Introduction to Radiographic Imaging
for the EM Clerkship Student
Let's go!
Introduction
Click through this interactive module to learn about different imaging modalities used to diagnose several common pathologies that you will likely see during your EM shifts. Helpful Tip: Every image is enlargable AND is linked to a direct case from Radiopedia! Feel free to explore more on that resource where you can actually scroll through the CTs.
Start course
Table of Contents
MODULES
OBJECTIVES
ASSESSMENT
Objectives
- Become familiar with the basic mechanics behind x-rays and CTs
- Be able to identify normal X-ray and CT imaging
- Be able to identify common pathologies in the Emergency Department on x-ray and CT imaging
Modules
CT
Both!
X-Ray
Module 1. Fundamentals of X-Ray
X-rays are two-dimensional images generated by mapping the attentuation of the x-rays as they pass through the body. Therefore different tissues will produce different densities on imaging. The higher the density, the lighter it appears on x-ray.
Air
Fat
Soft Tissue
Lowest Density
Highest Density
Bone
Landmarks on a Normal Wrist X-Ray
Hover over each marker to see reveal each label!
Wrist x-rays are commonly used for wrist injuries following trauma. Use a systematic approach: work proximally and move distally, looking at structures on both views:- distal ulna
- lateral alignment
- scaphoid and other carpal bones
- metacarpals
A 34 year old male presents to CIA with right wrist pain following a fall
Upon further questioning, he says that he fell on an outstretched hand trying to catch himself. He does not have any past medical history and does not take any medications at home.
His vitals are stable
On exam, he has focal tenderness over the anatomical snuffbox
You order a wrist x-ray which comes back as the image here.
Click the image!
Click for diagnosis!
Other Common Extremity X-rays
Click each sticky note to see the image and learn more!
Femoral neck fracture
Trimalleolar fracture
Tibial plateau fracture
Osteoarthritis of the hip
Module 2. Fundamentals of CT
Computed tomography (CT) uses x-rays to create cross-sectional images of the body. The x-ray emiter rotates around the patient and detector in order to generate images using measurements of the transmission of x-ray through the body section. CT numbers are presented in Hounsfield Units (HU) to reflect the different x-ray densities in the human body:
Considerations for CT:
- Radiation exposure
- Allergy to contrast or iodine
- Patients with renal insufficiency
- Pregnant patients
- Claustrophobia
Landmarks on a Normal CT Abdomen: Different Perspectives
Click each CT to reveal more about each view
A 65 year old male presents to the ED with severe back pain
Upon further questioning, he has a 25 pack year smoking history. He states that he was also told he has high blood pressure but has not seen a provider in years.
He is hypertensive but otherwise stable vitals.
On exam, there is a midline pulsatile abdominal mass and he has tenderness to palpation. He also has diminished pedal pulses.
You order an adbominal CT which comes back as the image here.
Click the image!
Click for diagnosis!
Other Common Abdominal CTs
Click each chief complaint to see more
Patient with jaundice, abdominal distension, and history of chronic EtOH use
Patient with acute lower abdominal pain radiating to the right side
BUT, you will often order both types of imaging:
Walk through each case below
A 55 year-old male presents to the ED with severe flank pain and urinary urgency
A 42-year old female presents to the ED with colicky abdominal pain, nausea, and vomiting
A 42-year old female presents to the ED with colicky abdominal pain, nausea, and vomiting
She has had multiple episodes of bilious emesis but denies any bowel movements of flatus for the last 24 hours. Her medical history is only notable for a Cesarean section 3 years ago.
Her vitals are stable
Physical exam is notable for abdominal distension and high-pitched bowel sounds on auscultation.
You order an abdominal x-ray which comes back as the image here.
Click the image!
Click to order CT!
Click for diagnosis!
A 55 year-old male presents with severe flank pain
Upon further questioning, he states that the flank pain is more left sided and radiates to his groin. He has a history of kidney stones and states that the pain usually comes and goes but it is now constant.
He has a fever and is slightly hypertensive but otherwise stable vitals.
On exam, he is restless in the room and has severe CVA tenderness.
Click the image!
You order an ABDOMINAL x-ray which comes back as the image here.
Click to order CT!
Click for diagnosis!
Post-Test
Please complete the post-test below only after having gone through the entire module.
Click Here
Course completed!
We hope this information will be useful for you throughout your clerkships! 😊 We will send out a survey asking about your experience and any feedback at the end of your rotation. Please be sure to fill that out, as it will be integral to evaluating the impact of this module!
