Final Flashcards
Transpyloric plane
Level of L1
Subcostal plane
Level of L3
Transtubercular plane
Level of surface of iliac crest
Midaxillary plane
Divides the body into equal anterior and posterior halves
Propagation speed of ultrasound in soft tissue
1540 m/s
Propagation speed of ultrasound in air
331 m/s
Propagation speed of ultrasound in bone
3000-5000 m/s
How do we characterize a structure?
- compare to surrounding structures/tissue
- evaluate contents
- shape and borders
- is it affecting surrounding structures?
- blood flow?
Low attenuation structures usually represent what echogenicity
Anechoic
Anechoic is AKA
Echofree, echolucent, sonolucent
High attenuation structures usually appear
Echogenic
Complex structure
Both anechoic and echogenic areas
Most complex structures are
Malignant
Hypoechoic is AKA
Echopenic, echopoor
Homogenous
Uniform texture, same echoes throughout, same shade of gray
Types of texture
Smooth, rough, coarse, cobblestone
Increased through transmission occurs below a structure that is
Low attenuation, typically anechoic
Decreased through transmission occurs when sound wave is
Attenuated by a solid or calcified structure
Lesion
Abnormal change in tissue of an organ, usually caused by disease or trauma
Nodule
Abnormal swelling or aggregation of cells in the body
How many lobulations are acceptable
3 or less
What are the only two specialty exams that will grant a technologist the credentials of RDMS
Ob/Gyn and abdominal
The normal thyroid should appear
Homogenous, smooth, Isoechoic
SDMS sets
Code of Ethics and Scope of Practice
AIUM creates/regulates
scanning protocols
ACR creates/regulates
scanning protocols/quality assurance
Assault
threat or unsuccessful attempt to injure another causing fear or immediate harm
Battery
Unlawful touching of another person directly or with an object
False imprisonment
Holding or detaining a patient against his/her will
Negligence
Failure to perform in a reasonable manner or to fulfill the expected standard of care
Code of Ethics Principle 1
To promote patient well-being:
- provide info about purpose/risks etc of exam
- respect patient autonomy
- promote privacy, dignity, comfort
- protect confidentiality
Code of Ethics Principle II
To promote the highest level of competent practice:
- proper education, credentials
- adhere to protocols, practice within scope
- continuing education
Code of Ethics Principle III
To promote professional integrity and public trust:
- truthful and appropriate communication
- respect patient, colleague, and your own rights
- promote equitable care
Vascular technology subspecialties
Interventional and Diagnostic & Therapeutic
SDMS Scope of Practice
“The Diagnostic Ultrasound Professional is an individual qualified by professional credentialing and academic and clinical experience to provide diagnostic patient care services using ultrasound and related diagnostic procedures. The scope of practice of the Diagnostic Professional includes those procedures, acts and processes permitted by law, for which the individual has received education and clinical experience, and in which he/she has demonstrated competency.”
What contributes to patient diagnosis? (4 things)
- lab values
- imaging
- patient history
- symptoms
Borders can be described as
- smooth
- well-defined
- irregular
- ill-defined
- thick
- thin
- angular
- spiculated
- lobulated
Cyst appearance
- anechoic
- well-defined/smooth borders
- enhancement
- homogenous
SALT imaging principles
- size
- shape
- acoustic characteristics
- location
- transmission
What is measured in sagittal
length and height
measurement taken in transverse
width
When soundwave echoes are uniformly spaced, it results in
smooth texture
T or F: Hyperechoic structures usually represent a high density tissue
True
Attenuation
The process of soundwave absorption
Spiculated masses
Always malignant, has center which is origin and pulls surrounding tissue in
Small hyperechoic areas are
microcalcifications
Liver metastases appearance
hypoechoic spots that look like leopard spots
Which two conditions can be diagnosed using compression technique
- Murphy’s sign
- DVT
What are imaging presets?
