basic concepts in diagnostic imaging at version1

8/13/2019 Basic Concepts in Diagnostic Imaging at Version1

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BASIC CONCEPTS INDIAGNOSTIC IMAGING

J.J. Jimenez, M.D.

A. Tamrazi PhD

Carle Clinic Association

University of Illinois College of

Medicine


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Outline

Introduction

X-Rays

Fluoroscopy GI

GU

CT MR

Innovative Modalities


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Modalities Available in

Radiology Plain Film / X-Ray/Mammography

Fluoroscopy

Ultrasound

CT

MRI Nuclear Medicine/Molecular Imaging

Angiography/Interventional


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Relative Cost of Imaging Studies


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Relative Availability of

Diagnostic ImagingTeaching

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Urban

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Suburban

Commun

-ity Hosp

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Rural

Hospital xxxx xxxx xxx xxx x xx x

Plain

Film

Fluoro U/S CT NM MRI Angio-interven-

tional


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X-Rays

Discovered in 1895 and still used today

Most widely performed imaging exam

X Rays are emitted and detected in cassette

Cassette can generate either a film or a

digital image

Films are kept on file or in a digital

archive


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Most Useful Applications for

Plain X-Rays Chest

Musculoskeletal

Abdomen: limited usefulness


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Plain X-Rays

Pros Cons Widely available

Inexpensive

Doesnt requireadvanced technologist

knowledge

Can be performedquickly

Portable

Ionizing Radiation

Relatively insensitive

Requires patientcooperation


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Fluoroscopy

Utilizes X-Rays

Real-time imaging

Utilizes image intensifier

Involves use of contrast agents


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Main Uses of Fluoroscopy

Gastrointestinal Imaging

Genitourinary Imaging

Angiography

Other

Intraoperative

Foreign body removal

Musculoskeletal


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Fluoroscopy

Pros Cons

Widely Available

Inexpensive Functional and

Anatomic

No sedation required

Requires

ingestion/injection ofcontrast

Patient cooperation

Time consuming


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Gastrointestional Fluoroscopy

Esophogram/Barium Swallow

Modified Barium Swallow/Dysphgiagram

Upper GI

Small Bowel Series

Enteroclysis Contrast Enema

Defecography


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Single Contrast vs

Double Contrast Single Contrast

Generally uses just thin Barium

Distends lumen with high density material

Easier for patient/less mucosal detail

Double Contrast/Air Contrast

Thick barium coats lumen

Effervescent tablets ingested to distend lumen with air Produces see-through images with greater mucosal

detail

Greater sensitivity for small lesions, polyps, ulcers


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Single Contrast

Barium Enema

Double Contrast

Barium Enema

Single Contrast vs Double Contrast


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Contrast Materials for GI Exams

Barium Sulfate

Thick: used in double contrast studies

Thin: used in single and double contrast exams

Paste: mod Ba swallow and defogography

Gastrograffin

Full stregnth: rarely used

Dilute


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Gastrograffin Swallow StudyBarrium Swallow Study

Barium vs Gastrograffin


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Barium Sulfate

Most widely used

Better images than gastrograffin

Chalky taste

Peritonitis may develop if perforation

If delayed transit, may form concretions incolon


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Gastrograffin

Water soluble

Foul Taste

Poor mucosal coating Basically used for R/O obstruction

Wont cause peritonitis if perforation

May cause severe chemical pneumonitis if

aspirated Osmotic pressure draws fluid into bowel lumen

Progressive distention in small bowel obstruction

Therapeutic enema in constipation


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Patient Factors in GI Fluoroscopy

Ability to ingest contrast

In order to get high quality images, a relatively largevolume of contrast needs to be ingested fairly quickly

Mobility

Multiple positions required for GI exams, particularlydouble contrast exams.

Limited mobility = less diagnostic images

Weight

Tables have weight limits

Requires maximal radiographic technique and exposureis often suboptimal


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Esophogram or Barium Swallow

Evaluates pharynx and esophagus

Limited evaluation of stomach

Double or Single Contrast

Mucosal contour and Motility


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Modified Barium Swallow

AKA Dysphagiagram and at Carle cookieswallow

Performed with Speech Pathologist Barium administered in various bolus

consistencies ranging from liquid to solid

Evaluates swallowing mechanism Evaluates for aspiration

Performed on videotape


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Modified Barium Swallow


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Upper GI Exam

Evaluates esophagus, stomach and

duodenum

Double or Single Contrast

Can be combined with small bowel series

Largely replaced by endoscopy and cross-

sectional imaging

Fairly insensitive


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Small Bowel Series

Patient drinks 2 cups of thin Ba

Overhead films obtained at routine intervals

The Ba column is followed through until it

reaches the colon

Transit time, mucosal contour, bowel loop

distribution are evaluated.

Insensitive for small masses


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Small Bowel Series


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Small Bowel Enteroclysis

Double Contrast Small Bowel Series

NGT placed at duodenal-jejunal junction

Ba injected followed by methylcellulose See-through appearance to small bowel

Greater sensitivity for small masses and

mucosal lesions Patient discomfort related to NGT and

diarrhea


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Contrast Enemas

Barium or Gastrograffin

Double contrast or single contrast

Generally less sensitive than endoscopy

Requires bowel prep to assess for mucosal

lesions

Requires some element of patient

cooperation

C t t E


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Single Contrast

Barium Enema

Double Contrast

Barium Enema

Contrast Enemas


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Defecogram

Barium paste is inserted into rectum

Patient is asked to defecate under

fluoroscopy

Ano-rectal and pelvic floor dynamics can be

assessed

Rectocele, intussusception, pelvic floor

relaxation, stress incontinence


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Genitourinary Fluoroscopy

Cystogram

Voiding cystourethrogram

Retrograde urethrogram

Hysterosalpingogram


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Cystogram

Usually in adult patients

Looking for tear or intraluminal mass

Catheter placed and bladder filled with

contrast to capacity: usually 300-500 ml.

