Keywords:
Ischaemia / Infarction, Comparative studies, Image manipulation / Reconstruction, CT, Head and neck, Emergency
Authors:
K. A. R. Balalta; Dasmarinas city/PH
DOI:
10.26044/ecr2019/C-2422
Results
Accuracy rate is the percentage of correct detection over total number of patients.
"Stroke windows" was able to detect 92% correctly,
with "brain windows" only detecting 68%. Fig. 9
Sensitivity for "stroke windows" is 86.67% (75.41% to 94.06%),
while for "brain windows" is 46.67% (33.67% to 60.00%) - stroke detection is more sensitive using "stroke windows" than "brain windows".
Specificity for both "stroke windows" and "brain windows" is 100% (91.19% to 100.00%) - both are equal in identifying the absence of hyperacute infarction.
Positive predictive value for both "stroke windows" and "brain windows" is 100% (93.15% to 100.00% and 87.66% to 100.00%,
respectively).
By looking at the 95% confidence interval,
the probability is higher on "stroke windows" than "brain windows".
Negative predictive value for "stroke windows" is 83.33% (69.78% to 92.52%) while for "brain windows" is 55.56% (43.36% to 67.28%).
Therefore,
null findings of "stroke windows" are more reflective of the outcome than "brain windows."
Area under the curve is the magnitude of how well "stroke windows" or "brain windows" detect hyperacute infarction.
The AUC coefficient is higher for "stroke windows" than "brain windows."
|
Presence of Stroke
|
Sensitivity
|
Specificity
|
PPV
|
NPV
|
AUC
|
Accuracy
|
|
Yes
|
No
|
Stroke Window
|
Present
|
52
|
0
|
86.67% (75.41% to 94.06%)
|
100% (91.19% to 100.00%)
|
100% (93.15% to 100.00%)
|
83.33% (69.78% to 92.52%)
|
0.930
|
92.0%
|
Absent
|
8
|
40
|
Brain Window
|
Present
|
28
|
0
|
46.67% (33.67% to 60.00%)
|
100% (91.19% to 100.00%)
|
100% (87.66% to 100.00%)
|
55.56% (43.36% to 67.28%)
|
0.730
|
68.0%
|
Absent
|
32
|
40
|
Table 1.
Sensitivity,
Specificity,
and Diagnostic Accuracy of “stroke windows” compared to "brain windows".
|
Agreement
|
95% Confidence Interval
|
Stroke
|
0.916
|
0.883 to 0.941
|
Brain
|
0.911
|
0.876 to 0.938
|
Table 2. Agreement test on hyperacute infarct detection for the three radiologists. A coefficient greater than 0.900 is indicative of excellent agreement,
therefore the detection done by three radiologists on both "brain windows" and "stroke windows" were statistically similar.
|
Total Number Of Head CT Scan
|
Hyperacute Infarction
|
Prevalence Of Hyperacute Infarction
|
Prevalence Of Hyperacute Infarction,
2015-2017
|
2015
|
2966
|
18
|
0.61%
|
0.69%
|
2016
|
2702
|
32
|
1.18%
|
2017
|
2880
|
9
|
0.31%
|
Table 3.
Prevalence of hyperacute infarction for the years 2015-2017.
Fig. 8