Optimized settings for certain type of exam, also have associated measurement packages
During transmission transducer converts energy in what way
electrical energy into acoustic energy
During reception, transducer converts energy how
Acoustic energy into electrical energy
Imaging preset types
- ABD: ab & renal
- OB
- GYN
- VAS
- UR (urinary): typically for prostate, sometimes bladder
- SMP: small parts (thyroid, testicles, breast)
- PED
Depth
adjusted up & down, eliminates excess posterior info to better center and see structure of interest
Curved transducer frequency
1-5 mHz
Linear transducer frequency
6-15 mHz
Lower frequency is used for
Better penetration for deep structures
High frequency used for
Better resolution for superficial structures
How can you get better images of the posterior field of view/deeper structures?
Increase depth, decrease frequency
What should you do when scanning a larger patient to get better quality images?
Use the curved transducer and lower frequency
Gain
B
Increases the strength of all electrical signals identically, makes whole image brighter or darker
If vessels are appearing gray in your image how can you improve it
Decrease gain so that they appear anechoic
Time Gain Compensation
- creates uniform brightness from top to bottom
- adjustable from anterior to posterior
- corrects differences in echo strengths caused by attenuation (posterior tends to be darker)
Focal Zone
- where concentration of soundwave strength is sent
- position at or below depth of area of interest
- one focal zone should be used to avoid slowing down system and lowering resolution
- sometimes more than one is used in superficial structures
Dual Screen
- can look at two images side by side, measure and compare measurements
- Sag picture (L & H measurements) on left
- Trans image (width) on right
- R & L buttons above freeze
What happens if you push down on depth button
It will flip the orientation of the image
Trackball
- place measurement calipers
- change color doppler box size
- bottom right of screen tells you what the 4 buttons around trackball will do
Sector width
- rotate depth knob
- narrows field of view & eliminates excess info on sides if you are looking at a small area
- improves frame rate & resolution
Color Doppler
- shows bi-directional flow: one color is flow towards transducer, one color is flow away from
Color Power Doppler
- sensitive for slow flowing/small vessels
- non-directional, just evaluates motion and intensity
Pulsed Wave Doppler
- measures velocity of blood flow
- place gate in middle of vessel
- displays a waveform
Compression (control)
- eliminates all reflections that are not useful to the image, reducing the difference between smallest and largest signal
- keeps signals within operating range
- changes the gray scale
Rejection
- eliminates lowest strength reflections
- affects low level echoes but not bright ones
What do red and blue represent on color doppler
- red: flow toward transducer
- blue: flow away from transducer
What controls are adjustable in post-processing?
- annotate, calipers, gain, TGC
- in more modern machines: zoom and sector width
What is a disadvantage of adjusting zoom and sector width in post-processing?
You do not get the same benefits as using them during live scanning such as better image resolution
Abdominal region of the liver
Right hypochondrium and epigastrium
Abdominal region of the gallbladder
right hypochondrium
Abdominal region of the pancreas
Epigastrium
Abdominal region of the spleen
Left hypochondrium
Abdominal region of the stomach
Mainly in transpyloric plane
Abdominal region of kidneys
- Right kidney more posterior to left
- Hilus mainly in transpyloric plane
Abdominal region of great vessels
- midline of body
- aorta to left of midline
- IVC right of midline
Abdominal region of small intestine
Central portion of abdomen
Abdominal region of large intestine
Periphery of abdomen
Abdominal region of appendix
Right iliac
Abdominal region of bladder, prostate, uterus
Hypogastrium
What is the goal of ergonomics
To increase efficiency and productivity and reduce discomfort and injury
Methods to create a more ergonomic environment
- modifying equipment
- reevaluating tasks
- changing the environment for optimal health & safety
What year did sonography related pain and discomfort surface?
1980
Who conducted a research survey in 1985? Who did it survey and what did it find?
- Marveen Craig
- 100 sonographers with 5-20 years experience
Complaints: - stress/burnout
- visual problems
- infections
- allergies
- electric shock
- muscle strains
What was the most common complaint by sonographers?
Sonographer’s shoulder
What is sonographer’s shoulder?
- includes shoulder, elbow, wrist, thumb
- pain, strain, stiffness, carpal tunnel
- worsened by heavy transducers and cables
What were ultrasound machines like before 1980?
Articulated arm scanner, b-mode machines (images made of dots of different brightness)
How did ultrasound change after 1980?
