intro to us_hitachi and dr peter

INTRODUCTION TO SMALL ANIMAL INTRODUCTION TO SMALL ANIMAL UltrasoundUltrasound

Jeff King, DVM and Edgar Elguezabal

COURSE OUTLINECOURSE OUTLINE

Ultrasound PhysicsUltrasound Physics How Does it Work?How Does it Work?

Frequency & TransducersFrequency & Transducers Imaging ModalitiesImaging Modalities Imaging ArtifactsImaging Artifacts

Getting Ready To ScanGetting Ready To Scan ““ButtonologyButtonology””

Patient Preparation & PositioningPatient Preparation & Positioning The Complete Abdominal ScanThe Complete Abdominal Scan

Applications Of Ultrasound In Private Applications Of Ultrasound In Private PracticePractice

Ultrasound PHYSICS - IUltrasound PHYSICS - I Soundwaves emitted from the transducer are reflected Soundwaves emitted from the transducer are reflected

back at different amounts depending on the type of back at different amounts depending on the type of tissue.tissue.

The computer in the machine processes these The computer in the machine processes these reflections into an image.reflections into an image.

Usefulness of USUsefulness of US

Ultrasound Physics - IIUltrasound Physics - II Fluid reflects few sound waves, and will Fluid reflects few sound waves, and will

appear black.appear black. Tissues reflect a variable amount of sound Tissues reflect a variable amount of sound

waves and will appear in shades of gray.waves and will appear in shades of gray. Bone and Tissue Interfaces reflect large Bone and Tissue Interfaces reflect large

amounts of sound waves and will appear amounts of sound waves and will appear white.white.

Descriptive Terms – anechoic – black; Descriptive Terms – anechoic – black; hypoechoic – darker; isoechoic – equal; hypoechoic – darker; isoechoic – equal; hyperechoic - brighterhyperechoic - brighter

Transducer FrequenciesTransducer Frequencies 1-18 megahertz (million cycles per second).1-18 megahertz (million cycles per second). Low Frequency – 1-5 MHzLow Frequency – 1-5 MHz• More depth of penetration into the bodyMore depth of penetration into the body• Use for medium to large sized patients orUse for medium to large sized patients or

Deeper structuresDeeper structures• Provides moderate resolution (detail)Provides moderate resolution (detail)

High Frequency – 7.5-18 MHzHigh Frequency – 7.5-18 MHz• Less depth of penetration into the body.Less depth of penetration into the body.• Use for medium to small pets orUse for medium to small pets or

superficial structures.superficial structures.• Provides high resolution (detail)Provides high resolution (detail)

Transducer SelectionTransducer Selection

With experience transducer frequency With experience transducer frequency selection becomes more intuitive.selection becomes more intuitive.Body condition will influence resolution Body condition will influence resolution significantly.significantly.Thin and well hydrated image the bestThin and well hydrated image the bestObese and dehydrated will image poorly.Obese and dehydrated will image poorly.

Choose the transducer frequency to Choose the transducer frequency to maximize image quality…maximize image quality…

TRANSDUCERS/PROBESTRANSDUCERS/PROBES Digital Ultrasound machines utilize Digital Ultrasound machines utilize

Piezoelectric Crystals that convert electrical Piezoelectric Crystals that convert electrical to sound energy.to sound energy.

The returns are processed by the computer The returns are processed by the computer in the machine to create the image displayed in the machine to create the image displayed on the screen.on the screen.

Most transducers are capable of imaging at a Most transducers are capable of imaging at a variety of frequencies.variety of frequencies.

Convex TransducerConvex Transducer Micro-convex transducer– Micro-convex transducer–

Curved footprint that yields Curved footprint that yields a triangular image.a triangular image.

• Preset @ 5, 6.5, 8,10 MHzPreset @ 5, 6.5, 8,10 MHz• Best for abdominal survey Best for abdominal survey

and cardiac/thoracic and cardiac/thoracic studies. studies.

Linear TransducerLinear Transducer

• Linear/Trapezoid Linear/Trapezoid Transducer – straight Transducer – straight footprint that yields a footprint that yields a rectangular image.rectangular image.

• Preset to image @ 5, Preset to image @ 5, 7.5, 10 ,13, 18MHz 7.5, 10 ,13, 18MHz

• Best for imaging Best for imaging abdominal details or abdominal details or small parts.small parts.

Ultrasound PHYSICSUltrasound PHYSICSImaging ModalitiesImaging Modalities

B-Mode (Brightness)B-Mode (Brightness)• Yields a 2-D image.Yields a 2-D image.• Utilized for imaging tissue Utilized for imaging tissue

or organ structure, size or organ structure, size and contour.and contour.

M-Mode (Motion)M-Mode (Motion)• Yields a swept 2-D Yields a swept 2-D

image.image.• Utilized for precise Utilized for precise

measurements of cardiac measurements of cardiac walls and chambers.walls and chambers.

