Article Figures & Data
Figures
- Fig 1.
Receiver operating characteristic curves show the diagnostic performance of the incremental CT protocol in the detection of lacunar infarction, without adjusting for multiple readers. There is a statistically significant increase in the area under the curve with each incremental protocol (CTP versus CTA, P < .006, and CTP versus NCCT, P < .001). The dashed line indicates NCCT only; the dotted line, NCCT and CTA-SI; and the solid line, NCCT, CTA-SI, and CTP.
- Fig 2.
Images of a 72-year-old man who presented with left-sided weakness (NIHSS score, 9), scanned 85 minutes after symptom onset. NCCT (A) and CTA-SI (B) show subtle hypoattenuation, inconclusive for acute infarction (white arrows). C, The MTT map demonstrates a perfusion deficit in the right lentiform nucleus (black arrow). The patient received intravenous thrombolysis. D, Follow-up DWI confirms lacunar infarction in the right lentiform nucleus (white arrow).
- Fig 3.
Images of a 55-year-old man who presented with left-sided weakness. A, No abnormality is evident on NCCT. B, CTA-SI shows a possible hypoattenuation in the posterior limb of the right internal capsule or thalamus. C, MTT map demonstrates a focus of increased MTT in the region of the internal capsule (black arrow). The patient received intravenous thrombolysis. D, Follow-up DWI confirms focal hyperintensity consistent with recent lacunar infarction in the posterior limb of the right internal capsule (white arrow).
Tables
- Table 1:
Comparison of baseline demographic features of 88 patients presenting with acute stroke symptoms with and without lacunar infarcta
Lacunar Infarct Present (n = 59) Lacunar Infarct Absent (n = 29) P Value Mean age (yr) (SD) 72 (13.4) 68 (17.5) .30 Median NIHSS (IQR) 6.5 (5) 2 (5) .16 Median days to follow-up (IQR) 2.5 (3) 2 (5.5) .60 Male sex 33 (56%) 11 (38%) .17 Cardiovascular risk factors Hypertension 39 (66%) 12 (41%) .04b Diabetes 15 (25%) 1 (3%) .02b Atrial fibrillation 8 (14%) 1 (3%) .26 Coronary artery disease 13 (22%) 4 (14%) .40 Hyperlipidemia 23 (39%) 6 (21%) .10 Smoking 6 (10%) 1 (3%) .27 - Table 2:
Distribution of confidence scores for infarct presence by modality for 2 readers for a total of 352 observations
Confidence Score NCCT NCCT + CTA-SI NCCT + CTA-SI + CTP 1 Definitely present 5 (1.4%) 16 (4.5%) 42 (11.9%) 2 Probably present 25 (7.1%) 26 (7.4%) 27 (7.7%) 3 Equivocal, possibly present 83 (23.6%) 68 (19.3%) 18 (5.1%) 4 Equivocal, possibly absent 4 (1.1%) 2 (0.6%) 18 (5.1%) 5 Probably absent 78 (22.2%) 89 (25.3%) 131 (37.2%) 6 Definitely absent 157 (44.6%) 151 (42.9%) 116 (33.0%) - Table 3:
Progressive increase of multiple entropy r2 value and decrease of AIC with the incremental protocola
Logistic Regression Model GEEs Method r2 AIC P Value Odds Ratio (95% CI) AIC P Value NCCT Model fit statistics 0.015 451.1 451.3 Observed diagnosis (yes vs no) .28 1.68 (0.65–4.41) .29 Observed confidence score .90 1.03 (0.67–1.58) .90 NCCT + CTA-SI Model fit statistics 0.170 409.2 408.7 Observed diagnosis (yes vs no) .59 0.78 (0.31–1.94) .57 Observed confidence score <.001b 0.46 (0.31–0.68) <.001b NCCT + CTA-SI + CTP Model fit statistics 0.329 357.3 357.1 Observed diagnosis (yes vs no) .04b 0.33 (0.11–0.95) .05 Observed confidence score <.001b 0.30 (0.20–0.44) <.001b Note:—GEEs indicates generalized estimating equations.
↵a With logistic regression analysis and the GEEs method, the actual stroke diagnosis was modelled on different observed diagnoses (NCCT alone, NCCT + CTA-SI, NCCT + CTA-SI + CTP) when adjusting for the corresponding confidence score. OR < 1 indicates that patients with a positive diagnosis on MRI are more likely to have a lower level of confidence (1 = definitely present, 2 = probably present, 3 = possibly present, 4 = possibly absent, 5 = probably absent, 6 = definitely absent).
↵b Statistically significant.
- Table 4:
Diagnostic performance for stroke detection with incremental study review using receiver operating characteristic–determined thresholds for level of confidence
Sensitivity Specificity Se% (95% CI) P Valuea Sp% (95% CI) P Valuea Level of confidence ≥5 vs <5 1) NCCT 40.7 (30.8–50.6) 1 vs 2: .174 70.5 (64.4–76.7) 1 vs 2: .088 2) NCCT + CTA-SI 51.7 (40.9–62.5) 1 vs 3: .048b 78.2 (72.2–84.2) 1 vs 3: .002b 3) NCCT + CTA-SI + CTP 55.9 (45.6–66.3) 2 vs 3: .536 83.3 (78.3–88.3) 2 vs 3: .155 Level of confidence ≤2 vs <2 1) NCCT 9.3 (4.3–14.3) 1 vs 2: .009b 91.9 (88.5–95.2) 1 vs 2: .130 2) NCCT + CTA-SI 26.3 (17.3–35.3) 1 vs 3: <.001b 95.3 (92.5–98.1) 1 vs 3: .691 3) NCCT + CTA-SI + CTP 42.4 (30.6–54.2) 2 vs 3: .030b 91.9 (88.4–95.4) 2 vs 3: .264 - Table 5:
Interobserver variability between 2 readers for lacunar infarction detection with incremental protocol
Cohen κ (95% CI) for Each Sequence NCCT NCCT + CTA-SI NCCT + CTA-SI + CTP Reader 1 vs 2 0.25 (0.11–0.39) 0.47 (0.34–0.61) 0.50 (0.35–0.64)
