Initial clinical experience with high-pitch dual-source CT as a rapid technique for thoraco-abdominal evaluation in awake infants and young children.

AIM: To evaluate dual-source high-pitch computed tomography (HPCT) imaging of the chest and abdomen as a rapid scanning technique to obtain diagnostic-quality imaging evaluation of infants and young children without sedation. MATERIALS AND METHODS: Fifty-three paediatric patients (age 24.1±2 months) who underwent chest or abdomen HPCT (≥1.5) and standard pitch CT (SPCT, <1.5) on a dual-source 128-row multidetector CT system were included in the study. Image quality assessment was performed by two paediatric radiologists for diagnostic confidence, image artefacts, and image noise. Objective image noise was measured. RESULTS: Most of the CT examinations were performed in children who were >1 year old (n=15 and n=20) followed by ≤1 year old (n=8 and n=10) in SPCT and HPCT, respectively. The mean radiation dose (SSDE) from HPCT was 1.96±1 mGy compared to 2.2±1 mGy for SPCT (p=0.3). No major artefacts were reported and overall image quality of all HPCT examinations was acceptable diagnostically. In addition, objective image noise values were not significantly different between HPCT compared with SPCT (11±3 versus 11±5, p=0.7). CONCLUSION: Ultra-fast, HPCT can be performed without the need for sedation as a potential alternative to anaesthetised magnetic resonance imaging in infants and young children.

Perioperative transcranial Doppler US to evaluate intracranial compliance in young children undergoing craniosynostosis repair surgery.

PURPOSE: To determine whether measurements with transcranial Doppler ultrasonography (US) of resistive indexes (RIs) of basal cerebral arteries with pressure provocation can be used to identify infants and children with craniosynostosis who have abnormal intracranial compliance and to study the effects of surgery on compliance. MATERIALS AND METHODS: Transcranial Doppler US was performed through the temporal squama, fontanels, and existing skull defects prior to and immediately following cranioplasty. Twenty-four studies were performed in six patients with multisuture synostosis, and 61 studies were performed in 26 patients with single-suture synostosis. Study findings were compared with those of 23 control subjects and were characterized as normal or abnormal on the basis of age-specific normal criteria for RI. RESULTS: In multisuture synostosis, results of six of the nine preoperative transcranial Doppler US studies were abnormal. During postoperative follow-up, three recurrences requiring reoperation occurred, one of which was detected with abnormal transcranial Doppler US findings. In single-suture synostosis, results of seven of the 26 preoperative transcranial Doppler US studies were abnormal, and all occurred in young infants with sagittal and unicoronal synostosis. Immediate effects of surgery were variable. All patients with sagittal synostosis had a significant immediate postoperative increase in RI, which normalized during postoperative follow-up. There was no significant difference in RI between patients with successfully treated craniosynostosis and control subjects. CONCLUSION: Transcranial Doppler US can be used to identify patients with craniosynostosis with decreased intracranial compliance, and it is a suitable noninvasive test to monitor the effects of surgery on compliance.

Pulmonary emboli following therapeutic embolization of cerebral arteriovenous malformations in children.

BACKGROUND: Reports of the complicating side effect of pulmonary embolism (PE) following endovascular therapy of cerebral arteriovenous malformations (AVM) in children have been limited in number. Details of its occurrence are yet to be fully elucidated. OBJECTIVE: The hypothesis is that inadvertent pulmonary migration of embolic material is common and may go unrecognized. MATERIALS AND METHODS: Forty-seven patients (ages 1 day to 16 years and 11 months) underwent embolization of a cerebral AVM with at least one material (cyanoacrylate, platinum coils, detachable balloons, polyvinyl alcohol particles). The medical records and chest radiographs were reviewed retrospectively. Chest radiographs were available in 34 patients. The radiographs were analyzed for the presence or absence of foreign material in the lungs. RESULTS: The chest radiographs in 12 patients (35%) showed pulmonary deposits of embolic material; cyanoacrylate in 10 patients and platinum coils in 2. Two of the patients with cyanoacrylate deposits in the lungs developed respiratory distress that required endotracheal intubation. The patients gradually improved after a time period of 7-10 days with conservative treatment. CONCLUSION: PE is not an uncommon complication in children undergoing embolization of brain AVM. Although usually asymptomatic, PE may cause severe symptoms.

