Power Doppler evaluation of joint effusions: investigation in a rabbit model.

OBJECTIVE: To study the power Doppler findings of septic arthritis and noninfectious synovitis in an animal model. MATERIALS AND METHODS: The right knees of 10 rabbits were inoculated with an aqueous suspension of Staphylococcus aureus. The right knees of 5 rabbits were injected with talc suspension. The right knees of 5 rabbits were injected with saline. All 20 left knees were injected with saline. Serial power Doppler images were obtained using constant-imaging parameters. Images were reviewed by blinded observers who assessed for increased power Doppler signal. RESULTS: All 10 knees inoculated with S. aureus developed septic arthritis. Each infected rabbit knee demonstrated increased signal on power Doppler on at least one examination, ranging from 1-6 days after inoculation. Only 23 of 45 examinations of infected knees were unequivocally positive by power Doppler on examinations performed 1 to 6 days after inoculation. No knee with talc synovitis demonstrated increased power Doppler signal. No control knee demonstrated increased power Doppler signal. CONCLUSION: Increased power Doppler signal may be seen with septic arthritis; however, its intensity and timing may vary from subject to subject. A normal power Doppler examination does not exclude septic arthritis.

MRI evaluation of infectious and non-infectious synovitis: preliminary studies in a rabbit model.

BACKGROUND: Literature on magnetic resonance imaging (MR) evaluation of inflammatory joint effusions is sparse. OBJECTIVE: To describe an animal model for studying infectious and non-infectious joint effusions with magnetic resonance imaging. MATERIALS AND METHODS: Ten rabbit knees with septic arthritis and four with talc synovitis were imaged with MR. Contralateral knees injected with saline served as controls. Fat saturation T2-weighted and gadolinium-enhanced T1-weighted images were assessed for joint effusion, and periarticular and adjacent intraosseous increased signal or enhancement. Each knee was cultured and underwent pathologic examination. RESULTS: Both Staphylococcus aureus and talc produced effusions in all knees. The degree of periarticular signal and enhancement was greater in infected knees than talc-injected knees. No abnormal enhancement was seen within bone. Pathologic examination showed a greater degree of inflammation and joint destruction in the infected knees, but no evidence of osteomyelitis. CONCLUSION: A greater degree of abnormal signal and enhancement seen on MR suggests a more vigorous inflammatory process, as seen with septic arthritis. In spite of advanced septic arthritis, no enhancement was evident within bone, suggesting that enhancement within bone is not an expected finding in isolated septic arthritis and should raise concern for osteomyelitis.

Ureaplasma urealyticum and chronic lung disease in very low birth weight infants during the exogenous surfactant era.

BACKGROUND: An association between recovery of Ureaplasma urealyticum from the respiratory tract of very low birth weight (VLBW) infants (< or =1500 g) and later chronic lung disease (CLD) was reported by several authors before the routine use of exogenous surfactant (SURF). We sought to assess whether this relation persists in the era of routine SURF. METHODS: We prospectively studied a cohort of 105 VLBW infants who required mechanical ventilation at < 12 h of age. Tracheal aspirates for U. urealyticum culture were obtained before administration of SURF or antibiotics. Clinicians were unaware of U. urealyticum status. Chest radiographs at 28 days were reviewed by a single pediatric radiologist, blinded to U. urealyticum status. Sample size was predetermined to detect a 30% increase in CLD among those with U. urealyticum recovery from tracheal culture (U. urealyticum-positive) with alpha <0.05 and beta <0.20. RESULTS: Of the study infants 22 were U. urealyticum-positive and 83 were U. urealyticum-negative. No differences were found between the groups for birth weight, gestational age, gender, inborn, antenatal or postnatal steroid use, SURF therapy, non-U. urealyticum infection, necrotizing enterocolitis, patent ductus arteriosus, intraventricular hemorrhage or cystic periventricular leukomalacia. At 28 days U. urealyticum-positive patients were significantly more likely to have CLD than U. urealyticum-negative [15 of 22 (68%) vs. 30 of 83 (36%); P < 0.02]. The U. urealyticum-positive patients also required significantly longer courses of supplemental oxygen and mechanical ventilation. No significant differences were found for CLD at 36 weeks postconception or duration of hospitalization, although type II error could not be excluded for these secondary endpoints. CONCLUSIONS: Respiratory U. urealyticum at or shortly after birth remains associated with CLD at 28 days despite routine use of SURF. Controlled trials of anti-Ureaplasma therapy in U. urealyticum-positive VLBWs as soon after birth as possible may determine whether CLD, duration of respiratory support and attendant costs can be decreased.

