Diagnostic accuracy of whole-brain computed tomographic perfusion imaging in small-volume infarctions

The aims of this study were to determine the diagnostic accuracy of whole-brain computed tomographic perfusion (WB-CTP) in small ischemic brain infarctions and to identify factors influencing the detection rate.

Out of a retrospective cohort of 1380 subjects who underwent initial WB-CTP because of suspected stroke, we selected all patients with a supratentorial magnetic resonance imaging-confirmed ischemic infarction with a volume of 8 mL or less. Infratentorial lesions were excluded. The study was designed as a case-control study with a ratio of cases to controls with no infarction in follow-up magnetic resonance imaging of 1:3. Two blinded readers independently evaluated 4 different computed tomographic perfusion parameter data sets per subject with respect to the presence and localization of a perfusion deficit.

A total of 113 subjects met the inclusion criteria for the patient group. Overall, WB-CTP reached a sensitivity of 43.4% and a specificity of 92.9%. Among these, cortical infarctions were detected in 31 (69%) of 49 cases, whereas subcortical infarctions were detected only in 18 (28%) of 64 cases (P < 0.05). Mean final infarction diameter (17.3 mm) and volume (1.9 mL) of infarctions detected on CTP were significantly larger than those of infarctions not detected (12.4 mm and 0.8 mL, respectively; P < 0.001). Time from symptom onset did not differ significantly between infarctions that were detected or those that were not (204 vs 189 minutes; P = 0.75).

The detection rate of WB-CTP in small infarctions highly depends on infarction localization and final size, whereas time from symptom onset does not seem to influence diagnostic accuracy.