Improving dynamic susceptibility contrast MRI measurement of quantitative cerebral blood flow using corrections for partial volume and nonlinear contrast relaxivity: A xenon computed tomographic comparative study.

PURPOSE: To test whether dynamic susceptibility contrast MRI-based CBF measurements are improved with arterial input function (AIF) partial volume (PV) and nonlinear contrast relaxivity correction, using a gold-standard CBF method, xenon computed tomography (xeCT). MATERIALS AND METHODS: Eighteen patients with cerebrovascular disease underwent xeCT and MRI within 36 h. PV was measured as the ratio of the area under the AIF and the venous output function (VOF) concentration curves. A correction was applied to account for the nonlinear relaxivity of bulk blood (BB). Mean CBF was measured with both techniques and regression analyses both within and between patients were performed. RESULTS: Mean xeCT CBF was 43.3 +/- 13.7 mL/100g/min (mean +/- SD). BB correction decreased CBF by a factor of 4.7 +/- 0.4, but did not affect precision. The least-biased CBF measurement was with BB but without PV correction (45.8 +/- 17.2 mL/100 g/min, coefficient of variation [COV] = 32%). Precision improved with PV correction, although absolute CBF was mildly underestimated (34.3 +/- 10.8 mL/100 g/min, COV = 27%). Between patients correlation was moderate even with both corrections (R = 0.53). CONCLUSION: Corrections for AIF PV and nonlinear BB relaxivity improve bolus MRI-based CBF maps. However, there remain challenges given the moderate between-patient correlation, which limit diagnostic confidence of such measurements in individual patients.

Simulated parents: developing paediatric trainees' skills in giving bad news.

AIM: In curriculum documents for medicine in undergraduate, post-graduate and continuing professional development, there is now a focus on communication skills. The challenges are to place communication skills in the crowded curriculum and then to construct and sustain a programme that uses an evidence-based approach to the teaching and learning of communication skills. For 6 years, we have conducted a programme that involves simulated parents supporting junior medical staff to refine their skills in communication, particularly in giving parents bad news. The aim of our study was to obtain a better understanding of the trainees' experiences of the programme. METHODS: Nine junior residents individually worked through two scenarios and received feedback from the simulated parent. They gave bad news to a simulated parent/actor who then gave feedback. A recording of the simulation was provided for discussion with a designated colleague at an arranged time. The tapes were then separately appraised by two independent raters - another actor and a paediatrician. Brief written reports and conducted semi-structured interviews provided more insights into the trainees' experience of the simulation. Other participating medical/medical education staff were interviewed about the simulation programme. RESULTS: Five themes emerged from the qualitative data: timeliness, emotional safety, the complexity of communication, practical usefulness and the challenge of effecting change. In addition, the ratings of the videos helped to clarify those 'parent-centred' communication skills that trainees may neglect in difficult conversations: 'ask about support', 'encourage the parent to ask questions' and 'repeat key messages'. CONCLUSION: The evaluation highlighted the value of an early-career experiential programme to highlight the importance of communication skills in post-graduate paediatrics practice.