ECG Recording Techniques and Devices

ECG Recording

• ECG is recorded using bipolar leads
• 3 electrodes are used with a ground at the right leg: right arm, left arm, and left leg
• Precordial leads (+ esophageal) are used to provide a horizontal planar projection
• The recording technique can be monopolar or bipolar
• Baseline wander is an artifact introduced by electrode placement
• Muscle artifact can occur due to muscle movement

ECG Noise

• Noise can originate from electrode displacement
• SNR (Signal-to-Noise Ratio) is used to quantify the level of noise
• -6dB SNR indicates the signal is weak and masked by noise
• 18dB SNR indicates a strong signal and minimal noise

Electrodes

• ECG electrodes are available in various configurations
• Electrodes can be attached using adhesives or clips

ECG Recording Devices

• ECG recorders are available in home and clinic settings
• The recorders range from multi-channel advanced devices to simpler, portable devices.

Transducers vs Sensors vs Actuators

• Transducer: converts energy from one form to another.
• Sensor: converts a physical parameter into an electrical output signal.
• Actuator: converts electrical energy into a mechanical or physical output.

Sensor Types

• Active sensors: generate electrical power directly in response to a stimulus.
• Passive sensors: require an external voltage source to produce an electrical output signal.

Fiberoptic biosensor

• A sensor that uses fiber optic technology for detecting various biological parameters.

EMG Recording

• Electrodes are used to measure the electrical activity produced by skeletal muscles
• EMG can be recorded using surface or needle electrodes
• Mono- and bipolar electrodes can be used
• The electrical impulses generated by the muscle fibers are detected by the electrodes
• Two main types of electrodes used are surface and needle electrodes
• EMG is used to examine muscle physiology and detect neuromuscular diseases

EMG Recording Electrodes

• Surface electrodes are applied easily, but are more susceptible to noise and interference.
• Needle electrodes are more sensitive, but need trained personnel application and can be uncomfortable.
• Both types of electrodes are essential for understanding muscle activity.

EMG Recording Equipment

• A recording device, typically equipped with an amplifier, is necessary to record EMG signals.
• Signals can be analyzed using a computer and software specifically for EMG analysis.

EMG Signal Processing

• EMG signals can be analyzed to evaluate muscle state, muscle fatigue, and movement patterns.
• Denoising techniques can be used to analyze EMG signal due to movement artifact.

EEG Recording

• EEG is the electrical activity of the brain recorded from the scalp.
• It is used for monitoring brain function, diagnosis of brain disorders, and research purposes.
• EEG signals are measured by placing electrodes on the scalp to detect electrical activity.

EEG Rhythms

• Normal waveforms are classified as α, β, θ, and δ rhythms
• The superposition of these rhythms is recorded during the EEG measurement.

EEG Recording Devices

• EEG devices are used to monitor brain activity and can be used in various research settings and for brain-computer interfaces (BCI).
• EEG data can offer insights into cognitive processes and emotions

QEEG

• QEEG refers to quantitative EEG, a technique that analyzes EEG signals to extract quantitative information, such as power and frequency characteristics of different brain regions.
• QEEG can help with identifying brain abnormalities and changes in brain function.

Brain Imaging

• Brain imaging refers to the use of various techniques to visualize and study the structure and function of the brain.
• Imaging techniques play a crucial role in understanding brain activity and diagnosing neurological disorders.

Medical Imaging

• Medical imaging refers to the use of technologies to create images of the inside of the human body for diagnoses, monitoring, and treatment planning.
• Medical imaging techniques play a critical role in modern healthcare.

Spatial Frequency in Medical Imaging

• Spatial frequency refers to how often image detail changes across space.
• Higher spatial frequency represents finer details.
• Spatial frequency determines the image resolution in a medical image and is critical in image reconstruction.

Nuclear Medicine

• Nuclear medicine is a medical specialty that utilizes radioactive substances called radiopharmaceuticals.
• Nuclear medicine techniques are used to examine various internal body parts, including the brain, heart, bones, and organs.

Gamma Camera

• Gamma camera is a device used in nuclear medicine to detect and image radioactive isotopes injected into the body.
• It is a powerful tool for imaging and studying the structure and functionality of organs and tissues.

Positron Emission Tomography (PET)

• PET is a medical imaging technique that uses a radioactive tracer to image organ and tissue function.
• It is mainly used for diagnosing cancers, heart diseases, and brain disorders.

Ultrasound Imaging

• Ultrasound imaging is a medical procedure that uses high-frequency sound waves to create images of internal organs and tissues.
• It is a versatile imaging method used in various medical specialties.

Ultrasound Transducer

• Ultrasound transducer is the key component of an ultrasound device.
• It functions as both a sound wave emitter and receiver.
• Ultrasound can be used for various medical purposes, including diagnosis, treatment, and monitoring.

Ultrasound A-Mode

• A-mode ultrasound is used to map the distribution of reflected intensity as a function of time.
• It generates peaks that represent tissue discontinuities along the scan axis.
• A-mode is used in ophthalmology to measure corneal thickness.

Real-Time Ultrasound Scan

• Real-time ultrasound is an extension of A-mode.
• Depth is represented on the vertical axis.
• Amplitude of the reflected pulse modulates brightness.
• Time is represented on the horizontal axis.

B-Mode Ultrasound Scan

• B-mode ultrasound combines A-mode information from multiple directions to form a 2D image.
• The amplitude of the reflected signal (echo) modulates the brightness of the image.
• The position of the dot is determined by the time delay of the received echo.
• B-mode images are created by moving a scan bar.

Ultrasound Triplex

• While standard ultrasound is pulsating, triplex ultrasound utilizes a continuous sound wave.
• Doppler systems detect blood velocity by measuring the frequency difference between the transmitted and reflected signals.

3D Ultrasound Scan

• Sound waves are emitted in many angles, not just vertically.
• The return echoes are processed by a computer to reconstruct a 3D volume.
• 3D ultrasound is used in pregnancy and breast ultrasound scanning.

Tomography

• Tomography allows for 3D mapping of internal structures without invasive procedures.
• Excitation of the internal system from the outside generates a response that depends on the internal structure.
• By combining different responses, a map of the interior can be constructed.
• Depending on the excitation method, there are X-ray tomography, magnetic resonance tomography, and ultrasound tomography.
• Other imaging techniques provide a cumulative view of the entire body area.

Explore the fundamentals of ECG recording through this quiz, covering lead configurations, noise management, and electrode types. Understand the various ECG devices and their applications in both home and clinical settings.