Imaging-pathologic correlation in corticobasal degeneration.

BACKGROUND AND PURPOSE: The clinical diagnosis of corticobasal degeneration (CBD) is often difficult due to varied clinical manifestations. In 4 patients with neuropathologically confirmed CBD, characteristic imaging findings and correlations with neuropathologic features were evaluated. Furthermore, imaging findings in CBD were compared with neuropathologically confirmed progressive supranuclear palsy (PSP) for a differential diagnosis. MATERIALS AND METHODS: Four patients with neuropathologically confirmed CBD were studied. We evaluated the area of the tegmentum in the midsagittal plane, subcortical white matter (SCWM) abnormality, asymmetric cerebral atrophy, and signal-intensity abnormality in the subthalamic nuclei on MR imaging and compared them with histopathologic findings. Then, MR imaging findings in CBD were compared with those in 13 patients with PSP. RESULTS: On MR imaging, 3 patients had asymmetric cerebral atrophy extending to the central sulcus. On midsagittal sections, the mean midbrain tegmentum area was 66 mm(2), being markedly smaller than normal, but there was no significant difference between PSP and CBD. All patients had signal-intensity abnormalities of the SCWM, constituting primary degeneration neuropathologically; however, no diffuse signal-intensity abnormality in the SCWM existed in the 13 patients with PSP. In 3 patients, T1-weighted images showed symmetric high signal intensity in the subthalamic nuclei. Neuropathologically, these areas showed characteristic CBD. MR imaging signal-intensity changes also existed in 4 patients with PSP; however, subthalamic nucleus degeneration was more severe in PSP than in CBD. CONCLUSIONS: In cases with midbrain tegmentum atrophy and signal-intensity changes in the subthalamic nuclei, the differential diagnosis distinguishing CBD from PSP based on MR imaging alone was difficult. White matter lesions and asymmetric atrophy can be useful for a differential diagnosis.

Significance of radio-pathological correlations: differentiating severe central nervous system infection from acute embolic infarction.

We describe two educational autopsy cases of severe central nervous system (CNS) infection and septic emboli, such cases having been difficult to differentiate from acute infarctions via emergency MR imaging studies. We briefly discuss the pathology and MR findings along with radiopathological correlation.

Asymptomatic self-limiting diffuse white matter lesions in subacute to chronic stage of herpes simplex encephalitis.

This study evaluated white matter changes in the subacute and chronic stages of herpes simplex encephalitis (HSE). Subjects comprised 15 patients with HSE. All patients were examined using MRI at onset, and then at seven to ten days, three to five weeks and two to three months after onset. In addition, the six patients who displayed white matter signal abnormalities were examined at six months and

Optic nerve hyperintensity on T2-weighted images among patients with pituitary macroadenoma: correlation with visual impairment.

PURPOSE: Visual acuity (VA) disturbance other than field defect is important in evaluating patients with pituitary macroadenoma. The purpose of this study was to evaluate MR imaging appearances of optic nerves in patients with pituitary macroadenoma and to ascertain whether visual impairment was correlated with abnormality in optic nerve signal intensity. PATIENTS AND METHODS: Twenty-seven patients with pituitary macroadenoma were examined. Optic nerves were evaluated on T2-weighted images and correlations of signal intensity abnormality with VA disturbance, visual field disturbance, degree of optic chiasm compression, pathologic findings of surgical specimen, and disease duration were statistically analyzed. Correlations between recovery of VA after treatment and the above-mentioned factors were also determined. RESULTS: Coronal T2-weighted images demonstrated unilateral optic nerve hyperintensity lesions in 9 patients. Bilateral signal intensity abnormality of the optic nerve was seen in 5 patients. Signal intensity abnormality of the optic nerve was seen at the site of compression and in the ventral side of the tumor. These patients did not demonstrate signal intensity abnormality posterior to the tumor. Presence of such signal intensity abnormalities was correlated with the degree of optic chiasmal compression and with VA disturbance. Recovery of VA after treatment was correlated with disease duration. CONCLUSION: Hyperintensity of the optic nerves ventral to the pituitary macroadenoma was associated with VA impairment. Recovery of VA after treatment was correlated with disease duration. MR imaging of the optic nerves can provide valuable information for management of pituitary macroadenoma.

Vascular endothelial growth factor expression in pituitary adenomas.

