Enlargement Of Cerebrospinal Fluid Spaces Research Articles

MRI in the assessment of cerebral injury and cerebroprotective effects of renal denervation in resistant hypertension

The purpose of this single-centre, prospective, comparative study was to evaluate the pattern and severity of the brain structural changes in patients with resistant hypertension based on MRI assessments and their changes one year after renal denervation.Material and Methods. The study comprised 53 patients with resistant hypertension (RH), aged 52.1 ± 9.1 years, who underwent renal denervation (RDN) following the Good Clinical Practice guidelines. Patients underwent office blood pressure measurements, 24-hour blood pressure monitoring (BPM), and brain MRI scanning. Using brain MRI, the cerebrospinal fluid (CSF) system measurements, the presence and severity of periventricular white matter lesion and focal changes in the brain white matter were evaluated.Results. Initially, patients with RH had a high incidence of the structural brain alterations: 43 (81%) patients with fine focal brain lesions, 43 (81%) patients with enlarged CSF spaces, and 48 (90%) patients with periventricular white matter lesions. After renal denervation, a significant hypotensive effect was noted. According to brain MRI, the number of patients without enlarged CSF spaces did not change significantly: 15 (25%) patients initially, and 12 (20%) patients a year later (χ2 = 0.63, р = 0.43 и χ2 = 0.72, р = 0.40). The incidence of periventricular white matter lesion did not significantly change one year after RDN; however, the incidence of fine focal brain lesions significantly decreased in 21 patients (81% to 60%, p = 0.02).Conclusion. Thus, it has been revealed that patients with resistant hypertension are characterised by a high incidence of structural brain alterations based on MRI assessments. Bilateral renal denervation is followed by a significant decrease in the incidence of fine focal brain lesions, without a significant change in the cerebrospinal fluid volume one year after the procedure.

Magnetic resonance imaging findings of the posterior fossa in 47 patients with mucopolysaccharidoses: A cross-sectional analysis.

BackgroundMucopolysaccharidoses (MPS) is a group of hereditary multisystemic lysosomal disorders. Most neuroimaging studies in MPS have focused on the supratentorial compartment and craniocervical junction abnormalities, and data regarding posterior fossa findings are scarce in the literature. Thus, our purpose is to describe posterior fossa findings on magnetic resonance imaging (MRI) of MPS patients.MethodsWe reviewed routine MRI scans of MPS patients being followed up at our institution (types I, II, III, IV, and VI), focusing on posterior fossa structures.ResultsForty‐seven MPS patients were included. MRI‐visible perivascular spaces were commonly found in the midbrain and adjacent to the dentate nuclei (85% and 55% of patients, respectively). White‐matter lesion was not identified in most cases. Its most frequent localizations were in the pons and cerebellum (34% and 30% of patients, respectively). Enlargement of cerebrospinal fluid (CSF) spaces in the posterior fossa was present in 55% of individuals and was more frequent in neuronopathic patients (73% vs 40%; P = .02). Cerebellar volume was classified as normal, apparent macrocerebellum, atrophic, and hypoplastic in 38%, 38%, 21%, and 3% of patients, respectively. A depression of the posterior fossa floor in the midline sagittal plane was found in 22 patients (47%), which was statistical significantly associated with enlargement of CSF spaces (P = .02) and with apparent macrocerebellum (P = .03).ConclusionThe present study compiled the main posterior fossa findings in MPS patients. Classically described in the supratentorial compartment, MRI‐visible perivascular spaces, white matter lesions, and enlarged perivascular spaces were also found in the posterior fossa. However, atrophy, which commonly affects cerebral hemispheres, was not the most frequent cerebellar morphology found in our study. Moreover, potential findings for future research were described.

Distorted Optic Nerve Portends Neurological Complications in Infants With External Hydrocephalus

