Answer to case of the month #60. Postoperative dissemination of fat particles in the subarachnoid spaces and intraventricular system from spinal dermoid tumour.
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Adipocytes↗
Biomedical subjects
D Melançon
Publications and source records attributed to D Melançon.
Late-onset temporal lobe epilepsy and dilatation of the hippocampal sulcus by an enlarged Virchow-Robin space.
MRI signal changes within the hippocampal sulcus have been attributed to a dilated Virchow-Robin space within that sulcus, but no clinical correlates have previously been described. We present a 64-year-old man who developed right temporal seizures. MRI revealed an unusually enlarged Virchow-Robin space within the hippocampus, suggesting space-occupying effect. Such an abnormality should be considered a possible etiology in patients with late-onset temporal lobe epilepsy.
Age of Onset↗
The negative angiogram in subarachnoid haemorrhage.
Our purpose was to review the incidence of negative cerebral panangiography in acute nontraumatic subarachnoid haemorrhage (SAH); to document the amount and distribution of subarachnoid blood on CT and determine its relationship to findings on repeat angiography; and to study the outcome of these patients from the time of presentation to hospital discharge. From 1983 to 1992, 295 patients underwent cerebral angiography for acute SAH at our institution. The CT, angiographic and MRI findings and clinical course of patients with initially negative angiograms were reviewed retrospectively. The overall incidence of negative cerebral panangiography was 31% (92/295). An aneurysm was disclosed on a second angiogram in 4 cases, and on a third angiogram in 1, giving a total false negative rate of 5%. In 55% of cases, only a small amount of SAH was present on CT. The distribution of the subarachnoid blood was nonspecific and resembled the pattern seen in aneurysmal SAH. Ninety-four percent of the patients presented in Hunt-Hess grades I and II. The complications of conservative treatment were few: a rebleed rate of 4%, delayed cerebral ischemia in 4%, cerebral infarcts in 8% and hydrocephalus requiring shunting in 3%. On discharge, 93% of patients had recovered completely and the others were left with moderate disability. There were two deaths related to massive rebleeding. Patients with perimesencephalic SAH (35%) fared particularly well; none developed complications during their hospital stay and repeat angiograms never revealed an underlying aneurysm. In such cases, further angiographic investigations do not seem warranted.
Angiography, Digital Subtraction↗
Gliomatosis cerebri.
PURPOSE: To characterize gliomatosis cerebri on computed tomographic (CT) and magnetic resonance (MR) images. MATERIALS AND METHODS: MR and CT studies of 22 patients with cerebral gliomatosis were reviewed retrospectively. Tumor was confirmed with autopsy (n=5) or biopsy. Distribution and extent of disease were assessed, and disease progression was followed. RESULTS: Tumor involved at least two lobes of the brain in all patients, with extension to the corpus callosum in 12, basal ganglia and thalamus in 17, brain stem in three, and cerebellum in two patients. Widespread invasion with hyperintensity was noted on proton-density- and T2-weighted MR images. At CT, areas of hypo- or isoattenuation were noted, and no contrast enhancement occurred. Extent of tumor was greater on MR images than on concurrent CT scans in all patients. The MR findings closely correlated with the autopsy findings. CONCLUSION: Gliomatosis cerebri is best detected with MR imaging. The pattern is infiltrative with enlargement of cerebral structures.
Adolescent↗
The role of computed tomographic angiography in the assessment of intracranial vascular disease.
Both technical and clinical implications of three-dimensional computed tomographic angiography in the evaluation of intracranial circulation, and in particular cerebral aneurysms, are presented. Three-dimensional computed tomographic angiography allows excellent visualization of the aneurysm, its neck, and its relationship with the parent artery and important adjacent bony structures. This technique has a major role in the evaluation of difficult aneurysms. In addition, advantages and disadvantages are discussed in comparison with more conventional techniques such as magnetic resonance imaging, magnetic resonance angiography, and digital subtraction angiography. Three-dimensional computed tomographic angiography will continue to develop with the advent of more rapid computed tomography scanners, playing a key role in the investigation and screening of patients with a family history of cerebral aneurysms.
Brain↗
Three-dimensional computed tomographic angiography of cerebral aneurysms.
We describe our technique and results of dynamic, reconstructed, three-dimensional (3-D) computed tomographic (CT) angiography in our first 18 patients with either complex aneurysms, producing subarachnoid hemorrhage or the compression of neighboring structures, or small asymptomatic aneurysms, and assess the role of this technique in treatment planning. A dynamic, infused CT scan producing 1.5-mm cuts of the area of interest was performed, and the two-dimensional images were reconstructed in three dimensions with the ISG Allegro system (ISG Technologies, Toronto, Ontario, Canada). Results were compared with intra-arterial digital subtraction angiography and magnetic resonance angiography. All aneurysms over 3 mm and half of the aneurysms less than or equal to 3 mm were demonstrated by 3-D CT angiography. The neck of the aneurysm, its relationship to the parent artery and associated branches, and its relationship to surrounding bony structures, such as the anterior clinoid, were also demonstrated. This was especially useful for ophthalmic aneurysms. The 3-D image could be rotated on the screen to mimic the operative approach. The active, filling portion and the thrombosed part of partially thrombosed, giant aneurysms could be seen on the same image, and the active, filling portion could be better appreciated with 3-D CT angiography than with magnetic resonance angiography. A partially treated, acrylic-coated aneurysm that could not be completely assessed otherwise has been demonstrated by this technique. 3-D CT angiography is useful in the evaluation of aneurysms, especially when the local anatomy is obscured or distorted by its mass or by the anterior clinoid.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Intramedullary schwannoma.