Cardiac electron-beam CT in children undergoing surgical repair for pulmonary atresia.

PURPOSE: To study whether electron-beam computed tomography (CT) is as accurate as conventional angiocardiography for the characterization of the true pulmonary arteries and the aortopulmonary collateral vessels in children undergoing surgical correction for pulmonary atresia. MATERIALS AND METHODS: Twenty-three children with pulmonary atresia underwent 48 cardiac-triggered dynamic contrast material-enhanced electron-beam CT studies. Correlation was made with surgical findings in all patients and with 34 cineangiocardiograms. Data from reconstructed electron-beam CT images and cineangiocardiograms were reviewed for the presence, caliber, and origin of true pulmonary arteries and aortopulmonary collateral vessels; for stenosis; for thrombosis; and for the patency of vascular conduits and shunts. RESULTS: Electron-beam CT was more sensitive than angiography in the identification of hypoplastic and/or nonconfluent branch pulmonary arteries, coronary anomalies, conduit and shunt thrombosis, and other postoperative complications, but it was less sensitive in the demonstration of stenoses at collateral vascular origins and anastomoses. Overall test parameters for electron-beam CT and angiography to characterize pulmonary vascularity were similar (sensitivity, 0.94 vs 0.90; specificity, 0.99 for both; accuracy, 0.97 vs 0.95). Three-dimensional reconstructions, although they were helpful in conveying electron-beam CT findings to referring cardiologists and surgeons, did not add diagnostic information to that displayed on images of the transverse sections. CONCLUSION: Electron-beam CT complements conventional diagnostic angiocardiography in preoperative evaluation, especially in the detection of hypoplastic pulmonary arteries. It is well suited for postoperative shunt surveillance.

Three-dimensional helical CT of pulmonary arteries in infants and children with congenital heart disease.

OBJECTIVE: The purpose of our study was to determine the value of three-dimensional reconstructed helical CT in the assessment of the pulmonary arteries in infants and children with complex congenital heart disease. MATERIALS AND METHODS: Twenty patients were examined with contrast-enhanced helical CT. Three-dimensional reconstructions were performed with multiplanar reformations, maximum intensity projection, and shaded-surface display. Correlation was made with 19 echocardiograms and 14 cineangiocardiograms. All imaging studies were reviewed independently for the following parameters: the caliber of the main and branch pulmonary arteries and their confluence, the presence of stenosis, the number and caliber of aortopulmonary collaterals, and the patency of vascular shunts and conduits. Surgical confirmation, which was used as the reference standard, was available in all patients. RESULTS: Helical CT was as accurate as angiocardiography in revealing stenotic and nonconfluent central pulmonary arteries and in revealing aortopulmonary collaterals (overall CT test parameters: sensitivity, 90%; specificity, 100%; accuracy, 93%).Three-dimensional rendition did not improve the accuracy of CT. The patency of shunts was shown equally well with CT as with angiography, but CT showed thrombosis more directly. Echocardiography was the least accurate technique in revealing pulmonary artery anatomy (accuracy, 65%), primarily because a relatively large number of studies were technically unsatisfactory to assess the study parameters. CONCLUSION: Helical CT angiocardiography with three-dimensional reconstruction is superior to echocardiography for the noninvasive assessment of pulmonary artery anatomy in patients with complex congenital heart disease. Helical CT may be used as a complementary technique and occasionally as a substitute for the diagnostic imaging portion of cardiac catheterization with cineangiocardiography.

Transcranial Doppler ultrasonography to evaluate need for cerebrospinal fluid drainage in hydrocephalic children.

