Neonatal lymphatic flow disorders: central lymphatic flow disorder and isolated chylothorax, diagnosis and treatment using novel lymphatic imaging and interventions technique.

PURPOSE OF REVIEW: Neonatal lymphatic disorders (NLDs) are conditions that are relatively rare and difficult to treat. The recent development of lymphatic imaging, such as Dynamic Contrast-Enhanced MR Lymphangiography and Intranodal Lymphangiography has led to a new, better understanding of the anatomical substrate and pathophysiological mechanisms of the diseases. Consequently, this has allowed the development of new targeted therapeutic interventions as well as prognostication for this population with lymphatic flow disorders. RECENT FINDINGS: The underlying causes of all NLD is an obstruction or altered flow of the central lymphatic flow. Two types of NLD have been described: isolated neonatal chylothorax and central lymphatic flow disorder (CLFD). Isolated neonatal chylothorax can be treated successfully with oil-based contrast (lipiodol) embolization. CLFD secondary to obstruction of the thoraco-venous junction can be successfully treated with surgical thoracic duct-venous anastomosis. CLFD caused by elevated central pressure and/or thoracic duct dysplasia can be treated medically, including with new systemic therapies such as mammalian target of rapamycin inhibitors. SUMMARY: New diagnostic and interventional tools have recently allowed for classification, prognostication, and targeted interventions for neonatal patients with lymphatic flow disorders. Further research will build on these discoveries.

Successful use of transarterial radioembolization with yttrium-90 (TARE-Y90) in two children with hepatoblastoma.

Primary malignant liver tumors are rare but all require surgical resection as part of therapy with curative intent. A minority of patients have resectable tumors at diagnosis. Chemotherapy has a therapeutic role in hepatoblastoma but only one-third of patients have resectable disease at diagnosis. Two children with hepatoblastoma and suboptimal responses to initial chemotherapy received therapy with transarterial radioembolization utilizing yttrium-90 (TARE-Y90) and had significant response leading to resection and remission. The role of TARE-Y90 needs to be studied further to define its use in primary pediatric liver neoplasms.

Abnormal pulmonary lymphatic flow in patients with paediatric pulmonary lymphatic disorders: Diagnosis and treatment.

Pulmonary lymphatic disorders are characterized by the presence of the abnormal lymphatic tissues in the thoracic cavity, presenting clinically as chylothorax, chylopericardium, chyloptysis, interstitial lung disease and plastic bronchitis. These conditions include: neonatal chylothorax, cardiac and non-cardiac plastic bronchitis, non-traumatic chylothorax, post congenital cardiac surgery chylothorax and complex lymphatic malformations. Recently developed lymphatic imaging techniques, such as intranodal lymphangiography and dynamic contrast enhanced magnetic resonance lymphangiography demonstrated abnormal pulmonary lymphatic flow from thoracic duct into pulmonary parenchyma as a pathophysiological mechanism of these diseases. Novel minimally invasive lymphatic interventions, such as thoracic duct embolization, interstitial lymphatic embolization and surgical lympho-venous anastomosis, provide an effective treatment of these conditions.

Lymphatic Management in Single-Ventricle Patients.

Lymphatic complications in patients with single ventricle include plastic bronchitis, protein-losing enteropathy, and chylous pleural effusion are a source of significant morbidity and mortality with historically limited therapeutic options. Novel lymphatic imaging techniques such as intranodal lymphangiography, dynamic contrast enhanced magnetic resonance lymphangiography and liver lymphangiography have allowed visualization of the lymphatic system and discovery of the pathophysiological mechanism of these conditions. This mechanism includes the combination of 2 factors: increased lymphatic flow in patients with elevated central venous pressure and presence of the lymphatic anatomical variant that allows the lymph to flow in close proximity to the serous (pleural space in chylothorax) or mucosal (plastic bronchitis and protein losing enteropathy) surfaces. Novel minimally invasive lymphatic interventional techniques, such as thoracic duct embolization, interstitial embolization and liver lymphatic embolization have allowed the obliteration of these abnormal lymphatic networks, resulting in resolution of the symptoms. Further refinement of the imaging techniques and interventional methods have subsequently allowed better patient selection and improved long term outcome of these procedures.

Liver Lymphatic Imaging and Interventions: Resurrection of the Forgotten Knowledge.

Lymphatic imaging and interventions are gaining wider acceptance as the treatment of various lymphatic diseases. Meanwhile, the liver lymphatic system remains relatively unknown despite its physiological importance. Liver lymph has been at the center of the lymphatic research since the 19th century; however, the acquired knowledge has not been used in clinical research and treatment due to the lack of robust imaging methods. Recently introduced liver lymphangiography and interstitial embolization allow for the diagnosis and treatment of several diseases associated with the lymphatic system of the congested liver, providing additional treatment options for conditions that were considered incurable until now.

Case report: hepatobronchial lymphatic communications in single ventricle patients as a pathophysiological mechanism of plastic bronchitis: diagnosis and treatment.

