Sonographic appearance of omental infarction in children

BACKGROUND

Omental infarction has been previously reported in the adult surgical and imaging literature; however, the imaging features of this entity in children have received little attention.

OBJECTIVE

The purpose of our study was to identify the sonographic features of omental infarction in nine children who had preoperative sonography and surgically proven omental infarction.

MATERIALS AND METHODS

Sonographic images were reviewed and correlated with clinical information obtained from the patients' medical records, including clinical presentation, operative notes, and pathology reports.

RESULTS

In seven of the children, sonography demonstrated a focal area of moderately increased echogenicity in the omental fat in the right abdomen (a previously described finding in omental infarction). This was an isolated finding in four of these cases. In the three cases where this was not an isolated finding, the more complex sonographic appearance led to incorrect preoperative imaging diagnoses. This finding of increased echogenicity in the omental fat was not present in the two remaining patients.

CONCLUSION

Our study confirms that foci of moderately increased echogenicity in the omentum of the right abdomen, a sonographic finding described in omental infarction in a large series in adults (and in a single prior case report in children), can be seen in children as well. However, although this is a relatively unique finding, it may be absent in some cases or may be seen in conjunction with other sonographic findings which may preclude the correct preoperative sonographic diagnosis.

Hyperechoic foci in the thalamic region imaged via the posterior fontanelle: a potential mimic of thalamic pathology

BACKGROUND

We have incidentally noted foci of increased thalamic echogenicity (FITE) on cranial sonographic images obtained via the posterior fontanelle (PF) that were not confirmed on images obtained while scanning through the anterior fontanelle (AF). Therefore, we postulated that this is a normal variant of PF imaging rather than true thalamic pathology.

OBJECTIVE

The purpose of this study was to determine the incidence of FITE detected on posterior and anterior fontanelle images.

MATERIALS AND METHODS

Parasagittal images were obtained bilaterally through the trigone of the lateral ventricles (including the thalami) via both the anterior and posterior fontanelles in 15 consecutive neonates (30 thalami) and evaluated independently by two pediatric radiologists for the presence or absence of FITE. Thalami were graded as grade 0 (no FITE), grade 1 (possible FITE), or grade 2 (definite FITE). Follow-up CT (n = 3) and MR (n = 1) were reviewed.

RESULTS

FITE were absent in 87 % of thalami imaged via the AF, and possible FITE were present in 13 % of these cases. No cases of definite FITE were identified via the AF. However, possible FITE were identified in 33-40 % of thalami and definite FITE were seen in 33 % of thalami imaged via the PF.

CONCLUSIONS

FITE seen only on images obtained through the PF on cranial sonography are a normal finding and should not be attributed to thalamic hemorrhage or ischemia.

Correlation of ultrasound with postmortem neuropathologic studies in neonates

We examined the correlation between cranial sonogram and postmortem examination neurodiagnoses in 51 infants (30 boys and 21 girls) who underwent cranial sonogram before death. The mean gestation of the infants at birth was 32 weeks 6 days; the mean birth weight, 1,992 gm; and the mean survival, 27 days. Most infants had several postmortem examination neurodiagnoses; therefore the postmortem examination diagnosis considered to be most significant in terms of clinical management and long-term neurologic function was chosen for each infant and designated as the primary diagnosis. The ability of the cranial sonogram to diagnose the primary diagnosis was then evaluated. The accuracy of the cranial sonogram in defining primary diagnoses was 59%. There were 21 cases (41%) in which cranial sonogram failed to define the primary diagnosis; nine of these could be explained on the basis of the timing of the ultrasound in relation to the age of the lesion or to the microscopic nature of the lesion. In 12 patients the factors causing the failure of cranial sonogram to define primary postmortem examination diagnoses could not be identified. The positive predictive value of a cranial sonogram diagnosis was 77%; the negative predictive value was 19%.

Hyperechoic caudate nuclei: a potential mimic of germinal matrix hemorrhage

BACKGROUND

We have encountered bilateral hyperechoic foci in the region of the germinal matrix on cranial sonograms in neonates that have an appearance similar to germinal matrix hemorrhage (GMH), but are unusual either due to the age of the patient at presentation or to the evolution of the foci on follow-up. We believe that these findings represent hyperechoic caudate nuclei (HCN) rather than GMH.

