サイレント磁気共鳴血管造影：神経血管イメージングの技術と応用

Silent Magnetic Resonance Angiography (S-MRA) is a non-contrast MR imaging method that utilises ultrashort echo in conjunction with the arterial spin labeling technique to produce angiographic images. The present article discusses the technical aspects of Silent MR angiography and its applications in neurovascular imaging, along with its advantages and pitfalls.

Using illustrative cases, various applications of the Silent MRA are explored along with a brief discussion on its technique and limitations. The Silent MR sequence provides an angiographic image with good background suppression in a duration of about 6-7 min and is devoid of saturation artefacts seen with Time of Flight (TOF) MR angiography.

Applications include assessment of aneurysms (both untreated and treated cases), direct and indirect carotico-cavernous fistulas, dural arteriovenous fistulas, intracranial atherosclerotic disease, and Moya Moya disease with superior image quality compared to MR TOF angiography. It is particularly useful in post-procedural scans, such as after stenting and flow diverter placement, owing to reduced artefacts. In the pediatric population and acutely ill patients, an additional advantage includes reduced acoustic noise during the sequence, leading to diminished requirements for repeat studies.

S-MRA is a useful non-contrast MR angiography technique with improved image quality and reduced artifacts compared to MR TOF angiography, thereby facilitating the evaluation of multiple neurovascular diseases both pre- and post-interventions.