Tibial Plateau Fracture
Most common mechanism of injury involves axial loading. Schatzker classification (I-VI) is use to categorize the mechanism of injury. Fractures of the lateral plateau are more common than the medial plateau. Lipohemarthrosis should be present on x-ray - escape of flat and blood from bone marrow into the joint, causing a fat-fluid level. Therapy: reduction of fraction and early mobilization.
Axial View
For orientation, the image is produced as you would "see" it from the patient's feet while the patient is lying supine. Note the hyperintensity of the fluid inside the bowel. This is due to the oral contrast given to the patient prior to the CT.
Carpal Bones
You should be able to trace 3 carpal arcs on a normal x-ray as shown. Intercarpal joint spaces should be equal as well. The scaphoid bone is the most commonly injured carpal bone. Be mindful of the risk of avascular necrosis when you see one!
Check Lateral Alignment
You should be able to draw a straight line from the distal radius, through the lunate, to the capitate. This can help you determine if there is angulation of a distal radius fracture or carpal dislocation.
Cirrhosis
Progressive fibrosis of liver causing organ dysfunction Clinical presentation is secondary to complications of portal hypertension: ascites, jaundice, hepatic encephalopathy, gastroesophgael varices, transudative pleural effusion, thrombocytopenia Treatment is largely supportive All cirrhotic patients should receive vaccinations for hepatitis A, hepatitis B, and pneumonia
Click here for a coronal view
Left-Sided Nephrolithiasis
Development of stones within the urinary tract. Risk factors: low fluid intake, family history, mecations, male gender, UTIs, dietary factors Calcium stones are the most common - account for 80-85% of urinary stones Clinical features: renal colic, hematuria, nausea, and vomiting Treatment: pain management, IV fluids; stones usually pass without surgical intervention (lithotripsy)
Appendicitis
Inflammation and infection of the appendicial lumen due to obstructionClassic presentation
- Dull periumbilical pain with migration to sharp right lower quadrant pain
- Nausea, vomiting
- Anorexia
- Fever
Treatment: IV antibiotics with anaerobic and gram-negative coverage, NPO, IV fluids, +/- surgical intervention
Click here for a coronal view
Coronal View
This view shifts anterior to posterior and reflects how we would look at the patient if they were standing in front of us. Coronal views develop a mirror image of the patient's anatomy.
Trimalleolar Fracture
Fracture of the ankle involving the lateral malleolus, medial malleolus, and the distal part of the tibia (which all form the talus bone of the foot). Often associated with injury to the ligaments. Treatment: open reduction and internal fixation usually required Important to obtain multiple views!
Frontal view
Lateral view
Small Bowel Obstruction (SBO)
In SBO, gas and fluid build up proximal to the obstruction causing dilation of the bowel and increased motility in attempt to overcome the obstruction, causing high-pitched bowel sounds. Most common cause in the US is adhesions from prior surgery. The most common cause worldwide is hernias. Differentials include: gastroenteritis, ileus, large bowel obstruction, and acute mesenteric ischemia Be on the look out for surgical scars and/or presence of hernias on physical exam. Imaging will show dilated loops of small intestine with air fluid-levels. Initial management includes fluid resuscitation, nasogastric tube decompression, +/- surgery.
Osteoarthritis of the Hip
Degeneration of the cartilage. On x-ray, you will often see narrowing of the joint space, changes in the bone, and formation of bone spurs. Nonsurgical management involves lifestyle modficiations, physical therapy, and medications to maange pain. Surgical intervention can involve total hip replacement, hip resurfacing, or osteotomy.
Abdominal Aortic Aneurysm!
Abnormal dilation of the abdominal aorta. Most are asymptomatic unless they or rupture, and thus many are found incidentally on imaging. Signs of rupture on imaging:
- Retroperitoneal hematoma
- Contrast extravasatiom from aorta into retroperitoneum
- Para-aortic fat stranding
Aneurysm >5.5mm requires urgent repair. Asymptomatic aneurysms <5.5mm can be surveilled annually with ultrasound.
Scaphoid Fracture!
Fracture in one of the small bones of the wrist. Most common after a fall onto an outstretched hand. Clinical symptoms include localized pain to radial aspect of wrist, swelling, decreased grip strength, decreased range of motion Treatment consists of splint or cast and pain management.
Scaphoid
Capitate
Triquetrum
Lunate
Radius
Ulna
Femoral Neck Fracture
In young patients, these fractures are often caused by high-velocity traumas. In older patients, often see these fractures with low energy falls. Recommended x-ray view: AP, cross-table lateral or full-length femur Increased risk of avascular necrosis due to disruption of blood supply. Treatment is generally operative.
