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 <one year after onset. Cell count, protein levels, polymerase chain reaction (PCR) of herpes simplex virus in cerebrospinal fluid (CSF), and exacerbation of neurological symptoms as well as dose of acyclovir were compared between patients with and without white matter abnormalities. Diffuse white matter signal changes were identified at the subacute stage (3-5 weeks after onset) of HSE in six patients (6/15, 40%). No significant relationship was observed between the presence of white matter signal abnormalities and laboratory data, acyclovir dose or clinical symptoms. These signal abnormalities disappeared or improved by two years without any clinical treatment. Diffuse white matter signal abnormalities occur frequently in the subacute stage of HSE. Although the mechanisms underlying these white matter lesions have not been elucidated, subclinical immune-mediated processes may be considered. Repeat MRI studies over a long period are necessary for evaluating the clinical process of patients with HSE.

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.

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.

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.

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.