Background: Benign external hydrocephalus (BEH) is defined by rapid increase in head circumference in infancy, with neuroimaging evidence of enlarged cerebrospinal fluid (CSF) spaces. BEH was postulated to predispose to subdural hematoma, neurocognitive impairments, and autism. There is currently no consensus on BEH diagnostic criteria and no biomarkers to predict neurological sequalae.Methods: MRI-based quantitative approach was used for measurement of potential imaging markers related to external hydrocephalus and their association with neurological outcomes. We scanned 23 infants diagnosed with BEH and 11 age-similar controls. Using anatomical measurements from a large sample of healthy infants (n = 150), Z-scores were calculated to classify subject's CSF spaces as enlarged (≥1.96SD of mean values) or normal.Results: Subjects with abnormally enlarged CSF spaces had a significantly wider and longer ON (p = 0.017 and p = 0.020, respectively), and a significantly less tortuous ON (p = 0.006). ON deformity demonstrated a high diagnostic accuracy for abnormally enlarged frontal subarachnoid space (AUC = 0.826) and interhemispheric fissure (AUC = 0.833). No significant association found between enlarged CSF spaces and neurological complications (OR = 0.330, 95%CI 0.070–1.553, p = 0.161). However, cluster analysis identified a distinct subgroup of children (23/34, 67.6%) with enlarged CSF spaces and a wider, longer and less tortuous ON, to have an increased risk for neurological complications (RR = 7.28, 95%CI 1.07–49.40).Discussion: This is the first report on the association between external hydrocephalus, ON deformity and neurological complications. Our findings challenge the current view of external hydrocephalus as a benign condition. ON deformity is a potential auxiliary marker for risk stratification in patients with enlarged CSF spaces.

Neural correlates of visual memory in patients with diffuse axonal injury

ABSTRACTPrimary objective: To investigate the neural substrates of visual memory in a sample of patients with traumatic brain injury (TBI). We hypothesized that patients with decreased grey and white matter volume in frontal and parietal cortices as well as medial temporal and occipital lobes would perform poorly on the tests of visual memory analysed.Methods and procedures: 39 patients and 53 controls were assessed on tests of visual memory and learning from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Patients with TBI were scanned with magnetic resonance imaging (MRI). Partial correlations and multiple regression analyses were used to examine relationships between cognitive variables and MRI volumetric findings. This study complements and extends previous studies by performing volumetric comparisons on a variety of resolution levels, from whole brain to voxel-based level analysis.Main outcomes and results: Patients with TBI performed significantly worse than controls in all the tasks assessed. Performance was associated with wide-spread reductions in grey and white matter volume of several cortical and subcortical structures as well as with cerebrospinal fluid space enlargement in accordance with previous studies of memory in patients with TBI and cognitive models suggesting that memory problems involve the alteration of multiple systems.Conclusions: Our results propose that compromised visual memory in patients with TBI is related to a distributed pattern of volume loss in regions mediating memory and attentional processing.

Subdural hematoma in infants: can it occur spontaneously? Data from a prospective series and critical review of the literature by Vinchon et al

Dear Editor, Now that Vinchon [1] has validated Piatt's [2] observation that the diagnosis of abuse is unsafe in infants with preexisting enlarged cerebrospinal fluid spaces, the entire abuse literature needs revision to remove all such cases from the abuse category to the non-abuse or at least the undetermined categories. Rather than comparing “spontaneous” to “abuse” cases, Vinchon apparently has sufficient clinical material to compare those cases with either rapid head growth (crossing two percentile lines) or increased space between the brain and skull (McNeely [3] used 5 mm) on presentation to those without. This may be the more informative comparison. References

Variations in the shape of the frontobasal brain region in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) emerges during childhood through young adulthood coinciding with the late phases of postnatal brain development when fine remodeling of brain anatomy takes place. Previous research has suggested the existence of subtle anatomical alterations in OCD involving focal volume variations in different brain regions including the frontal lobes and basal ganglia. We investigated whether anatomical changes might also involve variations in the shape of the frontobasal region. A total of 101 OCD patients and 101 control subjects were examined using magnetic resonance imaging. A cross-sectional image highly representative of frontal-basal ganglia anatomy was selected in each individual and 25 reliable anatomical landmarks were identified to assess shape changes. A pixel-wise morphing approach was also used to dynamically illustrate the findings. We found significant group differences for overall landmark position and for most individual landmarks delimiting the defined frontobasal region. OCD patients showed a deformation pattern involving shortening of the anterior-posterior dimension of the frontal lobes and basal ganglia, and enlargement of cerebrospinal fluid spaces around the frontal opercula. In addition, we observed significant correlation of brain tissue shape variation with frontal sinus size. Identification of a global change in the shape of the frontobasal region may further contribute to characterizing the nature of brain alterations in OCD. The coincidence of brain shape variations with morphological changes in the frontal sinus indicates a potential association of OCD to late development disturbances, as the frontal sinus macroscopically emerges during the transition between childhood and adulthood.

