Pediatric Janice
L. Marshall,
DMU
Vesicoureteric with Color Work
Neil
#{149}
D. Johnson,
FRACR
Margaret
P. De Campo,
#{149}
Reflux in Children: Doppler Imaging
Radiology
FRACR
Prediction
in Progress’
Unlike gray-scale sonography, color Doppler ultrasonography allows reliable visualization of the ureteric jet phenomenon. A study was undertaken to determine whether any measurable parameter predicts the presence of vesicoureteric reflux. Measurements of mean urine jet yelocity, longitudinal angle, transverse angle, and distance of the ongin of the jet from the midline of the bladder were obtained on 31 infants and children (62 unetens) with a proved urinary tract infection. Of these measurements, only the distance of the uretenic orifice from the midline of the bladder was found to correlate with vesicoureteric reflux (mean distance in the reflux group, 10.25 mm ± 2.40 (standard deviation [SD]); in the nonreflux group, 7.98 mm ± 2.40 [P .004]). The authors conclude that the more laterally positioned the uretenic orifice, the more likely it is to reflux. Color Doppler ultrasound measurement of the laterality of the uretenic orifice may be useful for predicting which children with a urinary tract infection would benefit from voiding cystourethrography.
V
reflux is demonstrated in approximately 30% of children with a first episode of unnary tract infection (1). Renal scarring may occur in a small proportion of these patients, and eventual renal impairment and hypertension are serious but uncommon end points (2,3). The detection and treatment of vesicouretenic reflux are, therefore, important. We currently investigate the first proved urinary tract infection with renal and bladder ultrasonography (US) followed by voiding cystounethrography (VCU). VCU is invasive and unpleasant and involves the use of ionizing radiation. Unsuccessful attempts have been made to replace VCU with less invasive tests. Color Doppler US allows the visualization of the uretenic jet as it enters the bladder. This study was undertaken to determine whether any measurements of the ureteric jet would predict the identification of vesicouretenic reflux during subsequent VCU. ESICOURETERIC
PATIENTS
AND
Color
Doppler
US depiction
of
method a lateral
of (re-
the uretenic jet demonstrating measurement of the MOD fluxing) orifice.
and
without
any
previous
for
knowledge
of the
nadiologic
results
of
studies.
Equipment The US examinations were obtained with a colon Doppler neal-time machine (model 128; Acuson, Mountain View, Calif). Both 5-MHz linear (model L538) and
METHODS
1.
Figure
3-MHz
Doppler
sector
(model
transducers
5328)
were
color
used.
Patients Index
terms:
Bladder,
Bladder,
US
studies,
genitourinary
839.12984
system,
system,
US
urinary
system,
ter,
abnormalities,
reflux,
studies,
#{149} Genitouninary
825.12984
825.85
Infants,
#{149} Ureter,
genito-
#{149}
Ureter,
82.1392
#{149}
US
male
ranging
#{149} Children,
825.85
825.85
Eight
83.85.
Ure-
#{149}
studies,
tract
known
Radiology
1990;
175:355-358
infection. on subsequently
ing
duplex
The
collecting
From
gust
the
31,
1989;
vision
received
vember
27.
0
Department
Hospital, 3052, Victoria,
RSNA,
of Radiology, Flemington Australia.
revision Address 1990
reprint
Royal
Rd. MelReceived
requested
November
to 9 years,
Patients with demonstrated
October
20;
accepted
requests
Au3; re-
to J.L.M.
were
well
a
were
was (4).
modenately
VCU
was
US
in
each
the
results
were
obtained
full
and when
but
perfonmed
at the
measurethe
not
ex-
patients
hydrated
of the examination,
ments
No-
system),
the study, as were of 10 years.
patients
time I
US
patients,
26 days
urinary abnormality, such as neuropathic bladder, previous urinary tract surgery, on a urinary tract malformation (includcluded from over the age
Children’s bourne
23 female
from
were examined, and measurements of the urine jets were recorded. The patients were all referred routinely for renal US and VCU after clinical diagnosis of un-
nary
825.12984
and
in age
Measurements
The bladder was examined in tnansverse and longitudinal planes with the patient supine, and the entire study was recorded on videotape. The following measurements were recorded on film and on the data sheet: bladder dimensions (anteropostenior, longitudinal, and transverse), distance of the origin of the jet from the midline (Fig 1), angle of the jet from the vertical in images obtained in transverse and longitudinal planes, and maximum mean velocity of the uretenic jet. To obtain the midline-to-orifice distance (MOD) measurement, a neproduc-
bladder
at capacity
within
case.
