The Neuroradiology Journal 19: 597-602, 2006
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Proton Magnetic Resonance Spectroscopy in Patients with Normal Pressure Hydrocephalus B. KUBAS, W. KUŁAK, W. SOBANIEC, J. WALECKI, J. LEWKO Department Radiology, Institution Medical University; Bialystok, Poland
Key words: proton spectroscopy magnetic resonance, white matter, normal pressure hydrocephalus
SUMMARY – The objective of this prospective study was the application of proton magnetic resonance spectroscopy (1HMRS) in patients with normal pressure hydrocephalus (NPH) to determine the metabolite profile in the white matter next to left lateral ventricle and to assess the relationship of this profile with Evan’s index. The study included 26 patients with NPH. Diagnosis of NPH was confirmed by clinical symptoms such as gait disturbance, dementia or urinary incontinence and CT study with ventricular enlargement. Ratios of NAA/Cr, Cho/Cr, Lac/Cr and mI/Cr from deep white matter were measured and compared with Evan’s index and diameter of the IIIrd ventricle. Patients with hydrocephalus showed decreased ratios of N-acetylaspartate (NAA)/Cr (creatine), and increased ratios of Lac(lactate)/Cr in the white matter near the left frontal horn of the lateral ventricle compared with a well-matched control group. There was no correlation between NAA/Cr, Ch/Cr, Lac/Cr, mI (myo-Inositol)/Cr and Evan’s index. A significant correlation was found between Lac/Cr and third ventricle diameter. A positive correlation was noted between Cho/Cr and dementia in patients with NPH. Our preliminary results of 1 H MRS support the idea that NPH is associated with white matter ischemia. Proton MRS is a very useful tool for evaluating major changes in metabolic levels in deep white matter in NPH patients.
Introduction Normal pressure hydrocephalus (NPH) is treatable 1. The diagnosis is usually established on the basis of an improvement in symptoms after shunting of CSF 2,3. The clinical symptoms of NPH are characterized by mild memory impairment and apathy, ataxic gait and incontinence 4. Gait deficits are commonly seen in NPH, but mental deterioration may be subtle or even unrecognized. Incontinence appears most often after the appearance of gait disturbance and memory impairment. Several studies have measured cerebral blood flow (CBF) with single-photon emission CT (SPECT) and xenon CT imaging disclosing reduced CBF in patients with NPH 5,6. Decreased regional cerebral metabolism has also been observed on positron emission tomography (PET) with 18F-2-fluorodeoxyglucose 7. Many patients with NPH do not present with the classic clinical or neuroimaging patterns, and it remains a clinical challenge to detect the metabolite changes in these
patients. Proton magnetic resonance spectroscopy (1H MRS) is widely applied in the determination and differentiation of brain tumors, hypoxia, post radiotherapy changes and other lesions mimicking neoplasm-like abscesses 8,9,10,11,12,13 . NAA is a neuronal marker, the other metabolites can be viewed as cerebral indicators of energy metabolism- creatine (Cr) and of cytoplasmic and mitochondrial redox state-lactates (Lac) and glutamines (Glx). Myo-Inositol (mI) is a precursor for the phosphatidylinositol second messenger system and regulates osmotic processes within the brain; it also takes part in mood states. Elevated mI level may reflect demyelination and glial proliferation. The decrease in NAA/Cr ratio may indicate neuroaxonal damage or deficient neuronal formation 13,14. The increased Cho/Cr and mI/Cr levels, which could indicate increased membrane turnover, and myelin breakdown and astrocytosis respectively, might correspond to glial cell proliferation. 597
Proton Magnetic Resonance Spectroscopy in Patients with Normal Pressure Hydrocephalus
B. Kubas
Figure 1. An axial T2-weighted magnetic resonance image from a patient with normal pressure hydrocephalus. The white rectangle in the left frontal lobe is the voxel of interest.
Figure 2. Proton magnetic resonance spectroscopy spectrum of the same patient. N-acetyl aspartate (NAA) at 2.02 (ppm), creatine (Cr) at 3.03 ppm, choline (Cho) at 3.22 ppm, Lactate (Lac) at 1.22 and myo-inositol (mI) at 3.55 ppm, were obtained. Chemical shifts are indicated in parts per million (ppm).
