Cardiac Magnetic Resonance With T2-Weighted Imaging

Provide a no more than 200 word summary of this paper. Only the first 200 words will be considered: short bullet points are acceptable. Maximum of 6 points available.

The ideal study design for assessing a diagnostic test is outlined below.

(a) Describe the ‘patients suspected of target condition’? (1 point)
(b) Was this an appropriate group for the study? Give one reason for your answer (1 point)
(c) What was the gold standard test in this study? (1 point)
(d) Suggest one alternative gold standard that could have been used. (1 point)
(e) Why do you think the researchers did not use the alternative? (1 point)

The following quotes are taken from the methods section of the paper:

‘All physicians, including those in the ED, who were involved in the standard clinical care of the patients were blinded to the results on the CMR examination.’

‘Two experienced observers, who were blinded to the patients name and to all clinical data, evaluated all CMRs by consensus’

(a) What is the reason for blinding the physicians? (1 point)
(b) What is the reason for blinding the CMR observers? (1 point)

The following quote is taken from the statistical analysis section of the
paper:

‘Univariate associations between the baseline variables with the clinical diagnosis of ACS were examined with the Student t test for continuous variables and Chi-squared test for categorical variables.’

(a) What is a continuous variable? (1 point) Give 2 examples (1/2 point each)
(b) What is a categorical variable? (1 point) Give 2 examples (1/2 point each)

The paper presents the following results for the new CMR protocol:

Sensitivity 85%; Specificity 96%; PPV 85%; NPV 96%; Accuracy 93%;

(a) What percentage of patients with a positive ‘new CMR’ result had no ACS? (1 point)
(b) Comment on the ability of the test to rule out ACS. (2 points)
(c) Comment of the relative performance of the two CMR protocols (1 point)

The odds ratio for the traditional cardiac risk factors in detecting ACS is given as 1.88, 95% CI 0.99 to 3.58 per risk factor.

(a) Is this result statistically significant? (1 point)
(b) Give one reason for your answer. (1 point)

The chief executive of your hospital/trust has read the title of the paper and asks you about using the results to improve care in the hospital and avoid admissions. On the basis of the evidence in the paper, outline an argument for or against local implementation. Give 3 reasons for your stance. (3 points)