Cine magnetic resonance imaging and color Doppler flow mapping in infants and children with pulmonary artery bands

Cine magnetic resonance imaging (MRI) and color Doppler flow mapping were performed in 12 infants and children (aged 3 to 35 months) after pulmonary artery banding to define the anatomy and physiology of the right ventricular outflow tract and evaluate the anatomy. MRI was performed using a 1.5 Tesla magnet in the sagittal, axial and oblique views with all patients studied in the 24 cm head coli following adequate sedation. High-resolution cine MRI was obtained in all patients and the narrowest flow diameter on cine MRI correlated well with the pressure gradient measured across the band in 11 patients at cardiac catheterization or surgery (r = -0.95). Signal loss was always seen distal to the band associated with turbulent flow as seen by color Doppler flow mapping. Signal loss in cine MRI was also seen proximal to the band. The length of this proximal signal void also correlated well with the pressure gradient measured across the band (r = 0.91) and was closely matched by the zone of proximal spatial acceleration defined by digital computer analysis of color Doppler flow map images (r = 0.89), which also demonstrated low grade variance associated with the laminar accelerating flow stream. The position of the band was accurately defined by cine MRI which identified inadequate pulmonary artery banding in 2 patients confirmed subsequently at cardiac catheterization and angiography. Cine MRI and color Doppler flow mapping when used together provide high-resolution detail about the right ventricular outflow tract and pulmonary artery band anatomy and function.(ABSTRACT TRUNCATED AT 250 WORDS)

MR imaging of the corpus callosum

The corpus callosum is the major axonal commissure of the brain, connecting the two cerebral hemispheres and providing communication between the cortical and subcortical neurons. With MR imaging in the sagittal plane, the corpus callosum can be depicted in great detail. We review the normal anatomy, development, and process of myelination of the corpus callosum. The MR features of various pathologic conditions involving the corpus callosum are described. Finally, we discuss the evolving role of MR imaging in neuropsychiatric diseases with respect to the corpus callosum.

Magnetic resonance imaging morphometric analysis of cerebral volume loss in human immunodeficiency virus infection. The HNRC Group

Magnetic resonance imaging was used to compare male subjects seropositive for antibody to human immunodeficiency virus type 1 (HIV positive), with and without medical symptoms, with two groups of men who were seronegative (HIV negative). The control subjects included men at high risk for exposure to HIV-1 and those at low risk. None of the HIV-positive subjects met criteria for HIV-associated dementia or had detectable opportunistic brain disease. Quantitative image-analytic techniques were used to estimate volumes of ventricular and cortical cerebrospinal fluid, cerebral white matter, and cortical and subcortical gray matter structures. Relative to low-risk group control subjects and asymptomatic HIV-positive subjects, nondemented but medically symptomatic HIV-positive subjects showed significant increases in cerebrospinal fluid, reduced volume of cerebral white matter, and reduced cerebral gray matter volumes. Unexpectedly, however, some cerebrospinal fluid increases and gray matter volume decreases were present in the seronegative high-risk control subjects as well.

Cerebral morphologic distinctions between Williams and Down syndromes

Neurobehavioral studies of Williams syndrome (WS) and Down syndrome (DS) have revealed distinct profiles of cognitive strengths and weaknesses. In a previous report, we described several gross brain morphologic distinctions on magnetic resonance images between these two disorders. While the observed cerebral hypoplasia was of equal degree in the two groups, cerebellar size was entirely normal in the subjects with WS but dramatically reduced in subjects with DS. In WS, paleocerebellar vermal lobules subtended a smaller area on midsagittal sections, but neocerebellar lobules were actually larger. These results suggested important distinctions between WS and DS in terms of the action and anatomic targets of factors that alter brain development in these syndromes. The present study extends the earlier findings by focusing in detail on the morphologic features of the cerebral hemispheres, particularly cerebral gray matter. The results suggest that some frontal and temporal limbic structures are relatively preserved in WS, while some basal ganglia and diencephalic structures are relatively preserved in DS.

