Ultrasonography

DR C.S.SINGH

DEPARTMENT OF RADIO-DIAGNOSIS

AIMST UNIVERSITY

History

Ability of bats to navigate accurately in the dark –Lazzaro Spallanzani -1794

Other uses-1)under water echo used by submarine to detect war ships-wartime

2) ultrasonic metal flaw detectors

3)ultrasonic therapy-heat effect

4)trawlers to detect fish

What is ultrasound? High frequency sound wave over 20kHz

Non ionising

Soft tissue imaging

Mechanism -Ultrasound Generators Ultrasound is produced by mechanical

movements(oscillations) of a piezoelectric crystal exited by electrical pulses. several crystals are arranged together to form a transducer

Transducer acts as a transmitter and receiver. Image is formed by the reverse of the process used

to create sound waves i.e. returning echoes are converted to electrical signals by the same crystal

Piezoelectric crystal Quartz

Lead zirconate titanate

Different modes of ultrasound A mode: echoes are shown as a peak B mode: brightness Real time: Multiple B mode images seen in

rapid sequence. M mode: Displays motion. Used for cardiac

ultrasound.

A scan A-amplitude Each layer of tissue

produces a different reflection

The A-scan provides data on the length of the eye which is a major determinant in common sight disorders

a = cornea spike b = anterior lens spike c = posterior lens spike d = retinal spike e = orbital spike

B scan B- brightness

Largest amplitude gives rise to brightest spot

                         

Types of probes

ADVANTAGES

No ionising radiation Safe in pregnancy No known side effects Cheap Portable Minimal preparation of patients Non invasive and painless Direct vision for biopsy

Disadvantages Resolution of images is limited

Ultrasound is reflected very strongly when passing from tissue to gas and vice versa

Does not pass well through bone

Disadvantages

• Excessive bowel gas scatters the beam• Obese and kyphotic patients• Operator dependent• Fasting• Full bladder

Major applications Abdomen Pelvis Vascular Small parts Musculoskeletal Neonatal brain

Special applications

Guide needle aspiration

Biopsy of masses

Endoluminal probes provide high resolution images, eg: TVS, TRUS,

TES (for heart and aorta.)

Terminology Anechoic- absence of echoes [clear

cyst, UB]

Hypoechoic- less echoes [darker] than the surrounding tissue.

Hyperechoic- more echoes [brighter] than surrounding tissue.

Ultrasound gel

Applied to the body to eliminate pockets of air between the skin and the transducer

ABDOMINAL USG

Abdominal pain or palpable mass Acute cholecystitis Gallstones Cirrhosis of liver Pancreatitis Retroperitoneum

ABDOMINAL USG

Tapping of ascitic fluid

Localize postop. collections

Drain collections

Hepatobiliary system

Liver Gall bladder

Liver masses

Hemangioma Metastasis

Cholelithiasis

Complicated cholecystitis

Obstructive jaundice

Dilated IHBR Cholangiocarcinoma

Renal system Renal colic Hematuria Palpable mass UTI Anomalies Obstruction

Chronic renal failure

Normal kidney Chronic renal failure

Renal calculi

Hydronephrosis

Dilated calyces UVJ calculus

CHEST

Pleural effusion

Pericardial effusion

Drainage

Biopsy

Pleural effusion

TransudateExudate

PAEDIATRIC Cranial ultrasound

Intussusception

Congenital hypertrophic pyloric stenosis

Midgut malrotation

Developmental dysplasia of the hip

Palpable mass

Cranial ultrasound

Normal Aqueductal stenosis

Subependymal haemorrhage

Coronal section Parasagittal

SMALL PARTS

Testicular torsion Epididymitis Thyroid- differentiate MNG from diffuse

enlargement. Eye: retinal detachment, vitreous

haemorrhage Breast-cystic or solid.

Acute epididymo-orchitis

Testes

Hematocele

Thyroid nodule

Normal

Thyroid inferno

Hyperthyroidism

Breast carcinoma

Venous doppler Venous doppler to

rule out DVT

Incompetent valves in varicose veins

Arterial doppler Peripheral arterial

disease Arterial occlusion Carotid artery

stenosis Renal artey stenosis Aneurysm

Obstetrics

1. Early pregnancy to confirm intrauterine pregnancy and exclude ectopic.

2. Detect viable fetus at 7wks gestation3. Missed abortions, retained products.4. In later pregnancy to assess growth and

exclude anomalies.5. USG guided interventions .-eg. amniocentesis,

chorionic villous biopsy, intrauterine fetal transfusion.

Transvaginal scan

Early gestation

1st trimester- crown rump length

Biparietal diameter [BPD]

2nd trimester

Femur length

3rd trimester

Ovarian pregnancy

Anencephaly Absence of brain and cranial vault.

Failure of neural tube to close at its cephalad end.

Occurs between 2nd-3rd week of development.

Associated anomalies are spinal defects and polyhydramnios.

Anencephaly

Double bubble sign

Dilated stomach and duodenal cap

DOUBLE BUBBLE SIGN Suggests fetal duodenal obstruction.

Causes: Duodenal atresia, duodenal stenosis, annular pancreas, Ladd’s bands, volvulus.

UMBILICAL CORD 3 vessel cord.(2 arteries,1 vein)

Single umbilical artery is seen in 0-2%-1.1% of deliveries.

Associated abnormalities; cardiac defects, hydrocephalus, omphalocele, diaphragmatic hernias.

3 cord vessel

2 arteries and 1 vein

2 vessel cord

Types of placenta previa

Complete placenta previa

INCOMPETENT CERVICAL OS

Painless 2nd trimester abortions.

Cervix length <3cm, gaping internal os, funneling of membranes into endocervical canal.

Incompetent os

Musculoskeletal Congenital dysplasia of the hip Joint effusions Hemangioma Nerve sheath tumours Soft tissue sarcomas Superficial metastasis

Indications

Popliteal cyst Ganglion cyst Abscess Tendon rupture

Hip joint

Effusion

Tendon Rupture Abscess

Popleteal cyst Ganglion

ECHO – TTE and TEE Assess velocity of blood flow Assess cardiac valve and

function Motion of the ventricular wall Hypertrophic cardiomyopathy

(TTE-trans thoracic

TEE-Trans esophageal)VSD