MRI techniques for cardiovascular imaging.

Over the last several years, cardiovascular MRI has benefited from a number of technical advances which have improved routine clinical imaging techniques. As a result, MRI is now well positioned to realize its longstanding promise of becoming the comprehensive cardiac imaging test of choice in many clinical settings. This may be achieved using a combination of basic advanced techniques. In this overview, the basic cardiac MRI techniques which are clinically useful are reviewed, and the recent technical advances which are clinically promising are described. These advances include routine black blood and cine bright blood techniques that are high speed (<10s per black blood image or cine slice), multislice whole heart perfusion imaging methods, and recently emerging real-time imaging methodologies. J Magn. Reson. Imaging 1999;10:590-601.     

Coronary MR angiography at 3T during diastole and systole

PURPOSE: To investigate the impact of end-systolic imaging on quality of right coronary magnetic resonance angiography (MRA) in comparison to diastolic and to study the effect of RR interval variability on image quality. MATERIALS AND METHODS: The right coronary artery (RCA) of 10 normal volunteers was imaged at 3T using parallel imaging (sensitivity encoding [SENSE]). Navigator-gated three-dimensional (3D) gradient echo was used three times: 1) end-systolic short acquisition (SS): 35-msec window; 2) diastolic short (DS): middiastolic acquisition using 35-msec window; and 3) diastolic long (DL): 75-msec diastolic acquisition window. Vectorcardiogram (VCG) data was used to analyze RR variability. Vessel sharpness, length, and diameter were compared to each other and correlated with RR variability. Blinded qualitative image scores of the images were compared. RESULTS: Quantitative and qualitative parameters were not significantly different and showed no significant correlation with RR variability. CONCLUSION: Imaging the RCA at 3T during the end-systolic rest period using SENSE is possible without significant detrimental effect on image quality. Breaking away from the standard of imaging only during diastole can potentially improve image quality in tachycardic patients or used for simultaneous imaging during both periods in a single scan.     

The changing face of perceptual rivalry

Functional brain-imaging studies of house-face binocular rivalry and Rubin's vase-faces illusion have consistently reported face perception-dependent activity in the right fusiform gyrus. Here we use Rubin's illusion and report that activation of the left hemisphere by caloric vestibular stimulation increases the predominance of the faces percept in a substantial number of test subjects. While partially supporting the brain-imaging lateralization reports, our findings also challenge these studies by suggesting that neural mechanisms of Rubin's illusion cannot be limited to extrastriate perception-dependent processing. In accordance with our previously proposed interhemispheric switch model, the present findings support the notion that perceptual rivalry engages high-level cortical structures that mediate unihemispheric attentional selection.     

Sleep in the platypus.

We have conducted the first study of sleep in the platypus Ornithorhynchus anatinus. Periods of quiet sleep, characterized by raised arousal thresholds, elevated electroencephalogram amplitude and motor and autonomic quiescence, occupied 6-8 h/day. The platypus also had rapid eye movement sleep as defined by atonia with rapid eye movements, twitching and the electrocardiogram pattern of rapid eye movement. However, this state occurred while the electroencephalogram was moderate or high in voltage, as in non-rapid eye movement sleep in adult and marsupial mammals. This suggests that the low-voltage electroencephalogram is a more recently evolved feature of mammalian rapid eye movement sleep. Rapid eye movement sleep occupied 5.8-8 h/day in the platypus, more than in any other animal. Our findings indicate that rapid eye movement sleep may have been present in large amounts in the first mammals and suggest that it may have evolved in pre-mammalian reptiles.     

