Don A. Wilson

MR Imaging Determination of the Location of the Normal Conus Medullaris Throughout Childhood

This retrospective study was designed to determine the location of the conus medullaris in normal children by reviewing a series of MR images of the lumbar spine. The study group consisted of 184 children ranging in age from newborn to 20 years who had a normal conus level as reported by the radiologist of record. The range of conus levels for the entire group of normal children was T12 to L3. The range for the 0-2-year-old group was T12 to L2-L3 with an average of L1-L2. The range of conus levels for the 19-20-year-old group was L1 to L2 with an average of L1-L2. We conclude that the conus medullaris does not ascend throughout childhood as stated by previous authors but attains the adult level sometime during the first few months of life. A conus level at L2-L3 or above should be considered normal at any age. A conus level at L3 is indeterminate, since it is possible for a normal or a tethered conus to be located at this level.

Quantitative Morphometric Analysis of Brain Growth Using Magnetic Resonance Imaging

Using a simple image analysis system, we have established normative data obtained from magnetic resonance imaging (MRI) scans for the relative size and growth of the major structural domains of the brain. Midsagittal scans of the head were analyzed in 95 subjects aged 0 to 20 years. Only scans with no demonstrable structural abnormalities of the brain were utilized. Age-related changes in the relative growth of specific structures were calculated by dividing patients into 5-year age increments. No age-related changes were found in the size of the posterior fossa, supratentorial intracranial space, or cisterna magna relative to the total intracranial vault space. A significant (P < .01) increase in the size of the corpus callosum relative to that of the supratentorial structures and relative to the total intracranial vault space was noted to occur between the 6- to 10-year-old and 11- to 15-year-old age groups. This may reflect an increase in myelination of the corpus callosum that occurs during this period. A small reduction in the ratio of the posterior fossa to the supratentorial space was found between the 0- to 5-year-old and the 6- to 10-year-old age groups, but the biological significance of this difference is uncertain. It appears from these data that quantitative analysis of MRI scans can be used to draw objective conclusions about the relative sizes and growth of the major brain structures. The development of normative data for these structures and the simplicity of the methodology should have many clinical applications in the assessment of aberrant brain development. (J Child Neurol 1990;5:127-130).

Ultrasound Diagnosis of Hydrocolpos and Hydrometrocolpos

Two neonates, one with hydrocolpos and one with hydrometrocolpos, were studied with ultrasound. In each case a primarily cystic abdominal mass arose from the pelvis but contained internal echoes. It is concluded that ultrasound evaluation of these disorders should aid in the preoperative diagnosis.

Reversible posterior leukoencephalopathy syndrome in children undergoing induction therapy for acute lymphoblastic leukemia

We present three cases of children with acute neurologic changes while undergoing induction chemotherapy for acute lymphoblastic leukemia (ALL). These cases fall into the spectrum of reversible posterior leukoencephalopathy syndrome (RPLS), including abrupt alterations in mental status, headache, seizures, visual changes, hypertension, and characteristic findings on magnetic resonance imaging. Although the underlying mechanism of RPLS is still under investigation, the appropriate treatment and management of the acute event is becoming clearer. Early treatment of hypertension, control of seizure activity, and withdrawal of inciting agents can lead to rapid reversal of symptoms and return to baseline functioning. Pediatr Blood Cancer 2007;49:198–203.

Parainflammator Leukoencephalomyelitis: Clinical and Magnetic Resonance Imaging Findings

Parainflammatory leukoencephalomyelitis is a broad term used to include the spectrum of disorders that affect the central nervous system following infection, immunization, or other noxious stimuli. There is a wide range of clinical and pathologic severity, ranging from acute cerebellar ataxia to acute hemorrhagic leukoencephalopathy. With the improved survival of these patients, magnetic resonance imaging provides a window to the pathologic process, which can aid in the long-term management of these patients. Although lesions of the brainstem and spinal cord correlate well to clinical symptoms, multiple cortical lesions may be present without specific localizing signs. The distribution of magnetic resonance lesions is different from that commonly seen in multiple sclerosis. In some cases, prolonged immunosuppression may be required to prevent recrudescence of the inflammatory response. (J Child Neurol 1988;3:205-213).

Neuroimaging Findings in Alexander's Disease

We present the findings from magnetic resonance imaging, computed tomographic scan, and single photon emission computed tomography of the brain in a 2-year-old girl with Alexanders disease. Computed tomographic scans showed prominent low-density white matter throughout the cerebral hemispheres. Magnetic resonance imaging showed increased T2 signal from the cerebral white matter but not the cerebellum or brain stem. Single photon emission computed tomography revealed diminished cerebral metabolism, particularly in the frontal regions, as compared with the cerebellum. (J Child Neurol 1990;5:253-258).

