The clinical usefulness of teleradiology of neonates: expanded services without expanded staff

Teleradiology was utilized to link an offsite, high-risk nursery to the Department of Pediatric Radiology of Children's Hospital of Michigan. Interpretations via teleradiology were made in 4200 examinations and taken as the final reading. There was no expansion of either professional or technical personnel at either hospital to accomplish these ends. During the initial 3 months of the study, 40% of the teleradiographic images were double-read to evaluate the accuracy of the technique. During the subsequent 9 months, 17% of the cases were double-read, for an overall double-reading of 23%. There was a 98% agreement between the interpretations made using teleradiology and those made using hard copy. In no instances of the 2% (20 cases) in which there was disagreement between readings did the difference have clinical significance. Our results indicate that teleradiology linkage for interpreting neonatal examinations serves as a valuable tool for expansion of subspecialty expertise, allows more expedient recognition of abnormalities in the neonate, and facilitates faster transport to the appropriate tertiary care center.

Congenital neuroblastoma: evaluation with multimodality imaging

The authors retrospectively evaluated 12 patients with congenital (neonatal) neuroblastoma to assess the utility of newer imaging modalities. Findings at prenatal ultrasound (US), performed in four patients, were nonspecific (hydramnios and hydrops fetalis) in two and consistent with a suprarenal mass (one solid, one cystic) in the other two. Postnatal US helped accurately detect adrenal tumors (solid or complex, with one exception) but was less accurate in the diagnosis of metastatic disease to the liver. Computed tomography accurately depicted all primary tumors and liver metastases. Magnetic resonance (MR) imaging helped establish the correct diagnosis in three patients. This study again confirmed the benign course of neonatal neuroblastoma, with 50% of the patients classified with stage IV-S disease and two deaths occurring in the series, both due to complications. Therefore, aggressive diagnostic imaging is less desirable, and US is therefore very useful, despite its limitations. The prenatal detection and solid appearance of a suprarenal mass makes the diagnosis of neuroblastoma very likely, as does the presence of liver lesions. In the absence of these characteristic findings, US should be repeated to exclude adrenal hemorrhage. MR imaging seems to be a good alternative in some instances.

Accuracy of ultrasonic bladder volume measurement in children

The accuracy of ultrasonography in assessing the bladder volume in 13 children with normal bladder contours was determined using the formula D x H x W (depth x height x width) with a mean error of 15.7%. This formula tends to overestimate the bladder volume in these patients. Multiplication by a correction factor of 0.9 yields a mean error of 11.5%. The accuracy of this evaluation is not dependent upon the bladder volume as the mean error was the same in those children whose bladder volume was either less than or greater than 150 cc. In addition, the accuracy of ultrasonography in assessing bladder volume was evaluated in 7 patients with an abnormal bladder contour (trabeculation, diverticula, etc.); mean error was 14.7%. In these 7 patients there was no predictable under or overestimation of bladder volume. In the children with abnormal bladder contours on ultrasound, the correction factor of 0.9 should not be used, as it does not add to the accuracy of the procedure in any individual patient. This technique is still valuable, however, in children with an abnormal bladder for it allows estimation of the extent of emptying without invasive catheterization.

Evaluation of the vomiting infant

This 12-month prospective study was undertaken to evaluate the cost, risk, and benefit of ultrasound followed by upper gastrointestinal series for the evaluation of the infant who vomits. Results suggest minimal morbidity from the upper gastrointestinal series, only a 33% reduction in the number of upper gastrointestinal series performed, and a 95% increase in cost if this imaging sequence is used. We conclude that the use of ultrasound for the initial evaluation of vomiting in infants substantially increases the cost with no meaningful decrease in morbidity and mortality.

