Symptomatic spinal epidural collections after lumbar puncture in children.

BACKGROUND AND PURPOSE: Complications from lumbar puncture (LP) include headache; mild puncture-site pain; and, rarely, subdural, epidural, or subarachnoid hemorrhage. In infants, asymptomatic leakage of CSF documented with ultrasound is common. We report the MR imaging findings and clinical course of 25 symptomatic patients with spinal epidural collections after LP. MATERIALS AND METHODS: MR imaging and clinical records of 25 children with new symptoms following LP were retrospectively reviewed. RESULTS: All patients had abnormal dorsal spinal epidural collections. Signal-intensity characteristics of the collections were most commonly isointense to CSF on all pulse sequences. Significant anterior displacement of the dura with effacement of the subarachnoid space was frequently noted. All patients had fluid surrounding small foci of epidural fat, elevating them from their native interspinous fossa, resulting in a "floating" appearance. Eighteen collections involved the thoracic and lumbar spine; 4 involved the thoracic, lumbar, and sacral spine; 2 extended from the lumbar to the cervical level; and 1 was isolated to the lumbar spine. Five patients had follow-up MR imaging showing complete resolution of collections. The size of the collections was not directly related to the number of puncture attempts. Clinical symptoms resolved with time in all patients with conservative management. CONCLUSION: Symptomatic epidural fluid collections after LP are often extensive and may compromise the thecal sac. These collections are not usually the result of a difficult LP and have signal intensity characteristics most consistent with CSF leak rather than hemorrhage. Signs and symptoms typically resolve with time, without treatment and with no serious sequelae.

Lingual hamartoma in an infant: CT and MR imaging.

Lingual hamartoma is a rare tongue mass, primarily diagnosed in childhood. In most cases in the literature, the masses were surgically removed without preoperative imaging. There are only 3 cases reported in the clinical literature that describe preoperative imaging findings. We report the clinical and imaging findings in an infant with lingual hamartoma and review the literature.

Diagnostic and interventional ultrasound of the pediatric spine.

Ultrasound is useful as a diagnostic tool in the evaluation of the pediatric spine, and can also help guide procedures in the interventional radiology suite or the operating room. This pictorial exhibit will display examples of diagnostic and interventional uses of ultrasound with respect to the pediatric spine.

Langerhans histiocytosis of temporal bone: role of magnetic resonance imaging.

Langerhans cell histiocytosis (LCH) may involve nearly every organ of the body. In children, head and neck involvement has been reported in as many as 82% of patients. Sites of head and neck involvement include skull, temporal bone, orbit, mandible, maxilla and cervical nodes. In addition, patients may have coexisting central nervous system (CNS) involvement adjacent to, or remote from, osseous lesions. Magnetic resonance imaging (MRI) of the temporal bone in patients with LCH is ideal for evaluating the extracranial extent of the soft-tissue mass and is complementary to computed tomography (CT) in the assessment of osseous erosion. MRI is superb in the evaluation of intracranial extension, usually into the middle cranial fossa, and of patency of adjacent vascular structures. It is the imaging modality of choice to evaluate patients with suspected CNS involvement of LCH, which includes lesions of the infundibulum, cerebrum, cerebellum, and extra-axial spaces.

Vesicoureteral reflux: subpopulations of patients defined by clinical variables.

BACKGROUND: The first imaging evaluation of the child with urinary tract infection (UTI) is often the same for all children, regardless of the child's clinical presentation. However, this approach is simplistic and ignores considerable differences in the frequency of abnormal pathophysiology in different subpopulations of children with UTI. OBJECTIVE: Six clinical variables are evaluated as predictors of vesicoureteral reflux (VUR) in a large series of girls with UTI. MATERIALS AND METHODS: Data were collected from a consecutive series of 919 girls undergoing a first imaging evaluation for UTI. Six input variables were used: age, maximum body temperature (T(max)), number of UTIs, hospitalization, family history of childhood UTI, and rapidity of response to antibiotic therapy. The dependent variable was VUR. Data were enumerated and analyzed by logistic regression and the chi-square test. RESULTS: VUR was present in 28.8 %. The percentage with VUR varied from 56.1 % for age < 6 months and T(max) L 38.5 degrees C to 13.0 % for age L 10 years and T(max) < 38.5 degrees C. The frequency of VUR was significantly lower in girls with T(max) < 38.5 degrees C in most age groups. Logistic regression demonstrated, when all clinical variables were taken together, that only age and T(max) were independent predictors of VUR. CONCLUSIONS: Girls with UTI should not be considered to be a homogeneous group. The frequency of VUR is related to T(max) and inversely to age. Data about these subpopulations should be used in deciding which girls should undergo cystography.

