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胸部電腦斷層掃描 CT of chest.

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Presentation on theme: "胸部電腦斷層掃描 CT of chest."— Presentation transcript:

1 胸部電腦斷層掃描 CT of chest

2 History of X-RAY

3 螺旋電腦斷層掃描之優點 可以在一次閉氣的時間內掃描完所要切的範圍 對於無法配合閉氣的病患降低移動假影的產生
可以提供不同角度重組所需之切面影像 可以取得3D之影像協助診斷

4 胸部電腦斷層 胸部電腦斷層掃攝影幫助判斷胸部X光片 上所見到的不正常影像,代表良性腫瘤或惡 性腫瘤外,往往還可以查覺到X光片上無法顯 現的病灶,尤其是縱膈腔淋巴結的評估,是 肺癌分期時的重要檢查。

5 解剖Anatomy

6 Lung

7 vessel

8 Bronchus

9 Mediastinum

10 胸部電腦斷層之適應症 評估胸部X光片上所見到的不正常病灶 診斷X光片上無法顯現的病灶,尤其是縱膈 腔腫瘤的評估 肺癌分期 肺部轉移病灶
胸腔外傷評估 咳血(hemoptysis) 肺栓塞(Pulmonary embolism) 主動脈疾病(aortic dissection, aneurysm)

11 病患檢查前之準備 如需施打顯影劑,檢查前必須禁食四小時 確定病患腎功能指數是否正常 含碘顯影劑禁忌症:
有顯影劑過敏病史、氣喘病、過敏體質、 嚴重之肝、腎、心血管疾病、多發性骨髓瘤、 凝血機能障礙及甲狀腺機能異常等。

12 Injection of Contrast medium
The use of contrast media which injected intravenously is important for visualization of structures within the mediastinum. Department protocols/radiologist preferences determine the specific type, volume and site of injection. ( Average dose 80 ml) For children 1.5 ml per kilogram body weight.

13 The advantage of contrast media
1. To detect lesions 2. To distinguish vessels from lesions 3. To demonstrate displacement of vessels by masses 4. To demonstrate the enhancement of pathologies

14 Technical parameter 切面厚度Slice thickness 切面間距Slice spacing
視野Field of view 重組函數Reconstruction algorithm 影像呈現設定Imaging display settings

15 Slice thickness Single attenuation value of voxel represents average of all attenuation of all various structures within it Thicker the slice greater the averaging called partial volume effect Partial volume effect reduced by thinner section Determined by size of structure being assessed and number of scans required to evaluate the patient

16 Reconstruction algorithm
Reconstruction algorithm Lung parenchyma :high spatial algorithm High spatial algorithm reduces smoothing Better depiction of normal and abnormal parenchymal interface Mediastinum and chest wall standard soft tissue algorithm


18 Slice spacing Slice spacing Adequate assessment of patient 10 mm interval 1 to 2 mm slice with 10 mm interval allows only 10 to 20% of lung Improved spatial resolution allows better assessment of normal and abnormal findings Pulmonary metastasis requires 5 to 7mm thick sections Trachea and central bronchi 3 to 5mm thick sections Pulmonary parenchyma and peripheral bronchi requires 1 to 2 mm sections

19 Image display settings
Image display settings Two parameters: window width and window level Average density of each voxel : Hounsfield unit These units are arbitrary so 0 is for water, for air Range of Hounsfield in thorax is wider ranging from -850HU for aerated lung to 700HU for ribs Display of images determined by window level and window width

20 Optimal window levels

21 高解析胸部電腦斷層High resolution CT of chest
對於瀰散性肺部疾病,利用高解析電腦斷層 (HRCT)用1或1.5mm 厚度掃描,評估肺間 質或氣管。 對於後側動脈依賴部份的肺野病變可加做 prone 的 HRCT。 對於小呼吸道疾病可加做吐氣之HRCT。

22 Indications of HRCT Solitary pulmonary nodule
Evaluation of diffusely CXR -Cystic fibrosis, Sarcoidosis, Interstitial lung disease, Histocytosis X, ARDS

23 HRCT ‐ Technical summary
A narrow slice width is used (usually 1–2 mm) A high spatial resolution image reconstruction algorithm is used Field of view is minimized, so as to minimize the size of each pixel Prone scanning

24 Thin thickness same Reconstruction in High resolution algorithm
5 mm 1 mm same Reconstruction in High resolution algorithm same scan data

25 Reconstruction algorithm
high resolution (sharp) standard resolution (smooth) SL 1 mm same position

26 Field of view A Scan FOV 40cm B Target FOV 25 cm

27 Protocol of Chest CT

28 Routine CHEST ( Lungs and Mediastinum)
Indications :General screening of Pathology Patient Position :Supine arms elevated above head Topogram: from chin to below liver Breathing Breath hold in inspiration ( single breath hold) Contrast I.V : 80 ml

29 Scan range C-: 5mm/5mm (Soft tissue widow ) from lung apices to liver
from chin to kidney

30 Recon. Lung window 5mm/5mm (lung apices to below diaphragm)
Cor. 5mm/5mm

31 High resolution CT Patient Position :Supine arms elevated above head
Topogram :From lung apices to liver Breathing :Breath hold in inspiration ( single breath hold) Contrast I.V : 80 ml

32 Scan range C-: Inspiration: 1mm/5mm (lung window )
from lung apices to diaphragm Expiration: 1mm/5mm (lung window) 5mm/5mm (soft window) From lung apices to liver

33 Recon. C+: 5mm/5mm (Soft tissue widow) from chin to kidney
Cor. 5mm/5mm Lung window 5mm/5mm

34 CT angiography Patient Position :Supine arms elevated above head
Topogram :From chin to aortic bifurcation Breathing :Breath hold in inspiration ( single breath hold) Contrast I.V : 80 ml (2.5mm/s)

35 Scan range C-: 5mm/5mm (Soft tissue widow ) from lung apices to IC
Bolus tracking ROI setting at aortic arch C+: 5mm/5mm(Soft tissue widow ) from chin to IC

36 Recon. Lung window 5mm/5mm Sag.3mm/3mm Cor..3mm/3mm


38 Anatomy of chest CT

















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