Ultrasound PHYSICSUltrasound PHYSICSTechnique-dependent ArtifactsTechnique-dependent Artifacts

• Noise caused by excess gain.Noise caused by excess gain.• Solution: turn down the overall gainSolution: turn down the overall gain

Descriptive TerminologyDescriptive Terminology

Appearance of TissuesAppearance of Tissues

Ultrasound PHYSICSUltrasound PHYSICSTTechnique-dependent Artifactsechnique-dependent Artifacts

• Low gain artifactLow gain artifact• Solutions: select another frequency, increase Solutions: select another frequency, increase

the far gain, apply more alcohol/acoustic gel.the far gain, apply more alcohol/acoustic gel.

EnhancementEnhancement

ShadowingShadowing

Liver and DiaphragmLiver and Diaphragm

Kidney and SpleenKidney and Spleen

Pregnancy = Puppies!Pregnancy = Puppies!

Ultrasound PHYSICSUltrasound PHYSICSTechnique-Dependent ArtifactsTechnique-Dependent Artifacts

• Electrical interference can occur from other equipment in Electrical interference can occur from other equipment in the facility. Causes a variety of the facility. Causes a variety of ““60 cycle noise60 cycle noise”” on the on the image screen.image screen.

• Solutions: move power cord to a different outlet, turn off Solutions: move power cord to a different outlet, turn off the interfering equipment (dental scaler, clippers, etc.).the interfering equipment (dental scaler, clippers, etc.).

Ultrasound PHYSICSUltrasound PHYSICSInherent Sonographic ArtifactsInherent Sonographic Artifacts

• Shadowing: caused by soundwaves hitting a Shadowing: caused by soundwaves hitting a highly reflective object, ex. uroliths, choleliths.highly reflective object, ex. uroliths, choleliths.

• Very helpful in detecting mineral densities.Very helpful in detecting mineral densities.• Solution: recognize, scan from a different angle.Solution: recognize, scan from a different angle.

Ultrasound PHYSICSUltrasound PHYSICSInherent Sonographic ArtifactsInherent Sonographic Artifacts

• Edge-shadowing: caused by refraction of soundwaves at Edge-shadowing: caused by refraction of soundwaves at fluid- tissue interface at the edges of round structures, fluid- tissue interface at the edges of round structures, ex. Urinary bladder, renal medulla and diverticula.ex. Urinary bladder, renal medulla and diverticula.

• Very helpful in detecting fluid structures.Very helpful in detecting fluid structures.• Solution – recognize.Solution – recognize.

Ultrasound PHYSICSUltrasound PHYSICSInherent Sonographic ArtifactsInherent Sonographic Artifacts

• Reverberation: caused by soundwaves interfacing with two tissues Reverberation: caused by soundwaves interfacing with two tissues having markedly different acoustic properties, ex. bowel gas, poor skin having markedly different acoustic properties, ex. bowel gas, poor skin contact, metallic objects.contact, metallic objects.

• Solutions: shave better, apply more alcohol/gel, change angle of Solutions: shave better, apply more alcohol/gel, change angle of transducer, rotate patient. transducer, rotate patient.

• Classic: Comet Tail: Classic: Comet Tail:

Ultrasound PHYSICSUltrasound PHYSICSInherent Sonographic ArtifactsInherent Sonographic Artifacts

• Enhancement: caused by soundwaves travelling Enhancement: caused by soundwaves travelling through fluid-filled structures, ex. urinary or gall through fluid-filled structures, ex. urinary or gall bladder, cyst, seroma/hematoma. bladder, cyst, seroma/hematoma.

• Very helpful in detecting fluid structures.Very helpful in detecting fluid structures.• Solutions: recognize, reduce overall or far gain.Solutions: recognize, reduce overall or far gain.

Ultrasound PHYSICSUltrasound PHYSICSInherent Sonographic ArtifactsInherent Sonographic Artifacts

• Mirror-image: Caused by curved, strongly Mirror-image: Caused by curved, strongly reflective interfaces, ex. diaphragm-lung.reflective interfaces, ex. diaphragm-lung.

• Solutions: possibly change angle of probe, Solutions: possibly change angle of probe, rotate patientrotate patient

Ultrasound PHYSICSUltrasound PHYSICSInherent Sonographic ArtifactsInherent Sonographic Artifacts

• Side-lobe: caused by minor beams of Side-lobe: caused by minor beams of soundwaves travelling out at different angles soundwaves travelling out at different angles from the primary beam. Occurs with curved from the primary beam. Occurs with curved surfaces, fluid and air.surfaces, fluid and air.

• Solution: reduce overall gain, adjust down TGCSolution: reduce overall gain, adjust down TGC

GETTING READY TO SCANGETTING READY TO SCAN Give yourself enough time to scan without Give yourself enough time to scan without

disturbances. disturbances. Pick an assistant who is capable of Pick an assistant who is capable of

restraining a patient without asking too restraining a patient without asking too many questions.many questions.

Scan in a darkened room on a table where Scan in a darkened room on a table where the assistant is across from you.the assistant is across from you.

For abdominal studies a 8-12 hour fasted For abdominal studies a 8-12 hour fasted patient is ideal.patient is ideal.

GETTING READY TO SCANGETTING READY TO SCAN

Shave the ventral abdomen like you would Shave the ventral abdomen like you would do for an exploratory surgery.do for an exploratory surgery.

