Search PubMed⌕ Search

Biomedical subjects

M N Paley

Publications and source records attributed to M N Paley.

27 records · Page 2Linked to original sources
PubMed1997

Correlation of MRI and neuropathology in AIDS.

OBJECTIVE: To assess the correlation between findings on radiological and neuropathological examinations of the brain. METHODS: The formalin fixed brains of 19 patients who had died of AIDS were examined by MRI and neuropathology. RESULTS: The rate of identification of cerebral atrophy was similar radiologically and neuropathologically. However, only in half of these cases were the two examinations concordant in the diagnosis. Furthermore, in the 15 brains which had radiological diffuse white matter lesions, the underlying pathology was heterogeneous. CONCLUSIONS: The possible reasons for the inconsistencies, and their relevance to the interpretation of imaging studies, are discussed. The study suggests that the qualitative identification of atrophy in the postmortem brain is problematical and that diffuse white matter lesions seen on MRI are not indicative of a specific pathological process.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Proton MRS and quantitative MRI assessment of the short term neurological response to antiretroviral therapy in AIDS.

OBJECTIVE: To investigate MRI and proton spectroscopy changes in five patients with HIV associated dementia complex (HADC) treated with antiretroviral therapy. METHODS: Three markers were evaluated: (1) CSF/intracranial volume ratio; (2) T2 weighted signal ratio between parieto-occipital white and subcortical grey matter; and (3) metabolite ratios from long echo time (TE=135 ms) single voxel proton spectra of parieto-occipital white matter. RESULTS: Spectroscopic changes indicated initial increases in N-acetyl/(N-acetyl + choline + creatine) ratio (NA/(NA+ Cho+Cr)) and progression of atrophy after initiation of antiretroviral therapy in four of five patients. When the neurological status of the patients subsequently deteriorated (two of five patients), the NA/(NA+Cho+Cr) ratio also declined. CONCLUSIONS: Spectroscopic changes mirror reversible neuronal dysfunction. These objective, non-invasive techniques may be used for monitoring the neurological effects of antiretroviral drug therapy in patients with HADC.

AIDS Dementia Complex↗
PubMed1996

Cerebral magnetic resonance relaxometry in HIV infection.

A prospective, cross-sectional study was designed to determine the magnetic resonance relaxation times of cerebral white matter in human immunodeficiency virus (HIV) infected individuals. T1 and T2 were estimated at 1.5 T using four-point methods. Seventy-five HIV-1 seropositive subjects, 48 seronegative blood donors, and 17 seronegative homosexual men were studied. Associations between relaxometry and clinical classification, neurological status, immunological status, and qualitative MRI were investigated. Statistically significant differences in white matter T1 relaxation time were found comparing low-risk control and AIDS groups (p < .005), seropositive subjects with neurological signs and those without (p < .005), and subjects with low (CD4 < or = 200 x 10(6)/l) and high (CD4 > 200 x 10(6)/1) CD4 cell counts (p < .05). These findings add to the body of information that reveals no HIV-related change in the brain before the onset of symptomatic immunosuppression and go someway to validating the previous visually rated, qualitative findings. Statistically significant difference in white matter T2 relaxation time were also found comparing the two control groups (p < .005) highlighting the need for appropriate controls.

AIDS Dementia Complex↗
PubMed1996

The spectrum of MRI findings in CNS cryptococcosis in AIDS.

We retrospectively reviewed the cranial MRI appearances of 25 patients with AIDS and microbiologically proven central nervous system (CNS) cryptococcosis. Four patients had a normal scan. Ten patients had dilated perivascular Virchow-Robin spaces that were hyperintense on T2-weighted images. Nine of these patients developed progressive cryptococcomas, eight in the basal ganglia and one in the cerebral white matter. The cryptococcomas displayed high signal on T2-weighted and intermediate to low signal on T1-weighted images. None enhanced after dimeglumine gadopentetate. No abnormal dural or leptomeningeal enhancement was detected in any patient. One patient developed an acquired arachnoid cyst during treatment of CNS cryptococcosis which was thought to represent a focal collection of organisms and mucoid material within the subarachnoid space. In addition either cerebral atrophy and/or background white matter hyperintensity on T2-weighted images was present in 19/25 patients. In two patients the neuropathological findings at autopsy correlated well with the imaging abnormalities. In conclusion, this spectrum of MRI appearances in CNS cryptococcosis reflects the pathological mechanism of invasion by the fungus, but a normal scan or one with features of CNS HIV infection such as atrophy or white matter hyperintensity does not exclude the diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed1996

Sub-cortical white-grey matter contrast on MRI as a quantitative marker of diffuse HIV-related parenchymal abnormality.

White matter change occurs in human immunodeficiency virus (HIV) encephalopathy, which may be difficult to assess subjectively especially in the early stages of disease. This study applies a quantitative approach to the assessment of this finding. Sixty-three HIV seropositive subjects, 47 seronegative blood donors and 17 seronegative homosexual men underwent axial T2 weighted MRI of the brain at 1.5T. Quantitative analysis was performed by obtaining the pixel contrast between parieto-occipital white matter and head of caudate grey matter (Cwg). Highest values of Cwg were found in a subgroup of subjects with AIDS who had diffuse/patchy white matter abnormalities and atrophy on qualitative image assessment. Statistically significant differences were found in Cwg between subjects with high (> or = 200 x 10(6)/I) and low (< 200 x 10(6)/I) CD4 lymphocyte counts (P < 0.05) and between subjects with and without HIV-1 associated cognitive/motor complex (P < 0.05). This technique provides an objective measure of diffuse HIV-related parenchymal abnormality seen on T2 weighted MRI.

