Table 6. Top 10 clusters of keywords in 4D flow MRI from 2003 to 2022.

Cluster ID	Size	Silhouette value	Mean year	Cluster label	Label (LLR)
0	38	0.845	2012	Magnetic resonance imaging	Magnetic resonance imaging; wall shear stress; phase contrast; bicuspid aortic valve; geometry
1	38	0.901	2014	Cerebral aneurysm	Cerebral aneurysm; computational fluid dynamics; intracranial aneurysm; intracranial aneurysms; relative residence time
2	34	0.682	2014	Management	Management; thoracic aorta; fetal; patient-specific heat map; automatic labeling
3	31	0.858	2018	Portal hypertension	Portal hypertension; cirrhosis; aortic disease; relative pressure; portal vein
4	30	0.802	2017	Diastolic function	Diastolic function; heart failure; flow components; 3d cine; human left ventricle
5	29	0.926	2014	Resolution	Resolution; aneurysm; abdominal aortic aneurysm; volunteer; reconstruction
6	27	0.866	2017	Kinetic energy	Kinetic energy; atrial fibrillation; cardiac MRI; stasis; left ventricle
7	27	0.941	2014	4D flow	4D flow; Alzheimer’s disease; middle cerebral artery; pulsatility index; 4D flow CMR
8	26	0.913	2012	Cardiac magnetic resonance	Cardiac magnetic resonance; cerebrospinal fluid; syringomyelia; Chiari malformation; Marfan syndrome
9	22	0.873	2017	Cerebrovascular hemodynamics	Cerebrovascular hemodynamics; aortic hemodynamics; patient-specific simulation; computational fluid dynamics; image-based modeling

4D flow MRI, 4-dimensional flow magnetic resonance imaging; LLR, log-likelihood ratio; CMR, cardiovascular magnetic resonance.