Bone healing using a bi-phasic ceramic bone substitute demonstrated in human vertebroplasty and with histology in a rabbit cancellous bone defect model.

A non-exothermic material that demonstrates clinical pain relief comparable to polymethylacrylate (PMMA) for vertebroplasty and promotes bone healing is desirable. The purpose of this investigation is to demonstrate clinical pain score improvement and bone healing following vertebroplasty with a novel bi-phasic ceramic cement. Twenty patients were prospectively treated for compression fractures in a single center in the USA with the injectable bi-phasic ceramic bone substitute. Statistical comparison of pain scores was made during a 12 month follow-up retrospectively against a matched cohort of patients treated with PMMA vertebroplasty by the same neuroradiologist (HPH) in the same setting. The bone remodeling material was also evaluated with histology in a New Zealand white rabbit model. The bi-phasic material demonstrated a pre-operative mean VAS score of 8.5 (± 1.6) with a significant post-operative pain relief mean VAS score of 1.8 (± 2.5) after one week, which was maintained throughout the 12 month follow-up period. These data are in line with the pain scores for the PMMA treated cohort. CT scans six and 12 months after surgery with the bi-phasic cement showed healing of the osteoporotic fractures. In the rabbit model, histology with the study material showed evidence of incorporation, new bone growth and bone healing in a cancellous bone defect. Both the clinical results and the histologic evidence of bone healing and new bone growth support the application of this new bioinjectable material as an alternative to the use of PMMA for vertebroplasty.

Neuroimaging in infantile autism.

Metabolic findings using [18F]fluorodeoxyglucose (FDG) with positron emission tomography (PET) and correlative anatomic findings with computed tomography (CT) or magnetic resonance imaging (MRI) were characterized in 13 children with infantile autism. Four of 13 patients had both an abnormal FDG-PET and an abnormal MRI, whereas seven of 13 patients had both a normal FDG-PET and a normal CT or MRI. Sixteen of a total of 195 brain areas qualitatively examined with FDG-PET had a hypometabolic abnormality on PET. Three of the five abnormal structural imaging studies revealed neuronal migrational anomalies (focal pachygyria). In two of the five patients with anatomic abnormalities, these were noted only after knowledge of the FDG-PET findings. Our experience reveals that anatomic and metabolic abnormalities can be found in children who exhibit autistic behavior. An FDG-PET study may provide evidence of metabolic dysfunction after an initially unremarkable MRI scan because subtle anatomic abnormalities (as those seen with neuronal migrational anomalies) may be found only after knowledge of a regional metabolic abnormality.

Pilocytic astrocytoma: correlation between the initial imaging features and clinical aggressiveness.

OBJECTIVE: Astrocytomas are classified as either fibrillary or pilocytic on the basis of their histologic appearance. The imaging features of the fibrillary astrocytoma correlate closely with the tumor's clinical aggressiveness and are, therefore, useful in predicting prognosis. Correlation between the imaging features and the clinical aggressiveness of the pilocytic astrocytoma, however, is not well established. Accordingly, we compared the initial MR and CT appearances of the lesion with tumor aggressiveness as seen clinically to determine if a correlation exists. MATERIALS AND METHODS: We retrospectively evaluated the initial MR images or CT scans of 32 consecutive patients who had a histologic diagnosis of pilocytic astrocytoma. The lesions were evaluated with regard to location, size, calcification, morphology, and degree of contrast enhancement. These initial imaging features were correlated with the aggressiveness of the tumor as seen clinically. Tumors were classified as aggressive or nonaggressive on the basis of their clinical manifestations. Patients with clinically aggressive lesions had progressive symptoms and radiologic evidence of tumor progression or recurrence within an unusually short period. Patients with clinically nonaggressive lesions had a more indolent course, either improving or remaining stable, on both clinical and radiologic evaluations. In 12 patients, the tumor was classified as aggressive clinically, either progressing or recurring within a median time of 7.5 months (range, 2.5-118 months) from the initial diagnosis. The remaining 20 patients had a clinically nonaggressive course. RESULTS: In our series of patients, lesion size and location were not significantly different between the nonaggressive and aggressive tumors, as noted clinically. Furthermore, the aggressive and nonaggressive tumors were similar with regard to the presence or absence of calcium. Most tumors in both groups showed either moderate or marked enhancement and were multilobular. CONCLUSION: The initial CT and MR features of pilocytic astrocytoma are unreliable for predicting which lesions will behave in a more aggressive manner clinically and have a poor prognosis.

Dorsal third ventricular cyst: an entity distinct from holoprosencephaly.

The treatment and subsequent developmental progress of six children with dorsal third ventricular cysts are described. This cystic malformation has a radiological appearance which is superficially similar to that of the dorsal cyst of alobar holoprosencephaly, especially when the third ventricular cyst is large. Indeed, previous reports have identified this abnormality as a form of holoprosencephaly. However, careful study reveals that the dorsal third ventricular cyst is a distinct entity both developmentally and clinically. The six patients in this series were effectively treated with shunts, and their subsequent developmental progress was assessed by means of the Prescreening Developmental Questionnaire-Revised as well as the Bayley Scales of Infant Development. The nomenclature and differences between this entity and the holoprosencephalies are reviewed. The authors conclude that dorsal third ventricular cysts have a developmental and clinical course more similar to that of arachnoid cysts than to that of the holoprosencephalies.

Walker-Warburg syndrome.

The Walker-Warburg syndrome (WWS) is a rare autosomal recessive disorder characterized by lissencephaly, cerebellar and retinal malformations, and congenital muscular dystrophy. We report a new case of WWS identified with the aid of cranial MR and briefly review the radiologic findings of this lethal syndrome.