BACKGROUND: Plastic bronchitis is a rare but devastating complication in single ventricle patients after Fontan completion. Recent advances in dynamic contrast-enhanced magnetic resonance lymphangiogram demonstrate the typical pathophysiological mechanism of the thoracic duct leaking lymphatic fluid towards the bronchi resulting in intraluminal casts. This has been termed abnormal pulmonary lymphatic perfusion and has been successfully treated in 94% of patients with thoracic duct occlusion. However, in some cases, this aberrant flow is not identified and therefore no intervention is available. This case report identifies a newly discovered origin of abnormal lymphatic flow from the liver to the bronchi and the treatment of these patients. CASE SUMMARY: We report two cases of plastic bronchitis in single ventricle patients with no identified abnormal lymphatic pulmonary perfusion from the thoracic duct. Both patients underwent liver lymphangiogram and demonstrated aberrant flow from the hepatic lymphatic ducts to the bronchi. These were successfully occluded, and plastic bronchitis symptoms resolved in both cases. DISCUSSION: The recent discovery of the abnormal pulmonary lymphatic perfusion from the thoracic duct to the bronchi has allowed successful treatment of 94% of single ventricle patients with plastic bronchitis. The discovery of hepatobronchial lymphatic perfusion reveals an occult aetiology of plastic bronchitis and a second target for embolization and successful treatment.

Abnormal Pulmonary Lymphatic Flow in Patients With Lymphatic Anomalies and Respiratory Compromise.

BACKGROUND: Pulmonary involvement in lymphatic anomalies (LA) is associated with significant morbidity and mortality. Dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) is capable of imaging the lymphatic system in a variety of pulmonary lymphatic disorders. RESEARCH QUESTION: The objective of this study is to describe the central lymphatic anatomy in patients with LA and pulmonary involvement on DCMRL. STUDY DESIGN AND METHODS: This prospective observational study enrolled 16 patients with LA (mean age, 17 years; range, 6-63 years; ratio of female to male patients, 9:7) with pulmonary involvement. All patients underwent DCMRL. The lymphatic system was assessed for the presence of mediastinal masses, interstitial lung disease, size and tortuosity of the thoracic duct (TD), and presence of abnormal pulmonary lymphatic flow. RESULTS: T2-weighted imaging showed the following: mediastinal soft tissue masses in 10 patients, diffuse pulmonary interstitial thickening in 13 patients, and bone involvement in 15 patients. DCMRL revealed abnormal pulmonary lymphatic flow in 14 of 16 patients. Abnormal pulmonary lymphatic flow originated from the TD in three of 14 patients, the retroperitoneum in six of 14 patients, and both the TD and retroperitoneum in four of 14 patients. In nine of 16 patients, the TD was dilated and tortuous. In two patients the TD was not identified, and in five patients it was normal. INTERPRETATION: Abnormal pulmonary lymphatic flow/perfusion from the TD or retroperitoneum into the lung parenchyma occurred in the majority of patients in this study. These findings can explain the interstitial lung disease and chylothorax resulting in deterioration of respiratory function in these patients. Future studies will determine whether mechanical cessation of this abnormal flow can improve pulmonary function and prolong survival in patients with LA. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov; No.: NCT02744027; URL: www.clinicaltrials.gov.

Postgraduate radiology training in sub-Saharan Africa: a review of current educational resources.

RATIONALE AND OBJECTIVE: Postgraduate training programs in radiology exist in several African nations. The ability of these programs to train radiologists is necessarily affected by local availability of educational resources, including clinical case volume, radiology equipment and maintenance, number of teaching faculty, and library and computer facilities. We sought to determine the current resources of a sample of African radiology education programs. MATERIALS AND METHODS: Site visits were conducted at three separate radiology training programs, one in Ghana and two in South Africa. At each site, the investigator conducted a technology census, assessed library resources, observed daily trainee activities, and interviewed trainees, faculty, and statisticians. RESULTS: African radiology trainees receive considerable training in fluoroscopy, ultrasound, and plain film radiography, but receive considerably less training in nuclear medicine, mammography, magnetic resonance imaging, and interventional radiology. A large amount of equipment in African teaching hospitals is inoperative because of lack of maintenance programs. Faculty to resident ratios in African teaching hospitals are much lower than in American hospitals. Needs of training programs vary greatly from hospital to hospital, and from country to country. CONCLUSION: Radiologists, radiology organizations, and radiology vendors from high-income nations are in a unique position to help Africa's postgraduate radiology training programs fulfill their mission of training Africa's next generation of radiologists. It is desirable that long-term commitments be made to teaching hospitals so that scarce donated resources may be put to the best possible use.

Abundance and diaspore weight in rare and common prairie grasses.

Abundance (g/m2) and diaspore weight are positively correlated in seven species of perennial grasses that occur in prairies. The rare grasses (<10.0 g/m2) have light dispersal units (0.06 to 1.76 mg); the common grasses (>10.0 g/m2) have heavy dispersal units (2.23 to 2.80 mg). This result is the first reported differentiating trait between related rare and common organisms occurring in same habitat.Three hypotheses that explain this phenomenon are compared; the third most likely holds. First, rare grasses may be rare because their small seeds are less successful in establishment than those of common grasses. Second, if the persistence of small populations is marginal, rare grasses may devote less energy (or other currency) to seed production. Third, rare grasses may be colonizers of spatially and temporally rare microsites appropriate for growth and thus have seeds adapted for longer distance dispersal than those of common grasses. This last hypothesis suggests a new pathway for the evolution of weeds.

