Doppler

waveforms

of

the

ureteric

jet

an

overview

and

implications

for

the

presence

of

a

functional

sphincter

at

the

vesicoureteric

junction

This

paper

is

a

comprehensive

review

of

the

Doppler

waveform

appearance

of

ureteric

jets

Six

jet

waveform

patterns

have

been

identified

monophasic

biphasic

triphasic

polyphasic

square

and

continuous

Details

of

the

physical

properties

of

jet

patterns

and

their

changes

under

various

physiological

conditions

are

illustrated

The

immature

monophasic

ureteric

jet

pattern

is

common

in

infancy

and

early

childhood

up

to

around

years

of

age

This

pattern

is

also

noted

to

have

a

high

incidence

in

older

children

with

urinary

tract

infection/vesicoureteric

reflux

nocturnal

enuresis

and

in

other

special

physiological

conditions

such

as

in

children

undergoing

general

anaesthesia

in

women

during

pregnancy

and

in

patients

who

have

had

ureteric

transplantation

A

hypothesis

of

dual

myogenic

and

neurogenic

components

is

proposed

to

explain

the

mode

of

action

of

the

vesicoureteric

junction

-LRB-

VUJ

-RRB-

The

implication

of

this

hypothesis

is

that

it

alters

the

scientific

basis

of

the

understanding

of

the

VUJ

Furthermore

the

application

of

colour

Doppler

US

to

ureteric

jets

may

provide

a

non-invasive

technique

to

study

the

physiology

or

pathophysiology

of

the

VUJ

in

humans

This

might

shed

light

on

new

novel

approaches

to

the

monitoring

and

treatment

of

diseases

related

to

VUJ

function

Introduction

When

the

bolus

of

urine

being

transmitted

through

the

ureter

reaches

the

terminal

portion

it

is

ejected

forcefully

into

the

bladder

through

the

vesicoureteric

junction

-LRB-

VUJ

-RRB-

This

creates

a

jet

of

urine

that

can

be

seen

within

the

urinary

bladder

during

cystoscopy

and

grey-scale

ultrasonography

-LRB-

US

-RRB-

Ureteric

jets

are

also

occasionally

visible

during

intravenous

urography

-LRB-

IVU

-RRB-

and

voiding

cystourethrography

-LRB-

VCU

-RRB-

In

grey-scale

real-time

US

imaging

the

jet

can

be

visualized

as

a

stream

or

burst

of

low-intensity

echoes

emerging

from

the

ureteric

orifice

Each

ureteric

jet

usually

lasts

for

few

seconds

and

is

fast

enough

to

produce

a

frequency

shift

therefore

the

ureteric

jet

can

be

demonstrated

by

colour

Doppler

US

Colour

Doppler

US

is

in

fact

the

easiest

method

for

demonstrating

the

jet

It

is

also

amenable

to

further

characterization

using

a

pulse-wave

Doppler

waveform

The

US

appearance

of

the

jet

has

been

documented

in

a

number

of

studies

and

the

jet

can

be

consistently

demonstrated

in

both

humans

-LSB-

-RSB-

and

animals

such

as

the

dog

-LSB-

-RSB-

This

review

is

based

on

a

number

of

previous

studies

that

involve

US

scanning

of

a

total

of

subjects

which

include

a

normal

population

of

subjects

The

characteristics

of

ureteric

jets

in

a

normal

population

of

subjects

are

described

and

the

effect

of

age

gender

and

bladder-filling

-LRB-

based

on

a

subgroup

of

normal

adult

females

-RRB-

are

discussed

A

summary

of

jet

patterns

seen

in

children

with

urinary

tract

infection/vesicoureteric

reflux

-LRB-

VUR

-RRB-

-LRB-

n

-RRB-

-LSB-

-RSB-

and

nocturnal

enuresis

-LRB-

n

-RRB-

-LSB-

-RSB-

is

also

presented

Special

groups

including

pregnant

women

-LRB-

n

-RRB-

-LSB-

-RSB-

anaesthetized

children

-LRB-

n

-RRB-

-LSB-

-RSB-

and

subjects

with

ureteric

transplantation

-LRB-

n

-RRB-

-LSB-

-RSB-

are

also

discussed

to

look

at

changes

of

ureteric

jet

patterns

under

specific

physiological

conditions

Overall

the

observations

suggest

a

possible

correlation

of

different

jet

patterns

with

functional

sphincteric

action

of

the

VUJ

A

hypothesis

of

dual

myogenic

and

neurogenic

components

is

proposed

to

explain

the

mode

of

action

of

the

VUJ

Discussion

Basic

ureteric

jet

patterns

on

Doppler

US

Jequier

et

al.

