CSD Abdominal CT Scan Workshop

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Questions and Answers

What is the primary advantage of using intravenous contrast in a CT scan?

It helps to visualize the digestive system.

It minimizes the risk of contrast-related reactions.

It enhances the visibility of blood vessels and specific tissues. (correct)

It identifies calcifications, stones, and fractures.

Which type of contrast is used to visualize the digestive system?

Intravenous iodine-based

Oral barium-based

Rectal contrast

All of the above (correct)

Which structural elements are NOT typically evaluated in an abdominal CT scan?

Bones

Brain (correct)

Blood vessels

Abdominal wall

What is the purpose of using a systematic approach when reviewing an abdominal CT scan?

To minimize the risk of missing small changes or incidental findings. (A) Signup and view all the answers

What is the main advantage of a non-contrast CT scan compared to a contrast-enhanced CT scan?

It is less expensive and has a lower risk of complications. (B) Signup and view all the answers

Which of the following clinical scenarios would most likely necessitate the use of contrast-enhanced CT scan?

Evaluation of suspected liver lesions. (A) Signup and view all the answers

What are the three primary viewing planes used in CT scans?

Axial, Coronal, Sagittal (C) Signup and view all the answers

What is the MAIN reason for using oral contrast in a CT scan?

To better visualize the stomach, intestines, and other parts of the digestive tract. (A) Signup and view all the answers

What type of images are most commonly used in clinical practice for abdominal CT scans?

Axial (A) Signup and view all the answers

What is the Hounsfield Unit (HU) value for water?

0 (A) Signup and view all the answers

Which of the following tissues would have a negative Hounsfield Unit value?

Air (D) Signup and view all the answers

What happens to the intensity of an X-ray beam as it passes through tissues during a CT scan?

It decreases (A) Signup and view all the answers

Which of the following is NOT a potential use of CT scans?

To measure blood pressure (A) Signup and view all the answers

What term describes tissues that are denser than water on a CT scan?

Hyperdense (D) Signup and view all the answers

Which of the following structures would appear brightest on a CT scan?

Bone (D) Signup and view all the answers

Which of the following is NOT considered an indication for CT scanning?

To determine the patient's blood type (A) Signup and view all the answers

What are the primary advantages of a CT scan over a conventional X-ray?

CT scans provide a higher resolution image, revealing intricate details of multiple structures. (D) Signup and view all the answers

Which of the following statements accurately reflects the development of CT scans?

The initial name of the CT scan was 'computer axial tomography' due to the table's movement after each axial image. (A), The primary developers of the CT scanner were Allan Macleod Cormack and Godfrey Hounsfield. (B) Signup and view all the answers

What does the acronym 'CT' stand for in the context of medical imaging?

Computerized Tomography (E) Signup and view all the answers

How do CT scans generate detailed images?

By using a series of X-rays rotated around a specified body part and generating computer-processed cross-sectional images. (E) Signup and view all the answers

What is a major concern associated with using CT scans?

Potential for biological tissue damage due to ionizing radiation. (D) Signup and view all the answers

How does the radiation dose of a CT scan compare to a conventional X-ray?

CT scans typically involve a significantly higher radiation dose compared to X-rays. (D) Signup and view all the answers

Which of the following is NOT a benefit of a CT scan?

Minimal to no radiation exposure compared to conventional X-rays. (D) Signup and view all the answers

According to the content, what percentage of the population's medical radiation is attributed to CT scans?

50% (B) Signup and view all the answers

Which of the following structures is NOT part of the peritoneal cavity?

Spleen (A) Signup and view all the answers

Which hollow organ is part of the large intestine?

Cecum (B) Signup and view all the answers

Which abdominal blood vessel supplies the intestines with blood?

Celiac Trunk (A) Signup and view all the answers

Which of these is NOT classified as a solid abdominal organ?

Stomach (C) Signup and view all the answers

What is the primary function of the peritoneal recesses?

Facilitate organ mobility (B) Signup and view all the answers

Which part of the small intestine directly connects to the cecum?

Ileum (C) Signup and view all the answers

Which artery is NOT typically associated with the abdominal blood supply?

Radial Artery (C) Signup and view all the answers

Which of the following structures is classified as an omentum?

