Intussusception: hospital size and risk of surgery.

OBJECTIVE: To determine whether the risk of operative management of children with intussusception varies by hospital pediatric caseload. DESIGN: A cohort of all children with intussusception in Washington State from 1987 through 1996. SETTING: All hospitals in Washington State. METHODS: Five hundred seventy children with a hospital discharge diagnosis of intussusception were identified. Sixty-two were excluded because of missing data. Procedure codes for operative management and radiologic management were also identified. RESULTS: Fifty-three percent of the children had operative reduction and 20% had resection of bowel. Children with operative reduction did not differ from those with nonoperative care by median age or gender; however, children with operative care were significantly more likely to receive care in hospitals with smaller pediatric caseloads and to have a coexisting condition associated with intussusception. Sixty-four percent of children who received care in a large children's hospital had nonoperative reduction, compared with 36% of children who received care in hospitals with 0 to 3000 annual pediatric admissions and 24% of children who had care in hospitals with 3000 to 10 000 annual pediatric admissions. Median length of stay and charges were significantly less in the large children's hospital, compared with other centers. CONCLUSIONS: Children who received care for intussusception in a large children's hospital had decreased risk of operative care, shorter length of stay, and lower hospital charges compared with children who received care in hospitals with smaller pediatric caseloads.

Intracranial resistive index (RI) values in normal term infants during the first day of life.

PURPOSE: The purpose of this study was to determine normal resistive index (RI) values for term neonates during the first day of life as part of an ongoing prospective study of RI values in term infants with perinatal asphyxia. MATERIALS AND METHODS: Forty normal term neonates underwent cranial sonography and Doppler during the first 24 h after birth. Transfontanelle Doppler was performed of the internal carotid, anterior cerebral, and middle cerebral arteries bilaterally. In addition, transtemporal Doppler was performed of the middle cerebral arteries bilaterally. Mean and median RI values were calculated in all vessels interrogated. The transfontanelle and transtemporal middle cerebral artery measurements were compared using paired t-tests. RESULTS: The overall mean RI of all interrogated vessels was 0.726 with a standard deviation of 0.057. The mean RI value in the middle cerebral arteries was not significantly different with the two different measurement techniques. CONCLUSION: Normal intracranial RI values for a term infant in the first day of life were calculated for comparison with RI values in term infants with perinatal asphyxia.

Transcranial Doppler in the newborn with asphyxia.

Transcranial Doppler of infants suffering hypoxia-ischemia may demonstrate high diastolic flow in the early postasphyxial and hyperemic phase of the insult. This increase in diastolic flow decreases the resistive index. The use of the resistive index to quickly assess the infant at the bedside may become more important with the advent of newer neuroprotective strategies.

Intracranial aneurysms in infants and children.

BACKGROUND: The diagnosis and imaging of pediatric aneurysms has changed since the advent of MR and MRA. OBJECTIVE: To update the literature on pediatric aneurysms and better define the appropriate work-up of childhood aneurysms in 1997. MATERIALS AND METHODS: Retrospective review of 21 children (12 boys, 9 girls) with 25 aneurysms from three institutions over a 20-year period was performed. Imaging studies were mixed and included CT (19 patients), MR (11 patients), MRA (6 patients) and angiography (18 patients). RESULTS: Eighteen of 25 aneurysms were congenital saccular, 6 were mycotic, and 1 was post-traumatic. Of these, 44 % were in the posterior circulation. Nine aneurysms arose from distal arterial branches. Forty percent were large (between 1-2.5 cm) and 16 % were giant (> 2.5 cm). CT and MR showed hemorrhage, and frequently revealed the aneurysms as a focal mass with or without enhancement and flow void. Six children had MRA which revealed aneurysms in four patients. All patients with MRA had corresponding conventional angiography. CONCLUSION: Characteristics of pediatric aneurysms include diversity of type, increased incidence in the posterior fossa, peripheral location, and large size. CT, MR and MRA are useful in the diagnosis with conventional angiography essential for preoperative planning.

Reconversion of bone marrow in Gaucher disease treated with enzyme therapy documented by MR.