-LSB-

-RSB-

were

the

first

to

describe

the

ureteric

jet

In

their

study

of

children

they

demonstrated

that

ureteric

jets

had

both

crescendo

and

decrescendo

forms

The

jet

waveforms

ranged

from

a

single

to

as

many

as

four

humps

Cox

et

al.

-LSB-

-RSB-

noted

that

the

number

of

peaks

-LRB-

the

humps

of

Jequier

et

al.

-RRB-

in

the

ureteric

jet

varied

from

one

to

four

while

Wu

et

al.

-LSB-

-RSB-

found

only

two

or

three

peaks

Both

the

latter

studies

involved

only

adults

To

the

best

of

our

knowledge

ours

is

the

only

group

that

has

studied

in

detail

ureteric

jet

patterns

in

a

cohort

of

subjects

with

a

wide

age

range

including

a

large

paediatric

population

Six

basic

patterns

have

been

identified

according

to

the

number

of

peaks

within

a

single

ureteric

jet

monophasic

biphasic

triphasic

polyphasic

square

and

continuous

-LSB-

-RSB-

-LRB-

Fig.

-RRB-

Among

these

the

square

and

continuous

waveforms

represent

modified

waveforms

under

the

state

of

forced

diuresis

and

they

are

deliberately

avoided

in

most

of

the

study

analysis

The

biphasic

triphasic

and

polyphasic

waveforms

are

grouped

under

the

category

of

mature

complex

jets

while

the

monophasic

jet

is

classified

as

the

immature

jet

We

have

shown

that

the

majority

of

the

population

have

a

complex

mature

waveform

of

the

ureteric

jet

while

the

immature

monophasic

waveform

has

a

significantly

higher

incidence

in

young

children

This

is

discussed

in

more

detail

below

Fig.

patterns

of

the

ureteric

jet

a

monophasic

b

biphasic

c

triphasic

d

polyphasic

e

square

and

f

continuous

The

initial

slope

duration

and

maximum

velocity

-LRB-

peak

velocity

-RRB-

of

the

strongest

jet

are

measured

on

every

Doppler

waveform

for

quantification

purposes

Significant

differences

have

been

found

in

the

above

physical

parameters

among

the

four

jet

patterns

monophasic

biphasic

triphasic

and

polyphasic

The

monophasic

jet

has

the

shortest

duration

lowest

velocity

and

smallest

initial

slope

-LSB-

-RSB-

Occasional

modification

features

of

the

ureteric

jet

Some

interesting

features

have

been

observed

in

the

jet

patterns

of

some

normal

subjects

These

features

include

-LRB-

a

-RRB-

the

presence

of

breaks

-LRB-

b

-RRB-

a

multispike

pattern

and

-LRB-

c

-RRB-

change

of

angle

of

the

jet

between

the

beginning

and

the

end

The

number

of

cases

with

the

above

features

is

too

small

for

statistical

analysis

however

we

sought

to

describe

them

in

detail

for

completeness

of

the

whole

spectrum

of

ureteric

jet

patterns

These

features

also

provide

indirect

supportive

evidence

for

the

hypothesis

of

functional

sphincteric

action

at

the

VUJ

and

are

discussed

further

in

the

final

section

Breaks

The

presence

of

break

is

defined

as

the

total

absence

of

Doppler

signal

between

peaks

within

a

single

ureteric

jet

waveform

-LRB-

Fig.

-RRB-

Breaks

were

identified

in

-LRB-

ureters

-RRB-

of

the

study

population

Comparing

different

groups

of

subjects

it

has

been

found

that

most

breaks

occur

in

adult

females

when

their

bladder

is

at

maximum

capacity

i.e.

when

the

subjects

experience

an

urgent

desire

to

micturate

-LRB-

of

adult

females

P

chi

squared

test

-RRB-

Fig.

within

a

ureteric

jet

Multispike

pattern

A

multispike

pattern

is

defined

as

the

pulsations

noted

within

a

single

jet

waveform

as

the

result

of

pulsation

transmitted

from

adjacent

arteries

-LRB-

Fig.

-RRB-

The

incidence

of

a

multispike

pattern

was

found

to

be

-LRB-

-RRB-

in

the

normal

population

and

is

more

commonly

observed

when

the

bladder

is

extremely

full

-LRB-

forced

diuresis

-RRB-

Fig.

multispike

pattern

of

a

ureteric

jet

Change

in

angle

of

the

jet

A

change

in

the

angle

within

a

single

jet

waveform

is

illustrated

given

in

Fig.