US
was
performed
were
recorded
before
24 hours and
VCU
of
Abbreviations: tance, VCU
ROC =
voiding
MOD =
receiver
=
midline-to-orifice
operating
dis-
characteristic,
cystourethrography.
Radiology
355
#{149}
70
60
$
50
#{149} #{149}
40
I.
n ‘,
0
#{149}
0 0
S.
40 8 I.
:
30’
LONGITUDINAL
E F ?
0
fs
S
ANGLE (Dree)
TRANSVERSE
§
S
ANGLE
#{149}
-10
00
(Ds.s)
S
-10
S. #{149}
S
-20
-20
0
S
$
-30
-30 N=
-40
-40
62
p-0.14
5
N=60 -50
p
=
-50 0.67 -60
NON
-
REFLUX
REFLUX
NON
REFLUX
-
REFLUX
-70
a.
b.
.5
20.
19
:
.4
N62
18
p0.50
17 16
p0.004
15 D I S 1 A N
S
0 S
.3
5
0
55
:
MEAN VELOCITY M.S.c1
14 13
0
12
0000
p
C E
S
0
...
10
00
#{149}..........
000
S
(mm)
55
.2
S...
0 0
55 55
.5
8
0
........
7
00
55
0
0
.5#{149}#{149}
5#{149}5 .5..
U,
.
0
S 55 555.55
0
S..
00 0 0 0 0
.1 S 5.
5
0
S.
A
. .
3
S
S..
.05
I,
I
I
NON-REFLUX
REFLUX
I
NON-REFLUX
REFLUX
d.
C.
Figure 2. Distribution sents one observation.
measured
i8.41 0; jfl the neflux
20.67#{176}. (b) Transverse jet angle. In the rtonreflux group, mean angle = 19.24#{176} ± 25.13#{176};in Jet velocity. In the nonreflux group, mean velocity 0.18 m/sec’ ± 0.087; in the reflux
group, 356
of observations of the four Values are means ± standard the reflux group, mean angle 15.86#{176} ± group, mean angle = 29.13#{176} ± 13.22#{176}. (c)
0.i63 .
m/sec’’
Radiology
± 0.073.
(d) MOD.
In the
parameters
deviations.
nonreflux
group,
versus
(a) Longitudinal
mean
distance
of vesicoureteric
presence jet angle.
7.98
mm
In the
± 2.67;
nonreflux
in the
reflux. group,
reflux
One dot or circle repremean
group,
angle
iO.25
18.37#{176}±
mm
2.40.
May
1990
US depicts ureteric jets more frequently and more reliably than realtime US alone. In our selected subjects, color Doppler US allowed ob-
1.00
S
0,
0.80
0 0.
servation S
Figure
3. ROC curve for the MOD measurement.
0.60
of the
of both the the patients portant
0.40
ureteric
patients without
that
the
in
100%
bladder
not
be over-
exami-
filled
>
nation and that the patient be well hydrated (7). The reliability of observation of the ureteric jet allowed us to search for measurements of the jet that might correlate with the presence of vesicoureteric reflux. The maximum
0.20
C,)
z
w 0.00
Cl)
1.0 1
(false positive)
SPECIFiCITY
-
mean ible midline point in the bladder termined by first measuring the
verse
bladder
dimension
was trans-
de-
gles,
(at the level
of
the posterior bladder wall). The midpoint of the bladder was then determined by placing a cursor at half the measured transverse
point this
bladder
of origin defined
midline
and recorded. dune
was
uretenic
distance
of the
was
This
performed
(Fig
ureteric then
procefor each
jet.
