cell infiltration. Obvious changes in the mean diameters of distal tubules and extracellular matrix volume fractions were observed in two highly refluxing kidneys. High pressure reflux with bladder instability may result in renal cortical changes.
Animals ; Disease Models, Animal ; Female ; Kidney/pathology/physiopathology ; Rabbits ; Urinary Bladder/pathology/physiopathology ; Urodynamics ; Vesico-Ureteral Reflux/etiology/*pathology/*physiopathology

PURPOSE: We aimed to evaluate the overall outcomes of endoscopic dextranomer/hyaluronic acid copolymer (Deflux) injection for vesicoureteral reflux (VUR) and analyze the factors predicting success. MATERIALS AND METHODS: A total 99 patients (58 males, 41 females) and 154 refluxing ureter units were treated with a endoscopic Deflux injection for VUR. At 3 months, radioisotope-voiding cystograms were performed to evaluate treatment responsiveness; success was defined as a resolving of VUR to less than grade I. We evaluated various perioperative factors such as gender, operation age, preoperative antibiotics duration, urinary tract infection, relative renal function and cortical defect, preoperative VUR grade, maximal flow rate in uroflowmetry, laterality of reflux, voiding dysfunction, constipation, orifice shape and trabeculation, injection technique, injection volume, number of punctures, and learning curve. RESULTS: The overall success rate was 62.3% (96/154) in refluxing ureter units (50.5% in patients). According to grade of VUR, the success rate was 87.5% (8/9), 82.2% (37/45), 67.8% (38/56), 33.3% (13/39), and 16.7% (1/6) in grade I, II, III, IV, and V, respectively (p=0.001). In multivariate analysis, preoperative VUR grade and mound morphology were identified as predictive factors (p<0.05). No significant surgery-related complications developed. CONCLUSIONS: Endoscopic Deflux injection for VUR was effective for grade I-III VUR, although the cure rate was low for grade IV-V. The factors predicting success were preoperative VUR grade and mound morphology.
Anti-Bacterial Agents ; Constipation ; Dextrans ; Endoscopy ; Humans ; Hyaluronic Acid ; Learning Curve ; Male ; Multivariate Analysis ; Punctures ; Ureter ; Urinary Tract Infections ; Vesico-Ureteral Reflux