Signal Intensity In Periventricular White Matter Research Articles

MRI and proton spectroscopy in children with late infantile neuronal ceroid lipofuscinosis: Preliminary results

Aim of the study was to characterize findings on magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy ( 1 H-MRS) in children with late infantile neuronal ceroid lipofuscinosis (NCL) and the relationship between these results and duration of the disorder. Three children with late infantile NCL and six age-matched controls were examined with MRI and by localized 1 H-MRS. Voxel regions studied were periventricular frontal white matter, thalami and cerebellar deep white matter. N-acetylaspartate/creatine (NAA/Cr) and choline/creatine (Cho/Cr) ratio was calculated. MRI showed various degrees of cortical atrophy and increased periventricular white matter signal intensity on T2- and -fluid attenuated inversion recovery-weighted images. There was no significant volume loss in the brainstem. Metabolic ratio (NAA/Cr and Cho/Cr) showed progressive decrease with longer disease duration in thalamic and cerebellar voxels and exhibited a negative relationship in frontal voxels. In conclusion, the most significant changes on neuroimaging in late infantile NCL are progressive cortical and cerebellar atrophy, which are more pronounced in the cerebellum. Decreased signal intensity in the thalami may also be observed as in other forms of NCL. 1 H-MRS is the most sensitive method for measuring metabolic changes. The decreased level of NAA although

Magnetic Resonance and Cranial Ultrasound Characteristics of Periventricular White Matter Abnormalities in Newborn Infants

OBJECTIVE: To characterize the range of abnormalities within the periventricular white matter (PVWM) in a cohort of newborns using magnetic resonance (MR) brain imaging and to compare the focal MR abnormalities with the cranial ultrasound (CUS) findings. METHODS: Retrospective study of MR brain and CUS findings of infants born in the 18-month period 1998-1999. PVWM abnormalities were identified by MR and focal lesions were characterized by size, number and distribution using a grading scale. Correspondence with CUS findings was assessed. RESULTS: 175 MR examinations corresponding to n=105 preterm infants, (median GA 28, range 23–36 weeks) andn=25 term infants (median GA 39, range 37–42 weeks) were analysed for PVWM abnormalities. In the preterm group, MR demonstrated a normal PVWM in n=76, focal areas of altered signal intensity (SI) in PVWM in n=26 and venous infarction inn=3. In the term group, MR demonstrated a normal PVWM in n=15, focal areas of altered SI in PVWM in n=4, oedematous PVWM in n=2 and a middle cerebral artery infarction in n=4. All infants with normal MR had normal CUS findings. A focal PVWM SI abnormality detectable on MR corresponded with an abnormality on CUS in onlyn=10/30. CONCLUSIONS: MR appears considerably more sensitive than CUS in demonstrating the existence and extent of focal PVWM lesions in newborn infants. Satisfactory correspondence between the two imaging investigations is obtained only for cystic PVWM lesions. Childs, A.-M.et al. (2001)Clinical Radiology56, 647–655.

Regression of HIV encephalopathy and basal ganglia signal intensity abnormality at MR imaging in patients with AIDS after the initiation of protease inhibitor therapy.

To determine whether protease inhibitors cause regression of periventricular white matter signal intensity abnormalities in patients with human immunodeficiency virus (HIV) encephalopathy and whether the changes on magnetic resonance (MR) images correlate with cognitive improvement. MR images were retrospectively and prospectively analyzed in 16 adult patients with HIV encephalopathy. White matter and basal ganglia signal intensity abnormalities on initial long repetition time (TR) images were compared with those on subsequent long TR images in patients who received and in patients who did not receive protease inhibitors. Clinical correlation was obtained. Of the nine patients receiving protease inhibitors, four showed nearly complete regression, four showed interval stability, and one showed slight progression. Thus, eight patients (89%) demonstrated either stability or improvement in white matter disease, which correlated with cognitive improvement. Of the seven patients not receiving protease inhibitors, six (86%) showed marked progression with a decline in cognitive function and one had no interval change. The difference between the two groups was statistically significant. Of the two patients receiving protease inhibitors who initially had basal ganglia signal intensity abnormalities, one demonstrated resolution and one nearly complete resolution subsequently. Although the patient population is small, protease inhibitors may cause regression of periventricular white matter and basal ganglia signal intensity abnormalities in HIV encephalopathy and may have a role in treatment.

Central nervous system effects of chronic toluene abuse—Clinical, brainstem evoked response and magnetic resonance imaging studies

We describe the results of neurological evaluation, magnetic resonance imaging (MRI) of the brain and brainstem auditory evoked response (BAER) testing in 11 chronic toluene vapor abusers. Neurological abnormalities were seen in four of 11 individuals and included cognitive, pyramidal, cerebellar and brainstem findings. MRI of the brain was abnormal in three of 11 individuals and revealed the following abnormalities: 1) Diffuse cerebral, cerebellar, and brainstem atrophy; 2) Loss of differentiation between the gray and white matter throughout the CNS; and 3) Increased periventricular white matter signal intensity on T2 weighted images. BAERs were abnormal (control mean ±3 S.D.) in five of 11 individuals. As a group, the latency of V ( p<0.01), the III–V interpeak ( p<0.05) and the I–V interpeak latencies were prolonged compared to controls. All three individuals with abnormal MRI scans also had abnormal neurological examinations and BAERs. Two of five individuals with abnormal BAERs, however, had normal neurological examinations and MRI scans. Our data support previous findings of diffuse white matter involvement in chronic toluene abusers and suggest that BAERs may detect early CNS injury from toluene inhalation even at a time when neurological examination and MRI scans are normal. BAERs, therefore, may be a sensitive screening test to monitor individuals at risk from toluene exposure (either abusers or industrially exposed individuals) for early evidence of CNS injury.

Toluene abuse causes diffuse central nervous system white matter changes

We describe the findings of magnetic resonance imaging (MRI) of the brain in 6 chronic toluene vapor abusers and the neuropathological findings in 1 abuser not studied by MRI. MRI in 6 chronic toluene abusers revealed the following abnormalities: (1) diffuse cerebral, cerebellar, and brainstem atrophy; (2) loss of differentiation between the gray and white matter throughout the central nervous system; and (3) increased periventricular white matter signal intensity on T2-weighted images. Another chronic toluene abuser (MRI not performed) died as a result of acute toluene overdose. The brain displayed diffuse, ill-defined myelin pallor, maximal in cerebellar, periventricular, and deep cerebral white matter. Neurons were preserved throughout, axonal swelling or beading was not seen, gliosis was minimal, and occasional, scant perivascular macrophage collections were seen. Taken in concert, these findings suggest that the pathological and MRI abnormalities are due to either increased water content of the white matter or subtle toluene-induced metabolic changes in myelin.