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Clinical aspects of US, X-ray and CT

Viktor Bérczi, MD, PhD, DMScprofessor and chairman

Semmelweis University, Budapest, Department of Radiology

Ultrasound

What we need for the Ultrasound examination?

• „Examination tool” – US equipment with transducers

• Proper knowledge – from different anatomical, biophysical, anatomical, biophysical, pathophysiological, radiological, clinical aspects….

Advantages of the US examinations

• We don’t use ionizing radiation• Good accessibility• Relatively short waiting list, short booking time• Relatively low cost (compared to the CT and MR)Relatively low cost (compared to the CT and MR)• With portable US machines, examination at bedside,

at the emergency dept, in the ICU, or in the operating theater is also possible

Disadvantages of US

• Not useable in the gas or bone covered territories (mainly in the chest, skull)

• Poor visualisation in obese patients

• Operator dependent• Operator dependent• Moderately useful in some postoperative

conditions (not good skin contact, difficulties with catheters, bandages)

Physical theory of US?

• Vibration of piezoelectric cristals. Very small ceramic parcels which after electonic vibration produce mechanical vibration -------ULTRASOUND ULTRASOUND

• These piezoelectric cristals work as transmitter and reciever of US, alternatively.

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The US image

• Reflections from different parenchymal organs and surfaces, than the computer collects these transmitted reflections and converts low voltage

informations for a so-called shadow-imageinformations for a so-called shadow-image(this is a real-time image 14-25 frame/sec - compiled with proper, fast computers).

• The reflection of the different tissues are featured with ECHOGENICITY

• The strength of the reflections: ECHODENSITY

Ultrasound terminology- types of US echogenicity

• Anechoic - cystic (good ultrasound transmission)

• Hypoechoic • Hypoechoic • Hyperechoic• Hyperdens (completely reflects the

Ultrasound)

Territories of Ultrasound examinations

• Gynecology – Obstetrics• Cardiology• Emergency Dept• Internal Medicine Dept• Traumatology• Surgery• Surgery• Orthopedics, Rheumatology• Urology• Angiology, Surgery• Dermatology• ORL• Ophtalmology

Different US modes• A – mode (measurement of reflected US

-- distance measurement –Ophtalmology)

M – mode (motion) B – mode (brightness)

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Doppler US Color Doppler US

Power Doppler US Ultrasound

Ultrasound probes

• Convex

• 3,5-5,5 MHz• Deep penetration

• Linear

• 8-10 (or more) MHz• Superficial penetration• Deep penetration

• Poorer resolution

• Superficial penetration

• Better resolution

Konvex vs. linear probeileum

ileum transv.

ileum long.

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If use it, use it well

less gain than needed more gain than needed

proper gain

Vascular examination

a. fem. v. fem.

v. fem. prof.

Vascular examination Ultrasound guided interventions

Fine-needle aspiration biopsy (FNAB) of the right parotid

Endocavital US

transrectal transvaginal

More options

uterus

urinary bladder

Approximately 8 weeks-old pregnancy

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And more…

cardiology

urology

pediatric

Neurology – transcranial doppler (TCD)

X-ray

-- +A-C

3: Evacuated glass envelope

1: Cathode filament

2: Anode – Tungsten target

- +A-C

Window

X-rays

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Indication of chest x-ray

• High fever

• Respiratory symptoms• Physical disorder• Physical disorder• Primary tumor

• Traumatic injury• Abdominal emergency• Pre-, postoperative condition• Chest screening

Method & strategy (chest)

• Zeiss/ Odelca

• 1:1 P-A CXR• Sagittal view• Sagittal view• Fluoroscopy

• CT (CAT)• Perfusion & ventill. lung scintigraphy• Angiography, bronchography

www.medwww.med--ed.virginia.edued.virginia.edu

Pneumonia Tuberculosis

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PTX Metastasis

abdominal emergency• Perforation• Ileus• Crampy pain (gall-stone, renal stone) • Inflammation

appendicitis

Indication of abd xIndication of abd x--ray:ray:

– appendicitis– pancreatitis– diverticulitis– extrauterin gravidity– adnexitis

• mesenterial thrombo-embolism

PERITONITIS - PARALYTIC ILEUS

Method & strategy (abd)

• Chest X-ray!! (free abdominal gas?)• Plain abdominal radiograph & fluoro• Swallow examination• Follow-through examination• Follow-through examination

• Barium enema study (urgent - monocontrast)

• US• CT (CAT)

Free abdominal gas

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Small amount of gas Small amount of gas

2 ml2 ml

Plain abdominal film

Feeding tube positioningFeeding tube positioning Ileus(small-, large bowel) mechanical obstruction