The angle between the ureteric jet and vertical was measured in both transverse and longitudinal imaging planes with the use of electronic calipers. The maximum mean velocity of the jet the
was measured
by placing
the velocity
cal-
iper on the part of the jet that showed maximum velocity on the color Doppler image. The caliper was then moved within the area of maximum velocity until the maximum angle-corrected reading was obtained.
VCU
Technique
A standard
VCU technique
was used
for all patients. After sterile catheterizalion of the bladder with either a 5-F or an 8-F catheter, the bladder was filled by means of gravity to a pressure of 1 m
H2O, and radiognaphs the patient tions. The oroscopy
and
a spot
were
obtained
spontaneous
radiograph
voiding,
of the
pelvis at the end of voiding was obtained. Any reflux was recorded on films, so that the grade of refiux could be determined with use of the international grading system (5). A radiograph of the renal areas was obtamed less than 60 seconds after the cessation of voiding.
RESULTS Of the 62 ureters studied, refiux was demonstrated at VCU in 16. Reflux occurred on one side in six patients and on both sides in five patients. The data were analyzed with the Student rameter.
t test for each For mean jet
Volume
175
Number
#{149}
measured velocity
2
t test
paand
showed
jet an-
no correlation
between
the
tially
means,
there is still a degree of overlap in the observations. This is tolerable for a proposed “case-finding” test. We did not attempt to stratify the measurements by patient age, as there were insufficient numbers in each group. Figure 2 shows the relationship between the presence or absence of yesicouretenic
sured angle, locity, The
reflux
and
US parameters longitudinal and MOD).
the
four
jet velocity and jet angles meain transverse and longitudinal showed no correlation with The MOD was the only poten-
sured planes reflux.
of the reflux and nonreflux (P = .004). Even though there
mea-
(transverse jet jet angle, jet ye-
useful measurement (Fig 2d). Stephens (10) has shown that a ureter with a laterally placed ureteric orifice seen at cystoscopy is more likely to be affected by reflux than a ureter with a more medial orifice. Assuming that the point of origin of the ureteric jet seen at US correlates with the actual position of the ureteric onfice, our results support the findings of Stephens. The of the
difference
between
the means
measurements for refluxing nonrefluxing ureters was significant (P .004). If the MOD is to be used as a case-finding test, the number of false-negative results
must
MOD and
be very
low.
The
cutoff
point
curve (ROC) for the MOD is presented in Figure 3. This is a plot comparing true-positive findings (sensitivity) versus false-positive findings (1
for the test must therefore be chosen to minimize false-negative findings. The ROC curve for orifice distance (Fig 3) indicates that this cutoff point is somewhere between 7 and 9 mm.
specificity).
The
receiver
operating
-
small
number
of observations
in
this
preliminary study, however, does not allow us to choose a final cutoff point with any certainty. If a distance of 7 mm or less is chosen as the cutoff point, two of 21 refluxing ureters would have been misdiagnosed (false-negative). These
DISCUSSION
with
in night and left oblique posipatient was observed with fluduring
the
transverse
is discrimination
measured
separately
and
between the measurements and reflux (Fig 2a-2c). For the MOD, there was a significant difference in the
means groups
1). The
jet from
measurement
longitudinal
beginning
of the
II-
at the
jet
with reflux and reflux. It is im-
The distal
expulsion ureter
of urine into
in a jet of urine bladder. Jetting during
the
being has
intravenous
from
the
bladder
results
formed in the been observed urography
(6,7)
and cystoscopy. teral jets were
In one study (8), ureseen in 32% of ureters during an intravenous urographic examination; in that study, the authors concluded that the finding of a ureteric jet at intravenous urography was strongly associated with absence of vesicoureteric reflux. The ureteric jet is sometimes seen as a hyperechoic jet during routine real-time US of the bladder. Kremer et a! (9) observed ureteric jets in 60% of 264 unselected
patients
physical
basis
these
and
investigated
the
for US visualization
jets.
We have
shown
that
color
Doppler
of
two ureters were in a single male patient who was subsequently shown to have bilateral grade 2 reflu.x. If a distance of 8 mm on less is chosen, the examinations of three of 30 refluxing ureters would have been false-negative. The additional ureter was subsequently shown to have
grade
3 reflux.
