learning objectives quizlet

Clinical decision-making

Using patient history, physical examination, and evidence to determine the need for diagnostic imaging.

When the history, systems review, and objective findings indicate additional information is needed to guide diagnosis or treatment.

When should diagnostic imaging be ordered?

When it will not change patient management or when patients are progressing as expected without red flags.

When is imaging NOT recommended?

Benefits of diagnostic imaging

Improves diagnosis, guides treatment, monitors disease progression, and facilitates interdisciplinary care.

Role of imaging in healthcare

Provides objective information to support diagnosis, prognosis, and treatment planning.

Interdisciplinary use of imaging

Physicians order imaging, radiologists interpret it, and other healthcare professionals use the results for patient care.

Primary responsibility of a radiologist

Interpret medical images and communicate findings to the healthcare team.

Role of physical therapists regarding imaging

Recognize indications, identify red flags, and recommend referral when appropriate.

Role of athletic trainers regarding imaging

Recognize injuries requiring imaging and facilitate referral.

Role of nurse practitioners regarding imaging

Order appropriate imaging and integrate findings into patient management.

Role of audiologists regarding imaging

Recommend imaging when structural abnormalities affecting hearing or balance are suspected.

Basic principle of diagnostic imaging

Different imaging modalities interact differently with body tissues to create diagnostic images.

Ionizing radiation

Imaging that uses high-energy radiation capable of removing electrons from atoms (X-ray, CT, fluoroscopy).

Non-ionizing imaging

Imaging that does not use ionizing radiation (MRI and ultrasound).

Radiograph

Two-dimensional image created by passing X-rays through the body.

Electrons strike a metal target producing X-ray photons.

How are X-rays produced?

Different tissues absorb different amounts of X-rays before reaching the detector.

How do X-rays create images?

Radiodensity

Ability of a structure to absorb X-rays.

Radiopaque

Structures that absorb many X-rays and appear white.

Radiolucent

Structures that absorb few X-rays and appear dark.

White.

Bone appearance on X-ray

Gray.

Soft tissue appearance on X-ray

Black.

Air appearance on X-ray

Suspected fracture.

Most common indication for X-ray

Fast, inexpensive, excellent for bone.

Advantages of X-ray

Uses ionizing radiation and provides poor soft tissue detail.

Disadvantages of X-ray

AP, PA, lateral, oblique.

Common X-ray views

AP view

X-ray beam enters anterior and exits posterior.

PA view

X-ray beam enters posterior and exits anterior.

Lateral view

Provides side view of anatomy.

Oblique view

Provides angled visualization of structures.

CT scan

Uses rotating X-ray beams and computer reconstruction to create cross-sectional images.

Trauma, fractures, internal bleeding, stroke, abdominal emergencies.

Best uses of CT

Fast, detailed cross-sectional anatomy, excellent bone imaging.

Advantages of CT

Higher radiation dose than standard X-rays.

Disadvantages of CT

Acute trauma, suspected hemorrhage, unstable patients.

When is CT preferred over MRI?

MRI

Uses magnetic fields and radiofrequency waves to create detailed images.

Ionizing radiation.

MRI does NOT use

Primary function of the MRI magnet

Align hydrogen protons.

Role of radiofrequency pulse in MRI

Temporarily disrupts proton alignment.

How MRI images are formed

Signals released as protons realign are detected and reconstructed into images.

T1-weighted MRI

Fat appears bright; fluid appears dark.

Best use of T1 MRI

Normal anatomy and fat-containing structures.

T2-weighted MRI

Fluid appears bright.

Best use of T2 MRI

Edema, inflammation, and pathology.

Best tissues evaluated with MRI

Brain, spinal cord, muscles, ligaments, tendons, cartilage, discs.

Advantages of MRI

Excellent soft tissue contrast without ionizing radiation.

Disadvantages of MRI

Longer exam time, expensive, contraindicated with some implants.

Contraindications to MRI

Certain pacemakers, ferromagnetic implants, metal fragments.

Clinical indications for MRI

Herniated discs, ligament tears, rotator cuff tears, brain pathology.

PET scan

Uses radioactive tracers to evaluate metabolic activity.

Most common PET tracer

Fluorodeoxyglucose (FDG).

FDG measures

Glucose metabolism.

SPECT scan

Uses gamma-emitting tracers to evaluate physiologic function.

Difference between PET and SPECT

PET has higher resolution and better quantification.

Advantages of PET

Evaluates metabolic activity before structural changes occur.

Disadvantages of PET

Expensive and involves radioactive tracers.

Clinical indications for PET

Cancer staging, treatment monitoring, cardiac viability, inflammatory disease.

Clinical indications for SPECT

Myocardial perfusion, bone scans, seizure localization.

Ultrasound

Imaging that uses high-frequency sound waves.

How ultrasound works

Sound waves reflect off tissues and return echoes to the transducer.

Image brightness in ultrasound

Determined by amplitude of returning echoes.

Image depth in ultrasound

Determined by travel time of sound waves.

Diagnostic ultrasound

Used to visualize anatomy.

Therapeutic ultrasound

Used to promote tissue healing and pain relief.

Advantages of ultrasound

Portable, inexpensive, real-time, no ionizing radiation.

Disadvantages of ultrasound

Operator dependent and cannot penetrate bone or air well.

Best uses of ultrasound

Gallbladder, pregnancy, tendons, muscles, blood vessels, heart.

Ultrasound and brain imaging

Generally not used for adult brain bleeds because sound cannot penetrate the skull.

Doppler ultrasound

Evaluates blood flow.

Echocardiography

Ultrasound of the heart.

Ultrasound in physical therapy

Muscle, tendon, and soft tissue assessment.

Ultrasound in athletic training

Muscle and tendon injuries.

Ultrasound in nursing

Pregnancy, vascular access, bladder assessment.

Ultrasound in audiology

Assessment of neck soft tissues and selected procedures.

Histology

Microscopic study of tissues.

Purpose of histology

Diagnose disease by examining tissue architecture and cellular morphology.

Histologic specimen

Biopsy.

Microbiology

Study of microorganisms causing disease.

Purpose of microbiology

Identify infectious organisms and determine antimicrobial susceptibility.

Examples of microbiology samples

Blood, sputum, urine, wound cultures, CSF.

Gold standard for wound infection

Wound culture.

Best fluid for meningitis diagnosis

Cerebrospinal fluid.

Difference between histology and microbiology

Histology examines tissue structure; microbiology identifies infectious organisms.

Why obtain a biopsy

Determine benign vs malignant tissue or diagnose disease.

Why obtain microbiologic samples

Identify pathogens and guide antibiotic therapy.

Patient advocacy

Recommend appropriate follow-up testing based on examination findings.

Interdisciplinary collaboration

Healthcare professionals work together using imaging and laboratory results to optimize patient care.

Red flags requiring imaging

Progressive neurologic deficits, bowel/bladder dysfunction, unexplained weight loss, suspected fracture, severe trauma, infection, cancer.

Imaging for suspected fracture

X-ray first.

Imaging for rotator cuff tear

MRI.

Imaging for Achilles tendon rupture

Ultrasound or MRI.

Imaging for gallbladder disease

Ultrasound.

Imaging for osteoporosis

DEXA scan.

Imaging for suspected cauda equina syndrome

Emergent MRI.

Imaging for metastatic cancer monitoring

PET scan.

Imaging for internal bleeding in unstable trauma patient

FAST ultrasound.

Imaging for suspected stroke

CT first to rule out hemorrhage.

Imaging for chronic lumbar radiculopathy

MRI.