Vascular endothelial growth factor (VEGF) is known to be a mediator of angiogenesis and vascular permeability. A cystic component and hemorrhage are often found in pituitary adenomas. In the present study we assess the VEGF expression based on immunohistochemical examinations in 48 pituitary adenomas. All the adenomas showed some VEGF immunoreactivity mainly in the cytoplasm of tumor cells. Of the 48 adenoma-cases, 16 cases had a strong VEGF immunoreactivity, 26 cases had a moderate one, and 6 cases had a weak one. On the MR images, a cystic component was found in 16 cases (33.3%), and a hemorrhage was found in 18 cases (37.5%). The VEGF immunoreactivity had a significant relationship with the cystic component but neither the hemorrhage, size, recurrence, or HE classification. These findings suggest that VEGF might play a potential role in the pathogenesis of cystic formation in pituitary adenomas.

Primary Sjögren's syndrome initially manifested by optic neuritis: MRI findings.

We herein describe the MRI findings in a patient clinically diagnosed with primary Sjögren's syndrome (SjS) initially manifested by retrobulbar optic neuritis. A 63-year-old woman suddenly had left ocular pain and progressive visual disturbance. MR T2-weighted images revealed hyperintensity in the left optic nerve, with swelling. Contrast-enhanced T1-weighted images showed no abnormal enhancement. Follow-up MRI 6 months after admission revealed no significant changes in the affected optic nerve. To our knowledge, optic neuritis as a complication of SjS has been reported in ten patients [1, 2, 3, 4, 5, 6] and MRI findings in only one of them [6]. We thought MR images were useful for visualizing optic nerve involvement in SjS and observing its course.

Relationship between stroke and asymptomatic minute hemorrhages in hypertensive patients.

Asymptomatic small hemorrhages were identified in hypertensive patients by T2*-weighted gradient echo magnetic resonance (MR) imaging to investigate the relationship between hypertensive intracerebral hemorrhage and asymptomatic minute hemorrhages. Forty-eight patients with hypertensive intracerebral hemorrhage or cerebral infarction with hypertension (these diseases were defined as stroke) were treated in National Defense Medical College from April 1998 to February 2000. All patients had no past history of stroke or head injury, underwent MR imaging within 6 months of the stroke attack, were aged from 40 to 80 years, and had no diagnosis of aneurysm, angioma, or moyamoya disease. Patients were divided into the infarction group and hemorrhage group. All foci over 2 mm in size appearing as hypointense on T2*-weighted MR imaging and unrelated to stroke areas were defined as minute hemorrhages. There were no significant differences between the two groups with respect to sex, age, and history of diabetes mellitus. The incidence of minute hemorrhages in the hemorrhage group (21/26) was greater than in the infarction group (9/22, p < 0.01). The incidence of minute hemorrhages in the basal ganglia (18/26) was greater in the hemorrhage group than in the infarction group (4/22, p < 0.001). Symptomatic intracerebral hemorrhage may be preceded by asymptomatic minute hemorrhage.

[Thallium-201 single photon emission tomography of intracranial angiomas].

We herein describe thallium-201 single photon emission tomography (T1-201 SPECT) findings in three cases with intracranial angioma. One of the lesions which was associated with chronic encapsulated intracerebral hematoma showed moderate accumulation of T1-201, but, others demonstrated no accumulation. The usefulness and limitations of T1-201 SPECT in differential diagnosis of intracranial mass lesions are discussed.

A quantitative analysis of head injury using T2*-weighted gradient-echo imaging.

BACKGROUND: T2*-weighted gradient-echo imaging (T2*-GE) is useful for detecting small hemorrhages. METHODS: Thirty-four patients were prospectively examined, first by magnetic resonance imaging (1.5 T) and then by T2-weighted fast spin echo (T2-FSE) and T2*-GE. Thereafter, the correlations between the T2-FSE or T2*-GE findings and the clinical or computed tomography findings were analyzed. RESULTS: The number of lesions detected by T2*-GE was 14.5 +/- 16.3 (mean +/- SD, n = 34), which was significantly (p < 0.001) greater than that detected by T2-FSE (5.6 +/- 5.6, n = 34). The findings of T2*-GE correlated positively with both the duration of unconsciousness (R2 = 0.74,p < 0.0001) and with Glasgow Outcome Scale (R2 = 0.81, p < 0.0001), whereas those of T2-FSE did not show any significant correlation. T2*-GE imaging could also detect all areas responsible for focal neurologic signs 1 month after in. jury, whereas T2-FSE imaging detected only 22 of 33 such signs. CONCLUSION: T2*-GE was found to be useful for evaluating the clinical symptoms of head injury.

The evolution of cerebral blood flow in the developing brain: evaluation with iodine-123 iodoamphetamine SPECT and correlation with MR imaging.

