MRI terms demystified

SAG – Saggital – From the side. Top of head is up, face/chest are left. backside is right.
AX – Axial – From the top. Face/chest are up. Backside is down. Patient right is right & patient left is left.
COR – Coronal – From the back. Top of head is up. Patient right is right. Patient left is left. First image is front of body.

T1 – Short timing – Pulses (TR or Time of Repetition) are less than 1 second apart. Return signal (Time of Echo) is less than 30ms after pulse. This is weighted for showing proton density (PD), which means fluid and complex molecules.

T2 – Long timing – TR over 2 seconds, and TE over 80ms. This picks up lower density structures better, but rapidly flowing fluid, especially arterial blood, will already be out of frame before the echo is returned. This picks up MS better, because of the high density signal from the plaques and lesions is strongly contrasted by the low signal from the CSF.

FLAIR – Fluid Attenuated Inversion Recovery – Often a T2 image is really a high dynamic range image created from both T1 and T2 echoes. This is used to suppress the CSF signal, while still picking up the details from T1.

Signal differences
Different types of anatomy and pathology return different levels of brightness or darkness. Comparing T1, T2 and FLAIR signal strengths can determine what type of mass exists at a specific voxel (volumetric pixel). This can be compared with reasonable physiology for the area to help provide diagnosis or indication for further assessment.

Reference
An excellent technical detail of magnetic resonance systems is available at:
http://spinwarp.ucsd.edu/neuroweb/Text/br-100.htm
BASIC PRINCIPLES OF MR IMAGING by John R. Hesselink, MD, FACR


General health

I just saw a picture of myself from today’s bike ride, and while I’m still wanting to drop pounds AND fat, I’m about as happy with how I look as I can ever recall being.

In the mirror this morning, I noticed SAGGY BELLY SKIN. This is a good sign, and I’m young enough that skin-shrink is just barely lagging behind fat loss.

Health-wise, my right knee, low back, stamina, and self image all are massively improved. Circulation is better. My BP and cholesterol were good before, so no real change. My resting pulse is down a little bit. I’m having fun exploring and spending time with people. I’m enjoying measuring my progress technically, and seeing myself exceed goals. Also, endorphins.

Also, the rates at which I can convert fat to muscle show me that I don’t have any metabolic issues. “Weight loss is all in my head.” So, picking the right foods will be key. I’ve found I really like Greek style yogurt, and it’s low fat, high calcium, high protein, and only has moderate carbs if I have the mix-up jelly kind (I do).

It seems calorie dense, but it also seems satiating. One day I had 500 calories of it to finish off evening hungers. Then next day I had 2 in the evening. The next morning, I had 2 for breakfast, and had no real hunger for most of the day. I had another before riding my bike, and a snack bar, and some carby elecrolyte drink. I blew through 4000 kcal today and have eaten under 1100 without hunger.

I did have a bunch of caffeine today, so I need to test further. If I could eat 120-240 kcal and be satiated for 6 hours, that’s just famazing and would be a big win for me.

As to wanting to drop pounds and fat:
* I’m 29.6% body fat based on bioelectric impedence, and the increased risk limit is 28%. I’d like to get down to 25%.
* My Waist to Height ratio is 56.7%, and the increased risk limit is 53.6%. I’d like to get down to 50%.
* My Waist to Hip ratio, which is an accurate predictor of morbidity risks, is 95.76%, and the risk limit is 90% for men. I don’t have a target for this other than the risk limit or below.
* I’d like to drop to a size 36 pants due to availability of tall clothes. Also, I found out / confirmed that even men’s clothing is vanity sized by 7-10%, so tape measures differ vs pant sizes.

I just had a life insurance medical exam. It’ll be interesting to see what the CBC comes back with.

Photos, with me on the far right:

or direct: https://scontent-b-atl.xx.fbcdn.net/hphotos-prn1/t1/q71/s720x720/1619156_10203080001591592_2096155125_n.jpg


or direct: https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-ash3/t1/1947922_10202777493151050_1370307925_n.jpg