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Currently, the prevention of recurrent immediate hypersensitivity reactions (HSRs) to contrast media (CM) requests premedication and changing the culprit contrast agent. However, strategies for the prevention of immediate HSRs to gadolinium-based magnetic resonance contrast agents (GBCAs) have not yet been established. This study aimed to evaluate the effectiveness of changing the contrast agent and single-dose premedication for HSR recurrence prevention in patients with a history of mild immediate HSR to GBCA.The outcomes of patients with mild immediate HSR to GBCA who subsequently underwent enhanced magnetic resonance imaging between October 2012 and July 2017 were analyzed. The institutional CM monitoring system was retrospectively reviewed, and data on the application of premedication and choice of CM were obtained. Gadolinium-based magnetic resonance contrast agents were classified into 3 classes according to their molecular structure (macrocyclic ionic, macrocyclic nonionic, and linear ionic). Intravenous chlorpheniramine 4 mg, 30 minutes before the GBCA administration, or intravenous methylprednisolone sodium succinate 40 mg plus chlorpheniramine 4 mg, 1 hour before the GBCA administration, was administrated as premedication regimen. Recurrence rates of immediate HSR were compared according to prevention strategies.A total of 185 patients with a history of mild immediate HSR to GBCA were re-exposed to GBCA 397 times during the study period. The overall recurrence rate was 19.6% (78/397). Changing the culprit GBCA significantly reduced the recurrence rate, compared with reusing the culprit GBCA (6.9%, 9/130 and 25.8%, 69/267; P0.001). The recurrence rate was lowest when the GBCA was changed to a different molecular structure class from the culprit agent, followed by changing to CM with the same molecular structure and reusing the culprit GBCA (6.2%, 7/113 vs 11.8%, 2/17 vs 25.8%, 69/267; P0.001 with χ test for trend). Single-dose premedication demonstrated no significant prophylactic effect on recurrence (20.4%, 17/98 vs 17.3%, 61/299 with and without premedication, respectively; P = 0.509). Premedication in addition to changing CM also showed no additional prophylactic effect (7.2%, 7/97 and 6.1%, 2/33, respectively; P = 0.821).Changing the CM from the culprit agent could reduce the chance of HSR recurrence in patients with prior mild immediate HSR to GBCA, especially when the CM was changed to one of a different molecular structure class. However, single-dose premedication administration did not show significant HSR recurrence rate difference.

The aim of this study was to identify the signal intensity (SI) changes in the dentate nucleus (DN) and the globus pallidus (GP) on unenhanced T1-weighted magnetic resonance (MR) images after multiple administration of gadolinium-based contrast agents (GBCAs) in children and compare those changes between linear and macrocyclic GBCAs.This retrospective study was approved by the institutional review board and the requirement for informed consent was waived. We identified 92 children who underwent at least 4 consecutive MR examinations exclusively using either linear GBCA (gadodiamide or gadopentetate dimeglumine, n = 41) or macrocyclic GBCA (gadoterate meglumine, n = 51). Signal intensity ratio changes in the DN to pons and GP to thalamus between the first and last MR examinations were calculated.The SI ratios in the linear group increased significantly between the first and last MR examinations (mean difference: DN to pons, 0.0461 ± 0.0480, P0.001; GP to thalamus, 0.0332 ± 0.0385, P0.001), but not in the macrocyclic group (mean difference: DN to pons, -0.0010 ± 0.0371, P = 0.855; GP to thalamus, 0.0007 ± 0.0294, P = 0.867). In the linear regression analysis, the numbers of administrations of gadodiamide and gadopentetate dimeglumine were highly associated with the differences in SI ratios (DN to pons, P0.001 and P = 0.003; GP to thalamus, P0.001 and P = 0.002, respectively).The SIs of the DN and GP on unenhanced T1-weighted images increased after serial administrations of linear GBCA, but not macrocyclic GBCA, in children. The number of linear GBCA administration had a linear association with the SI changes in the DN and GP.

