The Variable Appearance of Third Ventricular Colloid Cysts: Correlation with Histopathology and the Risk of Obstructive Ventriculomegaly.

BACKGROUND AND PURPOSE: While third ventricular colloid cysts may present as an incidental finding, they also harbor the potential to cause ventricular obstruction and sudden death. Herein we analyze the relationship between imaging appearance and the risk of obstructive ventriculomegaly. MATERIALS AND METHODS: This is a retrospective review of the MR imaging appearance of 64 patients with colloid cysts, 46 of whom also had a CT scan, obtained by a tertiary hospital imaging report data base search over a 10-year period. Cysts were categorized by appearance on T2-FLAIR and correlated with patient age, cyst size, and the risk of obstructive ventriculomegaly. Histopathologic correlation was available for 28 cases. RESULTS: The 64-patient cohort was 52% female, median age 50 years (range 10 to 99 years). Cysts hyperintense on T2-FLAIR (53.1%) were larger (P <.001), occurred in younger patients (P = .01), and had a higher risk of obstructive ventriculomegaly than homogeneously hypointense cysts (relative risk 6.18, 95% CI [2.04, 18.67]). Three patterns of T2 hyperintensity were identified: homogeneously hyperintense, hyperintense rim, and cysts with "dot sign." Although "dot sign" cysts were larger (P < .001), there was no significant difference in patient age or the risk of ventricular obstruction among T2 hyperintense cysts. Cyst wall histopathology did not vary with imaging appearance. CONCLUSIONS: Hyperintensity on T2-FLAIR, whether homogeneous, rim, or "dot sign," is associated with larger cyst size and younger patient age, and is an imaging risk factor for obstructive ventriculomegaly. The hyperintense rim does not represent a thickened cyst wall.

Proton spectroscopy and diffusion imaging on the first day of life after perinatal asphyxia: preliminary report.

BACKGROUND AND PURPOSE: MR techniques have proved useful in assessing brain injury from perinatal asphyxia when the injury is subacute or chronic. Recent advances in understanding the molecular mechanisms of brain injury have made medical intervention plausible, creating a need for assessment of the brain within the first few hours of life. We report the results of early (first 24 hours after birth) MR imaging in seven patients, including proton MR spectroscopy in six. METHODS: MR studies were performed within the first 24 hours of life in seven consecutive patients who were encephalopathic after complicated deliveries. Standard T1-, T2-, and diffusion-weighted sequences were performed in all patients; single-voxel MR spectroscopy was performed in two locations in six of the seven patients. Follow-up MR studies were performed in four patients at ages 7, 8, 9, and 15 days, respectively. RESULTS: T1-weighted images were normal in all seven patients. T2-weighted images were normal in three patients and showed T2 prolongation in the basal ganglia or white matter in the other four. Diffusion images showed small abnormalities in the lateral thalami or internal capsules in all seven patients. Comparison with clinical course in all seven patients and with follow-up MR studies in four showed that the diffusion images underestimated the extent of brain injury. Proton MR spectroscopy showed substantial lactate elevation in all six of the patients studied. Two patients died in the neonatal period and the other five were left with clinically significant neurologic impairment. CONCLUSION: MR spectroscopy performed in the first 24 hours after birth is sensitive to the presence of hypoxic-ischemic brain injury, whereas diffusion imaging may help identify but underestimate the extent of the injury. Further studies are ongoing in an attempt to expand upon this observation.

Disappearing cervical disc. Case report.

The authors report the case of a 48-year-old woman who experienced spontaneous resolution of a large herniated disc at C6-7. Spontaneous resolution of a herniated lumbar disc was first documented by computerized tomography. This case is another example of a rare spontaneous resolution of a cervical disc herniation documented by magnetic resonance imaging.

Patterns and implications of MR contrast enhancement in perinatal asphyxia: a preliminary report.

PURPOSE: To determine the presence and location of MR contrast enhancement in infants with perinatal asphyxia and to evaluate the utility of enhancement in assessing extent of brain damage. METHODS: Precontrast and postcontrast MR examinations within the first 10 days of life were evaluated in 10 infants with suspected hypoxic-ischemic birth injury. Findings were correlated with clinical birth history and short-term neurologic follow-up. RESULTS: All four infants with MR signal abnormalities and contrast enhancement in the basal ganglia and brain stem had early seizures and profound neurologic deficits at early follow-up. Two infants had abnormal scans but no contrast enhancement; one with MR signal abnormality within the basal ganglia is neurologically healthy at 10-month follow-up, whereas the other, in status epilepticus at the time of imaging at age 2 days, died. Two infants with minimal parasagittal subcortical white matter enhancement had no early seizure activity and only mild developmental delay at early follow-up. Two infants with normal precontrast and postcontrast MR had no early seizures and remain healthy at early follow-up, despite initial clinical parameters similar to more severely injured infants. CONCLUSION: Although the number of patients is small, our results indicate that the presence of contrast enhancement in asphyxiated neonates may indicate more severe brain damage and, hence, a poorer prognosis.

Complications of axial arthropathies.

Involvement of the cervical spine by rheumatoid arthritis may have severe consequences secondary to subluxation, erosive changes, and soft-tissue inflammation. Unfortunately, the severity of radiographic findings may not directly correlate with the occurrence of cervical myelopathy. MRI has emerged as a noninvasive method of assessing the condition of the spinal cord and thecal sac as well as more precisely defining the nature of inflammatory soft-tissue changes that may result in bony erosion and cord compression. Ankylosing spondylitis is an arthropathy that classically involves the axial skeleton. Complications include acute fracture and pseudarthroses of the spine. Rarely, the development of a cauda equina syndrome has been reported. In addition to classic erosive arthropathies affecting the axial skeleton, ossification of the posterior longitudinal ligament may be associated with the development of severe myelopathy. A recently described type of amyloidosis characterized by beta-2 microglobulin deposition has been reported in patients on long-term hemodialysis. Bony erosion is seen in the spine in these patients. A causal relationship between beta-2 microglobulin and hemodialysis spondylarthropathy has yet to be definitely established.