Gallbladder & Renal Ultrasound

Devesh Sharma

Gall Bladder

Probe position and orientation• Curvilinear or phased array probe• With the patient in the supine position, place the probe in the right upper

quadrant.• Once the gallbladder is clearly identified, obtain longitudinal and

transverse views of the gallbladder. • If stones are seen, obtain a dependent view (upright, standing, or left

lateral decubitus) to assess the mobility of the stones. • Use the liver as an acoustic window. If the gallbladder cannot be visualized

(because of bowel gas or a more lateral or cephalad location of the gallbladder), try moving laterally or superiorly. Moving the probe cephaladmay necessitate scanning through or between the right lower ribs; in such cases, consider switching to a phased array probe, which has a smaller footprint and is easier to position between the ribs.

• Suggested techniques– R Flank liver view– Flattening/sweep the probe (subcostal/xiphisternum)

Technique – Flank

R Flank

Technique – Subcostal Sweep

GB US LANDMARKS• Ideal view –

Exclamation ! = GB, Main hepatic fissure, CBD

• Identify for portal triad

• Long and short axis (Ideal view for GB wall thickness)

• 4x4 (GB wall < 4mm, CBD < 4mm)

Normal Gallbladder

• Thin, crisp wall (3mm)

• Anechoic lumen

Gallstones

Acute Cholecystitis

• 2 echogenic lines with hypoechoicarea between

• Pericholecystic fluid• \

Gallbladder Sludge

Pearls & Pitfalls

Duodenal Air

Polyps

Vessels

Renal Cyst

Ascites

WES Sign- Wall-Echo-Shadow

Patient Positioning

Biliary SystemNormal Ultrasound Appearances

– A thin, echogenic wall

– An anechoic lumen

– Posterior enhancement

– Bile ducts have echogenic walls

– An anechoic lumen

– Don’t always have posteriorenhancement

Biliary SystemGallstones

• Large, small, single or multiple

• Float, adhere or impact

• Sit in the neck

• Normally echogenic

• Posterior shadowing

• Patient position

• Machine settings

Biliary SystemAcute Cholecystitis

– A distended gallbladder – greater than 5 cm AP diameter

– The gallbladder may be irregular in outline and shape. It may be tense and round instead of it being pear shaped

– A wall thickness greater than 3mm

– An anechoic double-outline or halo in the wall suggesting oedema this can be focal or overall

– The presence of pericholecystic fluid

– 90% will have gallstones

– Colour Doppler may show enlargement of the cystic artery and therefore increased blood flow in the distal gallbladder wall

Biliary SystemBiliary Sludge

• Sludge is low level, homogeneous echoes that form a straight horizontal layer which move with patient movement but do not produce acoustic shadowing

• If it completely fills the gallbladder then it may be difficult to distinguish it from the surrounding liver parenchyma

• Sometimes sludge balls may be seen as mobile, round, echogenic masses that do not shadow

• Sludge can be present with gallstones• If the gain is too high sludge can be

mimicked.

Biliary SystemGallbladder Polyps

• A hyperechoic mass fixed to the inner

gallbladder wall of normal thickness

• There will be no posterior acoustic

shadowing

• Polyps will not move to an independent

location when the patient moves they

remain attached to their site

• They are usually multiple 2 – 10mm in size.

• May be on pedicle attached to wall

• Colour Doppler may show blood flow in

pedicle or in polyp itself

• The diagnosis of a polyp can be difficult

when the gallbladder is filled with sludge or

gallstones

Biliary SystemGallbladder carcinoma

• Solid irregular poorly defined polypoid mass, greater than 10mm in diameter filling the lumen of the gallbladder

• It may be difficult to distinguish between a primary carcinoma and metastases and stones may be the deciding factor as the latter is completely independent from stones and inflammation whilst in the former 80% will have stones

• Focal or diffuse wall thickening and may difficult to differentiate organ outline

• May see fluid levels representing necrosis

• Advanced disease will fill all of the lumen making it difficult to distinguish from surrounding liver tissue

• Colour Doppler will show an increase in vascularity throughout.

Biliary SystemBile duct obstruction

– Early intrahepatic duct dilatation when they measure more than 2mm

– Dilatation will be seen as ‘too many tubes’ representing dilated hepatic ducts running anterior to its portal vein – double barrel sign

– Irregular branching patterns

– Stellate confluence of ducts towards the porta hepatis

– Acoustic enhancement behind the dust as bile attenuates less than blood

– Common bile duct dilatation more than 6 to 8mm in diameter depending on the patient’s age proximal to the stenosis.

