Volumetric rendering of MR images

The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis.     

Validity of self-reports of breast cancer treatment in low-income, medically underserved women with breast cancer

Few studies have assessed the agreement between subjects’ self-report and medical records among patients with breast cancer (BC), and none has addressed this issue in low-income women with BC. We assessed the level of agreement between self-report and medical records data for key BC treatment and prognostic characteristics using correct proportion and the Kappa statistic, among 726 low-income BC patients. Unconditional regression was used to investigate the association between accuracy of self-report and potential explanatory factors. Overall agreement between self-report and medical records was 95.3–99.6% for BC treatments including surgery, chemotherapy, radiotherapy and hormone therapy (Kappa = 0.79–0.99). Specific agreement was 87–89.5% for surgery type (Kappa = 0.51–0.96); 86.3% for chemotherapy completion (Kappa = 0.46) and 98.7% for radiotherapy completion (Kappa = 0.43); 95.2% for medical oncologist consultation (Kappa = 0.59) and 96% for radiation oncologist consultation; 97.3% for metastasis (Kappa = 0.56); and 93.6% for recurrence (Kappa = 0.30). When accepting answers within 15 days of the medical record date, 78.2% of women correctly reported surgery date, yet only around 55% of women correctly reported the start and/or end date of radiotherapy. Older age, less education, BC recurrence and poor patient–physician communication were associated with the lesser accuracy of patients’ self-report compared to medical records (P < 0.05). The results of this study suggest that self-reporting of key treatment and prognostic information is relatively accurate among low-income women with BC. Self-report seems to be a reliable source for accurate information when medical record review is unavailable or unfeasible. Interventions to enhance patient–physician communication may facilitate more accurate information reporting among vulnerable populations.     

003 胺碘酮可作为心房纤颤转复为窦性心律的首选药物

在美国，胺碘酮仅被批准用于治疗致命性室性心律失常，而在其他国家，尤其是南欧，也被广泛用于心房纤颤(Af)的治疗。然而有关胺碘酮复律效果报道不一，其成功率在16％～92％。本文前瞻性随机对照研究胺碘酮作为Af复律的首选药物的疗效及安全性。 连续208例症状性Af，男性102例，女性106例，年龄27～78(65±10)岁。将受试者随机分为胺碘酮治疗组与安慰剂组。胺碘酮用法：300mg静脉注射，持续1小时，然后以20mg/kg静脉滴注，持续24小时，继之口服200mg，tid，共1周，400mg/d共3周。如果受试者此前未用地高辛，则给予地高辛0.5mg静脉注射，2小时后再静脉注射0.25mg，继之静脉注射0.25mg，q6h，共24小时，此后调整地高辛剂量以维持治疗剂量的血清浓度，对Af持续48小时以上或持续时间不明、未用抗凝药物者均应用醋硝香豆素(acenocoumaro1)，至少21天，复律成功者继续用药21天，未成功者用药时间不定。本研究将Af持续1个月以上者定义为慢性Af，＜24小时者定义为新近发作Af，其余定义为持续性Af。     

Stroke volume measurements with first-pass dynamic positron emission tomography: Comparison with cardiovascular magnetic resonance

Background  The assessment of forward stroke volume (SV) using dynamic, first-pass cardiac positron emission tomography (PET) was shown to be feasible in a limited number of studies with small numbers of subjects. The aim of this study was to compare first-pass derived SV with cardiovascular magnetic resonance imaging (CMR)-obtained values in a larger population of subjects. Methods and Results  Fifty-nine subjects with varying degrees of cardiac function were studied. Stroke volume was assessed using oxygen-15-labeled water (H₂ ¹⁵O) dynamic first-pass PET for both the right ventricle (RV) and left ventricle (LV), and compared with the findings of aorta velocity-encoded phase-contrast CMR. The PET-estimated SV was higher for the RV than for the LV (133±34 vs 116±31 mL, P<.01, ±SD), and both were higher compared with values obtained by CMR (81±20 mL, both P<.01,±SD). Although significant, the correlations between PET and CMR were moderate for both the RV (r=0.37, P<.01) and the LV (r=0.40, P<.01,±SD). Bland-Altman analysis revealed a progressive overestimation with increasing SV measured in either ventricle. Conclusions  First-pass dynamic H₂ ¹⁵O PET for the assessment of forward SV is feasible, although values are progressively overestimated with increasing SV, particularly when the RV is used, and correlations with aorta velocity-encoded phase-contrast CMR are moderate. These findings are probably protocol-dependent and warrant further study before the use of first-pass dynamic H₂ ¹⁵O PET in clinical or research settings can be advocated.     

