Whole-brain dynamic CT angiography and perfusion imaging.

The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

Congenital ocular motor apraxia. A possible disconnection syndrome.

In 1952, Cogan introduced the term "congenital ocular motor apraxia" (COA) to describe an abnormality of eye movements characterized by absent or defective voluntary horizontal gaze. Since his original description, there have been few subsequent reports of this disorder. A ten-year review of clinical records from the University of Wisconsin Hospitals disclosed eight patients with COA. In two patients subjected to neuroradiologic testing, agenesis of the corpus callosum was detected. Voluntary horizontal gaze appears to be a learned phenomenon, and defective interhemispheric transfer of visual information may be important in the pathogenesis of COA.

Neoplastic angioendotheliomatosis.

A 60-year-old white man presented with aphasia, seizures, paraparesis, and incontinence. His serologic and hematologic profiles were unremarkable. His cerebrospinal fluid showed pleocytosis, increased daily central nervous system IgG synthesis, increased myelin basic protein, and negative cytology and cultures. Cerebral computed tomography exhibited multiple areas of hypodensity but spinal computed tomography and myelography showed no abnormalities. Cranial and spinal magnetic resonance imaging revealed areas of increased signal on T2-weighted images. The use of gadolinium-pentetic acid on T1-weighted images delineated smaller areas of cortical enhancement with surrounding rim of decreased signal. Brain biopsy showed intravascular malignant cells positive for leukocyte common antigen and B-cell markers. The diagnosis was neoplastic angioendotheliomatosis (intravascular lymphomatosis). To our knowledge, this is the first report on the use of both cranial and spinal magnetic resonance imaging in this condition.

Neurologic involvement in toxemia of pregnancy: reversible MRI lesions.

Three women presenting with toxemia of pregnancy revealed reversible increased signal intensity on T2-weighted images by MRI. Overall, neuroradiologic techniques, with MRI the most sensitive, help elucidate the pathophysiology and facilitate the diagnosis in this condition.

Central pontine myelinolysis. Considerations on etiology, diagnosis, and treatment.

Pontine myelinolysis can be suspected clinically on the basis of the following criteria: (1) Electrolyte disturbance manifested mainly by hyponatremia; (2) progressive neurologic deficits resulting in a "locked-in" syndrome; (3) usually, but not necessarily, alcohol abuse; and (4) frequent iatrogenic precipitation of the syndrome by inappropriate rehydration of patients at risk. A major pathophysiologic mechanism for this disorder seems to be the anatomic grid structure of the base of the pons, which is more vulnerable to edema than the cerebral hemispheres. Treatment should be focused on rapid reversal of electrolyte imbalance and judicious use of dehydrating agents. Early diagnosis and treatment might reverse an otherwise malignant syndrome.

Reenactment of the triggering situation for the diagnosis of epilepsy.

When a fixed set of ambient circumstances is associated with convulsive or nonconvulsive paroxysmal attacks, reenactment of the situation should be considered as a possible shortcut for reaching a diagnosis. Reenactment determined the diagnosis in 30 of 32 patients with paroxysmal disorders. The referral diagnosis was correct in only 13 of the 32 patients. To be appropriately executed, the reenactment should entail polygraphic recording of at least EEG, ECG, and respiration. Vertex electrodes should be included to avoid overlooking of cortical electrodecremental event. If unsuccessful at the first attempt, reenactment should be repeated.

Clinical significance of MRI white matter lesions in the elderly.

The clinical relevance of white matter hyperintensities (WMH) seen on MRIs of elderly individuals is controversial. To resolve this issue, we performed MRI and neuropsychological testing on 46 healthy participants in the longitudinal Aging Process Study at the University of New Mexico. We graded the MRIs for severity of WMH using a scale tested on an elderly patient population. We found that 22% of normal subjects had moderate lesions and 9% had severe lesions. All subjects had normal neurologic examination findings and were within normal limits on a battery of neuropsychological tests. Neuropsychological performance decreased and the severity of WMH increased with age. However, when the data were corrected for age, there was no correlation between neuropsychological function and the presence of WMH. We conclude that white matter changes in the elderly by themselves are of doubtful clinical significance.

Familial cavernous angiomas of the brain in an Hispanic family.

