Neuroradiology case of the day. Gliomatosis cerebri.
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Adolescent↗
Biomedical subjects
R D Tien
Publications and source records attributed to R D Tien.
Neuroradiology case of the day. Multifocal inflammatory leukoencephalopathy due to treatment with 5-fluorouracil and levamisole.
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Antineoplastic Combined Chemotherapy Protocols↗
Frontoethmoidal giant cell reparative granuloma.
We present a case of a giant cell reparative granuloma of the frontoethmoidal region that had a large intracranial extraaxial component and was studied with MR. Although rare, giant cell reparative granuloma can be suggested in the correct clinical setting and when MR features suggest a fibrous lesion.
Adolescent↗
Fast spin-echo MR in hippocampal sclerosis: correlation with pathology and surgery.
PURPOSE: To identify the extent of hippocampal sclerosis in temporal lobe epilepsy with fast spin-echo MR and correlate it with histopathologic findings and surgical outcome. METHODS: MR images of 30 patients with temporal lobe epilepsy and pathologically proved hippocampal sclerosis and 30 control subjects were obtained using a fast spin-echo technique with 4000/100/4 (repetition time/echo time/excitations), 16 echo train, 2- to 3-mm section thickness with interleave, 256 x 256 matrix, and 18-cm field of view. Criteria for MR diagnosis of hippocampal sclerosis included hippocampal atrophy diagnosed with MR volumetry and/or T2-weighted signal change. Hippocampal sectional areas were plotted, and T2 signal changes were topographically evaluated to identify the extent of hippocampal sclerosis, which was subsequently correlated with histopathologic findings and surgical outcome. RESULTS: Hippocampal sclerosis was diffuse, involving both hippocampal head and body, in 96.7% of patients (29 of 30 patients). One patient had normal MR findings. Focal hippocampal sclerosis was not seen. Histopathologic findings of hippocampal sclerosis were present in all 29 patients who had abnormal MR findings. Eighty-six percent of patients (18 of 21 patients), who were followed for at least 1 year after temporal lobectomy, were seizure free (81%, 17 of 21 patients) or significantly improved (5%, 1 of 21 patients). CONCLUSION: Fast spin-echo MR enables accurate definition of the extent of hippocampal sclerosis in patients with temporal lobe epilepsy. All cases of hippocampal sclerosis identified in this study involved the hippocampus diffusely. However, leaving the posterior portion of the hippocampus during surgery does not seem to be a major factor influencing surgical outcome.
Adolescent↗
Cerebral amyloid angiopathy presenting as a brain mass.
The MR images of a patient with cerebral amyloid angiopathy (a localized vascular deposition of amyloid without evidence of systemic amyloidosis) showed an extensive right temporoparietal lobe mass with frontal lobe extension that was slightly hypointense on T1-weighted images and heterogeneously hyperintense on T2-weighted images. No contrast enhancement was identified on MR imaging.
Brain Neoplasms↗
Neuroimaging findings in rare amebic infections of the central nervous system.
The imaging findings in a case of panamebic meningoencephalitis and in a case of granulomatous amebic encephalitis, two rare infections of the central nervous system caused by amebae, are presented and the world literature is reviewed. The brain CT findings in panamebic meningoencephalitis are nonspecific; our case showed diffuse edema. In the case of granulomatous amebic encephalitis, there was evidence of large arterial occlusions and MR demonstration of spinal cord infarctions.
Amebiasis↗
Cerebral phaeohyphomycosis complicated with brain abscess: a case report.
Cerebral phaeohyphomycosis is used to describe the rare clinical syndrome of cerebral infection caused by dematiaceous (i.e. pigmented olivaceous-brown) fungi. It usually presents as brain abscess. In view of the rarity of this fungal infection and its clinical importance, we report a case of cerebral phaeohyphomycosis caused by Xylohypha bantiana. The patient presented with a seizure attack. The MRI study revealed a ring-enhancing lesion with marked perifocal edema in right high frontoparietal junction of the brain. He underwent an initial craniotomy for removal of the lesion and a second craniotomy for recurrence of the lesion 3 months later. The diagnosis was based on successful cultivation of X. bantiana from the surgical specimen and on histopathology. The patient received antifungal drug therapy of 5-flucytosine and itraconazole. He has done well without any symptoms. We think complete surgical removal of the brain abscess combined with antifungal drug therapy is the best management for this rare fungal disease.
Brain Abscess↗
Ethmoid mucocele in an infant with a benign fibroosseous lesion.