For clinical data, we look sensitivity and specificity of and express its significance dividual patient through its predictive value or negative tive value. Since we are most ested in predicting whether
at the a test for an inpositive predicintera patient
with
is unlike-
any
given
MOD
value
Radiology
#{149} 357
ly to experience reflu.x, the relevant value is the negative predictive value. For an MOD value of 7 mm or less, the negative predictive value in this study was 0.87. We now plan to apply the MOD measurement to a larger patient group in order to confirm the validity of the correlation and to enable a more informed decision concerning the cutoff level. In considering the accuracy of the
MOD
for predicting
the presence
or
absence of reflux, it should be remembered that the standard of reference for this comparison, the VCU examination, is known to be flawed. In summary, the development of color Doppler US has allowed reliable visualization of the uretenic jet phenomenon in the bladder. Using the point of origin of the ureteric jet
as an estimate of the position of the uretenc orifice in the bladder, we have shown a significant correlation between
the
laterality
presence
358
of a ureteric
Radiology
#{149}
orifice
and
and the
jet does
reflux. for jet yethis study has US
visualiza-
not
exclude
reflux.
On
the
basis
of
these preliminary findings, a larger study is proposed to validate the use of the MOD as a predictor of the ab-
sence
of vesicoureteric
establish
a more
reflux
accurate
if the study
3.
Wallace DMA, Rothwell DL, Williams DI. The long term follow-up of surgically treated vesicouretenal neflux. Br J Unol 1978; 50:479-484.
4.
Dubbins
and
to of cut-
level
off. Further issues, such as the change in MOD with degrees of bladder filling and the normal range of MOD in various age groups, will also be addressed. It is suggested that findings of this preliminary are confirmed by those of the
larger study, the MOD could be used to determine which patients with a first urinary tract infection should undergo VCU.
PA,
Acknowledgments: We thank FRACS, and F. Douglas Stephens, sultant urologists), for numerous cussions on vesicouretenic reflux
Radiology
5.
6.
7.
Ian, FRACP, on statistical
PhD, for most valuable matters.
FRACS
2.
McKerrew
W, Davidson-Lamb
J, Goldberg
1981;
140:513-515.
Refiux Study Committee 1981. Medical versus surgical treatment of primary vesicoureteral reflux: a pro-
spective international reflux study in children. J Unol 1981; 125:277-283. Kalmon EH, Albers DD, Dunn JH. Ureteral jet phenomenon: stream of opaque medium simulating an anomalous configuration of the ureter. Radiology 1955; 65:933-935. Kjellberg SR. Ericsson NO, Rudhe U. The lower urinary tract in childhood: some clinical Chicago:
and
roentgenological Year
Book
Medical,
1957; 182-202. (con-
8.
dis-
and Terry Noguidance
9.
References 1.
AB, Derby
International
correlated
R. Fowler, helpful
Kurtz
BB. Ureteric jet effect: the echognaphic appearance of urine entering the bladder.
observations.
of vesicoureteric was found
No correlation locity or jet angle, clearly shown that
tion
of the
vesicoureteric
N, Jones
PF. Urinary tract infection in children. Br Med J 1984; 289:299-303. Smellie J, Edwards D, Hunter N, Normand ICS, Prescod N. Vesico-uretenic reflux and renal scarring. Kidney Int 1975; 8:S65-S72.
10.
Kuhns
LR, Hennandez
R, Koff
S. Thorn-
bury JR, Poznanski AK, Holt JF. Absence of vesicouretenal reflux in children with ureteral jets. Radiology 1977; 124:185-187. Kremer H, Dobninski W, Mikyska M, Baumgartner M, Zollmer N. Ultrasonic in vivo and in vitro studies on the nature of the ureteral jet phenomenon. Radiology 1982; 142:175-177. Stephens FD. Cystoscopic appearances of the ureteric orifices associated with reflux nephropathy. In: Hodson J, Kincaid-Smith P, eds. Reflux nephropathy. New York: Masson, 1979; 119-125.