Successful treatment of neonatal arterial thromboses with recombinant tissue plasminogen activator.

Seven newborns were treated with recombinant tissue plasminogen activator for arterial thromboses. Complete lysis occurred in four of seven and partial in two of seven patients. Serious bleeding complications were observed in two of seven patients. This and published experience suggest that successful lysis with recombinant tissue plasminogen activator occurs in most patients and that hemorrhagic complications are unusual but are not.

Tracheal schwannoma presenting as status asthmaticus in a sixteen-year-old boy: airway considerations and removal with the CO2 laser.

A 16-year-old with clinical features of atypical asthma is presented, with a description of the workup leading to the diagnosis of an intratracheal mass. The mass was visualized with a flexible fiberoptic bronchoscope, then surgically removed through a rigid bronchoscope using a CO2 laser. We believe this is the first report of resection using this technique. A discussion of tracheal neurilemmomas (schwannoma) is included. This case reinforces the age-old adage that "not all that wheezes is asthma."

Pediatric hip effusions: evaluation with power Doppler sonography.

PURPOSE: To determine if power Doppler sonography allows differentiation of infectious from noninfectious hip effusions and thereby obviates joint aspiration. MATERIALS AND METHODS: Twenty-nine consecutive children (30 hips) with sonographically identified hip effusion were prospectively evaluated with power Doppler sonography. Both hips were evaluated in each patient by using identical imaging parameters and were then compared. Medical charts were reviewed to determine the eventual diagnosis. RESULTS: At power Doppler sonography, none of 16 patients with transient synovitis had increased flow in the affected hip compared with the contralateral normal hip. Of 11 patients with septic arthritis, one had asymmetric increased flow, and two others, in whom contralateral comparison images were limited, had probable increased flow. Three patients with miscellaneous diagnoses had symmetric normal flow. CONCLUSION: Because power Doppler sonograms did not depict increased flow in most patients with septic arthritis, normal flow on power Doppler sonograms does not allow exclusion of septic arthritis and should not preclude aspiration when clinically warranted.

Vesicoureteral reflux in older children: concordance of US and voiding cystourethrographic findings.

PURPOSE: To determine if a negative renal sonogram is reliably predictive of the absence of vesicoureteral reflux at voiding cystourethrography (VCUG) in children aged 5 years or older. MATERIALS AND METHODS: Imaging studies in 70 children aged 5 years or older who underwent renal ultrasound (US) and VCUG on the same day were reviewed. These children had initially undergone evaluation because of a urinary tract infection. RESULTS: Five of 70 children had abnormal sonograms; two (40%) of the five had reflux at VCUG. One had mild pelvicalyceal dilatation, and one had a small kidney. The other three (without reflux) had a pelvic kidney, a calyceal diverticulum, or a renal stone. Of 65 children with a negative sonogram, 19 (29%) had reflux at VCUG; 46 (71%) did not. Altogether, of the 70 children, 21 had reflux, 19 (90%) of whom had no sonographic abnormality. CONCLUSION: Children with abnormal screening renal sonograms often have vesicoureteral reflux, but a normal sonogram does not reliably exclude the condition even in children aged 5 years or older. Therefore, VCUG must be performed even in older children, regardless of US findings, if clinical decisions are influenced by documentation of the presence of VUR.

Neonates with congenital diaphragmatic hernia: radiographic findings during partial liquid ventilation.

PURPOSE: To determine the serial radiographic appearance of the lungs of neonates who underwent partial liquid ventilation with perflubron because of congenital diaphragmatic hernia (CDH) or primary pulmonary hypertension. MATERIALS AND METHODS: Bedside anteroposterior (AP) and lateral chest radiographs (n = 235) were scored for percentage of lung opacification by perflubron during partial liquid ventilation (PLV) and extracorporeal membrane oxygenation (ECMO). Five neonates participated in the study; four had CDH, and one had primary pulmonary hypertension. RESULTS: The lungs were opacified nearly completely after each dose of perflubron. The degree of opacification was the same on 117 of 169 (69%) AP radiographs and within one point on another 40 (24%). A gravity-dependent distribution was shown on 58 of 66 (88%) lateral radiographs. A minimal amount of perflubron remained in the lungs after 5.2 days. A hypoplastic bronchus and ipsilateral lung were manifest in all four of the patients with CDH after the airway and lung were filled with radiopaque perflubron. CONCLUSION: Lungs filled with perflubron were opacified to a similar degree in a gravity-dependent distribution. Evaporation of perflubron from the lungs of neonates is relatively rapid. The size of the ipsilateral bronchus and lung may be estimated by comparison of radiographs taken before and after the lungs were filled with perflubron.

