A systemic review of rubidium-82 PET contrasted with 99mTc-MIBI SPECT for imaging coronary artery disease

BACKGROUND

99mTc-sestamibi single photon emission tomography (SPECT) method is widely used for imaging coronary artery disease (CAD). 82-Rubidium-PET is an alternative method that can be used to perform the same purpose.

PURPOSE/AIM

This study aims to determine whether 82-Rubidium-PET can offer extra value over 99mTc-sestamibi SPECT in imaging CAD.

METHODS

To achieve the study aim, a systematic review of the literature for the 2 tracers were conducted. The aim of the systemic review was to find every related previous study that corresponded to well-defined scientific criteria. The analysis of the results was restricted to peer-reviewed papers in order to avoid any selective outcome reports. Besides, extra analysis was carried out to curb or avoid any ascertainment bias. The qualified studies selected for this research were then assessed for the risk of bias. Furthermore, the details of the methods were rechecked to ensure that they were comparable, before synthesizing the results.

RESULTS

Eighteen original studies were selected and included in the final analysis out of 803 articles identified at the initial research. Overall, the mean value of sensitivity and specificity for diagnosis of CAD was 84.3% and 75.4%, respectively for technetium 99m sestamibi (99mTc-MIBI). On the other hand, for 82-Rubidium-PET, the mean value of sensitivity and specificity for diagnosis of CAD was 81% and 81%, respectively. The accuracy of diagnostics of these imaging modalities was dependent on the radiotracers and stress agent used in these studies, with 99mTc-MIBI achieving the highest diagnostic value.

CONCLUSION

This study concludes that 99mTc-MIBI-SPECT has higher diagnostic value for diagnosing CAD compared to 82-Rubidium-PET. This indicates that 99mTc-MIBI-SPECT is a more valuable technique for predicting CAD. Besides, for the stress agents used to stimulate the heart and increase workload, this research/study recommends the use of adenosine for the SPECT and the use of dipyridamole for positron emission tomography. However, it suggests the need for more systemic and theoretical studies to assess the real value of 82-Rubidium-PET and the value of stress agents.

Amygdala and subregion volumes are associated with photoperiod and seasonal depressive symptoms: A cross-sectional study in the UK Biobank cohort

Although seasonal changes in amygdala volume have been demonstrated in animals, seasonal differences in human amygdala subregion volumes have yet to be investigated. Amygdala volume has also been linked to depressed mood. Therefore, we hypothesised that differences in photoperiod would predict differences in amygdala or subregion volumes and that this association would be linked to depressed mood. 10,033 participants ranging in age from 45 to 79 years were scanned by MRI in a single location. Amygdala subregion volumes were obtained using automated processing and segmentation algorithms. A mediation analysis tested whether amygdala volume mediated the relationship between photoperiod and mood. Photoperiod was positively associated with total amygdala volume (p < .001). Multivariate (GLM) analyses revealed significant effects of photoperiod across all amygdala subregion volumes for both hemispheres (p < .001). Post hoc univariate regression analyses revealed significant associations of photoperiod with each amygdala subregion volume (p < .001). PLS showed the highest loadings of amygdala subregions in lateral nucleus, ABN, basal nucleus, CAT, PLN, AAA, central nucleus, cortical nucleus and medial nucleus for left hemisphere and ABN, lateral nucleus, CAT, PLN, cortical nucleus, AAA, central nucleus and medial nucleus for right hemisphere. There were no significant associations between photoperiod and mood nor between mood scores and amygdala volumes, and due to the lack of these associations, the mediation hypothesis was not supported. This study is the first to demonstrate an association between photoperiod and amygdala volume. These findings add to the evidence supporting the role of photoperiod on brain structural plasticity.