AID TO ABDOMINAL ULTRASOUND

DR S.PRAKASH MD.
FOUNDER FELLOW INDIAN COLLEGE OF MEDICAL ULTRASOUND.
SENIOR CONSULTANT
TB SAPRU HOSPITAL.ALLAHABAD
UP INDIA.

INTRODUCTION

My motive of writing of this book is to give a ready hand book for sonographers and graduate students in sonology for immediate consultation at the time of doing abdominal sonography.It is not replacement of various voluminous text books of ultrasonography.
Abdominal ultrasound is used to evaluate soft tissue organs in abdomen.eg
LIVER
GALLBLADDER
SPLEEN
KIDNEY
PANCREAS
ABDOMINAL AORTA & OTHER VESSELS OF ABDOMEN
INFLAMED APPENDIX.
PREPARATION
1 For GB,LIVER,PANCREAS and AORTA fat free meal and 8 to 12 hrs fasting before test
2 For KIDNEY,URINARY BLADDER, URETER and PROSTRATE Fasting of 8 to 12 hrs done on evening before test to avoid gases.On the.day of test 1 hr before, 6 glass of water is to be taken to fill the bladder.

Abdominal ultrasound is done to solve various clinical problems as pain in abdomen,burning during micturation,hematuria, jaundice and stones in gallbladder and kidney.Beside this assessment of damages to various organs caused by diseases,blunt injury abdomen and guide lines procedure as needle biopsy and aspiration.also could be done.
Of course there is certain limitations of USG also as we can not evaluate stomach,intestine,colon and rectum as these organs are filled with gases and air which reflects the ultrasound waves. In obese persons tissues weakens the ultrasound waves creating problems when doing ultrasound,occasionly intestinal gases prevents visualization of Pancreas and Aorta.
BENEFITS.
1 Ultrasound is cheap and painless.
2 It is noninvasive.
3 No ionizing radiation.
4 Real time imaging and clear soft tissue pictures as compared to X-Ray.
5 No risk involved.

MEASUREMENTS

LIVER. .Liver is measured from mid spine to outer surface of liver in transverse scan.On longitudinal scan It can be measured in mid hepatic line from superior to inferior margins.Which should not exceed 13cm normaly,if it is more than 15.5cm, liver is said to be enlarged Between 13 cm and 15.5cm it is equivocal.
Some sinologist measures at mid clavicular line which should be less than 10.5cm +-1.5cm in longitudinal diameter and 8.1cm +-1.9 cm anteroposteriorly.if it is more than 15.5 cm hepatomegaly present.

SPLEEN. .Average adult spleen is 12 cm in length, 7 cm in breadth and 3-4cm in thickness.if it is more than 14 cm ,it is enlarged.When ever spleen is found extending below the lower pole of left kidney even then spleen could be taken enlarged..

PANCREAS. .Normal Transverse measurement is as follows
Head 2.08 cm+- 0.4cm
Body 1.16 cm+-0.29 cm
Neck 0.95 cm+-0.26 cm
Tail0.7 cm+-2.8 cm
However pancreas should not exceed following diameter anteroposteriorly
Head,Body.Tail each 3.5 cm
Neck 2.5cm
Pancreatic duct< 3mm.
Texture of Pancreas in comparison to liver is isosonic or hyperechoic.

RENALS. Normal size of kidney is 8 to 13 cm* 5cm.
Renal sinus contains major branches of renal artery ,veins and calyces,lying centrally
And is highly echogenic.
Renal cortex is normally 2.5 cm thick.

ADRENAl.GLAND. Normal size is 4 cm*2.5 cm*0.5 cm

PROSTRATE .Normal size in adult is
4 cm transversely * 2 cm Anteroposteriorly* 3 cm craniocaudaly.
Weight is 20 gms,weight can be calculated 4/3 r .( r is average of Anteroposterior+Transverse diameter.

LIVER
HEPATOMEGALY.
A. LARGE TENDER HEPATOMEGALY.
1.Congestive cardiac failure.
2.Amoebic Abscess./Hepatitis.
3.Infective Hepatitis.
4.Secondaries in Liver.
5.Infected Cyst.
B. NON TENDER HEPATOMEGALY.
1.Cirrhosis of Liver
2.Fatty Infilteration/Amyoloidosis.
3.Hepatoma
4.Lymphomas( Hodgekins.non Hodgekins lymphoma)
5.kalazar
6. Malaria
7. Hydatid cyst
8. Myelofibrosis.
C.Other causes are.
1.Tuberculosis
2.Typhoid
3 Lymphosarcoma.
4 Biliary cirrhosis
5Multiple myeloma
6.Lipoid Storage diseases( Gauchers disease)
7.Polycystic Disease.
8.Diabetes Mellitus
9.Toxic Hepatitis(Anaesthetic Drugs,Gold ,Dilantin)
10.Fungal Disease( Actinomycosis,Histoplasmosis)
11. Infectious mononucleosis.