Evaluation of the Optic Nerve Complex in the Orbit Using Coronal Fast Magnetic Resonance Imaging

Recently available coronal fast magnetic resonance imaging (MRI) has very high spatial resolution with good contrast between the optic nerves and cerebrospinal fluid (CSF). The aim of this study was to evaluate the diagnostic value of coronal fast imaging in optic nerve diseases. Thirty-five patients with various Neuro-ophthalmic conditions including 9 with optic neuritis, 6 with optic atrophy, 5 with glaucoma, 4 with segmental optic nerve hypoplasia and 11 with other optic neuropathies including orbital apex syndrome were evaluated with the three-dimensional fast imaging employing steady-state acquisition (FIESTA) sequence in addition to standard MRI protocols. The optic nerve complexes were evaluated on coronal images of the orbits. Detailed demonstration of the optic nerve complex—the optic nerve, the perineural CSF space and dural sheath—could be readily obtained with FIESTA sequence. The acute phase of both optic neuritis and perineuritis showed enlargement of the perineural CSF space; the optic nerve was swollen in optic neuritis but not in perineuritis. Cases of optic atrophy and glaucoma showed perineural CSF space enlargement with normal optic sheath circumference and a thinner optic nerve, while optic nerve hypoplasia showed a smaller dural sheath circumference without perineural CSF space enlargement. In the cases of orbital apex syndrome optic nerve compression by the extraocular muscles was clearly shown. Coronal FIESTA imaging of the orbit is capable of delineating detailed structural changes in the optic nerve complex and is of diagnostic value for the differentiation of optic nerve diseases.

Reply to the comments of Dr. Abadal and colleagues on “Transcranial color-coded sonography in head injury”

Sirs, We appreciate the interest of Dr. Abadal and colleagues in our work [1]. Their comments confirm that beyond its well-established use in detection of intracranial artery narrowing and spasm, transcranial colorcoded duplex sonography (TCCS) is increasingly used to monitor headinjured patients [1–3]. The experience of Dr. Abadal and colleagues is not limited to the sonographic evaluation of cerebral hemodynamics. They also use TCCS to measure the shift of midline structures in neurosurgical patients. In their quest for reducing the number of follow-up computed tomography (CT) examinations [3], they have found very strong agreement between CT and sonographic measurements of the shift [3]. Nevertheless, we think it is very important to appreciate some shortcomings of sonographic measurements of midline shift. Midline shift is an effect of a unilateral increase in intracranial pressure which in traumatic head injury can be caused by a spaceoccupying lesion, local brain edema or ischemic brain injury. The degree of midline shift also depends on actual volume of intracranial cerebrospinal fluid (CSF) reserve. In patients with preexisting brain volume loss and enlarged CSF spaces, this shift will be minimal or zero even with a relatively large hemispheric lesion. As shown in Fig. 1A, the hemispheric local edema in an 80-year-old patient had no effect on midline shift. However, this would influence the hemodynamics in the affected hemisphere, and this in turn can be evaluated with TCCS. In order to avoid ischemic insult, it is more important to detect quickly and accurately any critical cerebral blood flow disturbances rather than midline shift, as the latter is a poorer indicator of the imminent ischemic insult in head-injured patients. In our study, high rather than low resistance indices as well as low velocities indicated poor outcome. When comparing CT and sonographic measurements of the midline shift, one should be aware that the axial CT plane is not the same as the sonographic plane [4]. Figure 1A shows the ultrasound beam reaching the third ventricle at a 30–35° angle in relation to the horizontal plane. Thus, the distance between the third ventricle and the face of the probe is substantially greater than the distance measured in the axial CT plane. Moreover, even a small change in angulation of the probe is likely to result in a quite substantial change in the measured distance between the third ventricle and the probe. The exact positioning of the probe is usually poorly controlled for by a sonographer. In the patient whose J. Kochanowicz . Z. Mariak Department of Neurosurgery, Medical University of Bialystok, Bialystok, Poland