We present a case of ethmoid mucocele occurring in a two-month-old child, and associated (presumably causally) with a benign fibroosseous lesion of the ethmoid bone. These two conditions may be more frequently associated than previously recognized; MR greatly facilitates their evaluation.
Diagnosis, Differential↗
Clinical significance of asymmetry of the fornix and mamillary body on MR in hippocampal sclerosis.
PURPOSE: To investigate the clinical significance of MR-defined asymmetry of the fornix and mamillary body for presurgical determination of the side of hippocampal sclerosis in patients with temporal lobe epilepsy. METHODS: Fast spin-echo MR images were evaluated for evidence of an asymmetrically small fornix and mamillary body in 33 patients with pathologically proved hippocampal sclerosis (presurgical hippocampal sclerosis group), 7 patients who had undergone anterior temporal lobectomy (mean, 3 years from surgery) because of hippocampal sclerosis (postsurgical hippocampal sclerosis group), and 34 healthy subjects (control group). Fast spin-echo hippocampal volumetry was performed in each patient. RESULTS: In the control group, 6% (2 of 34) of subjects had MR evidence of asymmetrically small fornix and none (0 of 34) of the subjects had asymmetrically small mamillary body. In the patient population, an asymmetrically small fornix was seen in 42% of presurgical hippocampal sclerosis group, 39% (13 of 33) ipsilateral, and 3% (1 of 33) contralateral, and in 71% of the postsurgical hippocampal sclerosis group (5 of 7), all ipsilateral. In the presurgical hippocampal sclerosis group, hippocampal atrophy measured with MR was more severe in patients with an ipsilaterally small fornix than in patients without. An asymmetrically small mamillary body was found ipsilaterally in 3% (1 of 33) of the presurgical hippocampal sclerosis group and in 57% (4 of 7) of the postsurgical hippocampal sclerosis group; all patients with an asymmetrically small mamillary body in the postsurgical hippocampal sclerosis group also had an asymmetrically small fornix on the same side. CONCLUSION: In presurgical hippocampal sclerosis patients, an asymmetrically small fornix can be seen ipsilaterally on the side of the hippocampal sclerosis; however, its low frequency, its association with severe hippocampal atrophy only, and the possibility of false-positive results limit its clinical usefulness in determining the side of the seizure focus. An asymmetrically small mamillary body is too rare to be used for presurgical location of hippocampal sclerosis. However, an asymmetrically small fornix and mamillary body are frequently seen on MR images after temporal lobectomy.
Adolescent↗
MRI of papillary meningiomas in children.
We report two cases of papillary meningioma in children. The MRI appearance of this special type of meningioma is described for the first time. Both lesions were dura based and associated with cystic components. We review the literature pertaining to this type of meningioma and discuss the differential diagnosis of the MRI appearance. Because this is a malignant type of meningioma, early diagnosis and surgical intervention are important in the management of patients.
Child, Preschool↗
Arteriovenous malformation mimicking recurrent medulloblastoma.
Magnetic resonance imaging (MRI) is becoming the method of choice for evaluation of central nervous system tumors. However, the sensitivity of this modality raises concern that new lesions in patients previously diagnosed with a brain tumor may not necessarily represent recurrent disease. We report a patient previously treated with surgery, radiotherapy, and chemotherapy for a medulloblastoma who developed a new lesion in the floor of the fourth ventricle. Histologic review following excision revealed an arteriovenous malformation.
Brain Neoplasms↗
The Chédiak-Higashi syndrome: CT and MR findings.
Chédiak-Higashi syndrome (CHS) is a rare autosomal recessive disorder postulated to result from lack of regulation of fusion of the primary lysosomes. In this report we present the MR and CT features of the brain in a patient with known CHS. These findings include diffuse atrophy of the brain with diffuse periventricular decreased density identified with CT, as well as increased signal on the T2-weighted images and lack of enhancement on the T1-weighted images in the periventricular and corona radiata regions.
Atrophy↗
Preliminary results of a modified surface rendering technique in the display of magnetic resonance angiography images.
Maximum intensity projections are the currently accepted method of displaying Magnetic resonance angiography (MRA) data. In this study, we introduce a modified surface rendering method for displaying this same MRA data. The system we have developed is designed to reconstruct three-dimensional (3D) images of vasculature using standard magnetic resonance images. A workstation was used for post-processing that is readily available and inexpensive. Software was written to process the original images and control the commercially available surface rendering algorithm while performing the reconstruction. The standard surface rendering technique was modified by including several velocities of blood flow in the reconstruction. These velocities were assigned varying degrees of translucency, which allow flow information to be included in the reconstructed images. Six subjects were examined using this technique and the images were compared with those from other imaging modalities. This surface rendering method has been shown to produce clearer and more comprehensible images of complex vasculature, both for radiologists, and for physicians of other disciplines. Its success is based on improvements in computing techniques and in acquisition of vascular MR images. The method shows great potential, and with future clinical trials, the true uses of this method will be discovered or confirmed.