OBJECTIVE

To demonstrate that bilateral HCN can be seen on cranial sonography in neonates and can mimic bilateral GMH.

MATERIALS AND METHODS

The cranial sonograms were reviewed in nine neonates (three term and six premature) who had HCN identified on at least one sonographic examination. CT (two patients) and MR (one patient) studies were also reviewed, as well as the neuropathological examination in one patient who died and had an autopsy. The patients' medical records were reviewed to identify any clinical markers for significant risk of perinatal ischemia.

RESULTS

There was clinical evidence for risk of ischemia in five of the nine neonates. All nine patients had bilateral HCN on the initial or follow-up studies. Small cysts were seen sonographically in two patients. CT was normal in one patient and revealed a small unilateral focus of increased attenuation in one infant (very small compared to the bilateral HCN). MR was normal in one patient. Histopathological examination of the brain was normal in the one patient who died and had an autopsy.

CONCLUSION

Hyperechoic caudate nuclei can occur in neonates either as a normal finding, or possibly related to ischemia, and should not always be attributed to GMH.

Simple renal cysts in children with AIDS

Simple renal cysts are very uncommon among children. Of 50 children with AIDS that underwent computed tomography at our hospital, 4 had radiographically simple cysts. The incidence of simple renal cysts in this group of children is thus approximately 45 times that seen in normal children. To our knowledge, simple renal cysts have never been reported as a manifestation of AIDS in children. It is unknown whether or not these cysts are a manifestation of HIV nephropathy (HIVN), in which microcysts are seen pathologically. We suggest that simple renal cysts may be a finding compatible with the diagnosis of HIVN.

Medical students' attitudes toward radiology: comparison of matriculating and graduating students

RATIONALE AND OBJECTIVES

To determine graduating medical students' perceptions of radiology and to document changes in their perceptions since they entered medical school.

MATERIALS AND METHODS

A survey questionnaire was distributed to 213 graduating students. Questions were similar to those answered by the same group of students as they entered medical school nearly 4 years earlier.

RESULTS

The survey was anonymously completed by 140 students. Seventy percent of students changed their choice of medical specialty since entering medical school. Factors with a major or important influence on specialty choice included intellectual excitement (96%), high patient contact (86%), opportunity for a good family life (72%), and regular hours (57%). Radiology was perceived to be a well-paid (89%), "high-tech" (86%) specialty with a healthy lifestyle (82%), regular hours (99%), and good family life (92%), but it was not perceived to offer high patient contact (1%) and was intellectually exciting to only 33% of students. This perception was unchanged from freshman year.

CONCLUSIONS

This 4-year longitudinal study of a medical student class documents surprisingly little change in the perception of radiology throughout medical school. High patient contact and intellectual excitement, both factors of major or important influence on specialty choice, were thought to be lacking in radiology.

Mechanical factors associated with posterior rib fractures: laboratory and case studies

OBJECTIVE

The objective of this study was to explore the mechanical factors associated with posterior rib fractures.

MATERIALS AND METHODS

Radiographs were reviewed in ten cadavers where rib fractures were produced by opening a median sternotomy with a sternal retractor. A second study used CT to evaluate for rib fractures following digital sternal depression and anteroposterior bimanual thoracic compression in three rabbits. Lastly, two cases of accidental posterior rib fractures in children were reviewed.

RESULTS

In the cadaver studies, ten rib fractures were noted, all at or medial to the costotransverse process articulations. In the rabbit study, 13 posterior rib fractures were noted, all occurring with excessive posterior levering of the ribs during bimanual compression. The accidental posterior rib fractures occurred with severe anteroposterior thoracic compression as children were decelerated into a car dashboard or struck by a car.

CONCLUSION

Posterior rib fractures require excessive levering of the posterior ribs at the costotransverse process articulation. When these fractures occur in accidental situations, they require massive forces that entail similar mechanics to those occurring in abusive settings.

Performance on the radiology component of a critical clinical skills examination

RATIONALE AND OBJECTIVES

Clinical competence certification is now required in some specialties in medicine. A Comprehensive Clinical Assessment (CCA) was created to test mastery of critical skills by students at the end of the 3rd year of medical school.