- real time 2D scanners were introduced
- sonographer’s shoulder declined but only for a decade
When was the Occupational Safety and Health Act passed?
1970
What is a work-related musculoskeletal disorder?
Defined by injuries that result in:
- restricted work
- days away from work
- symptoms for > 7 days
- require medical treatment
What are ultrasound WRMSD caused by? What do they cause?
- Aggravated workplace activities (repeated motions)
- Cause inflammation, swelling, deterioration, degeneration
What percent of workplace injuries are WRMSD?
60%
How many sonographers have a WRMSD?
> 80%
What does awkward posture cause?
Imbalances between moving and stabilizing muscles
Consequence of prolonged, static posture
Compression on spine and soft tissues
Consequence of repetitive head and neck rotation
One set of muscles become stronger and shorter and opposite muscles become weaker and elongated
Asymmetric forces cause
Spinal misalignment
Increased pressure on nerves adjacent to affected muscles can cause
Nerve entrapment syndromes
Tendonitis/tenosynovitis
inflammation of tendon/tendon sheath, typically occur together
Carpal tunnel
entrapment of the median nerve through the carpal bones, caused by repeated flexion/extension of the wrist
Thoracic outlet syndrome
Nerve entrapment occurring at different levels of the thoracic cage, from collarbone to border of ribs
Trigger finger
Inflammation and swelling of the tendon sheath, entraps the tendon & restricts finger motion
Bursitis
Inflammation of shoulder bursa from repetitive motioin
Rotator cuff injury
Repetitive motion causes fraying of rotator cuff muscle tendons, caused by increasing age and repetitive abduction of the arm
Spinal degeneration
Vertebral disc degeneration, caused by bending, twisting, and improper seated posture
Features of modern machines that can help reduce WRMSD
- brakes
- adjustable height control panel
- adjustable height, swivel, tilt monitor
- easily accessible controls
- transducer are not too wide or narrow
- lightweight, thin, flexible transducer cords
- cord hooks
Features of exam tables and chairs that improve ergonomics
Tables:
- adjustable height
- brakes
- stirrups
- drop down compartments for gyn exams
Chairs:
- adjustable height & flexion/extension
- wheels
- narrow (less distance from pt)
Proper transducer grip
- Mild pressure
- Limit excess gel
- Use more of hand and less of fingers (no pinch grip)
- Neutral wrist
- Forearm support (table, patient, etc)
What is the main reason for shoulder pain?
Scanning arm abduction
How to improve scanning arm abduction
- Should be < 30 degrees
- Lower table and raise chair
- As close to pt as possible
When you are not using controls you should
Bring your arm back to your lap
Issues with portable scanning
- lack of space
- tubes, lines, cords, catheters
- patient’s can’t move themselves or are positioned in a particular way
- oversized beds
Solutions to help with portable scanning
- inform main desk before entering room
- ask for help
- rotate sonographers
Liver size
~ 15-17 cm long, 3.5 lbs
What 3 areas of the liver are not covered by peritoneum?
- Bare area
- Fossa for IVC
- Fossa for gallbladder
What is the bare area?
To the right of the IVC, in direct contact with the diaphragm
What is the entire liver enclosed by
Glisson’s capsule (fibrous capsule)
Right lobe of the liver is how much larger than the left
6 times larger
What divides right and left lobes?
- Middle hepatic vein: divides lobes cranially
- Main lobar fissure: divides lobes caudally, gallbladder located within
- Falciform ligament: extrahepatic portion of ligamentum teres, separates right and left lobes at surface of diaphragm
Margins of the caudate lobe
- Ligamentum venosum fissure: divides left lobe anteriorly from caudate lobe posteriorly
- Left portal vein: same as above
- IVC: margin to right lateral of caudate lobe
- Left margin forms the hepatic boundary of the superior region of the lesser sac
- Right margin extends as projection between IVC and portal vein
The right lobe of the liver is divided into anterior and posterior segments by
right intersegmental fissure
Where does the right intersegmental fissure run
from porta hepatis to right hepatic vein
The left lobe is divided cranially to caudally by what 3 things
left hepatic vein, left portal vein, ligamentum teres
Couinaud intersegmental anatomy divides the liver into _______ based on what
8 segments based on blood supply (each segment has its own blood supply)
The ligamentum teres is AKA
round ligament
The ligamentum teres is the remnant of what
fetal umbilical vein which closes after birth
What is patent umbilical vein
When the umbilical vein becomes recanalized due to cirrhosis or portal hypertension
The ligamentum teres is an extension of what
left portal vein
What is the sonographic appearance of ligamentum teres in transverse
an echogenic triangle
What is the falciform ligament? What does it do?
