INTRODUCTION to INTRODUCTION to RADIOLOGYRADIOLOGY

Carol P. Becker, M.D.Carol P. Becker, M.D.

Stephanie Casey, M.D.,M.P.H.Stephanie Casey, M.D.,M.P.H.

MAIN ADVANTAGES MAIN ADVANTAGES OF OF

CTCT OVER MRI OVER MRI

Rapid scan acquisitionRapid scan acquisition

Visualization of Visualization of cortical cortical bonebone and soft tissue and soft tissue calcificationscalcifications

Multi-Detector (Helical) CTMulti-Detector (Helical) CTmultiple planes of detectors in the multiple planes of detectors in the

gantrygantry

Technical innovation allowsTechnical innovation allows

– even even fasterfaster scanning scanning

– over a much longer rangeover a much longer range

– with even better image qualitywith even better image quality

Radiation exposure greater than single-Radiation exposure greater than single-detector CTdetector CT

“ “Total body” CT in trauma ptsTotal body” CT in trauma pts

1616TB Cavity w FBCT SCAN

NormalNormal

Trachea

Aorta

Interlobarartery

Rt interlobarartery

Confluent shadow of right interlobarartery and superior vein

Lt interlobarartery

Spine Note:Density is darkerinferiorlyRt diaphragm

Chest RadiologyChest Radiology

Pneumothorax: “Pneumothorax: “deep sulcus” signdeep sulcus” sign

Pneumonia or Pulmonary Edema Pneumonia or Pulmonary Edema Airspace Disease:Airspace Disease:

Silhouette Sign & Spine SignSilhouette Sign & Spine Sign

PneumoperitoneumPneumoperitoneum: perforated : perforated viscusviscus

Right pneumothoraxRight pneumothorax

Lingular PneumoniaLingular Pneumonia

NL?

PNEUMO

PERITONEUM

PLAIN RADIOGRAPH

Hounsfield Unit Scale Hounsfield Unit Scale (CT Attenuation)(CT Attenuation)

Gas (Air)Gas (Air) -1,000 HU-1,000 HU

FatFat -100 HU-100 HU

WaterWater 0 HU0 HU

Soft tissueSoft tissue +20 to +100 HU+20 to +100 HU

BoneBone +1,000 HU+1,000 HU

Radiographic DensitiesRadiographic Densities

Metal Very WhiteMetal Very White

BoneBone White White

Water GrayWater Gray

Fat Gray-BlackFat Gray-Black

Air BlackAir Black

Metal is most Metal is most RadiodenseRadiodense oror Radiopaque Radiopaque. .

Air is most Air is most RadiolucentRadiolucent..

HOUNSFIELD UNIT SCALEHOUNSFIELD UNIT SCALE

Compares Compares attenuationattenuation of of each each tissuetissue through which through which the x-ray beam passes with the x-ray beam passes with the attenuation of the attenuation of WATER.WATER.

Common Indications for Common Indications for IV ContrastIV Contrast in in CTCT

To visualize To visualize blood vesselsblood vessels (Aortic injury, Abdominal Aortic Aneurysm, (Aortic injury, Abdominal Aortic Aneurysm, Pulmonary Embolus)Pulmonary Embolus)

To evaluate for primary or To evaluate for primary or metastatic metastatic tumortumor

To evaluate for To evaluate for infectioninfection or or inflammatoryinflammatory processes processes

To evaluate for To evaluate for traumatictraumatic injury injury

RLQ pain

in a 20 year old male

Appendicitis

Angiography uses intravenous contrast Angiography uses intravenous contrast mediummedium

depts.washington.edu/.../depts.washington.edu/.../brain_aneurysm.htmlbrain_aneurysm.html

rtg.misto.cz

2222RUQPAINUSound Cholelithiasis = Gallstones

ULTRASOUNDULTRASOUND of Deep Venous of Deep Venous ThrombosisThrombosis

Occlusive, LT UEOcclusive, LT UE

2222RUQPAINUSound Cholelithiasis = Gallstones

CONTRAINDICATIONS for CONTRAINDICATIONS for MRI SCANNING:MRI SCANNING:

PacemakersPacemakers, pacing wires (RF current can , pacing wires (RF current can induce cardiac arrhythmias, burns)induce cardiac arrhythmias, burns)Cerebral Cerebral aneurysm clipsaneurysm clips (movement, burns, (movement, burns, induced electrical currents)induced electrical currents)Implants (insulin pumps, Implants (insulin pumps, cochlear implantscochlear implants, , neurostimulator, drug infusion pumps, penile neurostimulator, drug infusion pumps, penile and dental implants)and dental implants)Intra-Intra-orbitalorbital metallic fragmentsmetallic fragments (may deflect in (may deflect in magnetic field, causing injury/blindness), XRay magnetic field, causing injury/blindness), XRay orbits if unsureorbits if unsure

Under InflationUnder Inflation

Over InflationOver Inflation

OpacificationOpacification

Radio opacity is a Radio opacity is a white density on a white density on a filmfilm

Can be a Foreign Can be a Foreign Body, Pneumonia, Body, Pneumonia, Atelectasis, or Atelectasis, or ArtifactArtifact

InfiltrateInfiltrate

Non-specific Lung pathology Non-specific Lung pathology

Can be Pneumonia or AtelectasisCan be Pneumonia or Atelectasis

AtelectasisAtelectasis

Means AirlessnessMeans Airlessness

Usually associated Usually associated with Volume losswith Volume loss

Secondary to Secondary to – mucus plugging mucus plugging

(Asthma), (Asthma), – Foreign BodyForeign Body– Endo-Bronchial lesion Endo-Bronchial lesion

-less likely--less likely-

Which Lung Is Sick?

Pleural EffusionPleural Effusion

Air BronchogramAir Bronchogram

Interstitial Lung DiseaseInterstitial Lung Disease

Lobar PneumoniaLobar Pneumonia

Alveolar lung Alveolar lung DiseaseDisease

Usually Bacterial Usually Bacterial (needs Antibiotics)(needs Antibiotics)

Rule 5Rule 5

Needs to have 2 Needs to have 2 good Diaphragms good Diaphragms on Lateral Viewon Lateral View