OBJECTIVE: To present the imaging findings for two cases of intramedullary schwannoma involving the thoracic cord and the conus medullaris. PATIENTS AND METHODS: a 34-year-old man and a 53-year-old woman presented with symptoms of weakness and pain in the lower limbs. Myelography and magnetic resonance imaging as well as other examinations, were performed. RESULTS: The imaging failed to indicate the correct diagnosis in either patient. However, intramedullary schwannoma was confirmed pathologically in both patients. Subtotal excision resulted in local tumour recurrence at 5 and 3 years, respectively. CONCLUSIONS: Intramedullary schwannoma should be considered in the differential diagnosis of spinal cord tumours. The importance of accurate diagnosis from frozen sections at surgical biopsy is emphasized .
Adult↗
Clarification on the anatomy and pathophysiology of posterior fossa cysts.
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Brain Diseases↗
Transcranial Doppler ultrasonographic changes after embolization of cerebral arteriovenous malformations.
The authors assessed the potential role of transcranial Doppler ultrasonography (US) in monitoring hemodynamic changes induced by embolization of cerebral arteriovenous malformations. Transcranial Doppler US was performed in eight patients with such lesions before and after embolization with n-butyl cyanoacrylate [corrected]. Changes in mean flow velocity and pulsatility index were analysed in all feeding and nonfeeding arteries. Anatomic and hemodynamic observations were also correlated with the results of digital subtraction angiography. A consistent trend was observed in all treated feeding arteries after embolization: the flow velocity decreased by a mean of 26% or 33 cm/s (p = 0.01, paired t-test), and the pulsatility index increased by a mean of 27% or 0.15 (p = 0.005). Although these changes did not correlate with the degree of angiographic reduction of the nidus (r = -0.31), they were most marked in malformations with a lower Spetzler grade or a higher degree of shunt obliteration. After embolization, recruitment of untreated feeding arteries was documented in two cases and a decrease in the "steal effect" from contralateral nonfeeding arteries in three. Changes in the nonfeeding arteries ipsilateral and contralateral to the malformation were variable. The authors conclude that transcranial Doppler US is a convenient and reliable method to evaluate quantitatively the hemodynamic effects of embolization of cerebral arteriovenous malformations.
Adult↗
Extension of a cerebellar cystic astrocytoma into the cervical canal, demonstrated by magnetic resonance imaging.
One characteristic feature of ependymomas of the fourth ventricle is a tendency to extend through the foramina, specifically the foramina of Luschka and Magendie, the foramen magnum and the aqueduct of Sylvius. The authors report a case of pilocytic astrocytoma of the cerebellum that mimicked such extension into the upper cervical canal. This finding was revealed by magnetic resonance imaging and confirmed at surgery.
Astrocytoma↗
Multiple occult vascular malformations of the brain and spinal cord: MRI diagnosis.
We report a patient with multiple angiographically occult vascular malformations in the brain and spine. Magnetic resonance imaging showed multiple lesions in brain and spine with hypointense areas on both T1 and T2-weighted images. These hypointense areas are usually secondary to hemosiderin deposits consistent with remote bleeding in the lesions. We conclude that when magnetic resonance reveals an intraspinal lesion with signal intensity characteristics consistent with a vascular malformation, an examination of the brain should be performed to rule out associated intracranial lesions. The finding of multiple lesions in the brain with identical signal intensity characteristics reinforces the diagnosis of vascular malformation.
Brain↗
CT and MR imaging findings in adults with cerebellar medulloblastoma: comparison with findings in children.
The goal of this study was to determine if certain imaging features suggest the diagnosis of cerebellar medulloblastoma in adults and to determine how often the classic CT appearance seen in children is present in adults. The study included 28 adult patients with proved cerebellar medulloblastoma. The tumor was located in the cerebellar vermis in 14 patients and in a cerebellar hemisphere in 14 patients. Thirteen patients had unenhanced CT of the brain, all patients had contrast-enhanced CT, and eight patients had unenhanced MR imaging. The imaging features in adults were compared with those in children, as described in the literature. In our adult patients, all tumors were hyperdense compared with gray matter on unenhanced CT and showed a slight to moderate increase in density after injection of contrast medium. Thirteen lesions had well-defined margins, and 15 had poorly defined margins. Low-density areas consistent with cystic and necrotic degeneration were detected in 23 (82%) of the 28 tumors. By comparison, in children, medulloblastoma usually originates in the vermis. As in adults, the mass is hyperdense on unenhanced CT, but enhances markedly and homogeneously after injection of contrast medium. Usually no evidence of cyst formation or necrosis is seen, and the tumor margins are well defined. This classic CT appearance of medulloblastoma in children was identified in only three (11%) of the 28 adult patients. Medulloblastoma has a variable MR appearance in both children and adults. On T2-weighted images, lesions are hypo-, iso-, or hyperintense compared with normal gray matter. The CT findings of medulloblastoma in adults usually differ from those of medulloblastoma in children. The tumor has a variable and nonspecific appearance in adults and should always be considered in the differential diagnosis of a mass in the posterior fossa.