EM Imaging Module
JASMINE LEE
Created on September 23, 2024
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Transcript
Introduction to Radiographic Imaging
for the EM Clerkship Student
Let's go!
Introduction
Click through this interactive module to learn about different imaging modalities used to diagnose several common pathologies that you will likely see during your EM shifts. Helpful Tip: Every image is enlargable AND is linked to a direct case from Radiopedia! Feel free to explore more on that resource where you can actually scroll through the CTs.
Start course
Table of Contents
MODULES
OBJECTIVES
ASSESSMENT
Objectives
Modules
CT
Both!
X-Ray
Module 1. Fundamentals of X-Ray
X-rays are two-dimensional images generated by mapping the attentuation of the x-rays as they pass through the body. Therefore different tissues will produce different densities on imaging. The higher the density, the lighter it appears on x-ray.
Air
Fat
Soft Tissue
Lowest Density
Highest Density
Bone
Landmarks on a Normal Wrist X-Ray
Hover over each marker to see reveal each label!
Wrist x-rays are commonly used for wrist injuries following trauma. Use a systematic approach: work proximally and move distally, looking at structures on both views:- distal radius
- distal ulna
- lateral alignment
- scaphoid and other carpal bones
- metacarpals
A 34 year old male presents to CIA with right wrist pain following a fall
Upon further questioning, he says that he fell on an outstretched hand trying to catch himself. He does not have any past medical history and does not take any medications at home.
His vitals are stable
On exam, he has focal tenderness over the anatomical snuffbox
You order a wrist x-ray which comes back as the image here.
Click the image!
Click for diagnosis!
Other Common Extremity X-rays
Click each sticky note to see the image and learn more!
Femoral neck fracture
Trimalleolar fracture
Tibial plateau fracture
Osteoarthritis of the hip
Module 2. Fundamentals of CT
Computed tomography (CT) uses x-rays to create cross-sectional images of the body. The x-ray emiter rotates around the patient and detector in order to generate images using measurements of the transmission of x-ray through the body section. CT numbers are presented in Hounsfield Units (HU) to reflect the different x-ray densities in the human body:
Considerations for CT:
Landmarks on a Normal CT Abdomen: Different Perspectives
Click each CT to reveal more about each view
A 65 year old male presents to the ED with severe back pain
Upon further questioning, he has a 25 pack year smoking history. He states that he was also told he has high blood pressure but has not seen a provider in years.
He is hypertensive but otherwise stable vitals.
On exam, there is a midline pulsatile abdominal mass and he has tenderness to palpation. He also has diminished pedal pulses.
You order an adbominal CT which comes back as the image here.
Click the image!
Click for diagnosis!
Other Common Abdominal CTs
Click each chief complaint to see more
Patient with jaundice, abdominal distension, and history of chronic EtOH use
Patient with acute lower abdominal pain radiating to the right side
BUT, you will often order both types of imaging:
Walk through each case below
A 55 year-old male presents to the ED with severe flank pain and urinary urgency
A 42-year old female presents to the ED with colicky abdominal pain, nausea, and vomiting
A 42-year old female presents to the ED with colicky abdominal pain, nausea, and vomiting
She has had multiple episodes of bilious emesis but denies any bowel movements of flatus for the last 24 hours. Her medical history is only notable for a Cesarean section 3 years ago.
Her vitals are stable
Physical exam is notable for abdominal distension and high-pitched bowel sounds on auscultation.
You order an abdominal x-ray which comes back as the image here.
Click the image!
Click to order CT!
Click for diagnosis!
A 55 year-old male presents with severe flank pain
Upon further questioning, he states that the flank pain is more left sided and radiates to his groin. He has a history of kidney stones and states that the pain usually comes and goes but it is now constant.
He has a fever and is slightly hypertensive but otherwise stable vitals.
On exam, he is restless in the room and has severe CVA tenderness.
Click the image!
You order an ABDOMINAL x-ray which comes back as the image here.
Click to order CT!
Click for diagnosis!
Post-Test
Please complete the post-test below only after having gone through the entire module.
Click Here
Course completed!
We hope this information will be useful for you throughout your clerkships! 😊 We will send out a survey asking about your experience and any feedback at the end of your rotation. Please be sure to fill that out, as it will be integral to evaluating the impact of this module!
