Overwhelming CNS cryptococcus in AIDS.
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AIDS-Related Opportunistic Infections↗
Biomedical subjects
P A Hofman
Publications and source records attributed to P A Hofman.
Thalamic volume predicts performance on tests of cognitive speed and decreases in healthy aging. A magnetic resonance imaging-based volumetric analysis.
Recent studies have indicated a role for the thalamus in attention, arousal and the capacity to perform tasks of speeded information processing. The present study evaluated the role of the thalamus in age-related cognitive decline by investigating the correlations between thalamic volume, cognition and age. This was done in 57 healthy subjects ranging from 21 to 82 years of age. All subjects underwent neurocognitive testing with information processing tests and structural magnetic resonance imaging. A significant decrease in volume of the thalamus with increasing age was found, relatively stronger than and independent of the decrease of total brain volume. The decrease of thalamic volume was apparent before the onset of loss of volume of the total brain. Over the age-span studied, the thalamic decrease in volume correlated with the diminished performance on tests of cognitive speed. Additionally, in young and middle-aged, but not in old subjects, the size of the thalamus predicted performance on tasks that require cognitive speed.
Adult↗
MR imaging, single-photon emission CT, and neurocognitive performance after mild traumatic brain injury.
BACKGROUND AND PURPOSE: Mild traumatic brain injury (mTBI) (Glasgow Coma Scale = 14-15) is a common neurologic disorder and a common cause of neurocognitive deficits in the young population. Most patients recover fully from mTBI, but 15% to 29% of patients have persistent neurocognitive problems. Although a partially organic origin is considered likely, little brain imaging evidence exists for this assumption. The aims of the present study were to establish the prevalence of posttraumatic lesions in mTBI patients on MR images and to assess the relation between these imaging findings and posttraumatic symptoms. Secondly, we explored the value of early posttraumatic single-photon emission CT (SPECT) for the evaluation of mTBI. METHODS: Twenty-one consecutive patients were included in the study. Patients underwent MR examination, technetium-99m hexamethylpropylene amine oxime SPECT, and neurocognitive assessment within 5 days after injury. Neurocognitive follow-up was conducted 2 and 6 months after injury, and MR imaging was repeated after 6 months. Lesion size and brain atrophy were measured on the MR studies. RESULTS: Twelve (57%) of 21 patients had abnormal MR findings, and 11 (61%) of 18 had abnormal SPECT findings. Patients with abnormal MR or SPECT findings had brain atrophy at follow-up. The mean neurocognitive performance of all subjects was within normal range. There was no difference in neurocognitive performance between patients with normal and abnormal MR findings. Patients with abnormal MR findings only showed significantly slower reaction times during a reaction-time task. Seven patients had persistent neurocognitive complaints and one patient met the criteria for a postconcussional syndrome. CONCLUSION: Brain lesions are common after mTBI; up to 77% of patients may have abnormal findings either on MR images or SPECT scans, and these lesions may lead to brain atrophy. The association between hypoperfusion seen on acute SPECT and brain atrophy after 6 months suggests the possibility of (secondary) ischemic brain damage. There is only a weak correlation between neuroimaging findings and neurocognitive outcome.
Adolescent↗
Value of radiological diagnosis of skull fracture in the management of mild head injury: meta-analysis.
OBJECTIVES: Head injury is a common event. Most patients sustain a mild head injury (MHI), and management depends on the risk of an intracranial haemorrhage (ICH). The value of a plain skull radiograph as a screening tool for ICH is controversial. The aim of this meta-analysis was to estimate and explain differences in reported sensitivity and specificity of the finding of a skull fracture for the diagnosis of ICH, in order to assess the value of the plain skull radiograph in the investigation of patients with MHI, and to estimate the prevalence of ICH in these patients. METHOD: After a systematic literature search 20 studies were selected that reported data on the prevalence of ICH after MHI and/or data on the diagnostic value of skull fracture for the diagnosis of ICH. The mean prevalence of ICH weighted for the sample size was determined. The sensitivity and specificity of different studies were combined using a summary receiver operator characteristic curve. Correlation analysis was used to determine factors that could explain the reported differences between studies. RESULTS: The weighted mean prevalence of ICH after MHI is 0.083. The potential for verification bias and the percentage of patients who had suffered loss of consciousness or post-traumatic amnesia were the most significant factors explaining interstudy differences in sensitivity and specificity. Based on studies wherein at least 50% of patients had a CT study of the brain, the estimated sensitivity of a radiographic finding of skull fracture for the diagnosis of ICH is 0.38 with a corresponding specificity of 0.95. CONCLUSION: The plain skull radiograph is of little value in the initial assessment of MHI patients.