BACKGROUND AND PURPOSE: Although it is well established that brain maturation correlates temporally with the functions the newborn or infant performs at various stages of development, the precise relationship between function and anatomic brain maturation remains unclear. The purpose of this study was to investigate the developmental changes of regional cerebral blood flow (rCBF) in infants and children using iodine-123 iodoamphetamine (123I-IMP) and single-photon emission computed tomography (SPECT). These findings were correlated with the MR imaging appearance of the brain and with known developmental changes. METHODS: Twenty-one 123I-IMP SPECT examinations of 17 patients, ranging in age from neonates to 2 years, were reviewed retrospectively. All children had had transient neurologic events in the neonatal period that did not significantly affect subsequent neuropsychological development. MR studies were performed in 12 of these patients and the MR findings were correlated with the SPECT results. RESULTS: SPECT studies showed a consistent pattern of evolving changes in 123I-IMP uptake, most likely reflecting evolution of rCBF. From the 34th postconceptional week until the end of the second month after term delivery, there was predominant uptake in the thalami, brain stem, and paleocerebellum, with relatively less cortical activity. Radionuclide uptake in both the perirolandic and occipital cortices was well seen around the 40th postconceptional week and increased rapidly thereafter, with a predominance of parietal activity. By 3 months, radionuclide uptake in the cerebellar hemispheres and parietofrontal cortices increased. Frontal and temporal activity increased by age 6 to 8 months. Uptake in the basal ganglia increased by 8 months. By the beginning of the second year, rCBF showed a similar topographic pattern to that in adults. CONCLUSION: The time course of the changes in 123I-IMP uptake in the developing brain as detected by SPECT is similar to that of myelination and most likely reflects an overall topologic maturational pattern of the brain.

Focal cortical dysplasia: appearance on MR images.

PURPOSE: To clarify the magnetic resonance (MR) imaging characteristics of focal cortical dysplasia (FCD). MATERIALS AND METHODS: The authors reviewed the MR images of 14 patients with FCD, which was confirmed with histologic examination. RESULTS: MR images exhibited FCD in 13 of the 14 patients. All lesions were localized to part of one hemisphere. T2-weighted images showed blurring of the gray matter-white matter junction and abnormal signal intensity in the white matter in 11 patients. T1-weighted images showed blurring of the gray matter-white matter junction in seven patients, broad gyri in nine, thick cortices in nine, abnormal sulci in 10, and focal enlargement of the overlying subarachnoid space or adjacent ventricle in eight. Surgical specimens exhibited disruption of cortical lamination without abnormal gyration in all patients, cytomegalic neurons in the cortex in three, disorganized bizarre glial cells in the cortex in seven, ectopic neurons or bizarre glial cells in the white matter in nine, and blurring of the gray matter-white matter junction in one. CONCLUSION: Blurring of the gray matter-white matter junction with abnormal signal intensity in the white matter on T2-weighted images is characteristic of FCD. The presence of ectopic neurons and bizarre glial cells, dysmyelination, and a reduction in the number of myelinated fibers might have been responsible for the MR imaging characteristics.

A case of bilateral reversible thalamic lesions.

We describe a case of bilateral reversible thalamic lesions with no neurological deficits and a good prognosis. The lesions appeared as low-density areas on CT and high-intensity areas on T2-weighted MR imaging, and resolved within 1 month, suggesting that the cause was edema.

Corticobasal degeneration: MR with histopathologic comparison.

The purpose of this study was to illustrate the MR findings of corticobasal degeneration and to compare those findings with pathologic specimens. MR findings of atrophy in the perirolandic gyri, atrophy of the basal ganglia, and T2 prolongation in the posterolateral putamen are useful evidence supporting the clinical diagnosis of corticobasal degeneration.

Skull base and calvarial deformities: association with intracranial changes in craniofacial syndromes.

