Contrast monitoring techniques in CT pulmonary angiography: An important and underappreciated contributor to breast dose.

OBJECTIVE: The aims of our study were to evaluate the contribution of contrast-monitoring techniques to breast dose in pregnant and non-pregnant women, and to investigate the effect of a reduced peak kilovoltage (kV) monitoring scan protocol on breast dose and Computed Tomography Pulmonary Angiography (CTPA) diagnostic quality. MATERIALS AND METHODS: Single center retrospective study of 221 female patients undergoing a reduced kV 80kV contrast-monitoring CTPA protocol compared to 281 patients using the conventional 120kV contrast-monitoring protocol (Siemens Somatom Definition AS+). 99 pregnant patients analyzed separately. ImPACT dosimetry software was used to calculate dose. Group subsets were evaluated to assess CTPA diagnostic quality. RESULTS: The contrast-monitoring component of a CTPA study constituted 27% of the overall breast dose when using a standard 120kV protocol compared to only 7% of the overall breast dose in the 80kV study group. The dose to the breast from the contrast-monitoring component alone was reduced by 79% in the non-pregnant patients (0.36mGy±0.37 versus 1.7mGy±1.02; p<0.001), and by 88% in the pregnant population (0.25mGy±0.67 versus 2.24mGy±1.61; p<0.001). There was no statistical difference in CTPA diagnostic quality or timing. CONCLUSION: Despite a short scan length and relatively small DLP, contrast-monitoring techniques (test-bolus or bolus-tracked) set at 120kV can account for 27% of the overall breast dose accrued from a CTPA study. By decreasing the kilovoltage of the contrast-monitoring component, a significant reduction in breast dose for pregnant and non-pregnant female patients can be achieved without affecting CTPA quality or timing.

Cryptosporidiosis in children who visited an open farm.

In the summer of 1995, cryptosporidiosis was diagnosed in a child in hospital. This child had taken part in a summer activity project involving 161 children and nine adults. Reports of a similar illness among a number of other participants prompted an outbreak investigation. A cohort study was conducted in two phases. Thirteen children (aged 6 to 15 years) out of 161 respondents to the first questionnaire met the case definition for illness and cryptosporidium was detected in stools from seven of the 13. Illness was significantly associated with child participants who had visited an open farm (p < .000005). Nine of the cases sought medical attention, and two were admitted to hospital. The second phase of the cohort study was conducted among 52 of the 55 people who had visited the open farm. Illness was significantly associated with playing in sand to which animals had access, at the edge of a stream beside a picnic area (p < .005). Contact with various animals was not associated with illness. This outbreak emphasises the risk for children of visiting open farms. Managers of open farms need to be aware of the potential for transmission of infectious diseases to visiting children. Strict implementation of hygiene measures is essential to minimise risk.

The hospital in-patient enquiry scheme: a study of data accuracy and capture.

In order to measure the coverage and accuracy of the Hospital In-patient Enquiry Scheme data in a large acute hospital in Dublin, 793 patient charts were selected randomly from all the discharges in 1990. The capture rate was 56%. Whether a diagnosis was captured for the Hospital In-patient Enquiry Scheme depended partly upon geographical factors within the hospital and partly upon the nature of the diagnosis. "Non-capture" was not random and was particularly likely to occur where the case was complex, e.g. oncology, HIV infection. The coding accuracy of primary diagnoses was 59% and the completeness of recording of secondary diagnoses was 56%. Both were significantly associated with the presence in the hospital chart of discharge summaries and with the clarity and source of written diagnoses. The factors that affected accuracy were not the same as those affecting the capture rate.

Suxamethonium-induced hyperkalaemia following cold injury.

Within the space of 9 days, a 4-month-old baby requiring cardiac surgery was exposed to two periods of hypothermic circulatory arrest for surgery, and prolonged surface cooling postoperatively. At the end of this period, the administration of suxamethonium was associated with a marked rise in serum potassium.

Spin labeling studies of the interactions of P815 mouse mastocytoma cells with antiserum to histocompatibility antigens, H-2d.

The effect of antiserum to histocompatibility antigens on the membrane organization of murine neoplastic mast cells (P815) has been studied by spin labeling. Incubation of in vivo passaged cells, labeled with a nitroxide derivative of methyl stearate, with antiserum to membrane carried histocompatibility antigens, H-2d, resulted in an apparent decrease in membrane fluidity that was accompanied by histamine release. This electron spin resonance (esr) detectable change was found to be temperature, time, and dose dependent. Treatment of the cells with cytochalasin B, a drug disrupting microfilament structure, inhibited the effects induced by H-2d antiserum. In contrast, vinblastine, which disrupts microtubules, did not modulate the effect of this antiserum. Other data presented here suggest that some of the large spectral change observed on treatment of the cells with anti-H-2d serum may result from hydrolysis of the spin label fatty acid ester via activation of a membrane-associated esterase. The relationship of these results to other immunologically induced membrane phenomena is discussed.