Accuracy of the Surgeons’ Clinical Prediction of Perioperative Complications Using a Visual Analog Scale

Background The ability to predict who will develop perioperative complications remains difficult because the etiology of adverse events is multifactorial. This study examines the preoperative and postoperative ability of the surgeon to predict complications and assesses the significance of a change in prediction. Methods This was a prospective study of 1013 patients. The surgeon assessed the risk of a major complication on a 100-mm visual analog scale (VAS) immediately before and after surgery. When the VAS score was changed, the surgeon was asked to document why. Patients were assessed up to 30 days postoperatively. Results Surgeons made a meaningful preoperative prediction of major complications (median score = 27mm vs. 19mm, p < 0.01), with an area under the receiver operating characteristic curve of 0.74 for mortality, 0.67 for major complications, and 0.63 for all complications. A change in the VAS score postoperatively was due to technical reasons in 74% of stated cases. An increased VAS score identified significantly more complications, but the improvement in the discrimination was small. When included in a multivariate model for predicting postoperative complications, the surgeon’s VAS score functioned as an independent predictive variable and improved the predictive ability, goodness of fit, and discrimination of the model. Conclusions Clinical assessment of risk by the surgeon using a VAS score independently improves the prediction of perioperative complications. Including the unique contribution of the surgeon’s clinical assessment should be considered in models designed to predict the risk of surgery.     

American Society of Anesthesiologists classification of physical status as a predictor of wound infection

BACKGROUND: Wound infection occurs when bacterial contamination overcomes the hosts' defences against bacterial growth. Wound categories are a measurement of wound contamination. The American Society of Anesthesiologists (ASA) classification of physical status may be an effective indirect measurement of the hosts' defence against infection. This study examines the association between the ASA score of physical status and wound infection. METHODS: A retrospective review of a prospective study of antibiotic prophylaxis was carried out. Patients with a documented ASA score who received optimal prophylactic antibiotics were included. The anaesthetist scored the ASA classification of physical status in theatre. Other risk factors for wound infection were also documented. Patients were assessed up to 30 days postoperatively. RESULTS: Of 1013 patients there were 483 with a documented ASA score. One hundred and one may not have received optimal prophylaxis, leaving a database of 382 patients. There were 36 wound infections (9.4%). Both the ASA classification of physical status (P = 0.002) and the wound categories (P = 0.034) significantly predicted wound infection. The duration of surgery, patient's age, acuteness of surgery and the organ system being operated on did not predict wound infection. On logistic regression analysis the ASA score was the strongest predictor of wound infection. CONCLUSION: When effective prophylactic antibiotics were used the ASA classification of physical status was the most significant predictor of wound infection.     

Drinking Refusal Self-Efficacy and Intended Alcohol Consumption During a Mass-Attended Youth Event

Background: Mass-attended youth events represent a substantial public health challenge due to high levels of alcohol consumption and corresponding high rates of alcohol-related harm. Although previous research has documented the protective effect of high drinking refusal self-efficacy (DRSE) on alcohol consumption in general, there is a lack of research examining the role of DRSE in reducing consumption during mass-attended youth events and the factors associated with DRSE in these contexts. Objectives: This study aimed to identify potentially modifiable factors that influence DRSE and drinking intentions to inform interventions designed to reduce alcohol-related harm during mass-attended events. Methods: Australian secondary school students (n = 586; 70% female) in their final two years of high school completed an online survey assessing their alcohol consumption intentions for Schoolies, their perceived degree of DRSE, and other individual and environmental factors. Path analysis was used to assess a mediational model examining factors associated with DRSE and alcohol consumption intentions. Results: DRSE was found to be significantly associated with intended alcohol consumption during Schoolies. Specifically, leavers who believed they would not be able to refuse others' offers of alcoholic drinks reported significantly greater alcohol consumption intentions. Results also revealed that DRSE was enhanced in those respondents who believed there would be a variety of non-drinking activities and non-alcoholic beverages available to them during Schoolies. Conclusion: Results suggest the need to increase leavers' confidence in their ability to refuse unwanted alcoholic beverages and highlight the importance of providing celebration options that do not involve alcohol consumption.     

Are chronic hepatitis C viral infections more benign in patients with hemophilia?

