Limitations of T2*-Gradient Recalled-Echo and Susceptibility-Weighted Imaging in Characterizing Chronic Subdural Hemorrhage in Infant Survivors of Abusive Head Trauma.

A possible misconception among radiologists is that chronic subdural hemorrhage should show some degree of blooming on T2*-gradient recalled-echo or susceptibility-weighted sequences such as SWI and susceptibility-weighted angiography, which is not necessarily true. We present 5 cases of chronic subdural hemorrhages in infants, demonstrating intensity near or greater than that of CSF with variable amounts of hemosiderin staining along the neomembranes. We review the physiology and MR imaging physics behind the appearance of a chronic subdural hemorrhage, highlighting that the absence of a BBB can allow hemosiderin to be completely removed from the subdural compartment. Finally, we stress the importance of reviewing all multiplanar sequences for the presence of neomembranes, which can be quite subtle in the absence of hemosiderin staining and are critical for making the diagnosis of chronic subdural hemorrhage.

Parenchymal Brain Laceration as a Predictor of Abusive Head Trauma.

BACKGROUND AND PURPOSE: Accurate differentiation of abusive head trauma and accidental head injury in infants and young children is critical and impacts clinical care, patient prognosis, forensic investigations, and medicolegal proceedings. No specific finding seen on cross-sectional brain imaging has been reported to distinguish abusive head trauma from accidental injury. Our study investigated whether a specific imaging finding, parenchymal brain laceration, is unique to children diagnosed with abusive head trauma. MATERIALS AND METHODS: We retrospectively identified 137 patients with abusive head trauma and 28 patients who incurred moderate to severe accidental brain injury. Brain MR imaging represented the imaging standard for characterizing intracranial injuries. RESULTS: Among the abusive head trauma cohort, parenchymal brain lacerations were identified in 18 patients, while none were identified in any patients with accidental injury. CONCLUSIONS: Our findings are in concurrence with the existing forensic, pathology, and imaging literature, which suggests that parenchymal brain lacerations may be related to abusive injury mechanisms.

Does intracranial venous thrombosis cause subdural hemorrhage in the pediatric population?

Unexplained SDH in infants and children is an accepted marker for AHT. It has been proposed that IVT may be the initiating event leading to the development of acute SDH, mimicking the appearance of traumatic SDH. Our study aims to investigate if nontraumatic IVT causes SDH in the pediatric population. We retrospectively identified 36 patients with IVT and reviewed neuroimaging studies for the concurrent presence of SDH. In our 36 patients with IVT, no associated SDH was observed. Even with extensive IVT, no SDH was present. Three false-positive diagnoses of IVT were identified in the setting of mastoiditis and traumatic SDH, demonstrating pitfalls in imaging. In conclusion, our findings do not support the previous AHT literature stating that IVT is associated with, or leads to, SDH in neonates, infants, or children.

Pilomyxoid astrocytoma: expanding the imaging spectrum.

BACKGROUND AND PURPOSE: Pilomyxoid astrocytoma (PMA) is a recently described variant of pilocytic astrocytoma (PA) with unique clinical and histopathologic characteristics. Because the histopathology of PMA is distinct from that of PA, we hypothesized that PMAs would display distinctive imaging characteristics. We retrospectively reviewed the imaging findings in a large number of patients with PMA to identify these characteristics. MATERIALS AND METHODS: CT and MR images, pathology reports, and clinical information from 21 patients with pathology-confirmed PMA from 7 institutions were retrospectively reviewed. CT and MR imaging findings, including location, size, signal intensity, hemorrhage, and enhancement pattern, were tabulated. RESULTS: Patients ranged in age from 9 months to 46 years at initial diagnosis. Sex ratio was 12:9 (M/F). Twelve of 21 (57%) tumors were located in the hypothalamic/chiasmatic/third ventricular region. Nine (43%) occurred in other locations, including the parietal lobe (2/21), temporal lobe (2/21), cerebellum (2/21), basal ganglia (2/21), and fourth ventricle (1/21). Ten (48%) tumors showed heterogeneous rim enhancement, 9 (43%) showed uniform enhancement, and 2 (9%) showed no enhancement. Five (24%) masses demonstrated intratumoral hemorrhage. CONCLUSION: This series expands the clinical and imaging spectrum of PMA and identifies characteristics that should suggest consideration of this uncommon diagnosis. One third of patients were older children and adults. Almost half of all tumors were located outside the typical hypothalamic/chiasmatic region. Intratumoral hemorrhage occurred in one quarter of patients. PMA remains a histologic diagnosis without definitive imaging findings that distinguish it from PA.