The

incidence

of

change

in

angle

of

the

ureteric

jet

in

the

whole

normal

population

was

-LRB-

-RRB-

Fig.

in

angle

of

the

ureteric

jet

-LRB-

a

-RRB-

at

the

beginning

and

-LRB-

b

-RRB-

at

the

end

of

the

ureteric

waveform

Ureteric

jet

pattern

and

physical

properties

of

jets

in

normal

subjects

General

properties

Direction

of

flow

Dubbins

et

al.

-LSB-

-RSB-

and

Elejalde

and

de

Elejalde

-LSB-

-RSB-

have

found

on

both

US

and

MRI

that

the

ureteric

jet

is

usually

directed

anteriorly

or

anteromedially

-LRB-

with

or

without

crossing

of

the

jets

-RRB-

while

others

have

found

ureteric

jets

directed

in

a

more

vertical

direction

or

perpendicular

to

the

bladder

base

-LSB-

-RSB-

Our

US

findings

are

in

agreement

with

the

above

on

the

ureteric

jet

direction

of

flow

Mean

jet

velocity

In

our

studies

the

mean

velocity

of

ureteric

jets

in

children

was

found

to

be

cm/s

for

the

monophasic

pattern

and

cm/s

for

the

complex

pattern

-LRB-

Tables

and

-RRB-

These

values

are

higher

than

those

reported

previously

The

mean

jet

velocity

previously

reported

in

children

aged

from

days

to

years

varies

between

and

cm/s

-LSB-

-RSB-

The

discrepancy

between

the

findings

of

our

study

and

those

of

previous

studies

can

be

explained

by

different

proportions

of

children

of

different

ages

The

mean

velocity

in

adults

in

our

cohort

was

found

to

be

cm/s

for

the

monophasic

pattern

and

cm/s

for

the

complex

pattern

These

values

are

similar

to

those

reported

previously

-LSB-

-RSB-

Table

values

of

jet

parameters

in

children

and

adults

with

the

monophasic

pattern

Right

sideLeft

sideChildrenAdultsP

valueChildrenAdultsP

valueNumber

of

ureteric

slope

-LRB-

cm

s

-RRB-

Velocity

-LRB-

cm

s

-RRB-

Duration

-LRB-

s

-RRB-

Table

values

of

jet

parameters

in

children

and

adults

with

the

complex

pattern

Right

sideLeft

sideChildrenAdultsP

valueChildrenAdultsP

valueNumber

of

ureteric

slope

-LRB-

cm

s

-RRB-

Velocity

-LRB-

cm

s

-RRB-

Duration

-LRB-

s

-RRB-

Mean

jet

duration

In

our

studies

the

mean

jet

duration

in

children

was

s

for

the

monophasic

pattern

and

s

for

the

complex

pattern

In

adults

the

mean

jet

duration

was

s

for

the

monophasic

pattern

and

s

for

the

complex

pattern

-LRB-

Tables

and

-RRB-

These

values

are

similar

to

those

reported

previously

In

adults

previously

reported

jet

durations

range

from

to

s

-LSB-

-RSB-

while

in

children

previously

reported

mean

jet

durations

in

two

different

series

were

s

-LSB-

-RSB-

and

s

-LSB-

-RSB-

Laterality

difference

in

ureteric

jets

In

general

there

are

no

significant

differences

in

waveform

pattern

initial

slope

velocity

and

duration

of

ureteric

jets

between

the

right

and

left

sides

in

both

children

and

adults

This

is

in

agreement

with

the

study

of

Matsuda

and

Saitoh

-LSB-

-RSB-

There

were

two

exceptions

in

our

cohort

which

might

not

have

clinical

significance

Boys

were

found

to

have

a

higher

incidence

of

the

monophasic

waveform

in

jets

on

the

left

side

compared

with

girls

-LRB-

P

chi-squared

test

Table

-RRB-

while

adult

males

have

a

lower

velocity

on

the

left

than

the

right

-LRB-

P

paired

sample

T-test

-RRB-

-LRB-

Table

-RRB-

Table

patterns

in

children

and

adults

in

relation

to

sex

-LRB-

total

of

ureteric

jets

in

subjects

-RRB-

ChildrenAdultsFemaleMaleFemaleMaleRightLeftRightLeftRightLeftRightLeftNumber

of

ureteric

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Table

values

of

jet

parameters

in

children

and

adults

in

relation

to

sex

of

ureteric

slope

-LRB-

cm

s

-RRB-

290.73261.06264.22264.31268.12274.72271.93234.07

Velocity

-LRB-

cm

s

-RRB-

56.3157.0255.7257.6069.9468.8494.0180.82

Duration

-LRB-

s

-RRB-

Effect

of

age

on

ureteric

jets

The

distribution

of

the

