{'fraction_non_alphanumeric': 0.01997780244173141, 'fraction_numerical': 0.004439511653718091, 'mean_word_length': 5.632352941176471, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Ultrasonographic modalities to assess vascular anatomy and disease.

Medical ultrasound (US) encompasses a family of imaging techniques linked by the use of high-frequency sound waves, typically 2.5-10 million cycles per second (MHz), to interrogate tissue. Although similar, each imaging technique has relatively distinct features and may provide unique information. This review is designed to provide vascular and interventional radiologists with an in-depth understanding of each US imaging technique and relevant physics principles to assist in optimizing the US examination so that the specific vascular anatomy and disease states in question can be comprehensively understood. This review will be limited to principles of transcutaneous US and will not include specific techniques for assessment of individual vessels (except for illustrative purposes) or methods to optimize US scan parameters.