We found cavernous angiomas (CA) in 10 of 22 members of a large Hispanic family. The proband had seizures, and a CA was found at surgery. He and two sisters with seizures had normal angiograms, but CT or MRI showed lesions compatible with CA. Similar abnormalities were found in two cousins with seizures and 5 of 17 asymptomatic relatives studied. MRI proved to be more sensitive than CT for identifying CA. Hispanic families appear to have a predisposition for dominantly inherited CA of the brain.

Magnetoencephalographic patterns of epileptiform activity in children with regressive autism spectrum disorders.

BACKGROUND: One-third of children diagnosed with autism spectrum disorders (ASDs) are reported to have had normal early development followed by an autistic regression between the ages of 2 and 3 years. This clinical profile partly parallels that seen in Landau-Kleffner syndrome (LKS), an acquired language disorder (aphasia) believed to be caused by epileptiform activity. Given the additional observation that one-third of autistic children experience one or more seizures by adolescence, epileptiform activity may play a causal role in some cases of autism. OBJECTIVE: To compare and contrast patterns of epileptiform activity in children with autistic regressions versus classic LKS to determine if there is neurobiological overlap between these conditions. It was hypothesized that many children with regressive ASDs would show epileptiform activity in a multifocal pattern that includes the same brain regions implicated in LKS. DESIGN: Magnetoencephalography (MEG), a noninvasive method for identifying zones of abnormal brain electrophysiology, was used to evaluate patterns of epileptiform activity during stage III sleep in 6 children with classic LKS and 50 children with regressive ASDs with onset between 20 and 36 months of age (16 with autism and 34 with pervasive developmental disorder-not otherwise specified). Whereas 5 of the 6 children with LKS had been previously diagnosed with complex-partial seizures, a clinical seizure disorder had been diagnosed for only 15 of the 50 ASD children. However, all the children in this study had been reported to occasionally demonstrate unusual behaviors (eg, rapid blinking, holding of the hands to the ears, unprovoked crying episodes, and/or brief staring spells) which, if exhibited by a normal child, might be interpreted as indicative of a subclinical epileptiform condition. MEG data were compared with simultaneously recorded electroencephalography (EEG) data, and with data from previous 1-hour and/or 24-hour clinical EEG, when available. Multiple-dipole, spatiotemporal modeling was used to identify sites of origin and propagation for epileptiform transients. RESULTS: The MEG of all children with LKS showed primary or secondary epileptiform involvement of the left intra/perisylvian region, with all but 1 child showing additional involvement of the right sylvian region. In all cases of LKS, independent epileptiform activity beyond the sylvian region was absent, although propagation of activity to frontal or parietal regions was seen occasionally. MEG identified epileptiform activity in 41 of the 50 (82%) children with ASDs. In contrast, simultaneous EEG revealed epileptiform activity in only 68%. When epileptiform activity was present in the ASDs, the same intra/perisylvian regions seen to be epileptiform in LKS were active in 85% of the cases. Whereas primary activity outside of the sylvian regions was not seen for any of the children with LKS, 75% of the ASD children with epileptiform activity demonstrated additional nonsylvian zones of independent epileptiform activity. Despite the multifocal nature of the epileptiform activity in the ASDs, neurosurgical intervention aimed at control has lead to a reduction of autistic features and improvement in language skills in 12 of 18 cases. CONCLUSIONS: This study demonstrates that there is a subset of children with ASDs who demonstrate clinically relevant epileptiform activity during slow-wave sleep, and that this activity may be present even in the absence of a clinical seizure disorder. MEG showed significantly greater sensitivity to this epileptiform activity than simultaneous EEG, 1-hour clinical EEG, and 24-hour clinical EEG. The multifocal epileptiform pattern identified by MEG in the ASDs typically includes the same perisylvian brain regions identified as abnormal in LKS. When epileptiform activity is present in the ASDs, therapeutic strategies (antiepileptic drugs, steroids, and even neurosurgery) aimed at its control can lead to a significa

Scintigraphic appearance of uncommon soft-tissue osteogenic sarcoma metastases.

The advent of improved chemotherapy has changed the natural course of osteosarcoma. The role of bone scintigraphy in the workup of metastatic osteosarcoma is being re-evaluated. Extra-osseous osteogenic sarcoma metastases, particularly pulmonary metastases, are known to accumulate bone-avid agents. In this case, there is also uptake by noncalcified metastases to the brain and to soft tissues of the leg and arm which has not been previously reported. Correlation with computed tomography and magnetic resonance imaging is made.

