Pi R Squared

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For my inaugural hair blog podcast or whatever you like to call it. I’m going to talk about PI R squared. Before all of you freak out who are not math aficionados. Don’t worry. I am not a big fan of math myself. My wife who is a physics and math major is a genius in math and probably could tell you a lot more about PI R squared a than I could. Now, why am I talking about this weird geometry? Well, I actually use this formula every day as I talk to my patients and I’ll explain to you why. So PI R squared is the geometric description of area for a circle and is applicable to a hair transplant. The reason it’s important is several fold. First is the caliber of a hair. So if you think about various factors that can lead to improved visual density from a transplant because a lot of people say, well, how many grafts do you use? 

Do you use 2000 grafts, 3000 grafts? Well, are those grafts mean that they consist of only one hair or two hairs? There are a lot of variables. And, and so things that can contribute to a better outcome would include the caliber of hair, the thickness of the hair shaft, the contrast ratio. So let’s say that the hair shaft is white against white skin that would look visually, visibly denser than say black hair on white skin or vice versa, whites hair on black skin. So color-contrast ratios, favorable curl. If the hair is very, very curly, then the, it is much harder to see the scalp because it really definition of bald. This is not just the absence of hair, but the visibility of how a bald scalp looks through thinning hair. So all of those factors can be a contributory element toward getting a better denser results. 

So let’s sayI transplant a thousand grafts in someone with dark jet black hair, straight hair on very pale white skin that’s very thin caliber. That is probably the worst result. I mean in terms of comparing the differences between the thicker between one person getting a thousand grafts and another person getting a thousand grafts. There are so many variable factors, but the caliber is so important because if you use that PI R squared. R is the radius. Pie as you know, is 3.1415. It’s just a numeric number fixed to a constant. But if you look at the radius squared if I double the radius, the surface area is quadrupled. So if you quadruple the surface area, it’s four times denser. So let’s compare two hair shafts, one hair shaft as a particular radius. 

Let’s say it’s a certain distance of let’s say it’s arbitrary to 2 R and another person has a measurement of four micro millimeters or whatnot. If you look at the surface area that hair is covering, let’s say it’s that 2, it’s two squared is four. So it’s four units of density to let’s take that person that has double the radius. That’s as I said, it’s an arbitrary four will four squared is 16, 16 versus four that is four times the density. So you can see that just doubling the radius can give you a density four times greater. So caliber of the hair is something that people don’t always talk about. They always talk about number of grafts, et cetera. But for me, when I look at a donor, a density, I’m looking at the caliber of the hair is one of the most important areas in the way that I communicate is this formula PI R squared. 

Hopefully that makes sense. On the flip side of that, another time I talk about Pi squared is the crown. So the crown is, if you listen to some of the lectures I’ve given on the crown is an area that’s particularly difficult to achieve full visual density. Because on the vertical scalp, it’s a, sometimes a big area that gets bigger. And as you, as that hair starts to miniaturize, it gets wider and wider. So it’s a big area to cover. So you have to do a lot of cheating methods to get better visual density. And that’s discussed in a lot of my other videos. And I’m sure I’m going to do a blog or just on crown cause I’m very passionate about crown, uh, baldness. But for the sake of this blog, that specifically or podcast specifically talking about PI R squared, how is relevant the PI R squared, the radius. 

Now let’s say I doubled the radius of the crown as remember that radius squared is the surface area. Now that surface area becomes four times greater. I have to use four times the number of grafts if I just simply double the radius and people don’t think about that. So dealing with the crown, you have to be creative in how you execute on the crown from angles, density gradients and all those things. Not only to achieve a natural result, but also to reduce the odds of having a visual result. But also to create a beautiful dense result is far as you can progress placed. So this is why I always tell my patients that when I look at a crown, when that crown gets relatively larger, it is either something that I cannot achieve or accomplish or I’ve got to cheat more or tell them, give them a realistic expectation in terms of the full density, especially after a single session. So those are the two ways that I use PI R squared, a simple geometric formula, but we learned in high school and apply it every day in terms of communicating with patients about achievable results with hair transplantation. So hopefully that gives you some ideas about that. Come to see me in Plano, Texas, just North of Dallas, Texas. I’ve been in practice about 20 years doing hair restoration, doing everything from FUE, FUT, female hair transplant, designing eyebrows, ethnic, corrective, practically everything.


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