Ileocolic intussusception presenting with bilious vomiting due to extrinsic duodenal obstruction.

We present a case of a child presenting with bilious vomiting due to extrinsic duodenal obstruction by an ileocolic intussusception. The clinical presentation, radiographic findings, and use of sonography are discussed.

Significance of spina bifida occulta in children with diurnal enuresis.

We reviewed retrospectively 456 patients with diurnal enuresis to determine the relationship between spina bifida occulta and attainment of continence. Of these patients 127 had undergone x-rays of the spine and 48 children (48%) had spina bifida occulta. The clinical course of these patients was compared to 79 enuretic children with normal spine films. All patients were initially treated with a timed voiding program and 28 with persistent enuresis were given anticholinergic medication. Findings on urodynamic studies were similar for both groups. Uninhibited bladder contractions were found in the majority of patients and 2 children in each group had hypertonic filling curves. Of 10 children with spina bifida occulta magnetic resonance imaging or ultrasound of the spine revealed lipoma and tethering of the cord in 1. Mean followup for both groups was 3 years. The outcome for enuretic children with spina bifida occulta was comparable to those with normal spine x-rays. The majority of patients had resolution of the enuresis with conservative management. Spinal ultrasound or magnetic resonance imaging may be warranted in those children with abnormal neurological findings on examination or hypertonic filling curves, or those who fail to respond to medical treatment. However, neurosurgical intervention to achieve continence appears necessary in only a small percentage of enuretic children with spina bifida occulta.

Effect of furosemide and intravenous normal saline fluid load upon the renal resistive index in nonobstructed kidneys in children.

Recent literature has shown that relative to baseline the renal resistive index remains unchanged in nonobstructed kidneys and increases in obstructed kidneys after administration of furosemide. To our knowledge the effect upon the renal resistive index of furosemide administered in conjunction with intravenous normal saline fluid load has not been reported. We evaluated the renal resistive index in 13 nonobstructed kidneys in 8 children 6 to 18 years old before and after furosemide and intravenous normal saline fluid load. The mean resistive index decreased from baseline (mean decrease was 0.06 +/- 0.06 standard deviation), with the observation of a resistive index decrease significant to p < 0.005). It appears likely that the combination of an intravenous normal saline fluid load and furosemide caused the resistive index decrease, since a decrease was not observed with furosemide alone; however, these results cannot exclude the possibility that the resistive index decrease was due to the intravenous normal saline fluid load alone. Nonetheless, these data are important since they may provide the foundation for the development of a pharmacologically challenged Doppler sonographic examination using furosemide and intravenous normal saline fluid load to evaluate better potentially obstructed kidneys.

Intravesical oxybutinin chloride in children with intermittent catheterization: sonographic findings.

The sonographic findings in the bladder are presented in four children with myelomeningocele and neurogenic dysfunction of the bladder, who were treated with intermittent self-catheterization and intravesical oxybutinin chloride. All were referred for routine sonography of the urinary tract. Each had infused a crushed tablet of oxybutinin chloride intravesically 30-120 min before the examination. In two children, brightly echogenic, non-shadowing particles were suspended in the bladder urine. In one of these, the particles swirled giving the impression of a "snowstorm"; in the other, most of the particles gradually settled forming an irregular clump on the bladder base. In the remaining two children, the urine appeared diffusely hazy with innumerable tiny particles giving the impression of a fine mist filling the bladder. The sonographic appearance of the urine in the bladder after intravesical instillation of crushed tablets can be dramatic and can simulate pus, blood, fungus, or other debris in the bladder lumen. In the absence of clinical symptoms or hematuria, a history of recent infusion of medication into the bladder should be sought.

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.

Renal sonography is not a reliable screening examination for vesicoureteral reflux.

A retrospective analysis of 493 infants and children was performed to determine the reliability of renal sonography for identifying vesicoureteral reflux. Sonography was done in all cases within 8 hours of a voiding cystourethrogram. Vesicoureteral reflux was documented in 272 of 986 kidneys on voiding cystourethrography and there were 201 refluxing kidneys with normal ultrasound (25 with grade I reflux, 119 with grade II, 50 with grade III, 6 with grade IV and 1 with grade V). In 71 of the refluxing kidneys the ultrasound was abnormal due to pelvicaliceal dilatation in 45, a duplication anomaly in 6 and renal fossae abnormality in 20. Of the kidneys with vesicoureteral reflux 74% were sonographically normal. Sonography was not sufficiently sensitive or specific for detecting vesicoureteral reflux, since 28% of the missed refluxing kidneys had grade III or higher reflux.