May
1990
L. Marshall,
DMU
Vesicoureteric with Color Work
Neil
#{149}
D. Johnson,
FRACR
Margaret
P. De Campo,
#{149}
Reflux in Children: Doppler Imaging
Radiology
FRACR
Prediction
in Progress’
Unlike gray-scale sonography, color Doppler ultrasonography allows reliable visualization of the ureteric jet phenomenon. A study was undertaken to determine whether any measurable parameter predicts the presence of vesicoureteric reflux. Measurements of mean urine jet yelocity, longitudinal angle, transverse angle, and distance of the ongin of the jet from the midline of the bladder were obtained on 31 infants and children (62 unetens) with a proved urinary tract infection. Of these measurements, only the distance of the uretenic orifice from the midline of the bladder was found to correlate with vesicoureteric reflux (mean distance in the reflux group, 10.25 mm ± 2.40 (standard deviation [SD]); in the nonreflux group, 7.98 mm ± 2.40 [P .004]). The authors conclude that the more laterally positioned the uretenic orifice, the more likely it is to reflux. Color Doppler ultrasound measurement of the laterality of the uretenic orifice may be useful for predicting which children with a urinary tract infection would benefit from voiding cystourethrography.
V
reflux is demonstrated in approximately 30% of children with a first episode of unnary tract infection (1). Renal scarring may occur in a small proportion of these patients, and eventual renal impairment and hypertension are serious but uncommon end points (2,3). The detection and treatment of vesicouretenic reflux are, therefore, important. We currently investigate the first proved urinary tract infection with renal and bladder ultrasonography (US) followed by voiding cystounethrography (VCU). VCU is invasive and unpleasant and involves the use of ionizing radiation. Unsuccessful attempts have been made to replace VCU with less invasive tests. Color Doppler US allows the visualization of the uretenic jet as it enters the bladder. This study was undertaken to determine whether any measurements of the ureteric jet would predict the identification of vesicouretenic reflux during subsequent VCU. ESICOURETERIC
PATIENTS
AND
Color
Doppler
US depiction
of
method a lateral
of (re-
the uretenic jet demonstrating measurement of the MOD fluxing) orifice.
and
without
any
previous
for
knowledge
of the
nadiologic
results
of
studies.
Equipment The US examinations were obtained with a colon Doppler neal-time machine (model 128; Acuson, Mountain View, Calif). Both 5-MHz linear (model L538) and
METHODS
1.
Figure
3-MHz
Doppler
sector
(model
transducers
5328)
were
color
used.
Patients Index
terms:
Bladder,
Bladder,
US
studies,
genitourinary
839.12984
system,
system,
US
urinary
system,
ter,
abnormalities,
reflux,
studies,
#{149} Genitouninary
825.12984
825.85
Infants,
#{149} Ureter,
genito-
#{149}
Ureter,
82.1392
#{149}
US
male
ranging
#{149} Children,
825.85
825.85
Eight
83.85.
Ure-
#{149}
studies,
tract
known
Radiology
1990;
175:355-358
infection. on subsequently
ing
duplex
The
collecting
From
gust
the
31,
1989;
vision
received
vember
27.
0
Department
Hospital, 3052, Victoria,
RSNA,
of Radiology, Flemington Australia.
revision Address 1990
reprint
Royal
Rd. MelReceived
requested
November
to 9 years,
Patients with demonstrated
October
20;
accepted
requests
Au3; re-
to J.L.M.
were
well
a
were
was (4).
modenately
VCU
was
US
in
each
the
results
were
obtained
full
and when
but
perfonmed
at the
measurethe
not
ex-
patients
hydrated
of the examination,
ments
No-
system),
the study, as were of 10 years.
patients
time I
US
patients,
26 days
urinary abnormality, such as neuropathic bladder, previous urinary tract surgery, on a urinary tract malformation (includcluded from over the age
Children’s bourne
23 female
from
were examined, and measurements of the urine jets were recorded. The patients were all referred routinely for renal US and VCU after clinical diagnosis of un-
nary
825.12984
and
in age
Measurements
The bladder was examined in tnansverse and longitudinal planes with the patient supine, and the entire study was recorded on videotape. The following measurements were recorded on film and on the data sheet: bladder dimensions (anteropostenior, longitudinal, and transverse), distance of the origin of the jet from the midline (Fig 1), angle of the jet from the vertical in images obtained in transverse and longitudinal planes, and maximum mean velocity of the uretenic jet. To obtain the midline-to-orifice distance (MOD) measurement, a neproduc-
bladder
at capacity
within
case.
