Comparison of transcranial color Doppler imaging (TCDI) and transcranial Doppler (TCD) in children with sickle-cell anemia.

BACKGROUND: Transcranial Doppler (TCD) has been demonstrated to identify those at highest risk of stroke among children with sickle-cell disease. Based on a randomized clinical trial [Stroke Prevention in Sickle-Cell Anemia Trial (STOP)], which ended in 1997, the National Heart Lung and Blood Division of NIH has recommended TCD screening and chronic blood transfusion based on Nicolet TC 2000 dedicated Doppler (TCD). Studies performed using TCD imaging modalities need to be correlated to that used in the clinical trial to provide information for treatment decisions when screening with TCDI. OBJECTIVE: To correlate transcranial arterial time-averaged mean velocities obtained from an Acuson Transcranial Doppler Imaging to those obtained using the TCD as the gold standard for treatment decisions based on STOP. MATERIALS AND METHODS: A total of 29 children with sickle-cell disease, age 3-16 years, were studied at one of two scanning sessions using both techniques and a scanning protocol based on that used in STOP performed and read independently. The average difference in the measured velocities for each arterial segment was tested to determine difference from zero. Differences were compared before and after modifications to the TCDI technique were made to mimic the STOP protocol more closely. RESULTS: TCDI velocities were generally lower than TCD velocities for the same segment, but the difference was reduced (from 15 % to 10% for the middle cerebral artery) by modifications to the TCDI protocol. CONCLUSIONS: Measurements using the Acuson system are modestly lower than those obtained with dedicated Doppler using the Nicolet TCD.

Transcranial Doppler (TCD) screening for stroke prevention in sickle cell anemia: pitfalls in technique variation.

BACKGROUND: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) identified children as being at high stroke risk if the time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries measured > or = 200 cm/s. These values were obtained utilizing a 2-mHz dedicated nonimaging pulsed Doppler technique (TCD) and manual measurements. Questions have been raised as to the comparability of results obtained with different ultrasound machines and measurement techniques. OBJECTIVE: The purpose of this study was to compare nonimaging (TCD) and transcranial duplex imaging (TCDI) findings in children potentially at risk for stroke with sickle cell disease. MATERIALS AND METHODS: Twenty-two children with sickle cell disease and no history of stroke were evaluated by both TCD and TCDI. Examinations were performed on the same day without knowledge of the other modality results and read independently using manually obtained measurements. Mean velocities, peak systolic velocities, and end diastolic velocities obtained by the two techniques were compared. In a subgroup, manual measurements were compared to electronically obtained measurements. RESULTS: TCDI values were lower than TCD measurements for all vessels. TCDI TAMMV values were most similar to the TCD values in the middle cerebral artery (-9.0%) and distal internal cerebral artery (-10.8%), with greater variability in the anterior cerebral artery (-19.3%), bifurcation (-16.3%), and basilar arteries (-23.1%). Risk group placement based on middle cerebral artery TAMMV values did not change when comparing the two techniques. Measurements obtained electronically were lower than those obtained manually. CONCLUSION: Velocities obtained by TCDI may be lower than TCD measurements, and these differences should be taken into consideration when performing screening for stroke risk and selection for prophylactic transfusion based on the STOP protocol.

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.

Dual-energy x-ray absorptiometry in osteopetrosis.

We have used dual-energy x-ray absorptiometry (DXA) in evaluation and follow-up of a patient with osteopetrosis, before and after cord blood transplantation. Other methods of follow-up in such cases have been described, but the use of DXA has not previously been reported. We have shown that DXA offers a safe means of assessing disease progression, the timing of treatment, and response after therapy for osteopetrosis.

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.

Transcranial Doppler imaging in pediatric abnormalities in older children.

Transcranial Doppler (TCD) is a noninvasive diagnostic ultrasound study which uses a 2 megahertz pulsed Doppler transducer to measure the velocity and pulsatility of blood flow within the major intracranial arteries. It has proved to be extremely useful as a screening test or to help confirm the diagnosis of several clinical conditions in infants and children. Some of the proved indications for TCD is for evaluating cerebrovascular occlusive disease especially in screening children with sickle cell disease, hydrocephalus, asphyxia and cerebral edema, confirming brain death, arteriovenous malformations, and vasoplasm. TCD technique, indications, and common pathological findings are emphasized.