Tibial Plateau Fracture
Most common mechanism of injury involves axial loading. Schatzker classification (I-VI) is use to categorize the mechanism of injury. Fractures of the lateral plateau are more common than the medial plateau. Lipohemarthrosis should be present on x-ray - escape of flat and blood from bone marrow into the joint, causing a fat-fluid level. Therapy: reduction of fraction and early mobilization.
Axial View
For orientation, the image is produced as you would "see" it from the patient's feet while the patient is lying supine. Note the hyperintensity of the fluid inside the bowel. This is due to the oral contrast given to the patient prior to the CT.
Carpal Bones
You should be able to trace 3 carpal arcs on a normal x-ray as shown. Intercarpal joint spaces should be equal as well. The scaphoid bone is the most commonly injured carpal bone. Be mindful of the risk of avascular necrosis when you see one!
Check Lateral Alignment
You should be able to draw a straight line from the distal radius, through the lunate, to the capitate. This can help you determine if there is angulation of a distal radius fracture or carpal dislocation.
Cirrhosis
Progressive fibrosis of liver causing organ dysfunction Clinical presentation is secondary to complications of portal hypertension: ascites, jaundice, hepatic encephalopathy, gastroesophgael varices, transudative pleural effusion, thrombocytopenia Treatment is largely supportive All cirrhotic patients should receive vaccinations for hepatitis A, hepatitis B, and pneumonia
Click here for a coronal view
Left-Sided Nephrolithiasis
Development of stones within the urinary tract. Risk factors: low fluid intake, family history, mecations, male gender, UTIs, dietary factors Calcium stones are the most common - account for 80-85% of urinary stones Clinical features: renal colic, hematuria, nausea, and vomiting Treatment: pain management, IV fluids; stones usually pass without surgical intervention (lithotripsy)
Appendicitis
Inflammation and infection of the appendicial lumen due to obstructionClassic presentation
- Dull periumbilical pain with migration to sharp right lower quadrant pain
- Nausea, vomiting
- Anorexia
- Fever
Treatment: IV antibiotics with anaerobic and gram-negative coverage, NPO, IV fluids, +/- surgical interventionClick here for a coronal view
Coronal View
This view shifts anterior to posterior and reflects how we would look at the patient if they were standing in front of us. Coronal views develop a mirror image of the patient's anatomy.
Trimalleolar Fracture
Fracture of the ankle involving the lateral malleolus, medial malleolus, and the distal part of the tibia (which all form the talus bone of the foot). Often associated with injury to the ligaments. Treatment: open reduction and internal fixation usually required Important to obtain multiple views!
Frontal view
Lateral view
Small Bowel Obstruction (SBO)
In SBO, gas and fluid build up proximal to the obstruction causing dilation of the bowel and increased motility in attempt to overcome the obstruction, causing high-pitched bowel sounds. Most common cause in the US is adhesions from prior surgery. The most common cause worldwide is hernias. Differentials include: gastroenteritis, ileus, large bowel obstruction, and acute mesenteric ischemia Be on the look out for surgical scars and/or presence of hernias on physical exam. Imaging will show dilated loops of small intestine with air fluid-levels. Initial management includes fluid resuscitation, nasogastric tube decompression, +/- surgery.
Osteoarthritis of the Hip
Degeneration of the cartilage. On x-ray, you will often see narrowing of the joint space, changes in the bone, and formation of bone spurs. Nonsurgical management involves lifestyle modficiations, physical therapy, and medications to maange pain. Surgical intervention can involve total hip replacement, hip resurfacing, or osteotomy.
Abdominal Aortic Aneurysm!
Abnormal dilation of the abdominal aorta. Most are asymptomatic unless they or rupture, and thus many are found incidentally on imaging. Signs of rupture on imaging:
- Retroperitoneal hematoma
- Contrast extravasatiom from aorta into retroperitoneum
- Para-aortic fat stranding
Aneurysm >5.5mm requires urgent repair. Asymptomatic aneurysms <5.5mm can be surveilled annually with ultrasound.Scaphoid Fracture!
Fracture in one of the small bones of the wrist. Most common after a fall onto an outstretched hand. Clinical symptoms include localized pain to radial aspect of wrist, swelling, decreased grip strength, decreased range of motion Treatment consists of splint or cast and pain management.
Scaphoid
Capitate
Triquetrum
Lunate
Radius
Ulna
Femoral Neck Fracture
In young patients, these fractures are often caused by high-velocity traumas. In older patients, often see these fractures with low energy falls. Recommended x-ray view: AP, cross-table lateral or full-length femur Increased risk of avascular necrosis due to disruption of blood supply. Treatment is generally operative.