Reversible Treatment-Related Leukoencephalopathy

We present two children with acute lymphocytic leukemia who developed leukoencephalopathy following administration of a combination of intravenous ara=C and methotrexate during the consolidation phase of chemotherapy. Cranial magnetic resonance imaging showed widespread, abnormally high signal intensity in the deep white matter in both patients, though one patient had normal cranial computed tomographic scan. Treatment was modified, symptoms resolved in 1 to 2 weeks, and the white-matter changes resolved over 6 to 12 months. Intravenous cytarabine and methotrexate appear to act synergistically to enhance the potential for central nervous system toxicity. Awareness of this potentially serious complication of chemotherapy can facilitate timely recognition of leukoencephalopathy with the use of magnetic resonance imaging. (J Child Neurol 1989;4:207-212).

Transfer function measurement and analysis for a magnetic resonance imager

The transfer function characteristics of a 1.5T imager have been determined. An edge response function (ERF) was obtained from a water/Plexiglas interface at various pixel widths ranging from 0.312 to 1.0 mm. An SE pulse sequence was used with a 5-mm transaxial slice. The ERF was smoothed, differentiated, and Fourier transformed to obtain MTF curves. The LSF was analyzed for skewness and kurtosis. The area under the MTF amplitude curves and the equivalent bandpass were calculated. All ERFs, LSFs, and MTFs were well behaved. The resulting LSF was Gaussian. All calculated MTFs had cutoff frequencies slightly less than the theoretical Nyquist limit. The MTF calculated from the theoretical Gaussian LSF is slightly superior to that calculated from experimental data and provides an upper limit to the MTF. Spatial resolution in our MR imager is dominated by the pixel size via the Nyquist sampling theorem. System performance is slightly less than theoretically predicted, possibly due to image processing algorithms during the reconstruction process.

Memory Deficits in a Demented Patient with Probable Corticobasal Degeneration

Anterograde and retrograde amnesia in a patient with probable corticobasal degeneration (pCBD) and dementia were studied in a university medical center setting. The patient with pCBD and four comparison patients of comparable global mental status (Mini-Mental State Exam) who met NINCDS-ADRDA criteria for Alzheimers disease (AD) were included. Standard neuropsychological tests of naming, intelligence, achievement, verbal fluency, anterograde and remote verbal and visuospatial memory, and motor skill learning were given. The pCBD patient exhibited a progressive asymmetric akinetic-rigid syndrome, which was unresponsive to Sinemet. His initially mild, intellectual deficits consisted of apraxia, slowed speech, and word-finding and memory difficulties. Over a 2-year period, a dementia syndrome developed, which involved more-serious deficits in praxis and naming, as well as impairments in spelling, calculation, verbal fluency, IQ, anterograde verbal and visuospatial memory, and motor skill learning. When tested by recall methods, the pCBD patient exhibited marked deficits on several tests of remote memory; however, on recognition testing, he performed normally on the Famous Faces Test and on a test of geographical knowledge, which measures remote visuospatial memory. By contrast, the four AD patients, who showed equivalent naming difficulties, less-severe fluency deficits, and normal motor skill learning, showed severe impairments in recalling and recognizing the names of famous people from photographs. A magnetic resonance imaging (MRI) scan of the pCBD patient showed marked frontal and parietal lobe atrophy and central atrophy, with ventriculomegaly that was greater on the left side of the brain. The temporal lobes were relatively spared, and the amygdalae, hippocampi, and temporal horns were of normal size. The striking integrity of the pCBD patients remote recognition memory can probably be accounted for by the absence of atrophy of medial temporal lobe structures, especially the hippocampus, which undergo degenerative changes early in the course of AD. Alternatively, differences in the extent of damage to the temporoparietal cortices may explain the remote-memory differences between the pCBD and the AD patients.

Piano playing in Alzheimer's disease: Longitudinal study of a single case

Abstract Preserved musical performance by patients with Alzheimers disease (AD) has been attributed to an intact system for implicit musical cognition which may be localized in the right hemisphere. To examine this idea more thoroughly, we studied patient ML, a woman with AD who learned to play the piano as a child. Over three yearly evaluations, ML exhibited progressive deterioration in the following domains: language, visuospatial functions, attention, sequencing, picture priming, recognition of familiar songs, and discrimination of rhythm, meter, transposition, and major from minor keys, but pursuit rotor learning remained intact. By the third year of testing, ML also exhibited severe limb apraxia, but showed only subtle losses in the quality of her piano playing of familiar songs. She also showed immediate and accurate transfer of her playing skill from the piano to the xylophone. Preserved musical performance in AD seems to depend on circuits involving the basal ganglia, cerebellum and motor areas o...