Use of power Doppler in pediatric neurosonography: a pictorial essay.

In pediatric neurosonography, conventional color Doppler imaging has been the primary adjunct to routine gray-scale imaging. Power Doppler sonography is a relatively recent development that does not have the limitations of conventional color Doppler ultrasound. The power Doppler technique measures the energy of moving red blood cells instead of the velocity and direction of flow. Advantages of this technique include increased sensitivity for identifying flow in slow-flow states, more complete evaluation of a vessel, and more accurate evaluation of the course of the vessel. Power Doppler sonography is helpful in evaluation of the neonatal brain in a variety of clinical situations: identifying the exact locations of extraaxial fluid collections, differentiating intraventricular clot from normal choroid plexus, detecting intraventricular hemorrhage, and demonstrating asymmetries in cerebral perfusion. However, in certain difficult cases, use of both conventional color Doppler sonography and power Doppler sonography produces increased diagnostic accuracy because these techniques furnish complementary information.

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.

Tibial length following intraosseous infusion: a prospective, radiographic analysis.

Intraosseous infusion is a well accepted means of obtaining emergency intravascular access in children. Despite the low incidence of serious complications from intraosseous infusions, the potential exists for growth plate injury and subsequent growth disturbance following intraosseous infusion. We conducted a prospective, blinded observational study of 10 subjects to evaluate tibial length discrepancy radiographically one year or more following intraosseous infusion. We found no significant difference in mean tibial length between the legs that had intraosseous infusions and the opposite legs, which served as controls. We conclude that intraosseous infusion does not appear to produce subsequent leg length discrepancy one year after infusion.

Neonatal ultrasonography to distinguish between meconium ileus and ileal atresia.

Meconium ileus can be difficult to distinguish from ileal atresia on plain radiographs and on contrast enema. Both show a microcolon in the face of a small bowel obstruction. The treatment of the two is very different. Meconium ileus obstruction may be relieved medically by contrast enema; ileal atresia requires prompt surgical intervention. This study was made to determine if abdominal ultrasonography might be helpful in distinguishing between these two entities. Abdominal ultrasonograms from the past 10 years of all patients with these two diseases who were studied with preoperative ultrasonography at Arkansas Children's Hospital were reviewed. Six of 16 patients with meconium ileus had preoperative ultrasonograms. All six patients with meconium ileus had multiple loops of bowel filled with very echogenic thick meconium. Four of 22 patients with ileal atresia had preoperative ultrasonograms. These four patients with ileal atresia had dilated loops of bowel filled with fluid and air. None had a dilated bowel filled with thick echogenic contents. Preoperative abdominal ultrasonography is proposed as a simple method for distinguishing between these two disease entities with very different treatment plans.

Clinical effect of a quality assurance system for radiographs in a pediatric emergency department.

The objective of this study was to determine the clinical relevance and effectiveness of a quality assurance system used to identify discordant x-ray interpretations between emergency department pediatricians and pediatric radiologists in the emergency department of a large pediatric hospital. Of 5862 patients who underwent 8174 radiographic studies during a one year period, 286 patients with discordant radiographic diagnoses were identified. The incidence of discordant radiograph interpretation was determined to be 3.5% (286/8174 studies). Of those patients with discordant diagnoses, 11.5% (33/286 discordant diagnoses) received immediate intervention by the emergency department, 64.0% (183) received subsequent intervention at their follow-up appointment or by the inpatient team caring for them, 9.4% (27) required no intervention, and 15.0% (43) had no evidence of necessary intervention documented on their medical record. While only 33/5862 (0.6%) patients receiving radiographs after routine working hours required immediate intervention by the emergency department, this intervention was potentially lifesaving. No adverse outcomes were identified in this group of patients who did not receive immediate interpretation of their radiographs by a radiologist. When 24-hour in-house radiology coverage is not provided, a quality assurance system that recalls patients identified with discordant radiographic diagnoses, who may require a change in management, appears to be an effective method of patient management only when discordant interpretations are identified and promptly acted upon.