Absent semicircular canals in CHARGE syndrome: radiologic spectrum of findings.

BACKGROUND AND PURPOSE: This paper describes the CT findings that characterize the middle and inner ear anomalies in coloboma, heart defects, choanal atresia, mental retardation, genitourinary, and ear anomalies (CHARGE) syndrome. With this information, neuroradiologists will be better prepared to provide clinically relevant information to their referring physicians regarding this rare syndrome. MATERIALS AND METHODS: CT studies from 13 patients were reviewed by 2 neuroradiologists with Certificate of Additional Qualification. Each ear was counted separately for a total of 26 ears. Middle and inner ear anomalies associated with CHARGE syndrome were categorized. Investigational review board approval was obtained. RESULTS: Twenty of 26 (77%) ears demonstrated cochlear aperture atresia. Four of these ears were evaluated with MR imaging and were found to lack a cochlear nerve. Twenty-one of 26 (81%) cochlea had some form of dysplasia. Six of 26 (23%) round windows were aplastic. Three of 26 (12%) round windows were hypoplastic. Twenty-one of 26 (81%) oval windows were atretic or aplastic. Fifteen of 26 (58%) vestibules were hypoplastic or dysplastic. There were 5 of 26 (19%) enlarged vestibular aqueducts. Twelve of 26 (46%) vestibular aqueducts had an anomalous course. All cases demonstrated absent semicircular canals. Twenty-three of 26 (88%) facial nerve canals had an anomalous course. Four of 26 (15%) tympanic segments were prolapsed. Three of 26 (12%) temporal bones had an anomalous emissary vein referred to as a petrosquamosal sinus. Twenty-one of 26 (81%) middle ear cavities were small. Twenty-three of 26 (93%) ossicles were dysplastic with ankylosis. Three of 26 (12%) internal auditory canals were small. CONCLUSION: The CT findings that correlate to the anomalies of CHARGE syndrome affect conductive as well as sensorineural hearing. Stenosis of the aperture for the cochlear nerve aperture on CT is suggestive of hypoplasia or absence of the cochlear nerve, which has been demonstrated in some cases by MR. Absence of the cochlear nerve would be a contraindication to cochlear implantation.

CT, MRI and MRS of Epstein-Barr virus infection: case report.

We report MRI and proton MR spectroscopy (MRS) findings in a 12-month-old girl with Epstein-Barr virus encephalitis. CT and MRI showed focal lesions in the basal ganglia. MRS of the lesions showed decreased N-acetyl aspartate and elevation of some amino acids, indicating an infectious rather than ischemic etiology. This case illustrates the use of MRS to narrow differential diagnosis.

Enlarged parietal foramina: association with cerebral venous and cortical anomalies.

OBJECTIVE: To evaluate a series of patients with enlarged parietal foramina for associated brain anomalies. BACKGROUND: Enlarged parietal foramina are usually considered a benign calvarial defect. METHODS: Ten patients with enlarged parietal foramina were identified. Seven patients were evaluated with neuroimaging: two by cranial CT and five by CT and/or MRI. Three patients who underwent MRI also underwent MR angiography or MR venography. RESULTS: Six of seven patients had cranial imaging showing a persistent falcine venous sinus. Three of six patients had variations of occipital cortical infolding. One patient had focal encephalomalacia in close proximity to the persistent falcine venous sinus and one had a previously undiagnosed atretic occipital encephalocele. CONCLUSION: This constellation of findings suggests that aberrant vascular evolution during fetal development may affect cerebrovascular, brain, or skull development. Individuals with enlarged parietal foramina (>5 mm) warrant imaging of underlying brain parenchyma and vasculature.