• Stenosis – stricture – obstruction– Congenital : atresia, stenosis, anal imperforation– Aquired

• Inflammation• Inflammation• Tumors• Obstruction• Adhaesion• Strangulation • Hernia• Volvulus• Intussusception

Ileuscaused by inflammatory process

• Regional enteritis (Crohn’s disease)

• Ulcerative colitis• Diverticulitis• Tuberculosis• Tuberculosis

• Actinomycosis

Ileuscaused by obstruction

• Gall-stone

• Foreign body• Helminthiasis• Stercolith • Stercolith

• Tumor

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Ileussmall bowel, mechanical obstructive

Complete small bowel ileus

Large bowel ileus Paralytic ileus

Drug intoxication!Drug intoxication!

Appendicitis

UH

Acute pancreatitis

CT

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Esophageal cancer Epiphrenal diverticulum

Barium enema study

Double contrast

Polyp

Zs, Tarjan PhD

Zs, Tarjan PhD

Colorectal cancer

Apple core sign

Bone tumor

Bidirectional!

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CT-pyelography iv. pyelographia Fracture

Met. cranii

Computed tomography - CT

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Historical steps

• Röntgen, Hounsfield és Cormack• 1967: first CT image (9 days• 1972: prototype• 1974: first clinical CT (skull)• 1974: first clinical CT (skull)• 1976: whole body CT (one slice 20s)• 1979: Nobel prize• 1990: spiral CT• 1992: multislice CT• 2006: 64 slices (more and more slices . . .)

scan of chest or abdomen few seconds only• today: PET-CT, dual-source/dual energy CT

http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct

http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct

http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct

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http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct

http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct

http://www.impactscan.org/slides/impactcourse/basic_principles_of_ct

Digital image

• Pixel: 2D, usually 0.5x0.5 mm

• Voxel: 3D „bricks”, usually 0.5x0.5x0.6-5.0 mm

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Tissue densities

• -1000 HU vacuum

• -100 HU lipid• 0 HU water• 0 HU water• 20 HU dens liquid

• 20 – 80 HU soft tissues• 70 – 100 HU fresh bleeding • 100 – 1000 HU contrast medium,

calcium

Brain window

upperframe:80 HU

lowerframe:0 HU

window width: 80 HU

windowcenter:40 HU

Hounsfield scale (HU)

• Brain window

• WW = 80 HU• WC = 40 HU

Windowing techniques

soft tissue window lung window

Brain window bone window

Spiral (helical) CT Multidetector spiral CT

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Dynamic CT scan

• Iodinated contrast medium i.v. injection

• One or more scans from the same region following contrast medium injection

• The time-course of contrast-enhancement is • The time-course of contrast-enhancement is detected

HRCT (high resolution CT)

• Slim slices

• High resolution images• Larger x-ray dose• Longer scan time• Longer scan time

https://en.wikipedia.org/wiki/High-resolution_computed_tomography#/media/File:Pulmon_fibrosis.PNG

Dual Source/dual energy CT

• Two x-ray tubes and two detectors are used simultaneously

• The two tubes are perpendicular to each other• Dual source: same kV in both tubes• Dual energy: x-ray voltage is 80 kV and 140 kV, • Dual energy: x-ray voltage is 80 kV and 140 kV,

rotation of the two tubes are 180o

• Attenuation of the two x-rays will be different, making fine tissue specification possible

http://www.healthcare.siemens.com

Advantages of dual source CT scan

• Better resolution• Lower x-ray dose• Better tissue differentiation• Direct vessel or bone subtraction• Staging of oncology patients• Staging of oncology patients• Characterisation of vascular plaques

• Differentiation of fluids in emergency medicine

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Anterior communicans artery aneurysma - CTA

Pneumothorax and subcutaneous emphysema

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Virtual colonoscopy CT-guided biopsy

Radiofrequency ablation (RFA) of osteoid osteoma Radiofrequency ablation (RFA) of osteoid osteoma

Radiofrequency ablation (RFA) of osteoid osteomaAortic arch aneurysm rupture

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Aorta B-type dissection Intramural haematoma – native CT

Intramural haematoma – contrast enhanced CT Multiple renal arteries

Renal artery Renal artery aneurysmaneurysm

Volume rendering

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Bilateral renal stents: CTA „curved” reformationBilateral renal stents: CTA „curved” reformationVolume rendering

Lower limb CTALower limb CTAAcknowledgements

• Attila Kollár, consultant radiologist

• Ildikó Kalina, consultant radiologist• Katalin Kiss, consultant radiologist• Peter Magyar, assistant professor• Peter Magyar, assistant professor

• Dóra Kozics, radiology resident

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