Table 3

Sensitivity per aneurysm for combinations of non-invasive tests

Modality Size of aneurysm Sensitivity (95% CI) (TP/TP+FN) Specificity (95% CI) (TN/TN+FP)
CTA+TCD3-150 <3 mm0.00 (0.00–0.31) (0/10)
(64 “uncertain”)3–5 mm0.43 (0.23–0.66) (10/23)
5.1–10 mm0.71 (0.29–0.96) (5/7)
>10 mm1.00 (0.59–1.00) (7/7)
All0.47 (0.32–0.62) (22/47)0.95 (0.86–0.99) (58/61)
MRA+TCD3-150 <3 mm0.00 (0.00–0.22) (0/15)
(55 “uncertain”)3–5 mm0.26 (0.10–0.48) (6/23)
5.1–10 mm0.63 (0.24–0.91) (5/8)
>10 mm1.00 (0.54–1.00) (10/10)
All0.38 (0.25–0.51) (21/56)0.97 (0.89–1.00) (61/63)
CTA+MRA<3 mm0.20 (0.04–0.48) (3/15)0.98 (0.91–1.00) (61/62)
(34 “uncertain”)3–5 mm0.50 (0.31–0.69) (15/30)1.00 (0.94–1.00) (61/61)
5.1–10 mm0.89 (0.52–1.00) (8/9)1.00 (0.94–1.00) (61/61)
>10 mm1.00 (0.69–1.00) (10/10)1.00 (0.94–1.00) (61/61)
All0.56 (0.43–0.69) (36/64)0.98 (0.91–1.00) (61/62)
  • “Uncertain” indicates that the tests disagreed about the presence of an aneurysm.

  • 3-150 For TCD, size categorisation was not available for all the false positive cases, therefore specificity and accuracy could not be determined by aneurysm size category.