1

The Basics

1

2

Sound

11

Sound Waves

11

Acoustic Variables

12

Acoustic Parameters

12

In-Phase and Out-of-Phase Waves

14

Review: Sound

16

3

Describing Sound Waves

19

Period

20

Frequency

21

Three "Bigness" Parameters

27

Wavelength

33

Propagation Speed

36

Review: Describing Sound Waves

41

4

Describing Pulsed Waves

47

Pulse Duration

49

Spatial Pulse Length

51

Pulse Repetition Period

53

Pulse Repetition Frequency

56

Duty Factor

60

Parameters That Describe Both Pulsed and Continuous Waves

64

Review: Pulsed Waves

65

5

Intensities

69

Measuring and Reporting Sound Beam Intensity

70

Spatial Considerations

70

Temporal Considerations

71

Combining Spatial and Temporal Factors

72

The "Ten Commandments" of Intensity

74

6

Interaction of Sound and Media

75

Decibels (dB)

77

Attenuation

80

Attenuation Coefficient

84

Reflection and Transmission

88

Impedance

88

Summary: Reflection, Transmission, and Refraction

104

Review: Attenuation & Reflection

106

7

Range Equation

107

Time-of-Flight or Go-Return Time

107

Review: Range Equation

111

8

Transducers

113

Basic Transducer Construction

114

Transducer Frequencies

122

Review: Transducers

126

9

Sound Beams

129

Shape of a Sound Beam

130

Anatomy of a Sound Beam

130

Determining Focal Depth

135

Sound Beam Divergence

139

Spherical Waves

142

Huygens' Principle

142

Review: Sound Beams

143

10

Axial and Lateral Resolution

145

Axial Resolution

145

Lateral Resolution

151

Focusing

154

11

Display Modes

159

1. A-mode-Amplitude

159

2. B-mode-Brightness

161

3.M-mode-Motion

162

12

Two-Dimensional Imaging

165

Mechanical Transducer

167

Linear Phased Arrays

169

Annular Phased Arrays

178

Linear Sequential Arrays

180

Vector Arrays

186

Slice Thickness or Elevational Resolution

188

13

Real-Time Imaging

197

Temporal Resolution

198

Imaging Depth

200

Number of Pulses per Image

201

14

Pulsed Echo Instrumentation

215

Pulser

217

Beam Former

221

Receiver

223

Output Power vs. Receiver Gain

235

Review: Pulsed Echo Instrumentation

236

15

Displays and Image Processing

239

Display Controls

240

Analog and Digital image Data

247

Magnification

250

Coded Excitation

253

Spatial Compounding

254

Frequency Compounding

255

Edge Enhancement

255

Persistence

256

Fill-in Interpolation

257

Emerging Technology: Elastography

258

PACS and DICOM

259

Recording and Archiving Techniques

260

Review: Displays and Image Processing

261

16

Dynamic Range

265

Dynamic Range of System Components

266

Number of Choices

268

17

Harmonics and Contrast Agents

269

Fundamental and Harmonic Images

270

Tissue Harmonics

272

Pulse Inversion Harmonics

275

Contrast Agents

278

Contrast Harmonics

278

18

Hemodynamics

285

Flow

286

Laminar vs. Turbulent

287

Energy Gradient

289

Forms of Energy

289

Energy Losses in the Circulation

290

Stenosis

292

Bernoulli's Principle

293

Pressure-Flow Relationships

294

Ohm's Law

294

Venous Hemodynamics

295

Hydrostatic Pressure

296

Breathing and Venous Flow

300

19

Doppler

303

Speed vs. Velocity

305

The Doppler Equation

306

Bidirectional Doppler

311

Continuous Wave Doppler

312

Pulsed Wave Doppler

314

Aliasing

315

Color Flow Doppler

325

Doppler Artifacts

334

Spectral Analysis

335

20

Optimizing Doppler Imaging

341

Normal Incidence

342

Color Doppler Gain

344

Spectral Doppler Gain

346

Aliasing

347

Flow Reversal vs. Aliasing

348

Wall Filter

351

Wall Filter vs. Increasing Scale

354

21

Artifacts

355

Image Characteristics

356

Basic Assumptions of Imaging System

356

Reverberation

357

Comet Tail

358

Shadow

359

Enhancement

361

Mirror Image

363

Speed Error

364

Lobes

366

Refraction

368

Slice Thickness

369

Lateral Resolution

370

Axial Resolution

370

Review: Artifacts

376

22

Quality Assurance

379

Requirements

380

Objective vs. Subjective Standards

381

Tissue Equivalent Phantom

382

Doppler Phantom

383

Slice Thickness Phantom

384

Performance Measurements

385

23

Sonographers in the Clinical Setting

391

Major Principles of Medical Ethics

391

Informed Consent

393

Patient-Sonographer Interaction

394

Sonographer-Work Environment Interaction

394

Standard Precautions

396

24

Bioeffects

401

Converting Sound Energy into Heat

403

Risk-Benefit Relationship

405

Study Techniques

407

Mechanisms of Bioeffects

408

Epidemiology

413

Clinical Safety and Prudent Use

414

Electrical Safety

417

Exam Review

423

Index

553