Cerebral artery Doppler ultrasonography for prediction of outcome after perinatal asphyxia.

Perinatal asphyxia is the most common cause of neurologic injury and neurodevelopmental delay. The signs of injury are nonspecific at birth, and most indicators take hours to days before they become manifest. Early recognition of the injury is important in guiding management during those critical first days of life. Over a five-year period, we investigated 16 term neonates with a history of asphyxia on the first day of life who demonstrated on intracranial Doppler sonography cerebral vessel high diastolic flow with a resistive index below 60. Two infants died and one was lost to follow-up. Three of the remaining 13 patients were normal at 8 months to 1 year follow-up. The remaining 10 patients had severe neurodevelopmental delay with profound handicaps at follow-up periods from 3 months to 32 months. This study has confirmed earlier reports that in the first days of life, a very low resistive index combined with history of asphyxia is associated with an adverse outcome and may be considered one of the earliest markers for poor neurodevelopmental outcome. Only 50% of these patients demonstrated abnormal sonographic imaging.

Cerebrovascular disease in symptomatic and asymptomatic patients with sickle cell anemia: screening with duplex transcranial Doppler US--correlation with MR imaging and MR angiography.

PURPOSE: The authors evaluated the role of transcranial Doppler ultrasonography (US) in patients with sickle cell disease (SCD) and cerebrovascular disease. MATERIALS AND METHODS: Twenty-one patients with SCD and stroke (aged 3-22 years; mean age at stroke, 9 years) were evaluated with magnetic resonance (MR) imaging and duplex transcranial Doppler US with a 2-MHz transducer. Nineteen patients also underwent MR angiography. Forty-six asymptomatic patients with SCD were also evaluated with Doppler US, MR imaging, and MR angiography. RESULTS: The following transcranial Doppler US findings were correlated with cerebrovascular disease in patients with SCD: (a) maximum velocity in the ophthalmic artery (OA) of more than 35 cm/sec; (b) mean velocity in the middle cerebral artery (MCA) of more than 170 cm/sec; (c) resistive index in the OA of less than 50; (d) velocity in the OA greater than that of the ipsilateral MCA; and (e) maximum velocity in the posterior cerebral, vertebral, or basilar arteries greater than the maximum velocity in the MCA. CONCLUSION: Transcranial Doppler US scanning has great potential as an inexpensive, easily performed screening procedure for cerebrovascular disease in patients with SCD.

Use of ultrasound in the detection of occult bowel perforation in neonates.

Intestinal perforation is a common and serious complication of NEC in neonates. Plain film evidence often is absent in patients with surgically proved perforation. Some patients with NEC develop a distended, gasless abdomen suitable for sonographic evaluation. Five neonates with gasless abdominal distention and clinical decline were studied with ultrasonography. Four patients demonstrated intraperitoneal fluid-debris levels and ascites; all had surgical proof of perforation. The fifth patient did not demonstrate these findings and subsequently recovered. The sonographic findings of ascites and intraperitoneal fluid-debris levels in patients with NEC are suggestive of perforation.

Inadvertent transcervical catheterization of the uterus in an infant with intraperitoneal injection of a contrast medium.

A case is presented in which attempted catheterization of the urethral meatus resulted in the inadvertent catheterization of the cervical os. Visualization of the urethral meatus is a requisite for successful catheterization of infant females and young girls.

Evaluation of the reconstructed carotid artery following extracorporeal membrane oxygenation.

