Standing waves are not distinctive to conventional angiograms

First International Consensus on the diagnosis and management of fibromuscular dysplasia

“…The differential diagnosis of FMD is broad, and includes many other arterial pathologies as well as imaging artifacts. [46][47][48][49][50][51][52][53][54][55][56][57][58] The imaging diagnosis depends upon the finding of typical patterns of FMD (focal or multifocal lesions) as well as the presence of associated arterial findings (dissection, aneurysm, and tortuosity). Table 3 reviews key elements of the differential diagnosis of FMD.…”

“…Entities that may be confused with multifocal FMD Systemic arterial mediolysis (SAM) 46 • Non-inflammatory, non-atherosclerotic disease • Manifests as spontaneous arterial dissection, rupture, occlusion, or aneurysm, most often in the abdominal visceral arteries • May be indistinct from multifocal FMD on angiographic imaging • Definitive diagnosis requires histopathological examination demonstrating vacuolar degeneration of the artery media Arterial spasm Standing waves 57,58 • Benign radiologic findings due to vasospasm such as those induced by ergotamine derivatives or sympathomimetic drugs or catheter-related vasospasm • Transient flow-related physiologic changes in the artery resulting in regular oscillations distinct from multifocal FMD (beading of varying size) • Neither entity requires further evaluation or follow-up when identified Imaging artifacts…”

“…With the support of the FMD Association of Australasia, a very active patient advocacy group (http:// www.fmdaa.org.au/), 41 patients have been enrolled as of February 2018. 57,58 • Benign radiologic findings due to vasospasm such as those induced by ergotamine derivatives or sympathomimetic drugs or catheter-related vasospasm • Transient flow-related physiologic changes in the artery resulting in regular oscillations distinct from multifocal FMD (beading of varying size) • Neither entity requires further evaluation or follow-up when identified Imaging artifacts…”

FMD and SCAD: Sex-Biased Arterial Diseases With Clinical and Genetic Pleiotropy

“…1,3 Angiographic mimickers of FMD, including healing dissection or imaging-induced vasospasm resulting in the appearance of an artificially regular string-of-beads appearance (standing waves), may result in clinical confusion. 50,51…”