Inflammatory lesion mimicking a metastatic ependymoma.

A 2.5-year-old child who had undergone nearly total resection of an infratentorial ependymoma demonstrated a new enhancing lesion on the undersurface of the right cerebellar hemisphere 7 weeks after the initiation of adjuvant chemotherapy. The residual primary tumor demonstrated continued regression during chemotherapy, and magnetic resonance imaging of the spine and cytopathological examination of the cerebrospinal fluid showed no evidence for other sites of metastatic tumor. Because of the unusual anatomic and temporal characteristics of this lesion and despite radiographic criteria highly suspicious for a metastatic lesion, a biopsy was performed, revealing histological evidence of an inflammatory process.

Dysmyelinating leukodystrophies: "LACK Proper Myelin".

A mnemonic has been developed, "LACK Proper Myelin", which can serve as a spring board in developing a differential diagnosis in a child with a dysmyelinating leukodystrophy. Certain distinguishing features of the diseases can be used including laboratory evaluation, head size and sex of the child. The important common ground that all the dysmyelinating leukodystrophies share, they all are inherited disorders that have a enzymatic or biochemical abnormality resulting in the development of abnormal myelin.

False-positive CT gas cisternogram.

Nonfilling of the normal internal auditory canal on computed tomographic (CT) gas cisternography was observed in seven (11%) of 62 cases in a retrospective study of three series of gas cisternograms. The meatal surface of the fluid-filled canal was convex and pointed, simulating a small acoustic neuroma. A meniscus effect at the gas-cerebrospinal fluid interface was considered the probable cause of nonfilling of the canal with gas. Shaking the patient's head briskly after injection of gas into the spinal fluid will facilitate filling of the internal auditory canal with gas. Bone erosion in the canal or meatus suggests the presence of acoustic neuroma. In the absence of conclusive findings of neuroma, persistent nonfilling of the canal is an indication for repeat cisternography with an alternate contrast medium.

Range highlight facility within region of interest for air-CT cisternography and canalography.

Air-CT cisternography and canalography have improved the radiographic diagnosis of small acoustic neuromas. Institutions that do not have an Independent Viewing System with their CT unit can improve their technique by data manipulation using the Range Highlight Facility within the Region of Interest as a part of their existing commercial unit.

Noninvasive screening of extracranial carotid disease: duplex sonography with angiographic correlation.

Initial experience with a pulsed Doppler device coupled to a high resolution real-time sonographic scanner for noninvasive evaluation of extracranial carotid disease is reported. The primary objective was to evaluate patients with asymptomatic cervical bruits and/or equivocal histories of transient cerebral ischemia to determine which of them required further study with angiography. An assessment of the degree of extracranial carotid stenosis as well as the severity of atheromatous plaque formation was made and subsequently compared with the findings at angiography. During a 455 day period, a total of 501 patients were examined. In 150 arteries with complete angiography, correlation disclosed the noninvasive duplex technique to be 92% accurate in predicting which arteries would be significantly diseased. It is proposed that careful sonographic investigation of the extracranial carotid system is a safe and useful screening test for certain patients at risk for cerebrovascular accident.

Lumbar epidurography with metrizamide.

The results of 65 consecutive lumbar epidurograms obtained with metrizamide are reviewed. A pure Seldinger technique with a caudal approach through the sacral notch and selective nerve root sheath injection affords the best technical results. Lumbar epidurography serves as an important radiographic procedure in the evaluation of patients with equivocal myelography and/or confusing or nondiagnostic physical findings. It is particularly valuable in patients with a wide ventral epidural space secondary to previous surgery, arachnoiditis or congenital condition. This situation occurs most commonly at the L5-S1 disk space.

Upper thoracic extralobar pulmonary sequestration presenting with respiratory distress in a newborn.

An upper thoracic extralobar pulmonary sequestration in a newborn is presented. It was present on the initial chest radiograph taken because of respiratory distress. The sequestration was surgically removed and the infant's respiratory difficulties improved.

Metrizamide lumbar epidurography with Seldinger Technique through the sacral notch and selective nerve root injection.

Lumbar epidurography serves as an important radiographic procedure in the evaluation of patients with equivocal myelography and confusing or non-diagnostic physical findings. It is particularly valuable in patients with a wide ventral epidural space secondary to previous surgery, arachnoiditis or on a congenital basis. Several techniques and various contrast agents have been employed for the procedure. A pure Seldinger technique with a caudal approach through the sacral hiatus and injection of metrizamide gives excellent visualization of the epidural space and nerve root sleeves. The proper concentration of metrizamide is crucial for optimal results. Lateral, AP, and AP oblique radiographs, occasionally combined with lateral, complex motion tomography, clearly demonstrate the root sleeves and ventral epidural space. CT scanning, with present technology, does not provide the necessary detail for evaluating the epidural space.

Ultrasonographic features of pelvic lipomatosis.

The authors describe the diagnostic ultrasound findings of pelvic lipomatosis in a patient presenting with lower extremity thrombophlebitis. In this condition, ultrasound shows the full urinary bladder to assume a tubular or "cigar" shape and to "float" in the pelvic fat with failure to distend normally to the pelvic side walls. Confirmatory computed tomography discloses normal muscular and osseous anatomy but an increase in radiolucent fat surrounding the pelvic viscera. Clinical and radiographic findings are reviewed, and a differential diagnosis is presented.

Acute hemiplegia of childhood.

Acute hemiplegia of childhood is briefly reviewed with examples of various etiologies. The role of brain scans in diagnosing and following children with this syndrome is emphasized. Cerebral angiography and computer tomography represent complementary examinations in the evaluation of these patients.