METHODS

The CCA is a series of stations that test skills the faculty consider important for all medical students (eg, breast examination, electrocardiogram reading, chest pain assessment, ophthalmology photographs). The radiology station was designed to evaluate imaging skills believed to be taught and learned in the core 3rd-year rotations.

RESULTS

External measures (National Board Examinations, grade point average, and overall score) of clinical performance of the 608 medical students who completed the CCA examination between 1991 and 1993 were found to be correlated with the radiology station scores.

CONCLUSION

The radiology station in the CCA examination is a reproducible measure of clinical performance.

Magnetic resonance imaging in congenital heart disease in children

Images

Congenital mesoblastic nephroma metastatic to the brain: a report of two cases

Congenital mesoblastic nephroma was originally believed to be a universally benign neoplasm. More recently, aggressive congenital mesoblastic nephromas have been described with local recurrence and/or metastases. We report two patients with documented congenital mesoblastic nephroma which later metastasized to the brain.

Estimation of total lung capacity from chest radiography and chest CT in children: comparison with body plethysmography

OBJECTIVE

The purpose of this study was to evaluate two methods of estimating lung volume using chest radiographs and one using chest CT in children. Estimates made with these techniques were compared with total lung capacity calculated with body plethysmography.

MATERIALS AND METHODS

CT scans and posteroanterior and lateral radiographs of the chest were obtained in 21 children (14 girls and seven boys) for follow-up evaluation after lung transplantation. Lung volume was measured by CT using a previously validated technique of tracing the margins of the lungs on each axial CT scan. Two methods were used to estimate lung volume on chest radiographs: a technique previously described in adults and children that requires 21 measurements on posteroanterior and lateral radiographs, and a modification of a simplified technique previously reported in adults that uses only two measurements on a posteroanterior radiograph alone. Estimated lung volumes from CT and from both methods using chest radiographs were compared with total lung capacity determined from body plethysmography using regression analysis, and 95% prediction intervals were generated.

RESULTS

All three methods of estimating lung volumes from radiographs correlated well with total lung capacity from plethysmography (r = .89-.92). However, we found no statistically significant or clinically meaningful difference among the methods of estimating lung volume.

CONCLUSIONS

Lung volumes in children can be accurately estimated from specific measurements made on chest radiographs and on CT scans. Of the two methods tested with chest radiographs, the technique that required only two measurements from a posteroanterior chest radiograph was as accurate as the more complicated technique that required 21 measurements.

Ureteropelvic junction obstruction in infants mimicking ureterovesical junction obstruction on sonography

We present two infants with ureteropelvic junction obstruction with very large renal pelves, which extended to the level of the urinary bladder. In both cases, the distal aspect of the renal pelvis simulated a dilated distal ureter, leading to the incorrect sonographic diagnosis of ureterovesical junction obstruction. Awareness of this potential pitfall on sonography is important when imaging infants with prenatal diagnosis of hydronephrosis.

MR of right aortic arch with mirror-image branching and a left ligamentum arteriosum: an unusual cause of a vascular ring

An unusual case is presented of a vascular ring due to a right arch with mirror-image branching and a left ligamentum arteriosum from the descending aorta to the left pulmonary artery. There have been only four previous reports of this rare arch anomaly. In addition, the patient had no underlying congenital heart lesions, which is also very unusual in patients with right aortic arch with mirror-image branching.

Splenic volume in children: simplified estimation at CT

Measurements of splenic length, width, and thickness were obtained from axial computed tomographic (CT) scans in 50 consecutive children (26 male and 24 female patients, aged 8 days to 19 years) referred for abdominal CT. In addition, the outline of the spleen was traced on individual axial CT sections to obtain the splenic volume with use of the software program in the CT computer. The three splenic dimensions correlated well (r = .97) with the splenic volumes obtained with the more accurate technique of tracing the splenic outline on sequential CT sections.