The conus medullaris: normal US findings throughout childhood.

A prospective ultrasound (US) study of children without neurologic or spinal problems or midline cutaneous abnormalities on the back was performed to determine the level of the conus medullaris in healthy children. The tip of the conus was identified in sagittal and transverse planes, and a radiopaque bead was placed on the skin to mark the location of the tip. Findings at subsequent radiography confirmed the vertebral level. A total of 161 children, aged 4 days to 13 years 5 months (mean, 3 years 7 months; median, 3 years 1 month), composed the study population. Conus levels in these healthy children varied from the level of T10-11 interspace to the superior aspect of the L-3 vertebra. However, in only two children were the conus levels below the middle portion of L-2. Estimations of vertebral levels of the conus based on the US scan alone were within one vertebral level of the level determined at radiography in 145 of 161 (90%) cases. Palpable landmarks, the tip of the lowest rib and the iliac crest, corresponded to the level of the L-2 and L-5 vertebrae, respectively. The conus medullaris can be located at US in most children, even beyond infancy. The normal levels are constant throughout childhood.

Cranial sonography and neurological examination at term and motor performance through 19 months of age.

This study examined the role of cranial sonography and neurological examination in the prediction of developmental progress during the first 19 months of life in extremely preterm infants. Forty-seven infants with mean birth weight 993 +/- 197 g and gestational age 27.9 +/- 1.9 weeks were studied. Each infant was classified as normal, suspect, or abnormal using cranial sonography and a structured neurological examination. Developmental outcome was assessed using the Infant Neurological International Battery (INFANIB) at 4, 8, and 14 months and the Rockford Infant Developmental Evaluation Skills (RIDES) at 19 months. Sonographic classification was the best predictor of outcome through 14 months, F(2.72) = 12.4, p < .001. The neurological examination predicted performance only at 4 months. No infant classified as normal on both examinations was abnormal on follow-up. Infants with suspect or abnormal neurological examinations had normal outcomes if their sonographic findings were normal.

MIBG detection of hepatic neuroblastoma: correlation with CT, US and surgical findings.

Metaiodobenzylguanidine (MIBG) imaging is used in the diagnosis, staging and follow-up of virtually every case of neuroblastoma seen at our institution. Normal sites of MIBG uptake include the liver and therefore difficulties have been predicted and encountered in the diagnosis of hepatic neuroblastoma due to inability to separate abnormally increased tracer deposition from normal hepatic activity. We reviewed every MIBG (I123 and I131) study performed at our pediatric hospital over a 4 year period encompassing 88 patients, 67 of whom had biopsy proven neuroblastoma. Hepatic findings onMIBG studies were compared with concurrent abdominal CT and US studies in all 67 patients. The clinical records of all patients with abnormal MIBG scans or abnormal CT or US studies of the liver were also reviewed. Eight patients were found to have abnormal liver findings on one or more imaging studies (MIBG, CT, or US). There were 3 true positive MIBG studies, one of which was an early study in a patient who later went on to have one of the false positive studies. Two patients had false positive MIBG scans for liver neuroblastoma. MIBG failed to detect liver involvement in 4 patients.

Age dependency of the renal resistive index in healthy children.

It has recently been suggested that the resistive index (RI) in native kidneys of healthy children is age dependent; however, this relationship has not been completely defined or explained. In 110 kidneys in 71 healthy children aged newborn to 11 years, RIs were determined from peripheral sites (presumed to be arcuate, cortical, or distal interlobar arteries). The authors found the normal renal RI (the mean RI in each kidney) to be age dependent. The renal RI in children is commonly elevated above the upper normal limit in adults (0.70) in the 1st year of life, and the overall trend shows a decrease with age. From 4 years on, the likelihood is low (2% probability) that the RI is above 0.70. Variability of the renal RI from individual to individual was most marked in the first 6 months of life, with 51% (19 of 37) of these kidneys having an RI that would be considered abnormal by adult standards. It is concluded that the normal renal RI is age dependent, with an overall decreasing trend with increasing age. This age dependency of the renal RI and, hence, of the renal vascular resistance might be dependent on levels of active renin, as the maturational profile of the renal RI more closely parallels that of active renin than those of other renal functional parameters.