Blood Flow Velocity↗
Aspergillosis of the brain and paranasal sinuses in immunocompromised patients: CT and MR imaging findings.
OBJECTIVE: With the increased survival of patients with severe immunosuppression, it has become more important to recognize the various forms of cerebral and craniofacial aspergillosis. Currently, only small series of patients with this infection have been described; the radiographic diagnosis of cerebral and craniofacial aspergillosis has varied and has been relatively nonspecific. The purpose of our study was to identify neuroimaging patterns in patients with cerebral and craniofacial aspergillosis. Recognition of radiographic patterns of aspergillosis may facilitate earlier radiologic diagnosis and prompt therapy. MATERIALS AND METHODS: The imaging and clinical data of eight immunosuppressed patients with cerebral aspergillosis and one patient each with aspergillosis of the orbit, paranasal sinus, and calvaria were evaluated retrospectively. All patients were at risk of developing infection by virtue of poorly controlled diabetes or other types of congenital or acquired immunosuppression (e.g., steroids, chemotherapy). Patients were selected for study if the diagnosis of aspergillosis was established by means of biopsy or autopsy and CT scanning or MR imaging was available for review. CT scans and MR images were compared by two experienced neuroradiologists, who were aware of the diagnosis of aspergillosis, to see if common radiographic patterns could be identified that could be used as predictors of this type of infection. RESULTS: Five patients with cerebral aspergillosis had multiple ring-enhancing lesions consistent with abscesses. Characteristic findings were multiple lesions, an irregular ring of contrast enhancement, and hypointensity of the ring on T2-weighted MR images. Three patients had cortical and subcortical hypodensities on CT scanning or hyperintensities on MR imaging consistent with cerebral cortical and subcortical infarction. Two of these three had superimposed hematoma formation. Three patients had craniofacial aspergillosis. One patient each had enhancing mucosal thickening of the paranasal sinus with secondary intracranial dural enhancement, abnormal enhancement of the optic nerve and sheath with infiltrating enhancing soft tissue within the intraorbital fat, and an enhancing diploetic lesion of the calvaria with underlying dural enhancement. CONCLUSION: Three different neuroimaging patterns of cerebral aspergillosis were identified in immunosuppressed patients. The first pattern was multiple areas of hypodensity on CT scans or hyperintensity on T2-weighted MR images involving the cortex and/or subcortical white matter consistent with multiple areas of embolic infarction. This pattern could be seen with or without superimposed hemorrhage, identified as hyperdensity on CT scans or as hyperintensity on T1-weighted MR images. The second pattern was multiple intracerebral ring-enhancing lesions consistent with abscesses. The ring was irregular and of low signal on T2-weighted MR images. The third pattern was dural enhancement associated with enhancing lesions in the adjacent paranasal sinus structure or calvaria or dural enhancement of the optic sheath with associated optic nerve and intraorbital fat enhancement. Recognition of these three patterns of aspergillosis in immunosuppressed patients may lead to more effective diagnosis and treatment planning.
Adolescent↗
MR imaging of high-grade cerebral gliomas: value of diffusion-weighted echoplanar pulse sequences.
OBJECTIVE: The purpose of this study was to evaluate the usefulness of diffusion-weighted echoplanar MR imaging in the examination of high-grade brain gliomas compared with that of conventional spin-echo (SE) or fast spin-echo (FSE) MR imaging. We hypothesize that diffusion-weighted MR imaging may enable us to differentiate various tumor components on the basis of differences in the diffusion of water. SUBJECTS AND METHODS: Conventional SE and FSE MR images were obtained in 10 patients with high-grade brain glioma. Diffusion-weighted echoplanar MR images were obtained with a head gradient coil capable of providing diffusion-weighted imaging along the cephalocaudal axis. Using SE and FSE MR images as a baseline, we evaluated the diffusion-weighted MR images for usefulness in distinguishing tumor components on the basis of differences in diffusion. RESULTS: Areas of tumor that showed significant enhancement on T1-weighted SE MR images obtained after injection of contrast material were markedly hyperintense on diffusion-weighted images and had a lower apparent diffusion coefficient (ADC) than the ADCs for nonenhancing tumor and peritumoral edema. Cystic or necrotic portions of tumor showed the most signal suppression on diffusion-weighted images and were associated with the highest ADCs. On T2-weighted FSE MR images, areas of hyperintensity observed in white matter oriented parallel to the direction of the diffusion gradient could be differentiated into two patterns on the basis of findings on diffusion-weighted images: areas that showed marked signal suppression with a higher ADC, most likely representing areas of predominantly peritumoral edema, and areas that showed a lesser degree of signal suppression with similar but slightly lower ADCs than those of edema, most likely representing areas of predominantly nonenhancing tumor. CONCLUSION: Diffusion-weighted echoplanar MR imaging is a useful technique for examining high-grade cerebral gliomas. It enabled us to differentiate various components of the tumor (e.g., enhancing, nonenhancing, cystic, or necrotic) and to distinguish areas of predominantly nonenhancing tumor from areas of predominantly peritumoral edema when the abnormality was located in the white matter aligned in the direction of the diffusion-weighted gradient. Diffusion-weighted echoplanar MR imaging appears to be a powerful tool in the characterization of brain neoplasms.