Preventive HIV Vaccine Acceptability and Behavioral Risk Compensation among a Random Sample of High-Risk Adults in Los Angeles (LA VOICES)

Objective. To assess HIV vaccine acceptability among high‐risk adults in Los Angeles. Study Setting. Sexually transmitted disease clinics, needle/syringe exchange programs, Latino community health/HIV prevention programs. Study Design. Cross‐sectional survey using conjoint analysis. Participants were randomly selected using three‐stage probability sampling. Data Collection. Sixty‐minute structured interviews. Participants rated acceptability of eight hypothetical vaccines, each with seven dichotomous attributes, and reported post‐vaccination risk behavior intentions. Principal Findings. Participants (n=1164; 55.7 percent male, 82.4 percent ethnic minority, mean age=37.4 years) rated HIV vaccine acceptability from 28.4 to 88.6; mean=54.5 (SD=18.8; 100‐point scale). Efficacy had the greatest impact on acceptability, followed by side effects and out‐of‐pocket cost. Ten percent would decrease condom use after vaccination. Conclusions. Findings support development of social marketing interventions to increase acceptability of “partial efficacy” vaccines, behavioral interventions to mitigate risk compensation, and targeted cost subsidies.     

A near-fatal reaction during granulocyte transfusion of a neonate

Although reactions to granulocyte transfusions in neonates are rarely reported, we observed a near-fatal pulmonary reaction, presumably due to white cell antibodies, in a neonate with Rh hemolytic disease. The hemolytic disease was being treated with exchange transfusions, and at 2 days after the infant's birth, bacterial sepsis was suspected and granulocyte transfusions were begun. The first granulocyte transfusion (Day 3) was uneventful. Five minutes after the beginning of the second granulocyte transfusion (Day 4), severe respiratory distress, hypotension, bradycardia, cyanosis, and acidosis suddenly occurred. The infant's serum obtained after the reaction contained granulocytotoxic and B-lymphocytotoxic antibodies that reacted with leukocytes from the second granulocyte donor. Antibodies could not be detected either in the initial infant serum or in maternal serum. However, an antileukocyte antibody was present in the serum of a parous woman donor. We used plasma from this woman to prepare reconstituted whole blood for the exchange transfusion that we performed immediately preceding the second granulocyte transfusion. Despite the sequence of events, an irrefutable cause-and-effect mechanism could not be established because the properties of the donor and neonatal antibodies were similar, but not identical. However, this catastrophic event emphasizes both the potential for adverse effects of granulocyte transfusions in neonates and the need for caution when transfusing blood from parous women.     

Muscle fibre types, ubiquinone content and exercise capacity in hypertension and effort angina

The composition of skeletal muscle fibre expressed as a percentage of slow twitch (ST), type I or "red" and fast twitch (FT), type II or "white" were determined in patients with hypertension (HT) or with severe ischaemic heart disease (IHD) and compared to age matched controls. Similarly, exercise capacity expressed as the cycle intensity eliciting a blood lactate concentration corresponding to 2.0 mmol x 1-1 were compared with healthy controls. Both patient groups had a higher percentage of FT fibres with relatively lower exercise capacities than their controls. The exercise capacities were reduced even when the relationship of decreased capacity with the percentage of increased FT was considered. There was an increase IHD but not in HT in patients with fibre subgroup FTc, which most probably reflected fibre trauma. Both patient groups were low in the skeletal muscle mitochondrial electron carrier and unspecific antioxidant ubiquinone, coenzyme Q10 or CoQ10. Patients with IHD but not HT showed, however, a faster fall in the ratio CoQ10 over ST% the higher the percentage value of ST. The ratio reflects the antioxidant activity related to CoQ10 in the fibre hosting most of the oxidative metabolism. A low ratio indicates a risk of metabolic lesion and cell trauma. This could explain fibre plasticity and offer an alternative cause to heredity in elucidating in deviating muscle fibre composition in patients with HT and IHD.     

Magnetic resonance assessment of aortic pulse wave velocity, aortic distensibility, and cardiac function in uncomplicated type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus (DM2) may augment arterial stiffening and thereby modulates left ventricular (LV) function. Cardiovascular magnetic resonance (CMR) is well suited to assess aortic pulse wave velocity (PWV) and aortic distensibility, both markers of arterial stiffness, without the use of geometric assumptions. Furthermore, CMR is a reliable method for assessing left ventricular (LV) function. The purpose of this study was to assess LV function, PWV, and aortic distensibility in patients with DM2 using MR. METHODS: Fourteen patients with well controlled, uncomplicated DM2, and 16 age and gender matched healthy subjects were included. PWV was calculated based on MR velocity mapping at two predefined aortic locations. Aortic distensibility was measured in the mid ascending aorta. LV volumes were measured by fast gradient-echo imaging to assess systolic function. Furthermore, mitral inflow was measured by MR velocity mapping to assess diastolic LV function. RESULTS: Mean PWV was higher in patients as compared to healthy subjects (6.83 +/- 1.60 m/s vs. 5.65 +/- 0.75 m/s, p < 0.05). This difference was independent of blood pressure. PWV correlated significantly (p < 0.05) with fasting plasma glucose and insulin levels. Aortic distensibility was lower in patients as compared to healthy subjects (4.50 x 10(- 3)+/- 2.24 x 10(- 3) mmHg(- 1) vs. 7.42 x 10(- 3)+/- 3.34 x 10(- 3) mmHg(- 1), p < 0.05). Distensibility correlated negatively with PWV and positively with LV diastolic function (p < 0.05). CONCLUSION: A combined CMR assessment of aortic PWV, aortic distensibility, and heart function reveals abnormal PWV and distensibility in patients with DM2, independent of blood pressure. Furthermore, aortic distensibility correlates with diastolic left ventricular function.