Complicated appendiceal inflammatory disease in children: pylephlebitis and liver abscess

Five children with complicated appendiceal inflammatory disease are reported. They presented with nonspecific signs and symptoms, but three had liver abscess and two had inflammation of the portal vein. The inflamed portal vein may act as a conduit to the liver for bacteria, or it may become thrombosed and cause portal hypertension and hypersplenism. In one child, symptomatic portal hypertension developed 10 years after the initial disease. In children, an ultrasonic finding of a focal liver mass of low-to-mixed echogenicity or the presence of low-attenuation areas on computed tomographic scans should suggest the possibility of a hepatic abscess, and the radiologist has a major role in suggesting complicated inflammatory disease of the appendix as the cause. Similarly, when portal vein thrombosis or portal hypertension are found, the radiologist should consider complicated inflammatory disease of the appendix as the cause.

Optimal use of 99mtechnetium-glucoheptonate scintigraphy in the detection of pyelonephritic scarring in children: a preliminary report

Renal scintigraphy represents the optimal modality for the detection of renal scars. 99mTechnetium-glucoheptonate is rapidly accumulated by the kidney through glomerular filtration and active transport by renal tubular cells. This permits rapid visualization of the renal parenchyma in the early phase (1 to 3-minute images) and subsequent imaging of the collecting system and ureters. About 10 to 15 per cent of the injected activity remains in the kidney, labeling the cells of the proximal convoluted tubules (late phase or 1 to 2-hour images). The late phase has been used more commonly to assess renal parenchymal damage. Early and late phase glucoheptonate scanning was performed in 42 children as part of the evaluation of recurrent febrile urinary tract infections with or without a history of vesicoureteral reflux. Inter-observer reliability to interpret glucoheptonate scans was good (early, 83 per cent agreement and late, 93 per cent agreement). The ability of glucoheptonate scanning to detect renal scarring in children with febrile urinary tract infections was equivalent with the early or late phase of the study. In 6 patients renal scarring was detected on only the early phase scan and in 7 scarring was detected only in the late phase. Although the detection rates are equivalent the over-all detection of scarring is improved by using both phases. Therefore, the early phase of the glucoheptonate scan may be a valuable adjunct to conventional glucoheptonate scan methodology used for the detection of renal scarring in children with recurrent urinary tract infections.

Follow-up studies of multicystic dysplastic kidneys

Thirty cases of multicystic dysplastic kidney (MCDK) were diagnosed over 11 years. Nine patients underwent nephrectomy: three for increasing kidney size (classic MCDK) and six because of an inconclusive diagnosis (hydronephrotic MCDK). Of the remaining 21 patients, 19 were followed up for a mean of 33.5 months (range, 2-101 months). Follow-up ultrasound examinations revealed that 16 kidneys did not change in size, one decreased in size after cyst puncture, and two disappeared (one after cyst puncture). This series included one case of non-renin-producing hypertension that was controlled medically, one case of nephroblastomatosis found in the removed dysplastic kidney, and one case of pyelonephritis in the contralateral kidney. When the diagnosis of classic MCDK is made with imaging modalities, the lesion may not have to be removed unless there is growth of the mass during the 1st year of life. Nine percent of these lesions will disappear within the first 3 years of follow-up, and the authors recommend an even longer period of follow-up.

Ultrasound diagnosis of adrenal hemorrhage in meningococcemia

Two cases of adrenal hemorrhage in meningococcemia detected by ultrasound are reported. Antemortem detection of adrenal pathology may have important prognostic and therapeutic implications. The sonographic appearance may be echo-free, mixed, or echogenic. Abdominal ultrasound examination can be an effective non-invasive tool in diagnosing adrenal hemorrhage.

Update on pediatric chest imaging

Even in the high-technology medical imaging arena, the decision of how to first image pediatric chest disease is quite simple: by plain chest radiograph, including frontal and lateral views. The diagnosis can often be made or suggested on the basis of these films or with other basic imaging procedures, such as fluoroscopy or esophagram. From this point onward the decision how to proceed with further imaging such as ultrasound, computed tomography, nuclear medicine imaging, or magnetic resonance imaging, will depend on the probability of gaining further helpful information. Beginning with a concise differential diagnosis allows one to proceed in a logical manner through the diagnostic work-up in a time-effective and cost-effective manner. One must keep in mind that in some cases the diagnosis cannot be made radiologically and must be left to the pathologist. In these cases the work-up should end when no further progress is possible toward making the diagnosis. In the pediatric age group, one should always strive to limit the amount of unnecessary radiation exposure.

