Background
In patients with suspected coronary artery disease (CAD), myocardial perfusion is assessed under rest and pharmacological stress to identify ischemia. Splenic switch‐off, defined as the stress to rest splenic perfusion attenuation in response to adenosine, has been proposed as an indicator of stress adequacy. Its occurrence has been previously assessed in first‐pass perfusion images, but the use of noncontrast techniques would be highly beneficial.
Purpose
To explore the ability of pseudo‐continuous arterial spin labeling (PCASL) to identify splenic switch‐off in patients with suspected CAD.
Study Type
Prospective.
Population
Five healthy volunteers (age 24.8 ± 3.8 years) and 32 patients (age 66.4 ± 8.2 years) with suspected CAD.
Field strength/Sequence
A 1.5‐T/PCASL (spin‐echo) and first‐pass imaging (gradient‐echo).
Assessment
In healthy subjects, multi‐delay PCASL data (500–2000 msec) were acquired to quantify splenic blood flow (SBF) and determine the adequate postlabeling delay (PLD) for single‐delay acquisitions (PLD > arterial transit time). In patients, single‐delay PCASL (1200 msec) and first‐pass perfusion images were acquired under rest and adenosine conditions. PCASL data were used to compute SBF maps and SBF stress‐to‐rest ratios. Three observers classified patients into “switch‐off” and “failed switch‐off” groups by visually comparing rest‐stress perfusion data acquired with PCASL and first‐pass, independently. First‐pass categories were used as reference to evaluate the accuracy of quantitative classification.
Statistical Tests
Wilcoxon signed‐rank, Pearson correlation, kappa, percentage agreement, Generalized Linear Mixed Model, Mann–Whitney, Pearson Chi‐squared, receiver operating characteristic, area‐under‐the‐curve (AUC) and confusion matrix. Significance: P value < 0.05.
Results
A total of 27 patients (84.4%) experienced splenic switch‐off according to first‐pass categories. Comparison of PCASL‐derived SBF maps during stress and rest allowed assessment of splenic switch‐off, reflected in a reduction of SBF values during stress. SBF stress‐to‐rest ratios showed a 97% accuracy (sensitivity = 80%, specificity = 100%, AUC = 85.2%).
Data Conclusion
This study could demonstrate the feasibility of PCASL to identify splenic switch‐off during adenosine perfusion MRI, both by qualitative and quantitative assessments.
Evidence Level
2
Technical Efficacy
2
The Diet, Physical Activity and Health (Alimentación, Actividad física y Salud, ALAS) program is an intervention implemented by the municipal health services of Madrid with the objective of reducing weight and preventing diabetes in high-risk population by improving diet and physical activity. The ALAS program combines individual visits with a 10-session group workshop that takes place over a 6-month period. This study evaluated the effectiveness of the ALAS intervention implemented under real-life conditions between 2016 and 2019. The intervention was evaluated with a pre- and post-intervention study with follow-up performed 6 and 12 months from the start of the program. The analyzed outcomes were a 5–10% reduction in the initial weight, body mass index (BMI), waist circumference and a change in glycemic status in prediabetic participants. Statistical models were adjusted by sociodemographic variables. The participants were recruited from municipal community health centers or referred by municipal occupational health services. Between 2016 and 2019, 1629 people participated in the program. At 6 months, 85% of the participants had lost weight; 43% had lost 5% or more of their initial weight, and 12% had lost 10% or more. Regarding BMI, 22.3% of participants who were initially obese were no longer obese, and 15.2% of the overweight participants achieved normal weight. A total of 35.1% of the prediabetic participants reverted to normoglycemic status. The intervention was found to be more effective for men, for those who completed the intervention and those who accessed the program through the occupational health route. Among the participants who accessed the intervention via the community, the intervention was more effective in those with a high educational level. The evaluation demonstrated the effectiveness of the ALAS program for reducing weight and the risk of developing Type 2 diabetes when applied under real-life conditions. The effectiveness of the intervention differed according to gender, access route and educational level of the participants.
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