US
was
performed
were
recorded
before
24 hours and
VCU
of
Abbreviations: tance, VCU
ROC =
voiding
MOD =
receiver
=
midline-to-orifice
operating
dis-
characteristic,
cystourethrography.
Radiology
355
#{149}
70
60
$
50
#{149} #{149}
40
I.
n ‘,
0
#{149}
0 0
S.
40 8 I.
:
30’
LONGITUDINAL
E F ?
0
fs
S
ANGLE (Dree)
TRANSVERSE
§
S
ANGLE
#{149}
-10
00
(Ds.s)
S
-10
S. #{149}
S
-20
-20
0
S
$
-30
-30 N=
-40
-40
62
p-0.14
5
N=60 -50
p
=
-50 0.67 -60
NON
-
REFLUX
REFLUX
NON
REFLUX
-
REFLUX
-70
a.
b.
.5
20.
19
:
.4
N62
18
p0.50
17 16
p0.004
15 D I S 1 A N
S
0 S
.3
5
0
55
:
MEAN VELOCITY M.S.c1
14 13
0
12
0000
p
C E
S
0
...
10
00
#{149}..........
000
S
(mm)
55
.2
S...
0 0
55 55
.5
8
0
........
7
00
55
0
0
.5#{149}#{149}
5#{149}5 .5..
U,
.
0
S 55 555.55
0
S..
00 0 0 0 0
.1 S 5.
5
0
S.
A
. .
3
S
S..
.05
I,
I
I
NON-REFLUX
REFLUX
I
NON-REFLUX
REFLUX
d.
C.
Figure 2. Distribution sents one observation.
measured
i8.41 0; jfl the neflux
20.67#{176}. (b) Transverse jet angle. In the rtonreflux group, mean angle = 19.24#{176} ± 25.13#{176};in Jet velocity. In the nonreflux group, mean velocity 0.18 m/sec’ ± 0.087; in the reflux
group, 356
of observations of the four Values are means ± standard the reflux group, mean angle 15.86#{176} ± group, mean angle = 29.13#{176} ± 13.22#{176}. (c)
0.i63 .
m/sec’’
Radiology
± 0.073.
(d) MOD.
In the
parameters
deviations.
nonreflux
group,
versus
(a) Longitudinal
mean
distance
of vesicoureteric
presence jet angle.
7.98
mm
In the
± 2.67;
nonreflux
in the
reflux. group,
reflux
One dot or circle repremean
group,
angle
iO.25
18.37#{176}±
mm
2.40.
May
1990
US depicts ureteric jets more frequently and more reliably than realtime US alone. In our selected subjects, color Doppler US allowed ob-
1.00
S
0,
0.80
0 0.
servation S
Figure
3. ROC curve for the MOD measurement.
0.60
of the
of both the the patients portant
0.40
ureteric
patients without
that
the
in
100%
bladder
not
be over-
exami-
filled
>
nation and that the patient be well hydrated (7). The reliability of observation of the ureteric jet allowed us to search for measurements of the jet that might correlate with the presence of vesicoureteric reflux. The maximum
0.20
C,)
z
w 0.00
Cl)
1.0 1
(false positive)
SPECIFiCITY
-
mean ible midline point in the bladder termined by first measuring the
verse
bladder
dimension
was trans-
de-
gles,
(at the level
of
the posterior bladder wall). The midpoint of the bladder was then determined by placing a cursor at half the measured transverse
point this
bladder
of origin defined
midline
and recorded. dune
was
uretenic
distance
of the
was
This
performed
(Fig
ureteric then
procefor each
jet.
