Experienced Pediatric Radiologist Research Articles

Unilobar congenital pulmonary lymphangiectasis mimicking congenital lobar emphysema: an underestimated presentation?

Background Congenital lobar emphysema (CLE) is characterized by unilobar alveolar distension secondary to bronchomalacia or absent cartilage. In contrast, congenital pulmonary lymphangiectasis (CPL) is defined as distended lymphatics in the bronchovascular bundle, in the interlobular septa, and in the subpleural space. Little information is available regarding the radiologic presentation of CLE as it correlates with histological diagnosis. Methods In a retrospective chart review from 1995 to 2002, 8 patients (5 boys and 3 girls) with clinical and radiologic diagnosis of CLE were reviewed. Results The mean age at diagnosis was 26 months (range, 11 days to 10 years). All but one had classic respiratory symptoms of CLE. Six of 7 chest computed tomography (CT), scans were suggestive of CLE. Of 8 patients, 3 were treated without pulmonary resection with resolution of symptoms. Five patients underwent lobectomies, and histology results showed CPL in 3. CT failed to identify CPL in all cases. Conclusions Diagnosis of CLE is not as straightforward as the literature suggests. Even retrospectively, radiologic distinction between CLE and CPL could not be achieved by an experienced pediatric radiologist. CPL, thus, mimics CLE clinically and radiologically and, therefore, should be considered in the differential radiologic diagnosis of CLE.

Reliability of cranial CT versus intracerebral pressure measurement for the evaluation of generalised cerebral oedema in children.

To examine the extent to which intracranial pressure (ICP) in children after severe brain trauma can be determined by cranial CT. Two experienced paediatric radiologists, without any knowledge of the clinical symptoms, evaluated 124 CT scans from 65 children (average age 5.4 years) who underwent intracranial measurement of their cerebral pressure. CT had high sensitivity (99.1%) for 'high cerebral pressure' but a much lower specificity (78.1%). The examiners tended to estimate ICP as 'high' even when actual ICP was low. Since therapy for lowering cerebral pressure involves potential risks, actual cerebral pressure measurement, particularly in children, should be considered before intervention (e.g. hyperventilation or trepanation). We report the change in different intracerebral fluid compartments with varying cerebral pressure and modifications of the density of the brain tissue in an inter- and intraobserver comparison. The radiologist cannot differentiate, for methodological reasons, between a change in the intracranial fluid compartments not associated with a change in ICP and one in which it is critically elevated. Before any interventional treatments such as decompression-trepanation or hyperventilation are instituted, measurement of ICP should be considered, especially in children.

The reliability of bone age determination in central European children using the Greulich and Pyle method.

This study assessed the reliability of bone age determination in normal central European children using the Greulich and Pyle method and determined the effects of readers' experience on the measured bone ages. Plain hand radiographs of 47 children (aged 2 months to 18.8 years) with normal growth were analysed by four radiologists (two experienced paediatric radiologists and two radiology residents). The readers were blinded to the age of the children. The images were re-read by the same readers 2 months later. The mean intraobserver and interobserver variations were lower for experienced readers than for radiology residents. However, these differences were not statistically significant at the 5% level. The difference between the chronological age and the measured bone age was -1.5 +/- 7.6 months (p = 0.20) for the experienced readers and 2.7 +/- 10.3 months (p = 0.09) for the radiology residents. The differences between the measured bone age and chronological age were statistically significant (p = 0.04) for only one of the two radiology residents. Although the measurements by all four readers underestimated the chronological age, the differences between chronological age and bone age were within the normal variations of skeletal maturation as reported by Greulich and Pyle. Our data suggest that the reliability of bone age measurements increases with experience and that the Greulich and Pyle method may be used for central European children.

Variation in the diagnosis of vesicoureteric reflux using micturating cystourethrography.