Biliary SystemGallbladder Variants

Biliary SystemReasons why gallbladder is not seen

– Not prepared properly

– Post cholecystectomy

– Absent gallbladder

– Sludge filled gallbladder

– Porcelain gallbladder

– Neoplasm

– Ectopic gallbladder

– Emphysematous gallbladder

– Bowel gas

Gallbladder Polyps

Wall Echo Shadow Complex

Duodenal Gas

US Gallbladder

– Focussed

– Faster

– Safer

– More accurate than CT and XRAY (sensitivity 88%, Specificity 80%)

Target Organ – Urinary Tract“KIDNEYS”

Urinary SystemUltrasound Appearances

• Renal capsule is a well defined echogenic line can be

lobulated

• The renal parenchyma is usually greater than 1.5 cms and

is made up of the cortex, medulla and pelvis.

• The cortex is homogenous and echogenic but less in

echogenicity to the liver, spleen pancreas and renal sinus

• In children the cortex appears less echogenic due to

perinephric fat surrounding the kidney.

• The central sinus of the kidney is homogenous with dense

echoes due to the renal fat which surrounds the blood

vessels and the collecting systems

• The medullary pyramids are usually less echogenic than

the surrounding cortex and are often seen as evenly-

distributed echo-poor oval or heart shaped structures.

• The ‘columns of Bertin’ can appear very prominent and

have often been mistakenly diagnoses as renal tumours

• The renal pelvis is a large triangular cavity medial to the

hilum

Urinary SystemUltrasound Appearances

• With the advent of colour Doppler and power

Doppler ultrasound the renal artery and vein can be

traced from the aorta and Interior Vena Cava

respectively on slim to average sized patients.

Within the kidney the segmental artery can be seen

dividing into the interlobar and then arcuate arteries

around the renal pyramids. The venous system can

also be demonstrated.

Urinary SystemUltrasound Appearances

• The normal ureter is not seen with ultrasound

• The bladder has a smooth, curved outline and the wall is a thin echogenic rim (2-3mm)

• It is symmetrical in shape and is almost square in the transverse section

• At the bladder base there are two small areas of focal thickness - the ureteric orifices

• The urine within it should be relatively echo free

Urinary System Sonographic

Anatomical Variations

• Dromedary hump

• Fetal lobulations

• Prominent column of Bertin

• Extra renal pelvis

Urinary SystemCongenital Anomalies

• Agenesis or hypoplasia of the kidneys

• Duplex collecting system

• Ectopic kidneys

• Horseshoe kidney

• PATIENT POSITION• Begin with the patient supine. Each kidney may also need to be examined in the

decubitus position. Raise the ipsilateral arm above the patient's head.

• TECHNIQUE• A comprehensive examination of the renal tracts should always include

assessment of the urinary bladder and, in males,the prostate.

Scan longitudinally right subcostally. Visualise the kidney inferior to the right lobe of the liver (RT), or spleen (LT). Place the probe between iliac crest and the lower costal margin to examine in the coronal plane. Ensure the kidney is thoroughly examined from edge to edge. Rotate into transverse. Scan from beyond the superior margin to inferior. Document the normal anatomy and any pathology found, including measurements and vascularity if indicated.

Emergency Room Utilisation

• Kidney Failure - hydronephrosis, size of kidneys, echogenicity, presence of bladder obstr.

• Renal trauma- lower sensitivity than CT, free fluid

• Renal colic – not as good as CT KUB/IVU

• Pyelonephritis – usually normal ultrasound

SEQUENCE of EVENTS

• Renal calculi formation• Ureterocaluli

– Size counts (3-5mm)– Renal Colic

• Bladder (Haematuria)• +- Ureteric obstruction

(hydroureter)• Obstructive uropathy• Hydronephrosis• Renal dysfunction/failure

Renal Anatomy

• Retroperitoneal at T12-L2 surrounded by capsule, fat and fascia

• Normal size 9 to 13cm

• Echogenicity

• Corticomedullary differentiation

Technique

L Kidney – post/cranial (hand resting on bed)

R Kidney – R flank subcostal

Technique- TS

Renal Calculi Can we visualise ?

• Bright calculi

• Posterior acoustic shadowing

Urinary SystemUrinary calculi

• A calculus will be seen as an echogenic mass which casts an acoustic shadow due to attenuation of the ultrasound beam

• The nature of the calculus will have no affect on whether it is seen or not

• Sometimes if the stone is small (less than 5mm) and lies within the renal sinus it may not be visualised due to both echogenicities being similar

• A calculi will only be seen in the ureter if it is distended in the upper and lower portions, the mid ureter is rarely seen due to overlying bowel loops

Urinary SystemUrinary calculi

• Calculi within the bladder will be seen as highly reflective masses that move when the patient alters their position. It is important to note that bladder tumours may calcify but unlike stones they do not move when the patient is turned

• Calcification of the bladder wall is rare and is usually due to calcification within a transitional cell carcinoma of the bladder.