Fetal alcohol syndrome: a case report of neuropsychological, MRI and EEG assessment of two children

Neuropsychological, neuroanatomical, and electrophysiological data are presented on two subjects with fetal alcohol syndrome (FAS). Both boys had intelligence quotients in the mentally deficient range and were found to have several other severe, specific deficits. Magnetic resonance imaging showed abnormalities of the corpus callosum, and reductions in the size of the basal ganglia and thalamic structures. No focal abnormalities were noted in the electroencephalogram records, although the electroencephalograms of both boys were moderately abnormal for their age group. A multidisciplinary approach to the study of FAS, hopefully will lead to a more unified concept of the disorder and perhaps indicate specific areas of vulnerability.

Specific neurobehavioral profile of Williams' syndrome is associated with neocerebellar hemispheric preservation

Previous work demonstrated enlargement of the neocerebellar vermis in Williams' syndrome (WS), despite diminished volumes in the cerebral hemispheres. We present the first in vivo volumetric study of any structure within the cerebellar hemispheres. Using MRI, we identified and reliably measured the neocerebellar tonsils in WS subjects; Down's syndrome (DS) subjects matched for age, IQ, and cerebral volume; and age-matched normal controls. WS tonsils were equal in size to control tonsils and larger than DS tonsils. In proportion to the cerebrum, WS tonsils were larger than controls'. These results coincide with the remarkable neuropsychological preservation of language and affect in WS, despite general cognitive impairment. They contrast with the neocerebellar vermal hypoplasia seen in autism, with its communicative and affective deficits. Additionally, two WS subjects showed Chiari type I malformations, but the average tonsillar position in WS was not found to be different than in controls.

Callosal morphology concurs with neurobehavioral and neuropathological findings in two neurodevelopmental disorders

To integrate neuroimaging, neuropathologic, and neuropsychological findings, computer-assisted morphometry was applied to magnetic resonance images of the corpus callosum in adolescents with Down and Williams syndromes and in control subjects. Callosa of subjects with Down syndrome were distinctively rounded in form, consistent with Down syndrome brachycephaly. These callosa also showed decreased widths throughout their rostral fifth, which serves frontal lobe projections. This finding correlates with the hypocellularity and hypofrontality of neocortex in subjects with Down syndrome and with their neuropsychological profile of frontal lobe dysfunction. Callosa of subjects with Williams syndrome generally resembled control specimens, in congruence with their frontal lobe structure and better preserved frontal lobe function. These results represent a convergence of findings across levels of neuroscientific investigation.

MR findings in acute and chronic coccidioidomycosis meningitis

PURPOSE

To characterize MR findings in acute and chronic coccidioidomycosis meningitis and relate the imaging features to the clinical course.

METHODS

We reviewed MR scans and clinical findings of 12 patients with coccidioidal meningitis.

RESULTS

Patients with active or untreated disease were found to have hydrocephalus and intense enhancement of the cervical subarachnoid space, basilar, sylvian, and interhemispheric cisterns on postcontrast MR scans. Focal parenchymal signal abnormalities suggesting ischemia or infarction were common. Abnormal MR enhancement decreases during therapy, although patients develop cortical and/or brain stem atrophy.

CONCLUSIONS

Widespread cisternal and cervical subarachnoid meningeal involvement is common in coccidioidal meningitis. Serial contrast MR imaging reflects the effects of therapy in patients with coccidioidal meningitis.

Incidence of AIDS dementia in a two-year follow-up of AIDS and ARC patients on an initial phase II AZT placebo-controlled study: San Diego cohort

In a prospective study to determine the incidence of clinical dementia in patients with AIDS and ARC, 29 men and 3 women, 19 with ARC and 13 with AIDS, were examined neurologically and neuropsychologically every 6 months for 2 years during a placebo-controlled zidovudine (AZT) licensing trial. Most received two MRI brain scans. Although no patient was clinically demented at baseline, 9 (28%) developed dementia during the 2 years. Progression to dementia was associated with neuropsychological deterioration and with worsening on MRI during a preceding 6-month period, but not with baseline treatment group assignment. The results suggest that patients at CDC Stage IV who do not receive antiretroviral treatment earlier in their illness may develop clinical dementia at an annual rate of about 14%.