The angle between the ureteric jet and vertical was measured in both transverse and longitudinal imaging planes with the use of electronic calipers. The maximum mean velocity of the jet the
was measured
by placing
the velocity
cal-
iper on the part of the jet that showed maximum velocity on the color Doppler image. The caliper was then moved within the area of maximum velocity until the maximum angle-corrected reading was obtained.
VCU
Technique
A standard
VCU technique
was used
for all patients. After sterile catheterizalion of the bladder with either a 5-F or an 8-F catheter, the bladder was filled by means of gravity to a pressure of 1 m
H2O, and radiognaphs the patient tions. The oroscopy
and
a spot
were
obtained
spontaneous
radiograph
voiding,
of the
pelvis at the end of voiding was obtained. Any reflux was recorded on films, so that the grade of refiux could be determined with use of the international grading system (5). A radiograph of the renal areas was obtamed less than 60 seconds after the cessation of voiding.
RESULTS Of the 62 ureters studied, refiux was demonstrated at VCU in 16. Reflux occurred on one side in six patients and on both sides in five patients. The data were analyzed with the Student rameter.
t test for each For mean jet
Volume
175
Number
#{149}
measured velocity
2
t test
paand
showed
jet an-
no correlation
between
the
tially
means,
there is still a degree of overlap in the observations. This is tolerable for a proposed “case-finding” test. We did not attempt to stratify the measurements by patient age, as there were insufficient numbers in each group. Figure 2 shows the relationship between the presence or absence of yesicouretenic
sured angle, locity, The
reflux
and
US parameters longitudinal and MOD).
the
four
jet velocity and jet angles meain transverse and longitudinal showed no correlation with The MOD was the only poten-
sured planes reflux.
of the reflux and nonreflux (P = .004). Even though there
mea-
(transverse jet jet angle, jet ye-
useful measurement (Fig 2d). Stephens (10) has shown that a ureter with a laterally placed ureteric orifice seen at cystoscopy is more likely to be affected by reflux than a ureter with a more medial orifice. Assuming that the point of origin of the ureteric jet seen at US correlates with the actual position of the ureteric onfice, our results support the findings of Stephens. The of the
difference
between
the means
measurements for refluxing nonrefluxing ureters was significant (P .004). If the MOD is to be used as a case-finding test, the number of false-negative results
must
MOD and
be very
low.
The
cutoff
point
curve (ROC) for the MOD is presented in Figure 3. This is a plot comparing true-positive findings (sensitivity) versus false-positive findings (1
for the test must therefore be chosen to minimize false-negative findings. The ROC curve for orifice distance (Fig 3) indicates that this cutoff point is somewhere between 7 and 9 mm.
specificity).
The
receiver
operating
-
small
number
of observations
in
this
preliminary study, however, does not allow us to choose a final cutoff point with any certainty. If a distance of 7 mm or less is chosen as the cutoff point, two of 21 refluxing ureters would have been misdiagnosed (false-negative). These
DISCUSSION
with
in night and left oblique posipatient was observed with fluduring
the
transverse
is discrimination
measured
separately
and
between the measurements and reflux (Fig 2a-2c). For the MOD, there was a significant difference in the
means groups
1). The
jet from
measurement
longitudinal
beginning
of the
II-
at the
jet
with reflux and reflux. It is im-
The distal
expulsion ureter
of urine into
in a jet of urine bladder. Jetting during
the
being has
intravenous
from
the
bladder
results
formed in the been observed urography
(6,7)
and cystoscopy. teral jets were
In one study (8), ureseen in 32% of ureters during an intravenous urographic examination; in that study, the authors concluded that the finding of a ureteric jet at intravenous urography was strongly associated with absence of vesicoureteric reflux. The ureteric jet is sometimes seen as a hyperechoic jet during routine real-time US of the bladder. Kremer et a! (9) observed ureteric jets in 60% of 264 unselected
patients
physical
basis
these
and
investigated
the
for US visualization
jets.
We have
shown
that
color
Doppler
of
two ureters were in a single male patient who was subsequently shown to have bilateral grade 2 reflu.x. If a distance of 8 mm on less is chosen, the examinations of three of 30 refluxing ureters would have been false-negative. The additional ureter was subsequently shown to have
grade
3 reflux.