The aim of this study was to determine whether the resistive index in the anterior cerebral artery, as measured by transcranial Doppler ultrasonography without and with pressure provocation, predicts the need for cerebrospinal fluid drainage in hydrocephalic children. Both without and with pressure provocation, the resistive index was significantly higher (P > 0.05) in patients with raised intracranial pressure compared with control group patients and dropped significantly after drainage. With receiver operating characteristic analysis, the optimal cutoff point between normal and abnormal resistive index values was determined at 0.71 without pressure provocation and at 0.90 with pressure provocation. The addition of the pressure provocation test improved accuracy from 81 to 91%, mainly by improving specificity. In conclusion, transcranial Doppler ultrasonography with pressure provocation accurately identifies hydrocephalic children who require cerebrospinal fluid drainage procedures.

Noonan syndrome associated with neuroblastoma: a case report.

We report a case of a child with Noonan phenotype and incidental radiographic findings of mediastinal neuroblastoma. Recent studies have reported an increased association of Noonan syndrome with some malignancies, and the case we present here is the first reported case to our knowledge of an association of neuroblastoma with Noonan syndrome.

Carotid artery volume flow: in vivo measurement with time-domain-processing US.

PURPOSE: To evaluate carotid artery volume-flow measurements with time-domain-processing ultrasonography (US). MATERIALS AND METHODS: Volume-flow measurements were obtained in the carotid arteries of nine swine with time-domain-processing US. Four swine were prepared with a model of an arteriovenous shunt. Flow through the carotid artery was varied by means of a number of physiologic and pharmacologic interventions. The reference standard for volume flow consisted of measurements with transit-time US flowmetry. At a limited number of measurement points, this reference standard was validated against true volume flow measured with timed collection. RESULTS: For flow rates less than 500 mL/min, a linear correlation existed between measurements with time-domain processing and the US flow meter (r2 = .96, P < .001, slope = 1.117). Values above 500 mL/min were less well correlated with the reference standard. True flow was underestimated with both methods, less so with time-domain processing than with US flowmetry (underestimation, 10% versus 21%). Measurements were significantly less reproducible with time-domain processing than with US flowmetry (P < .001). Interobserver variability was negligible. CONCLUSION: Because of operator errors, measurements with time-domain processing should be repeated at least three times to ensure accuracy and may be inaccurate in flow rates over 500 mL/min.

Validation of volume flow measurements in blood vessels with quantitative color velocity imaging using a physiologic model of the circulation.

RATIONALE AND OBJECTIVES: Color velocity imaging-quantitative (CVI-Q) is a new sonographic technique designed to measure volume flow (VF) in blood vessels. We attempted to validate VF measurements with CVI-Q in an in vitro model of the circulation. METHODS: We validated CVI-Q in a flow phantom mimicking physiologic conditions by connecting isolated porcine arteries 4-14 mm in diameter to a calibrated perfusion roller pump generating pulsatile flow with porcine blood. Pump flow was varied stepwise from 0 to 1,000 ml/min. CVI-Q VF measurements were performed using a 7.5-MHz linear array transducer. VF results then were compared with pump flow calibration values through linear regression. RESULTS: A good correlation (r2 = .98-.99, slope = 0.88-1.02) was obtained from 0 to 400-600 ml/min. The degree of correlation depended on vessel diameter, with linearity being maintained over a somewhat larger range in medium-sized vessels. At higher flows, variability increased significantly. CONCLUSION: VF measurements with CVI-Q are accurate in a physiologic flow range. At supraphysiologic flow rates, as are encountered within arteriovenous fistulae, CVI-Q may give inaccurate results. Awareness of possible pitfalls and limitations of the technique is important for obtaining accurate and reproducible results.

Decreased cortical and increased cancellous bone in two children with primary hyperparathyroidism.

