Brain abnormalities in infants on extracorporeal membrane oxygenation: sonographic and CT findings

The findings of cranial sonography performed before and during extracorporeal membrane oxygenation (ECMO) in 50 near-term infants and CT findings after ECMO in 18 of those patients are reported. Hemorrhage is uncommon in patients being considered for ECMO: subependymal hemorrhage was seen in one case and subependymal cyst possibly due to in utero hemorrhage was seen in five cases. Hypoxic ischemic ischemic injury is more common: severe cerebral edema was seen in two cases, occipital hemorrhagic infarct in one case, and mild cerebral edema in 17 cases. During ECMO, sonograms showed that the hemorrhage in patients with small subependymal hemorrhage or cyst before ECMO did not extend while on ECMO. Typical germinal matrix/intraventricular hemorrhage was seen uncommonly (three cases). Unusual parenchymal hemorrhage did occur. Hypoxic ischemic brain injury was more common: parenchymal hemorrhage was seen in three cases, severe cerebral edema in three cases, and infarction in three cases. Hypoxic ischemic brain injury probably occurs before ECMO, with a delay in visualization. CT after ECMO detected additional abnormalities, particularly peripheral areas of hemorrhage and infarction not visible on sonograms, and is now being performed on all patients. More emphasis should be placed on better screening of infants being considered for ECMO treatment to identify irreversible anoxic brain injury, not just hemorrhage.     

Intracranial abnormalities in infants treated with extracorporeal membrane oxygenation: imaging with US and CT

Findings at neuroimaging in 100 consecutive infants treated with extracorporeal membrane oxygenation (ECMO) are presented. Imaging in these infants consisted of pretreatment cranial ultrasonography (US), daily US studies while on ECMO, and follow-up cranial computed tomography (CT) after treatment. There were findings of abnormalities in 43 patients. Thirty had intracranial bleeding, often of unusual extent and distribution. Thirteen additional infants had nonhemorrhagic abnormalities alone. Bleeding considered to be major was seen in 12% of infants. Large parenchymal hemorrhages and infarcts, cerebellar hemorrhages, and diffuse edema were the most significant abnormalities, with a 50% mortality (eight of 16 patients). No lateralization was noted with respect to distribution of bleeding sites or areas of nonhemorrhagic abnormalities. US was a sensitive but imperfect screening tool for intracranial abnormalities. Abnormalities missed with US included peripheral and small parenchymal lesions, subarachnoid hemorrhage, cerebral atrophy, and sagittal sinus thrombosis.     

Posterior fossa intracranial hemorrhage in infants treated with extracorporeal membrane oxygenation: sonographic findings

Posterior fossa hemorrhage was documented by autopsy in five infants who had been treated with extracorporeal membrane oxygenation over a 5-year-period. In all five cases, the diagnosis was made prospectively by cranial sonography. Sonographic findings were compared with those in a control group of 15 infants with normal posterior fossae at autopsy. The following sonographic abnormalities were exhibited in neonates with posterior fossae hemorrhage: loss of definition of the cerebellum and fourth ventricle on midline sagittal images, heterogeneous cerebellar parenchyma, focal hypoechoic lesions, ventricular dilatation, and tentorial abnormalities. Bright foci inferior to the third ventricle were seen in four neonates in the normal control group. These foci measured 5-10 mm in diameter. One cranial sonogram was falsely interpreted as showing a posterior fossa hemorrhage because of prominent echoes in the interpeduncular cistern. Infants treated with extracorporeal membrane oxygenation are at risk for developing posterior fossa hemorrhage. Awareness of sonographic signs and potential pitfalls in the interpretation of posterior fossa hemorrhage is important for early and accurate recognition of these unusual and sometimes treatable hemorrhages.     

Neurologic status in infants treated with extracorporeal membrane oxygenation: correlation of imaging findings with developmental outcome

A retrospective review was done of intracranial images obtained within the newborn period in 46 infants who had been treated with extracorporeal membrane oxygenation (ECMO). A neuroimaging score was determined on the basis of the extent and severity of findings on both ultrasound and computed tomographic scans. Presence of abnormality at neuroimaging and the neuroimaging score were correlated with the findings of neurodevelopmental evaluations (Bayley scales) performed in infants who were at a mean age of 11.8 months (range, 6-16 months). A significant inverse correlation was found between the neuroimaging score and mental and psychomotor development indexes of the Bayley scale (P less than .005). Mean neuroimaging scores in infants with normal development were significantly lower than those in infants with delayed development (P = .002). Although individual outcomes cannot be predicted with neuroimaging, the neuroimaging score can be a useful adjunct in assigning patients who survive with ECMO treatment to risk categories for developmental outcome.     

