One of the reasons they don't give people CAC tests generally unless their risk is super high, at least in most countries, is because they might get a score of zero and then think they are safe and go on ignoring their doctor's advice. Studies showed that if you are low risk for other reasons, CAC 0 subjects have low chance of events. If you are high risk by other measures, CAC 0 subjects still have a high risk of cardiac events in the near term. So the whole CAC scoring thing is discredited as not adding any additional value beyond the other biomarkers. Bayes Theorem applies here. If pretest risk was high, a score of 0 does not mean you have low chance of a heart event - it simply doesn't supercede the priors. Anyhow that's what this study says: https://www.ahajournals.org/doi/full/10.1161/CIRCULATIONAHA.108.767665

Also, lots of research that ApoB levels are strongly positively associated with atherosclerosis progression. A lot of keto people (not all of them) have high LDLs which are representative (but not a perfect measure) of ApoB (which they unfortunately rarely test directly). Huge amounts of study and research went into determining this, that it was ApoB coorelated, not triglyceride or blood sugar coorelated (for example). They might be wrong, but to overturn that would need a lot of evidence of something else.