Resolution of splenic injury after nonoperative management

Numerous studies have demonstrated success with nonoperative management of splenic injuries in pediatric patients. However, the resolution of the splenic injury has not been previously evaluated. The records of 50 pediatric patients with splenic injuries from blunt trauma treated nonoperatively between 1984 to 1992 were reviewed retrospectively. Abdominal computed tomography (CT) was performed at the time of injury and 6 weeks postinjury in 25 patients. These scans were reviewed and categorized by a modification of a previously reported grading system for parenchymal injury. All patients had healing of the splenic injuries, with complete resolution of the healing process observed at 6 weeks postinjury in 44%. Even those with shattered spleens (n = 6) had consistent improvement in splenic architecture, with resolution of fractures and/or contusions and return of splenic perfusion. Ten (77%) of 13 grade 1 and 2 injuries were completely resolved by the 6-week follow-up examination, whereas only one (8%) of 12 grade 3 to 5 injuries showed radiological resolution of splenic injuries. None of the 25 follow-up CT scans affected clinical decision-making or led to a deviation from the established protocol, which included a 3-month period of reduced activity. All 50 patients did well, without evidence of morbidity, mortality, or complications after return to full activity 3 months postinjury.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiographic lung disease and response of persistent pulmonary hypertension to mean airway pressure and alkalosis

Persistent pulmonary hypertension of the newborn (PPHN) is associated with multiple cardiopulmonary diseases. Therapy often includes hyperventilation/alkalosis despite little evidence as to its efficacy in diverse conditions. To determine (1) if part of the improvement of arterial oxygen tension (PaO2) attributed to alkalosis is actually related to increased mean airway pressure (P(aw)) and (2) if the presence of radiographic pulmonary disease predicts the response to alkalosis or mean airway pressure, we reviewed records of 19 newborns with well-documented PPHN. Arterial blood gases and corresponding ventilator settings were recorded during the first day of life. To adjust for lower FiO2, corrected PaO2 (cPaO2) was calculated when the FiO2 < 1.0, such that cPaO2 = calculated arterial/alveolar oxygen ratio x (713 - PaCO2/0.8). Regression equations were obtained and mean slopes of these were compared for P(aw) vs. cPaO2, and pH vs. cPaO2 by one group t-tests (with assumed population slope of zero). There was no correlation between P(aw) and cPaO2 (mean slope +/- SD = -8.4 +/- 30.8, P = 0.25), but there was a moderate correlation between pH and cPaO2 (mean slope = 333.1 +/- 480.5, P = 0.007). Patients were then classified by chest radiographs as having severe or minimal/no lung disease. Relationships of P(aw) and pH to cPaO2 were then re-examined. No correlation was present between P(aw) and cPaO2 in 11 patients with PPHN and severe radiographic disease (mean slope = -7.4 +/- 26.9, P = 0.38) or in eight patients with PPHN and minimal/no lung disease (mean slope = -9.8 +/- 37.5, P = 0.48).(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation dose reduction in CT of the pediatric pelvis

PURPOSE

To determine whether a lower radiation dose technique can be used for computed tomography (CT) of the pediatric pelvis without significant loss of diagnostic image quality.

MATERIALS AND METHODS

Thirty-six pediatric patients underwent CT at 80 mAs (experimental group), and 42 underwent CT at 240 mAs (control group). Anatomic details, image quality, and the degree of confidence in reaching a diagnosis were graded on a scale of 1 (poor) to 4 (excellent).

RESULTS

The difference in perceived image quality between the experimental and control groups was not statistically significant. The mean scores for scans evaluated by the first reader were 3.88 for the experimental group and 3.92 for the control group (P = .2804). The mean scores for the second reader were 3.78 and 3.77 for the experimental and control groups, respectively (P = .8131).

CONCLUSION

A substantial dose reduction can be achieved if pelvic CT is performed at 80 mAs, without a recognizable deterioration of diagnostic image quality.

Utility of sonography in the diagnosis of bronchopulmonary sequestration

Sonography in six patients with pulmonary sequestration demonstrated findings associated with and indicative of that diagnosis. The most useful feature, which was seen in three cases and is diagnostic of sequestration, is the identification of an anomalous systemic artery arising from the aorta.

Indium-111 leukocyte uptake in a patient with osseous metastatic Ewing's sarcoma

A case of increased uptake of in-111 labeled leukocytes in osseous metastasis from Ewing's sarcoma is presented. Bone scan and MRI findings were concordant with the indium scan, and biopsy confirmed Ewing's metastasis. Although relatively specific for infection, indium infrequently does demonstrate abnormal bone uptake in several malignancies. This case report is the first to describe indium uptake in osseous metastatic Ewing's sarcoma. Possible mechanisms of indium leukocyte localization are discussed.

