I think every man over 30 should be monitoring his arterial plaque and, if you care about your erectile strength, I am sure you agree with me. Of course, you can do that with a Heart Scan (or Calcium Score) as I did, but that involves some radiation, which makes many men uncomfortable. As Dr. Davis points out in Track Your Plaque, a Heart Scan directly measures the plaque in the cardiac arteries and that plaque is the one most likely to kill you if it ruptures. So for some men, a Heart Scan may be the most appropriate. But I believe all men should monitor their plaque and this is where an IMT can come into play.
What is an IMT? It is a carotid (neck artery) ultrasound that has been used in many studies to monitor atherosclerosis (arterial plaque) and has a rich and broad research history behind it. According to Track Your Plaque, it has about a 60-80% correlation with cardiac plaque so, while it's not perfect, it does have some solid association. The beauty of an IMT is that, as of this writing (in most states), you can order one through Lifeline without a doctor's orders and it is only $70. (I have no affiliation.)
Why would anyone go to all this trouble to measure their atherosclerosis? Isn't arterial plaque just a part of life? No, it does not have to be. Several men, that I call the Plaque Regressers have founds consistent ways to reverse atherosclerosis and part of this, obviously, requires the ability to monitor your progress. I have a significant amount of coverage on my site on the topic and you can start with my Links for Improving Erectile Strength for more information.
Consider these other Ultracritical Reasons to Monitor Your Arterial Plaque:
a) Erectile Dysfunction. The fact is that it doesn't take a lot of plaque in your penile arteries before erections start taking a little longer and things start becoming a little softer. And even if you are young, that does not mean you are completely immune. In my page on Young Men and Erectile Dysfunction, I discuss how many studies have shown that about half up to even two thirds of men in their 20's and 30's already have significant arterial plaque.<
If you have plaque, you probably want to focus on reversing it and clearing out those penile arteries. This will improve blood flow and improve nitric oxide levels, all of which will help you in the bedroom. See my page on How to Clear Your Arteries for more information. One of the things that I see on the Peak Testosterone Forum is men with erectile dysfunction who simply refuse to believe that their issues could be caused primarily by atherosclerosis. But the fact is that aterial plaque is the root cause of most erectile dysfunction in modern cultures.
b) Heart Attack Risk. As the plaque mounts and/or if it grows quickly, you are at an ever-increased risk of a heart attack or stroke. In the U.S. alone, there are about 735,000 heart attacks per year, resulting in 370,000 deaths. And another 240,000 will die each year of other heart-related issues.
Okay, so let's say that you are on board and decided to actually measure your arterial plaque via an IMT. How do you know if your readings are normal? Or, better yet, how do you know if they are ideal? It turns out that there has been quite a bit of research on the subject and they are even published full studies in the public domain, clearly for the purpose to help us with attacking heart disease. Here is a sampling of that material:
NOTE: A Heart Scan is actually the initial route I chose and you can read about it here: My Heart Scan Results. (Next time I will get an IMT as my Heart Scan showed zero cardiac plaque and I don't want any more radiation unless absolutely necessary.)
CAUTION: Always go by the results and analysis provided by your specific lab and/or physician. Techniques and methodologies can vary testing results.
1. Non-Cardiac Patients. Spanish researchers studied hundreds of relatively healthy patients with the following criterion: "The inclusion criteria were no personal history of cardiovascular disease, no premature cardiovascular disease in first-degree relatives, cigarette consumption less than 15 pack- years (number of cigarettes smoked per day in packs, multiplied by the number of years of smoking), no diagnosis of dyslipidemia, arterial hypertension, or diabetes mellitus, and no serious illness requiring admission to hospital in the past year." 
Here are the results from this study by age bracket for men only and the purpose is to give us a picture of relatively health aging of the arteries:
2. Patients Without "Obvious" Atherosclerosis. This study eliminated all patients with obvious narrowing the arteries. Doing so yielded a nice picture of a more "healthy" age progression: 
Their concept was to give us a pattern for healthy arterial aging. As you can see, in this case even late seniors were able to keep their IMT below 1.00 mm. Keep in mind that the above values are women and men grouped together and, as I mentioned, men tend to be a bit higher. Notice, though, how similar the results are to #1.