BACKGROUND: Skeletal complications are responsible for significant morbidity in Gaucher patients. Plain radiographs have been unreliable in assessing bone marrow infiltration and activity. A way to assess bone marrow improvement is needed during enzyme therapy. OBJECTIVE: The purpose of this paper is to assess the usefulness of MR in following improvement of abnormal bone marrow in Gaucher patients on enzyme therapy. MATERIALS AND METHODS: Three patients aged 2, 7, and 24 years underwent serial MR scans of the lower extremities before and during treatment with Alglucerase (two patients) and Imiglucerase (one patient). T1-weighted, T2-weighted, STIR and FSE T2-weighted images were utilized. Two patients were imaged after 16 months of therapy, and one patient was imaged after 6 months of therapy. RESULTS: All patients had improvement in marrow signal consistent with partial reconversion to fatty marrow during treatment. The findings were more marked after prolonged therapy. T1-weighted images demonstrated findings most clearly. CONCLUSION: MR consistently showed improvement in marrow signal in Gaucher patients on enzyme therapy. As smaller doses of enzyme therapy are the trend, MR can be utilized to determine if therapy is effecting a change in the bone marrow.

Transcranial Doppler, MRA, and MRI as a screening examination for cerebrovascular disease in patients with sickle cell anemia: an 8-year study.

OBJECTIVE: The authors previously reported five transcranial Doppler ultrasonography (TCD) findings as significant in detecting clinical cerebrovascular disease in a 4-year study in patients with sickle cell disease. This is a follow-up to evaluate the validity of the original findings over another 4-year period during which the study population doubled. A clinical follow-up of the original asymptomatic sickle cell patients with positive TCD, MRA, and MRI was also made. MATERIALS AND METHODS: Over an 8-year period TCD, MRI, and MRA were prospectively performed in 90 sickle cell patients who were clinically asymptomatic for stroke and in 27 sickle cell patients with clinical stroke. RESULTS: Of the 4 out of original 46 control patients in 1992 who had positive MRA and TCD, 3 have subsequently had clinical stroke. None of the 9 original patients with positive TCD and positive MRI but negative MRA have developed stroke. All five original TCD indicators of disease were still significant (P < 0.05) for detecting clinical disease: maximum velocity in ophthalmic artery (OA) > 35 cm/s, mean velocity in middle cerebral artery (MCA) > 170 cm/s, resistive index (RI) in OA < 50, velocity in OA greater than in MCA, and velocity in posterior cerebral (PCA), vertebral, or basilar arteries greater than in MCA. An RI of < 60 in the DA was also now found to be significant [corrected]. Four additional factors were also significant: turbulence, PCA or ACA without MCA, RI < 30, and maximum velocity in MCA > 200 cm/s. CONCLUSION: Positive MRA with a positive TCD in an asymptomatic patient in long-term follow-up suggests a trend for developing clinical stroke. A 4- to 8-year follow-up of nine patients with positive TCD, positive MRI, but not positive MRA did not show development of clinical stroke. Nine Doppler findings are significant in screening for clinically symptomatic vascular disease in sickle cell patients. It is recommended that children with sickle cell disease be screened for cerebrovascular disease with TCD. If one or two indicators of abnormality are present, MRA is recommended. If the MRA is positive, the patient may be considered for transfusion therapy or other treatment for prevention of stroke.

Disappearing enhancing brain lesion in a child with neurofibromatosis type I.

Neurofibromatosis type 1 (NF1) in children can produce a variety of parenchymal signal abnormalities on cranial MR. Areas of abnormal signal in these patients may represent regions of disordered myelination, "hamartomatous" change or frank neoplasia. The presence of contrast enhancement in intracranial lesions in patients with NF1 is usually strongly suggestive of tumor. We report the case of a child with NF1 and a focal enhancing brain parenchymal lesion which spontaneously resolved without specific therapy.

Magnetic resonance angiography in children.