The Dubowitz syndrome: further observations.

An autosomal recessive disorder characterized by intrauterine growth retardation, postnatal retardation, microcephaly, sparse hair, toe syndactyly, and characteristic facial appearance is now recognized as the Dubowitz syndrome. Five addition additional cases of the Dubowitz syndrome are reported, including 2 with documented vascular abnormalities.

Magnetic resonance imaging of severely disturbed children--a preliminary study.

This study investigates the relationship between brain pathology and psychiatric disturbance in 37 psychiatric inpatients between 5 and 14 years of age referred for magnetic resonance imaging (MRI). Of 37 images, 13 were categorized as abnormal by neuroradiologists who were blind to the diagnoses of subjects. Three of six children with schizophrenia-related diagnoses had abnormal scans. In contrast, only one of 15 children with a primary disruptive behavior disorder diagnosis had an abnormal magnetic resonance image. A greater proportion of children with schizophrenia spectrum diagnoses had greater left than right frontal horns of the lateral ventricles than children with other diagnoses.

Direct thrombolysis of superior sagittal sinus thrombosis with coexisting intracranial hemorrhage.

We present a case of dural cerebral venous thrombosis with coexisting left frontal hemorrhage that was successfully treated with 13.79 million units of urokinase over a period of 165 hours.

Neonatal hypoglycemia: CT and MR findings.

A case of neonatal hypoglycemia with extensive occipital cortical loss is presented. Imaging studies revealed a predominance of brain parenchymal loss in the occipital lobes bilaterally with nearly complete absence of cortex in the posterior parietal and occipital regions and generalized thinning of the cortex throughout the brain.

MR of extraocular muscles in chronic progressive external ophthalmoplegia.

PURPOSE: Our goal was to determine whether the extraocular muscles in patients with chronic progressive external ophthalmoplegia (CPEO) could be distinguished from those of age-matched control subjects by MR imaging. METHODS: Nine patients with CPEO and eight age-matched healthy control subjects were studied. The extraocular muscles of eight of the patients (16 eyes) and all the control subjects (16 eyes) were measured digitally. Images consisted of 1.5-mm contiguous sections acquired using a volume (three-dimensional) gradient-echo acquisition. In all, measurements were performed on 11 interpolated 1.0-mm coronal sections, five on each side of the muscle center. Only the medial, inferior, and lateral rectus muscles were evaluated. The superior rectus was omitted to avoid averaging problems with the superior ophthalmic vein and levator palpebrae muscle. The 11 sections were summed to obtain a volume measurement of the central portion of each muscle. RESULTS: The digitally measured extraocular muscles in the patients with CPEO had statistically significantly smaller volumes than those of the control subjects. The average muscle volumes for the patients with CPEO were 215 mm3 for the medial rectus, 202 mm3 for the inferior rectus, and 269 mm3 for the lateral rectus. The average extraocular muscle volumes for the control subjects were 366 mm3 for the medial rectus, 365 mm3 for the inferior rectus, and 425 mm3 for the lateral rectus. CONCLUSION: MR imaging can show small extraocular muscles in patients with CPEO, which may help to distinguish this disorder from other entities. Since denervated extraocular muscles do not readily atrophy, this MR sign would support a myogenic pathologic substrate for CPEO. Variation in the degree of extraocular muscle atrophy may simply reflect the length of time the mitochondrial defect and ophthalmoplegia have been present.

Anatomic localization of cerebral cortical function by magnetoencephalography combined with MR imaging and CT.

Magnetoencephalography (MEG) monitors magnetic field amplitudes, which are time averages of evoked neuronal responses. This method can detect magnetic fields emanating from the brain and localize the neuronal source. The location of somatosensory neuronal sources for voluntary right thumb and right index finger flexions were determined in four normal volunteers by using a seven-sensor neuromagnetometer inside a magnetically shielded room. These neuronal sources were then identified on the individual's respective CT or MR scans, and correlation was accomplished by geometric calculations, direct cranial measurement, and surface marker identification. Specific functional magnetic fields were located over the appropriate sensory motor cortex; however, there was considerable variation in the exact site. Magnetoencephalography combined with CT and MR may improve localization of normal and abnormal neurologic function.

