Diagnostic performance of susceptibility-weighted magnetic resonance imaging for the detection of calcifications: A systematic review and meta-analysis

Abstract

Since its introduction, susceptibility-weighted-magnetic resonance imaging (SW-MRI) has shown the potential to overcome the insensitivity of MRI to calcification. Previous studies reporting the diagnostic performance of SW-MRI and magnetic resonance imaging (MRI) for the detection of calcifications are inconsistent and based on single-institution designs. To our knowledge, this is the first meta-analysis on SW-MRI, determining the potential of SW-MRI to detect calcifications. Two independent investigators searched MEDLINE, EMBASE and Web of Science for eligible diagnostic accuracy studies, which were published until March 24, 2017 and investigated the accuracy of SW-MRI to detect calcifications, using computed tomography (CT) as a reference. The QUADAS-2 tool was used to assess study quality and methods for analysis were based on PRISMA. A bivariate diagnostic random-effects model was applied to obtain pooled sensitivities and specificities. Out of the 4629 studies retrieved by systematic literature search, 12 clinical studies with 962 patients and a total of 1,032 calcifications were included. Pooled sensitivity was 86.5% (95%-confidence interval (CI): 73.6-93.7%) for SW-MRI and 36.7% (95%-CI:29.2-44.8%) for standard MRI. Pooled specificities of SW-MRI (90.8%; 95%-CI:81.0-95.8%) and standard MRI (94.2; 95%-CI:88.9-96.7%) were comparable. Results of the present meta-analysis suggest, that SW-MRI is a reliable method for detecting calcifications in soft tissues.

Figure 1

Study selection flowchart.

Figure 2

QUADAS-2 assessment of study quality. Grouped bar charts of the QUADAS-2 scores are expressed as percentage of the 12 included studies meeting each criterion. For each domain, the proportion of the included studies that indicate low/high/unclear concerns of applicability or risk of bias are displayed in light grey = “yes” answers (good quality), dark grey bar = “unclear” answers, and medium bar = “no” answers (low quality).

Figure 3

Forest plots showing the log diagnostic odds ratios (black squares) for susceptibility weighted imaging and standard magnetic resonance imaging (MRI) (where available) of each study with 95% confidence intervals (horizontal lines). The area of each square is proportional to the study’s weight in the meta-analysis and the summary measure of effect is plotted below as a diamond. An effect size of zero is indicated by the vertical dashed line.

Figure 4

Summary ROC curves of overall diagnostic accuracy for susceptibility weighted magnetic resonance imaging (SW-MRI) and magnetic resonance imaging (MRI) (A), for the overall diagnostic accuracy of SW-MRI (B) and the overall diagnostic accuracy of MRI (C). The false positive rate (1-specificity) is plotted against the false positive rate (1-specificity). The sROC curves show a deviation of the data points and especially for standard MRI, the extrapolation of the sROC curve is highly vulnerable to outliners.