Objective:To investigate the optimal delay time in the quantitative assessment of myocardial fibrosis based on dual-energy CT extracellular volume fraction (DECT-ECV), using MRI as a reference.Methods:Thirty patients with confirmed or suspected of cardiomyopathy were prospectively enrolled in this study. All the patients underwent both cardiac DECT and MRI examination within one week. According to the imaging features of late gadolinium enhancement (LGE) on MRI, myocardial segments were classified into 3 types: ischemic LGE segments, non-ischemic LGE segments and negative LGE segments. According to the DECT delay time, the whole and segmental myocardium were divided into 3 groups: delay of 3 min (Group A), delay of 5 min (Group B) and delay of 7 min (Group C). Correlation and agreement between CT-ECV and MRI-ECV were performed on a basis of overall myocardium and segmental myocardium. Pearson or Spearman test was used for correlation analysis and Bland-Altman test was used for consistency analysis.Results:Thirty patients with 480 segments were finally included in our study. In the analysis based on overall myocardium, MRI-ECV was 33.12%±4.29%, and CT-ECV were 35.81%±4.48%, 36.02%±4.56%, and 36.58%±4.69% in Group A, B, and C, respectively. The agreement between DECT-ECV and MRI-ECV results was good, with the correlation coefficients of 0.878 (group A), 0.955 (Group B) and 0.947 (Group C) (all P<0.001). In the analysis based on segmental myocardium, as for the ischemic LGE myocardial segments, MRI-ECV was 34.60%(31.70%,39.40%), and CT-ECV were 37.50 (34.20, 41.90), 38.20%(36.20%, 40.60%)and 39.40%(35.50%,42.40%)in Group A, B, and C, respectively. The agreement between DECT-ECV and MRI-ECV results was good, with the correlation coefficients of 0.559, 0.695 and 0.682 (all P<0.001) for groups A, B and C, and as for non-ischemic LGE myocardial segments, MRI-ECV was 35.10% (32.68%, 38.70%), and CT-ECV were 38.15% (35.13%, 41.75%), 39.25% (35.78%, 42.20%) and 39.60% (35.88%,42.90%) in Group A, B, and C. The correlation coefficients of CMR-ECV and DECT-ECV of groups A, B and C were 0.531, 0.772 and 0.744 (all P<0.001), showing good agreement; as for negative LGE myocardial segments, MRI-ECV and CT-ECV of Group A, Group B, Group C were 28.50%(27.00%, 30.10%), 31.10%(28.70%, 34.60%), 31.30%(28.40%, 33.80%), 31.30%(29.20%, 34.80%). The correlation coefficients between MRI-ECV and DECT-ECV of group A, B and C were 0.273, 0.508 and 0.425 (all P<0.001), which also showed good agreement. Conclusions:DECT-ECV can be used for quantitative evaluation of myocardial histological features. DECT-ECV with a 5 min and 7 min delay shows good correlation and agreement with MRI-ECV. In order to make this technology more well-known and improve its application capability, our recommendation for clinical practice is a 5 min delay after contrast administration in clinical practice.

The amygdala is an important hub for regulating emotions and is involved in the pathophysiology of many mental diseases, such as depression and anxiety. Meanwhile, the endocannabinoid system plays a crucial role in regulating emotions and mainly functions through the cannabinoid type-1 receptor (CB₁R), which is strongly expressed in the amygdala of non-human primates (NHPs). However, it remains largely unknown how the CB₁Rs in the amygdala of NHPs regulate mental diseases. Here, we investigated the role of CB₁R by knocking down the cannabinoid receptor 1 (CNR1) gene encoding CB₁R in the amygdala of adult marmosets through regional delivery of AAV-SaCas9-gRNA. We found that CB₁R knockdown in the amygdala induced anxiety-like behaviors, including disrupted night sleep, agitated psychomotor activity in new environments, and reduced social desire. Moreover, marmosets with CB₁R-knockdown had up-regulated plasma cortisol levels. These results indicate that the knockdown of CB₁Rs in the amygdala induces anxiety-like behaviors in marmosets, and this may be the mechanism underlying the regulation of anxiety by CB₁Rs in the amygdala of NHPs.
Animals ; Callithrix ; Receptors, Cannabinoid ; Anxiety ; Amygdala ; Cannabinoids ; Phenotype