Pediatric Lymphedema: Study of 180 Patients Referred to a Tertiary Lymphedema Clinic.

BACKGROUND: Lymphedema is due to dysfunction of the lymphatic system. It can be primary or secondary. Pediatric lymphedema is more often primary and is a chronic disease with a heavy burden on quality of life. METHODS: Medical records of patients under 18 years of age referred between 1996 and 2021 to the specialized lymphedema clinic at the Sainte-Justine University Hospital Center were reviewed. Demographic data, sex, age at presentation, location of the lymphedema, clinical features, genetic testing, symptoms, complications, investigations, and treatment were collected. RESULTS: Of 180 referred patients, lymphedema was confirmed in 151, and 137 were primary lymphedema. Median age of apparition of primary lymphedema was 7.00 years and was significantly lower in boys than in girls. Primary congenital lymphedema was more frequent in boys (51.0%, 27.3% in girls, P = .007), and onset of primary lymphedema during adolescence was more frequent in girls (53.4%, 25.0% in boys, P = .001). Lower limbs were the most impacted (88.3%). Sixty patients had genetic testing, and 38 (63.3%) of them were discovered to have a pertinent genetic mutation. The most common mutated gene was the FLT4 gene (in 9 patients). Seven patients (5.1%) had associated extensive/central lymphatic malformation and 24 (17.6%) had a polymalformative syndrome/syndromic lymphedema. CONCLUSIONS: Pediatric lymphedema is more frequent in girls, usually involves lower limb, and is most often sporadic, but often associated with a genetic mutation, and genetic testing should be performed.

Evaluation of physiological Waldeyer's ring, mediastinal blood pool, thymic, bone marrow, splenic and hepatic activity with 18F-FDG PET/CT: exploration of normal range among pediatric patients.

INTRODUCTION: While 18F-FDG PET/CT pediatrics applications have increased in number and indications, few studies have addressed normal maximum standardized uptake values (SUVmax) of referral organs in children. The purpose of this study is to assess these in a cohort of pediatric patients. MATERIAL AND METHODS: 285 18F-FDG PET/CT scans in 229 patients were reviewed. SUVmax were assessed for mediastinal blood pool (MBP), thymus (T), liver (L), spleen (S), bone marrow (BM) and Waldeyer's Ring (Wald). L/MBP and S/L ratios were calculated. Same day complete blood counts (CBC) were available for 132 studies and compared to BM and S. Means, standard deviations and correlation coefficients with age, weight and body surface area (BSA) were calculated. RESULTS: Weak correlation with age, weight or BSA was found for Wald. Strong correlations with weight/BSA more than with age were demonstrated for MBP, L and BM and moderate for S and T. After initial decrease between age 0 and 2, thymic activity peaked at age 11 years then involuted. No correlation was found between CBC ad BM or S. In 28 studies, L was less or equal to MBP. In 74 S was superior to L. CONCLUSIONS: Referral organs 18F-FDG uptake varies in children more in relation with weight and BSA than with age for key referral organs, such as L, S and MBP. In a significant number of studies, L activity may impede evaluation of treatment response in comparison with MBP or inflammation/infection evaluation in comparison with S.

Case Report 18F-FDG PET/CT of Pseudomyogenic Hemangioendothelioma.

Hemangioendotheliomas are a heterogeneous group of vascular neoplasm that may affect the liver, bone, and soft tissues. Among its variants, pseudomyogenic hemangioendothelioma is rarely encountered. Pseudomyogenic hemangioendothelioma is usually characterized by multiple soft tissue lesions, with occasional bone lesions. Fewer than 20 cases with exclusive involvement of bone structures have been reported. We describe a case of pseudomyogenic hemangioendothelioma involving multiple bony structures but without soft tissue involvement in a 7-year-old girl, imaged with F-FDG PET/CT at diagnosis and during treatment with mammalian target of rapamycin inhibitors.

18F-Flurodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) findings in children with encephalitis and comparison to conventional imaging.

PURPOSE: FDG PET/CT is emerging as a new tool for the evaluation of acute encephalitis (AE). However, to date, there are no exclusively pediatric studies on the use of FDG PET for suspected AE. The objective of this study was to compare qualitative and quantitative brain PET to conventional brain imaging in a cohort of children, and to identify patterns of metabolic abnormalities characteristic of AE. METHODS: This retrospective study included 34 children imaged with PET/CT, CT and magnetic resonance imaging (MRI). The positivity rate of all three imaging modalities was measured. Besides visual assessment, quantification of relative regional brain metabolism (RRBM) was performed and compared to a database of normal pediatric brains. RESULTS: Fourteen subjects had a clinical diagnosis of autoimmune encephalitis (AIE) or encephalitis of unknown origin (EX), six of anti-N-methyl-D-aspartate receptor (anti-NMDAr) encephalitis, three of Hashimoto's encephalopathy, three of neurolupus and eight had other subtypes of encephalitis. Quantitative PET was abnormal in 100% of cases, visually assessed PET in 94.1% of subjects, MRI in 41.2% and CT in 6.9%. RRBM quantification demonstrated multiple hyper and hypo metabolic cortical regions in 82.3% of subjects, exclusively hypermetabolic abnormalities in 3%, and exclusively hypometabolic abnormalities in 14.7%. The basal ganglia were hypermetabolic in 26.5% of cases on visual assessment and in 58.8% of subjects using quantification. CONCLUSION: In our pediatric population FDG PET was more sensitive than conventional imaging for the detection of AE, and basal ganglia hypermetabolism was frequently encountered.