Variability in the interpretation of micturating cystourethrography by paediatric radiologists for the diagnosis of vesicoureteric reflux in children was evaluated. All 265 micturating cystourethrograms (MCUs) that were available from 304 consecutive children aged 0.5-61 months-who were investigated after their first urine infection between 1993 and 1995 as part of a prospective cohort study-were selected for interpretation. Three experienced paediatric radiologists from the same department independently interpreted the MCUs according to the grading system of the International Reflux Study in Children, from grades 0 to V, with the presence of intrarenal reflux also noted. Apart from being informed that urine infection was the indication for the MCU, no other clinical information was given to the radiologists. The indices of variability used were the percentage of agreement and the kappa statistic, expressed as a percentage. Both measures were weighted with integers representing the number of categories from perfect agreement. Disagreement was analysed for children and kidneys. For the diagnosis of vesicoureteric reflux in individual patients, including grade, the percentage of agreement was 96%-97% (kappa 90%-91%) and the weighted percentage of agreement was 96%-98% (weighted kappa 93%-94%). The same high level of agreement was present for individual kidneys, with a percentage of agreement of 97%-98% (kappa 89%-92%) and a weighted percentage of agreement of 98%-99% (kappa 94%-95%). There was near perfect agreement in the interpretation of radiological micturating cystourethrography among three experienced paediatric radiologists for the diagnosis and grade of vesicoureteric reflux. Any variations in the medical care of children suspected of having vesicoureteric reflux are not explained by differences in the reporting of this diagnostic test.

MRI examination and monitoring of pediatric patients under sedation.

From April 1992 to May 1994, 780 patients aged from 1 day to 8 years were examined. Sedation of these patients was conducted by giving chlorprothixene orally and, in some cases, chloral hydrate had to be added. The patients were monitored with a pulse oxymeter. Investigations could begin after 50 -120 min. In 710 patients (91%) the first attempt to perform the examination was successful; 70 patients required one or two further attempts. Only two of the 780 patients (0.5%) showed evidence of respiratory depression. The total number of pediatric MRI examinations performed in 1 year is almost 1000. In the hands of an experienced pediatric radiologist these examinations can be performed entirely without anesthesia.

Pediatric skeletal age: determination with neural networks.

To develop a neural network to calculate skeletal age based on measurements taken from digitized hand radiographs. From a database of 521 hand radiographs obtained in healthy patients, four parameters were calculated from seven linear measurements and were used to train a neural network, with use of the jackknife method, to calculate skeletal age. The results were compared with those of an experienced pediatric radiologist using a standard pediatric skeletal atlas. The mean difference from biologic age for the neural network was -0.261 years +/- 1.82 (standard deviation) and for the radiologist, -0.232 years +/- 1.54; this difference was not significantly different (P = .67, Wilcoxon signed rank test). Skeletal age determined by the neural network was closer to the biologic age than that assigned by the radiologist in 243 of 521 cases (47%). A simple neural network may assist radiologists in the assessment of skeletal age.

Are hydrostatic and pneumatic methods of intussusception reduction comparable?

The hydrostatic pressures and flow rates of barium sulphate and water soluble contrast in concentrations representative of those used for intussusception reduction were measured. The change of height with discharge of fluid from the filled kit was also assessed. A group of experienced paediatric radiologists and radiographers significantly underestimated the height to which contrast should be placed for intussusception reduction. The results indicate that baseline hydrostatic reduction pressures tend to be less and maximum pressures significantly less than those presently advocated for pneumatic reduction. This disparity may account for the apparent improvement in intussusception reduction rates reported for air enema when compared with barium enema. Intraluminal pressure monitoring during contrast enema would aid control of intussusception reduction but hydrostatic reduction would still be at a disadvantage because of lower flow rates. Where hydrostatic reduction is performed, the contrast density and height used should be set to give known pressure, according to local guidelines.

