What is BOM?

In a word, it is a value that represents the resistivity of blood flow. The higher the BOM, the higher the resistivity.

BOM (BS Over MBR) does not require an average waveform of one heartbeat like BOS and other parameters, so it can measure resistivity even in blood flow waveforms with arrhythmia. In this regard, compared to other waveform parameters, values are easier to obtain, making it a clinically suitable resistivity parameter.

Clinical applications include observation of BRVO¹ and age-related hemodynamic changes².

- Application in BRVO

The maps below are excerpts from a paper¹ reporting a BRVO case. The left side shows the blood flow map and the right side shows the resistivity (BOM) map.

The red areas in the BOM map on the right side are regions with high resistivity, and it can be confirmed that resistivity is elevated (blue arrow) due to vascular stenosis.

- Age-related hemodynamic changes

The maps below are also excerpts from a paper². They show the blood flow maps (left side) of the same subject and their corresponding resistivity (BOM) maps (right side).

There is an 8-year difference between the upper and lower rows. While the blood flow maps show little change, the resistivity maps show an increase in red areas with aging, confirming that resistivity has increased due to arteriosclerosis.

For detailed calculation methods of BOM, please refer to the paper² and patent³.

Recent reports

1. Ryo Tomita, Takeshi Iwase, Marie Fukami, Kensuke Goto, Eimei Ra and Hiroko Terasaki
   Elevated retinal artery vascular resistance determined by novel visualized technique of laser speckle flowgraphy in branch retinal vein occlusion
   Scientific Reports, 11(1), 1-11, 10.1038/s41598-021-99572-7, 2021
2. Kenji Okamoto, Noriyoshi Takahashi, Tatsuhiko Kobayashi, Tomoaki Shiba, Yuichi Hori and Hitoshi Fujii
   Novel superpixel method to visualize fundus blood flow resistivity in healthy adults
   Scientific Reports, 13, doi:10.1038/s41598-023-33450-2, 2023.
3. FUJII, H. et al. Blood Flow Dynamic Imaging Diagnosis Device and Diagnosis Method. https://patentscope2.wipo.int/search/en/detail.jsf?docId=WO2018003139 (2018).