Volume of the spleen in children as measured on CT scans: normal standards as a function of body weight

OBJECTIVE

The purpose of this study was to develop standards for the normal volume of the spleen in children as measured on CT scans.

SUBJECTS AND METHODS

CT scans were used to measure the volume of the spleen in 48 children (30 boys and 18 girls), 1 day to 18 years old (mean and median ages were 8.2 and 7.8 years, respectively). Children who had underlying malignant tumors, infection, hematologic diseases, or other conditions that could alter splenic size were excluded. The area of the spleen on each axial section was determined by tracing its outline on the CT monitor and measuring the area of the region of interest. The area of the spleen on each section was multiplied by the slice thickness to calculate the volume of the spleen for each section. The total volume of the spleen was then determined by adding the individual volumes for each of the sections through the spleen. This method of calculating splenic volume has been validated in previous studies in adult subjects. The volume of the spleen was analyzed as a function of both body weight and age.

RESULTS

The volume of the spleen correlated better with body weight than with age. The best regression model (r = .85) was a linear relationship as follows: splenic volume (cm3) = 0.7 + [4.6 x weight (kg)]. Using these data and a regression model, we generated standards for normal volume of the spleen as a function of body weight (with 95% tolerance intervals).

CONCLUSION

We have developed CT standards for normal splenic volume in children. These standards can be used to objectively measure the size of the spleen in children who have clinically suspected splenomegaly.

Ilio-psoas abscess in neonates

We report two cases of primary ilio-psoas abscess in neonates diagnosed by CT and sonography. Ilio-psoas abscess is extremely uncommon in this age group.

Radiography of thoracic intravascular stents in children with congenital heart disease

Seventeen balloon expandable stents were placed in thoracic vessels in eleven children with vascular stenoses related to congenital heart lesions. We describe the normal radiographic appearance of three types of balloon expandable stents implanted in pulmonary arteries, pulmonary veins, and the superior vena cava of these children as well as the appearance of the complications we encountered. Knowledge of the radiographic appearance of these devices is important as chest radiography is a primary method of follow-up in children with balloon expandable stents placed to treat stenoses of intrathoracic vessels related to congenital heart disease.

Transcatheter atrial septal defect occlusion devices: normal radiographic appearances and complications

Three transcatheter atrial septal defect (ASD) occlusion devices have been used in clinical trials during the past decade: the Rashkind ASD occluder, the Lock Clamshell occluder, and the buttoned double-disk device. The normal radiographic appearance of these three devices and radiographic findings in complications are presented. Of 12 transcatheter ASD occlusions performed, the buttoned double-disk device was used in eight patients, the Rashkind ASD occluder in three, and the Lock Clamshell occluder in one. Complications included both improper placement and partial dislodgment of the Rashkind ASD occluder device (n = 2), fracture of a metal arm of the Lock Clamshell device (n = 1), and detachment of the buttoned double-disk device with embolization into the right pulmonary artery (n = 1). Knowledge of the normal radiographic appearance of ASD occlusion devices and the findings in various complications will be necessary for radiologists as transcatheter ASD closure becomes more commonplace. Chest radiography is the primary method of detecting short- and long-term complications in patients following transcatheter ASD closure.

Diseases of the musculoskeletal system in children: imaging with CT, sonography, and MR

We reviewed the applications of CT, sonography, and MR imaging in diseases of the musculoskeletal system in children. Unique advantages of each technique are discussed, and common disease entities and practical applications of the three imaging methods are stressed. Evaluation of congenital dysplasia of the hip, hip effusion, and soft-tissue foreign bodies with sonography are emphasized. The role of CT in imaging patients with congenital dysplasia of the hip, tarsal coalition, osteomyelitis, and benign and malignant bone tumors is stressed. Common applications of MR that are emphasized include imaging of osteomyelitis, musculoskeletal tumors, normal bone marrow, and avascular necrosis. Innovations are briefly discussed, including evaluation of dermatomyositis with MR and imaging sternoclavicular dislocation, congenital vertical talus, and fractures and dislocations with sonography.

