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Biomedical subjects

D C Armstrong

Publications and source records attributed to D C Armstrong.

28 records · Page 2Linked to original sources
PubMed1993

Congenital malformations of the spine.

The radiology of the congenital malformations of the spine has undergone significant advancement with the advent of newer modalities including computed tomography and, in particular, magnetic resonance imaging. Correlation with etiology and pathologic findings has improved. Congenital malformations have been classified according to neurulation and disjunction failures (dorsal) and those with persistent neurenteric connections with notochordal splitting (ventral). The most important benefit of the current state of imaging is the accurate morphologic representation of the malformation provided for the surgeon.

Child↗
PubMed1993

Cervical spine subluxation associated with congenital muscular torticollis and craniofacial asymmetry.

The relationship between craniofacial asymmetry, congenital muscular torticollis, and cervical spine subluxation was examined in a study of 30 children who presented to our Craniofacial Program from 1987 through 1990. Twenty-six of the 30 patients had craniofacial asymmetry and muscular torticollis without true suture synostosis documented by head and neck CT scans. These 26 patients had positional skull molding with consistent flattening of the contralateral occipitoparietal region and the ipsilateral fronto-orbital region relative to the side of the torticollis. Thirteen of the 26 patients also were found to have a C1-C2 subluxation. C1 was rotated forward of C2 on the side contralateral to the muscular torticollis in 12 of 13 patients. None of the patients with subluxation had neurologic deficits or required spinal stabilization. Ophthalmologic evaluations demonstrated amblyopia (4 patients) and horizontal strabismus (1 patient), both thought to be coincidental, with no evidence of nystagmus in any case. Seven of the 26 patients required surgical therapy for their neck muscle tightness, while the remainder responded to physiotherapy. Only 2 of the 26 patients underwent cranio-orbital reshaping for correction of their upper face asymmetry. Recognition of cervical subluxation in patients with congenital muscular torticollis may help to explain residual head-neck posturing problems even after successful neck muscle therapy.

Birth Injuries↗
PubMed1992

Craniofacial skeletal measurements based on computed tomography: Part I. Accuracy and reproducibility.

Computed tomography (CT) is a useful modality for the management of craniofacial anomalies. A study was undertaken to assess whether CT measurements of the upper craniofacial skeleton accurately represent the bony region imaged. Measurements taken directly from five dry skulls (approximate ages: adults, over 18 years; child, 4 years; infant, 6 months) were compared to those from axial CT scans of these skulls. Excellent agreement was found between the direct (dry skull) and indirect (CT) measurements. The effect of head tilt on the accuracy of these measurements was investigated. The error was within clinically acceptable limits (less than 5 percent) if the angle was no more than +/- 4 degrees from baseline (0 degrees). Objective standardized information gained from CT should complement the subjective clinical data usually collected for the treatment of craniofacial deformities.

Adult↗
PubMed1992

Craniofacial skeletal measurements based on computed tomography: Part II. Normal values and growth trends.

Current diagnosis and surgical correction of craniofacial anomalies would benefit from accurate quantitative and standardized points of reference. A retrospective study was undertaken to define normal values for a series of craniofacial measurements and to evaluate the growth patterns of the craniofacial complex through axial computed tomography (CT). Fifteen measurements were taken from 542 CT scan series of skeletally normal subjects. The measurement values were then divided into 1-year age categories from 1 to 17 years, and into four age groups for those under 1 year of age. The normal range and growth pattern of measurement values for the cranial vault, orbital region, and upper midface are presented. The overall size of the cranio-orbito-zygomatic skeleton reaches more than 85 percent of adult size by age 5 years. The cranial vault grows rapidly in the first year of life but growth levels off early. The upper midface grows at a slower rate in infancy, but continues to grow later in childhood and early adolescence. Knowledge of the differential growth patterns and normal measurement values in the craniofacial region will help improve diagnostic accuracy, staging of reconstruction, precision of corrective surgery, and follow-up of patients.

Adolescent↗
PubMedDate not supplied

Comparison of SPECT, EEG, CT, MRI, and pathology in partial epilepsy.