four

basic

patterns

-LRB-

monophasic

biphasic

triphasic

polyphasic

-RRB-

among

children

and

adults

has

been

previously

described

by

our

group

We

have

found

a

strikingly

larger

proportion

of

monophasic

waveforms

in

children

than

in

adults

in

a

population

of

subjects

-LSB-

-RSB-

In

this

review

the

above

finding

is

substantiated

after

expanding

the

study

population

to

normal

subjects

Children

are

found

to

have

a

higher

incidence

of

the

immature

pattern

than

adults

The

incidences

of

the

monophasic

waveform

in

children

and

adults

are

and

on

the

right

side

and

and

on

the

left

side

respectively

-LRB-

P

chi-squared

test

Table

-RRB-

This

immature

pattern

occurs

constantly

in

the

first

months

of

life

-LSB-

-RSB-

In

our

previously

reported

cohort

the

immature

monophasic

pattern

in

children

changed

to

a

mature

complex

pattern

at

a

mean

age

of

years

which

probably

reflects

the

mean

age

of

VUJ

maturity

in

general

There

is

no

significant

gender

difference

for

the

mean

age

of

VUJ

maturity

in

children

boys

show

VUJ

maturity

at

a

mean

age

of

years

and

girls

at

a

mean

age

of

years

-LRB-

P

simple

Z

test

-RRB-

-LSB-

-RSB-

Adults

have

higher

velocity

-LRB-

P

independent

sample

t

test

-RRB-

and

longer

duration

of

the

ureteric

jet

-LRB-

P

independent

sample

t

test

-RRB-

than

children

in

both

the

monophasic

and

complex

patterns

This

finding

has

also

been

reported

by

Matsuda

and

Saitoh

-LSB-

-RSB-

suggesting

that

the

stroke

volume

of

urine

in

children

is

less

than

that

in

adults

The

initial

slope

of

the

ureteric

jet

however

shows

no

significant

difference

between

children

and

adults

-LRB-

all

P

independent

sample

t

test

Tables

and

-RRB-

Effect

of

gender

on

ureteric

jets

In

the

adult

population

males

have

a

higher

incidence

of

the

polyphasic

waveform

than

females

-LRB-

P

for

both

right

and

left

sides

chi-squared

test

Table

-RRB-

Male

subjects

also

have

a

higher

velocity

-LRB-

P

for

both

sides

independent

sample

t

test

-RRB-

and

longer

duration

of

the

ureteric

jet

than

females

-LRB-

P

for

both

sides

independent

sample

t

test

Table

-RRB-

In

children

however

no

significant

differences

in

velocity

duration

initial

slope

or

number

of

peaks

within

a

single

jet

was

observed

between

boys

and

girls

-LRB-

all

P

chi-squared

and

independent

sample

t

test

Tables

and

-RRB-

Table

of

monophasic

jet

in

children

and

adults

-LRB-

total

of

ureteric

jets

in

subjects

-RRB-

Note

that

the

total

number

of

ureteric

jets

is

less

than

double

the

number

of

subjects

as

jets

in

some

subjects

could

not

be

satisfactorily

demonstrated

on

both

sides

by

Doppler

US

Right

sideLeft

sideChildrenAdultsP

valueChildrenAdultsP

valueNumber

of

ureteric

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Effect

of

bladder

filling

status

on

ureteric

jets

In

a

subgroup

of

adult

females

we

demonstrated

how

jet

patterns

are

affected

by

different

bladder

filling

status

Jet

characteristics

are

compared

between

two

different

time

intervals

-LRB-

-RRB-

when

bladder

volume

was

small

and

rate

of

diuresis

was

low

and

-LRB-

-RRB-

when

bladder

volume

was

large

and

rate

of

diuresis

more

active

We

found

that

of

the

subjects

showed

no

change

in

the

number

of

peaks

within

a

single

jet

waveform

showed

a

decrease

and

showed

an

increase

and

had

square

and

continuous

jet

patterns

when

the

bladder

was

very

full

-LSB-

-RSB-

Among

the

group

with

changes

in

the

number

of

peaks

showed

a

change

from

a

monophasic

to

a

complex

pattern

and

showed

a

change

from

a

complex

to

a

monophasic

pattern

In

all

subjects

the

initial

slope

velocity

and

duration

of

the

jet

were

not

affected

by

different

stages

of

bladder

filling

-LRB-