The objective of this prospective study was the application of 1H-MRS to patients with normal-pressure hydrocephalus: (a) to determine the metabolite profile of patients with hydrocephalus in the white matter next to the frontal horn; and (b) to assess the relationship of this profile with Evan’s index and IIIrd ventricle diameter. The study was approved by the Ethics Committee of the Medical University of Bialystok.
such as gait disturbance, dementia or urinary incontinence and CT study with ventricle enlargement. Patients with brain tumors, psychiatric and metabolic disorders were excluded from the study. 1 HMRS was performed before insertion of the shunt and, in two patients, also after shunting. 33 control subjects (age range 47-75 years, mean age 63 years) with no history of psychiatric or neurologic disorders also participated in this study. MRI and HMRS
Methods The present study included 26 patients with normal pressure hydrocephalus (16 women and 10 men, age range 51-82 years, mean age 65 years), nine of them had dementia. Diagnosis of NPH was confirmed by clinical symptoms 598
All MR scans were obtained using a 1.5 T MR scanner (Picker Eclipse) with the aid of a standard circular polarized head coil. Imaging sequences with T1-weighted FAST scan (TR 300 ms, TE 4.5, 5 mm thick sections) pre and post i.v. contrast medium administration (0.1 mmol/ kg, Megnevist, Schering) were performed. T2-
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The Neuroradiology Journal 19: 597-602, 2006
Table 1 Metabolite ratios in the white matter next to the left frontal horn of the lateral ventricle in patients with normal pressure hydrocephalus and a control group (X ± Standard Deviation)
Metabolites
Hydrocephalus n = 26
Control n = 33
p value
NAA/Cr
1.71 ± 0.25
1.85 ± 0.29
p= 0.043
Cho/Cr
0.78 ± 0.10
0.79 ± 0.12
NS
Lac/Cr
0.19 ± 0.29
0.003 ± 0.14
p
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Proton Magnetic Resonance Spectroscopy in Patients with Normal Pressure Hydrocephalus B. KUBAS, W. KUŁAK, W. SOBANIEC, J. WALECKI, J. LEWKO Department Radiology, Institution Medical University; Bialystok, Poland
Key words: proton spectroscopy magnetic resonance, white matter, normal pressure hydrocephalus
SUMMARY – The objective of this prospective study was the application of proton magnetic resonance spectroscopy (1HMRS) in patients with normal pressure hydrocephalus (NPH) to determine the metabolite profile in the white matter next to left lateral ventricle and to assess the relationship of this profile with Evan’s index. The study included 26 patients with NPH. Diagnosis of NPH was confirmed by clinical symptoms such as gait disturbance, dementia or urinary incontinence and CT study with ventricular enlargement. Ratios of NAA/Cr, Cho/Cr, Lac/Cr and mI/Cr from deep white matter were measured and compared with Evan’s index and diameter of the IIIrd ventricle. Patients with hydrocephalus showed decreased ratios of N-acetylaspartate (NAA)/Cr (creatine), and increased ratios of Lac(lactate)/Cr in the white matter near the left frontal horn of the lateral ventricle compared with a well-matched control group. There was no correlation between NAA/Cr, Ch/Cr, Lac/Cr, mI (myo-Inositol)/Cr and Evan’s index. A significant correlation was found between Lac/Cr and third ventricle diameter. A positive correlation was noted between Cho/Cr and dementia in patients with NPH. Our preliminary results of 1 H MRS support the idea that NPH is associated with white matter ischemia. Proton MRS is a very useful tool for evaluating major changes in metabolic levels in deep white matter in NPH patients.