Imaging extracranial masses of the pediatric head and neck.

This article focuses on the many benign and malignant extracranial head and neck neoplasms that occur in the pediatric patient. Discussion emphasizes the imaging characteristics of lesions by location: the orbit, the sinonasal cavity, the nasopharynx, the face and jaw, and the neck.

Cyclic cystography: diagnostic yield in selected pediatric populations.

PURPOSE: To test the hypothesis that the diagnostic yield of cyclic cystography is related to the prevalence of vesicoureteral reflux (VUR) in the population being evaluated. MATERIALS AND METHODS: Two groups of children were examined prospectively: 124 with severe urinary tract infection, defined as patient hospitalization or a maximum temperature greater than 39.5 degrees C, and 135 with previously diagnosed VUR. Nuclear cystography was performed in 249 patients, and fluoroscopic cystography was performed in 10. If VUR was not seen during the first cycle of bladder filling and voiding, a second cycle was performed. RESULTS: VUR was present during cycle 1 in 40 (32%) of 124 patients with severe urinary tract infection and 90 (67%) of 135 children in the VUR follow-up group (P < .001). VUR was demonstrated during cycle 2 in seven (9%) of 76 of the severe urinary tract infection group and eight (24%) of 34 of the VUR follow-up group (P = .045). Of 15 patients with VUR during cycle 2, two had grade III VUR and 13 had grade I or II VUR. CONCLUSION: The second cycle of cyclic cystography has a higher diagnostic yield in patients undergoing VUR follow-up than in patients with severe urinary tract infection. The decision to perform a second cycle of bladder filling and voiding should take into account the pretest probability of VUR in the child being examined.

Correlation between computed tomography and surgical findings in retropharyngeal inflammatory processes in children.

Retropharyngeal abscess (RPA) in children is a potentially life-threatening process which often requires immediate surgical intervention. Contrast enhanced computed tomography (CT) is utilized frequently to determine abscess versus cellulitis/phlegmon and aids in determining cases needing surgical drainage. The purpose of this retrospective study was to determine the accuracy of CT in distinguishing retropharyngeal abscess from cellulitis in children. The medical records of 32 children from 1989 to 1997 suspected of having a retropharyngeal abscess were reviewed. All patients included in the study underwent a CT scan as well as surgical exploration within 48 h of the scan. Two patients required two surgical procedures (n = 34). A comparison between CT results and operative findings was made to determine the accuracy of CT imaging in confirming the presence of RPA versus cellulitis. Suspected diagnosis of abscess or cellulitis/phlegmon on CT was confirmed at surgery in 25 of 34 cases (73.5%). The false positive rate of CT scan was 11.8% (4/34), while the false negative rate was 14.7% (5/34). Based on our results, CT is accurate in differentiating abscess from cellulitis in 73.5% of cases. Clinical findings, as well as radiologic findings, must be considered together prior to surgical drainage of a suspected retropharyngeal abscess in children.

Presentation and diagnosis of unilateral maxillary swelling in children.

Facial asymmetry secondary to pathologic processes involving the maxillary sinus and its surrounding structures presents a challenge for the clinician. An organized approach to evaluate these patients is essential in order to differentiate inflammatory sinus pathology from disease processes primarily involving the surrounding maxilla, parotid gland, orbital contents, and dental structures. In addition to a thorough history and physical examination, appropriate imaging studies must be obtained to localize the pathologic processes and develop a meaningful differential diagnosis. Once this is accomplished, specific treatment modalities can be developed. Representative cases will be presented to illustrate this organized approach to unilateral maxillary swelling, including soft tissue and osseous masses, fibro-osseous lesions, osseous cysts and inflammatory lesions.

Inhalation of substance P and thiorphan: acute toxicity and effects on respiration in conscious guinea pigs.

