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Conventional MRI has helped characterize the variety of neuropsychiatric systemic lupus erythematosus symptoms, including atrophy, focal or diffuse nonspecific white matter lesions, hemorrhage, infarcts, and demyelination. However, conventional MRI may be negative or nonspecific, even in symptomatic patients.

MR spectroscopy has found protein ratios that may represent inflammatory processes, demyelination, or cell membrane degradation, all of which involve microstructural changes that affect how water molecules move—the diffusivity.

Diffusion-weighted imaging (DWI), an MR-based technique, is sensitive to water's motion within extracellular space. DWI can diagnose and characterize abnormalities in brain tissue.

Diffusion tensor imaging (DTI) analyzes the directional diffusion properties of water and the integrity of organized tissue microstructures. It is often applied to white matter tracts to reveal tissue orientation and integrity.

Tractography lets researchers see the symmetry of brain water diffusion. Bundles of fiber tracts make the water diffuse asymmetrically in the major axis parallel to the direction of the fibers. The asymmetry is called anisotropy. A direct relationship exists between the number of fibers and the degree of anisotropy.

Aziz M. Ulug, Ph.D., of Cornell University, Ithaca, N. Y., and colleagues used these techniques to study 34 SLE patients and 29 age-matched controls. Participants underwent MRI (1.5 T), DWI, DTI, and tractography (Magn. Reson. Imaging 2007;25:399–405). Overall, 20 patients had an abnormal MRI finding: 3 showed volume loss inappropriate for age; 15 had focal or spreading nonspecific white matter disease; and 2 showed both volume loss and nonspecific white matter disease.

The Dav is average diffusion constant for all MRI pixels. The greater Dav, the more freely water diffuses. In SLE, there were regions where Dav was higher, versus controls. In the entire SLE group, Dav was higher in the anterior internal capsule, frontal lobe, and splenium of corpus callosum.

BDav is the diffusion constant (Dav) measured from the entire brain. BDav is is useful for diseases in which the insult is not focal or not exactly known. “In SLE patients, we find BDav is increased compared to normals,” said Dr. Ulug. “The disease [is] affecting a large portion of the brain (or entire brain). The BDav value was increased in the patient group that [had] normal MRI findings, compared with controls. This means the BDav measure is a very sensitive one that detects the disease or disease load in the brain before regular MRI.”

Diffusion anisotropy in the anterior internal capsule was significantly decreased in the patient group, suggesting a preclinical impairment of axon integrity (contained in the anterior internal capsule and running to and from the frontal association cortex). Anisotropy in the anterior internal capsule for patients with normal MRI findings was lower than in patients with abnormal MRI findings. This suggests ractional anisotropy is a sensitive tool to detect early signs of disease involvement. Tractography in SLE patients showed fewer trackable fibers in the whole brain compared with controls, suggesting white matter damage, said Dr. Ulug.

Patients with SLE (left) have fewer trackable white matter fibers within the whole brain, compared with healthy controls (right), on DTI tractography. Images courtesy Aziz M. Ulug, Ph.D.

Conventional MRI has helped characterize the variety of neuropsychiatric systemic lupus erythematosus symptoms, including atrophy, focal or diffuse nonspecific white matter lesions, hemorrhage, infarcts, and demyelination. However, conventional MRI may be negative or nonspecific, even in symptomatic patients.

MR spectroscopy has found protein ratios that may represent inflammatory processes, demyelination, or cell membrane degradation, all of which involve microstructural changes that affect how water molecules move—the diffusivity.

Diffusion-weighted imaging (DWI), an MR-based technique, is sensitive to water's motion within extracellular space. DWI can diagnose and characterize abnormalities in brain tissue.

Diffusion tensor imaging (DTI) analyzes the directional diffusion properties of water and the integrity of organized tissue microstructures. It is often applied to white matter tracts to reveal tissue orientation and integrity.

Tractography lets researchers see the symmetry of brain water diffusion. Bundles of fiber tracts make the water diffuse asymmetrically in the major axis parallel to the direction of the fibers. The asymmetry is called anisotropy. A direct relationship exists between the number of fibers and the degree of anisotropy.

Aziz M. Ulug, Ph.D., of Cornell University, Ithaca, N. Y., and colleagues used these techniques to study 34 SLE patients and 29 age-matched controls. Participants underwent MRI (1.5 T), DWI, DTI, and tractography (Magn. Reson. Imaging 2007;25:399–405). Overall, 20 patients had an abnormal MRI finding: 3 showed volume loss inappropriate for age; 15 had focal or spreading nonspecific white matter disease; and 2 showed both volume loss and nonspecific white matter disease.