Neural Networks in Radiologic Diagnosis; II. Interpretation of Neonatal Chest Radiographs

A neural network (NN) system was trained to choose one or more diagnoses from a list of 12 possible diagnoses, based on 21 radiographic observations made on each of a series of neonatal chest radiographs. Initially, an experienced pediatric radiologist provided both the radiographic observations and ranked differential diagnoses for each of 77 neonatal chest radiographs in the preliminary phase used to train the NN. Subsequently, two pediatric radiologists (one of whom provided the initial training-phase data) independently read a series of 103 neonatal chest radiographs (different from the training set) and compiled a list of radiographic findings and differential diagnoses for each radiograph. The trained NN was then asked to provide a list of differential diagnoses for each case from the radiologists' lists of findings. Agreement between the network and each radiologist independently was greater than between the two radiologists. Both the positive and negative agreement between the network and either radiologist was greater than the inter-radiologist agreements for most of the diagnostic endpoints.

Diagnostic quality of portable abdominal radiographs in neonates with necrotizing enterocolitis: digitized vs nondigitized images.

Digital manipulation of radiographic images has prompted significant interest because of the potential for improving image quality and diagnostic accuracy. We compared conventional and digital radiographs in the evaluation of neonatal necrotizing enterocolitis (NEC). Fifty abdominal radiographs in neonates with suspected or autopsy-confirmed NEC and 50 similar radiographs of neonates without suspicion of NEC were digitized. Definition of intraabdominal anatomy was optimized by window width and level adjustment. Hard-copy radiographs of the digitally manipulated images were then produced by a laser printer. Twelve general radiologists each evaluated, without benefit of clinical information, a random mixture of 50 cases of NEC and normal controls, with both conventional and digital images for each case, for a total of 100 radiographs reviewed. Each image was evaluated for overall suspicion of NEC and the presence and severity of six radiographic signs of NEC. The radiologists also rated their confidence in their assessments. The results were compared with those from a similar analysis by an experienced pediatric radiologist to ensure validity of image evaluation. No statistically significant differences were found between the conventional and digital imaging formats for the assessment of the signs of NEC (p = .15) or for determination of the overall suspicion of NEC (p = .07). Our results show the digitized and the conventional, nondigitized radiographs to be at least equally useful for evaluating the radiographic signs of NEC and suggesting an appropriate diagnosis.

Proximal fistula in esophageal atresia: pitfall in a routine procedure

Proximal fistulae occur only infrequently in esophageal atresia. Type B atresia is seen in 0%–3% and type D atresia in 0.25%–7.7%. In the past 16 years 149 children with esophageal atresia have been treated in the Department of Pediatric Surgery of the University Hospital in Nijmegen. Only 2% and 4% had type B and type D esophageal atresia respectively. There were no routine preoperative contrast studies in this series. There was only a slight increase in morbidity in these patients due to a delay in diagnosing the proximal fistula. Routine preoperative contrast studies are not only time-consuming, but also do not guarantee visualization of the fistula, and the risk of contrast pneumonia always remains. Weighing the pros and cons of these observations, we think it unnecessary to perform extensive routine preoperative contrast studies in all patients with esophageal atresia. Contrast studies should be performed on clinical suspicion of a proximal fistula and should always be performed in close co-operation with an experienced pediatric radiologist. The proximal fistula can best be closed via a cervical incision.

Radiology of the Newborn and Young Infant

Pediatric radiology has grown rapidly over the past several years, and a number of texts on the subject have evolved, both in the general and limited aspects of the specialty. Dr. Swischuk has contributed a previous text on heart disease, as well as additions to the pediatric radiology literature. This book is limited, in most instances, to radiology of the newborn, but does cover some things one might be more likely to encounter in a slightly older age group. The style of presentation permits the inclusion of a large number of entities of both common and uncommon nature. The chapters deal with specific organ systems and begin with a description of normal findings, normal variants, and artefacts that should be useful for the person with little experience in pediatric radiology. The common entities are well-covered in their radiological findings and, in some conditions, clinically and pathologically as well. The less