Ramon Sanchez

Use of Medical Imaging Procedures With Ionizing Radiation in Children: A Population-Based Study

OBJECTIVE To determine population-based rates of the use of diagnostic imaging procedures with ionizing radiation in children, stratified by age and sex. DESIGN Retrospective cohort analysis. SETTING All settings using imaging procedures with ionizing radiation. PATIENTS Individuals younger than 18 years, alive, and continuously enrolled in UnitedHealthcare between January 1, 2005, and December 31, 2007, in 5 large US health care markets. MAIN OUTCOME MEASURES Number and type of diagnostic imaging procedures using ionizing radiation in children. RESULTS A total of 355 088 children were identified; 436 711 imaging procedures using ionizing radiation were performed in 150 930 patients (42.5%). The highest rates of use were in children older than 10 years, with frequent use in infants younger than 2 years as well. Plain radiography accounted for 84.7% of imaging procedures performed. Computed tomographic scans-associated with substantially higher doses of radiation-were commonly used, accounting for 11.9% of all procedures during the study period. Overall, 7.9% of children received at least 1 computed tomographic scan and 3.5% received 2 or more, with computed tomographic scans of the head being the most frequent. CONCLUSIONS Exposure to ionizing radiation from medical diagnostic imaging procedures may occur frequently among children. Efforts to optimize and ensure appropriate use of these procedures in the pediatric population should be encouraged.

ICRP publication 121: radiological protection in paediatric diagnostic and interventional radiology.

Paediatric patients have a higher average risk of developing cancer compared with adults receiving the same dose. The longer life expectancy in children allows more time for any harmful effects of radiation to manifest, and developing organs and tissues are more sensitive to the effects of radiation. This publication aims to provide guiding principles of radiological protection for referring clinicians and clinical staff performing diagnostic imaging and interventional procedures for paediatric patients. It begins with a brief description of the basic concepts of radiological protection, followed by the general aspects of radiological protection, including principles of justification and optimisation. Guidelines and suggestions for radiological protection in specific modalities - radiography and fluoroscopy, interventional radiology, and computed tomography - are subsequently covered in depth. The report concludes with a summary and recommendations. The importance of rigorous justification of radiological procedures is emphasised for every procedure involving ionising radiation, and the use of imaging modalities that are non-ionising should always be considered. The basic aim of optimisation of radiological protection is to adjust imaging parameters and institute protective measures such that the required image is obtained with the lowest possible dose of radiation, and that net benefit is maximised to maintain sufficient quality for diagnostic interpretation. Special consideration should be given to the availability of dose reduction measures when purchasing new imaging equipment for paediatric use. One of the unique aspects of paediatric imaging is with regards to the wide range in patient size (and weight), therefore requiring special attention to optimisation and modification of equipment, technique, and imaging parameters. Examples of good radiographic and fluoroscopic technique include attention to patient positioning, field size and adequate collimation, use of protective shielding, optimisation of exposure factors, use of pulsed fluoroscopy, limiting fluoroscopy time, etc. Major paediatric interventional procedures should be performed by experienced paediatric interventional operators, and a second, specific level of training in radiological protection is desirable (in some countries, this is mandatory). For computed tomography, dose reduction should be optimised by the adjustment of scan parameters (such as mA, kVp, and pitch) according to patient weight or age, region scanned, and study indication (e.g. images with greater noise should be accepted if they are of sufficient diagnostic quality). Other strategies include restricting multiphase examination protocols, avoiding overlapping of scan regions, and only scanning the area in question. Up-to-date dose reduction technology such as tube current modulation, organ-based dose modulation, auto kV technology, and iterative reconstruction should be utilised when appropriate. It is anticipated that this publication will assist institutions in encouraging the standardisation of procedures, and that it may help increase awareness and ultimately improve practices for the benefit of patients.

A critical evaluation of US for the diagnosis of pediatric acute appendicitis in a real-life setting: how can we improve the diagnostic value of sonography?