Substance P is a tachykinin and a biologically active neuropeptide. The peptide produces salivation, neuronal excitation, vasodilatation, increased vascular permeability and contraction of smooth muscles in the respiratory tract. The study was designed to evaluate the acute effects in guinea pigs of inhaled aerosolized Substance P (SP). Apart from the acute toxic effect of the peptide, the distribution in different organs was also investigated. The acute inhalation toxicity of SP (LC50, 15 min) when co-administrated with the neutral endopeptidase inhibitor thiorphan was 368 microg m(-3). The peptide caused an increase in respiratory rate proceeding a decrease in tidal volume. As the exposure proceeded, a decrease in both respiratory rate and further decreases in tidal volume were observed until either the animal died or the exposure was terminated. The decreases in respiratory rate and tidal volume were probably due to bronchoconstriction caused by SP. Eighteen per cent of the inhaled amount of radioactive SP was retained in the body, and the highest concentrations of radioactivity were found in the kidney, lung and liver. Substance P in combination with thiorphan administered as an aerosol is extremely toxic and highly potent. Exposure to the substance at extremely low air concentrations may result in incapacitation in humans.

Magnetic resonance imaging of the pediatric head and neck.

Although the bulk of pediatric head and neck lesions are adequately evaluated by computed tomography (CT) alone, magnetic resonance imaging (MRI) provides valuable additional information in those lesions that are difficult to resolve on CT, and it is almost essential for assessment of possible intracranial extension of disease. The ability of MRI to show intrinsic characteristics of mass lesions can help direct therapeutic decisions. It should be utilized early in the imaging evaluation of most vascular lesions, including juvenile nasal angiofibroma and vascular malformations, in suspected neurogenic tumors, and as an adjunct in those cases where CT does not adequately demonstrate the extent or true nature of a lesion.

Air bag-related deaths and serious injuries in children: injury patterns and imaging findings.

BACKGROUND AND PURPOSE: As of November 1, 1997, automotive air-bag deployments occurring in low-speed collisions had resulted in the deaths of 49 children and in the serious injuries of 19 children in the United States. The purpose of this study was to investigate the patterns of injury occurring in this new mechanism of pediatric trauma. METHODS: In search of common patterns of injury, three pediatric radiologists retrospectively evaluated the available autopsy and imaging studies in 11 such cases not previously reported in the medical literature, in addition to three published case studies. RESULTS: The cause of death or serious injury in every case was the direct result of neurologic injury. Injury patterns differed according to the child's age and type of restraint used at the time of collision. Crush injury to the skull predominated in infant victims traveling in rear-facing child safety seats, and both cranial and cervical spine trauma occurred in older children traveling restrained, improperly restrained, or unrestrained in the vehicle's front passenger seat. CONCLUSION: Air-bag systems pose a potentially fatal threat to the front-seat child passenger. This is directly related to the biomechanics at impact placing the child closer to the deploying air bag. An understanding of the biomechanics provides the radiologist insight into the two types of injury patterns observed.

Central nervous system relapse of treated stage IV neuroblastoma.

Neuroblastoma is the most common extracranial solid tumor in pediatrics. The long-term survival of patients with advanced-stage neuroblastoma has remarkably improved secondary to aggressive treatment protocols including autologous bone marrow transplant (BMT). As a result, a different natural history of this disease is being reported with unusual, late manifestations. The central nervous system (CNS), once a rare site of disease, is being involved with increasing frequency. Appropriate neuroimaging in these patients is important. Two cases of patients with treated stage IV neuroblastoma who developed isolated CNS metastases are presented. The proposed pathogenesis and neuroradiologic manifestations of this complication are reviewed.

Phosphorylation of cbl after stimulation of Nb2 cells with prolactin and its association with phosphatidylinositol 3-kinase.