For clinical data, we look sensitivity and specificity of and express its significance dividual patient through its predictive value or negative tive value. Since we are most ested in predicting whether
at the a test for an inpositive predicintera patient
with
is unlike-
any
given
MOD
value
Radiology
#{149} 357
ly to experience reflu.x, the relevant value is the negative predictive value. For an MOD value of 7 mm or less, the negative predictive value in this study was 0.87. We now plan to apply the MOD measurement to a larger patient group in order to confirm the validity of the correlation and to enable a more informed decision concerning the cutoff level. In considering the accuracy of the
MOD
for predicting
the presence
or
absence of reflux, it should be remembered that the standard of reference for this comparison, the VCU examination, is known to be flawed. In summary, the development of color Doppler US has allowed reliable visualization of the uretenic jet phenomenon in the bladder. Using the point of origin of the ureteric jet
as an estimate of the position of the uretenc orifice in the bladder, we have shown a significant correlation between
the
laterality
presence
358
of a ureteric
Radiology
#{149}
orifice
and
and the
jet does
reflux. for jet yethis study has US
visualiza-
not
exclude
reflux.
On
the
basis
of
these preliminary findings, a larger study is proposed to validate the use of the MOD as a predictor of the ab-
sence
of vesicoureteric
establish
a more
reflux
accurate
if the study
3.
Wallace DMA, Rothwell DL, Williams DI. The long term follow-up of surgically treated vesicouretenal neflux. Br J Unol 1978; 50:479-484.
4.
Dubbins
and
to of cut-
level
off. Further issues, such as the change in MOD with degrees of bladder filling and the normal range of MOD in various age groups, will also be addressed. It is suggested that findings of this preliminary are confirmed by those of the
larger study, the MOD could be used to determine which patients with a first urinary tract infection should undergo VCU.
PA,
Acknowledgments: We thank FRACS, and F. Douglas Stephens, sultant urologists), for numerous cussions on vesicouretenic reflux
Radiology
5.
6.
7.
Ian, FRACP, on statistical
PhD, for most valuable matters.
FRACS
2.
McKerrew
W, Davidson-Lamb
J, Goldberg
1981;
140:513-515.
Refiux Study Committee 1981. Medical versus surgical treatment of primary vesicoureteral reflux: a pro-
spective international reflux study in children. J Unol 1981; 125:277-283. Kalmon EH, Albers DD, Dunn JH. Ureteral jet phenomenon: stream of opaque medium simulating an anomalous configuration of the ureter. Radiology 1955; 65:933-935. Kjellberg SR. Ericsson NO, Rudhe U. The lower urinary tract in childhood: some clinical Chicago:
and
roentgenological Year
Book
Medical,
1957; 182-202. (con-
8.
dis-
and Terry Noguidance
9.
References 1.
AB, Derby
International
correlated
R. Fowler, helpful
Kurtz
BB. Ureteric jet effect: the echognaphic appearance of urine entering the bladder.
observations.
of vesicoureteric was found
No correlation locity or jet angle, clearly shown that
tion
of the
vesicoureteric
N, Jones
PF. Urinary tract infection in children. Br Med J 1984; 289:299-303. Smellie J, Edwards D, Hunter N, Normand ICS, Prescod N. Vesico-uretenic reflux and renal scarring. Kidney Int 1975; 8:S65-S72.
10.
Kuhns
LR, Hennandez
R, Koff
S. Thorn-
bury JR, Poznanski AK, Holt JF. Absence of vesicouretenal reflux in children with ureteral jets. Radiology 1977; 124:185-187. Kremer H, Dobninski W, Mikyska M, Baumgartner M, Zollmer N. Ultrasonic in vivo and in vitro studies on the nature of the ureteral jet phenomenon. Radiology 1982; 142:175-177. Stephens FD. Cystoscopic appearances of the ureteric orifices associated with reflux nephropathy. In: Hodson J, Kincaid-Smith P, eds. Reflux nephropathy. New York: Masson, 1979; 119-125.
May
1990