intrahepatic part of ligamentum teres, connects liver to abdominal wall
When is the falciform ligament seen on ultrasound?
When the patient has ascites
What is the ligamentum venosum remnant of?
The fetal ductal venosum
The ligamentum venosum separates what lobes?
left and caudate
The ligamentum venosum communicates with the _____ at the region of the portal vein
ligamentum teres
Main lobar fissure is AKA
interlobar fissure
The main lobar fissure divides
right and left lobes
Main lobar fissure sonographic appearance
Sag: thin, echogenic line from right portal vein to gallbladder fossa
Trans: from gallbladder to IVC
The right intersegmental fissure divides the right lobe into
anterior and posterior segments
The left intersegmental fissure divides the left lobe into
medial and lateral segments
Vascular supply to the liver: how much via portal vein/hepatic artery
portal vein: 80%, nutrient rich
hepatic artery: 20%, oxygen rich
What drains the liver?
hepatic veins, join together and drain into IVC
What enters and exits at the porta hepatis?
Portal vein and hepatic artery enter
CBD exits
The porta hepatis is located on what surface of the liver?
Inferior
The common hepatic artery branches off the _____
celiac axis
The common hepatic artery gives rise to
gastroduodenal artery, supraduodenal artery, right gastric artery
The common hepatic artery divides into what
Right and left branches to supply the right and left lobes
The portal veins bring ______ blood to the liver from
nutrient rich blood from the intestines
The main portal vein originates at the union of what two veins
splenic and superior mesenteric
portal splenic confluence
At the porta hepatis the main portal vein divides into
right and left portal veins
The left portal veins travel ______ into the left lobe
vertically
The right portal veins travel _______ into the right lobe
transversely
Bile ducts and portal veins normally travel
parallel to each other
What is the collagen content of the hepatic vs portal veins
hepatic: less collagen, not as bright
portal: more collagen, brighter
Branching pattern of hepatic vs portal veins
Hepatic: longitudinally
Portal: transversely
Change in diameter of hepatic vs portal veins
Hepatic: increase in diameter closer to IVC
Portal: no change
Segmental location of hepatic vs portal veins
Hepatic: intersegmental (between)
Portal: intrasegmental (within)
Doppler of hepatic vs portal veins
Hepatic: pulsatile
Portal: continuous
Primary functions of the liver
- Bile production/excretion
- Excretion of hormones/drugs
- Metabolism of fats, proteins, carbs
- Enzyme activation
- Storage of glycogen, vitamins, minerals
- Synthesis of plasma proteins
- Blood detox and purification
- Kupffer cells: defense against invading organisms
What is the papillary process?
- anteromedial extension of the caudate lobe
- may appear separate from liver
- may mimic lymphadenopathy
What is Reidel’s lobe?
- the inferior aspect of the right lobe extends as far as the iliac crest
- tongue-like extension
- more common in females
What is the main difference between endocrine functions and exocrine functions?
Endo: direct release into bloodstream
Exo: need a pathway
What term is given to the condition of low white blood cells?
leukopenia
Where does the common bile duct terminate? Which two structures are located at the region of termination and determine if the bile passes through?
CBD terminates at the duodenum, sphincter of Oddi and Ampulla of Vater determine if bile passes through
The biliary system is made up of
liver, gallbladder, bile ducts
What are the functions of the biliary system?
- Drain waste products from liver into duodenum
- Aid in digestion with controlled release of bile
What does bile consist of?
Waste, cholesterol, bile salts
What are the two primary functions of bile?
- carry away waste
- break down fats
Where is the gallbladder located? What is its size and wall thickness?