Humans↗
Cognitive dysfunctions and white matter lesions in patients with bipolar disorder in remission.
OBJECTIVE: To compare cognitive functioning in relation to white matter lesions in bipolar disorder in remission and schizophrenia. METHOD: Cognitive performance and the occurrence of white matter lesions on MRI images of the brain were assessed in 22 patients with bipolar disorder in remission, 22 patients with schizophrenia and 22 healthy volunteers. RESULTS: Performance of tests of memory, speed and cognitive flexibility was significantly impaired in both patient groups. The frequency of white matter lesions did not differ significantly between the three groups. No differences in cognitive performance were found between patients with white matter lesions and patients without such lesions. CONCLUSION: White matter lesions apparently do not underlie cognitive deficits that are found in patients with bipolar disorder in remission and in patients with schizophrenia.
Bipolar Disorder↗
Quantitative analysis of magnetization transfer images of the brain: effect of closed head injury, age and sex on white matter.
Magnetization transfer (MT) imaging has an application in quantitative assessment of cerebral white matter. Previously published postprocessing methods have inherent problems, and therefore a new analysis technique is presented. This technique was found to be more sensitive for white matter changes in patients with a postconcussional syndrome, compared to other methods previously described. Because of the potential application of this technique in longitudinal and group studies, age and sex dependence of the MT ratio (MTR) of white matter were studied. In a group of 51 healthy subjects, a decrease in the mean MTR as well as an increasing distribution width of the MTR was found with increasing age. The mean MTR in males was higher than in females. These results stress the need to take age and sex into account when interpreting MTR data. Magn Reson Med 42:803-806, 1999.
Adult↗
Brain correlates of memory dysfunction in alcoholic Korsakoff's syndrome.
OBJECTIVES: To investigate the relation between anterograde amnesia and atrophy of brain structures involved in memory processing in alcoholic Korsakoff's syndrome. METHODS: The volume of brain structures involved in memory processing was measured with MRI from 13 subjects with Korsakoff's syndrome, 13 subjects with chronic alcoholism without Korsakoff's syndrome, and 13 control subjects. The brain structures analysed were the hippocampus, the parahippocampal gyrus, the mamillary bodies, the third ventricle, and the thalamus. Brain volumes were correlated with the delayed recall of a verbal learning test. RESULTS: Compared with subjects with chronic alcoholism and control subjects, subjects with Korsakoff's syndrome had a reduced volume of the hippocampus, the mamillary bodies, and the thalamus, and enlargement of the third ventricle. The impairment of delayed recall correlated with the volume of the third ventricle (r=-0.55, p=0.05) in the Korsakoff group. CONCLUSIONS: Anterograde amnesia in alcoholic Korsakoff's syndrome is associated with atrophy of the nuclei in the midline of the thalamus, but not with atrophy of the mamillary bodies, the hippocampus, or the parahippocampal gyrus.
Alcoholism↗
MRI of the postoperative lumbar spine: triple-dose gadodiamide and fat suppression.
In ten patients who had undergone lumbar laminectomy, visual assessment of epidural scar enhancement and diagnostic confidence was performed after 0.1 mmol/kg gadodiamide intravenously, again after a further 0.2 mmol/kg, and once more using a fat-suppression sequence. The single-dose contrast-enhanced T1-weighted images showed clear enhancement of epidural scar in eight cases, and clearly improved diagnostic confidence as regards scar and/or disc herniation in six. Triple-dose contrast-enhanced images showed further increase in epidural enhancement clearly in only two cases and marginally in six, with no significant increase in diagnostic confidence. Fat-suppression, performed in eight cases, showed a further clear increase in epidural enhancement in seven cases, but again no increase in diagnostic confidence. In one patient with arachnoiditis contrast enhancement and diagnostic confidence increased only slightly after each contrast injection, and again with the fat-suppression sequence. Increasing contrast medium dose was thus not useful following laminectomy when epidural scarring obscures a possible recurrent disc herniation. Use of fat suppression may, however, permit reduction of the dose of contrast medium necessary to provide adequate scar enhancement.