The basis for this study is two children with primary hyperparathyroidism (PHPT) who radiographically manifested both marked subperiosteal resorption and prominent osteosclerosis. We hypothesize that the parathyroid hormone (PTH) elevation not only increased osteoclastic resorption of cortical bone but also simultaneously enhanced cancellous bone formation, giving rise to osteosclerosis. In this report, we describe the changes in trabecular and cortical bone density, as measured by quantitative computed tomography (QCT), in these two young patients with severe PHPT, before and after removal of a parathyroid adenoma. Before surgery, the radiographic findings of subperiosteal resorption and osteosclerosis were associated with low cortical and high cancellous bone density values in both children. Within 1 week of surgery, both cortical and cancellous bone density values increased and serum concentrations of calcium and, to a lesser degree, phosphorus decreased due to the "hungry bone syndrome." Twelve weeks after parathyroidectomy, QCT bone density values and skeletal radiographs were normal in both patients. The findings suggest that in patients with severe PHPT, the catabolic effect of PTH on cortical bone may be associated with a simultaneous anabolic effect on cancellous bone, and PTH may cause a significant redistribution of bone mineral from cortical to cancellous bone.

Normal US appearance of ovaries and uterus in four patients with Turner's syndrome and 45,X karyotype.

Pelvic ultrasonographic (US) studies of four patients (ages 11-19 years) with Turner s syndrome, 45,X karyotype, and normal ovarian function were reviewed. All four had persistent menses, spontaneous breast development, and normal follicular stimulant hormone (FSH) serum concentrations. The US studies depicted normal postpubertal uterus and normal-sized ovaries with follicles. In three patients, ovaries were seen bilaterally, while in one only one gonad was identified. Radiologists should be aware that patients with Turner s syndrome, even with a single X chromosome, may occasionally have normal genital development.

The value of portal vein pulsatility on duplex sonograms as a sign of portal hypertension in children with liver disease.

OBJECTIVE: The purpose of this study was to determine the significance of portal vein pulsatility on duplex Doppler waveforms in children with end-stage hepatic failure undergoing liver transplantation. SUBJECTS AND METHODS: Thirty-eight children with end-stage hepatic decompensation were examined with color-assisted spectral Doppler waveform analysis of the hepatic artery and the portal vein. Correlation was made with age, duration of illness, clinical and pathologic diagnosis, and presence of portal hypertension. Findings were compared with those for six patients with acute viral hepatitis and 12 healthy control subjects. RESULTS: Portal vein pulsatility was noted in all 36 patients in whom portal vein flow was detected by Doppler imaging. The majority of these (34) had clinical or sonographic evidence of portal hypertension. In two patients, no portal vein flow was identified in the liver hilum; both had a large portosystemic shunt through collaterals or surgical graft. Significantly increased pulsatility of the hepatic artery waveform (resistive index [RI] = 0.89 +/- 0.15, p < .0001) was seen in patients with end-stage liver disease. In contrast, no portal vein pulsatility and normal hepatic artery pulsatility (RI = 0.60 +/- 0.11) was noted in all patients with acute hepatitis and control subjects. CONCLUSION: Portal vein waveform pulsatility is 94% sensitive and 90% specific for portal hypertension in end-stage liver disease.

Imaging of the adrenal gland in children.

Ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging have replaced intravenous urography and angiography in evaluation of children with suspected disease of the adrenal glands. Although the spatial resolution of MR imaging is still somewhat inferior to that of CT, it allows tissue characterization and better evaluation of tumor extension owing to its multiplanar imaging capability. Initial diagnosis of an adrenal mass in a child is made with US, which is also used to document regression of uncomplicated neonatal adrenal hemorrhage. MR imaging is used for evaluation of tumor extension when surgery is to be performed. Imaging findings such as size, shape, and signal intensity are often not specific for a pathologic condition and must be interpreted in conjunction with the patient's age, the clinical history (eg, trauma), results of physical examination (eg, palpable mass or presence of an endocrine syndrome), and hormone levels in blood and urine.

Symptomatic gastroesophageal reflux: diagnosis with ultrasound.