First-year medical students' attitudes toward radiology

To explore the perspectives of entering medical students, a questionnaire was completed anonymously by 171 students in September of their first year of medical school. The authors investigated their attitudes toward radiology relative to other specialties and their perspective concerning which factors would influence their eventual choice of a specialty. Upon entering medical school, 33.3% of the students indicated that they had chosen a specialty, and 7.4% of these students had selected radiology. Radiology was perceived as a well-paid specialty with a pleasant lifestyle. These are factors that were perceived as very important regarding influence on eventual choice of specialty. However, radiology was believed to have an undesirably low level of patient contact and was perceived as not being intellectually exciting. We plan to follow this group of students prospectively through medical school to see whether their attitudes change toward radiology as a career.

Carpo-metacarpal growth disturbance and the assessment of carpal narrowing in children with juvenile rheumatoid arthritis

Second metacarpal length (M2), radio-metacarpal length (RM), and intermetacarpal width (W) were measured on 96 radiographs in 52 children with polyarticular juvenile rheumatoid arthritis (JRA), and compared with body height and skeletal maturation in order to: (1) differentiate between processes resulting in retardation of bone growth and those producing delay in skeletal maturation; (2) assess the severity and progression over time of such retardation; and (3) assess the impact of retardation of the second metacarpal on the assessment of carpal narrowing in children with JRA. All measurements were converted into z scores (the units of standard deviation above or below the normal mean for each measurement) based on published norms. Retardation of M2 (mean z scores -0.91) began earlier and was more severe compared with retardation of height (mean z score -0.25). This disproportion widened with increasing duration of disease. That this primarily represents a disturbance in M2 growth rather than a secondary effect due to altered maturation is suggested by the bone ages being normal (mean z score 0.14) and the absence of premature closure of the metacarpal physes. Z scores for RM/W (mean -3.53) were at least 1 Z more negative than for corresponding measurements of RM/M2 (mean -2.41) in 47 (90.4%) children and the mean difference between the z scores for RM/W was -1.12. This discrepancy between RM/W and RM/M2 was eliminated by correcting for the reduction in M2.

Interobserver and intraobserver variations in sonographic renal length measurements in children

Sonographic measurement of renal length is used commonly to evaluate growth of the kidneys in children. However, no previous studies have been performed to determine the degree of interobserver and intraobserver variability in such determinations. We measured the interobserver and intraobserver error in sonographic measurements of renal length obtained independently by three experienced imagers in 21 children (41 kidneys). The mean interobserver variation between any two imagers ranged from 3.87 to 5.49 mm. The mean intraobserver variation was 0.87 to 3.61 mm. The observed variability in sonographic measurement of renal length is comparable to the expected annual increase in length of the kidneys during childhood (2.2-5.7 mm per year). Therefore, caution is suggested when using sonography to evaluate renal growth in children during a year's time.

Radiographic imaging of airway obstruction in pediatrics

The authors review techniques available to image the airway, normal radiographic airway anatomy, pitfalls in imaging the airway, and radiographic findings in various pathologic processes that may cause airway obstruction. A brief discussion of the application of imaging in the child with sleep apnea is included.

Ileal duplication cyst: repeated spontaneous decompression delays diagnosis

A duplication cyst of the ileum was initially observed in a fetus at 26 weeks gestation on prenatal ultrasonography. Repeated spontaneous resolution of the cyst by decompression into the adjacent bowel lumen delayed diagnosis and management until the child was 9 months of age. The child experienced two episodes of hemorrhage from the cyst as a result of the delay in diagnosis.

Unusual radiographic manifestations of chondrodysplasia punctata

We present six cases of chondrodysplasia punctata with radiographic findings that are either very rare or previously unreported in this entity.

Chest wall mesenchymoma (hamartoma) in infancy. CT and MR findings

A case of a chest wall mesenchymoma in a five month old infant is presented, and the role of CT and MR are emphasized. There have been no prior reports of the CT or MR findings in this entity.

Sonography of the nonossified tarsal navicular cartilage in an infant with congenital vertical talus

Sonography was performed to visualize the nonossified tarsal navicular cartilage and to demonstrate talonavicular dislocation in a seven month old infant with congenital vertical talus.

Enlarged common hepatic duct secondary to morphine in a neonate

A neonate with reversible, nonobstructive common hepatic duct enlargement secondary to intravenous morphine administration is presented.

