Transcranial Doppler (TCD) is a non-invasive procedure that is increasingly used for diagnostic and prognostic purposes in patients with an acute stroke. In addition, TCD enhances the effect of thrombolysis by exposing thrombi surfaces to circulating rTPA. However, insonation problems through acoustic windows limit the diagnostic efficiency of TCD.
Transcranial Doppler
Temporal Squama Pneumatization: An Under-Recognized Limitation Of Transcranial Doppler. Pneumatización de las Escamas Temporales: Una Limitación Poco Reconocida Del Doppler Transcraneal
Keywords: pneumatization,
Transcranial Doppler,
Fístula Carótido Cavernosa. Utilidad del ultrasonido Doppler en el diagnóstico. Cavernous carotid fistula. Utility of Doppler ultrasound in diagnosis.
Introduction. Carotid cavernous fistulas are infrequent vascular malformations that generate a pathological arteriovenous shunt, which compromises ocular function. The definitive diagnosis is established by cerebral arteriography. However, its invasive nature limits its use in follow-up. The aim of this work is to illustrate the value of the study with transcranial doppler ultrasound for the diagnosis of cavernous carotid fistulas and to describe the flow parameters that could be modified. Patients. A retrospective review of the clinical histories of the patients treated with a diagnosis of cavernous carotid fistula was carried out in the stroke unit of the Hermanos Ameijeiras Hospital in Havana, between January 2005 and May 2014. Demographic and disease variables were collected, as well as the results of imaging and ultrasound studies. Results. We describe the clinical and imaging characteristics of three patients in whom carotid cavernous fistula was confirmed. In the two patients with direct communications, an increase of the mean flow velocity in the ophthalmic vein, arterialized, with decrease in pulsatility were registered; in addition to an increase in the diastolic peak velocity in the internal carotid artery ipsilateral to the fistula. In the patient with the indirect fistula the changes were less marked. Conclusion. The ultrasound study was useful in the diagnosis of carotid cavernous fistulas, showing differences in the flow parameters that can be used to classify the fistulas.
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Palabras clave: Doppler transcraneal,
Fistula arteriovenosa dural,
Fistula carótido cavernosa,
Ictus,
ultrasonido,
Índice de Pulsatilidad Cerebral en Adultos Mayores con Infarto Lacunar Silente (Proyecto Atahualpa). Cerebral Pulsatility Index In Older Adults With Silent Lacunar Strokes (The Atahualpa Project).
Background: Diagnosis of silent lacunar infarcts is complicated in remote rural areas where MRI is not available. Hospital series have suggested an association between the pulsatility index of intracranial arteries –as assessed by transcranial Doppler –and some neuroimaging signatures of cerebral small vessel disease. We aimed to assess the reliability of cerebral pulsatility indices to identify candidates for MRI screening in population-based studies assessing prevalence of silent lacunar infarctions.
Methods: A random sample of stroke-free Atahualpa residents aged ≥60 years investigated with MRI underwent transcranial Doppler for calculating the pulsatility index (PI) of the middle cerebral artery (MCA). For each person, mean PI was obtained by averaging both MCAs. Using conditional logistic regression for matched pairs data, we evaluated whether the pulsatility index of both MCAs correlate with silent lacunar infarcts.
Results: Silent lacunar infarcts were noticed in 28 (12%) of 234 scanned persons. Six of them were excluded due to poor insonation through transtemporal windows. The remaining 22 participants were considered case-patients and were matched 1:1 with individuals free of infarcts (controls). Moderate-to-severe white matter hyperintensities were noticed in 12 (55%) case-patients and 7 (32%) controls (p=0.228). The mean MCA PI value in the 44 participants was 1.15 ± 0.21, with no difference found across case-patients and controls, after adjustment for white matter hyperintensities (β coefficient: 3.361, 95% C.I.: -0.693 to 7.417, p=0.104).
Conclusions: Cerebral PI should not be used to identify candidates for MRI screening in population-based studies assessing the burden of silent lacunar infarcts.
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Búsqueda de Substitutos Para Estudios de Neuroimagen con Propósitos de Investigación: Experiencia del Proyecto Atahualpa. The Search Of Surrogates For Neuroimaging Studies For Research Purposes: The Atahualpa Project Experience
Diagnosis of many non-communicable neurological diseases require the use of MRI, which is not readily available in remote rural populations. Efforts should be directed to find portable screening diagnostic tools that may help identify candidates for MRI screening. In the Atahualpa Project, all participants aged ≥60 years have been invited for the practice of MRI, and about 80% of them have underwent the procedure. Therefore, we have the unique opportunity to test the accuracy of non-invasive exams to be used as surrogates to MRI for identifying candidates for the practice of this exam. To date, we have assessed the value of the ankle-brachial index (ABI), the reliability of the neutrophil-to-lymphocyte ratio (NLR), the accuracy of hypertensive retinopathy, and the value of transcranial Doppler (TCD) to detect individuals with cerebral small vessel disease. Individuals with an abnormal ABI have 4 times de odds of having a silent lacunar infarct than those with a normal ABI. A high NLR has a poor sensitivity but is highly specific for detecting persons with at least one imaging signature of small vessel disease. Individuals with hypertensive retinopathy Grades 2-3 are almost four times more likely to have moderate-to-severe white matter hyperintensities than those with no- or only Grade 1 retinopathy. Finally, the correlation between the pulsatility indexes of major cerebral arteries with imaging markers of small vessel disease, as assessed by TCD, was poor. We are still in the search of some non-expensive and readily available biomarker that allow the identification of apparently healthy persons at risk of suffering a catastrophic cerebrovascular event.