- intraperitoneal, located within main lobar fissure
- 8-10 cm long, 3-5 cm wide
- wall: <3 mm
What are the parts of the gallbladder?
Neck, body, fundus
What are the wall layers of the gallbladder?
- mucosa
- muscularis
- serosa
What are the Rokitansky-Aschoff sinuses?
Pocket-like invasions of the mucosal epithelium into the muscularis layer that allow for bile accumulation without overextending and weakening the GB wall
What is the cystic duct?
A tortuous structure formed by GB neck tapering, it connects the neck of the GB with the CHD to form the CBD
What are the mucosal folds within the cystic duct called?
Spiral valves of Heister
What is bile produced by in the liver?
hepatocytes
What is cholecystokinin?
the hormone released by the duodenum in response to food, triggers GB to contract and release bile
Which artery supplies the GB?
cystic artery
What drains the GB?
a complicated venous plexus, it empties into the liver or portal vein
How is the CBD measured?
inner wall to inner wall distally (close to pancreatic head)
What is a phrygian cap?
the fundus folds over the body
What is a junctional fold?
a fold within the body of the GB
What is a Hartman’s pouch?
a fold between the neck and body of the GB, sacculation of the neck
What are the endocrine functions of the pancreas?
- secretion of hormones (insulin and glucagon)
- necessary for metabolism of carbs and glucose
What produces hormones in the pancreas?
Islets of Langerhans
What are the exocrine functions of the pancreas?
- production of digestive enzymes from acinar cells
What digestive enzymes do acinar cells produce?
Trypsin (protein), lipase (fats), amylase (starches)
Where is the pancreas located? What position is it in?
Retroperitoneal, usually oblique, may assume transverse or horseshoe position
What is the shape of the pancreas?
can be comma, tadpole, sausage, dumbbell
What is the size of the pancreas?
- about 12-15 cm long
- extends from duodenum to hilum of spleen
- AP diameter of head 2.5 to 3.5 cm
What plane do we look at pancreas in?
transverse because it allows you to view it in its elongated position
The head of the pancreas is _____ to the IVC
anterior
The gastroduodenal artery lies ______ to pancreas head, the CBD lies ______
anterolateral, posterolateral
What is the uncinate process of the pancreas?
the neck, connects head and body
The uncinate process is ______ to the IVC and _______ to the SMV
anterior, posterior
The body of the pancreas lies ______ and _______ to the head
superior and ventral
The pancreas body is _______ to the aorta, SMV, SMA, splenic vein
anterior
The pancreas body is located between which two vessels
splenic artery in front and splenic vein behind
The pancreas tail lies within the _____
splenic hilum
What is the Duct of Wirsung?
It is the main pancreatic duct, arises in the pancreas tail and travels through pancreas to open at the Ampulla of Vater
What is the Duct of Santorini?
It is the accessory duct and only functions when absolutely necessary for ex. blockage in Duct of Wirsung or distal CBD
What supplies the pancreas?
Branches of the splenic artery, hepatic artery, gastroduodenal artery and superior mesenteric artery
What drains the pancreas?
The portal splenic confluence:
The splenic vein travels through the pancreas posteriorly, meets with SMV and forms the portal vein
In adults, how does the pancreas appear in comparison to the liver?
slightly hyperechoic or isoechoic
In pediatrics, how does the pancreas appear in comparison to the liver?
slightly hypoechoic
How does the pancreas appear with increased age?
- decreased size
- increased echogenicity
How does the Duct of Wirsung appear on US?
seen in panc body as an echogenic line or anechoic, tubular structure
The Duct of Wirsung AP diameter should be
< 2 mm, if larger it indicates blockage
What is ectopic pancreatic tissue?
pancreatic tissue with no vascular or structural connection to true pancreas
What is partial duplication of the pancreas tail?
Rare, tail may appear enlarged, tail is split so there are two tails right next to each other
What kind of organ is the spleen?
Lymphatic, largest organ in lymphatic system
What part of the spleen is not covered by peritoneum?
a small portion near the hilum
Where is the spleen located?
posterior, left hypochondrium between the stomach fundus and the diaphragm
What is the size of the spleen?