Positional skull deformities in children: skull deformation without synostosis

Patients with craniosynostosis are readily diagnosed by clinical and neuroimaging findings. Surgical treatment is indicated for preventing neurological deficits and for correcting esthetically unacceptable head deformities. In recent years, we have witnessed a progressive number of neurosurgical consultations for abnormal head shapes unrelated to premature fusion of the cranial sutures, especially of positional plagiocephaly. There have been descriptions of abnormalities in the cerebrospinal fluid (CSF) spaces in children with craniosynostosis. The aim of the present study was to investigate the role of the changes of the CSF spaces in the development of positional skull deformities in children. The authors reviewed demographic, clinical, and neuroimaging data of 23 patients assessed for some form of nonsynostotic skull deformity (group A). The results were compared with those of a simultaneous group of nine infants diagnosed with benign extracerebral collections of fluid (group B). The study group was composed of 11 boys and 12 girls, aged 3 years or younger. Seventeen children had plagiocephaly, four scaphocephaly, and two brachycephaly. Sixteen children (15 with plagiocephaly and 1 with brachycephaly) exhibited enlarged subarachnoid CSF spaces. In group B, the boy/girl ratio was of 7:2. Infants in group A presented at an older age (mean 12.7 months) than group B (mean age at presentation of 7.17 months). Children with benign extracerebral fluid collections were born with a head circumference (HC) greater than infants with positional skull deformities (p=0.005). The percentile of the children's HC at consultation was also larger for children of group B (p=0.03). The form of clinical presentation differed between the two groups. Most infants of group A were seen because of a type of head deformity, and children in group B were studied for macrocephaly. Long-term follow-up assessment showed better outcomes for patients in group B than for children of group A in regard to regression of initial symptoms (p=0.03). Most positional head deformities appear to be related with the children's positioning for sleeping. We have not confirmed macrocephaly as a contributing factor for positional deformities. The distribution of extracerebral CSF and the presence of abnormal collections of fluid in children with positional head deformities do not seem to be related with the findings of pericerebral CSF encountered in children with benign extracerebral collections of fluid. In our view, brain pulsations, transmitted to these accumulations of CSF, play an important part in the development of the infants' skull deformities (p=0.02). The findings of enlarged CSF spaces in children with nonsynostotic skull deformation constituted an age-related event, as these collections tended to disappear as the children grew older (p=0.04).

The Timing of Neurodevelopmental Abnormality in Schizophrenia: An Integrative Review of the Neuroimaging Literature

In this paper we will review recent neuroimaging research in schizophrenia, with an aim to critically evaluate several recent proposals concerning the nature and the timing of the neuroanatomic abnormalities underlying the disorder. Specifically, enlargement of cerebrospinal fluid spaces, deficits in cortical gray matter, and reduced volume of mesiotemporal structures have all been reported in patients in the first episode of schizophrenia, their first-degree relatives, and individuals with schizotypal personality disorder, supporting the possibility that these abnormalities reflect a genetically mediated neurodevelopmental disorder. These findings from the empirical literature will be synthesized from the perspective of dual cytoarchitectonic trends theory of neurodevelopment, as well as in relation to current conceptions of the schizophrenia prodrome. We believe that the evidence shows that sufficient groundwork has been laid to begin longitudinal neuroimaging studies of adolescents at clinical risk for schizophrenia, in order to more definitively determine the pathophysiology of the disorder. Such information could have significant implications in terms of understanding the prediction, treatment, and ultimately the prevention of schizophrenia.

Cerebral CT findings in male opioid-dependent patients: Stereological, planimetric and linear measurements

Cerebrospinal fluid (CSF) space enlargement has been demonstrated in substance-related disorders like alcohol and cocaine dependence. Experimental animal studies showed a reduction in shape and size of mesolimbic dopaminergic neurons after chronic morphine administration. Other studies indicated a change of neurofilament and glial fibrillary acid proteins after chronic opiate administration. Furthermore, frequent overdosing and toxicological effects of `street'-heroin may lead to CSF space enlargement in opioid dependence. In our study the pericortical and ventricular CSF space of 21 male opioid-dependent patients was compared with an age- and sex-matched normal control group. Considering serious problems with ratio and proportion measures, we used a battery of linear (cella media index, Huckman number, frontal horn index), planimetric (cortical atrophy score) and stereological volumetric measures in order to detect differences in cranial computerized tomography scans. We found a significant ventricular and cortical volume loss of the brain in opioid-dependent patients. A higher degree of frontal lobe volume loss seemed to be associated with a shorter period of abstinence before relapse. However, the etiology of volume loss of the brain in opioid-dependent patients is still unclear, but experimental animal studies provide some evidence that long-term, chronic opiate exposure is associated with visible changes of specific structures in the brain.

