Information ⬇
Editors
Ultrasonographic Examinations
Abdominal ultrasonography
Patient preparation
- Fasting for 4 hours is necessary when examining the gallbladder because eating causes a contraction of the bladder. In other indications, the effect of eating or drinking is minimal or null.
- In emergency cases, the examination can be performed without preparations.
Upper abdomen
- Includes the liver, gallbladder, biliary tract, pancreas, spleen, kidneys, aorta and retroperitoneal space (for details see below).
Ascites
- Clinically suspected ascites can be confirmed.
- Ascites formation may be due to heart failure, cirrhosis of the liver, nephrotic syndrome or a tumour.
- Scant ascites is most easily detected between the right kidney and liver where it forms a crescent-shaped fluid collection. A similar view can be found between the left kidney and the spleen. Look for ascites also in the lower abdomen around the urinary bladder where small amounts of fluid often accumulate.
- In women of reproductive age, a small amount of free fluid in the recto-uterine pouch (fossa Douglasi) between the uterus and rectum is normal.
Abdominal infections
- Ultrasonography may be helpful in detecting possible acute internal infection in the abdominal cavity or peritonitis (free fluid). Peritonitis is difficult to detect because decreased intestinal motility may make the visibility extremely bad.
- In patients with peritonitis, ultrasonography is rarely a sufficient imaging method, unless the disease is caused by cholecystitis. In other cases a CT scan is usually required.
- Fluid in the abdominal cavity is an unspecific finding.
- When intra-abdominal abscess as a complication of abdominal surgery or appendicitis Computed Tomography for Diagnosis of Acute Appendicitis in Adults is suspected.
- However, a CT scan is often required.
- When suspecting acute appendicitis in children, young adults and pregnant women http://www.dynamed.com/condition/appendicitis-in-adolescents-and-adults#ULTRASOUND, ultrasonography is the primary imaging examination Computed Tomography for Diagnosis of Acute Appendicitis in Adults.
- When a biliary aetiology is suspected for an acute abdomen or when the patient's symptoms are relatively mild, the examination strategy is probably best started with ultrasonography, followed by CT scan for patients with a negative or indefinite result in ultrasonography. A CT scan should be performed especially in elderly patients and in patients with severe symptoms.
- The abdomen may be pressed lightly with the ultrasound probe, whereby the more precise location of the painful are may be detected (so-called sonopalpation). This is useful e.g. in detecting cholecystitis.
Pancreas
- Included in the upper abdominal examination
- Indications
- Pancreatic ultrasonography is rather insensitive in pancreatic diagnostics. Lying a longer time in supine position may cause the intestinal gas to accumulate and shadow the retroperitoneum in an unfavourable manner. It is recommendable to try also other positions (tilting in different directions, sitting) to help in examining the pancreas that may sometimes be difficult to discern.
- Ultrasonography of the pancreas should not be performed by a clinician (non-radiologist) if the aim is to rule out a disease.
Liver
- Included in the upper abdominal examination
- All liver diseases: hepatomegaly, cirrhosis, tumours and metastases, cysts and abscesses, biliary obstruction, abdominal trauma, jaundice.
- Cirrhosis and fatty change of the liver increase the echo intensity of the liver. The adjacent renal cortex provides a good reference point because it normally has similar density to the liver and consequently their brightness in the image is equal.
- The sensitivity in the diagnostics of cirrhosis is probably poor. The liver may be smaller than usual, with poorly defined borders and uneven echogenicity. Ascites and collateral vessels may be detected in the terminal phase.
Kidneys and adrenal glands
Urinary bladder and prostate
Pelvic ultrasonography and ultrasonography during pregnancy
Ultrasonography of blood vessels
Aorta
- Aortic aneurysm Aortic Aneurysm and Dissection. An aneurysm larger than 3 cm in size warrants follow-up and a size over 5 cm requires consideration of operative treatment.