Adolescent↗
[A simplified terminology for abnormalities of the lumbar disks].
The terminology for abnormalities of the lumbar disk has always been a source of confusion. Recent advances in pathological studies have inspired the authors to propose a simple classification of common disk anomalies suitable not only for diagnostic radiologists but also for referring clinicians. Although the diagnosis of a few pathological entities will only be possible with specific imaging techniques, the proposed classification is appropriate for reporting observations from plain films, conventional tomograms, myelograms, discograms, computed tomography scans and magnetic resonance images. All lumbar disks can thus be classified into one or more of the following categories: normal, aging, scarred, ruptured and herniated. A disk herniation is defined as a localized exit of disk material beyond the limits of the original intervertebral space.
Adult↗
Hydrocephalus and prominence of the choroid plexus: an unusual computed tomographic presentation of cerebral toxoplasmosis in AIDS.
Toxoplasmosis is a frequent cause of infection of the central nervous system (CNS) in patients with acquired immunodeficiency syndrome. Computed tomography (CT) usually shows solitary or multiple parenchymal lesions, which are most often located in the cortex, the juxtacortical white matter and the basal ganglia. The authors describe a 30-year-old immunocompromised Haitian woman with pathologically proven CNS toxoplasmosis who presented with hydrocephalus and prominence of the choroid plexus; there was no evidence of focal parenchymal lesions in contrast-enhanced CT scans. An autopsy revealed diffuse destruction of the ependyma of the lateral, the third and the fourth ventricles. Necrosis was evident, and the periventricular tissues and the choroid plexus were infiltrated with neutrophils and macrophages. Pseudocysts of Toxoplasma were identified near the ventricular surface.
Acquired Immunodeficiency Syndrome↗
Electroencephalography, magnetic resonance imaging and pathology in patients treated surgically for temporal lobe epilepsy.
In a consecutive series of 40 patients selected by EEG studies for surgical treatment of temporal lobe seizures, magnetic resonance imaging showed structural lesions in 25% and signal abnormalities, usually in the mesial temporal region, in another 35%. Pathological changes included structural lesions in over 30% of patients and sclerosis of the amygdala in almost half of the series. These findings further substantiate the implication of the amygdala in the pathogenesis of temporal lobe seizures with automatism and amnesia.
Amygdala↗
A simplified terminology for abnormalities of the lumbar disk.
The terminology for abnormalities of the lumbar disk has always been a source of confusion. Recent advances in pathological studies have inspired the authors to propose a simple classification of common disk anomalies suitable not only for diagnostic radiologists but also for referring clinicians. Although the diagnosis of a few pathological entities will only be possible with specific imaging techniques, the proposed classification is appropriate for reporting observations from plain films, conventional tomograms, myelograms, diskograms, computed tomography scans and magnetic resonance images. All lumbar disks can thus be classified into one or more of the following categories: normal, aging, scarred, ruptured and herniated. A disk herniation is defined as a localized exit of disk material beyond the limits of the original intervertebral space.
Aging↗
Magnetic resonance imaging of hypothalamic hamartomas causing gelastic epilepsy.
Hypothalamic hamartomas may cause a peculiar epileptic syndrome characterized by seizures of laughter and precocious puberty. Four mentally handicapped patients suffering from gelastic epilepsy were referred to our institution for investigation; three of them also presented with precocious puberty. In all four cases magnetic resonance imaging (MRI) revealed a space-occupying lesion of the hypothalamus that was considered to be a hamartoma. Biopsies were not performed. Hamartomas appear isodense in plain computed tomography scans, and they do not enhance. Such lesions display an isointense signal in T1-weighted magnetic resonance images and a hyperintense signal in proton density and T2-weighted images. MRI is the procedure of choice for detecting such lesions at the base of the brain.
Adolescent↗
[Angiolipoma of the central nervous system].
Angiolipomas of the central nervous system are rare tumors (37 cases in the literature) and are mostly located in the spine (95%), rarely in the skull. When they are intraspinal, these masses are extradural in more than 90% of the cases. Angiolipomas are benign tumors containing vascular and mature adipose elements. The clinical symptomatology is non specific, but computed tomography and mostly MRI provide a precise diagnosis. With 2 additional cases and a review of the literature, we define the main characteristics of these tumors.
Adult↗