all

P

paired

sample

t

test

Table

-RRB-

Even

though

bladder

filling

was

shown

to

have

little

effect

on

whether

the

subjects

had

an

immature

or

complex

pattern

we

standardized

the

protocol

of

bladder

filling

in

all

our

subsequent

Doppler

US

studies

of

ureteric

jets

Scanning

was

started

in

most

subjects

min

after

water

intake

because

the

jet

frequency

is

reasonably

high

at

that

time

while

the

bladder

is

not

yet

too

distended

to

make

the

subject

feel

uncomfortable

Table

values

of

jet

parameters

in

subjects

under

different

stages

of

bladder

filling

Only

the

jet

on

the

right

side

is

shown

for

comparison

as

there

was

no

significant

difference

between

the

two

sidesJet

parameterBladder

statusP

valueNot

fullMaximally

fullInitial

slope

-LRB-

cm

s

-RRB-

Velocity

-LRB-

cm

s

-RRB-

Duration

-LRB-

s

-RRB-

Characteristics

of

ureteric

jet

under

specific

physiological

conditions

Pregnancy

-LRB-

physiological

-RRB-

A

total

of

pregnant

women

and

non-pregnant

women

were

investigated

The

occurrence

of

the

monophasic

waveform

was

significantly

higher

in

the

pregnant

women

than

in

the

non-pregnant

women

-LRB-

and

at

weeks

gestation

weeks

gestation

and

months

postpartum

respectively

vs.

in

the

non-pregnant

women

-RRB-

-LSB-

-RSB-

General

anaesthesia

-LRB-

pharmacological

-RRB-

Our

previous

study

has

documented

loss

of

the

complex

jet

pattern

after

general

anaesthesia

A

total

of

children

undergoing

surgery

under

general

anaesthesia

were

recruited

Before

anaesthesia

of

them

showed

a

complex

pattern

and

two

showed

a

monophasic

pattern

After

anaesthesia

all

showed

a

monophasic

waveform

-LSB-

-RSB-

Ureteric

transplantation

following

renal

transplantation

Our

previous

study

has

shown

that

transplanted

ureters

do

not

have

the

normal

regulatory

function

at

the

VUJ

but

inherent

peristalsis

is

retained

-LSB-

-RSB-

From

a

comparison

of

transplant

patients

and

healthy

subjects

we

found

that

the

Doppler

waveforms

of

transplanted

ureters

are

distinctly

different

from

those

of

healthy

adult

ureters

Basically

only

two

patterns

were

identified

from

transplanted

ureters

more

commonly

a

short

monophasic

waveform

-LRB-

vs.

in

the

health

ureters

-RRB-

and

less

commonly

a

longer

multiphase

pattern

that

does

not

resemble

the

patterns

of

the

healthy

ureter

Ureteric

jet

characteristics

in

paediatric

conditions

Literature

review

Previous

studies

have

attempted

to

relate

the

ureteric

jet

seen

during

IVU

in

UTI

VUR

and

bladder

neck

obstruction

The

studies

of

Kalmon

et

al.

-LSB-

-RSB-

and

Nevin

et

al.

-LSB-

-RSB-

have

suggested

that

identification

of

ureteric

jets

in

IVU

studies

do

not

exclude

VUR

but

Kuhns

et

al.

-LSB-

-RSB-

found

an

association

between

the

jet

sign

and

absence

of

VUR

They

postulated

that

the

jet

sign

is

produced

by

peristalsis

through

the

ureteric

sphincter

There

might

be

an

abnormal

increase

in

the

intravesical

volume

and

pressure

in

the

presence

of

reflux

thus

preventing

ureteric

peristalsis

so

that

no

jet

can

be

seen

Eklöf

and

Johanson

-LSB-

-RSB-

however

disagreed

with

this

hypothesis

finding

a

lower

incidence

of

visible

jet

in

subjects

without

radiological

proof

of

VUR

-LRB-

compared

with

in

the

study

of

Kuhns

et

al.

-RRB-

Although

infrequent

significant

ipsilateral

VUR

is

observed

even

when

a

ureteric

jet

is

detected

-LRB-

-LSB-

-RSB-

vs.

-LSB-

-RSB-

-RRB-

Eklöf

and

Johanson

-LSB-

-RSB-

concluded

therefore

that

the

low

rate

of

bilateral

jets

detected

on

IVU

restricts

the

potential

clinical

value

of

jet

detection

on

IVU

as

an

indicator

of

the

absence

of

gross

VUR

and

that

voiding

cystourethrography

is

necessary

in

the

radiological

work-up

of

children

with

UTI

Marshall

et

al.

