Emergency Ultrasound (EUS)教學(9)

急診超音波在骨骼軟組織之應用

新光醫院急診醫學科

陳國智醫師

中華民國醫用超音波學會指導醫師

30M, abdominal pain for one week

Outlines

• US anatomic considerations

• Skin and soft tissue infection

• Foreign body localization

• Abdominal wall mass evaluation

• Bony fracture evaluation

• Imaging of tendons, joints, and muscles

正常組織超音波影像 • Skin

– Echogenic

• Subcutaneous tissue – Hypoechoic

– Traverse by irregular strands of hyperechoic connective tissue

• Fascial planes – Hyperechoic; regular thickness

• Muscles – Striated appearance on long axis scan

• Tendon – Fibrillar; echogenic

• Vascular structures – Anechoic (Artery versus Vein)

• Lymph nodes – Irregular, circular, echogenic; with hypoechoic rim

• Bones – Echogenic cortices and dense acoustic shadows

掃描注意事項

• 高解析線形探頭 (5-10MHz)為第一首選

• 注意深度(depth)和焦點(focus)的設定

• 適當應用探頭施壓

• 至少掃描兩個介面 (longitudinal & transverse)

• 考慮和對側比較 & 呈現在同一畫面 (Split screen)

• 如何改善掃描品質 – Stand-off pad

– Water/gel-filled glove

– Water bath technique

Water/gel-filled glove

皮膚 & 軟組織感染

EUS在皮膚 & 軟組織感染的應用

• 須熟悉正常超音波軟組織影像

• 認識週遭組織及結構

• 協助設定最佳切除及引流路徑

• 正確診斷不明顯膿瘍

診斷

• 正確定位不明顯膿瘍

定位

• 協助膿瘍引流

處置

皮膚 & 軟組織感染

• Cellulitis – Cobblestone-like appearance

• Subcutaneous abscess – Variable appearance

– Most: hypoechoic; spherical mass

– Content: • Hyperechoic sediment

• Septae

• Gas

• Isoechoic or hyperechoic

• Liquefied pus – induced motion of the

content

• Necrotizing fasciitis – Marked thickened of SC layer

– A layer of anechoic fluid, • greater than 4 mm

• adjacent to deep fascia

– Subcuatneous gas • Acoustic shadow

• Reverberation artifact

Cellulitis

• Nonspecific

• Indicative of edema

• Skin

• Subcutaneous tissue

• Compare to unaffected side

Normal v.s. Cellulitis

Soft-tissue US changes cellulitis

management (56%, 71/126)

Tayal VS, et al. AEM. 2006;13:384-388

EUS improves accuracy of superficial

abscess detection

Squire BT, et al. AEM. 2005;12:601-606

Chest wall cellulitis & abscess

70F, PN with chest wall abscess

Dorsal foot cellulitis with clinically

unsuspected coexistent abscess

Soft tissue with abscess

Thigh abscess

(Lesion side v.s. Normal side)

Soft tissue abscess

Thigh abscess

Subcutaneous abscess (Thigh)

Buttock abscess

Thigh cellulitis and abscess

Antecubital fossa abscess

Post-op abdominal wall abscess

Gas-forming abscess

L’t groin pulsatile mass

NTUH experience

• diffuse thickening of the SC tissue

• a layer of fluid accumulation more than 4 mm in depth along the deep fascial layer

• 66 patients (17,NF)

• Sensitivity: 88.2%

• Specificity: 93.3%

• PPV: 83.3%

• NPV: 95.4%

• Accuarcy: 91.9

Yen ZS, et al. AEM. 2002;9:1448-1451

72M, NF of left forearm

Chronic Lymphedema

Skin & Soft Tissue Infections

Clinical decision making

Cellulitis

No suspicion of abscess

Skin and soft tissue infection

Obvious abscess

Fluctuant or draining

Possible or suspected abscess

No fluctuance

I & D EUS Abx

Consider NSTI

Abscess seen No abscess seen Localize

collection

Pitfalls

• Abscess are not always hypoechoic

• Failure to consider necrotizing soft tissue

infections

• Failure to recognize adjacent structures

軟組織異物

軟組織異物診斷及定位

• 殘留軟組織異物

–易使受傷的皮膚及軟組織產生併發症

–常不易由病史和理學檢查查覺

– 38% 在第一次就診時無法診斷出來

–為常見的醫療糾紛原因之一

軟組織異物診斷及定位

臨床應用

• 協助診斷X-ray不易查覺異物 (radiolucent)

• 定位異物及辦識其特性及週遭結構

• 協助異物移除

軟組織異物

• 常見異物 – glass, wood, metal, plastic, gravel

• 異物: – Size; material; retained period

– Hyperechoic

– Variable acoustic shadow

– Variable reverberation artifact

• 殘留異物超過24-48小時 – 因組織反應，會在異物周圍形成一圈 (hypoechoic halo)

軟組織異物

移除技巧

• Ultrasound-guided incision

• Real-time ultrasound to guide placement

of forceps or a hemostat next to the FBs

(linear FB)

• Ultrasound-guided needle localization

Normal thenar eminence

Chicken thigh with stand-off pad

Wooden toothpick

Wooden FB

Needle

Broken needle fragment

Chest wall bullet

BB

Linear glass shard

Broken glass bottle

Plastic toothpick

Gravel

Left thigh FB

Case

Swollen digit

Finger X-ray

Wood fragment

Time matters

30M carpenter

Wood splinter

Needle approaches FB

Pitfalls

• Inadequate knowledge of the regional

sonographic anatomy

• Failure to take necessary steps to optimize

scanning of small superficial objects

• Other pitfall

• Foreign body removal

骨折評估

骨折評估

• 肋骨骨折

• 胸骨骨折

• 長骨骨折

• 堅困環境骨折

• 骨折復位

• 脫位復位

• FASTER

骨折評估

• 骨表面產生不連續線條

• 骨折周圍低回音血腫

• 掃描時注意最痛點

• 至少進行兩個介面掃描

Rib

Normal rib

Rib fracture

Rib fracture

Rib fracture

Normal sternum

Sternal body fracture

Femur

Femoral shaft fracture

Tibial shaft fracture

Pitfalls

• General pitfalls

• Rib pitfalls – Pseudofracture

– Misidentify pleura for a rib

• Sternum fracture pitfalls – Sternomanubrial junction

– Hypoechoic pectoralis muscle

• Long bone fracture pitfalls – Exellent for only midshaft fractures

關節液評估

Elbow effusion

(Olecranon fossa)

Hip X-ray

Axis for imaging hip effusion

Normal v.s. Hip effusion

Septic arthritis of right hip

Suprapatellar effusion

US guided arthrocentesis

Ankle sonogram

肩關節復位評估

Verify shoulder reduction

AJEM 2009

40F, Should dislocation

& post-reduction

Take Home Message

• 急診超音波可協助骨骼軟組織之臨床診斷，及協助進行相關處置

• 第一首選為高頻線形探頭

• EUS對臨床診斷及決策有立即幫助的應用才是最需要學習的項目

JUICE BAR

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