CT protocol optimisation in PET/CT: a systematic review.

PURPOSE: Currently, no consistent guidelines for CT scans used within PET/CT examinations are available. This systematic review provides an up-to-date overview of studies to answer the following questions: What are the specific CT protocols used in PET/CT? What are the possible purposes of requiring a CT study within a PET/CT scan? Is the CT protocol obtained from a dosimetric optimisation study? MATERIALS AND METHOD: PubMed/MEDLINE, Cochrane Library, Embase and Scopus were systematically searched for relevant studies in accordance with the PRISMA statement. The literature search was conducted from January 2007 until June 2019. Data derived from studies were standardized in order to reduce possible biases, and they were divided into clinically homogeneous subgroups (adult, child or phantom). Subsequently, we divided the CT protocol intents into 3 types (anatomic localization only, attenuation correction only and diagnostic purpose). A narrative approach was used to summarise datasets and to investigate their heterogeneity (due to medical prescription methodology) and their combination in multiseries CT protocols. When weighted computed tomography dose index (CTDIw) was available, we calculated the volumetric computed tomography dose index (CTDIvol) using the pitch value to make the results uniform. Eventually, the correlation between protocol intents and CTDIvol values was obtained using a Kruskal-Wallis one-way ANOVA statistical test. RESULT: Starting from a total of 1440 retrieved records, twenty-four studies were eligible for inclusion in addition to two large multicentric works that we used to compare the results. We analyzed 87 CT protocols. There was a considerable range of variation in the acquisition parameters: tube current-time product revealed to have the most variable range, which was 10-300 mAs for adults and 10-80 mAs for paediatric patients. Seventy percent of datasets presented scans acquired with tube current modulation, 9% used fixed tube current and in 21% of them, this information was not available. Dependence between mean CTDIvol values and protocol intent was statistically significant (p = 0.002). As expected, in diagnostic protocols, there was a statistically significant difference between CTDIvol values of with and without contrast acquisitions (11.68 mGy vs 7.99 mGy, p = 0.009). In 13 out of 87 studies, the optimisation aim was not reported; in 2 papers, a clinical protocol was used; and in 11 works, a dose optimisation protocol was applied. CONCLUSIONS: According to this review, the dose optimisation in PET/CT exams depends heavily on the correct implementation of the CT protocol. In addition to this, considering the latest technology advances (i.e. iterative algorithms development), we suggest a periodic quality control audit to stay updated on new clinical utility modalities and to achieve a shared standardisation of clinical protocols. In conclusion, this study pointed out the necessity to better identify the specific CT protocol use within PET/CT scans, taking into account the continuous development of new technologies.

The effects of mindfulness-based stress reduction program on the mental health of family caregivers: a randomized controlled trial.

BACKGROUND: Caregivers of people with chronic conditions are more likely than non-caregivers to have depression and emotional problems. Few studies have examined the effectiveness of mindfulness-based stress reduction (MBSR) in improving their mental well-being. METHODS: Caregivers of persons with chronic conditions who scored 7 or above in the Caregiver Strain Index were randomly assigned to the 8-week MBSR group (n = 70) or the self-help control group (n = 71). Validated instruments were used to assess the changes in depressive and anxiety symptoms, quality of life, self-efficacy, self-compassion and mindfulness. Assessments were conducted at baseline, post-intervention and at the 3-month follow-up. RESULTS: Compared to the participants in the control group, participants in the MBSR group had a significantly greater decrease in depressive symptoms at post-intervention and at 3 months post-intervention (p < 0.01). The improvement in state anxiety symptoms was significantly greater among participants in the MBSR group than those of the control group at post-intervention (p = 0.007), although this difference was not statistically significant at 3 months post-intervention (p = 0.084). There was also a statistically significant larger increase in self-efficacy (controlling negative thoughts; p = 0.041) and mindfulness (p = 0.001) among participants in the MBSR group at the 3-month follow-up compared to the participants in the control group. No statistically significant group effects (MBSR vs. control) were found in perceived stress, quality of life or self-compassion. CONCLUSIONS: MBSR appears to be a feasible and acceptable intervention to improve mental health among family caregivers with significant care burden, although further studies that include an active control group are needed to make the findings more conclusive.