Single central maxillary incisor with nasal pyriform aperture stenosis--CT diagnosis prior to tooth eruption.

Two children with nasal pyriform aperture stenosis had the diagnosis of single central maxillary incisor made with CT scanning prior to tooth eruption and the clinical appreciation of this finding. The surgical and clinical implications of this diagnosis will be presented.

MRI diagnosis of suspected atlanto-occipital dissociation in childhood.

OBJECTIVE: To demonstrate the utility of magnetic resonance (MR) imaging in the diagnosis of complete and partial ligamentous injuries in patients with suspected atlanto-occipital dissociation (AOD). MATERIALS AND METHODS: Five patients with suspected AOD had MR imaging performed within an average of 4 days after injury. MR scans were reviewed with specific analysis of craniocervical ligamentous structures. Charts were reviewed to obtain clinical information regarding presentation, treatment, hospital course, and outcome. RESULTS: Two patients demonstrated MR evidence of complete AOD. One had disruption of all visualized major ligamentous structures at the craniocervical junction with anterolisthesis and evidence of cord damage. The second had injuries to the tectorial membrane, superior band of the cruciform ligament, apical ligament, and interspinous ligament at C 1-2. The remaining three patients sustained incomplete severance of the ligamentous structures at the craniocervical junction. All patients demonstrated subtle radiographic findings suggestive of AOD, including soft tissue swelling at the craniocervical junction without fracture. The two patients with complete AOD died. The three patients with partial AOD were treated with stabilization. On follow-up, these three children were asymptomatic following their craniocervical injury. CONCLUSION: MR imaging of acute AOD provides accurate identification of the craniocervical ligaments injured, classification of full versus partial ligamentous disruption, and analysis of accompanying spinal cord injury. This information is important for early appropriate neurosurgical management and preservation of neurologic function in survivors.

Aggressive manifestations of inflammatory pulmonary pseudotumor in children.

We present three cases that illustrate the locally invasive radiographic appearance that inflammatory pulmonary pseudotumor can assume. Awareness and inclusion of inflammatory pseudotumor in the differential diagnosis of aggressive pleuropulmonary and mediastinal processes may have critical treatment implications.

Neuroimaging of postnatal pediatric central nervous system infections.

Pediatric neuroimaging plays an important role in the timely diagnosis of postnatal central nervous system (CNS) infections, and in some patients the imaging findings are sufficiently specific to suggest a cause. The sequela of CNS infection, including hydrocephalus, subdural collections, ischemia/infarction, cerebral abscess, demyelination, and vascular thrombosis, can be accurately depicted and serially followed with current imaging techniques. The purpose of this review is to describe the spectrum of pediatric postnatal CNS infections, emphasizing key pathological and neuroimaging features, and to outline the strengths, weaknesses, and applications of current neuroimaging technology. The prenatal and perinatal infections falling under the designation of TORCH (toxoplasmosis, other [e.g., syphilis, HIV], rubella, cytomegalovirus, and herpes simplex II) are not covered.

The resolution of syringohydromyelia without hindbrain herniation after posterior fossa decompression.

OBJECT: To provide more information about this rare condition, the authors describe five cases of syringohydromyelia without hindbrain herniation. Preoperative magnetic resonance imaging with and without gadolinium-diethylenetriamine pentaacetic acid revealed no evidence of spinal cord tumor, arachnoiditis, or spinal dysraphism. METHODS: Craniocervical decompression was performed in all patients, after which there was resolution of the symptoms in the four symptomatic patients, and all five showed marked reduction in the size of the syrinx. CONCLUSIONS: The authors hypothesize the rare occurrence of syringohydromyelia resulting from a Chiari-like pathophysiological condition but lacking a hindbrain hernia. Patients with this condition may benefit from craniocervical decompression.