Chest radiographic findings in neonates on extracorporeal membrane oxygenation

Eight full-term neonates with pulmonary failure were managed with extracorporeal membrane oxygenation (ECMO). Chest radiographs obtained before and during ECMO support were reviewed. During periods of increased flow requirements, the chest radiographs were difficult to evaluate because of increasing pulmonary opacity. During periods of the infants' clinical improvement, their chest radiographs tended to improve as well. A direct cause-and-effect relationship between the pulmonary density and the ECMO flow requirements has not yet been established. The chest radiographs were reliable in confirming correct catheter positions. Routine daily examinations did not demonstrate unsuspected abnormality. Chest radiography during periods of clinical instability, however, added confirmatory evidence to some clinical diagnoses and assisted us in making the diagnosis of an unexpected pneumothorax.     

Thoracic complications of extracorporeal membrane oxygenation: findings on chest radiographs and sonograms.

Neonates treated with extracorporeal membrane oxygenation (ECMO) for respiratory failure have a high frequency of complications related to systemic anticoagulation, ECMO and other life-support lines and catheters, and the antecedent pulmonary disease. Many of these complications involve the thorax and can be defined on chest radiographs or thoracic sonograms. The purpose of this essay is to illustrate the findings of the various thoracic complications of ECMO on chest radiographs and sonograms. This study is based on a review of the medical records and findings on chest radiographs and sonograms of 150 neonates who were treated with ECMO at our institution.     

Cerebrovascular accidents in neonates treated with extracorporeal membrane oxygenation: sonographic-pathologic correlation

Neonates treated with extracorporeal membrane oxygenation are at high risk for the development of intracranial hemorrhage and infarction. The appearance of these lesions on cranial sonography is often unusual and may be confusing. We compared the findings at autopsy with premorbid cranial sonograms in 17 nonsurviving neonates to define better the anatomic basis for the sonographic appearance of these lesions. Macroscopic abnormalities were identified at autopsy in 13 of the 17 neonates. Five neonates had multifocal hemorrhagic white-matter infarcts, three had large parenchymal hemorrhages with adjacent areas of parenchymal necrosis, three had hemorrhagic infarcts of the cerebellum, one had a germinal matrix and intraventricular hemorrhage, and one had bilateral periventricular cysts with surrounding gliosis. All 17 neonates had abnormalities on microscopic examination. Although sonography was accurate in the detection of macroscopic lesions (11 of 13 lesions detected with sonography), the nature and extent of these abnormalities were difficult to judge because of the variable echogenicity of unclotted blood and the presence of focal areas of abnormal echogenicity associated with microscopic calcification and gliosis. Sonography is excellent for the detection of acute cerebrovascular complications during extracorporeal membrane oxygenation, but the appearance of these lesions is variable and nonspecific.     

Cerebral hemodynamics in infants undergoing extracorporeal membrane oxygenation: further observations

Intracranial Doppler ultrasonographic examinations were performed on 64 infants treated with extracorporeal membrane oxygenation (ECMO). Serial studies were performed on the anterior cerebral artery in 55 infants before and during ECMO bypass, and on the middle cerebral arteries (MCAs) and internal carotid arteries (ICAs) on an additional nine infants. The onset of ECMO was associated with changes in character of pulsatile flow, direction of flow, and mean blood-flow velocity. Pulsatility decreased in all patients, and mean blood-flow velocity increased in 73% of patients (mean change from baseline, 87%). Despite retrograde flow in the right ICA in five of nine infants, antegrade flow to the right MCA was preserved in all cases. We found no correlation between alterations in mean blood-flow velocity and overall mortality, frequency of intracranial hemorrhage, and neuro-developmental outcome. These data suggest that wide variations in cerebral blood flow occur with ECMO therapy, and that these changes appear to be well tolerated.     

Cranial sonography of the infant treated with extracorporeal membrane oxygenation

Neonates with severe but reversible pulmonary disease may require therapy beyond conventional ventilatory care. Extracorporeal membrane oxygenation (ECMO) serves as a temporary artificial lung for such infants. Since anticoagulation with systemic heparin is required in the extracorporeal circuit, antecedent hemorrhage may be exacerbated or new hemorrhage precipitated in ECMO patients. While the "usual" periventricular/intraventricular hemorrhage seen in a premature infant may develop, contrasting hemorrhages of unusual extent, uncommon location, or demonstrating unique alterations in internal sonographic character may be precipitated, presumably due to the requisite anticoagulation. Representative examples of such variations are presented along with guidelines for the use of cranial sonography in selecting and monitoring ECMO patients.     

Diffuse pulmonary opacification in infants undergoing extracorporeal membrane oxygenation: clinical and pathologic correlation

Diffuse pulmonary opacification is commonly seen on chest radiographs from infants with severe respiratory failure treated with extracorporeal membrane oxygenation (ECMO). The chest radiographs and clinical records of 18 such infants were reviewed to determine the correlation among degree of abnormality on chest radiograph (as determined by a radiographic score), clinical severity of disease (as measured by ECMO requirements [ECMO flow rate]), and dynamic lung compliance determinations. Increasing lung compliance and decreasing ECMO flow rates correlated well with decreasing (improving) radiographic score. Pathologic changes were mainly those associated with intensive respiratory support and the underlying pulmonary condition. One patient had diffuse pulmonary hemorrhage. Other than bleeding, no distinctive pathologic features could be attributed to therapy with ECMO. We conclude that the degree of pulmonary opacification seen in infants undergoing ECMO therapy is an accurate reflection of markedly decreased lung compliance and lung volumes caused by hyaline membrane formation, pulmonary edema, and atelectasis associated with the various causes of severe respiratory failure.     

