Changes in quantitative magnetic resonance imaging susceptibility mapping in Alzheimer's disease

Objective : to investigate changes in quantitative susceptibility mapping (QSM) of magnetic resonance imaging (MRI) of the brain in patients with Alzheimer's disease (AD) and to compare the results with those of a morphometric study and the state of cognitive functions. Material and methods. The study included 11 patients with AD (five women and six men; mean age 75.3±9.4 years; MoCA score 11.2±3.9) and 12 volunteers without cognitive impairment (eight women and four men; mean age 72.7±8.9 years; MoCA score 26.7±0.9). QSM MRI was performed on a Signa PET/MR 3.0 T tomograph using a 32-channel coil. In both hemispheres, the regions studied included the amygdala, caudate nucleus, putamen, hippocampus, globus pallidus, thalamus, frontal, temporal, parietal and occipital lobes, and posterior cingulate gyrus. For each region, volume (voxels), QSM (ppm), and QSM/volume ratio were calculated. Results . In patients with AD, QSM and QSM/volume values were higher and volume was lower than in the control group in most areas. The left temporal lobe cortex (volume, QSM and QSM/volume – SE ≥93.7, SP ≥90.4, AUC ≥0.921; p<0.0001), the hippocampus (volume and QSM/volume – SE ≥91.9, SP ≥89.1, AUC ≥0.939; p<0.0001) and the amygdala (volume – SE ≥88.4, SP ≥91.6, AUC ≥0.902; p<0.0001) of both hemispheres had the highest sensitivity and specificity. In the hippocampi and amygdalae, the QSM/volume ratio had greater sensitivity and specificity than QSM (ΔAUC ≥0.277±0.105, z≥2.636; p≤0.0084). There was a correlation between the total MoCA score and the volume of the amygdala, hippocampus, and temporal lobe cortex of the left hemisphere (r≥0.429; p≤0.0026). In addition, there was a relationship between the total MoCA score and QSM in the caudate nuclei and putamen of both hemispheres, in the left temporal lobe (r≥-0.429; p≤0.019) and QSM/volume in the caudate nuclei and hippocampi of both hemispheres, in the putamen and temporal lobe of the left hemisphere (r≥-0.415; p≤0.014). Conclusion . This study demonstrated a correlation between QSM, the QSM/volume ratio, morphometric parameters, and the total MoCA score in AD. The QSM/volume ratio has greater sensitivity and specificity than QSM in distinguishing between the AD group and the control group.