Ultraschall Med 2023; 44(05): 460-466
DOI: 10.1055/a-2143-7233
Editorial

Novel ultrasonic imaging of the brain and its vasculature: the long way to clinical guideline recommendation

Article in several languages: English | deutsch
Uwe Walter

The classical ultrasound modalities used nowadays in clinical routine for imaging of the brain and its vasculature were pioneered in the 1960s (B-mode) and 1980s (color Doppler) [1] [2] [3] [4] [5] [6] [7], however, became part of clinical standard recommendations and guidelines not before the late 1990s [8] [9] [10] [11] [12]. An important reason for the delay in transferring transcranial B-mode sonography (TCS) and transcranial color-coded duplex sonography (TCCS) into clinical routine was the competition with the in-parallel evolving CT and MRI techniques that enable complete brain and (static) vasculature scans in short time and highly reproducible manner, unlike transcranial ultrasound [13]. The limitation of ultrasound image quality by the cranial bone accounted for the relatively long dominance of one-dimensional echo-encephalography (A-scan) over two-dimensional (B-mode) scan, and of conventional transcranial Doppler sonography over TCCS, despite their early availability and comparative evaluation [14] [15] [16]. This is different in infants in whom the intracranial structures can be visualized ultrasonically with high image resolution through open fontanelles, allowing even for the assessment of cerebral cortex and bridging veins as is elegantly demonstrated using a 14-MHz transducer in the case reported by K.H. Deeg in the present issue of Ultraschall in der Medizin [17]. Also, cranial bone surface can well be assessed with high-frequency ultrasound, as is nicely shown using a 11-MHz transducer in the study of Pogliani et al. (this issue) [18]. Transcranial sonography, however, requires lower ultrasound frequencies of around 2.5 MHz in adolescents and adults to penetrate the bone which limits image resolution. Despite this drawback, image resolution on TCS reached a remarkable level already in the 2000s thanks to technological advances, allowing for relatively high resolution of echogenic deep brain structures in the focal zone of transducer [19]. The recent boom of therapeutic transcranial focused ultrasound (tFUS), applied e. g. for the treatment of essential tremor, has boosted the efforts in individualized optimization of transcranial ultrasound penetration which may also benefit the diagnostic TCS and TCCS technologies in near future [20].



Publication History

Article published online:
13 October 2023

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