Ultrasound is a new test proven to be sensitive in the demonstration of gastroesophageal reflux (GER). Following reflux seen with ultrasound various symptoms can be observed in physiological circumstances, and thereby a causal relationship between reflux and these symptoms can be observed in physiological circumstances, and thereby a causal relationship between reflux and these symptoms can be proven. We performed a study in 220 children suspected of GER to determine the incidence of sonographically demonstrated "symptomatic reflux" in different clinical groups: children with (1) vomiting only, (2) respiratory symptoms, (3) attack-like symptoms, and (4) pain and irritability. Overall, GER was demonstrated in 78% of all 209 children in whom technically satisfactory studies could be performed. This reflux was associated with symptoms in 32% of the cases. Symptomatic reflux was most frequent in group 3, which included children investigated for near-miss sudden infant death syndrome. The symptoms that were noted most frequently were vomiting, motor unrest, coughing, and wheezing. Apnea, bradycardia and attacks of unusual posturing could incidentally be related to reflux. Ultrasound is a cheap, simple, noninvasive, and physiological test to show clinically significant reflux.

Imaging in pediatric liver transplantation.

Liver transplantation is an accepted and successful mode of treatment for pediatric end-stage liver disease. On the basis of a review of 229 liver transplantations in 185 children, the authors describe the imaging findings of the preoperative evaluation, the uncomplicated transplantation, various postoperative complications, and the suggested percutaneous treatment of some of these complications. The most frequent indications for liver transplantation encountered in this review were biliary atresia (52%), acute fulminant hepatic failure (11%), alpha 1-antitrypsin deficiency (9%), cryptogenic cirrhosis (6%), and chronic active hepatitis (4%). (The remaining 18% were various rare indications, representing < 4% each.) Routine Doppler ultrasound is the modality of choice for the screening of postoperative complications, supplemented with computed tomography, hepatobiliary scintigraphy, and cholangiography or angiography as needed. Familiarity with the normal graft appearance, as influenced by various surgical and technical factors, and knowledge of the underlying condition of the patient and the clinical course of postoperative complications are crucial for a correct interpretation of the findings from imaging studies.

Pediatric intracranial vascular malformations: evaluation of treatment results with color Doppler US. Work in progress.

To determine the value of color Doppler ultrasound (US) in the preoperative assessment and evaluation of treatment results in children with intracranial vascular malformations (VMs), the authors performed 36 color Doppler US studies in nine children who underwent endovascular embolization. Color flow imaging with spectral waveform analysis of feeding arteries, nidus, draining veins, and uninvolved cranial vasculature was performed, and correlation was made with other imaging findings. In most VMs, color Doppler US enabled the authors to map the lesion completely. Hemodynamic changes after embolization included improvement in blood supply to uninvolved portions of the brain and increase in caliber and flow of feeding vessels that were not occluded during embolization. Serial volume flow measurements were performed with Doppler US in major extracranial arteries. Success of embolization was indicated by substantial decrease of total carotid artery flow. Color Doppler US is a noninvasive modality that adds important imaging and hemodynamic data to those provided by angiography.

Congenital bladder rupture and urine ascites secondary to a sacrococcygeal teratoma.

A case of congenital bladder rupture with urine ascites and bilateral hydronephrosis secondary to a sacrococcygeal teratoma obstructing the bladder outlet is presented. As no evidence of pulmonary hypoplasia and renal dysplasia was present, with rapid recovery of renal function after decompressive surgery, the infravesical obstruction probably occurred late in the fetal period. The bladder rupture resulting in internal decompression may have constituted an additional protective mechanism for the preservation of renal function.

The pediatric patient with suspected adrenal neoplasm: which radiological test to use?

To establish which radiological test to use in a pediatric patient with suspected neoplasm, we retrospectively studied 19 children with proven adrenal neoplasm who had a combination of ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). The results show that US should remain the initial imaging modality for evaluating abdominal masses in children but that MRI is more accurate than CT and US in detecting the organ of origin and the extent of an adrenal lesion and should, therefore, be the modality of choice for the definitive evaluation of adrenal neoplasm in children.