Adolescent↗
Fibromuscular dysplasia of arteries of the head and neck: imaging findings.
Cephalocervical fibromuscular dysplasia is an uncommon vascular disease that affects less than 1% of the population. Although often an incidental finding, patients may present with transient ischemic attacks, cerebral infarctions, or subarachnoid hemorrhage. Fibromuscular dysplasia is usually diagnosed in the fourth or fifth decade of life; it occurs in women more often than in men and in whites more frequently than in blacks. The purpose of this essay is to illustrate the broad spectrum of neuroimaging findings seen on CT scans, MR images, and angiograms of patients with cephalocervical fibromuscular dysplasia. The value of MR imaging in distinguishing tubular fibromuscular dysplasia from arterial dissection and arterial hypoplasia is demonstrated.
Adult↗
MR imaging of diseases of the limbic system.
The limbic system refers to the part of the brain that is involved in emotional expression and in cognitive and somatomotor control systems; it most likely also has a significant role in the pathogenesis of certain dementias, neuropsychiatric disturbances, and seizure disorders. This system, as originally defined, has no clear anatomic boundaries. Limbic regions of the telencephalon include a continuous medial zone of cortical regions, including the hippocampal formation; a perihippocampal zone, including the cingulate gyrus, prefrontal region, and perirhinal region; along with subcortical areas, including the septum pellucidum and the amygdala. A distinguishing characteristic of the limbic region is that it is highly interconnected and appears to form the only major route for information transfer between the neocortex and the hypothalamus. With the multiplanar capability and resolution of MR imaging, the individual parts of the limbic system and the diseases that affect them can be studied. In this review, we discuss MR imaging of the diseases that affect this system.
Brain Diseases↗
MR measurements of the hippocampus for lateralization of temporal lobe epilepsy: value of measurements of the body vs the whole structure.
OBJECTIVE: Measurements of the volume of the hippocampus have been used preoperatively to determine the side of the hippocampus involved in patients with intractable temporal lobe epilepsy. However, the method used is time consuming and requires special training. The purpose of this study was to determine the validity of using measurements of the volume of the hippocampal body as a substitute for measurements of the volume of the whole hippocampus in patients with temporal lobe epilepsy. SUBJECTS AND METHODS: The study group consisted of 33 patients with intractable temporal lobe epilepsy due to presumed hippocampal sclerosis and 30 control subjects. Of the 33 patients with intractable temporal lobe epilepsy, 30 had hippocampal sclerosis and three had normal findings on pathologic examination of the hippocampus. T2-weighted fast spin-echo images were used to determine hippocampal volumes. Volumes were calculated by summing the sectional areas of the entire hippocampus and of the hippocampal body. Correlation between the volume of the hippocampal body and the volume of the whole hippocampus was determined. The sensitivity and specificity of measurement of the volume of the hippocampal body for lateralizing the foci responsible for seizures in patients with presumed hippocampal sclerosis were compared with those of measurement of the volume of the whole hippocampus. RESULTS: Significant linear relationships were noted between volumes of the hippocampal body and volumes of the whole hippocampus (p < .001). The sensitivity and specificity of measurements of volumes of the hippocampal body were identical to those of measurements of volumes of the whole hippocampus (87% and 100%, respectively). CONCLUSIONS: Our results show that segmental MR measurements of the body of the hippocampus are as accurate as measurements of the whole hippocampus for lateralizing temporal lobe epilepsy before surgery. Because segmental measurements are less time consuming and require less experience to perform, they are considered the procedure of choice.
Adolescent↗