Lymphoscintigraphy of Chylous Anomalies: Chylothorax, Chyloperitoneum, Chyluria, and Lymphangiomatosis-15-Year Experience in a Pediatric Setting and Review of the Literature.

In the pediatric setting, lymphoscintigraphy is used mostly for the evaluation of lymphedema. Only a few cases of chylous anomalies and lymphatic malformations imaged with lymphoscintigraphy have been reported in the literature. The aim of this study was to review the use of lymphoscintigraphy in those pathologies. Methods: All lymphoscintigraphy studies performed for chylous anomalies between 2001 and 2017 in our hospital were retrospectively reviewed. The results were correlated to clinical and radiologic findings. Lymphoscintigraphy consisted of sequential imaging after injection of 3.7-9.25 MBq (100-250 µCi) of 99mTc-filtered sulfur colloid at the level of the feet or hands. Results: Twenty-five studies were performed on 21 patients. Fourteen studies were obtained for the evaluation of chylothorax. Eleven were performed for chyloperitoneum, chyluria, chylopericardium, exudative enteropathy, or lymphangiomatosis. Ten studies were positive for lymphatic leakage, and 1 had uncertain results. After correlation with radiologic findings and follow-up, there were 7 true-negative and 5 false-negative results (previous 67Ga-interfering activity in 1, injection in only the hands in 3, and a low-fat diet in 1). One study became positive after injection in the feet, and another became positive after a switch to a high-fat diet. Conclusion: Lymphoscintigraphy is a useful tool for imaging lymphatic anomalies in children. Suggestions to optimize results include placing the patient on a high-fat diet, withholding octreotide, injecting the 4 extremities, and imaging with SPECT/CT.

Modeling the Effects of Age and Sex on Normal Pediatric Brain Metabolism Using 18F-FDG PET/CT.

Reference databases of pediatric brain metabolism are uncommon, because local brain metabolism evolves significantly with age throughout childhood, limiting their clinical applicability. The aim of this study was to develop mathematic models of regional relative brain metabolism using pediatric 18F-FDG PET with CT data of normal pediatric brains, accounting for sex and age. Methods: PET/CT brain acquisitions were obtained from 88 neurologically normal subjects, aged 6 mo to 18 y. Subjects were assigned to either a development group (n = 59) or a validation group (n = 29). For each subject, commercially available software was used to quantify the relative metabolism of 47 separate brain regions using whole-brain-normalized (WBN) and pons-normalized (PN) activity. The effects of age on regional relative brain metabolism were modeled using multiple linear and nonlinear mathematic equations, and the significance of sex was assessed using the Student t test. Optimal models were selected using the Akaike information criterion. Mean predicted values and 95% prediction intervals were derived for all regions. Model predictions were compared with the validation dataset, and mean predicted error was calculated for all regions using both WBN and PN models. Results: As a function of age, optimal models of regional relative brain metabolism were linear for 9 regions, quadratic for 13, cubic for 6, logarithmic for 12, power law for 7, and modified power law for 2 using WBN data and were linear for 9, quadratic for 25, cubic for 2, logarithmic for 6, and power law for 4 using PN data. Sex differences were found to be statistically significant only in the posterior cingulate cortex for the WBN data. Comparing our models with the validation group resulted in 94.3% of regions falling within the 95% prediction interval for WBN and 94.1% for PN. For all brain regions in the validation group, the error in prediction was 3% ± 0.96% using WBN data and 4.72% ± 1.25% when compared with the PN data (P < 0.0001). Conclusion: Pediatric brain metabolism is a complex function of age and sex. We have developed mathematic models of brain activity that allow for accurate prediction of regional pediatric brain metabolism.

Imaging of Acquired Demyelinating Syndrome With 18F-FDG PET/CT.

Acquired demyelinating syndromes include acute disseminated encephalomyelitis, transverse myelitis and may progress to multiple sclerosis (MS). Acute disseminated encephalomyelitis is characterized by impairment of level of consciousness and multifocal neurological deficits and transverse myelitis by back pain, weakness and sphincter dysfunction. Only a few cases of acquired demyelinating syndrome have been imaged with F-FDG PET/CT. We present two such cases.