-LSB-

-RSB-

agreed

with

the

view

of

Kuhns

et

al.

-LSB-

-RSB-

that

visualization

of

a

ureteric

jet

on

IVU

should

not

exclude

VUR

In

addition

they

found

a

strong

correlation

between

relatively

lateral

positioning

of

the

orifice

and

the

presence

of

VUR

The

mean

velocity

of

the

ureteric

jet

is

not

related

to

VUR

A

midline-to-orifice

distance

of

mm

has

been

proposed

as

the

cut-off

for

predicting

VUR

The

more

laterally

positioned

the

ureteric

orifice

the

more

likely

it

is

that

reflux

will

occur

-LSB-

-RSB-

Subsequent

studies

largely

agree

with

the

concept

that

the

ureteric

jet

is

just

a

normal

physiological

phenomenon

Gothlin

-LSB-

-RSB-

found

that

the

ureteric

jet

can

be

identified

in

subjects

with

and

without

UTI

Neither

sex

nor

age

has

an

effect

on

jet

visualization

He

therefore

concluded

that

the

jet

is

just

a

physiological

phenomenon

and

the

roentgenographic

finding

is

normal

There

are

a

number

of

previous

studies

evaluating

characteristics

of

the

ureteric

jet

based

on

Doppler

US

Jequier

et

al.

-LSB-

-RSB-

found

that

the

Doppler

waveform

parameters

of

jet

direction

duration

frequency

velocity

and

shape

do

not

help

in

predicting

VUR

A

lateral

ureteric

orifice

is

not

seen

in

normal

patients

but

is

identified

in

subjects

with

VUR

and

other

urinary

tract

disorders

Gudinchet

et

al.

