To display

the plane at midbrain level, the examination starts with the identification of the hypo- to anechogenic butterfly-shaped structure of mesencephalic brainstem surrounded by the highly echogenic basal cisterns in the axial scanning plane. PTC124 order The mesencephalic brainstem surrounded by the highly echogenic basal cisterns can easily be delineated in 90–95% of individuals, even in those with only partially sufficient acoustic bone windows. Within the brainstem, several structures of increased echogenicity, including SN, red nucleus, the midline raphe, and the aqueduct can be visualized. For the clinical applications described in this article, the assessment of SN echogenicity is most important. To date, the best-validated method to grade SN echogenicity is the planimetric measurement of SNs echogenic signals in axial plane [1], [2] and [20]. Semiquantitative visual Y-27632 ic50 grading was less reliable [20] and [21]. Efforts to quantify SN echogenicity in a less rater-dependent way, e.g., by measuring echointensity of SN relative to surrounding

parenchyma, volumetry, semi-automatic SN detection, or complex mathematical echo-signal analysis have either failed, or are not ripe for clinical application [20]. According to consensus guidelines [1], a marked SN hyperechogenicity is considered, if the measured

echogenic area exceeds a cut-off value defined by the 90% percentile of measures in normal population, and moderate hyperechogenicity, if the measured area ranges Urease in-between the 75% and 90% percentile of measures in normal population. Most authors use the larger of bilaterally measured sizes for rating SN echogenicity. Hitherto, standard reference values on echogenic sizes of the SN have been published for a number of ultrasound systems as listed in Table 2[14], [21], [22], [23], [24], [25], [26], [27] and [28]. To display the plane at thalamus level the ultrasound probe is tilted 10–20° in upward direction. An important landmark of the thalamus level is the usually calcified, and therefore highly echogenic pineal gland (Fig. 3). At this plane, the third ventricle, anterior horns of the lateral ventricles, the thalami and the anatomic site of the basal ganglia are depicted. The thalami are typically displayed as hypoechogenic oval structures; the thalami and the frontal horns help to discern the anatomical site of caudate nucleus and lenticular nucleus. At this level, the transverse diameters of the third ventricle, and of the frontal horn of the contralateral lateral ventricle can be measured [1] and [11]. Hydrocephalus can be easily diagnosed on TCS.