Intro to Diagnostic Imaging, Intro to Gross Anatomy 1&2

Conventional X-ray

• Use a form of ionizing radiation to create images of the body for clinical evaluation

• Best for evaluating skeletal structures

Air in Xray

Due to simple molecular structure, most of the xray beams will pass through and reach the detector leading to it appearing as dark regions on xray images

Fat in Xray

It is slightly denser than air but less than soft tissue. Appears darker gray shade on radiographs

Soft tissue in Xray

Soft tissues such as muscles and organs have higher density than fat, allowing them to absorb more x-rays. They appear as lighter grays

Bone in Xray

Denser and contains calcium absorbs a greater amount of xrays compared to soft tissue and fat

Metal in Xray

A very dense structure and contains atoms with heavy atomic weights, which absorb most of the incident x-rays

CAT scan/CT Scan

uses x-ray to produce using different technique but provide more information than conventional x-ray

• Good for tissue evaluation

CAT scan/CT Scan

Housed in a rotating gantry that spins around the patient on a horizontal table

• A helical CT, both rotates and the table moves continuously, creating a spiral data path for faster and smoother images

Magnetic Resonance Imaging(MRI)

Produces images similar to CT but shows greater structural detail

• Excellent for soft tissue evaluation but not for bone

Generation of MRI Images

1. Protons of the body is aligned with the caudal.cranial axis by the magnetic field of the MRI

2. Protons snap back to align with the magnetic field when the

   radio wave ceases. They snap back into alignment with the

   magnetic field, as protons liberate energy.

3. Liberated energy is detected by sensor coils surrounding

   specific regions of the patient’s anatomy (e.g. knee coils,

   head coils).

signal strength

Different tissue appearance is dependent on the ________ when protons snap back to align with the magnetic

field.

Ultrasound

Relies upon high frequency, inaudible and sound arising from a piezoelectric crystal, in a hand held transducer, for the creation of images

acoustic gel

Ultrasound transmission is facilitated by —— which helps to minimize the air-gap

• The returning sound is altered in wavelength and intensity

  and arrives back to the probe after being reflected from

  tissues of different depths beneath the skin.

  ○ The ultrasound machine assigns a pixel brightness to a

  particular tissue

gray scale

• complex, computer driven, algorithm determines the

  characteristics of the returning echoes and displays the

  sound on a

Echoic

Sound is reflected back from the tissue to be

measured by the ultrasound machine.

○ Anatomy appears white when sound waves are

reflected back to the ultrasound transducer.

Anechoic

Sound is not reflected back to the ultrasound

probe from the tissue.

○ Anatomy appears black when sound waves are not

reflected back to the ultrasound transducer.

Hypoechoic

The sound reflected back to the ultrasound

probe is decreased in comparison to some other tissue in

the anatomy being assessed

○ The bile in the gallbladder

Hyperechoic

The sound reflected back is increased in

comparison to some other tissue in the anatomy being

assessed

○ The liver is hyperechoic compared to the bile in the

gallbladder.

Doppler principle

Principle which is utilized by the ultrasound to analyze the flowing fluids and determine if there is a frequency shift over the length of a structure

• Color can also be applied

• BART

  • Blue away, Red towards

Convex/Curved transducer

ultrasound transducer that is Optimal for abdominal and obstetric imaging,

Linear probes

Ultrasound transducer that is Best adapted to vascular and small superficial structures (i.e. thyroid)

Long, wand-shaped ultrasound transducer

Can reach the gland via the rectum (endo-cavitary

probe).

• Can be used for intra-vaginal image acquisition for

  the assessment of female pelvic anatomy (i.e.

  uterus, endometrium, and ovaries).

