Búsqueda de Substitutos Para Estudios de Neuroimagen con Propósitos de Investigación: Experiencia del Proyecto Atahualpa

Diagnosis of many non-communicable neurological diseases require the use of MRI, which is not readily available in remote rural populations. Efforts should be directed to find portable screening diagnostic tools that may help identify candidates for MRI screening. In the Atahualpa Project, all participants aged.60 years have been invited for the practice of MRI, and about 80% of them have underwent the procedure. Therefore, we have the unique opportunity to test the accuracy of non-invasive exams to be used as surrogates to MRI for identifying candidates for the practice of this exam. To date, we have assessed the value of the ankle-brachial index (ABI), the reliability of the neutrophil-to-lymphocyte ratio (NLR), the accuracy of hypertensive retinopathy, and the value of transcranial Doppler (TCD) to detect individuals with cerebral small vessel disease. Individuals with an abnormal ABI have 4 times de odds of having a silent lacunar infarct than those with a normal ABI. A high NLR has a poor sensitivity but is highly specific for detecting persons with at least one imaging signature of small vessel disease. Individuals with hypertensive retinopathy Grades 2-3 are almost four times more likely to have moderate-to-severe white matter hyperintensities than those with no-or only Grade 1 retinopathy. Finally, the correlation between the pulsatility indexes of major cerebral arteries with imaging markers of small vessel disease, as assessed by TCD, was poor. We are still in the search of some non-expensive and readily available biomarker that allow the identification of apparently healthy persons at risk of suffering a catastrophic cerebrovascular event.