One-tissue compartment model for myocardial perfusion quantification with N-13 ammonia PET provides matching results: A cross-comparison between Carimas, FlowQuant, and PMOD

Purpose To cross-compare three software packages (SPs)-Carimas, FlowQuant, and PMOD-to quantify myocardial perfusion at global, regional, and segmental levels. Materials and Methods Stress N-13 ammonia PET scans of 48 patients with HCM were analyzed in three centers using Carimas, FlowQuant, and PMOD. Values agreed if they had an ICC > 0.75 and a difference < 20% of the median across all observers. Results When using 1TCM on the global level, the agreement was good, and the maximum difference between 1TCM MBF values was 17.2% (ICC = 0.83). On the regional level, the agreement was acceptable except in the LCx region (25.5% difference, ICC = 0.74) between FlowQuant and PMOD. Carimas-1TCM agreed well with PMOD-1TCM and FlowQuant-1TCM. Values obtained with FlowQuant-1TCM had a somewhat lesser agreement with PMOD-1TCM, especially at the segmental level. Conclusions The global and regional MBF values (with one exception) agree well between the different software packages. There is significant variability in segmental values, mainly located in the LCx region and segments. Out of the studied tools, Carimas can be used interchangeably with both PMOD and FlowQuant for 1TCM implementation on all levels-global, regional, and segmental.</p

Myocardial perfusion quantification with Rb-82 PET: good interobserver agreement of Carimas software on global, regional, and segmental levels

PurposeTo estimate the interobserver agreement of the Carimas software package (SP) on global, regional, and segmental levels for the most widely used myocardial perfusion PET tracer-Rb-82.Materials and methodsRest and stress Rb-82 PET scans of 48 patients with suspected or known coronary artery disease (CAD) were analyzed in four centers using the Carimas SP. We considered values to agree if they simultaneously had an intraclass correlation coefficient (ICC) > 0.75 and a difference ResultsThe median values on the segmental level were 1.08 mL/min/g for rest myocardial blood flow (MBF), 2.24 mL/min/g for stress MBF, and 2.17 for myocardial flow reserve (MFR). For the rest MBF and MFR, all the values at all the levels fulfilled were in excellent agreement. For stress MBF, at the global and regional levels, all the 24 comparisons showed excellent agreement. Only 1 out of 102 segmental comparisons (seg. 14) was over the adequate agreement limit-23.5% of the median value (ICC = 0.95).ConclusionInterobserver agreement for Rb-82 PET myocardial perfusion quantification analyzed with Carimas is good at any LV segmentation level-global, regional, and segmental. It is good for all the estimates-rest MBF, stress MBF, and MFR.</p

Экономическая природа феномена «халява» в среде российских студентов

The article is devoted to the problems of behavioral economics in terms of formation of the attitude and perception of goods with zero price in their special form – “freebie” (or in Russian – “haljava”) as a special form of free (or almost free) good. The study showed the relationship between economic and non-economic goods. The definition of “freebie” is given as a situation of receiving a good in which an individual (recipient) bears zero or insignificant (inconspicuous) economic or physical costs with a perceived high assessment of the usefulness of the good. Three situations were considered: the recipient of a good is a consumer, an employee and a special case of employee – a student obtaining grades in the educational process. Market surpluses in these situations were analyzed in terms of “freebie” and “pure freebie”. An in-depth interview was conducted among students which revealed that 95% of respondents drew a parallel between “freebie” and luck but “freebie” can be prepared to. An interesting finding is the fact that parents’ money is perceived starting from the third year as a “freebie”, while in younger courses it perceived as the help of parents. When studying the issue of morality in a situation “freebie”, it turned out that if a “freebie” does not harm anyone, then this phenomenon is allowed and, moreover, is compared with entrepreneurial activity. Such phenomena as “free money” and “freeloader” as a stable “free” strategy were also analyzed. The latter was negatively judged by respondents. In conclusion, questions are raised for further research of the phenomenonСтатья посвящена проблемам поведенческой экономики в части изучения особенностей социально-экономических отношений, возникающих в случае товаров с нулевой ценой в их особой форме – «халяве», – как особой форме бесплатного (или почти бесплатного) получения товара. Исследование показало связь между экономическими и неэкономическими товарами. Дано определение понятию «халява» – ситуация получения товара, при которой физическое лицо (получатель) несет нулевые или незначительные экономические или физические издержки при высокой оценке полезности товара. Были рассмотрены три ситуации: получателем товара является потребитель, работник и особый случай работника – студент, получающий оценки в учебном процессе. Рыночные излишки в этих ситуациях анализированы в терминах «халява» и «чистая халява». Было проведено глубинное интервью среди студентов, которое показало, что 95 % респондентов проводят параллель между «халявой» и удачей, но «халява» может быть подготовлена. Интересным фактом является то, что деньги родителей с третьего курса воспринимаются студентами как «халява», а на младших курсах – как помощь. При изучении вопроса о морали в ситуации «халява» выяснено, что если «халява» никому не причиняет вреда, то это явление допускается и, более того, сравнивается с предпринимательской деятельностью. Были также проанализированы такие явления, как «свободные деньги» и «халявщик» как стабильная стратегия поиска бесплатных товаров. Последний вариант был отрицательно оценен респондентами. В заключении даны возможные дальнейшие направления исследования этого явлени