Normal standards for kidney length in premature infants: determination with US. Work in progress

In 52 healthy premature infants, 104 kidneys were sonographically examined and kidney length was measured. Kidney length was compared with four parameters: body weight, body length, body surface area, and gestational age. Scatter plots of these data demonstrated that kidney length versus body weight conformed well to a linear distribution with a high correlation coefficient. A nomogram for kidney length versus body weight in premature infants is also presented.

Intraosseous rheumatoid nodule

The authors present a case of an intraosseous rheumatoid nodule in the rib of a 9-year-old boy.

Elliptical cricoid cartilage: a unique type of congenital subglottic stenosis

An elliptically shaped cricoid cartilage, a specific type of congenital subglottic stenosis, is described, and the laryngoscopic and radiographic findings in three cases are discussed. An "hourglass" deformity of the subglottic laryngeal airway on an anteroposterior airway radiograph is suggestive of this diagnosis.

Distal femoral epiphysis: normal standards for thickness and application to bone dysplasias

Flattening of the epiphysis of the long bones is seen in several bone dysplasias. It is the hallmark of multiple epiphyseal dysplasia and is an important sign in the diagnosis of spondyloepiphyseal dysplasias, diastrophic dysplasia, and pseudoachondroplastic dysplasia. The goal of this study was to determine norms for the height of the distal femoral epiphysis and to apply these standards to patients with bone dysplasias. Ratios of the distal femoral epiphysis height to both the distal femoral metaphysis width and the distal femoral epiphysis width were obtained from 640 radiographs of healthy children of different ages. Application of these standards to 41 patients with the bone dysplasias mentioned above proved useful in ascertaining decreased height of the distal femoral epiphysis. These standards are of particular value in subtle or early cases in which the thinning of the epiphysis may not be apparent upon simple observation. Obtaining three simple measurements from the anteroposterior knee radiographs allows determination of the presence or absence of flattening of the epiphysis.

Dense pulmonary opacification in neonates treated with extracorporeal membrane oxygenation

Chest radiographic findings in three neonates with respiratory failure secondary to meconium aspiration treated with extracorporeal membrane oxygenation (ECMO) are described. The degree of pulmonary opacification on the chest radiographs failed to correlate with the patients' clinical status as measured by the arterial oxygen levels but correlated well with the peak airway pressure (PAP) and continuous positive airway pressure (CPAP) settings on the mechanical ventilator. Because a variable portion of the arterial blood oxygenation is performed by the extracorporeal membrane oxygenator and unusually large fluctuations in airway pressure settings can occur in these patients while on ECMO, it is important to realize that the chest radiograph may not be an accurate predictor of the patients' clinical status.

Flattening of the distal femoral epiphyses in the trichorhinophalangeal syndrome

A new finding in the trichorhinophalangeal syndrome, flattening of the distal femoral epiphyses, is described in seven patients. Measurement of the ratio of the height of the distal femoral epiphysis versus both the width of the distal femoral metaphysis and the width of the distal femoral epiphysis and comparison to normal standards confirmed the subjectively observed flattening of the distal femoral epiphysis in these patients, further suggesting that the disease is a generalized process rather than a local disorder.

Pericardial effusion presenting as an anterior mediastinal mass

The authors present a case of pericardial effusion in a patient with previous cardiac surgery. Because the pericardium is opened and not reclosed during surgery, fluid can extend superior to the normal upper reflections of the pericardium and simulate an anterior mediastinal mass.

Concurrent hydromyelia and diastematomyelia

Hydromyelia was discovered in six of 13 patients with diastematomyelia. In one patient, hydromyelia affected only the segments of spinal cord above the diastematomyelia. In five patients, hydromyelia extended downward from the single cord into one or both hemicords. Because hydromyelia and diastematomyelia occur simultaneously, because they may produce very similar clinical changes, and because simultaneous or sequential surgical correction of both conditions may be necessary to achieve the best clinical result, the possibility of hydromyelia should be evaluated specifically in each patient demonstrated to have diastematomyelia.

Calcification and ossification in a congenital mesoblastic nephroma

Calcification is uncommon in any of the intrarenal tumors of childhood. A 6-month-old girl with multiple dense intrarenal calcifications was found to have congenital mesoblastic nephroma.

Postintubation granuloma of the anterior subglottic larynx

We present an unusual case of a granuloma in the subglottic laryngeal airway of a 6-week-old infant with a history of previous endotracheal intubation. Postintubation granuloma formation in this region has not been previously reported in infants.