CT value and common CT window width and window position [conversion]

I. common CT values

The CT value indicates the number of cycles that occur when the fluorescent signal in each reaction tube reaches the set Domain value. Studies show that the CT value of each template has a linear relationship with the logarithm of the initial copy number of the template. The larger the initial copy number, the smaller the CT value. The standard curve can be made using standard products with known initial copy numbers. Therefore, as long as the CT value of the unknown sample is obtained, the initial copy number of the sample can be calculated from the standard curve. Different gray scales are used to reflect the density of tissue and organ, or absorption coefficients can be used to reflect the density of tissue and organ.

CT value of common human tissue (HU)Tissue CT value tissue CT value
Bone Tissue> 400 liver 50 ~ 70 calcium value 80 ~ 300 spleen 35 ~ 60 blood clots 64 ~ 84 pancreas 30 ~ 55 white matter 25 ~ 34 kidney 25 ~ 50 gray matter 28 ~ 44 muscle 40 ~ 55 cerebrospinal fluid 3 ~ 8 gallbladder 10 ~ 30 blood 13 ~ 32 thyroid 50 ~ 90 plasma 3 ~ 14 fat-20 ~ -100 seepage liquid> 15 Water 0

 

Ii. common CT window position and window width

 

1. During chest CT examination, the window width and window space of the lung window are as follows:

(1) lung window WW1500-2000HU, WL-450--600HU

(2) Diaphragm window WW250-350HU, WL30-50HU

2. bone window, soft tissue window width, window position

(1) bone window WW1000-1500HU, WL250-350HU

(2) soft tissue window WW300-500HU, WL40-60HU

3. Window width and window position settings

The wide window spaces of different windows are used in different parts to fully reflect the anatomical content and focal image performance,

Skull: The window width of brain tissue is set to 80 Hu ~ 100 Hu, the window space is 30 Hu ~ 40 Hu,

The window width of pituitary and Butterfly saddle area lesions should be set at 200 Hu ~ 250 Hu, window 45 Hu ~ 50 HU,

Patients with Cerebral Hemorrhage can change the window width to 80 Hu ~ 140 Hu, window position 30 Hu ~ 50 HU,

Patients with Cerebral Infarction often use a narrow window of 60 Hu, which can improve the detection rate of lesions and clearly show the infarction and softening lesions,

The width of the mirror window is 150 Hu ~ 250 Hu, window position 30 Hu ~ 40 Hu,

The window width is 150 Hu ~ 2 000 Hu, window space 400 Hu ~ 450 Hu,

The window width and window position of the throat and neck, nasopharyngeal, and throat are standing at 300 Hu ~ 350 Hu and 30 Hu ~ 50 HU, able to meet the anatomy and focus display of this part,

Chest: the common chest CT examination is performed by using the left-side window and lung window, and the left-side window can be used to observe the location of the heart and large vascular vessels and the size of lymph nodes in the left-side lobe, enable a maximum of 300 Hu ~ 500 Hu, window position 30 Hu ~ 50 HU,

Lung window width: 1 300 Hu ~ 1 700 Hu, window space-600 Hu ~ -800 HU: On the basis of the above-mentioned basic window width, if you observe the pulmonary fissure and pulmonary vascular, narrow window width and lower window space can be adjusted, and the tumor morphology, segmentation, and pleural sag signs are observed, the observation lung window of burrs increase is clearer than the left-side window,

Abdomen: The window width is usually set to 300 Hu ~ 500 Hu, window position 30 Hu ~ 50 HU,

Liver and spleen CT examination should narrow the window width to better detect lesions, the window width is 100 Hu ~ 200 Hu, the window space is 30 Hu ~ 45 Hu,

Due to a large amount of water in the kidney, the window width is usually 200 Hu ~ 300 Hu, the window space is 25 Hu ~ 35 Hu,

The pancreas is generally 300 Hu ~ 350 Hu, the window space is 35 Hu ~ 50 HU, narrow window 120 Hu ~ 150 Hu and 30 Hu ~ 40 Hu,

Spine and limbs: Regular spine scan shows the soft tissue beside the spine, with a window width of 200 Hu ~ 350 Hu, window space 35 Hu ~ 45 Hu,

The window width is 800 HU ~ 2 000 Hu, window space 250 Hu ~ 500 Hu, the CT value of the bone is about 1 000 Hu, the muscle is about 40 Hu, and the fat is mostly below-50 HU.

 

Organized from online: http://wenku.baidu.com/view/644f7d6d0912a2161479297b.html