Peritoneal metastases in children with cancer.

BACKGROUND: This study attempted to evaluate the childhood malignancies associated with computed tomography (CT) detected peritoneal metastases as well as the diagnostic imaging characteristics of these metastases as shown on CT. METHODS: The authors reviewed all available pathology specimens and abdominopelvic CT scans of patients identified as having peritoneal metastases at three childhood cancer centers. Patient demographics, primary diagnosis, and CT characteristics of such metastases were evaluated. RESULTS: Peritoneal metastases were identified by CT in 32 children with cancer either at diagnosis (n = 20) or up to 6.2 years from diagnosis (n = 12). On CT, peritoneal disease appeared as a mass in 26 cases, as studding in 11 cases, as peritoneal enhancement in 15 cases, and as diffuse caking in 4 cases (15 patients had > 1 category of peritoneal metastasis). Thirteen patients had concurrent metastases in other sites. Fourteen patients died of progressive disease at a median of 10 months from the time peritoneal metastases were identified on CT. At last follow-up, the remaining 18 patients were alive, with follow-up ranging from 1 month to 9.7 years. As expected, peritoneal metastases were identified in patients with germ cell tumors and colon carcinoma. However, they also were observed in patients with epithelioid carcinoma, leiomyosarcoma, pineoblastoma, neuroblastoma, melanoma, and peripheral neuroectodermal tumor. CONCLUSIONS: Peritoneal metastases have variable appearance on CT, but most commonly appear mass-like. They are associated with a wider range of primary diagnoses than reported previously. The outcome varies with the type of the primary tumor and its responsiveness to existing therapies.

Prostaglandin E1-induced hyperostosis: clinicopathologic correlations and possible pathogenetic mechanisms.

Prostaglandin E1 (PGE1) causes skeletal hypertrophy, a phenomenon noted when it is administered for several weeks to maintain ductus arteriosus patency in neonates with congenital heart disease. This effect, a dose-dependent and reversible hyperostosis, was described radiologically as bone within bone, but skeletal histopathology was not studied. We compared postmortem gross, radiological, and histological bone findings for untreated controls and term gestation infants after 4, 27, and 56 days of continuous 0.1-0.2 microgram/kg/min PGE1. Bone was not significantly different from controls after 4 days of PGE1. Radiographs were negative after 27 days, but femoral cortex showed early periosteal osteoblast proliferation. At 56 days of PGE1, there was severe, radiologically apparent neocortex formation in tubular, rib, and scapular bones. Corresponding sections of femoral shaft revealed distinctive histopathology with thickened periosteum and fibrocartilage-like tissue covering an exuberant neocortex of closely aligned, gracile, woven bone trabeculae. Paratrabecular stroma contained ectatic capillaries orthogonally oriented to the periosteum, suggesting that a vascular reaction to PGE1 is important in the observed effect. The native cortex was partially resorbed; because it is stress shielded by the neocortex and no inflammation was present, this was interpreted as a secondary effect. We conclude that PGE1-associated paracortical bone hypertrophy is distinct from inflammatory processes and that its early stages may not be apparent radiologically. Moreover, the time course of PGE1-induced osteoblast proliferation and mineralization suggests that experimental use for 4-8 weeks may benefit conditions such as ununited fractures.

Diabetes insipidus and histiocytosis X: a case of isolated pituitary involvement.

Diabetes insipidus is associated with histiocytosis X in approximately 50% of cases with multiple lesions that involve both intracranial and extracranial structures. Although approximately 8% of cases of diabetes insipidus in children are caused by involvement of the hypothalamus or pituitary infundibulum (or both) by histiocytosis X, diabetes insipidus can be the initial manifestation in many disorders most commonly, intracranial neoplasms. Herein we report a case of isolated histiocytosis X of the pituitary gland in a child for whom medical assistance was sought because of symptoms of diabetes insipidus.