-LSB-

-RSB-

found

no

difference

between

refluxing

and

non-refluxing

ureters

with

regard

to

ureteric

jet

length

angle

and

midline-to-orifice

distance

They

concluded

that

these

parameters

can

not

be

used

to

predict

recurrence

of

reflux

in

children

after

endoscopic

subureteric

collagen

injection

-LRB-

SCIN

-RRB-

for

the

treatment

of

VUR

In

two

recent

studies

carried

out

by

our

group

we

found

a

high

correlation

between

the

immature

monophasic

jet

pattern

in

children

with

specific

urinary

disease

entities

The

details

are

discussed

in

the

following

sections

Children

with

VUR

and

UTI

Ureteric

jets

of

healthy

children

and

children

with

UTI

were

studied

The

incidence

of

monophasic

jet

-LRB-

immature

pattern

-RRB-

was

in

healthy

children

overall

but

varied

greatly

according

to

age

The

immature

pattern

was

universal

in

the

first

months

of

life

but

was

markedly

reduced

to

below

in

late

childhood

This

immature

pattern

was

more

commonly

seen

in

children

with

UTI

-LRB-

-RRB-

and

VUR

-LRB-

-RRB-

than

in

healthy

controls

of

the

same

age

-LSB-

-RSB-

Children

with

nocturnal

enuresis

A

comparison

was

made

between

children

presenting

with

primary

nocturnal

enuresis

and

age-matched

normal

controls

The

incidence

of

immature

monophasic

jet

was

significantly

greater

in

enuretic

children

-LRB-

in

both

sides

-RRB-

than

in

normal

children

-LRB-

on

the

right

side

and

on

the

left

side

-RRB-

Furthermore

the

immature

waveform

was

more

commonly

seen

in

the

enuretic

group

with

a

markedly

thickened

bladder

wall

and

multiple

urodynamic

abnormalities

-LSB-

-RSB-

Taking

all

the

observations

together

we

postulate

a

hypothesis

concerning

the

mode

of

action

of

the

VUJ

as

illustrated

in

the

last

section

Hypothesis

of

an

active

sphincter

at

the

VUJ

There

has

been

controversy

regarding

the

anatomy

and

function

of

the

VUJ

for

a

long

time

There

are

three

schools

of

thought

for

the

antireflux

mechanism

at

the

VUJ

In

the

first

theory

the

VUJ

is

thought

to

be

governed

by

a

passive

valve

mechanism

dependent

on

the

length

and

obliquity

of

the

intravesical

ureter

-LSB-

-RSB-

In

the

second

theory

the

VUJ

is

considered

to

possess

mixed

active

and

passive

valvular

action

In

addition

to

the

anatomical

factors

the

distal

ureter

also

shows

antireflux

ureteric

peristaltic

activity

so

that

contraction

of

the

ureter

can

prevent

retrograde

leakage

of

the

intraluminal

contents

-LSB-

-RSB-

In

the

third

theory

the

VUJ

is

considered

to

be

able

to

act

as

a

sphincter

Noordzij

and

Dabhoiwala

-LSB-

-RSB-

have

proposed

a

sphincteric

function

for

the

VUJ

which

might

be

activated

by

the

intrinsic

muscular

meshwork

of

the

trigonal

region

of

the

bladder

complementing

a

purely

passive

antireflux

mechanism

Taking

into

consideration

all

the

features

observed

in

previous

Doppler

US

studies

of

the

ureteric

jet

we

postulate

that

the

human

VUJ

can

act

as

a

functional

sphincter

Only

a

monophasic

ureteric

peristaltic

wave

is

demonstrated

by

M-mode

study

of

the

ureter

-LSB-

-RSB-

while

the

waveform

of

the

ureteric

jet

emanating

from

the

VUJ

becomes

more

complex

in

pattern

Because

the

waveform

of

the

ureteric

jet

is

modified

an

active

sphincter

mechanism

is

probably

present

at

the

VUJ

-LSB-

-RSB-

Because

the

VUJ

shows

sphincteric

activity

different

patterns

of

ureteric

jet

can

be

identified

under

different

physiological

and

pathological

conditions

with

occasional

modifications

We

hypothesize

that

dual

components

are

present

regarding

the

mode

of

action

in

the

active

functional

sphincter

The

first

component

is

the

myogenic

-LRB-

primary

or

immature

-RRB-

and

the

second

component

is

neural

-LRB-

secondary

or

mature

-RRB-

The

distal

ureteric

muscle

and

possibly

part

of

the

detrusor

muscle

may

contribute

to

the

functional

sphincteric

action

at

the

VUJ

We

postulate

that

the

monophasic

jet

pattern

is

the

result

of

contraction

caused

by

the

myogenic

component

of

the

VUJ

while

the

complex

pattern

is

the

result

of

modulation

of

the

myogenic

component

of

the

jet

by

the

neural

component

in

response

to

the

distal

intraureteric

pressure

The

mode

of

the

functional

sphincteric

action

of

the

VUJ

and

the

subsequent

ureteric

jet

waveform

vary

depending

upon

whether

or

not

the

neural

component

is

active

In

normal

adults

and

in

children

reaching

a

certain

age

of

maturity

the

neural

component

modulates

the

myogenic

component

and

complex

patterns

can

thus

be

seen

When

the

neural

component

is

absent

for

example

in

a

small

immature

child

under

general

anaesthesia

or

in

certain

pathological

conditions

only

the

myogenic

component

is

functioning

and

thus

the

jet

pattern

reverses

to

the

monophasic

pattern

In

renal

transplantation

patients

with

ureteric

reimplantation

the

normal

VUJ

mechanism

in

the

transplanted

ureter

is

completely

lost

and

the

ureteric

jet

patterns

observed

are

completely

different

from

the

patterns

obtained

from

the

native

VUJ

in

normal

subjects

-LSB-

-RSB-

These

distinct

patterns

could

be

explained

by

loss

of

both

the

normal

myogenic

and

the

neural

components

of

the

sphincter

action

Although

the

neural

component

governing

the

ureteric

jet

pattern

is

either

present

-LRB-

resulting

in

a

complex

pattern

-RRB-

or

absent