The renal lesions of tuberosclerosis (cysts and angiomyolipoma)--screening with sonography and computerized tomography

The two most common sonographic abnormalities in the kidneys of 23 tuberous sclerosis (TS) patients ranging in age from newborn to 30 years are angiomyolipomas (12/23) (AML) and renal cysts (10/23). These usually both occur in the same patient with only 9 cases (39%) having sonographically normal kidneys. Of the 14 affected patients, 2 had cysts without AML and 4 others had AML without cysts. The sonographic appearance of an AML varied from a large 6 cm solid mass with little increased echogenicity (1/12) to subtle small (4 mm) extremely echogenic regions in the periphery of the kidney (11/12). The sonographic appearance of the cysts were anechoic lesions varying in size from 2 mm to 2 cm with thin uniform posterior walls and posterior enhancement. Renal lesions are found more frequently with increasing age. Sonography is the preferred screening procedure for the renal lesions of T.S.

Ultrasonographic findings (CNS, thorax, abdomen) in infants undergoing extracorporeal oxygenation therapy

Extracorporeal membrane oxygenation (ECMO) has been performed on 45 neonates at the Children's Hospital of Michigan in a 39-month period. Ultrasound evaluation of these patients prior to and during ECMO therapy has demonstrated abnormalities in the central nervous system including intracranial hemorrhage (21), extra-axial fluid collections (5), and ventricular enlargement (2). Ultrasonic evaluation of the thoracic cavity in 12 infants revealed pleural fluid in 8. There were seven children with varying types of peritoneal fluid. Two children had visceral abnormalities - 1 with liver hemorrhage and 1 with hydronephrosis found prior to ECMO. Most of these findings could not have been diagnosed without ultrasound and may lead directly to alterations in clinical management. Ultrasound is an extension of physical examination which is important in hour-by-hour clinical care of patients on ECMO.

Endotracheal tubes in neonates: sonographic positioning

Twenty-one real-time sonographic determinations of endotracheal tube tip position were performed in 16 neonates. Findings were compared with those from simultaneously obtained chest radiographs. Relation of the tube tip to the aortic arch provided a reliable method of determination of appropriate position. Optimal tube tip position was seen when the tube tip was 1 cm above the arch.

Intracranial calcification in the infant and neonate: evaluation by sonography and CT

This study reports the sonographic and computed tomography (CT) findings in seven infants and neonates with intracranial calcifications and a spectrum of underlying disorders, including toxoplasmosis, cytomegalic inclusion disease, transverse/straight sinus thrombosis, and probable anoxia. Neurotropic infectious disease usually produced clumped or subependymal calcifications accompanied by sometimes bizarre ventricular configurations and prominent periventricular cystic encephalomalacia. Sonography failed to identify prospectively intracranial calcifications in two of the three patients without infection, although calcifications were visible in retrospect. Overall, CT provided optimum visualization of intracranial calcifications.

Renal transplants in children: long-term follow-up using sonography

Sonographic findings more than 1 year after transplantation for 16 children with renal transplants were reviewed to determine the appearance of the transplant on long-term follow-up and to correlate its sonographic appearance with its function. The appearance of the transplant varied considerably, and there was no association between renal function and renal volume, shape, parenchymal echogenicity, or central sinus echoes. Renal size and donor age were negatively associated. In children, a change in renal size greater than the usual 90%-130% of baseline volume seen in adults is a normal adaptation of the transplanted kidney to the recipient body size. Sonography was not useful for diagnosing chronic rejection or predicting function in the pediatric transplant patient.

Choanal atresia: precise CT evaluation

Computed tomography facilitates the diagnosis of children with choanal atresia. This modality defines the full anatomic abnormality of bony choanal atresia: medial bowing and thickening of the lateral wall of the nasal cavity, enlargement of the vomer, and fusion of these elements. Bony atresia patients can be clearly separated from those with membranous choanal atresia. In membranous atresia, the lateral wall of the nasal cavity is minimally affected and the vomer is normal. This precise anatomic evaluation aids in determining the surgical approach.