Adult↗
Optimising the image of the intradural nerve root: the value of MR radiculography.
We evaluated the additional value of MR radiculography for increasing the sensitivity and specificity of MRI with regard to nerve root compression in patients with sciatica. The single slices of a heavily T2-weighted oblique coronal image set were reformatted with a maximum intensity projection protocol. This image resembles a classical contrast radiculogram and shows the intradural nerve root and its sleeve. In 43 patients studied with a standard MRI examination there was a need for further assessment of nerve root compression in 19 (44%). In 13 (68%) of these, MR radiculography made a definite verdict possible.
Dura Mater↗
3-D volume scanning. A new technique for lumbar MR imaging.
A 3-D volume magnetic resonance (MR) acquisition utilizing a T1-weighted gradient-echo sequence provides an excellent image of the intradural nerve roots. In a 6 1/2 minute acquisition, 64 overlapping 2 mm slices can be obtained. High-quality reformats into other planes can be performed creating an "MR radiculogram" in considerably less time than necessary at present for a lumbar MRI study. In 30 patients with sciatica, the volume scan was compared to our standard lumbar MR protocol, consisting of sagittal and transverse spin-echo T1-weighted sequences and a long-TR sequence. The image sets were rated on a 5-point scale for disk herniation and nerve root compression at L 3-4, L 4-5, and L 5-S 1 on both sides; thus 180 locations were assessed. The volume scan invariably produced a better nerve root image than the standard examination, but the smaller signal to noise ratio affected especially the image of the vertebral body. Significant disagreement in ratings between the two techniques was seen at 7 locations for disk herniation, and at 6 locations for root compression. Review of the two studies upheld the verdict of the volume scan in 6 cases of herniation and 3 cases of root compression. Clear-cut verdicts (definitely normal or abnormal) were possible in over 90% with both techniques. Lumbar 3-D volume scanning thus appears to be at least equivalent to MR scanning protocols as currently used. Additionally, the nerve root is much better depicted with the volume scan, and examination time is considerably reduced.
Diagnosis, Differential↗
Timing of osteosynthesis of major fractures in patients with severe brain injury.
A retrospective study was performed to assess the effects on outcome of early osteosynthesis of major extremity fractures in patients with severe brain injury (GCS less than or equal to 7). In a consecutive series of 58 patients, early osteosynthesis was performed on the day of injury in 15 patients. (Group A). In 43 patients no major fractures were present or no early osteosynthesis was performed (Group B). The severity of brain injury as seen on CT scan was similar in both groups. Mortality was significantly lower in Group A, despite a significantly higher ISS. As to the functional end result of brain injury, an indication of a better outcome was present in Group A.
Adolescent↗
Neuropsychiatric and neuropsychological manifestations of central pontine myelinolysis.
A patient with central pontine myelinolysis (CPM) underwent neurological and mental status examination, as well as neuropsychological testing, during the acute stage of the disease. After correction of the hyponatremia, a gross change in his neuropsychiatric status was observed. The patient underwent extensive neurological, psychiatric, and neuropsychological testing during the acute phase of the disease and at follow-up 4 months later. All major neurological and neuropsychiatric symptoms present at onset were fully reversible. Neuropsychological examination revealed deficits in the domains of attention and concentration, short-term memory and memory consolidation, visual motor and fine motor speeds, and learning ability. Although improved, neuropsychological testing still revealed remarkable deficits at follow-up. We conclude that neuropsychological deficits can accompany CPM, and that these deficits do not necessarily diminish simultaneously with the radiological or clinical neurological findings but may persist for a longer period of time, or even become permanent. In his recovery the patient started to manifest new neurological symptoms consisting of a mild resting tremor of both hands and slow choreoathetotic movements of the trunk and the head, which we considered to be late neurological sequelae of CPM. The significance of CPM in the differential diagnosis of acute behavioral changes after correction of hyponatremia is stressed, even if correction is achieved slowly and carefully.
Adult↗