BACKGROUND AND AIMS: Cirrhosis is associated with thromboses of the intrahepatic vasculature. This raises the possibility that HCV infections in hemophiliacs may differ from those in non-hemophiliacs METHODS: Liver biopsy findings from 12 hemophiliacs and 20 age- and gender-matched, non-hemophiliac controls with chronic hepatitis C viral (HCV) infections were compared for inflammatory activity and fibrosis. RESULTS: The mean ages of hemophiliacs and controls were 35.0 +/- 3.0 yr and 39.6 +/- 5.6 yr, respectively (P= 0.2). Serum aspartate aminotransferase (AST) levels were lower (44 +/- 13 vs 70 +/- 43 U/L) and the duration of the partial thromboplastin (PTT) time longer (49.2 +/- 16.9 vs 31.2 +/- 1.2 s.) in hemophiliacs than in controls (P < 0.02 and <0.001, respectively). Six of the seven hemophiliac patients (86%) and 8/17 controls (46%) were infected with genotypes 1a or 1b with the remainder being infected with 2b, 3a, or 3b. Histological activity and fibrosis scores were significantly lower in hemophiliacs than in controls (1.9 +/- 0.6 vs 3.6 +/- 2.7 and 0.3 +/- 0.2 vs 1.5 +/- 1.5, P < 0.05 and P < 0.01, respectively). None of the hemophiliacs had histological evidence of advanced disease (bridging fibrosis and/or cirrhosis) as compared to 7/20 (30%) controls (P < 0.05). CONCLUSION: HCV infections in hemophiliacs may be less severe than in HCV infected patients without hemophilia.     

Serving seniors better: service guidelines for supermarkets

Objective: Generate a list of service guidelines to enable supermarket managers to accommodate the needs of their older customers. Methods: Focus groups and a national telephone survey were conducted with Australian seniors to generate 10 service guidelines for supermarkets. Results: The 10 guidelines produced are considered to be of significant importance by Australian seniors, with some apparent differences in importance and relevance ratings between older and younger seniors, and males and females. Conclusions: Seniors have distinct service preferences when grocery shopping and their needs require special attention in the supermarket environment. In particular, they feel strongly about the quality of staff and equipment with which they come into contact.     

Reproducibility of free-breathing cardiovascular magnetic resonance coronary angiography.

OBJECTIVE: Contemporary free-breathing non contrast enhanced cardiovascular magnetic resonance angiography (CMRA) was qualitatively and quantitatively evaluated to ascertain the reproducibility of the method for coronary artery luminal dimension measurements. SUBJECTS AND METHODS: Twenty-two healthy volunteers (mean age 32 +/- 7 years, 12 males) without coronary artery disease were imaged at 2 centers (1 each in Europe and North America) using navigator-gated and corrected SSFP CMRA on a commercial whole body 1.5T System. Repeat images of right (RCA, n = 21), left anterior descending (LAD, n = 14) and left circumflex (LCX, n = 14) coronary arteries were obtained in separate sessions using identical scan protocol and imaging parameters. True visible vessel length, signal-to-noise (SNR), contrast-to-noise ratios (CNR) and the average luminal diameter over the first 4 cm of the vessel were measured. Intra-observer, inter-observer and inter-scan reproducibility of coronary artery luminal diameter were determined using Pearson's correlation, Bland-Altman analysis and intraclass correlation coefficients (ICC). RESULTS: CNR, SNR and the mean length of the RCA, LAD and LCX imaged for original and repeat scans were not significantly different (all p > 0.30). There was a high degree of intra-observer, inter-observer and inter-scan agreements for RCA, LAD and LCX luminal diameter respectively on Bland-Altman and ICC analysis (ICC's for RCA: 0.98. 0.98 and 0.86; LAD: 0.89, 0.89 and 0.63; LCX: 0.95, 0.94 and 0.79). CONCLUSION: In a 2-center study, we demonstrate that free-breathing 3D SSFP CMRA can visualize long continuous segments of coronary vessels with highly reproducible measurements of luminal diameter.