Staghorn Calculus

Pitfall- Ureteric Calculi

• Don’t necessarily cause hydronephrosis, especially if dehydrated

Urinary SystemHydronephrosis

• The renal sinus will surround the sonolucent,

fluid filled calyces and renal pelvis

• The calyces can be traced into the renal pelvis

or may be so distended they cannot be

distinguished from the renal pelvis

• The renal parenchyma may be thinned to less

than 2.5 cm

• May be unilateral or bilateral depending on the

site of obstruction

• The ureters may be dilated and seen down to

the area of obstruction

• In cases where the hydronephrosis has been

long term the dilation is often still present

when the site of obstruction has been

removed. But this must be proven not to be

due to reflux

• A pelvi-ureteric junction (PUJ) obstruction will

not show dilated ureters

Hydronephrosis

Mild Hydronephrosis

• Hypoechoic area in the bright renal pelvis fat

Moderate Hydronephrosis

Severe Hydronephrosis

Pitfalls

Renal Trauma

• Minor- normal ultrasound

• Major-pericapsularor free fluid

• Catastrophic- free fluid. May see lesion

Renal Haemorrhage

Renal Cysts

• >50% over age 50

• Anaechoic

• Posterior acoustic enhancement

• Sharply defined walls

• Age <40 consider referral for departmental scan

Urinary SystemRenal Cysts

• They can be single or multiple and variable in size

• Simple cysts will have smooth, thin walls, be round or oval with no internal echoes and have posterior enhancement.

• Thin septa can sometimes be seen within the cyst usually due to haemorrhage, but if there are multiple thick septa, irregular walls, solid components or calcification the cyst needs to be further investigated

• Peripelvic cysts should always be distinguished from a dilated renal pelvis or calyx.

• Multiple simple cysts

• Complex cysts

Urinary SystemOther Cystic Conditions

Urinary System Other Cystic Conditions

Adult polycystic disease• Both kidneys are always affected.

• The kidneys are enlarged

• Parenchyma is distorted by cysts that

have an irregular outline

• The cysts vary in size and shape

• Cysts cannot be joined together

therefore excluding hydronephrosis.

Urinary System Other Cystic Conditions

Infantile polycystic kidney disease

• Both kidneys are enlarged

• Hyperechoic cortex. No cysts are see as they

are tiny but cystic interfaces cause an increase

in echogenicity

• Hyperechoic liver due to fibrosis

Urinary System Other Cystic Conditions

Multicystic dysplastic kidney disease

• Unilateral (hopefully)

• Postnatally the affected kidney is small or absent

• Multiple small cysts in children may be seen or a

calcified shell in adults

• Cysts of random location within parenchyma

• Cysts cannot be joined together therefore

excluding hydronephrosis.

MH

• 5 yr boy,

• fell from scooter onto right side earlier that day.

• frank haematuria

• Focused uss: 8.64 cm size mass arising from upper pole right kidney.

• Probable Wilm’s tumour.

Urinary System

Malignant Renal TumoursRenal cell carcinoma

• Irregular borders extending beyond the outline of the kidney

• Solid mass

• Can be hypoechoic, hyperechoic, complex or isoechoic when compared to surrounding parenchyma

• Metastatic extension into IVC, renal vein or liver

• Colour Doppler will show

increased blood flow.

Urinary System

Malignant Renal TumoursRenal cell carcinoma

Urinary System

Malignant Renal Tumours

Transitional cell carcinoma

• Hypoechoic solid mass within the renal sinus

• Irregular poorly defined borders

• No posterior acoustic shadowing

• May cause secondary hydronephrosis

Urinary System

Malignant Renal Tumours

Wilms' tumour (nephroblastoma)

• Usually unilateral with 10% bilateral

• Large, predominantly solid, well defined mass

• Variable echogenicity with anechoic areas of

necrosis and haemorrhage

• May displace pelvicalyceal system

• Metastatic extension into IVC, renal vein or

liver

Bladder

• Thin walled structure

• 3 muscle layers and mucosa

• Anechoic interior

• Posterior acoustic enhancement

Urinary Retention

Bladder Debris

Bladder Cancer in Diverticulum

Bladder stone

Pitfall- Ovarian Cyst

Urinary System

Urinary SystemBladder Tumours

Transitional, adeno or squamouscell carcinomas

• Generally small in size

• Localised thickening of the bladder wall

• An irregular, echogenic, polypoid mass arising from the wall and projecting into the bladder lumen

• Dilatation of the ureters and upper urinary tract if it is causing an obstruction

• Echogenic line around bladder is absent when the tumour invades the wall

LE

• 41 yr old Urology pt: in retention, had TURBT few days previously.

• Clot retention

Summary

• Not a replacement for formal renal radiology

• Check the size of the bladder when diagnosing hydronephrosis

• No hydronephrosis, you may still have ureteric calculi

Wrap Up !

• Rapid assessment

• Follow a good history and examination

• Augment blood results

• “Rule in“ vs “Rule out”

• Follow with formal radiology