Accuracy of Diffusion-Weighted Imaging in the Diagnosis of Stroke in Patients With Suspected Cerebral Infarct

Abstract

Background and Purpose— The accuracy of diffusion-weighted imaging (DWI) for the diagnosis of acute cerebral ischemia among patients with suspected ischemic stroke arriving to an emergency room has not been studied in depth. Methods— DWI was performed in 712 patients with acute or subacute focal symptoms that suggested an acute ischemic stroke (AIS), 609 of them with AIS. Results— DWI demonstrated a sensitivity of 90% and specificity of 97%, a positive likelihood ratio of 31 and a negative likelihood ratio of 0.1 for detecting AIS. The overall accuracy was 95%. Of those patients who demonstrated abnormal DWI studies, 99.5% were AIS patients, and of those patients with normal DWI studies 63% were stroke mimics. Conclusions— DWI is accurate in detecting AIS in unselected patients with suspected AIS; a negative study should alert for nonischemic conditions.

Sensitivity of Diffusion- and Perfusion-Weighted Imaging for Diagnosing Acute Ischemic Stroke Is 97.5%

“…In agreement with our findings, a previous study found a sensitivity of 90.4% of DWI on stroke diagnosis, 6 and a smaller study found a false-negative rate of 5.8% when imaging was performed within 48 hours. 7 Another study was using MRI and showed negative DWI in 33% of patients, but these patients were scanned with a median time of 12 days after the symptom onset and had mild strokes with a median National Institute of Health Stroke Scale of 2, so it is not comparable with our study.…”

“…14 The finding emphasizes that if DWI is to be used in mild strokes, it is important to do imaging acutely, as it is done for transient ischemic attacks. 14,15 In line with Brunser et al, 6 our study shows that DWI MRI has a sensitivity of >90% when applied acutely, and we found a sensitivity of ≈100% when information from the PWI was added. Smallvessel disease was seen more prevalent among the DWI negative patients.…”

“…[3][4][5] However, DWI can occasionally be negative in acute ischemic stroke. 6,7 We aimed to determine whether perfusionweighted imaging (PWI) provides further diagnostic information to the evaluation of patients with ischemic stroke who were DWI negative.…”

Trombolisis intravenosa en cuadros imitadores de isquemia cerebral: experiencia de un centro

“…Considerando la baja frecuencia con la que pacientes con CIMIC reciben terapia de TIV, junto con su riesgo hemorrágico bajo y, por otra parte, tomando en cuenta de que claramente los pacientes ACVi se benefician de este tratamiento que es tiempo dependiente 3 , nuestra opinión es que debe privilegiarse en los servicios de urgencia la reducción del tiempo puerta aguja, por sobre tener un diagnóstico 100% definitivo y con imá-genes de la presencia de un ACVi, debido a que esta acuciosidad diagnóstica con neuroimágenes puede además no lograrse en todos los pacientes 12 . Nuestro estudio posee fortalezas al tratarse de un registro prospectivo de pacientes consecutivos en un ambiente clínico habitual y con un número significativo de enfermos consultantes y también con alta frecuencia de administración de TIV.…”

“…Aquellos pacientes que, pese a imáge-nes cerebrales y vasculares normales, presentaban un altamente probable síndrome neurovascular, sin otro diagnóstico alternativo de urgencia, fueron catalogados como ACVi 12 . El diagnóstico de CIMIC se realizó basado en la presencia de déficit focales neurológicos agudos, que pudieran ser explicados en forma categórica por un cuadro médico distinto a un ACVi y el diagnóstico de isquemia cerebral descartado 12 .…”