Simple renal cysts in infants

Two cases of renal cysts in infants less than one year of age are presented. In both instances percutaneous puncture of the cyst aided in establishing the diagnosis without the need for an operative procedure.

Normal values for ventricular size as determined by real time sonographic techniques

Seventy-three real time sonographic scans were performed through the anterior fontanelle of 67 infants between 28 and 48 weeks post-conception who had no evidence of intracranial disease. Several anatomical measurements were plotted against independent variables such as post-conception age, weight and head circumference at the time of the examination. All of the measurements increased as age, weight and head circumference increased. Ratios formed by dividing transventricular diameters by transcalvarial diameters at the two levels in the coronal plane and by dividing occipital mantle thickness by frontal mantle thickness in the parasagittal planes remained stable as all of the independent variables increased. In 88% of cases the occipital mantle could not be measured since the occipital horns of the lateral ventricles could not be identified. Since dilation of the ventricular system starts in the occipital horns of the lateral ventricles, non-visualization of this area is an important negative finding.

Renal manifestations of Kawasaki's disease

Renal sonographic evaluation of seven patients with mucocutaneous lymph node syndrome were performed and correlated with clinical and laboratory data either supporting or not supporting renal disease associated with this entity. Four of seven patients demonstrated significant elevations of the BUN, creatinine and/or significant proteinuria. These four patients had renal sonographic findings of increased cortical echogenicity, enlarged kidneys and enhanced corticomedullary differentiation. This complication of mucocutaneous lymph node syndrome has heretofore not been noted.

Renal transplant rejection: sonographic evaluation in children

The ability to detect renal rejection sonographically was studied in 42 pediatric renal transplant patients over a 33-month period. Sonography was not helpful in detecting rejection when the donor was less than five years of age. When the donor was over five years of age, a combination of sonographic findings allowed detection of rejection with a greater specificity than has been reported previously. The combination of three or more of the sonographic findings (increased renal volume 30% over the baseline value; enlarged, broadened, rectangular medullary pyramids [rays]; a reduction or absence of the central sinus echoes, and altered echogenicity in the renal parenchyma) indicated rejection with 97% specificity and 58% sensitivity. Radionuclide imaging with Tc-99m DTPA gave approximately the same sensitivity (60%) but was less specific (88%). By excluding rejection with the absence of the sonographic findings, it was possible to suggest acute tubular necrosis in some patients. It was also possible to detect the complications of renal transplantation, but sonography did not detect small ruptures of the kidney as a part of the rejection phenomenon.

Intracranial hemorrhage in the hypoxic-ischemic infant: ultrasound demonstration of unusual complications

Seven neonates (four preterm and three term) with severe hypoxic-ischemic parenchymal brain changes are presented to illustrate the kinds of parenchymal lesions demonstrable on ultrasound, to show the similarity of parenchymal lesions in preterm and term infants, and to correlate the severe neurologic deficits with the parenchymal changes. The lesions demonstrated are periventricular leukomalacia, large-vessel infarction, isolated parenchymal hemorrhage, multiple cystic encephalomalacia, and parenchymal atrophy. Parenchymal changes should be sought in such infants during any stage of their disease.

Effect of prophylactic phenobarbital on intraventricular hemorrhage in high-risk infants

Forty-two premature infants less than 24 hours of age, with normal admission echoencephalograms, were randomly assigned to control or phenobarbital treatment groups. Infants in the treated group received two loading doses of 10 mg/kg of phenobarbital 12 hours apart, followed by a maintenance dose of 2.5 mg/kg every 12 hours for 6 days. Serial echoencephalograms were obtained in both groups. The groups were comparable with regard to birth weight, gestational age, and potential risk factors for subependymal-intraventricular hemorrhage. Ten infants (48%) in each group developed hemorrhage. The hemorrhages in the phenobarbital-treated group were significantly less severe than those in the control group. The phenobarbital-treated infants who bled, however, were also significantly larger and more mature than control infants who bled. The results of this study indicate no effect of phenobarbital on the incidence of subependymal-intraventricular hemorrhage, but a possible beneficial effect on the severity of hemorrhage.