Structural brain abnormalities in schizophrenia: A family study

Structural brain abnormalities such as ventricular enlargement are robust correlates of schizophrenia, but the degree of difference compared with unrelated normal controls is only moderate (< 1 standard deviation), and only 40% of patients have values on these measures that fall outside of the normal distribution. Family studies can help to clarify the meaning of this overlap by controlling for some of the non-schizophrenia-related genetic variation in neuroanatomical traits. Computerized tomographic scans of the brain were used to measure ventricular and sulcal cerebrospinal fluid (CSF) to brain ratios (VBR and SBR) for each hemisphere in 16 pairs of discordant siblings from the Copenhagen Schizophrenia High-Risk Project. Schizophrenics' values for VBR and SBR exceeded those of their nonschizophrenic siblings in 75% of the pairs; on average, patients' values on these measures were 1 and 5 standard deviations larger, respectively, than those of their nonschizophrenic siblings. Sulcal and left hemisphere effects were significantly more pronounced than ventricular and right hemisphere effects. After controlling for between-family variation, structural brain abnormalities appear to be more prevalent and more pronounced in schizophrenia than has previously been assumed, with relatively greater deviation observed for cortical and left hemisphere measures of CSF space enlargement.

MRI, MRA, and neurodevelopmental outcome following neonatal ECMO

Cranial magnetic resonance imaging (MRI) of 31 newborn infants treated with venoarterial cardiopulmonary bypass for severe but reversible respiratory failure, revealed major focal parenchymal lesions in 7 of 31 infants (23%) and demonstrated abnormal enlargement of extra-axial and ventricular cerebrospinal fluid spaces in 16 of 31 (51%). No preferential left versus right lateralization of focal injury was observed in conjunction with right common carotid artery and jugular vein ligation. No statistically significant relationships were found between major brain lesions on MRI scans and the clinical characteristics of the pre-extracorporeal membrane oxygenation (ECMO), ECMO, and post-ECMO course. Major focal brain lesions were significantly associated with an asymmetric cerebrovascular response to carotid ligation of the right versus left middle cerebral arteries as detected by magnetic resonance angiography ( P < .05). Enlarged cerebrospinal fluid spaces were not significantly related to the presence of parenchymal MRI lesions, but were associated with lower Bayley neurodevelopmental scores for mental (MDI) and psychomotor evaluations (PDI) at 6 and 12 months ( P < .05). It is concluded that asymmetries of cerebral vascular adaptation detected by magnetic resonance angiography after ECMO may be associated with major brain lesions revealed by MRI. Thereafter, the presence of enlarged cerebrospinal fluid spaces on MRI is associated with a poor shortterm developmental outcome.

Subcortical brain anatomy in anorexia and bulimia

Many studies have reported a generalized decrease in brain volume (pseudoatrophy) in patients with anorexia nervosa and bulimia (Enzmann and Lane 1977; Heinz et al 1977; Hoffman et al 1989a and b; Krieg et al 1989b). To some degree this change is reversible, but some enlargement of cerebrospinal fluid (CSF) spaces appears to persist despite normalization of weight and eating habits (Artmann et al 1985; Krieg et al 1986, 1988). Change that persists after successful treatment might be due to residual damage to the brain or persistent abnormal metabolism; however, it might also represent underdeveloped or involuted areas that were originally responsible for the behavioral pathology (Artmann et al 1985). However, previous in vivo anatomic studies have focused only on the gross finding of CSF space enlargement or have used techniques with poor spatial resolution and partial voluming problems (i.e., single photon emission computed tomography (SPECT); Krieg et al 1989a). Limited studies of regional cerebral metabolism have shown focal changes: one small positron

Cranial computed tomographic findings in children with newly diagnosed acute lymphoblastic leukemia: a prospective follow-up study during treatment.

Cranial computed tomography (CT) was performed on 40 consecutive children with newly diagnosed acute lymphoblastic leukemia (ALL) on admission before any chemotherapy, 5 months after CNS therapy (n = 39) and after 2 to 3 years of therapy (n = 31). Changes related to leukemia were found in only 10% of the patients at the time of diagnosis (4/40). These initial changes, two intracranial hemorrhages, one dural thickening and one contrast enhancement, all disappeared during therapy. The findings which persisted unchanged in the next two CT scans were thought to be normal variations or caused by earlier disorders. CNS therapy consisted of intrathecally and intravenously administered methotrexate in 20 standard risk (SR) patients and cranial irradiation in addition to chemotherapy in 19 intermediate risk (IR) or high risk (HR) patients. Four SR patients developed changes during therapy. Three had enlarged cerebrospinal fluid (CSF) spaces and one developed a focal low density area suggesting disturbances in brain blood circulation and also experienced disturbances in level of consciousness. Of the 19 IR or HR patients, eight developed changes related to the therapy, including four with white matter hypodensity areas, of whom three also had enlarged CSF spaces, and four others who developed enlarged CSF spaces. The medians of the widths of the cortical sulci (P less than .001), insular cisterns (P less than .01), third ventricles (P less than .01), and frontal horns (P less than .05), and also of Evans' ratios (P less than .05) increased significantly after CNS therapy as compared with the findings at diagnosis in the patients who had received cranial irradiation. Most of these changes persisted during the follow-up. We conclude that the clinical value of CT scanning during therapy for ALL is restricted to patients with neurological symptoms or those who have undergone CNS irradiation.