BRIGHT LIVER.
Characteristic features are.
1.Strong echoes from liver parenchyma which is equal to peri portal structures
2.Liver appears flat,ground glass texture as normal peri vascular markings are
lost, all vessels appears as wall less cleft.
3.when compared with renals,renal parenchyma appears almost echo free
while liver is highly echogenic.
4.Echogenicity of liver parenchyma and ligamentum teres is same.

Causes are.
1.Micronodular cirrhosis of liver
2.Fatty infilterations..
3 .Chronic hepatitis.
4.Granulomas.
DARK LIVER

1.Liver parenchyma is of lower echogenicity than renal cortex
2. peri portal structures echoes are exaggerated.
3.Darkness of liver is due to more fluid present in parenchyma.

Causes are.

1Congestive cardiac failure.
2Acute infective hepatitis
3 Malignancy of liver
4 Lymph reticular tumour.

FATTY INFILTRATION OF LIVER
Causes are –
Diabetes Mellitus
Glycogen storage disease (Gauchers disease)
Obesity
Starvation & kwashiorkor
Alcoholic hepatitis
Others
Pregnancy
Corticosteroid
Hallothane / Tetracycline
Ulcerative Colitis

CIRRHOSIS OF LIVER
Sonological features of cirrhosis liver are very variable.
1. Liver may be enlarged with fatty change / may be normal in size /shrunken & scarred in late stages.
2. Highly echogenic(bright liver) seen in early cases where periportal structures are in apparent & appears like hepatic veins, while in others it may be normal.
3. Liver surface smooth but large regenerating nodule could be seen in post hepatitis cases.
4. Caudate lobe often enlarged which is a good index for cirrhosis of liver. Usually caudate lobe is half of the width of right lobe.
5. Ascites is seen which is transudate, no debris seen & bowel floats normally.
6. Portal vein more than 15 mm .
7. Splenic vein more than 10 mm in inspiration.
8. Portocaval anastomosis
· Oesophageal, splenic varices appears tortuous like bag of worms.
· Umbilical appears due to canalization of ligamentum teres.

AMOEBIC ABSCESS
Early cases are hyper echoic due to solid nature of abscess & it could be confused with meta static lesion of liver.
As liquefaction starts hypo echoic area appears due to collection of puss & necrotic debris. Occasionally mass is an echoic with floating debris inside cavity of abscess.
Initially abscess wall is irregular & shaggy but later it becomes smooth & outlined.
Post acoustic shadowing(PAS) often seen depending upon attenuation of puss.
Amoebic abscess cavity usually disappears in three months but occasionally it may last for one year or even more.
Usually amoebic abscess are single.
Site of the abscess is in right lobe superiorly close to diaphragm.

PYOGENIC ABSCESS
Pyogenic abscess are usually multiple.
Echo texture is similar to amoebic abscess varying from anechoic to highly echogenic.
Usually right lobe of liver due to streaming effect of portal vein.
Size vary from 1cm to any size.
Shape rounded are ovoid.
Walls irregular.
Posterior acoustic enhancement present.

HYDATID CYST

Commonly seen in right lobe of liver & is sub-capsular.
Well circumscribed, multilocular “cysts within cyst” i.e. daughter cysts within mother cyst.
Budding of germinal inner layer forming irregularities of cystic wall.
Hydatid sand(imperfectly formed daughter cyst) & calcification observed occasionally.
Many of daughter cysts are anechoic while some may have low level echoes due to debris.
If no daughter cysts seen then difficult to diagnose from simple cyst.

HEPATIC TUBERCULOSIS
1. Hepatic texture is non-homogeneous with scattered areas of increased & decreased reflectivity.
2. Some nodules could be located.
3. Caudate lobe may be enlarged.
4. Liver is enlarged.

HAEMANGIOMA
Cavernous type(where large sinusoidal blood vessels present)
Echo free focal lesions.
Irregular or lobulated wall.
No distal enhancement.
Occasionally complex lesion due to internal echoes are fluid- fluid level.

Capillary type(numerous small vessels present)
Echogenic(homogenous echo dense) masses.
Ill defined margin / sharply marginated.
Post acoustic shadowing present in masses more than 2.5 cm
Note- Haemangioma are to be confirmed by doppler study / angiography / biopsy(often catastrophic haemorrhage).

LIVER CELL ADENOMA
Solitary, marginated, encapsulated mass.
Common in woman taking oral contraceptives.
May present as palpable mass or pain in right hypochondrium.
If bleeding occurred it appears anechoic / hypo echoic or of greater density than surrounding liver parenchyma.