Clinical-radiological approach to nontraumatic myelopathy. / Enfoque clínico-radiológico de la mielopatía no traumática.

Diseases of the spinal cord often have devastating consequences and imaging studies are indispensable for their diagnosis. The fundamental imaging technique to evaluate these diseases is magnetic resonance imaging of the spine. The diagnostic approach must be based on the clinical context, the time elapsed since the onset of symptoms and signs, and the imaging findings; for this reason, it sometimes necessary to broaden the study to include the brain. The first step in the diagnostic algorithm is to rule out spinal cord compression before evaluating other causes of myelopathy, which sometimes has multiple causes. This paper includes a broad review of the different diseases that can cause myelopathy, their imaging manifestations, their differential diagnoses, and diagnostic algorithms. Using an appropriate radiological approach will result in better management and prognosis of these patients.

[Brain apparent diffusion coefficient: differences caused by age, sex, laterality, and distinct b value]. / Coeficiente de difusión aparente cerebral: diferencias por edad, sexo, lateralidad y diferente valor b.

OBJECTIVE: To analyze the effects of age, sex, and b value on the apparent diffusion coefficient (ADC) in brain areas affected by neurodegenerative diseases. MATERIAL AND METHODS: We studied the ADC of the genu and splenium of the corpus callosum and of the hippocampus in normal patients using diffusion magnetic resonance imaging (dMRI) with b1,000 s/mm2 and b3,000 s/mm2. We calculated the differences between the ADC (diffusion differential [DD]) with b1,000 and with b3,000 for each region. Patients were classified into the following age groups (60 years old). We used a Kruskal-Wallis one-way ANOVA and the Bonferroni correction to analyze the differences in ADC and DD between age groups and between sexes. Pearson's chi-square test was used to correlate the ADC and DD with age. RESULTS: In the right hippocampus, we observed differences in ADC (b1,000, p=0.011; b3,000, p=0.024) and DD (p=0.006) with age. Differences in ADC were observed between the 31-60 year-old age group and the >60 year-old age group (p=0.009) for b1,000, and between the<30 year-old age group and the 31-60 year-old age group (p=0.036) for b3,000. The DD in the >60 year-old age group was different from the rest. In the corpus callosum, there were significant differences between sexes in the DD of the genu (p=0.016). The DD was correlated with age in the right hippocampus (r=0.321, p=0.023). CONCLUSIONS: Our data indicate greater stability in mean ADC values with b3000 during aging. It might be useful to analyze the ADC with a higher b in patients with neurodegenerative diseases.