-LRB-

resulting

in

a

monophasic

pattern

-RRB-

the

characteristics

-LRB-

initial

slope

velocity

and

duration

-RRB-

of

the

monophasic

and

complex

pattern

within

the

same

age

group

remain

distinct

Although

there

is

a

trend

for

a

longer

duration

and

higher

peak

velocity

of

the

ureteric

jet

with

increasing

age

this

could

be

explained

by

a

larger

bolus

of

urine

in

each

jet

in

adults

than

in

smaller

children

The

neural

component

governing

the

sphincteric

action

of

the

VUJ

appears

to

be

affected

under

various

physiological

and

pathological

conditions

We

have

observed

a

marked

increase

in

the

incidence

of

a

monophasic

jet

pattern

in

pregnant

women

However

for

those

pregnant

women

who

retain

the

complex

jet

pattern

the

characteristics

of

the

complex

waveform

remain

similar

to

those

seen

in

non-pregnant

women

-LSB-

-RSB-

The

above

observation

suggests

that

the

neural

mechanism

of

the

VUJ

is

lost

in

some

pregnant

women

but

the

underlying

reason

remains

obscure

In

subjects

undergoing

general

anaesthesia

the

ureteric

jet

waveforms

revert

to

the

monophasic

pattern

with

no

difference

in

initial

slope

velocity

and

duration

of

the

waveform

when

compared

with

the

normal

population

-LSB-

-RSB-

This

suggests

that

the

ureteric

jet

in

anaesthetized

subjects

is

under

myogenic

influence

solely

while

the

neurogenic

influence

is

temporarily

suspended

Histochemical

study

of

the

VUJ

-LSB-

-RSB-

has

shown

the

muscular

components

of

the

VUJ

to

be

innervated

by

both

adrenergic

and

cholinergic

nerves

However

because

several

drugs

were

simultaneously

administered

during

general

anaesthesia

in

our

small

cohort

the

exact

pharmacological

action

of

these

drugs

on

the

neurogenic

pathway

could

not

be

clearly

determined

The

presence

of

VUR

is

highly

correlated

with

the

immature

monophasic

waveform

-LSB-

-RSB-

This

observation

suggests

that

the

complex

jet

pattern

is

associated

with

a

more

efficient

antireflux

mechanism

than

the

simple

monophasic

waveform

that

is

more

primitive

or

immature

In

those

children

with

UTI

but

without

VUR

a

high

correlation

with

the

immature

monophasic

pattern

is

still

observed

It

is

not

clear

whether

the

monophasic

pattern

is

a

risk

factor

for

or

the

consequence

of

UTI

However

the

association

of

the

monophasic

jet

waveform

with

VUR

and

UTI

might

partially

explain

why

pregnant

women

with

a

higher

incidence

of

the

monophasic

jet

pattern

are

also

more

prone

to

VUR

and

UTI

-LSB-

-RSB-

A

higher

incidence

of

the

immature

jet

pattern

is

also

found

in

children

with

nocturnal

enuresis

-LSB-

-RSB-

This

suggests

that

there

is

a

lower

level

of

maturity

of

the

VUJ

in

a

proportion

of

enuretic

children

This

group

of

children

also

has

more

deranged

parameters

on

urodynamic

studies

The

hypothesis

of

dual

components

in

the

sphincteric

action

of

the

VUJ

might

also

help

explain

some

of

the

jet

phenomena

that

we

have

described

previously

The

multispike

pattern

in

the

ureteric

jet

resulting

from

pulsations

transmitted

from

adjacent

arteries

could

probably

be

explained

by

premature

relaxation

of

the

VUJ

that

precedes

the

ureteric

jet

proper

so

that

the

transmitted

arterial

pulse

becomes

dominant

Premature

relaxation

of

the

VUJ

is

also

likely

to

be

governed

by

the

neural

mechanism

seen

in

forced

diuresis

The

modification

involving

breaks

in

the

jet

is

predominantly

observed

when

the

bladder

is

maximally

full

Under

these

circumstances

the

intravesical

pressure

would

be

very

high

which

might

impose

a

countering

effect

on

the

pressure

wave

of

the

ureteric

jet

emitted

from

the

VUJ

Breaks

might

therefore

appear

within

the

jet

waveform

when

the

jet

velocity

drops

significantly

to

zero

flow

on

entering

the

bladder

In

summary

based

on

all

the

above

observations

we

postulate

that

the

human

VUJ

can

act

as

a

functional

sphincter

with

two

possible

components

-LRB-

-RRB-

a

myogenic

component

which

has

a

simple

open

and

close

action

that

gives

rise

to

the

monophasic

jet

pattern

and

-LRB-

-RRB-

a

neural

component

that

modulates

the

monophasic

waveform

into

a

more

complex

pattern

Further

anatomical

study

to

determine

the

exact

nature

of

the

sphincteric

muscle

governing

VUJ

function

is

warranted

The

major

implication

of

this

overview

of

ureteric

jet

patterns

is

a

change

of

concept

for

the

human

VUJ

Rather

than

being

a

passive

valve

the

VUJ

functions

as

an

active

sphincter

This

might

lead

to

a

novel

approach

to

the

management

of

VUR

UTI

and

enuresis

in

children

which

could

replace

traditional

treatment

Conclusion

This

review

has

provided

a

comprehensive

understanding

of

the

physiological

pattern

of

ureteric

jets

and

contributes

to

our

knowledge

of

the

pathophysiology

of

urinary

dysfunction

in

disease

entities

such

as

UTI

VUR

and

primary

enuresis

The

application

of

this

technique

in

future

studies

might

lead

to

novel

approaches

to

the

monitoring

and

prognosis

of

these

conditions

and

more

evidence-based

treatment

of

related

diseases

B O O O B I O O O O O O O O O O O O O O B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O B O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O B O O O O O O O O O O O O O B I O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

ureteric jet
vesicoureteric junction
doppler
children