The effect of neuroendocrine secretion on brain morphology and EEG sleep in patients with eating disorders.

Neuroendocrine disturbances [low plasma levels of triiodothyronine (T3), high plasma concentrations of cortisol], morphological brain alterations [enlarged external cerebrospinal fluid (CSF) spaces, dilatation of the ventricles] and altered sleep patterns [fragmented sleep continuity, a reduction of slow wave sleep (SWS) or REM sleep] have been described in patients with anorexia nervosa and bulimia nervosa. The present study investigates to what degree these disturbances interact with each other. In ten anorexic and five bulimic patients cranial computed tomography (CT) to estimate the size of the CSF spaces, blood sampling to measure cortisol and T3 plasma concentrations, and all-night polysomnography were performed. In comparison with patients with normal CT scans, the patients displaying enlarged CSF spaces spent more time in SWS, and the duration of REM sleep was reduced. In the whole sample, a negative correlation was found between the amount of REM sleep and cortisol, whereas a positive association was found between the amount of REM sleep and the T3 level. In addition, the degree of brain shrinkage correlated positively with cortisol and negatively with T3. On the basis of these results, it can be assumed that in patients with eating disorders the disease process with its neuroendocrine alterations affects brain morphology as well as EEG sleep.

High‐resolution computed tomography in multiple sclerosis

Eighty-five patients were classified as having definite (n = 34), probable (n = 18), or possible (n = 33) multiple sclerosis using the criteria of Poser. Each patient had an enhanced computed tomographic examination, and most had cerebrospinal fluid and evoked response studies at the same time. Abnormalities including focal decreased brain density, abnormal enhancement, and cerebrospinal fluid space enlargement were found in 62% of patients (85% of those with definite, 39% of those with probable, and 52% of those with possible multiple sclerosis), and abnormal enhancing areas were demonstrated in 29% (44% of those with definite, 17% of those with probable, and 21% of those with possible disease). In the subgroup of patients with definite multiple sclerosis and recent clinical exacerbation (within the prior 8 weeks), abnormal enhancement was present in 89%. There was a strong correlation between clinical exacerbation and abnormal contrast enhancement. Cerebrospinal fluid studies (IgG, white blood cell count, total protein) had no correlation with exacerbation or abnormal enhancement. Maps of low-density and enhancing areas were similar to those previously described in postmortem studies. Computed tomography thus provides an in vivo, objective, and anatomically specific map of the brain parenchyma and the integrity of the blood-brain barrier that is useful in research studies evaluating the treatment of multiple sclerosis. It is also useful in patients in whom the diagnosis of multiple sclerosis is suspected but not certain on the basis of clinical and laboratory evaluation.

Acquired immunodeficiency syndrome: neuroradiologic findings.

Central nervous system complications depicted by CT in ten patients with acquired immunodeficiency syndrome are described. Three patients had multifocal intra-axial enhancing lesions representing atypical brain abscesses (two with toxoplasmosis, one with candidiasis). A fourth patient with multifocal "ring" lesions whose biopsy was interpreted as suggestive of toxoplasmosis responded poorly to treatment. Following his death three months later of Pneumocystis carinii pneumonia, autopsy revealed primary intracerebral immunoblastic lymphoma. One patient had Kaposi sarcoma involving the right frontal lobe (seen as an enhancing mass on the CT scan). CT findings in the remaining five patients revealed mild to moderate enlargement of cerebrospinal fluid spaces (including ventricles and basal cisternae) as a result of cryptococcal meningitis in three patients and "aseptic" meningitis in two. The two patients in whom early biopsy confirmed toxoplasmosis responded well to anti-infective therapy, resulting in dramatic clinical recoveries.