Apply sprayed alcohol to the skin to Apply sprayed alcohol to the skin to displace air.displace air.

Apply Ultrasound gel to the transducer.Apply Ultrasound gel to the transducer. Maximize patient comfort with v-troughs, Maximize patient comfort with v-troughs,

towels, foam padding, calm environment, towels, foam padding, calm environment, compassion.compassion.

GETTING READY TO SCANGETTING READY TO SCAN Imaging can be performed in dorsal, left or right Imaging can be performed in dorsal, left or right

lateral recumbency.lateral recumbency. Stressed or struggling patients need to be Stressed or struggling patients need to be

sedated when safe. sedated when safe. Panting can lead to aerophagia which can Panting can lead to aerophagia which can

increase GIT gas.increase GIT gas. Resist the temptation to focus on the obvious Resist the temptation to focus on the obvious

lesion. lesion. Be systematic and complete in your approach to Be systematic and complete in your approach to

a abdominal studya abdominal study..

SYSTEMATIC APPROACHSYSTEMATIC APPROACH

Mid-caudal

Left-caudal

Left-cranial

Mid-cranial

Right-cranial

Right-caudal

Bladder, urethra, aorta, iliac lymph Bladder, urethra, aorta, iliac lymph node, prostate, testes.node, prostate, testes.

L kidney, l adrenal, tail of spleen, L kidney, l adrenal, tail of spleen, L ovary/uterine horn. L ovary/uterine horn.

L side of the liver, left limb L side of the liver, left limb pancreas, stomach, head of pancreas, stomach, head of spleen.spleen.

Liver, gall bladder, biliary tract, Liver, gall bladder, biliary tract, hepatic hilus, portal vein, cranial hepatic hilus, portal vein, cranial VC, pylorus.VC, pylorus.

Right side of the liver, right kidney, Right side of the liver, right kidney, r adrenal, main body of pancreas.r adrenal, main body of pancreas.

Duodenum, ileum, jj, R Duodenum, ileum, jj, R ovary/uterine horn, colon, ovary/uterine horn, colon, mesenteric root, ileocecalcolic mesenteric root, ileocecalcolic junction. junction.

APPLICATONS OF Ultrasound IN APPLICATONS OF Ultrasound IN PRIVATE PRACTICEPRIVATE PRACTICE

Ultrasound HAS GREAT VALUE IN INTERNAL MEDICINE WORKUPS WHEN MINIMUM Ultrasound HAS GREAT VALUE IN INTERNAL MEDICINE WORKUPS WHEN MINIMUM DATABASE DATA DO NOT GIVE A DEFINITIVE DIAGNOSIS.DATABASE DATA DO NOT GIVE A DEFINITIVE DIAGNOSIS.

EMERGENCY FAST ABDOMEN: blunt or penetrating trauma, bloat, spleen torsion, foreign EMERGENCY FAST ABDOMEN: blunt or penetrating trauma, bloat, spleen torsion, foreign bodies, pyometra; to quantify and locate fluid pockets and to obtain a fluid sample; quick bodies, pyometra; to quantify and locate fluid pockets and to obtain a fluid sample; quick assessment of the liver, spleen, kidneys, bladder, GI tract.assessment of the liver, spleen, kidneys, bladder, GI tract.

EMERGENCY FAST THORAX; blunt or penetrating trauma, effusions and fluid sampling, EMERGENCY FAST THORAX; blunt or penetrating trauma, effusions and fluid sampling, masses, pneumothorax, heart disease.masses, pneumothorax, heart disease.

GENERAL INTERNAL MEDICINE PRACTICE: GI foreign body vs inflammation vs pancreatitis; GENERAL INTERNAL MEDICINE PRACTICE: GI foreign body vs inflammation vs pancreatitis; ascites assessment and sampling; location of masses; bladder uroliths, , prostatic disease, ascites assessment and sampling; location of masses; bladder uroliths, , prostatic disease, cystitis, neoplasia; differentiation of diffuse liver diseases via biopsy; kidney, ureters; pyometra; cystitis, neoplasia; differentiation of diffuse liver diseases via biopsy; kidney, ureters; pyometra; cystocentesis; GI wall thickening; lymphadenopathy; adrenal measurements; hernias; ocular and cystocentesis; GI wall thickening; lymphadenopathy; adrenal measurements; hernias; ocular and retrobulbar diseases; characterize types of heart disease.retrobulbar diseases; characterize types of heart disease.

SINGLE ORGAN STUDIES:SINGLE ORGAN STUDIES: Skin/muscle masses/abscesses/cysts – characterize, margins, guided FNA, drainageSkin/muscle masses/abscesses/cysts – characterize, margins, guided FNA, drainage Thyroid/parathyroidThyroid/parathyroid TestesTestes Bicipital tendon, cruciate, joint effusionsBicipital tendon, cruciate, joint effusions Early pregnancy detection (day 21 in dogs) and fetus countEarly pregnancy detection (day 21 in dogs) and fetus count Discounted Wellness ExamsDiscounted Wellness Exams