Both A and B (D) Signup and view all the answers

Study Notes

Abdominal CT Scan Workshop

This workshop covers abdominal CT scans, a radiological imaging technique.
The workshop was led by Dr. Andres Aranda, MD, a nephrologist.
The workshop's block is 9.

Objectives

Review basic CT scan principles.
Recall CT scan advantages over X-rays.
Understand different views in abdominal CT scans.
Review non-contrast vs. contrast CT scan advantages and disadvantages.
Recall structures assessed in abdominal CT scans.
Follow a checklist for abdominal CT scan assessment.

CAT Scan Basics

CT scans use X-rays rotated around a patient.
Computer processing creates cross-sectional images.
CAT scan (Computer Axial Tomography) was initial name used.

History

CT scans (computed tomography): a radiological imaging technique.
Developed by Allan MacLeod Cornmack & Godfrey Hounsfield.
Awarded the Nobel Prize in Physiology or Medicine (1979).
First installed 1974.
X-ray beams rapidly rotate around the subject to create images.

CT Scan

Essentially an X-ray study, producing cross-sectional images of the body.
Detailed examination of bones, organs, blood vessels and tissues is possible.
Low-dose CT scans (10 mSv; 10 times that of a standard abdominal X-ray).
CT scans involve ionizing radiation that can cause biological harm.
Has a higher radiation dose than conventional X-rays (50 to 1000 times).
Account for a considerable portion of radiation exposure to the population.
Approximately 50% of medical radiation exposure is from CT scans.

X-Ray vs. CT Scan

X-rays are limited in detail, primarily highlighting bone density.
CT scans offer high-resolution imaging, evaluating soft tissues, organs, and bones comprehensively.

Indications

Utilized in inpatient and outpatient settings for serious illnesses.
Diagnosing or narrowing differential diagnoses.
Cancer screening, staging, and follow-up.
Performing biopsies and assisting surgical procedures.

Imaging

X-ray beams create images based on tissue density.
Tissue density is measured in Hounsfield Units (HUs).
HUs indicate how much X-ray energy a tissue absorbs.

Hounsfield Units (HU)

Attenuation (reduction of X-ray beam intensity) is directly related to the Hounsfield units (HU).
HU values are quantitative measures of tissue density in CT imaging.
Hyperdense tissues have positive HU values (e.g., bone).
Hypodense tissues have negative values (e.g., air).
Isodense tissues have a HU of 0 (e.g., water).

Attenuation

Attenuation is the reduction of X-ray beam intensity as it passes through tissues.
Tissues attenuate X-rays differently depending on their density.
Dense structures (e.g., bones) attenuate more X-rays and appear brighter.
Less dense structures (e.g., air, soft tissue) attenuate fewer X-rays, appearing darker.

Orientation and Views

Axial scans (cross-sectional images) are the most common view.
Other views (sagittal or coronal) can be used as needed.
Axial scans imagine the subject from their feet, with the left side of subject appearing on the right side of the image.

Orientation/Technique

Describes the positioning of the patient during a CT scan.
Shows X-ray generator-detector positioning in relation to the patient.

Views in CT Scan

Axial, coronal and sagittal views are produced to evaluate the subject.
These are used to examine the: heart, liver, major vessels, aorta.

Non-Contrast vs. Contrast Abdominal CT Scan

Non-contrast: Imaging without contrast agents.
Utility: Assessing baseline anatomy, identifying calcifications/fractures, and minimizing contrast risks.
Contrast: Utilizes contrast agents to enhance visibility.
Utility: Improving visualization of the GI tract, blood vessels, and other tissues. Identifying and characterizing lesions comprehensively.

Abdominal Anatomy on Computed Tomography

Images in this modality are used to visualize the anatomy.

Sources

Includes links to resources for further study.

Checklist for Abdominal CT Scan Structural Assessment

Abdominal wall
Bones: Ribs, vertebral column, hip bones
Peritoneal cavity
Solid organs (e.g. liver, spleen, pancreas, suprarenal glands, kidneys)
Hollow organs (e.g. stomach, small intestine, duodenum, jejunum, ileum, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum).
Blood Vessels (e.g. Aorta, celiac trunk, SMA, IMA, IVC, splenic vein, SMV, IMV).

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Description

Join this workshop focused on abdominal CT scans, a vital imaging technique in radiology. Led by Dr. Andres Aranda, MD, participants will review the principles of CT scans, advantages over X-rays, and key assessments for abdominal structures.