Introduction Normal pressure hydrocephalus (NPH) is treatable 1. The diagnosis is usually established on the basis of an improvement in symptoms after shunting of CSF 2,3. The clinical symptoms of NPH are characterized by mild memory impairment and apathy, ataxic gait and incontinence 4. Gait deficits are commonly seen in NPH, but mental deterioration may be subtle or even unrecognized. Incontinence appears most often after the appearance of gait disturbance and memory impairment. Several studies have measured cerebral blood flow (CBF) with single-photon emission CT (SPECT) and xenon CT imaging disclosing reduced CBF in patients with NPH 5,6. Decreased regional cerebral metabolism has also been observed on positron emission tomography (PET) with 18F-2-fluorodeoxyglucose 7. Many patients with NPH do not present with the classic clinical or neuroimaging patterns, and it remains a clinical challenge to detect the metabolite changes in these
patients. Proton magnetic resonance spectroscopy (1H MRS) is widely applied in the determination and differentiation of brain tumors, hypoxia, post radiotherapy changes and other lesions mimicking neoplasm-like abscesses 8,9,10,11,12,13 . NAA is a neuronal marker, the other metabolites can be viewed as cerebral indicators of energy metabolism- creatine (Cr) and of cytoplasmic and mitochondrial redox state-lactates (Lac) and glutamines (Glx). Myo-Inositol (mI) is a precursor for the phosphatidylinositol second messenger system and regulates osmotic processes within the brain; it also takes part in mood states. Elevated mI level may reflect demyelination and glial proliferation. The decrease in NAA/Cr ratio may indicate neuroaxonal damage or deficient neuronal formation 13,14. The increased Cho/Cr and mI/Cr levels, which could indicate increased membrane turnover, and myelin breakdown and astrocytosis respectively, might correspond to glial cell proliferation. 597
Proton Magnetic Resonance Spectroscopy in Patients with Normal Pressure Hydrocephalus
B. Kubas
Figure 1. An axial T2-weighted magnetic resonance image from a patient with normal pressure hydrocephalus. The white rectangle in the left frontal lobe is the voxel of interest.
Figure 2. Proton magnetic resonance spectroscopy spectrum of the same patient. N-acetyl aspartate (NAA) at 2.02 (ppm), creatine (Cr) at 3.03 ppm, choline (Cho) at 3.22 ppm, Lactate (Lac) at 1.22 and myo-inositol (mI) at 3.55 ppm, were obtained. Chemical shifts are indicated in parts per million (ppm).
The objective of this prospective study was the application of 1H-MRS to patients with normal-pressure hydrocephalus: (a) to determine the metabolite profile of patients with hydrocephalus in the white matter next to the frontal horn; and (b) to assess the relationship of this profile with Evan’s index and IIIrd ventricle diameter. The study was approved by the Ethics Committee of the Medical University of Bialystok.
such as gait disturbance, dementia or urinary incontinence and CT study with ventricle enlargement. Patients with brain tumors, psychiatric and metabolic disorders were excluded from the study. 1 HMRS was performed before insertion of the shunt and, in two patients, also after shunting. 33 control subjects (age range 47-75 years, mean age 63 years) with no history of psychiatric or neurologic disorders also participated in this study. MRI and HMRS
Methods The present study included 26 patients with normal pressure hydrocephalus (16 women and 10 men, age range 51-82 years, mean age 65 years), nine of them had dementia. Diagnosis of NPH was confirmed by clinical symptoms 598
All MR scans were obtained using a 1.5 T MR scanner (Picker Eclipse) with the aid of a standard circular polarized head coil. Imaging sequences with T1-weighted FAST scan (TR 300 ms, TE 4.5, 5 mm thick sections) pre and post i.v. contrast medium administration (0.1 mmol/ kg, Megnevist, Schering) were performed. T2-
www. centauro. it
The Neuroradiology Journal 19: 597-602, 2006
Table 1 Metabolite ratios in the white matter next to the left frontal horn of the lateral ventricle in patients with normal pressure hydrocephalus and a control group (X ± Standard Deviation)
Metabolites
Hydrocephalus n = 26
Control n = 33
p value
NAA/Cr
1.71 ± 0.25
1.85 ± 0.29
p= 0.043
Cho/Cr
0.78 ± 0.10
0.79 ± 0.12
NS
Lac/Cr
0.19 ± 0.29
0.003 ± 0.14
p