The properties of brain tissue undergo dynamic changes during maturation. T1 relaxation time (T1), T2 relaxation time (T2), and proton density (PD) are now simultaneously quantifiable within a clinically acceptable time, using a synthetic magnetic resonance imaging (MRI) sequence. This study aimed to provide age-specific reference values for T1, T2, and PD in children, using synthetic MRI.We included 89 children (median age, 18 months; range, 34 weeks of gestational age to 17 years) who underwent quantitative MRI, using a multidynamic, multiecho sequence on 3 T MRI, between December 2015 and November 2016, and had no abnormal MRI/neurologic assessment findings. T1, T2, and PD were simultaneously measured in each of the 22 defined white matter and gray matter regions of interest. The measured values were plotted against age, and a curve fitting model that best explained the age dependence of tissue values was identified. Age-specific regional tissue values were calculated using a fit equation.The tissue values of all brain regions, except cortical PD, decreased with increasing age, and the robust negative association was best explained by modified biexponential model of the form Tissue values = T1 × exp (-C1 × age) + T2 × exp (-C2 × age). The quality of fit to the modified biexponential model was high in white matter and deep gray matter (white matter, R = 97%-99% [T1], 88%-95% [T2], 88%-97% [PD]; deep gray matter, R = 96%-97% [T1], 96% [T2], 49%-88% [PD]; cortex, 70%-83% [T1], 87%-90% [T2], 5%-27% [PD]). The white matter and deep gray matter changed the most dynamically within the first year of life.Our study provides age-specific regional reference values, from the neonate to adolescent, of T1, T2, and PD, which could be objective tools for assessment of normal/abnormal brain development using synthetic MRI.

This study examined the safety and usefulness of minimally invasive surgery (MIS) for malignant abdominal tumors in pediatric patients and analyzed the factors affecting the resection margin, operative time, and hospital stay of neuroblastoma (NBL) patients.We retrospectively reviewed data of pediatric patients who underwent MIS for malignant abdominal tumors from January 2011 to June 2017 at the Seoul National University Children's Hospital. Sex; age at operation; diagnosis; tumor location; operation-related data, such as operation time and transfusion; and follow-up data were reviewed. We divided patients into an excision group and a biopsy group. Detailed pathologic data were reviewed to analyze factors affecting the resection margin of NBL. Median value and range were calculated for all continuous variables. Mann-Whitney test and χ test were used as appropriate. P values of 2 years. There were no clinical factors influencing operative time or hospital stay.MIS was feasible and safe in pediatric patients with malignant abdominal tumors. R0 resection of NBL was related to age and stage.

Few studies on gastric tube interposition for esophageal reconstruction in children have assessed the long-term outcomes and quality of life (QoL). The aim of this study is to evaluate the long-term outcomes and QoL after a gastric tube interposition by reviewing our experiences with esophageal reconstruction. Twenty-six patients were included who underwent gastric tube interposition from 1996 to 2011 at our institution. We reviewed the medical records and conducted telephone surveys, prospectively performed esophagography, endoscopy, 24-hour pH monitoring, and esophageal manometry. The median follow-up period of 12 (range, 3–18) years. Median age at the time of surgery and survey were 9 (range, 2–50) months and 12.4 (range, 3.1–19.0) years, respectively. There were 14 cases of reoperation of gross type C and B esophageal atresia (EA) and 10 cases of long gap pure EA. The z scores of anthropometric data at the survey did not increase after the operation. Severe stricture in esophagography was observed in 20% of patients, but improved with balloon dilation with intact passage. Gastroesophageal reflux was able to be treated with medications. Esophageal peristalsis was observed in 1 of 8 patients in manometry. No Barrett esophagus or metaplasia was not found from endoscopy. QoL was similar to the general population and did not differ between age groups. Gastric tube interposition could be considered for esophageal reconstruction in pediatric patients when native esophageal anastomosis is impossible. Nutritional evaluation and support with consecutive radiological evaluation to assess the anastomosis site stricture are advised.

To assess the diagnostic value of arterial, pancreatic, and hepatic phase imaging with multidetector-row computed tomography of a bile duct malignancy.Our institutional review board approved this retrospective study and waived the requirement for informed consent. Forty-two patients with surgically proven hilar or extrahepatic cholangiocarcinoma, who underwent preoperative imaging with triple-phasic multidetector-row computed tomography, were included in this study. Images obtained during each phase were reviewed by 2 independent observers who assessed the tumor conspicuity and the biliary extent of the tumor and vascular invasion by the tumor. For quantitative analysis, another radiologist measured the tumor attenuation, the normal liver parenchyma, the aorta, and the main portal vein on each phase image.The degree of tumor conspicuity was higher in the pancreatic and hepatic phases than in the arterial phase (P0.01); however, there was no statistical difference in tumor conspicuity between the pancreatic and hepatic phases (P0.05). The mean tumor attenuation was greater in the hepatic phase at 114.2 +/- 24.6 Hounsfield units versus 72.9 +/- 18.3 Hounsfield units in the arterial phase (P0.001). The images obtained in the hepatic phases were significantly superior to those obtained in the arterial phase for predicting the tumor involvement into the secondary biliary confluence (P0.05). In predicting for the vascular involvement by the tumors, there was no significant difference among the 3 enhancement phases (P0.05).Routine acquisition of arterial phase images is not necessary for successful detection and evaluation of the extent of hilar or extrahepatic bile duct carcinoma.