H Syndrome: A Rare Genodermatosis Imaged With 18F-FDG PET/CT.

H syndrome (OMIM 612391) is an extremely rare autosomal recessive genodermatosis, characterized by extensive skin infiltration. We report a case imaged with F-FDG PET/CT.

False Negative 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Primary B-cell Lymphoma of the Bone.

We present a case of a 15-year-old male with primary bone lymphoma who was initially referred for suspicion of chronic osteomyelitis of the mandible. A bone scan and gallium scan demonstrated congruent uptake in the mandible, suggestive of chronic osteomyelitis. A biopsy subsequently showed B-cell lymphoma of the bone with low Ki-67. A fluorodeoxyglucose positron emission tomography (FDG-PET) scan performed before therapy for staging revealed no increased uptake in the mandible. This case shows an atypical presentation of a rare disorder and is presented to emphasize the importance of baseline FDG-PET.

18F-FDG-PET/CT Imaging of Thoracic and Extrathoracic Tuberculosis in Children.

Tuberculosis (TB) remains a major health problem, affecting approximately one-third of the world׳s population. The tubercle bacillus can affect virtually any organ of the human body and if left untreated can lead to severe morbidity and death. Diagnosis of active TB is challenging, especially in children. As a "great imitator," the disease can mimic numerous other pathologies, both clinically and at imaging. Although recognition of active TB is crucial to initiate adequate treatment in a timely fashion, thereby preventing transmission of disease, differentiation of active and quiescent disease is not always straightforward. Since the first reports more than 20 years ago, FDG-PET/CT imaging has been shown to detect active disease with accuracy equal or superior to other conventional imaging modalities. The role of FDG-PET in evaluating patients with TB is rapidly expanding. FDG-PET/CT can effectively identify foci of intrathoracic and extrathoracic TB, assess disease activity, differentiate between active and latent disease, monitor response to therapy, identify potential biopsy targets, and serve as a surrogate end point for new drug trials. Efficacy of FDG-PET/CT in the especially challenging pediatric population will be the focus of this review.

Timing of Hormone Withdrawal in Children Undergoing 131I Whole-Body Scans for Thyroid Cancer.

BACKGROUND: Little objective pediatric data exist to guide the optimal time needed to achieve thyroid-stimulating hormone (TSH) levels ≥30 µIU/mL prior to performing 131I or 123I whole-body scan (WBS) imaging in children with thyroid cancer in the post-thyroidectomy period or after hormone discontinuation. METHODS: Retrospective study of patients aged 5-19 years who underwent WBS. Patient data collection included type and duration of withdrawal (liothyronine [L-T3], levothyroxine [L-T4], or post-thyroidectomy status without hormonal replacement) and TSH measured prior to WBS (level and timing). RESULTS: A total of 175 TSH level measurements were performed in 68 patients. Thirty-five TSH values were obtained 2-7 weeks postoperatively and 101 values were obtained 2-8 weeks post L-T4 withdrawal. One patient in each group had a TSH level <30 µIU/mL. There was no difference in TSH levels between 3 weeks and 4 weeks postoperatively (p = 0.14) or post L-T4 cessation (p = 0.21). Thirty-nine TSH measurements were obtained 1-28 days post L-T3 withdrawal. Three patients had to be rescheduled due to inadequate TSH levels, including one after 14 days L-T3 withdrawal. CONCLUSION: TSH levels ≥30 µIU/mL were achieved at 3 weeks post thyroidectomy or after L-T4 withdrawal and after at least 2 weeks following L-T3 cessation.

Imaging Pediatric Plasmacytoid Dendritic Cell Neoplasm With FDG PET/CT: Atypical Presentation of a Rare Disease.

Blastic plasmacytoid dendritic cell neoplasm is a rare malignancy characterized by cutaneous involvement and hematological dissemination. Most affected patients are older, usually in the sixth or seventh decade of life, and this condition has rarely been described in the pediatric population. This report presents the case of a 9-year-old boy with blastic plasmacytoid dendritic cell neoplasm and demonstrates the utility of FDG PET/CT for staging and treatment follow-up.

A transdisciplinary approach to the decision-making process in extreme prematurity.