L: 8-13 cm
H: 3-4 cm
W: 7 cm
150-200 g
What is the main function of the spleen?
It synthesizes blood proteins
- destroys RBC
- destroys microorganisms
How does the spleen contribute to fetal development?
- hematopoiesis
- erythropoiesis
How does the spleen aid in the body’s defense?
- production of lymphocytes
- production of plasma cells (WBC & antibodies)
What are lab indications for spleen US?
WBC count
- leukopenia
- leukocytosis
RBC count
- increased/decreased
Hematocrit
- increased/decreased blood oxygenation
Platelet count
- thrombocytosis
- thrombocytopenia
What supplies the spleen?
The splenic artery enters the hilum of the spleen and divides into 6 smaller arteries
What drains the spleen?
Splenic vein which is formed by smaller veins within the spleen that merge
When the splenic vein exits the hilum it joins with what?
The superior mesenteric vein, becoming the portal vein
What is the sonographic appearance of the spleen?
- moon shaped
- homogenous, smooth
- isoechoic or slightly hyperechoic to liver
- superior surface: convex, inferior: concave
What is it called when the spleen never developed?
aplasia
What is it called when the spleen is abnormally small?
hypoplasia
What is wandering spleen?
The spleen stops during development and doesn’t move up into left hypochondrium
What is accessory spleen? What else is this called?
- Pockets of ectopic splenic tissue that sit under the hilum and near the superior tip of the spleen
- also called splenules
What is the peritoneal cavity made up of?
- ligaments and folds that connect organs to each other and abdominal walls
- lesser and greater omentum
- mesenteries
- ligaments
- fluid spaces
What is peritoneum?
Smooth membrane that lines the entire abdominal cavity and the organs contained within the cavity
What does parietal peritoneum line?
The walls of the cavity
What does visceral peritoneum line?
The abdominal organs
What is the greater sac?
The general peritoneal cavity
What is the lesser sac?
Smaller area formed by spleen and posterior stomach
How do the greater and lesser sacs communicate?
Through the epiploic foramen, an opening inferior to the liver and duodenum
What is the lesser omentum?
Double layer of peritoneum extending from the liver to the lesser curvature of the stomach
The lesser omentum does what for the stomach?
Acts like a sling
What is the greater omentum?
Apron-like fold of peritoneum that hangs from the greater curvature of the stomach
How does the greater omentum lie?
Freely over intestines except for the superior portion which is fused with the transverse colon
The greater omentum can be compared to
A skirt for the intestines, covers small intestines
What does the lesser omentum attach?
The stomach to the liver
What is mesentery?
2 layered peritoneal folds which suspend the small bowel and colon to the posterior abdominal and pelvic wall
Mesentery is best visualized on ultrasounds when there is
the presence of ascites
Anterior abdominal wall layers (superficial to deep)
skin
fascia
muscle
fascia transversalis
peritoneum
What is Camper’s fascia?
Fatty superficial layer
What is Scarpa’s fascia?
Deep fibrous layer
Anterior abdominal wall muscles
- rectus abdominus
- external oblique
- internal oblique
- transverse abdominal
What are the rectus abdominus muscles? Location, size etc
- extend from xiphoid process to pubic bone
- midline
- encased in a sheath that attaches musculature to abdominal cavity
Sonographic evaluation of abdominal wall
Fatty composition layers: hypoechoic (depending on content)
Musculature: linear striations, hyperechoic (high density structures)
Aorta
Main vessel that carries blood from heart to rest of body
Abdominal aorta
Portion of descending aorta that supplies blood to abdomen, pelvis, and lower extremities
What are the layers of the aorta?
Tunica intima (inner)
Tunica media (mid)
Tunica adventitia (outer)
Where is the aorta positioned?
Posterior to:
- left lobe
- body of pancreas
- pylorus of stomach
- splenic vein
What are the main branches of the aorta?
celiac
SMA
renal arteries
IMA
Celiac axis
First branch off aorta
Sub-branches: left gastric artery, common hepatic artery, splenic artery
Supplies stomach, liver, spleen
What does the SMA supply?
Duodenum, small intestines, and transverse colon
Which renal artery branches off first?
