title: A method of correcting for linear drift in computed tomography brain scans.
abstract: Linear drift of X-ray attenuation coefficients must be corrected if quantitative comparisons are to be made between computed tomography (CT) brain scans of the same individual performed at different times. Such a correction is accomplished by comparing the low (cerebrospinal fluid) end of the attenuation coefficient frequency histograms using a percentile--percentile plot. A "drift correction" permits serial quantitative assessments of the progression or regression of white matter hypodensity, such as occurs in drug induced leukoencephalopathy.
mesh_terms: D000293:Adolescent; D001921:Brain / Q000000981:diagnostic imaging*; D001927:Brain Diseases / Q000139:chemically induced / Q000000981:diagnostic imaging; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging; D014695:Cerebral Ventriculography; D002555:Cerebrospinal Fluid; D004582:Electronics, Medical; D005910:Glioma / Q000000981:diagnostic imaging; D006801:Humans; D008727:Methotrexate / Q000009:adverse effects; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D008727:Methotrexate