AIDS Dementia Complex↗
PubMed1996

Cranial MR imaging in Wilson's disease.

OBJECTIVE: The purpose of the study was to describe the range of abnormalities seen on cranial MR images of patients with Wilson's disease and correlate the findings with clinical severity, duration of disease, and duration of neurologic signs and symptoms before treatment. In those patients with serial studies, the changes on MR images were compared with the clinical response. SUBJECTS AND METHODS: Twenty-five patients with Wilson's disease underwent MR imaging of the brain using conventional spin-echo sequences (n = 25), phase maps (n = 8), and partially refocused interleaved multiple-echo sequences (n = 5). RESULTS: MR imaging findings were abnormal in 22 patients and normal in three patients. The basal ganglia were interpreted as abnormal in 19 (86%) of 22 patients, involving the putamen in 19 (86%), the thalami in 12 (54%), the caudate head in 10 (45%), and the globus pallidus in nine (41%). We found a predilection for involvement of the outer rim of the putamen and the ventral nuclear mass of the thalami. The claustrum was abnormal in three patients. The midbrain was abnormal in 17 (77%) of these 22 patients, affecting predominantly the tegmentum but also the substantia nigra, red nuclei, inferior tectum, and crura. The pons was abnormal in 18 (82%) of 22 patients, and the cerebellum was abnormal in 11 patients (50%), with involvement of the superior and middle cerebellar peduncles. Atrophy was present in 18 (82%) of 22 patients, and cortical white matter changes were apparent in 13 (59%) of 22 patients. The scan of one untreated patient revealed shortening of the T1 relaxation time in the thalami, which was consistent with the paramagnetic effects of copper. Phase maps and partially refocused interleaved multiple-echo sequences performed in eight and five patients, respectively, and used to reveal a susceptibility change induced by iron or copper showed normal findings. We found a significant inverse relationship between severity, but not extent, of change in signal intensity and the length of untreated disease (p = .030) and the total duration of disease (p = .015). The study group was too small to show a correlation with clinical findings. Changes seen on MR images matched the clinical response to treatment in only two of the seven patients who underwent follow-up studies. CONCLUSION: MR imaging revealed abnormalities in the basal ganglia, cerebral white matter, midbrain, pons, and cerebellum. The paramagnetic effects of copper were detected only in untreated patients. Patients with a longer duration of disease had less severe changes in signal intensity. MR imaging was of limited value in follow-up.

Adolescent↗
PubMed1995

Toxoplasmosis and primary central nervous system lymphoma in HIV infection: diagnosis with MR spectroscopy.

PURPOSE: To differentiate intracranial lymphoma from Toxoplasma gondii lesions in patients infected with the human immunodeficiency virus, by means of localized spin-echo proton magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS: Twenty-seven lesions were studied (18 T gondii lesions, nine lymphoma lesions) at 1.5 T. Spectra were acquired at an echo time of 135 msec from voxels centered on the lesions. Both visual analysis and spectral fitting were used to obtain metabolite ratios for choline (Cho), creatine (Cr), N-acetyl (NA), lactate, and lipids. RESULTS: Three spectral categories were seen. One had large lipid peaks with suppression of other metabolites. Another had an elevated Cho/Cr ratio with relatively diminished NA. The third had features of the other two. Examples of each spectrum type were acquired from both T gondii and lymphoma lesions. Neither method of analysis allowed differentiation between lesion types. MR spectroscopy showed an overlap of spectra. CONCLUSION: The authors conclude that toxoplasmosis and lymphoma cannot be differentiated with spin-echo proton MR spectroscopy at 135 msec.

AIDS-Related Opportunistic Infections↗
PubMed1994

Cerebrospinal fluid-intracranial volume ratio measurements in patients with HIV infection: CLASS image analysis technique.

PURPOSE: To prospectively study the cerebrospinal fluid volume-total intracranial volume ratio (CSF/ICV) in human immunodeficiency virus (HIV)-infected patients at various stages of disease. MATERIALS AND METHODS: A total of 258 volume measurements were obtained with use of a 1.5-T magnetic resonance (MR) imager and the cluster localized automated spherical segmentation technique (which reduces two-dimensional pixel data from dual spin-echo MR images to a one-dimensional histogram) in 69 control subjects and 189 HIV-infected patients. RESULTS: The CSF/ICV was statistically significantly increased in patients with late-stage (Centers for Disease Control and Prevention group IV) acquired immunodeficiency syndrome (AIDS) (0.16 +/- 0.05 [standard deviation]) compared with seronegative control subjects (0.12 +/- 0.03) and patients without symptoms (0.13 +/- 0.03). CONCLUSION: No substantial change in CSF/ICV occurs until development of late-stage AIDS.

Acquired Immunodeficiency Syndrome↗