Pediatric interventional radiology and dose-reduction techniques.

The pediatric interventional radiology community has worked diligently in recent years through education and the use of technology to incorporate numerous dose-reduction strategies. This article seeks to describe different strategies where we can significantly lower the dose to the pediatric patient undergoing a diagnostic or therapeutic image-guided procedure and, subsequently, lower the dose several fold to the staff and ourselves in the process. These strategies start with patient selection, dose awareness and monitoring, shielding, fluoroscopic techniques, and collimation. Advanced features such as cone-beam technology, dose-reduction image processing algorithms, overlay road mapping, and volumetric cross-sectional hybrid imaging are also discussed.

Intraoperative cerebral angiography in arteriovenous malformation resection in children: a single institutional experience.

OBJECT: The use of cerebral intraoperative angiography has been described in resection of arteriovenous malformations (AVMs) in adults. More recently, studies have described experiences with intraoperative angiography in a small number of children. However, data on the safety and clinical utility of intraoperative angiography in the pediatric population remains limited in comparison with available data in adults. The aim of the study was to evaluate the use of cerebral intraoperative angiography in children undergoing AVM resection. The clinical utility of intraoperative angiography and procedure-related complications were evaluated. METHODS: A retrospective review was performed for all patients undergoing cerebral AVM resection with intraoperative angiography at The Children's Hospital of Philadelphia between 2008 and 2012. Patient imaging and operative and medical notes were reviewed to evaluate for end points of the study. A total of 17 patients (8 males, 9 females) were identified, with a median age of 12.1 years (range 1.2-17.9 years) and median weight of 45.5 kg (range 12.1-78.9 kg). RESULTS: A total of 21 intraoperative angiography procedures were performed for 18 AVM resections in 17 patients. The technical success rate was 94%. In 2 cases (11%), intraoperative angiography demonstrated a residual AVM, and repeat resections were performed. In both cases, no recurrent disease was noted on postoperative follow-up. One procedure-related complication (4.8%) occurred in 1 patient who was positioned prone. Recurrence to date was noted in 2 (14%) of the 14 cases with available postoperative follow-up at 3.5 and 4.7 months following resection with intraoperative angiography. The median follow-up time from intraoperative angiography to the most recent postoperative angiography was 1.1 years (range 4.3 months to 3.8 years). CONCLUSIONS: Intraoperative angiography is an effective and safe adjunct for surgical management of cerebral AVMs in the pediatric population.

Percutaneous sclerotherapy in neonatal and infant head and neck lymphatic malformations: a single center experience.

PURPOSE: To evaluate the clinical outcomes of percutaneous sclerotherapy for congenital head and neck lymphatic malformations in our institution. MATERIALS AND METHODS: Over a 7-year period, 17 children (10 M, 7 F) mean age 5.8 months (5 days to 13 months) underwent 49 sclerotherapy procedures for congenital head and neck malformations. The imaging and clinical records were reviewed for each patient. Ten of 17 had macrocystic disease; 7 of 17 had microcystic disease. Imaging response was categorized by volume reductions of 0% to 25%, 25% to 50%, 50% to 75%, or 75% to 100%. A concentration of 10 mg/mL doxycycline was used routinely via catheter in 3 instillations with a dose range of 50 to 500 mg per session as per our standard protocol in 17 of 17 patients. In more recent patients, systemic doxycycline levels were obtained after instillations. Additional treatments included direct injection doxycycline (10/17), instillation of absolute ethanol (7/17) or sodium tetradecyl sulfate (4/17), or a combination of these methods. RESULTS: Imaging improvement of ≥ 76% was noted in 11 of 17. Of these, 8 of 11 had macrocystic disease. Four of 17 had 51% to 75% resolution, of which 3/4 were mixed. Two of 17 children had 25% to 50% resolution with a mixed lesion. Seven of 49 peri-procedural complications: hemolytic anemia in 2 infants, hypoglycemic and metabolic acidosis in 3 neonates aged 7 to 10 days, transient hypotension during absolute alcohol instillation in 1 neonate, and self-limiting skin excoriation secondary to peri-catheter leakage of doxycycline in one neonate. Neonates prone to these systemic complications had doxycycline doses of greater than 250 mg and resulted in serum levels of >5 µg/mL but as high as 21 µg/mL. Delayed neural complications occurred in 7 of 49 procedures, Horner's syndromes in 4 of 49 procedures, transient left lip weakness in 1 of 49 procedures, right facial nerve palsy in 1 of 49 procedures, and transient left hemidiaphragm paralysis in 1/49 procedures. CONCLUSION: Our experience with catheter directed doxycycline sclerotherapy provides excellent results for large macrocystic head and neck lymphatic malformations. Microcystic and mixed lesions continue to provide a therapeutic challenge.