Magnetic resonance imaging of AIDS-related polyradiculopathy

AIDS-related polyradiculopathy is a syndrome associated with cytomegalovirus infection. We report two cases of AIDS-related polyradiculopathy in which spinal T1-weighted MRI with gadolinium-DTPA showed enhancement of the pial lining of the conus medullaris, cauda equina, and lumbar nerve roots. Both patients clinically improved with ganciclovir treatment.

Magnetic resonance imaging abnormalities in lenticular nuclei and cerebral cortex in schizophrenia

Neuropathologic and brain imaging studies have produced evidence of brain abnormalities in schizophrenic patients, often within the cerebrum's limbic lobe, and, less frequently, within basal ganglia. In the present study we used magnetic resonance imaging morphometric techniques to estimate volumes of specific cerebral structures in schizophrenic patients and age- and sex-matched normal controls. Estimates of the volume of mesial temporal lobe structures were reduced and estimates of the volume of the lenticular nucleus were increased in the schizophrenic patients. There was also evidence of reduced cranial volume in some schizophrenics. The magnitude of the lenticular abnormality, but not the temporal lobe abnormality, was associated with age at first psychiatric contact; earlier onset was associated with larger lenticular nuclei. The possible relevance of these results to neurodevelopmental hypotheses about the pathogenesis of schizophrenia is discussed.

Maturation of human cerebrum observed in vivo during adolescence

In the present study using magnetic resonance imaging (MRI), age changes in the morphology of the cerebral cortex, greatest in the frontal and parietal convexities, were observed during adolescence. Results suggest that increases in cerebrospinal fluid (CSF) within the sulci of these cortical regions accompany grey matter decreases. Smaller reductions in volume are also observed in subcortical grey matter nuclei. These apparent grey matter volume reductions presumably reflect processes of late brain maturation. The changes may be related to decreasing neural plasticity.

Cerebral structure on magnetic resonance imaging in language- and learning-impaired children

Using magnetic resonance imaging 20 language- and learning-impaired children were compared with 12 normal control subjects. Gross brain structure was remarkably normal in the language- and learning-impaired group. Semiautomated morphometry was used to measure hemispheric volumes and cerebral asymmetries in six cerebral regions. The volume of the left posterior perisylvian region was significantly reduced in language- and learning-impaired children. Asymmetries in inferoanterior and superoposterior cerebral regions were also significantly different in this group. Results of descriptive group comparisons of estimated volumes of other cerebral gray-matter structures raise the possibility that some language- and learning-impaired children may have additional volume reductions in cortical and subcortical structures. The results suggest that hemispheric specialization of function may be anomalous in this population.

Improved detection and delineation of head and neck lesions with fat suppression spin-echo MR imaging

To compare conventional and fat suppression MR imaging in their ability to detect head and neck lesions, we prospectively studied 17 patients with head and neck tumors and one normal volunteer. Five patients had benign tumors (one mixed cell tumor, one hemangioma, one lipoma, and two plexiform neurofibromas), 10 had malignant tumors (six squamous cell carcinomas, two minor salivary gland carcinomas, one lymphoma, and one malignant fibrous histiocytoma), and two had nonspecific lymphadenopathy. All subjects were studied with standard spin-echo T1- and T2-weighted images (T2-weighted imaging was done with and without fat suppression technique). In addition, T1-weighted images with contrast enhancement and fat suppression were obtained in nine patients. A four-point grading system was used for comparison of the conventional and fat suppression images. Grades ranged from 0 (unsatisfactory, the lesion cannot be seen) to 3 (excellent, the lesion and its margins can be seen clearly with sharp contrast from surrounding normal tissue). We found that postcontrast fat suppression T1-weighted images and fat suppression T2-weighted images were most useful; these sequences obtained an average score close to grade 3 (2.77 and 2.85, respectively). On the other hand, the conventional T2-weighted images had an average score of about 2 (1.82) and the conventional T1-weighted image had a score of about 1 (1.33). Fat suppression T2-weighted sequences generally were superior in cases of lymphadenopathies. Postcontrast T1-weighted images were most useful in a case of plexiform neurofibroma, owing to their fibrous component and lower proton density.(ABSTRACT TRUNCATED AT 250 WORDS)

Intra- and paraorbital lesions: value of fat-suppression MR imaging with paramagnetic contrast enhancement