Vascular prostheses
- Detection of surgical complications (haematoma, aneurysm)
Veins
- Investigation of occlusion in the deep veins Deep Vein Thrombosis and diagnosis of occlusion in the femoral and popliteal veins (video Compression Ultrasonography of Veins)
- Detection of superficial thrombophlebitis (video Superficial Thrombophlebitis (Ultrasonography)) if clinical diagnosis is not clear or in order to assess whether thrombosis reaches up to the groin, or to assess the extent of the thrombosis for treatment decisions.
- The function of superficial veins can be assessed when planning surgery for varicose veins Venous Insufficiency of the Lower Limbs. Doppler pen is usually adequate for the examination (video Superficial Venous Insufficiency (Pen Doppler Examination)).
- Examination of the diameter of the inferior vena cava and its respiratory variation.
- Diameter < 1.5 cm and > 50% variation suggests hypovolaemia. Diameter > 2.5 cm and mild or absent respiratory variation suggests excess fluid load or increased pressure of the right atrium due to some other cause (e.g. pulmonary embolism).
Thoracic ultrasonography
Pleural and pericardial cavity
Thyroid and parathyroid ultrasonography
Soft tissues and joints of the extremities
Maxillary and frontal sinuses
Ultrasonographically guided biopsies and punctures
- Pleural fluid (video Thoracentesis) and ascites (video Removal of Ascites) may be located before puncture.
- Detection and locating synovial fluid before joint puncture facilitates diagnostic aspiration especially from elbow, ankle and wrist joints. If the patient is afraid of the puncture, locating the fluid with ultrasonography usually ensures that the procedure is successful at first attempt.
- Evacuation of cysts, haematomas and abscesses
- Cytological and histological specimens of suspected tumours (e.g. breast, thyroid gland) can be collected under ultrasonographic guidance.
Ultrasonographic examinations by general practitioners
- Notice that the information presented in this chapter is based on the situation and experiences in Finland. National and local differences may apply, including the authorization and legal reguirements for performing various examinations. Find out about local policies and requirements.
- Some ultrasonographic examinations are suitable to be performed by any doctor, and some by a general practitioner with a special training or by a specialist other than a radiologist.
- Ultrasonography is a dynamic examination that must be interpreted during the examination. The interpretation cannot usually be reliably performed from printouts afterwards.
- A doctor performing ultrasonographic examinations should be trained by a specialist.
- When performing an ultrasonography, the findings should be assessed in relation to the physician's own expertise and the acquired visibility. No interpretations should be made of an unclear finding or when the visibility is inadequate. Instead, the patient should be referred, as necessary, for further examinations to, for example, a radiologist.
- Any doctor can perform the following examinations after local training
- Determination of the size and position of a fluid cavity before puncture (urinary bladder, pleural space, ascites, abscess, synovial fluid)
- Determination of residual urine volume and size of the prostate Determining the Volume of Residual Urine by Ultrasonography, approximately, when planning pharmacotherapy for prostatic hyperplasia
- A doctor with special training in ultrasonography can perform the following examinations
- Search for gallstones and signs of acute cholecystitis (thickened gallbladder wall, positive sonopalpation) in a patient with upper abdominal pain
- Rule out hydronephrosis
- Diagnosis or exclusion of abdominal aortic aneurysm
- Detection or exclusion of pericardial effusion
- Detection or exclusion of pneumothorax
- Detection of ascites or intra-abdominal bleeding (e.g. in a patient with mild, blunt abdominal trauma that does not require referral on the basis of the history or clinical presentation)
- Rough estimation of the size of the spleen (a length exceeding 12-14 cm is abnormal)
- Detection of a hydrocele and spermatocele
- Differentiation between a fluid cavity and other subcutaneous masses (e.g. as a preliminary examination before a puncture): abscess, seroma in a surgical wound, Baker's cyst, ganglion, cyst of the breast
- Diagnosis or exclusion of venous thrombosis in vena poplitea, vena femoralis or a superficial vein (an obstructed vein cannot be compressed by pressing)
- Some ultrasonographic examinations during pregnancy Ultrasound Scanning during Pregnancy.
Evidence Summaries ⬆