3. Rome, Italy General Population Study. One clinic just kept track of 1,600+ patients in a row. Interestingly enough, the results were quite similar to #1. Unfortunately, the did not break it out by gender and women tend to have lower IMT's than men. However, the general pattern and slope of the Spanish was definitely confirmed. 
As you can see from the above, there is a "natural" progression of aging in IMT scores even in those living a relatively heart-healthy lifestyle. Of course, many of the supercultures likely have little to no atherosclerosis and so their scores are probably even a bit lower. One such people are the Tarahumara Indians of Mexico and I give coverage to them here if you are interested: The Tarahumara Diet.
However, the point is that researchers have looked at all this data and the above studies and come to some conclusions: By looking at the above stats, you can see for yourself how they came to these conclusions:
1. 1.0 mm Is Somewhat Risky for Old and Young; 1.2 mm is High Risk. The authors were clear that "it is common practice to call a CCA IMT >1.0mm as being abnormal, and >1.2mm as being high risk. There is general agreement that the presence of obvious plaque indicates high risk at any age. However, when there is only CCA IMT thickening and no plaque then the normal values need to be adjusted for age, gender and perhaps even ethnicity. 
Very similar thinking was echoed by researchers when they stated that "we defined plaques nonarbitrarily as a localized area of thickening of >1.2 mm because we believe that plaque should be considered to be qualitatively different from general increases in wall thickness. Plaques were very common in both men and women, and, in contrast to IMT, the presence of plaques was strongly associated both with cardiovascular risk factors and with prevalent cardiovascular symptoms and diagnosed disease. ."
Notice that both sets of scientists noted that arterial wall thickness increases with age and so your IMT score must take this into account. Thus, if you exceed the average progression by age, then you likely have plaque and are at risk. However, if you are over 1.2, you definitely have significant plaque according to their research and, clearly, anything over 1.0 likely is indicative of problems as well, because even senior-aged healthy individuals have IMT's less than that number.
2. An Increase Over .02-.05 mm Per Year. According to some guidelines, you should also watch the rate of change in IMT. Notice that 1.0 and 1.2 figures from #1 are supported as well:
"It was suggested that an average thickness of the combined intima and media ranging between 0.5 and 1.2 mm is considered to be normal, and that >1.2 mm is used to define the presence of a plaque. It was also reported that the abnormal range of IMT is age dependent, and an IMT >1.00 mm is considered highly abnormal in younger patients, and is sometimes used as the cutoff in clinical trials (Feinstein 2002). The estimated progression of atherosclerosis per year is 0.02 to 0.05 mm (Feinstein 2002). IMT may be a potential useful marker for coronary atherosclerosis, as well as an indicator for its progression or regression, on the condition that the carotid atherosclerosis reflects coronary atherosclerosis." 
SUMMARY: Ideally, one would work with a qualified cardiologist or other physician that has a passion for plaque reversal.
1) Rev Esp Cardiol, 2010;63:97-102, "Carotid Intima-Media Thickness in Subjects With no Cardiovascular Risk Factors"
2) Stroke. 1999; 30: 841-850, "Carotid Plaque, Intima Media Thickness, Cardiovascular Risk Factors, and Prevalent Cardiovascular Disease in Men and Women"
3) J Ultrasound Med, 2007, 26:427â€“432, "Common Carotid Artery Intima-Media Thickness Determinants in a Population Study"
4) http://www.pulsus.com/ccc2010/abs/090.htm, "NORMAL VALUES FOR COMMON CAROTID INTIMAL MEDIAL THICKNESS SHOULD BE ADJUSTED FOR AGE", MF Matangi, DW Armstrong, M Nault, D Brouillard
5) Group Health Cooperative, Clinical Review Criteria, "Carotid Intima Media Thickness (IMT or CIMT) for Coronary Artery Disease Screening and Monitoring"