MR imaging of the spinal cord in 23 subjects with ALD-AMN complex.

Twenty-three subjects from two family groups with the adrenoleukodystrophy (ALD)-adrenomyeloneuropathy (AMN) complex were examined with MR imaging at 1.5 T to determine the presence and extent of brain and spinal cord abnormalities. Nineteen individuals were identified as having ALD or AMN, or as having carrier status on the basis of pedigree analysis and/or evaluation of serum very-long-chain fatty acids. In addition to the expected intracranial white matter changes for this disorder, decreased spinal cord diameter was found in seven (30%) of the 23 subjects. In three of these cases, atrophy was limited to the thoracic spinal cord, while atrophy of both the cervical and thoracic cord was identified in four patients. Two patients who did not have MR imaging of the spine were found to have spinal cord atrophy at autopsy. The finding of decreased spinal cord diameter on MR examinations in individuals who are heterozygous for ALD-AMN, in patients with ALD or AMN, and in asymptomatic ALD-AMN patients may represent a new anatomic marker for the variable clinical presentations of this condition. In addition to cranial MR examination, MR imaging of the spine may be indicated in patients with suspected ALD or AMN, or in women with carrier status.

MR 'hot nose sign' and 'intravascular enhancement sign' in brain death.

Three cases of MR with gadopentetate dimeglumine in patients diagnosed with cerebral death are presented. Observation of an MR "hot nose sign" and an "intravascular enhancement sign" provided additional imaging support in the clinical diagnosis of brain death. The MR findings in brain death include: 1) transtentorial and foramen magnum herniation, 2) absent intracranial vascular flow void, 3) poor gray matter/white matter differentiation, 4) no intracranial contrast enhancement, 5) carotid artery enhancement (intravascular enhancement sign), and 6) prominent nasal and scalp enhancement (MR hot nose sign). Additional modalities for confirming brain death are discussed.

Physiologic intracranial calcification with hyperintensity on MR imaging: case report and experimental model.

CT and MR imaging showed basal ganglia calcification that appeared as high signal intensity on T1-weighted images of a patient with pseudohypoparathyroidism. MR imaging of an experimental model of calcium phosphate suspensions showed a signal similar to that seen in the patient. Additionally, T1 and T2 relaxation times of the solutions were measured and showed decreases in both parameters with increasing calcium phosphate concentrations. Intracranial calcification can appear as high signal intensity on T1-weighted images. An experimental model shows that the calcium salt decreases the T1 of surrounding water. Therefore, calcium, and possibly other elements, may induce paramagnetic susceptibility effects.

Neuromagnetic assessment of pathophysiologic brain activity induced by minor head trauma.

BACKGROUND AND PURPOSE: Patients with mild traumatic brain injury (TBI) often show significant neuropsychological dysfunction despite the absence of abnormalities on traditional neuroradiologic examinations or EEG. Our objective was to determine if magnetic source imaging (MSI), using a combination of MR imaging and magnetoencephalography (MEG), is more sensitive than EEG and MR imaging in providing objective evidence of minor brain injury. METHODS: Four subject groups were evaluated with MR, MSI, and EEG. Group A consisted of 20 neurologically normal control subjects without histories of head trauma. Group B consisted of 10 subjects with histories of mild head trauma but complete recovery. Group C consisted of 20 subjects with histories of mild head injury and persistent postconcussive symptoms. The 15 subjects included in group D underwent repeat examinations at an interval of 2 to 4 months. RESULTS: No MR abnormalities were seen in the normal control group or the asymptomatic group, but five (20%) of the patients with persistent postconcussive symptoms had abnormal MR findings. EEG was abnormal for one subject (5%) from the normal control group, one (10%) from the asymptomatic group, and five (20%) from the group with persistent postconcussive symptoms. MSI was abnormal for one subject (5%) from the normal control group, one (10%) from the asymptomatic group, and 13 (65%) from the group with persistent postconcussive symptoms. There was a direct correlation between symptom resolution and MSI findings for the symptomatic head trauma group. CONCLUSION: MSI indicated brain dysfunction in significantly more patients with postconcussive symptoms than either EEG or MR imaging (P < .01). The presence of excessive abnormal low-frequency magnetic activity provides objective evidence of brain injury in patients with postconcussive syndromes and correlates well with the degree of symptomatic recovery.