ABC | Volume 112, Nº6, June 2019

Statement Vascular Ultrasound Statement from the Department of Cardiovascular Imaging of the Brazilian Society of Cardiology – 2019 Arq Bras Cardiol. 2019; 112(6):809-849 *Table 26 – Vasospasm classification Artery: MCA MFV (cm/s) Lindegaard ratio Mild 120 to 130 3 to 6 Moderate 130 to 200 3 to 6 Severe > 200 > 6 Artery: ACA > 50% of MFV in 24h – Artery: PCA > 110 – Artery: VA > 80 – Artery: basilar Soustiel ratio Mild 80 to 95 2 to 2.49 Moderate > 85 2.5 to 2.99 Severe > 115 > 3 MCA: middle cerebral artery; ACA: anterior cerebral artery; PCA: posterior cerebral artery; VA: vertebral artery. Note: Lindegaard ratio is the ratio between the highest mean flow velocity (MFV) in the middle cerebral artery (M1) and MFV in the ipsilateral extracranial internal carotid. Soustiel ratio is the ratio between vertebral MFV and basilar MFV. ****Table 27 – Recommendations of the Brazilian Guidelines for Transcranial Doppler in Children and adolescents with Sickle Cell Disease (2010) 123 Mean flow velocity CVA risk group Approach Inadequate ultrasonic windows Inconclusive Use another imaging method to assess cerebrovascular events Difficult execution: uncooperative patient Inconclusive Repeat in 3 months, with a different examiner if possible < 70 cm/s Low flow Repeat the examination in 30 days < 170 cm/s Normal Repeat the examination in 12 months 170 to 184 cm/s "Low conditional" Repeat the examination in 3 months: if < 170 cm/s, repeat in 12 months 184 to 199 cm/s "High conditional" Repeat the examination in 30 days: if < 170 cm/s, repeat TCD every 3 months; if two consecutive examinations are abnormal, consider long-term blood exchange 200 to 220 cm/s Abnormal Repeat the examination in 30 days: if > 200 cm/s, blood exchange; if "high conditional", repeat TCD in 3 months; if "low conditional", repeat it in 6 months > 220 cm/s Abnormal Imminent risk of CVA, consider long-term blood exchange CVA: cerebrovascular accident; TCD: transcranial Doppler. - Pulsed wave Doppler – laminar or turbulent pattern, direction (antegrade or retrograde), velocities of spectral flow curves (peak systolic, end-diastolic, and mean), and PI and resistance according to the clinical indication of the examination (e.g., sickle cell disease requires mean velocity). - Contrast solution with “macrobubbles” – record and count of HITS in the study of patent foramen ovale and paradoxical embolism. - Use of contrast agent with “microbubbles” (SonoVue®). - In the intraoperative monitoring, report the occurrence and count of HITS/hour and variations in flow velocities with potential risk for ischemic CVA in the postoperative period. Conclusion : avoid etiological diagnosis (TCD is a study of cerebral hemodynamics and findings should be correlated to the clinical indication of examination: for instance, the presence or lack of criteria for vasospasm, with grade classification and time reference to the onset of symptoms of subarachnoid hemorrhage). Note : in cases of sickle cell disease, it is mandatory to specify, after the conclusion, the recommended date to repeat the reassessment examination (following the Brazilian Guidelines for Transcranial Doppler in Children and Adolescents with Sickle Cell Disease, 2010). 123 In other pathologies, this suggestion is prohibited due to professional ethics. 8. Contrast in Vascular Ultrasound The introduction of contrast agents in ultrasound examinations considerably expanded the clinical value of this method. B-scan ultrasound is an excellent method to demonstrate the anatomical and morphological characteristics of parenchymal tissue but does not provide any information about the viability and integrity of microcirculation. Color Doppler ultrasound (CDUS) added data about blood flow velocity but is not able to quantify the volume and show with enough sensitivity the blood flow in microcirculation, 124-126 where velocity is too low to be detected without artifacts created by tissue and transducer maneuvers. Also, the spatial resolution of CDUS is limited, the representation of velocity is angle-dependent, and numerous artifacts can influence the diagnostic interpretation of images. Contrast-enhanced Doppler ultrasound substantially increased the sensitivity of CDUS and reduced some limitations. The technical innovation was the introduction of specific image components for contrast in US equipment, allowing direct visualization of signals emitted by microbubble contrast agents, regardless of their velocities. Due to typical characteristics of microbubble signals (which are fundamentally different from those originating in tissues), “specific microbubble” images (contrast only) are created, which can show volume and perfusion of the parenchymal tissue with extremely high sensitivity and spatial resolution. 124 841