Stimulation of Nb2 cells with PRL results in the rapid phosphorylation of a 120-kDa protein identified as the adapter protein cbl on tyrosine residues. Maximal phosphorylation of cbl occurs at 20 min after PRL stimulation and declines thereafter. Stimulation with as little as 5 nM PRL resulted in the phosphorylation of cbl; increasing the concentration of PRL to 100 nM had only a minimal effect upon the phosphorylation of cbl. The cbl protein appears to be constitutively associated with grb2 and the p85 subunit of phosphatidylinositol 3-kinase (PI 3-kinase). The constitutive association of cbl with the p85 subunit of PI 3-kinase was observed in Nb2 cells as well as in 32Dcl3 cells transfected with either the rat Nb2 (intermediate) form of the PRL receptor or the long form of the human PRL receptor. A glutathione S-transferase fusion protein encoding the SH3 domain of the p85 subunit of PI 3-kinase bound to cbl in lysates of both unstimulated and PRL-stimulated Nb2 cells; however, neither of the SH2 domains of p85 bound to cbl under the same conditions. PRL stimulation increased the cbl-associated PI kinase activity. The majority of PI kinase activity appeared to be cbl-associated after PRL stimulation. These results suggest that cbl may function as an adapter protein in PRL-mediated signaling events and regulate activation of PI 3-kinase. Our model suggests that the p85 subunit of PI 3-kinase is constitutively associated with cbl through binding of the p85 SH3 domain to a proline-rich sequence in cbl. After the tyrosine phosphorylation of cbl, an SH2 domain(s) of p85 binds to a specific phosphorylation site(s) in cbl, leading to the activation of PI 3-kinase.

Safety and efficacy of sedation in children using a structured sedation program.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of sedating pediatric outpatients in a radiology department using a structured sedation program modeled after the guidelines of the American Academy of Pediatrics. MATERIALS AND METHODS: Medical records of 6006 pediatric outpatients who underwent sedation for imaging studies under the guidelines of a structured sedation program were retrospectively reviewed for safety and efficacy of sedation, complications related to sedation, and rate of successful sedation. RESULTS: No cases of cardiovascular or respiratory arrest or fatalities occurred. Four children who required overnight hospitalization because of CNS depression had no sequelae. Forty-eight patients experienced transient respiratory depression that proved responsive to supplemental oxygen. Delayed complications were found in 29 children, none of whom required hospitalization. The rate of sedation failure was approximately 1%. CONCLUSION: Sedation of children can be done in a safe and highly efficacious manner in a hospital radiology department using a structured sedation program modeled after the guidelines of the American Academy of Pediatrics.

Congenital epulis.

Congenital epulis of the newborn is a rare gingival tumor that occurs along the alveolar ridge. We report the prenatal sonographic and postnatal MR imaging findings in an infant with maxillary and mandibular congenital epulides.

Phosphorylation of Cbl following stimulation with interleukin-3 and its association with Grb2, Fyn, and phosphatidylinositol 3-kinase.

We have demonstrated that a 120-kDa protein, identified as Cbl, becomes rapidly phosphorylated on tyrosine residues following stimulation of factor-dependent cells with interleukin-3 (IL-3). Little or no phosphorylation of Cbl was observed in the absence of IL-3 stimulation and phosphorylation is maximal by 20-30 min after IL-3 stimulation. Association of Cbl with Grb2 was noted in unstimulated cells, and the amount of Cbl associated with Grb2 increased following IL-3 stimulation. The p85 subunit of phosphatidylinositol 3-kinase was constitutively associated with Cbl. Approximately 10% of the PI kinase activity present in anti-phosphotyrosine immunoprecipitates was present in anti-Cbl immunoprecipitates of IL-3-stimulated cells. The constitutive association of Cbl with Fyn was also observed. Cbl was observed to bind to bacterial fusion proteins encoding the unique, SH3, and SH2 domains of Fyn, Hck, and Lyn. The SH2 domain of Fyn alone was able to bind Cbl to nearly the same extent as did the fusion protein encoding the unique, SH3, and SH2 domains. This was not the case for the SH2 domain of Hck, however, as binding of the Hck fusion protein to Cbl appeared to require multiple domains. The binding of the fusion proteins to Cbl occurred regardless of whether Cbl was tyrosine-phosphorylated or not, and the binding could not be disrupted by the addition of 30 mM free phosphotyrosine. These data suggest the unexpected conclusion that the Fyn SH2 domain may bind to Cbl in a phosphotyrosine-independent manner.

Congenital malformations causing skull base changes.

Recent advances in imaging have enabled both the clinician and radiologist to better understand the therapeutic implications of congenital anomalies involving the skull base. Critical to this understanding is a full knowledge of normal embryologic development, anatomic detail, and clinical manifestations in the wide variety of congenital malformations involving the skull base. This review focuses on individual malformations in terms of their pathophysiology and their imaging findings of critical importance.