Twenty children with partial epilepsy who had surgery between the ages of 4 1/2 months and 18 years were studied preoperatively with electroencephalography (EEG), computed tomography (CT), and technetium-99m hexamethylpropyleneamineoxime 99mTc-HmPAO single photon emission computed tomography (SPECT; 20 interictal, 4 postictal). Fourteen had magnetic resonance imaging (MRI). All had an epileptiform focus (12 unilateral, 8 predominantly unilateral) on EEG. The combination of interictal and postictal regional cerebral blood flow (rCBF) abnormalities alone correlated with EEG foci in 16 of 20 patients. Interictal rCBF abnormalities correlated with EEG foci in 14 of 20. CT findings correlated with EEG foci in 14 of 20. MRI findings correlated with EEG foci in 13 of 14. Pathology demonstrated tumor in 6, cortical dysplasia in 4, mesial temporal sclerosis in 3, Sturge-Weber in 2, cavernous hemangioma in 1, Rasmussen encephalitis in 1, porencephalic cyst and gliosis in 1, and cysts found at surgery (but normal histology) in 2. Interictal and postictal SPECT, EEG foci, and CT findings each correlated with the pathology site in 17, 19, and 15 patients, respectively. MRI correlated with pathology site in 13 of 14 patients. Postictal and interictal abnormalities of rCBF correlated with EEG and pathology as frequently as CT. In 5 patients with normal CT scans and in 1 with a normal MRI, postictal and interictal rCBF correlated with EEG and pathology results; however, these 6 patients all had abnormalities on CT or MRI. SPECT, therefore, may be considered a valuable additional diagnostic procedure in the evaluation of epilepsy surgery candidates in that it adds to the evidence of abnormality at the involved site.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Chronic focal encephalitis (Rasmussen syndrome): six cases.

Six of 81 (7.4%) patients with medically intractable epilepsy treated by selective cortical excision at The Hospital for Sick Children, Toronto, Canada, since 1974 were found to have inflammatory changes in the excised specimens of cerebral cortex. The clinical and histopathological findings in these cases resemble the chronic encephalitic syndrome described by Rasmussen. We confirm the unsatisfactory seizure control and the guarded neurological and intellectual prognosis that has been associated with Rasmussen syndrome.

Adolescent↗
PubMedDate not supplied

Melanotic neuroectodermal tumor of infancy: clinical, radiologic, and pathologic findings in five cases.

Five pathologically proved melanotic neuroectodermal tumors of infancy are reported. These rare neoplasms of infancy exhibit a distinct predilection for the maxillary bone. Three tumors originated in the maxilla, one in the calvaria, and one in the cerebellar vermis. Those occurring in bone did not metastasize but were locally invasive, as reflected in their radiologic appearance. Bone erosion, expansion, hyperostosis, and osteogenesis can occur in the same neoplasm and were appreciated best on CT. MR imaging showed the soft-tissue component and extent of the neoplasm better than CT did. The pathologic findings from all five cases (and one possibly related melanotic tumor of the face) revealed abundant melanin. MR imaging of two melanotic tumors showed isointense T1-weighted and slightly hyperintense T2-weighted signals. This appearance is contrary to that of most melanin-containing tumors, which exhibit enhanced T1 and T2 relaxation, and indicates that variables other than the absolute amount of melanin may determine the MR signal. Clinically, rapid neoplastic growth and excessive melanin production by the tumor cells caused facial disfigurement and visible blue black discoloration. All five melanotic neuroectodermal tumors were resected and the vermian tumor was also irradiated. Four of five children were well and free from disease 1 month to 7 years after resection. The calvarial tumor was incompletely resected and involved the underlying brain, eventually causing death. The clinical, radiologic, and pathologic features of melanotic neuroectodermal tumors of infancy are reviewed. Melanotic neuroectodermal tumors of infancy that involve bone can be diagnosed from the clinical and radiologic findings. Prompt diagnosis and surgical resection are essential for cure.

Cerebellar Neoplasms↗