The orbital area of 18 individuals was examined by using a combination of fat-suppression contrast-enhanced MR imaging to determine whether contrast between fat and surrounding tissues could be improved over that obtained with conventional fat-suppression techniques alone. We used a hybrid technique combining two independent methods of fat suppression. Subjects consisted of 16 patients and two normal volunteers. Fifteen individuals received gadopentetate dimeglumine, and conventional T1-weighted, T2-weighted, and fat-suppression T1-weighted images were obtained. The fat-suppressed T1-weighted images obtained after contrast administration provided more information than did the conventional MR images. Intraorbital and paraorbital lesions could be distinguished easily from intraorbital fat that had been suppressed. Cases of chorioretinitis and optic neuritis could be confidently diagnosed only by this technique. Cases of optic nerve meningioma and mixed conal lesions also were better appreciated. Because of sharp contrast between tissue planes, this technique was helpful for detecting any intraorbital invasion from paraorbital lesions. Fat-suppression MR imaging with paramagnetic contrast enhancement can significantly improve the delineation of both normal and abnormal structures and better define lesional margins in the orbit, where large amounts of fat are present. Our results support earlier findings, and we suggest that postcontrast fat-suppressed T1-weighted imaging be used instead of conventional T1-weighted postcontrast imaging in evaluating orbital and paraorbital lesions.

Cerebral structure on MRI, Part II: Specific changes in Alzheimer's and Huntington's diseases

Using magnetic resonance (MR) imaging and morphometric techniques, groups of patients with Alzheimer's disease (AD) and Huntington's disease (HD) were compared with a large group of normal control subjects. Measures of volume loss in specific subcortical nuclei and eight cortical regions as well as an index of white matter abnormality were obtained. Results indicated expected widespread cortical volume reductions in AD, which were especially severe in mesial cortices; but comparable reductions were present in subcortical structures, particularly the thalamus. In HD, the greatest reductions were in striatal structures, but significant abnormalities were also detected in the thalamus and inferior cortical areas, especially in mesial temporal lobe structures. Significant degeneration in white matter was present in both groups, but was more dramatic in the HD patients. The significant diencephalic reduction in AD may make an important contribution to early memory deficits in the disorder, which are usually attributed to hippocampal damage. Similarly, damage to both the thalamus and mesial temporal lobe structures may play a role in the memory deficits of HD.

Cerebral structure on MRI, Part I: Localization of age-related changes

In this report, earlier findings of age-related changes in brain morphology on magnetic resonance (MR) images are extended to include measurements of individual cerebral grey matter structures and an index of white matter degeneration. Volumes of caudate, lenticular, and diencephalic structures are estimated, as are grey matter volumes in eight separate cortical regions. Results suggest that between 30 and 79 years significant decreases occur in the volume of the caudate nucleus, in anterior diencephalic structures, and in the grey matter of most cortical regions. The data suggest that the volumes of the thalamus and the anterior cingulate cortex may be unchanged. Among those cortical regions found to be affected in aging, some evidence is present for greater change in association cortices and mesial temporal lobe structures. There are also dramatic age-related changes in the white matter, manifest as lengthened T2 values on MR images.

Intracranial cryptococcosis in immunocompromised patients: CT and MR findings in 29 cases

CT and MR scans of 29 immunocompromised patients (28 with AIDS or ARC, one with diabetes mellitus) who had documented intracranial cryptococcal infection were reviewed retrospectively. All patients had CT studies; 26 received iodinated contrast agent. CT findings included normal results in nine of 29, atrophy only in 13 of 29, nonenhancing lesions in three of 29, enhancing lesions in two of 20, and foci of leptomeningeal calcification in two of 29. Ten patients had both CT and MR studies, and four received gadopentetate dimeglumine. Among these 10 patients, five had normal CT studies and one showed moderate central atrophy. All 10, however, had abnormal MR findings. We observed four patterns: (1) parenchymal cryptococcoma (3/10); (2) numerous clustered tiny foci that were hyperintense on T2-weighted images and non-enhancing on postcontrast T1-weighted images, located relatively symmetrically in the basal ganglia bilaterally and in midbrain, representing dilated Virchow-Robin spaces (4/10); (3) multiple miliary enhancing parenchymal and leptomeningeal nodules (1/10); and (4) a mixed pattern, consisting of dilated Virchow-Robin spaces with mixed lesions such as cryptococcoma and miliary nodules (2/10). In the group of six patients with dilated Virchow-Robin spaces (patterns 2 and 4), two received gadopentetate dimeglumine, but the Virchow-Robin space lesions did not enhance; among the remaining four patients, two received gadopentetate dimeglumine (one with pattern 1 and one with pattern 3) and the lesions did enhance. Three patients in our study subsequently died and autopsies were performed. The postmortem results revealed dilated Virchow-Robin spaces filled with fungi in the basal ganglia, which correlated well with MR findings.(ABSTRACT TRUNCATED AT 250 WORDS)