Spot films obtained when full

Post void film: usually overhead

C


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Cystogram with Intraperitoneal Rupture

Cystogram


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Voiding Cystourethrogram

VCUG Usually in children with history of UTI

Searching for vesicoureteral reflux

In males, evaluate for urethral

abnormalities: posterior urethral valves

Same as cystogram except when full patient

voids under fluoro with spot films


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Retrograde Urethrogram

RUG Male patients

Pelvic Trauma

Post-infectious: STD- looking for stricture

Different techniques

Meatus occluded and contrast injected into

urethra under fluoro

d h


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Retrograde Urethrogram

RUG


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Hysterosalpingogram

Used to evaluate endometrial canal and

fallopian tubes

Infertility and uterine anomalies

Dye injected into cervical os under fluoro

Injection continued with goal to opacify the

fallopian tubes and spill contrast into

peritoneum


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Musculoskeletal Fluoroscopy

Fracture/Dislocation reduction

Hardware placement in the OR

Flexion/Extension views of c-spine

Arthrography

May be performed in conjunction with MRI or

CT

T h i R l t t


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Techniques Relevant to

MSK Radiology

Radiography (routine and specialized

views)

CT MRI

US

Densitometry

Interventional procedures (arthrography,

percutaneous biopsy/vertebroplasty)

MSK R di l


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MRISagittal Knee

T1 Weighted

MSK Radiology

Vertebroplasty

C t d T h (CT)


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Computed Tomography (CT) Cross Sectional imaging modality

Mobile X-ray tube that rotates around a pt

Slices of X-ray transmission data

reconstructed to generate image

Data displayed in multiple window settings(lungs parenchyma, bone, etc.)

Density measurements/Hounsfield Units

analyze chemical component of tissue

HU: -150-0 = fat, 0 = water, 0-20 = serous

fluid, 45-75 = blood,

100-1000 = bone/calcium

CT C t t A t


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CT Contrast Agents

Intravenous contrast---iodinated

Differentiate blood vessels vs. vascular

internal organs

Enteric contrast---barium

Differentiate bowel vs. intra-abdominal

fluid/masses

Rectal contrast

Retrograde urinary bladder contrast

CT A li ti


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CT Applications

Neuro-imaging

-Acute head trauma, acute intracranial

hemorrhage

-Low sensitivity for early ischemic stroke,

intracranial metastatic disease, white matter

degenerative disease

Head and Neck imaging

-Soft tissue of neck, paranasal sinuses, temporal

bone imaging, orbital wall imaging

CT A li ti


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CT Applications

Body Imaging

-Chest, Abdomen, Pelvis (with enteric and

IV contrast)

Pulmonary nodules, Renal Calculi (without

contrast)

Acute appendicitis (with enteric and IV

contrast)

Specialized protocols:

-Liver masses, pancreatic tissue, renal

masses, adrenal masses

CT A li ti


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CT Applications

Acute Abdomen

-decrease rate of false laparotomy procedures

Trauma Spine Imaging (cervical, thoracic,

lumbar)

Other osseous structures (pelvis,

extremities)

Vascular Imaging

-CT angiography--- i.e. coronary arteries


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CT

Axial, with oral contrast in stomach


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CT PET PET/CT

The Po er of CT


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CTA

(CT Angiography)CT Cardiac Imaging

The Power of CT

Magnetic Resonance Imaging (MRI)


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Magnetic Resonance Imaging (MRI)

Multi-planar scanning Without ionizing radiation

Images generated using powerful magnets

and pulsed radio waves passing through thebody

Data from Pts body used to generate image

Field strength of magnets 0.3-3.0 Tesla

MR Contrast Agents


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MR Contrast Agents

Intravenous contrast---Gadolinium chelate-

based contrast agents

Gadolinium is a paramagnetic lanthanide

that is toxic as a free metal

Contrast to evaluate BBB, intracranial

edema and hemorrhage

Novel agents being developed as tagged

Monoclonal antibodies for MolecularImaging

MR Applications


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MR Applications

Neuro-imaging

-Excellent tool due to high soft tissue

contrast resolution

-Abundant water content of CNS allows for

imaging soft intracranial tissue

Head and Neck imaging

-Multi-planar capability allows for monitoring

extent of disease

-Differentiating subtle soft tissue boundaries of

head and neck


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MRI

Axial, T2-Weighted


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MR Applications


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MR Applications

Body Imaging-Thorax: mediastinal, hilar, chest wall

abnormalities

Limited lung imaging due to artifacts New advances in breast imaging

Potentials for cardiac MRI with coronary

MR angiography


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MRI

Breast Imaging

MR Applications


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MR Applications

MSK Imaging- High sensitivity for neoplastic,

inflammatory, and traumatic conditions of

bone and soft tissue- T1-weighted---fluid collections and

abnormalities in fatty marrow

- T2-weighted---lesions in both marrow andsoft tissue


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MRI

Sagittal, T1-Weighted

Innovative Modalities


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Innovative Modalities Constantly evolving face of radiology

New contrast agents for CT and MR Molecular Imaging

- Imaging molecular events---enzymatic

activity, receptor binding, cellular events

Interventional Radiology and Interventional

Neuroradiology

basic concepts in diagnostic imaging at version1

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