Left renal artery branches off aorta first
What does the IMA supply?
large intestines
Where does the aorta bifurcate?
at L4
What does the aorta bifurcate into?
The right and left common iliac arteries which supply the respective legs
What does the aorta look like on US? Where is it?
blood filled lumen: anechoic
walls: echogenic
long, pulsatile, tubular structure
located anterior and left of the spine
- can use left lobe of liver as landmark
What is the normal proximal AP diameter of the aorta?
Men: 2.5-2.7 cm
Women: 2.1-2.3 cm
What is calcification of a vessel?
Accumulation of plaque products along the walls of the artery, resulting from disease, old age, poor dietary habits
What is aortic wall dissection?
Inner layer of aortic wall tears, caused inner and middle layer to separate
What is the IVC?
Main vessel that carries blood from the extremities and abdominal/pelvic cavity back to the heart
What is the IVC formed by?
Union of the common iliac veins
What does the IVC look like on US?
blood filled lumen: anechoic
walls: thin, collapsible, not as echogenic as aorta walls
phasic: diameter changes, color doppler evaluation
When do the kidneys ascend to their abdominal position?
12-15 weeks gestation
When does urine production begin?
When the kidneys ascend to their abdominal position
Where are the kidneys located?
Retroperitoneal, between L1 and L3, right slightly lower
How many nephrons are contained in the renal parenchyma?
Over 1 million
What does the cortex contain?
Convoluted tubules and glomerular capsules
What does the medulla contain?
renal pyramids containing collecting tubules and loops of Henle
What does the renal sinus contain?
Calyces, arteries, veins, lymphatics, peripelvis fat and fibrous tissue
What is the hilum of the kidney?
The concave medial border where vessels and lymphatics enter and exit
What are the 3 protective layers of the kidney?
- true capsule (inner)
- perirenal fat
- Gerota’s capsule (outer)
What is the size of a kidney?
L: 9-12 cm
W: 4-5 cm
AP diam: 2.5-3 cm
What is the formula for calculating a child’s renal length?
6.7 + (0.22 x age in years) = renal length in cm
What supplies the kidneys?
The renal artery that branches off aorta
How do the renal arteries divide?
- Divid into 4-5 segmental arteries at the hilum
- Segmental arteries divide into interlobar arteries
- Interlobar arteries travel into cortex and divide into arcuate arteries
- Arcuate arteries become interlobular arteries and supply arterioles
What drains the kidneys?
- Arterioles communicate with capillaries and transfer blood to venules
- venules travel via interlobular veins to arcuate veins to interlobar veins
- interlobar veins join to form main renal vein
- main renal vein drains into IVC
What enters and exits at the hilum?
- Renal vein exits anteriorly
- Ureter exits posteriorly
- Renal artery enters between them
What are the kidney functions?
- Excretion of metabolic waste
- Urine production
- Regulation of acid-base balance
- Regulation of serum electrolytes
- Production of erythropoietin
- Renin-angiotensin system (blood pressure, blood volume, etc)
What are indications for renal US?
- flank pain
- hematuria
- follow up
- classification of a mass
- post-surgical complications
- interventional guidance
- post-traumatic injury
What is the sonographic appearance of the cortex?
homogenous, hypoechoic to liver, hyperechoic to medulla
How does the sinus appear on US?
most echogenic due to fat content
How does the medulla appear on US?
anechoic
What is the only layer of covering seen on US?
True capsule, seen as thin echogenic line
How thick should the cortex be?
Greater than 1 cm
In males the bladder is located _______.
In females, ______
Males: superior to prostate
Females: inferior to uterus
What is the maximum capacity of the bladder?
500 ml
What is the typical capacity of the bladder?
300-350 ml
What is the detrusor muscle?
The bladder wall muscle that contracts to expel urine through the urethra
What does bladder wall thickening indicate?
inflammation, infection, or tumor
What is trabeculation of the bladder wall?
Hypertrophy of bladder wall muscle due to recurrent urethra obstruction
How thick should the bladder wall be if full? If empty?
Full: < 3 mm
Empty: < 5 mm
What is a normal post-void residual measurement?
Less than 50 ml