MRA in children utilizes the same pulse sequences used in adults, but for investigation of the differing forms of vascular pathology found in the pediatric population. Because of the extreme sensitivity of MRA to motion artifact, sedation is an important adjunct to the performance of diagnostic MRI and MRA in children. Because of the noninvasive nature of MRA, strictly diagnostic conventional angiography in children is uncommonly performed and frequently directed toward investigation and therapy of intracranial vascular malformations. Common indications for MRA in children include sickle cell vasculopathy, cerebral and posterior fossa infarction, tumors, vascular malformations, and follow-up of patients recently on extra corporeal membrane oxygenation (ECMO). Non-invasive follow-up subsequent to surgical or medical therapy of intra or extra cranial vascular pathology is another important use for MRA in children.

In vitro activities of U-100592 and U-100766, novel oxazolidinone antibacterial agents.

Oxazolidinones make up a relatively new class of antimicrobial agents which possess a unique mechanism of bacterial protein synthesis inhibition. U-100592 (S)-N-[[3-[3-fluoro-4-[4-(hydroxyacetyl)-1-piperazinyl]- phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide and U-100766 (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]- 2-oxo-5-oxazolidinyl]methyl]-acetamide are novel oxazolidinone analogs from a directed chemical modification program. MICs were determined for a variety of bacterial clinical isolates; the respective MICs of U-100592 and U-100766 at which 90% of isolates are inhibited were as follows: methicillin-susceptible Staphylococcus aureus, 4 and 4 micrograms/ml; methicillin-resistant S. aureus, 4 and 4 micrograms/ml; methicillin-susceptible Staphylococcus epidermidis, 2 and 2 micrograms/ml; methicillin-resistant S. epidermidis, 1 and 2 micrograms/ml; Enterococcus faecalis, 2 and 4 micrograms/ml; Enterococcus faecium, 2 and 4 micrograms/ml; Streptococcus pyogenes, 1 and 2 micrograms/ml; Streptococcus pneumoniae, 0.50 and 1 microgram/ml; Corynebacterium spp., 0.50 and 0.50 micrograms/ml; Moraxella catarrhalis, 4 and 4 micrograms/ml; Listeria monocytogenes, 8 and 2 micrograms/ml; and Bacteroides fragilis, 16 and 4 micrograms/ml. Most strains of Mycobacterium tuberculosis and the gram-positive anaerobes were inhibited in the range of 0.50 to 2 micrograms/ml. Enterococcal strains resistant to vancomycin (VanA, VanB, and VanC resistance phenotypes), pneumococcal strains resistant to penicillin, and M. tuberculosis strains resistant to common antitubercular agents (isoniazid, streptomycin, rifampin, ethionamide, and ethambutol) were not cross-resistant to the oxazolidinones. The presence of 10, 20, and 40% pooled human serum did not affect the antibacterial activities of the oxazolidinones. Time-kill studies demonstrated a bacteriostatic effect of the analogs against staphylococci and enterococci but a bactericidal effect against streptococci. The spontaneous mutation frequencies of S. aureus ATCC 29213 were <3.8 x 10(-10) and <8 x 10(-11) for U-100592 and U-100766, respectively. Serial transfer of three staphylococcal and two enterococcal strains on drug gradient plates produced no evidence of rapid resistance development. Thus, these new oxazolidinone analogs demonstrated in vitro antibacterial activities against a variety of clinically important human pathogens.

Preliminary observations on the use of midodrine in treating orthostatic hypotension in familial dysautonomia.

Midodrine, a peripheral alpha-adrenergic agonist, was evaluated in 7 female and 2 male patients with familial dysautonomia (FD), a disorder characterized by decreased sympathetic innervation. Prior to and after three months of midodrine treatment, each patient's response to postural change was assessed by arteriosonde readings of blood pressure and heart rate, corrected QT-interval measurements, Doppler evaluation of renal blood flow and circulating atrial natriuretic peptide (ANP) levels. The initial midodrine dose (2.5 mg three times daily) was raised until subjective symptoms improved. Doses were reduced if patients felt jittery or developed erect hypertension (systolic > 180 mmHg or diastolic > 110 mmHg). Midodrine, at an average dose of 0.25 mg/kg per day, improved subjective symptoms in all patients. With treatment, magnitude of blood pressure responses was variable. Although mean erect blood pressure did not increase significantly for the aggregate, it did increase in six of nine patients. In addition, the QTc interval normalized and erect renal perfusion improved. Changes in supine mean blood pressure and supine circulating ANP correlated directly. We judge midodrine to be useful in management of orthostatic hypotension in patients with familial dysautonomia.