The Dav is average diffusion constant for all MRI pixels. The greater Dav, the more freely water diffuses. In SLE, there were regions where Dav was higher, versus controls. In the entire SLE group, Dav was higher in the anterior internal capsule, frontal lobe, and splenium of corpus callosum.

BDav is the diffusion constant (Dav) measured from the entire brain. BDav is is useful for diseases in which the insult is not focal or not exactly known. “In SLE patients, we find BDav is increased compared to normals,” said Dr. Ulug. “The disease [is] affecting a large portion of the brain (or entire brain). The BDav value was increased in the patient group that [had] normal MRI findings, compared with controls. This means the BDav measure is a very sensitive one that detects the disease or disease load in the brain before regular MRI.”

Diffusion anisotropy in the anterior internal capsule was significantly decreased in the patient group, suggesting a preclinical impairment of axon integrity (contained in the anterior internal capsule and running to and from the frontal association cortex). Anisotropy in the anterior internal capsule for patients with normal MRI findings was lower than in patients with abnormal MRI findings. This suggests ractional anisotropy is a sensitive tool to detect early signs of disease involvement. Tractography in SLE patients showed fewer trackable fibers in the whole brain compared with controls, suggesting white matter damage, said Dr. Ulug.

Patients with SLE (left) have fewer trackable white matter fibers within the whole brain, compared with healthy controls (right), on DTI tractography. Images courtesy Aziz M. Ulug, Ph.D.

Conventional MRI has helped characterize the variety of neuropsychiatric systemic lupus erythematosus symptoms, including atrophy, focal or diffuse nonspecific white matter lesions, hemorrhage, infarcts, and demyelination. However, conventional MRI may be negative or nonspecific, even in symptomatic patients.

MR spectroscopy has found protein ratios that may represent inflammatory processes, demyelination, or cell membrane degradation, all of which involve microstructural changes that affect how water molecules move—the diffusivity.

Diffusion-weighted imaging (DWI), an MR-based technique, is sensitive to water's motion within extracellular space. DWI can diagnose and characterize abnormalities in brain tissue.

Diffusion tensor imaging (DTI) analyzes the directional diffusion properties of water and the integrity of organized tissue microstructures. It is often applied to white matter tracts to reveal tissue orientation and integrity.

Tractography lets researchers see the symmetry of brain water diffusion. Bundles of fiber tracts make the water diffuse asymmetrically in the major axis parallel to the direction of the fibers. The asymmetry is called anisotropy. A direct relationship exists between the number of fibers and the degree of anisotropy.

Aziz M. Ulug, Ph.D., of Cornell University, Ithaca, N. Y., and colleagues used these techniques to study 34 SLE patients and 29 age-matched controls. Participants underwent MRI (1.5 T), DWI, DTI, and tractography (Magn. Reson. Imaging 2007;25:399–405). Overall, 20 patients had an abnormal MRI finding: 3 showed volume loss inappropriate for age; 15 had focal or spreading nonspecific white matter disease; and 2 showed both volume loss and nonspecific white matter disease.

The Dav is average diffusion constant for all MRI pixels. The greater Dav, the more freely water diffuses. In SLE, there were regions where Dav was higher, versus controls. In the entire SLE group, Dav was higher in the anterior internal capsule, frontal lobe, and splenium of corpus callosum.

BDav is the diffusion constant (Dav) measured from the entire brain. BDav is is useful for diseases in which the insult is not focal or not exactly known. “In SLE patients, we find BDav is increased compared to normals,” said Dr. Ulug. “The disease [is] affecting a large portion of the brain (or entire brain). The BDav value was increased in the patient group that [had] normal MRI findings, compared with controls. This means the BDav measure is a very sensitive one that detects the disease or disease load in the brain before regular MRI.”

Diffusion anisotropy in the anterior internal capsule was significantly decreased in the patient group, suggesting a preclinical impairment of axon integrity (contained in the anterior internal capsule and running to and from the frontal association cortex). Anisotropy in the anterior internal capsule for patients with normal MRI findings was lower than in patients with abnormal MRI findings. This suggests ractional anisotropy is a sensitive tool to detect early signs of disease involvement. Tractography in SLE patients showed fewer trackable fibers in the whole brain compared with controls, suggesting white matter damage, said Dr. Ulug.

Patients with SLE (left) have fewer trackable white matter fibers within the whole brain, compared with healthy controls (right), on DTI tractography. Images courtesy Aziz M. Ulug, Ph.D.