Association between Tomographic Characteristics of the Temporal Bone and Transtemporal Window Quality on Transcranial Color Doppler Ultrasound in Patients with Stroke or Transient Ischemic Attack.

Transcranial color-coded Doppler (TCCD) is an ultrasonographic technique used to obtain and evaluate images of the cerebral parenchyma and to assess blood flow velocities of the intracranial vessels. One of the major limitations of TCCD is the failure to insonate through the transtemporal window, which occurs in about 5%-44% of patients. Temporal bone thickness has been strongly associated with transtemporal window failure (TWF). The aims of the study were to evaluate the association between TWF on TCCD and radiologic findings on computed tomography of the skull along with the demographic characteristics of patients with acute stroke or transient ischemic attack (TIA), and to propose a classification for transcranial window quality (TWQ) on B-mode scan of TCCD. A total of 187 consecutive patients with acute stroke or TIA were included. Among them, 21.9% had TWF and 34.8% had TWQ categorized as insufficient on B-mode scan of TCCD. On logistic regression, age (odds ratio [OR] = 1.07, 95% confidence interval [CI]: 1.03-1.12, p < 0.001), female sex (OR = 5.99, 95% CI: 2.09-17.16, p = 0.001), pneumatized temporal bone (OR = 7.90, 95% CI: 1.95-32.03, p = 0.004) and temporal bone thickness (OR = 3.04, 95% CI: 1.73-5.35, p < 0.001) were independent predictors of TWF, even after adjusting for confounders. These findings may help to select patients in whom echogenic contrast or even other imaging methods could be used to assess intracranial vessels.