Bacterial meningitis in infants: sonographic findings

A retrospective study was performed on 78 patients (newborn to 2 years old) with clinically proved bacterial meningitis. Sonograms were obtained during the acute illness and medical records were reviewed. The spectrum of sonographic features of meningitis included normal scans (30 patients), ventriculomegaly (11 patients), echogenic sulci (31 patients), extra-axial fluid collections (26 patients), abnormal parenchymal echogenicity (9 patients), evidence of ventriculitis (5 patients), and brain abscess (1 patient). In 46 patients, correlation between the sonographic findings and neurologic outcome on clinical follow-up (6 months to 4 years) was made. Findings of abnormal parenchymal echogenicity and/or moderate-to-marked ventriculomegaly were associated with significant neurologic sequelae; however, echogenic sulci and small extra-axial fluid collections did not appear to have any prognostic significance. Twenty-nine of the 78 patients had sonography without clinical indication of complications of meningitis, and in no patient was a significant abnormality found. Our study suggests that sonography is indicated only when there is clinical suspicion of complications.     

Chest and abdominal CT during extracorporeal membrane oxygenation: Clinical benefits in diagnosis and treatment

RATIONALE AND OBJECTIVE: This study aims to evaluate the clinical usefulness of thoracic and abdominal computed tomography (CT) as an adjunct to bedside diagnostic imaging in patients on extracorporeal membrane oxygenation (ECMO) therapy because of severe acute respiratory failure. MATERIALS AND METHODS: Imaging records for 118 consecutive thoracic and abdominal CT examinations performed in 63 patients (22 neonates, 15 children, and 26 adults) on ECMO therapy during an 8-year period were retrospectively reviewed. Reported CT findings were compared with concurrent bedside radiographs and ultrasounds. The clinical importance and effect on treatment of each CT finding was determined by reviewing the medical records. RESULTS: CT showed 30 clinically important complications in 20 different patients that directly impacted on the treatment, but were not diagnosed with bedside imaging. Of the 30 complications, 15 (50%) were surgically treated, 11 (37%) required percutaneous invasive procedures, and 4 (13%) were managed conservatively. Despite the serious complications, 13 of 20 patients (65%) survived. CONCLUSION: Both chest and abdominal CT have an important clinical role in patients on ECMO therapy because of acute respiratory failure, as a complement to bedside imaging, to exclude or show complications and expedite early invasive treatment, when needed.     

Prostatic abscess: CT and sonographic findings

The value of CT and sonography in the diagnosis and follow-up of abscesses of the prostate was studied in six patients with this disease. Five had CT alone, one had CT and sonography, and one had sonography only. CT findings included an enlarged gland with nonenhancing fluid-density collections that sometimes were multiseptated or had enhancing rims. Sonographic findings were similar, showing a hypoechoic mass with thick walls. Follow-up examinations after antibiotic therapy (one CT, one sonogram) showed improvement or resolution. In the patients studied, CT and sonography were useful methods to detect and follow the course of prostatic abscess.     

Hepatic plasmocytoma: sonographic and CT findings

The sonographic and CT features of a case of solitary plasmocytoma of the liver are described. Dynamic CT findings of the tumor differ only slightly from those encountered in cavernous hemangiomas. Liver biopsy under ultrasound or CT guidance followed by immunohistochemical procedure can provide prompt diagnosis of this rare solitary liver tumor.     

CT of cerebrovascular injury after neonatal extracorporeal membrane oxygenation: implications for neurodevelopmental outcome

One hundred forty-six neonates treated with extracorporeal membrane oxygenation (ECMO) were evaluated with cranial sonography and CT at different times in the course of their disease. Cranial sonography was performed during treatment with ECMO, and CT was done 3-14 days after cessation of ECMO bypass. In 66 (45%), intracranial abnormalities were detected with either sonography or CT. Thirty neonates had hemorrhages only, 24 had nonhemorrhagic abnormalities, and 12 had combined lesions. CT provided additional information in 44 (67%) of the 66 neonates. Sonography was normal in 37 neonates, showed fewer lesions in 10 neonates, and was concordant with CT findings in 14 neonates. It cannot be established whether these lesions went undetected with sonography during ECMO, or occurred after cessation of ECMO bypass. Neurodevelopmental evaluation was performed in 71 of 90 survivors 1 year of age or older. Forty-three infants (61%) were normal; developmental delay was suspected in 12 (17%) and present in 16 (23%). The severity of intracranial abnormality as determined by a neuroimaging score correlated well with short-term developmental outcome. Mean neuroimaging scores were significantly higher, with increasing degree of neurodevelopmental delay (p less than .001 by Kruskal-Wallis rank order test). Although cranial sonography remains the primary technique for the detection of life-threatening hemorrhage during ECMO, cranial CT after ECMO is important in defining the total degree of intracranial injury present in these high-risk neonates.