Rectal thiopental sodium for sedation of pediatric patients undergoing MR and other imaging studies.

PURPOSE: To determine the efficacy and safety of rectal thiopental sodium as a sedation agent for pediatric imaging. METHODS: Four hundred sixty-two infants and children were sedated with rectal thiopental sodium for MR, CT, or nuclear imaging in 1992 and 1993. Patients received screening histories and physical examinations before sedation, and parents gave informed consent. Sedated patients were monitored by pulse oximetry and direct observation. Twenty-four-hour telephone follow-up to assess delayed side effects was performed successfully in 325 patients. RESULTS: Examinations were successfully completed in 96% of patients. The average time from drug administration to sedation was 12.2 minutes. The average time from sedation to discharge from radiology was 71.1 minutes. Eleven percent of patients had desaturation below the pulse oximetric baseline easily treated with oxygen and head positioning. Twenty-four-hour telephone follow-up in 325 patients revealed a 34% incidence of minor rectal irritation and diarrhea, sleepiness, nausea and vomiting, or ataxia. CONCLUSIONS: Rectal thiopental sodium is a safe and effective drug for pediatric sedation.

Induction of gastroduodenal prolapse by antral heterotopic pancreas.

Ectopic pancreas is the most common congenital anomaly in the gastric antrum. In some patients, there is a distinct tendency for this lesion to produce intermittent crampy abdominal pain by provoking gastroduodenal prolapse. This condition should be considered after a more distal prolapse from intussusception is excluded. An upper gastrointestinal series performed during an episode of symptoms may be diagnostic of this entity.

Understanding the process of quantitative ultrasonic tissue characterization.

Because the human vision system cannot distinguish the broad range of gray values that a computer visual system can, computerized image analysis may be used to obtain quantitative information from ultrasonographic (US) real-time B-mode scans. Most quantitative US involves programming an off-line computer to accept, analyze, and display US image data in a way that enhances the detection of changes in small-scale structures and blood flow that occur with disease. Common image textural features used in quantitative US tissue characterization consist of first-order gray-level statistics (eg, occurrence frequency of gray levels independent of location or spatial relationship) and second-order gray-level statistics dependent on location and spatial relationship, including statistical analysis of gradient distribution, co-occurrence matrix, covariance matrix, run-length histogram, and fractal features. A customized tissue signature software has been developed to analyze image data obtained from clinical US scanners. Means comparison testing and multivariate analysis techniques are used to compare the numbers generated for a particular region of interest. By integrating these techniques into the radiologist's interpretation of the sonogram, the quantitative information gained may lead to earlier detection of lesions difficult to see with the human eye.

Head and neck MR angiography in pediatric patients: a pictorial essay.

Magnetic resonance (MR) angiography is a new, noninvasive imaging method with well-known uses in adults for the evaluation of carotid disease in the neck and cerebral vasculopathy. MR angiography examinations were prospectively studied in 126 children to evaluate the usefulness of MR angiography of the head and neck in children, as well as to correlate its findings with those of conventional angiography. Eleven patients underwent conventional angiography in addition to MR angiography. MR angiography was performed with commercially available pulse sequences and included two- and three-dimensional time-of-flight and phase-contrast techniques. Indications for MR angiography included evaluation of pathologic conditions (aneurysms and arteriovenous malformations, infarcts, venous sinus thrombosis, brain tumors, and cerebritis), screening examinations in sickle cell disease, and follow-up of extracorporeal membrane oxygenation. MR angiography was found to be a useful, noninvasive diagnostic and screening examination for head and neck and cerebral vascular abnormalities in children and had excellent correlation with conventional angiography.