BACKGROUND: A wide range of dilemmas encountered in the health domain can be addressed more efficiently by a transdisciplinary approach. The complex context of extreme prematurity, which is raising important challenges for caregivers and parents, warrants such an approach. METHODS: In the present work, experts from various disciplinary fields, namely biomedical, epidemiology, psychology, ethics, and law, were enrolled to participate in a reflection. Gathering a group of experts could be very demanding, both in terms of time and resources, so we created a web-based discussion forum to facilitate the exchanges. The participants were mandated to solve two questions: "Which parameters should be considered before delivering survival care to a premature baby born at the threshold of viability?" and "Would it be acceptable to give different information to parents according to the sex of the baby considering that outcome differences exist between sexes?" RESULTS: The discussion forum was performed over a period of nine months and went through three phases: unidisciplinary, interdisciplinary and transdisciplinary, which required extensive discussions and the preparation of several written reports. Those steps were successfully achieved and the participants finally developed a consensual point of view regarding the initial questions. This discussion board also led to a concrete knowledge product, the publication of the popularized results as an electronic book. CONCLUSIONS: We propose, with our transdisciplinary analysis, a relevant and innovative complement to existing guidelines regarding the decision-making process for premature infants born at the threshold of viability, with an emphasis on the respective responsabilities of the caregivers and the parents.

A high prevalence of dual thyroid ectopy in congenital hypothyroidism: evidence for insufficient signaling gradients during embryonic thyroid migration or for the polyclonal nature of the thyroid gland?

BACKGROUND: Thyroid ectopy results from the failure of the thyroid precursor cells to migrate from the primordial pharynx to the anterior part of the neck. Most ectopic thyroids are revealed by congenital hypothyroidism and present as a single round mass at the base of the tongue, with no other thyroid tissue. However, some cases have dual ectopy, with part of the tissue having partially migrated. We hypothesized that this occurs more frequently than previously reported. METHODS: To determine the prevalence of dual ectopy, we reviewed the pertechnetate scintigraphies of 81 patients with congenital hypothyroidism from thyroid ectopy diagnosed between 2002 and 2011 at our institution. RESULTS: We report a series of seven cases (9%) of dual ectopy, representing an incidence ranging from 1:50,000 to 1:70,000. CONCLUSIONS: Almost one in 10 cases with congenital hypothyroidism due to thyroid ectopy has dual ectopy. This suggests that two populations of cells diverged at an early stage of development, which may arise from insufficient signaling gradients in surrounding tissues during early organogenesis or may indirectly support the polyclonal nature of the thyroid.

Right ventricle myocardial perfusion scintigraphy: feasibility and expected values in children.

Stress myocardial perfusion scintigraphy imaging (SMPSI) has important applications for evaluating coronary disease and ventricular function. Studies consistently focus on the left ventricle (LV), with no normal right ventricle (RV) data available. This study sought to evaluate the feasibility of RV perfusion with technetium (Tc-99m) sestamibi using a low radiotracer dose for children free of coronary artery (CA) anomalies and to determine its normal pattern. Patients with a history of Kawasaki disease who showed no coronary complications on selective angiography or no LV perfusion defects on SMPSI were studied at rest and during an exercise challenge. The RV uptake counts were compared with those for different segments of the LV, and multiple ratios of the uptakes between RV and LV segments were calculated. The study subjects were 23 children (age, 11.1 ± 3.3 years) imaged with 0.12 ± 0.03 mCi/kg at rest and 0.31 ± 0.06 mCi/kg during stress. The RV to LV uptake proportion was approximately 6%. Exercise-related uptake increased threefold in both the RV and the LV. The findings showed RV myocardial scintigraphy to be feasible with reproducible ratios. Potential clinical applications include acquired and congenital CA anomalies such as Kawasaki disease, right CA ostium stenosis after a switch operation, and anomalous origin of the right CA.

Differential pulmonary perfusion scan after percutaneous occlusion of the patent ductus arteriosus: one-decade consecutive longitudinal study from a single institution.

Reduced left lung perfusion has been described following percutaneous occlusion of the patent ductus arteriosus (PDA). We aimed to identify the incidence of lung perfusion abnormalities and the associated risk factors in our consecutive series. Between November 1994 and December 2003, 150 procedures were performed on 145 patients, age 4.6 +/- 4 years. Gianturco coil was used in 88.2%, Amplatzer duct occluder in 6.7%, and Rashkind Umbrella in 5.5%. Lung perfusion scan was scheduled within 48 h (LPS-1), at 6-12 months (LPS-2) and later (LPS-3) in the case of persistent abnormalities. Left lung perfusion <40% was considered abnormal. LPS-1 was obtained in 95.8% and was abnormal in 31%. LPS-2, available in 48.2%, returned to normal in 65.7% (p < 0.001). LPS-3, required in 6.2%, was normal in 55.6% (p = 0.07). Identifiable risk factors were low age and height (p < 0.01), higher Q(p)/Q(s) ratio (p < 0.05), and larger PDA size indexed for height (p < 0.001) or body surface area (p < 0.01). The number of coils or loops deployed in the pulmonary end of the PDA did not influence lung perfusion. In conclusion, we describe a high incidence of left lung perfusion reduction following percutaneous PDA occlusion, more likely in the young with large PDA. However, spontaneous recovery usually occurs within a few months.