Ultrasound for Gastric Volume: Clinical Applications and Techniques

Questions and Answers

Qual é a principal característica das técnicas de imagem por ultrassom?

Utilizam ondas sonoras de alta frequência para criar imagens de órgãos e tecidos internos

Por que o ultrassom é considerado uma ferramenta valiosa na avaliação do volume gástrico?

Porque permite visualizar a estrutura interna do estômago e medir seu volume

Como as ondas do ultrassom são capturadas para formar imagens dos órgãos internos?

Elas são refletidas pelo transdutor e convertidas em imagens

Qual é uma aplicação clínica do ultrassom gástrico mencionada no texto?

Avaliação do tempo de trânsito de uma refeição sólida ou líquida através do estômago Signup and view all the answers

Por que o transdutor utilizado para avaliar o volume gástrico normalmente possui uma sonda linear de alta frequência?

Para visualizar a estrutura interna do estômago com mais clareza Signup and view all the answers

Como a ultrassonografia pode ser útil na detecção de obstrução da saída gástrica?

Detectando o esvaziamento gástrico anormal, que pode indicar obstrução da saída gástrica. Signup and view all the answers

Qual fórmula é utilizada para calcular o volume gástrico pelo método elipsoide?

$V = (π/6) × (diâmetro antral (DA) × diâmetro fundico (DF) × DA)$ Signup and view all the answers

O que pode causar o artefato de sombra acústica em ultrassonografia?

Objetos com alta impedância acústica, como lesões calcificadas. Signup and view all the answers

Qual das seguintes situações resulta em um artefato de cauda de cometa na imagem de ultrassom?

Movimento rápido de uma estrutura, como uma onda peristáltica. Signup and view all the answers

Qual é a principal característica dos artefatos de reverberação em ultrassonografia?

São reflexos múltiplos das ondas ultrassônicas. Signup and view all the answers

Study Notes

Ultrasound for Gastric Volume: An In-Depth Exploration

Ultrasound imaging techniques have gained significant importance in the field of medical diagnostics, including assessing the gastric volume. This article delves into the clinical applications of gastric ultrasound, measuring gastric volume with ultrasound, and artifacts of ultrasonography relevant to this assessment.

Ultrasound Imaging Techniques

Ultrasound imaging (ultrasonography) is a non-invasive diagnostic tool that uses high-frequency sound waves to create images of internal organs and tissues. It's a safe, painless, and cost-effective procedure that can be repeated over time to monitor changes. Ultrasound waves are emitted by a transducer, which is placed on the skin's surface. The sound waves penetrate through the body, and the echoes that bounce back are captured by the transducer and converted into images.

For gastric volume assessments, a transducer with a high-frequency linear probe (typically 5–10 MHz) is used to visualize the stomach's internal structure and volume.

Clinical Applications of Gastric Ultrasound

Ultrasound is a valuable diagnostic tool for evaluating the gastric volume and assessing various pathologies, including:

Assessing gastric emptying: Ultrasound can be employed to evaluate the transit time of a solid meal or liquid through the stomach and measure gastric emptying.
Detecting gastric outlet obstruction (GOO): Ultrasound can be used to detect abnormal gastric emptying, which may indicate GOO.
Investigating gastric wall and muscle layer: Ultrasound can help visualize the gastric wall and muscle layers, helping diagnose conditions like gastric wall thickening, gastritis, and gastrointestinal stromal tumors.
Evaluating gastric anatomy: Ultrasound can be used to evaluate the gastric anatomy, such as the presence of diaphragmatic hiatus hernias, gastric varices, and gastric volvulus.

Measuring Gastric Volume with Ultrasound

Ultrasound allows for the qualitative and quantitative assessment of the gastric volume. To measure the gastric volume, a 10-MHz linear probe is placed on the right hypochondrium. The stomach's anterior and posterior walls are assessed in two or three orthogonal views, and the antral diameter and fundic diameter are measured.

The gastric volume can be calculated using one of the following formulas:

Ellipsoid formula: The volume (V) is calculated as V = (π/6) × (antral diameter (AD) × fundic diameter (FD) × AD).
Cylindrical formula: The volume (V) is calculated as V = π × (antral diameter (AD)²/4) × fundic diameter (FD).

Artifacts of Ultrasound Imaging

Artifacts can occur in ultrasound imaging due to a variety of factors, including:

Bone shadow artifacts: Ultrasound waves cannot penetrate through bony structures. As a result, a shadow artifact is created behind the bone.
Acoustic shadow artifacts: Objects with a high-acoustic impedance, such as a calcified lesion, may create a shadow artifact behind the object.
Comet tail artifacts: When a rapidly moving structure, such as a peristaltic wave, is imaged, a comet tail artifact may be created.
Reverberation artifacts: Reverberation artifacts occur when ultrasound waves bounce back from an interface multiple times, creating multiple echoes at the same depth.

In conclusion, ultrasound for gastric volume assessment is a valuable diagnostic tool that can be employed to evaluate gastric emptying, detect gastric outlet obstruction, and assess gastric wall and muscle layers. With a deep understanding of ultrasound imaging techniques, clinical applications, measuring gastric volume, and artifacts of ultrasound, diagnosis and management of gastric disorders can be optimized.