BackgroundWe have observed that day-to-day use of US for acute appendicitis does not perform as well as described in the literature.ObjectiveReview the diagnostic performance of US in acute appendicitis with attention to factors that influence performance.Materials and methodsRetrospective review of all sonograms for acute appendicitis in children from May 2005 to May 2010 with attention to the rate of identification of the appendix, training of personnel involved and diagnostic accuracy.ResultsThe appendix was identified in 246/1,009 cases (24.4%), with identification increasing over time. The accuracy of US was 85–91% with 35 false-positives and 54 false-negatives. Pediatric sonographers were significantly better at identifying the appendix than non-pediatric sonographers (P < 0.0001). Increased weight was the only patient factor that influenced identification of the appendix (P = 0.006). CT use was stable over the 5 years but declined in cases where the appendix was identified by US.ConclusionIn day-to-day use, US does not perform as purported in the literature. We do not visualize the appendix as often as we should and false-negative and false-positive exams are too common. To improve the diagnostic performance of this modality, involvement by experienced personnel and/or additional training is needed.

Reevaluating the sonographic criteria for acute appendicitis in children: a review of the literature and a retrospective analysis of 246 cases.

RATIONALE AND OBJECTIVES There has been little rigorous evaluation of the sonographic criteria for acute appendicitis in children. Our clinical experience has called the traditional diagnostic criteria into question. We set out to review the literature, evaluate the most commonly applied diagnostic criteria for acute appendicitis, and identify those criteria that best predict the presence of disease. MATERIALS AND METHODS A critical review of the literature concerning the sonographic diagnosis of acute appendicitis was performed. Based on diagnostic criteria identified in that review, two independent, blinded pediatric radiologists retrospectively reviewed 246 right lower quadrant ultrasound examinations in which the appendix was identified with attention to commonly described diagnostic criteria for acute appendicitis. Multivariate and classification and regression tree analysis were performed to identify criteria that predict appendicitis. RESULTS In a multivariate analysis, inflammation of the periappendiceal fat is the only finding that statistically significantly predicts acute appendicitis (OR = 68.93, P < .0001). Other criteria such as diameter, noncompressibility, hyperemia, the presence of an appendicolith, and loss of stratification of the appendiceal wall do not independently predict appendicitis. CONCLUSION Periappendiceal fat infiltration is the most important diagnostic criterion for acute appendicitis in children. Strict application of other criteria such as diameter should be avoided.

Expanding upon the Unilateral Hyperlucent Hemithorax in Children

Unilateral hyperlucent hemithorax is a common pediatric chest radiographic finding that may also be seen at computed tomography. It may result from congenital or acquired conditions involving the pulmonary parenchyma, airway, pulmonary vasculature, pleural space, and chest wall, as well as from technical factors such as patient rotation. Unilateral hyperlucent hemithorax has a broad differential diagnosis that includes unilateral emphysematous or bullous disease, pneumatocele, foreign body aspiration, Swyer-James syndrome, congenital lobar emphysema, endobronchial mass, unilateral pulmonary agenesis, proximal interruption of the pulmonary artery, scimitar syndrome, diaphragmatic hernia, and Poland syndrome. Although certain causes of unilateral hyperlucent hemithorax are clinically significant and potentially life threatening, others are of minimal or no clinical significance. When evaluating a patient with this finding, it is important to establish whether the apparent unilateral hyperlucent hemithorax is truly too lucent (hypoattenuating) or if the contralateral hemithorax is too opaque (hyperattenuating). It is imperative that radiologists be aware of the various causes of unilateral hyperlucent hemithorax so that they may diagnose the underlying condition and appropriately guide patient management.

Mesenteric pseudoaneurysm and cerebral stroke as sequelae of infective endocarditis in an adolescent

Infective endocarditis is uncommon in children, and there is a paucity of literature concerning cases that involve unique or resistant organisms. Complications associated with infective endocarditis are distinctly rare and poorly characterized, especially unusual sequelae such as pseudoaneurysm of the abdominal mesentery. Our case involves an adolescent who presented with several weeks of fever and eventual cardiac murmur and was found to have vancomycin-resistant Enterococcus growing as a vegetation on a previously undiagnosed bicuspid aortic valve. He had a cerebral stroke presenting as Brocas aphasia before cardiac surgery, as well as a superior mesenteric artery pseudoaneurysm several days postoperatively. The case highlights some of the serious surgical complications that can occur in young persons with infective endocarditis, as well as many of the problems involved in managing a patient with highly resistant pathogens and a surgically challenging location of the aneurysm.

