Parenchymal Volume Loss Research Articles

Contribution of the cerebellum to neuropsychological functioning: Evidence from a case of cerebellar degenerative disorder

A detailed neuropsychological evaluation was performed on a patient with an idiopathic cerebellar degenerative disorder. Significant deficits were found in verbal and nonverbal intellegence, verbal associative learning, and visuospatial skills. These deficits were not readily explained by motor control difficulties. In contrast to the patient's moderately impaired language abilities, he was severely impaired on a test of verbal fluency and demonstrated mild naming deficits. Severe cerebellar parenchymal volume loss was demonstrated by magnetic resonance examination. Supratentorial structures showed only minimal posterior parietal and occipital sulcal prominence. On neurological examination, this patient had signs of severe involvement of the cerebellar systems and mild-to- moderate dysfunction of the corticospinal tract. As is characteristic of patients with cerebellar degeneration, there was neurophysiological evidence of subclinical involvement of auditory and somatosensory pathways at the level of the brain stem. Since relatively little cerebral cortical atrophy was noted in this patient, these findings suggest that an intact cerebellum is important for normal cognitive functions.

Pediatric AIDS: Comparative cranial MRI and CT scans

Fourteen consecutive children (age range: 4 months to 11 years; median: 4 years) with acquired immunodeficiency syndrome (AIDS) were studied prospectively with cranial magnetic resonance imaging (MRI) and unenhanced computed tomography (CT). In 4 children, human immunodeficiency virus infection was transfusion-related, while in 10, transplacental transmission occurred. Twelve children had abnormal neurologic examinations; of these, 10 had developmental delay and 2 were normal by developmental history and neurologic examination. Standardized neuropsychologic tests were given to all children; 5 were in the normal range and 9 demonstrated significant delays in verbal or motor/perceptual development. All children with abnormal neuropsychologic results were developmentally delayed; however, in 2 infants with normal neuropsychologic assessments, developmental delay and abnormal neurologic examinations were documented. Brain parenchymal volume loss (8 patients) and cervical lymphatic hypertrophy (4 patients) were demonstrated equally well by MRI and CT. CT alone demonstrated striatal-thalamic calcification (1 patient), whereas MRI alone demonstrated delayed myelination (1 patient). The extent of focal white matter lesions in 1 patient was demonstrated better by MRI than by CT. No intracranial mass lesions were demonstrated; however, significant correlations were found between peripheral volume loss imaged by either MRI or CT and both verbal and performance scores. In our small series, MRI offered no apparent advantage over CT in evaluating children with AIDS. We suggest that CT alone is sufficiently sensitive in evaluating pediatric AIDS-related brain abnormalities.

Neonatal schizencephaly: Comparison of brain imaging

Schizencephaly is a regional disturbance of cerebral hemisphere formation occurring at 3–5 months gestation; neonatal presentation is uncommon. Three neonates with schizencephaly were evaluated with cranial ultrasonography (US), unenhanced computed tomography (CT), and magnetic resonance imaging (MRI) examinations. Common findings in US, CT, and MRI include parasylvian and midline clefts, size asymmetries of the basal ganglia and thalamus, cerebral parenchymal volume loss, ventriculomegaly, ventricular diverticular, and absence of the septum pellucidum. MRI and CT were superior to US in detecting calcification, gyral and sulcal abnormalities, and parasylvian clefts. MRI alone demonstrated homolateral absence of the sylvian vasculature, small medullary pyramids, low position of the fornix, and the thinning of the corpus callosum. Although US appears adequate as a screening test, MRI best defines the precise pathoanatomic findings of neonatal schizencephaly and allows for the prediction of neurologic outcomes in affected newborns.

Leptomeningeal metastasis

We evaluated 14 consecutive patients with leptomeningeal metastasis prospectively, using both T1-weighted (T1W) gadolinium-DTPA-enhanced MR (Gd-MR) and contrast-enhanced CT (CE-CT). Thirteen had positive CSF cytology; the remaining patient had an atypical CSF lymphocytosis and primary CNS lymphoma. The patients (8M/6F) ranged in age from 8 to 70 years (median, 42 years). Tumor histology included 3 systemic and 2 primary CNS lymphomas, 3 breast carcinomas, 2 leukemias, 1 malignant schwannoma, 1 small cell lung cancer, 1 prostate cancer, and 1 melanoma. Both imaging methods demonstrated parenchymal volume loss equally well in all patients. Gd-MR revealed abnormal enhancement of meninges or parenchyma in 10 patients, including all 5 patients with positive CE-CT. Neither technique revealed any foci of abnormal enhancement in 4 patients. Gd-MR was superior to CE-CT in demonstrating and quantifying enhancing subarachnoid and parenchymal nodules in 6 patients and in demonstrating sulcal, dural, cisternal, tentorial, and ependymal enhancement. Our findings indicate that T1W Gd-MR is the preferred imaging modality in leptomeningeal metastasis and suggest that CE-CT is unnecessary.