Over a 12-month period, 28 neonatal patients in respiratory failure were supported with extracorporeal membrane oxygenation (ECMO), and 11 of these underwent successful repair of the right carotid artery post-ECMO. Nine of 11 were studied with duplex color-flow Doppler imaging between 14 and 109 days of age and again at 1 year of age. A velocity ratio (A/B) of the peak systolic velocity above the level of the anastomosis to the peak systolic velocity below the anastomosis was measured to assess the degree of stenosis, if any, at the repair site. Antegrade flow through the carotid was detected post-ECMO in 8 of 9 infants, and antegrade and retrograde flow was documented in 1 infant. A/B ratios ranged from 1.00 to 8.60 (A/B ratio of 1 is normal; 2.0 indicates at least a 50% obstruction to flow). Four of 9 patients had ratios greater than 2.0, and 8 of 9 exhibited some evidence of obstruction. Follow-up scans were performed on 8 of 9 infants between 12 and 18 months of age. All infants examined showed marked improvement in A/B ratio and patency of the vessel, documenting that initial narrowing of the vessel is reversible. No infant had evidence of embolic phenomena to the right side of the brain by magnetic resonance imaging. Repair of the common carotid artery post-ECMO is technically feasible without increasing the risk of brain injury.

CT and ultrasound imaging of retropharyngeal abscesses in children.

PURPOSE: To show the role of ultrasound (US) in distinguishing retropharyngeal abscess from adenitis in children. METHODS: Eleven infants and children had clinical symptoms suggestive of retropharyngeal infection. Radiographic evaluation included, lateral neck radiography (11/11), contrast-enhanced neck CT (10/11), contrast-enhanced neck MR (1/11), and real time US (11/11) patients. US was used to characterize masses as solid (adenitis) or complex (abscess) and for guiding intraoperative aspiration and drainage. RESULTS: Contrast CT and MR showed findings suspicious for abscess in all 11 cases. Only three children had surgically drainable abscesses. CT numbers within inflammatory masses did not distinguish adenitis from abscess. US was able to correctly diagnose abscess or adenitis in each case. CONCLUSION: Lateral neck radiography and contrast CT identify and localize retropharyngeal inflammatory masses in children. US, but not CT, distinguishes between adenitis and abscess and aids in intraoperative aspiration and drainage.

High resolution ultrasound with Doppler: a diagnostic adjunct in orbital and ocular lesions in children.

Twenty-six infants and children with orbital and ocular pathology were examined with ultrasound (US) utilizing real-time imaging and Duplex Pulsed Doppler evaluation. Twenty-two of these patients underwent concurrent orbital computed tomography (CT) and two had magnetic resonance imaging (MRI). Orbital and periorbital lesions included hemangioma, dermoid, lymphangioma, rhabdomyosarcoma, encephalocoele and abscess. Ocular lesions included infection, trauma, retinal detachment, retinoblastoma, Coat's disease, and persistent hyperplastic primary vitreous. High resolution US with Doppler provided unique diagnostic information in patients with penetrating ocular trauma, orbital and periorbital masses, and intraocular structural abnormalities. High resolution US examination of the eye and periorbital tissues is readily performed using widely available equipment and often delineates subtle structural abnormalities not shown by CT or MRI.

Osteomyelitis in children with sickle cell disease: early diagnosis with contrast-enhanced CT.

Two children with sickle cell disease and osteomyelitis were treated. In one child, definitive treatment was delayed until computed tomography (CT) revealed a subperiosteal abscess. Early performance of CT in the other child resulted in prompt diagnosis and treatment. Before the appearance of the characteristic plain radiographic findings, diagnosis of osteomyelitis in patients with sickle cell disease can be difficult because the clinical manifestations of infarction and osteomyelitis can be similar. Radionuclide scans have yielded mixed results. In equivocal cases, early performance of CT can help establish the diagnosis of osteomyelitis to avoid significant morbidity.

Abscess of the iliopsoas muscle diagnosed by magnetic resonance imaging and ultrasonography.

We have reported a case of abscess of the iliopsoas muscle, in which a limp and hip pain pointed toward pathology of the hip. The diagnosis in such cases may be difficult unless there is close attention to the clinical history and a good physical examination is obtained. One ultrasonographic examination of the hip in such a patient, subtle differences between the iliopsoas muscles should alert the radiologist to examine the psoas muscle. Ultrasonography is instrumental in demonstrating the solid or cystic nature of the iliopsoas mass, while MRI depicts the extent and proximity of adjacent organs. Once an iliopsoas abscess is diagnosed, treatment includes parenteral antibiotics and drainage.