Small Bowel Diameter in Short Bowel Syndrome as a Predictive Factor for Achieving Enteral Autonomy

Children with short bowel syndrome commonly have dilated small bowel. We found that the extent of dilation was associated with bowel length and that both were related to achieving enteral autonomy.

Prospective cohort study of ultrasound-ultrasound and ultrasound-MR enterography agreement in the evaluation of pediatric small bowel Crohn disease

BackgroundThere is a paucity of published literature describing ultrasound (US)-US and US-MR enterography (MRE) inter-radiologist agreement in pediatric small bowel Crohn disease.ObjectiveTo prospectively assess US-US and US-MRE inter-radiologist agreement in pediatric small bowel Crohn disease.Materials and methodsInstitutional Review Board approval and informed consent/assent were obtained for this HIPAA-compliant prospective cohort study of children with newly diagnosed distal small bowel Crohn disease (July 2012 to December 2014). Enrolled subjects (n = 29) underwent two small bowel US examinations performed by blinded independent radiologists both before and at multiple time points after initiation of medical therapy (231 unique US examinations, in total); 134 US examinations were associated with concurrent MRE. The MRE examination was interpreted by a third blinded radiologist. The following was documented on each examination: involved length of ileum (cm); maximum bowel wall thickness (mm); amount of bowel wall and mesenteric Doppler signal, and presence of stricture, penetrating disease and/or abscess. Inter-radiologist agreement was assessed with single-measure, three-way, mixed-model intra-class correlation coefficients (ICC) and prevalence-adjusted, bias-adjusted kappa statistics (κ). Numbers in brackets are 95% confidence intervals.ResultsUltrasound-US agreement was moderate for involved length (ICC: 0.41 [0.35-0.49]); substantial for maximum bowel wall thickness (ICC: 0.67 [0.64-0.70]); moderate for bowel wall Doppler signal (ICC: 0.53 [0.48-0.59]); slight for mesenteric Doppler signal (ICC: 0.25 [0.18-0.42]), and moderate to almost perfect for stricture (κ: 0.54), penetrating disease (κ: 0.80), and abscess (κ: 0.96). US-MRE agreement was moderate for involved length (ICC: 0.42 [0.37-0.49]); substantial for maximum bowel wall thickness (ICC: 0.66 [0.65-0.69]), and substantial to almost perfect for stricture (κ: 0.61), penetrating disease (κ: 0.72) and abscess (κ: 0.88).ConclusionUltrasound-US agreement was similar to US-MRE agreement for assessing pediatric small bowel Crohn disease. Discrepancies in US-US and US-MRE reporting question the utility of US as an accurate, reproducible radiologic biomarker for assessing response to medical therapy and disease-related complications.

Pediatric Small Bowel Crohn Disease: Correlation of US and MR Enterography

Small bowel Crohn disease is commonly diagnosed during the pediatric period, and recent investigations show that its incidence is increasing in this age group. Diagnosis and follow-up of this condition are commonly based on a combination of patient history and physical examination, disease activity surveys, laboratory assessment, and endoscopy with biopsy, but imaging also plays a central role. Ultrasonography (US) is an underutilized well-tolerated imaging modality for screening and follow-up of small bowel Crohn disease in children and adolescents. US has numerous advantages over computed tomographic (CT) enterography and magnetic resonance (MR) enterography, including low cost and no required use of oral or intravenous contrast material. US also has the potential to provide images with higher spatial resolution than those obtained at CT enterography and MR enterography, allows faster examination than does MR enterography, does not involve ionizing radiation, and does not require sedation or general anesthesia. US accurately depicts small bowel and mesenteric changes related to pediatric Crohn disease, and US findings show a high correlation with MR imaging findings in this patient population.

Wandering spleen causing gastric outlet obstruction and pancreatitis.

Excessive splenic mobility (i.e. wandering spleen) is a rare condition caused by laxity or deficiency of all the spleen’s normal ligamentous attachments in the left hypochondrium. In the pediatric population, a wandering spleen may present as an incidental finding, an abdominal mass or torsion of the vascular pedicle causing venous congestion and acute abdominal pain, and eventually infarction. We present an unusual case of wandering spleen causing pancreatitis and gastric outlet obstruction via direct external compression.