DIAGNOSTIC ULTRASONOGRAPHY

CHAPTER 23

PRINCIPLES OF ULTRASOUND

The use of sound waves beyond the audible frequency ( > 20,000 Hz) for diagnostic purposes.

Can be used for therapeutic purposes by using larger and continuous dosages – as in:

1) Generation of heat- treatment of low back pain, muscle strains, promote tissue regereration, kill malignant cells.

2) To pulverize kidney stones, gallstones.

PRINCIPLES OF ULTRASOUND

Sound waves are generated by the TRANSDUCER- the gizmo holding a piezoelectric crystal that changes electrical current into sound waves and vice versa.

Sound waves are generated, reflected off of tissues and “echo” back, and are picked up by the transducer (piezoelectric crystal) and converted to electrical activity.

PRINCIPLES OF ULTRASOUND

The image that is generated is dependent upon the time it takes the sound waves to return to the transducer.

The return time is a reflection of the distance the tissue is from the transducer and the degree to which the sound waves are reflected by that tissue (organ vs. bone vs. fat vs. fluid).

HAZARDS OF DIAGNOSTIC ULTRASOUND

In short, for diagnostic ultrasound, there are none.

Ultrasound for longer periods of time than are used in diagnostic ultrasound can generate sufficient heat as to be harmful.

And in higher frequencies (>100,000 Hz) can cause cavitation.

METHODS OF UULTRASOUND

1) PULSE-ECHO

2) DOPPLER

PULSE-ECHO METHOD

2 TYPES:

1) A MODE - amplitude modulation – echoes are displayed in graphic form, such as in an echocardiogram.

2) B MODE - brightness modulation – echoes are displayed as different intensities of brightness, giving a 2-dimensional cross-sectional image (“picture”, if you will). Can be static or dynamic (“real-time”).

DOPPLER METHOD

Sound waves bounced off of different objects have different frequencies.

With doppler ultrasound, these different frequencies are transformed into audible sounds, of different frequency.

The different frequencies can also be mapped to give a visual representation as well as an audible one.

DOPPLER METHOD

USES Flow through arteries and veins- to assess

patency of arterial grafts, obstruction to flow by thrombi, atherosclerosis, etc.- arterial flow can often be heard in cases where it can not be palpated.

Opening and closing of cardiac valves and flow through them- valvular stenosis, regurg.

DOPPLER METHOD

OBSTETRICAL USES Doppler stethoscope- to detect a fetal

heart beat episodically, or continuously as in labor.

Assessment of placental function / fetal growth – evaluates flow through the umbilical artery and vein, looks for differentials in flow

DOPPLER METHOD

COLOR FLOW IMAGING A type of doppler study. Asseses whether blood flow is laminar (the

usual way) or turbulent (the abnormal way). Useful in: cardiac valvular regurgitation;

identification of a false lumen in aortic dissection; congenital heart defects such as patent ductus arteriosus, atrial and venticular septal defects, which would appear as turbulent flow.

DOPPLER METHOD

DUPLEX SCANNING Uses both real-time imaging and doppler

flow together. Useful in evaluating a variety of vascular

problems: aneurysms, atheroscerotic plaques.

APPLICATIONS OF ULTRASOUND

CEREBRAL CIRCULATION CAROTID ARTERY GYNECOLOGIC / OBSTETRIC TRANSVAGINAL / TRANSABDOMINAL TRANSRECTAL / TRANSTHORACIC /

TRANSESOPHAGEAL STRESS ECHOCARDIOGRAM ECHOENCEPHALOGRAM BREAST BLADDER

CEREBRAL CIRCULATION

Measures blood flow in the cerebral circulation, particularly in the:

1) Middle, anterior, and posterior cerebral arteries.

2) Distal internal carotid.3) Basilar artery. Often combined with doppler duplex

ultrasound and arteriography.

CAROTID ARTERY SCANS

Atherosclerosis is associated with thickening of the intima of the artery.

Risk of cardiovascular disease and stroke is proportional to the thickness of the intima, which is a reflection of the degree of atherosclerosis.

Useful for screening both symptomatic patients who may need surgical intervention and asymptomatic patients who may need prevntive measures.

GYNECOLOGIC ULTRASOUND

Uterus- size, shape (bicornuate), presence of masses within (fibroids, neoplasms).

Ovary- presence of masses, cysts, neoplasms.

Tubes- hydrosalpinx, pyosalpinx in PID, ectopic pregnancy.

BENIGN CYSTIC TERATOMA

RIGHTOVARY

OBSTETRICAL ULTRASOUND

Confirmation of intrauterine pregnancy, presence of ectopic pregnancy, # of fetuses.

Position of fetus(es), placenta (previa). Guidance for amniocentesis. Evaluation of fetal growth, gestational age. Evaluation of amniotic fluid volume. Structural / congenital abnormalities of the

fetus.

ECTOPIC PREGNANCY

UTERUS:

SOLID MASS WITHINNO GESTATIONAL SAC

ECTOPIC PREGNANCY

ADNEXA:

CYSTIC MASS,BETA HCG 17,000

COLOR DOPPLER (FLOW)STUDY

INCREASEDFLOW

ECTOPIC PREGNANCY

TWIN GESTATION

OB (FETAL) ULTRASOUND

26 WEEK FETUS:

CONGENITAL POLYCYSTIC

KIDNEYS

23 YOF AT 20 WEEKS GESTATION

FETAL HYDROTHORAX (BILATERAL PLEURAL EFFUSIONS) AND ASCITES, C/W HYDROPS FETALIS

23 YOF AT 20 WEEKS GESTATION

FETAL HYDROTHORAX (BILATERAL PLEURAL EFFUSIONS) AND ASCITES, C/W HYDROPS FETALIS

OLIGOHYDRAMNIOS

OB SCAN - OMPHALOCOEL

OB SCAN - OMPHALOCOEL

PLAIN FILM - OMPHALOCOEL

TRANSVAGINAL ULTRASOUND

Transducer placed in the vagina. USEFUL FOR: Evaluation of follicular development,

ovulation. Ruling out ectopic pregnancy. Evaluation of endometrial thickness – in

the assessment of post-menopausal bleeding, need for biopsy.