Higher frequency

Characteristic for transducer: Limited depth of field but provide better image

resolution of the near field anatomy

Lower Frequency

• Best for deep tissue imaging

  ■ Do not provide imaging details of the subcutaneous

  tissues

X-Axis (Horizontal / Transverse)

Paired axis with sagittal plane

Y-Axis (Vertical)

Paired axis with Horizontal plane

Z-axis(Antero-posterior)

Paired axis with coronal plane

Hyperextension:

Extension beyond the neutral position

• Can occur in the shoulder, hip wrist and neck

Dorsiflexion

Foot and toes are off the ground

Plantar flexion

Bends the foot or toe towards the ground

■ Similar to standing on tiptoes

Abduction and adduction

Movement that generally occur in the coronal and z axis

Trunk and neck

Lateral flexion occurs in which parts

Ulnar deviation

deviation: hand and fingers move to the ulnar

side (pinky side)

Radial deviation

hand and fingers move to the radial

side (thumb side)

Inversion

sole of the foot faces towards the median

plane

Eversion

sole of the foot faces away from the median

plane

Circumduction

movement that involves sequential flexion,

abduction, extension, and adduction of the extremity

Internal rotation

External rotation

Protraction and retraction

Movements in the temporomandibular joint and scapula on the thoracic wall

Opposition

Movement of the pad of the 1st digit of the thumb to the pad of other digits

Coronal plane

Plane of the thumb when the Movement is flexion/extension

Sagittal plane

lane of the thumb when the Movement is Abduction/Adduction

Plane: Sagittal

Axis:X-axis

Movements: Flexion/Extension

Elbow/Knee

Plane: Horizontal

Axis:Y-axis

Movements: Rotation of one bone around another

Top of the neck

Plane: Multiple PLanes

Axis: Multiple Axes

Movements: Flexion/Extension, Abduction/Adduction, Internal/External Rotation

Shoulder/Hip

Plane: Coronal and SAgittal planes

Axis: Z and X-axis

Movements: Flexion/Extension, Abduction/Adduction, Circumduction

Saddle Joint

Plane: Coronal and SAgittal planes

Axis: Z and X-axis

Movements: Flexion/Extension, Abduction/Adduction, Circumduction

Condyloid Joint

Ipsilateral

Laterality meaning same side

Contralateral

Laterality meaning opposite side

Bilateral

Laterality meaning paired; both sides

Unilateral

Laterality meaning one side

size, shape, border, consistency, mobility and laterality/location

Creating a correct anatomical description

Consistency

Soft, firm, hard

Border

Smooth or irregular

size

cm

shape

if its round or oval

Medical record

Immortalized version of what happened

on the day of physical examination.

SEE

Observe the symptom or sign. Identify what is

actually present before interpreting it.

SAY

Describe it with standard anatomical and

examination terminology.

DECIDE

Use location and distribution to narrow the

differential diagnosis.

DO

Choose the next examination, investigation,

procedure, or management step safely.

Site & Side, Region & Depth, Landmark relation, Distribution and radiation

A clinically useful description should answer:

History

— A symptom without a precise location remains

broad. Localization converts a complaint into an anatomical

problem.

Physical examination

A sign without a landmark is

difficult for another examiner to reproduce or compare.

Procedure/management

An intervention without

a map risks the wrong site, wrong layer, wrong structure, or

injury to adjacent anatomy.

Localization error in the history

An error which propagated downstream which led to attention directed to the wrong organ system

Imprecise examination description

An error which propagated downstream which led to the next clinician who cannot reproduce the finding

Incorrect laterality

An error which propagated downstream to the wrong side investigation, procedure and treatment

Failure to appreciate anatomical variation

An error which propagated downstream which led to the increased procedural or operative injury

Poor contemporaneous documentation

An error which propagated downstream which led to weak continuity of care and weak medico-legal defensibility

Patient’s perspective

The laterality(R & L) always refer to the —— not the examiners

Supine

Face upward

Lateral decubitus

Face downward

Trendelenburg

Head-down tilt/ semi prone

Lithotomy

Hips/knees flexed’ thighs abducted