PURPOSE: To analyze the skull and brain malformations in patients with craniofacial syndromes. METHODS: A retrospective analysis of imaging studies of 21 children with craniofacial anomalies (8 with Apert syndrome, 6 with Pfeiffer syndrome, 4 with Crouzon syndrome, 1 with Robert syndrome, 1 with Coffin-Lowry-syndrome, and 1 with Saethre-Chotzen syndrome) was carried out using CT (21 patients), MR imaging (9 patients), and MR venography (2 patients). A series of qualitative and quantitative assessments of the skull base and intracranial structures was performed. RESULTS: Skull base abnormalities were present in all patients. Intracranial abnormalities included ventriculomegaly, frank hydrocephalus, callosal anomalies, hypoplasia/absence of the septum pellucidum, hypoplasia/dysplasia of the hippocampus, dysplasias or distortions of the cerebral cortex, and parenchymal hemorrhage. The anomalies of the corpus callosum, septum pellucidum, and hippocampus appeared primary, whereas the others may have been the result of brain distortion by the calvarial anomaly. MR imaging was more useful than CT for evaluating brain abnormalities. In the two patients in whom it was performed, MR venography showed anomalies of the venous system, indicating that venous anomalies, possibly related to the skull base hypoplasia, may contribute to the intracranial abnormalities. CONCLUSION: A wide range of neuroimaging abnormalities are present in the craniofacial syndromes. Some of these are clearly primary, whereas others appear to be related to the small skull base and sutural synostoses. MR venography may prove useful in defining the cause of some of the associated anomalies.

Apogeotrophic type of direction-changing positional nystagmus related to slow vertebrobasilar blood flow.

We examined the incidence of slow blood flow (SBF) in the vertebrobasilar system by magnetic resonance imaging (MRI) in 35 patients showing direction-changing positional nystagmus (DCPN). The subjects consisted of 20 patients with apogeotrophic type (group A) and 15 with geotrophic type (group B) of DCPN. Fifty-seven age-matched subjects without vestibular symptoms were examined as a control group (group C). SBF was detected in 11 (55%), 3 (20%) and 6 (11%) patients in groups A, B and C, respectively. Lacunae of the brainstem were found in 7 (35%) patients in group A and 1 (7%) in group B. The higher incidence of SBF in group A suggested a possible relationship between SBF and apogeotrophic type of DCPN. Apogeotrophic type of DCPN associated with SBF was considered to be caused by ischemia in the posterior circulation, though it was unclear whether the vestibular labyrinth or the hindbrain was mainly involved.

Ischemic brain lesions in aged patients with dizziness.

OBJECTIVE: To compare neuro-otological test results in aged patients complaining of dizziness with their magnetic resonance imaging findings. DESIGN: The presence of lacunar infarcts of the hind-brain was used as a gold standard. SETTING: A department of otolaryngology in a regional general hospital. PATIENTS: All patients over 60 years old with dizziness during a period of 1 year 2 months, excluding those with central lesions of other than vascular origin (n=48). RESULT: Lacunar infarcts were found in 22 patients: the cerebellum for two patients, the brain stem for 17, and both regions for three. Patients with lesions of the cerebellum or the lower brain stem showed central vestibular abnormalities, whereas eight patients with only the upper brain-stem lacunae did not. A canal paresis was found in 12 of 20 patients with the brain-stem lacunae. Patients without lesions in the posterior fossa did not show significant abnormalities, indicating central disorders. CONCLUSION: This study documents a high prevalence of lacunar infarcts of the hindbrain in patients over 60 years old with dizziness, and it also demonstrates the difficulty in detecting small lesions of only the upper brain stem by neuro-otological tests. This calls attention to a differential diagnosis in aged patients with dizziness.

Sudden sensorineural hearing loss associated with slow blood flow of the vertebrobasilar system.

To determine the characteristics of sudden deafness associated with slow blood flow (SBF) within the vertebrobasilar arteries, we evaluated 57 patients with sudden deafness using magnetic resonance imaging (MRI). We detected SBF in 12 (21%) patients, predominantly men over 50 years of age. A second MRI performed in 5 patients 2 months after the onset of symptoms showed recovery of blood flow. All 12 patients complained of vertigo. Audiological and neurotologic tests suggested that hearing loss mainly involved the inner ear. Our findings suggest that unless central lesions are detected, headache, hypoesthesia of the external ear canal, and electronystagmographic abnormalities are signs of SBF. Because sudden deafness may recur in patients who have SBF, they should be monitored and treated to prevent recurrence.

Slow blood flow of the vertebrobasilar system in patients with dizziness and vertigo.

We evaluated 102 patients with dizziness or vertigo who were 50 years of age and over, using magnetic resonance imaging (MRI). Slow blood flow (SBF) in the vertebrobasilar system was detected in 36 patients (35%). The patients with SBF experienced dizziness or vertigo for a longer period than those without SBF. The apogeotrophic type of direction-changing nystagmus was observed in 10 of 36 patients with SBF. No significant differences were found between patients with and without SBF with other neurotological tests. Because MRI can detect both infarcts in the hind-brain and SBF in the vertebral and basilar arteries it is recommended for evaluation of vascular disorders in older patients with vestibular symptoms.