Characteristics of intravascular large B-cell lymphoma on cerebral MR imaging

IVL is characterized by a propensity for intravascular tumor cell proliferation. Premortem diagnosis of IVL is difficult because of its nonspecific clinical, laboratory, and imaging manifestations. This study examined cerebral MR imaging patterns of IVL and their changes with and without chemotherapy. Nine of 11 patients studied presented with abnormal findings. We define 5 patterns of abnormal MR imaging findings: 1) infarctlike lesions, 2) nonspecific white matter lesions, 3) meningeal enhancement, 4) masslike lesions, and 5) hyperintense lesions in the pons on T2WI. Seven patients presented with only 1 pattern, while 2 patients presented with multiple patterns. Lesions in 7 treated patients responded to chemotherapy. Pathologic specimens revealed intravascular tumor cell infiltration with associated infarctions, necrosis, congestion, demyelination, vasculitis, and tumor cell extravasation. We conclude that MR imaging patterns can be possible manifestations of intravascular-dominant infiltration by tumor cells with associated occlusion or inflammation, depending on the level of affected vessels.

High signal of the striatum in sporadic Creutzfeldt-Jakob disease: sequential change on T2-weighted MRI

The object of this study is to describe the sequential change of high signal of the striatum on T2-weighted MRI in sporadic Creutzfeldt-Jakob disease (CJD). Three cases of autopsy-proven sporadic CJD and a total of 18 serial MR images are included in this study. The degree of high signal of the striatum on T2-weighted MRI was evaluated by two neuroradiologists and divided into four grades by mutual agreement. Initial MRI of all three cases showed a slightly high signal of the bilateral striatum, and the conspicuity of the high signal became more prominent as the disease progressed. In each case the pathological change of striatum and globus pallidus was compared with the high signal on the last MR image.

Usefulness of gradient-echo T2*-weighted MR imaging in evaluation of transorbital penetrating cerebral injury

Transorbital penetrating cerebral injury can cause severe morbidity if not identified and treated. After the removal of the object and without the clinical information, even the chance of suspicion of penetrating cerebral injury might be missed in the first investigation. We report a case of transorbital penetrating cerebral injury caused by a metal rod and diagnosed by MRI including gradient-echo T2*-weighted imaging.

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.

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.

Phosphorus-31 nuclear magnetic resonance in vivo spectroscopy of human liver during hepatitis A virus infection

To evaluate the changes in hepatocellular phospholipid metabolism during hepatitis virus infection, 26 patients with acute viral hepatitis A were studied by means of phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. The spectroscopy of liver showed six signal components in all patients as well as in the normal volunteers. During the early phase of illness, the phosphomonoester (PME)-phosphodiester (PDE) ratios in the patients became markedly greater than the ratios in the controls (P < 0.001). Within six weeks after the onset, the PME/PDE ratios returned to the level of controls. The time course analysis indicated an inverse correlation between the PME/PDE ratio and the period of time after onset (r = 0.738, P < 0.001). The spectral changes of human liver observed in acute viral hepatitis A are similar to those in the regenerating rat liver, indicating that 31P-NMR spectroscopy allows a noninvasive study of cell turnover in human liver disease associated with acute virus infection.

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.

Assessment of brain death in children by means of P-31 MR spectroscopy: preliminary note. Work in progress

The authors examined the possibility of assessing cerebral damage with phosphorus-31 magnetic resonance (MR) spectroscopy in 24 patients (three infants, four children older than age 5 years, and 17 adults) who met the adult criteria for brain death. In all patients except patient 3 (an infant 8 months old), inorganic phosphate with phosphodiester was observed, and adenosine triphosphate (ATP) and phosphocreatine (PCr), which are detectable in healthy brains, were not detected. In 22 of these 23 patients, cardiac death occurred within 7 days after clinical brain death, and in one infant 14 months old, cardiac death occurred 38 days after clinical brain death. In patient 3, ATP and PCr were detected with P-31 MR spectroscopy, and now, more than 20 months after brain death, cardiac death has not yet occurred. In children younger than age 5 years, P-31 MR spectroscopic findings were predictive of the patient's clinical outcome. These findings may help establish criteria for the diagnosis of brain death in children younger than age 5 years.

Prominent meningeal enhancement adjacent to meningioma on Gd-DTPA-enhanced MR images: histopathologic correlation

To assess tissue changes responsible for enhancement of the meninges adjacent to meningiomas on magnetic resonance (MR) images, the authors correlated the MR imaging characteristics of meningeal lesions seen before and after administration of gadolinium diethylenetriamine-pentaacetic acid (DTPA) with the appearance of these lesions on contrast material-enhanced computed tomographic (CT) images and with histopathologic findings in four patients. Histopathologic examination of meninges showed increased loose connective tissue, hypervascularity, and dilated vessels. There was neoplastic infiltration of the dura mater in two patients but it was restricted to the immediate junction of neoplasm and dura mater, with maximum peripheral extension within 1 mm of the tumor margin. In both patients the meninges were enhanced far beyond the neoplastic infiltration. The other two patients showed no infiltration of dura mater. These findings suggest that pathologic enhancement of meninges adjacent to meningioma after administration of Gd-DTPA mainly represents reactive changes to the neoplasm and does not necessarily indicate neoplastic involvement.