Incompetent cervix.

BICORNUATE UTERUS

SAME BICORNUATE UTERUS

GESTATIONAL SAC

SAME BICORNUATE UTERUS

OTHER HORN FLUID-FILLED

ONLY

TRANSVAGINAL SCAN

UTERUS:

COMPLEX, CYSTICMASS WITHIN THE

UTERUS

DDxCYSTIC POLYP,

ENDOMETRIAL Ca,ENDOMETRIALHYPERPLASIA

TRANSVAGINAL SCAN

On this image performed during sonohysterography, two masses, one polypoid and another more broad-based,

extending from the endometrial lining are evident.

ULTRASOUND LEFT OVARY

HEMORRHAGIC CYST

SAME PATIENT

HEMORRHAGIC CYST RESOLVED

ABDOMINAL ULTRASOUND

Often the 1st test used to evaluate abdominal pathology (or 2nd, behind a KUB).

Or complementary to other studies such as radionuclide studies, CT, MRI, X-Ray/Contrast studies, etc. No radiation, cheaper.

Needle-guided biopsies, paracentesis. Examples: appendicitis, cholelithiasis, aortic

aneurysms, cysts / masses / tumors / abscesses / ascites.

CHOLECYSTITIS

GALLBLADDER:

GALLSTONE,WALL THICKENING

SAME PATIENTCOMMON BILE DUCT ENLARGED

ABDOMINAL SONOGRAM

A thickened gall bladder wall is noted, with some pericholecystic fluid and shadowing echogenic foci likely representing stones

APPENDICITIS

TRANSRECTAL ULTRASOUND

Primarily for evaluation of the prostate- size, shape, etc., to evaluate for BPH, prostate cancer.

Used after evaluation by DRE (digital rectal exam) and PSA (prostate-specific antigen).

Used in needle-guided biopsies, implantation of radioactive seeds for treatment of malignancy of the prostate.

TRANSTHORACIC ECHOCARDIOGAPHY

USEFUL IN THE EVALUATION OF Valvular defects, chamber size. Structural abnormalities- patent ductus, atrial

and ventricular septal defects. Pleural effusion, cardiac tamponade. Color imaging can detect flow – laminar vs.

turbulent. Some changes in coronary flow. ECG sometimes done simultaneously.

TRANSESOPHAGEAL ULTRASOUND

Generates an image unimpeded by the lungs and chest-wall structures.

Especially good visualization of the left atrium and aortic root.

Examples: infective endocarditis, aortic dissection, cardiac origin of an arterial embolus such as atrial fib. much better than TTE.

RISKS: bleeding, aspiration, perforation, arrhythmias.

ECHOENCEPHALOGRAM

Ultrasound can not penetrate bone. Limited use in the adult. This modality is most useful for imaging

the newborn as the skull (sutures) have not completely fused.

Useful for evaluating: mostly, things that shift the midline, hydrocephalus, size of the cerebral ventricles, intracranial hemorrhage in the newborn.

ECHOENCEPHALOGRAM

“ANEURYSM” OF THE VEIN OF GALEN,WHICH IS REALLY AN A-V FISTULA

SAME PATIENT - ANGIOGRAM

1 DAY OLD INFANT W/ HEART FAILURE

1 DAY OLD INFANT W/ HEART FAILURE

Head ultrasound shows a cystic mass, posterior to the third ventricle. The mass is continuous with the dilated straight sinus.

1 DAY OLD INFANT W/ HEART FAILURE

Doppler examination shows pulsatile high flow in the cystic mass.

THORACIC SONOGRAMS

Limited utility due to the lack of penetration of ultrasound by air.

Can detect pleural fluid, abscess, malposition of the diaphragm.

ULTRASOUND OF THE BREAST

Usually done adjunctively with or as a follow-up to mammography.

Differentiates between solid and cystic lesions. Helpful in women w/ dense breasts as glandular

tissue and malignancy both show up white on mammogram. On ultrasound, malignancy appears black.

Used to guide needle biopsy and to place a surgical clip to mark the area for future treatment.

MAMMOGRAM

PALPABLE MASS

BREAST ULTRASOUND

PALPABLE MASS,CYSTIC ON

ULTRASOUND

BONE SONOGRAMS

Primary use is as a screening tool for osteoporosis, looking at the heel, as healthy bone echoes sound waves faster than does osteoporotic bone.

Also used for congenital hip dysplasia (dislocation).

BLADDER ULTRASOUND

Used to determine volume of urine. Main purpose is to determine urine

volume without having to catheterize the bladder, avoiding the risk of infection.

Image of the bladder is matched to an image on the screen corresponding to a pre-calculated volume.

Compression U/S - LLE: Noncompressibility of common femoral vein with echogenic thrombus within the vein lumen consistent with chronic DVT.

POLYCYSTIC KIDNEY DISEASE

18 YOM W/ TESTICULAR MASS

18 YOM W/ TESTICULAR MASS

EPIDERMOID CYST OF THE TESTICLE

ULTRASOUND-GUIDED NEEDLE BIOPSY OF THE LIVER