Sex steroids in autoimmune diseases.

A sexual dysmorphism in the immune response has been described and females display an increased incidence of autoimmune diseases. Experimental data show that sex steroids influence immune cell development and have immunomodulatory effects. The distribution, the action (genomic and nongenomic), the sex and tissue-depending expression pattern of estrogen, progesterone and androgen receptors and their functional disruptions in corresponding receptor knockout animals will be discussed, pointing out the difference among sex steroid hormones. Recent advances indicate an immunomodulatory role of sex steroids in the pathogenesis of systemic lupus erythematosus, multiple sclerosis and rheumatoid arthritis. The outcomes of the clinical trials will help to find the best use of sex steroids in combination with current therapeutic drugs in autoimmune diseases. Sex steroid receptor modulating drugs will provide new therapeutic approaches in these pathologies.

The Effects of Rumination and Depressive Symptoms on the Prediction of Negative Attributional Style Among College Students.

Research on cognitive vulnerability to depression has identified negative cognitive style and rumination as distinct risk factors for depression but how rumination would influence negative cognitive style remains unclear. The present study investigated the relationship between rumination and negative attributional style and specifically tested the potential moderating effect of depressive symptoms and processing mode during rumination on activating negative attributional style. After completing the baseline measures of depressive symptoms, dysphoric affect, and negative attributional style, participants were randomly assigned to three experimental conditions: analytical self-focus, experiential self-focus, and distraction, in which the degree of self-focus and mode of processing were manipulated. A second set of mood and cognitive measures was administered afterwards. Results showed that a stronger positive relationship between negative attributional style and level of depressive symptoms was found in the analytical self-focus condition, relative to the experiential and distraction conditions. This finding suggested that processing mode in rumination interacted with depressive symptoms to predict negative attributional style.

The effects of rumination and negative cognitive styles on depression: a mediation analysis.

Research on cognitive models of depression has identified negative cognitive styles and rumination as risk factors for depression. The present study examined the hypothesis that rumination mediates the effect of negative cognitive styles on depression. Specifically, we evaluated the differential effects of two aspects of rumination, characterized by brooding and reflection, on the relationship between negative cognitive styles and level of depressive symptoms. A total of 115 college students and 38 patients suffering from depressive disorders completed a battery of questionnaires measuring levels of depressive symptoms, brooding, reflection, and negative cognitive styles. The results support the notion that there exist two distinct dimensions of rumination and that, of the two, it is brooding and not reflection that mediates the relationship between negative cognitive styles and depression and contributes to its negative outcomes.

Residual insulin secretion at diagnosis of type 1 diabetes is independently associated with both, age of onset and HLA genotype.

BACKGROUND: We investigated whether residual insulin secretion and metabolic derangement at diagnosis of type 1 diabetes (T1DM) are influenced by human leukocyte antigens (HLA) class II genes. METHODS: Eight hundred and seventy-one T1DM consecutive Caucasian patients were typed for HLA class II genes. In 300 of these patients, glycated haemoglobin, insulin requirement, baseline C-peptide and body mass index (BMI) Z-score were measured at clinical diagnosis. The effect of the HLA genotypes on the quantitative variables was investigated using multiple linear regression. The beta coefficient regression of the age at onset and HLA genotypes were standardized to compare their specific importance for C-peptide levels. RESULTS: The HLA genotypes were divided in high-, moderate- and low-risk categories. The frequency of high-risk genotype, DRB1*03-DQB1*0201/DRB1*04-DQB1*0302, decreased with increasing age of onset (p < 0.0001, chi(2) linear trend). The presence of the high-risk genotype was independently associated with lower C-peptide levels at diagnosis (p = 0.002). In the regression analysis of C-peptide levels, the standardized beta coefficient for age of onset and high risk compared to low-risk genotypes showed similar results (0.27 and 0.24 respectively). There was a positive association between age of onset and C-peptide (p < 0.0001) and a negative association between age of onset and insulin requirement (p < 0.0001). CONCLUSIONS: The degree of beta-cell destruction at diagnosis of T1DM is independently associated with both, age of onset and HLA genotypes, the two variables exert a similar quantitative effect on residual beta-cell function at diagnosis.