MR imaging of vertebrobasilar vascular disease

Sixteen patients with vascular lesions of the vertebral and basilar arteries were studied with magnetic resonance imaging. The vascular abnormalities included seven cases of atherosclerotic disease with partial or complete thrombosis, six aneurysms, two cases of vertebrobasilar dolichoectasia, and one basilar artery dissection. Magnetic resonance effectively demonstrated vascular thrombosis with occlusion as high signal intensity on spin echo (SE) sequences with absence of flow void and no flow enhancement on gradient echo (GRE) images. Nonthrombosed aneurysms exhibited mixed signal intensity on SE images and hyperintensity on GRE images. Intraluminal thrombus also appeared heterogeneous, with variable signal intensity depending on the specific components of hemorrhage present. Correlation of the SE and GRE scans was helpful for distinguishing stasis and turbulent flow from thrombus. Compression of cranial nerves by vascular structures was clearly depicted in both cases of dolichoectasia. Basilar artery dissection was displayed as a focal area of flow void surrounded by a thrombosed false lumen. Magnetic resonance is an effective noninvasive method for evaluating vascular pathology of the vertebrobasilar system.

Magnetic resonance imaging in the evaluation of vitreoretinal disease in eyes with intraocular silicone oil

Media opacification in eyes filled with silicone oil makes the evaluation of recurrent retinal detachment difficult. Ultrasonography through silicone oil is subject to significant imaging artifacts. We performed magnetic resonance imaging on six patients with unilateral intravitreal silicone oil to determine if the technique would detect detached retina and subretinal oil. All patients had undergone pars plana vitrectomy with silicone oil injection for proliferative vitreoretinopathy; five patients had encircling solid silicone scleral buckles. In five patients the media were clear, and ophthalmoscopic findings were correlated with magnetic resonance findings. Four patients had recurrence of inferior retinal detachment; magnetic resonance imaging demonstrated subretinal oil in three of these patients. One patient had a concentric, shallow, anterior retinal detachment; magnetic resonance scanning demonstrated a globular hyperintensity suggestive of subretinal oil. In the sixth patient, who had an opaque cornea, magnetic resonance imaging suggested that the retina was attached preoperatively; this was confirmed at subsequent surgery. A chemical shift artifact was helpful in defining the contour of retinal detachments and the presence of subretinal oil by outlining the silicone oil within the eye.

Prenatal diagnosis of a craniopharyngioma using ultrasonography and magnetic resonance imaging

We report an infant with a craniopharyngioma which was detected in utero. Maternal uterine ultrasonography, done at 27 weeks because of polyhydramnios, revealed a 4 cm midline mass near the base of the fetal skull. At 31 weeks, magnetic resonance imaging of the maternal abdomen confirmed the presence of a mass in the region of the third ventricle and revealed hydrocephalus. Two days post-partum a computed tomography (CT)-guided needle biopsy of the mass was performed and recovered tissue which was histologically consistent with a craniopharyngioma. The infant's postnatal period was complicated by seizures, which were treated with phenobarbital, and by progressive hydrocephalus, necessitating placement of a ventriculo-peritoneal shunt. He also received therapy for central hypothyroidism and diabetes insipidus. The infant's parents refused permission for attempted resection of the tumour and he died at 8 weeks of age. This represents the second reported case of an antenatally detected craniopharyngioma. Four other cases of different intracranial tumours have been detected in utero using ultrasound, with no reported survivors past 3 days of age. There is a uniformly poor prognosis of such infants, but earlier diagnosis and intervention may change this result.