Use of urographic contrast media to determine glomerular filtration rate. Determining the glomerular filtration rate of each kidney with computed tomography and scintigraphy


Almén, T.; Bergquist, D.; Frennby, B.; Hellsten, S.; Lilja, B.; Nyman, U.; Sterner, G.; Törnquist, C.

Investigative Radiology 26 Suppl 1: S72-4; Discussion S88-91

1991


CT examination with iohexol (or other iodine contrast media with the same pharmakokinetics as iohexol) as marker of GFR can be used to determine the relative GFR of the two kidneys. The advantages are ability to determine GFR of each kidney at all places were a CT machine is available and the ability to get both morphology (CT images) and function (GFR determination) on one occasion and following one contrast medium injection.

Iodinated
Agents—Pharmacokinetics
and
Renal
Function
Use
of
Urographic
Contrast
Media
to
Determine
Glomerular
Filtration
Rate
Determining
the
Glomerular
Filtration
Rate
of
Each
Kidney
with
Computed
Tomography
and
Scintigraphy
TORSTEN
ALMEN,
MD,*
DAVID
BERGQUIST,
MD,t
BO
FRENNBY,
MD,*
SVERKER
HELLSTEN,
MD,t
BO
LILJA,
MD,§
ULF
NYMAN,
MD,*
GUNNAR
STERNER,
MD,11
AND
CARL
TORNQUIST,
MD*
Almen
T,
Bergquist
D,
Frennby
B,
Helisten
S,
Lilja
B,
Nyman
U,
Sterner
G,
Thrnquist
C.
Use
of
urographic
contrast
media
to
determine
glomerular
filtration
rate:
determining
the
glo-
merular
filtration
rate
of
each
kidney
with
computed
tomog-
raphy
and
scintigraphy.
Invest
Radiol
1991;26:S72—S74.
A
SUBSTANCE
MAY
be
used
as
marker
of
glomerular
fil-
tration
rate
(GFR)
if
1.)
it
is
eliminated
from
the
body
by
glomerular
filtration
and
2.)
it
has
no
major
excretion
or
reabsorbtion
via
the
renal
tubules.
Examples
of
such
sub-
stances
are
inulin,
51
Cr-EDTA,
99
mTc-DTPA,
Gd-DTPA,
ionic
and
non-ionic
contrast
media
for
urography.
The
total
GFR
of
the
two
kidneys
can
with
any
GFR-marker
be
de-
termined
as
total
plasma
clearance
of
the
marker
or
as
renal
plasma
clearance
of
the
marker
following
one
or
several
intravenous
bolus
injections
of
the
marker.
You
might
want
to
know
both
morphology
and
function
(as
GFR)
of
the
kidneys.
The
morphology
may
be
revealed
with,
for
instance,
urography
and
computed
tomography
following
intravascular
injection
of
urographic
contrast
me-
dia.
The
GFR
of
the
individual
kidney,
expressed
as
per-
centage
of
total
GFR,
may
be
determined
with
scintigraphy
following
intravenous
injection
of
for
instance
99
mTc-
DTPA.
Total
GFR
may
be
determined
as
total
plasma
clear-
ance
or
renal
plasma
clearance
of
urographic
contrast
me-
dia,
51
Cr-EDTA
or
99m
Tc-DTPA.
From
the
*Departments
of
Diagnostic
Radiology,
tVascular
Surgery,
Wrology,
§Clinical
Physiology
(Nuclear
Medicine),
and
11Nephrology,
Malmo
General
Hospital,
Malmo,
Sweden.
Today
determination
of
GFR
of
each
kidney
is
made
by
gamma
camera
(dynamic
imaging).
The
amount
of
the
GFR
marker
99m
Tc-DTPA
accumulated
in
a
kidney
at
2
minutes
after
intravascular
injection
is
directly
proportional
to
the
GFR
of
that
kidney
and
is
determined.
We
suggest
that,
in
a
similar
way,
determination
of
GFR
of
each
kidney
could
be
made
by
CT
machine
(dynamic
computed
tomography).
The
accumulation
in
each
kidney
of
the
GFR
marker
iohexol
is
determined
in
multiple
CT
slices
made
through
the
volume
of
the
kidneys,
from
the
upper
to
the
lower
pole,
in
the
period
1
to
4
minutes
after
the
intravenous
iohexol
injection.
If
determination
of
GFR
could
be
made
with
computed
tomography
this
would
give
the
following
advantages:
1.
Determination
of
GFR
of
each
kidney
can
be
made
at
places
where
CT
machine
is
available
but
a
gamma
camera
is
not
available.
2.
You
will
get
both
renal
morphology
and
renal
func-
tion
after
one
contrast
medium
injection
at
one
diag-
nostic
occasion.
In
patients,
in
whom
you
want
to
investigate
both
mor-
phology
of
renal
region
and
the
GFR,
the
three
examina-
tions
CT
(1),
determination
of
relative
GFR
(2)
of
each
kidney
(as
described
above)
and
determination
of
absolute
value
of
total
GFR
(3)
(by
total
plasma
clearance
or
renal
clearance
of
GFR
marker)
can
be
made
after
one
injection
of
contrast
medium.
S72
Suppl.
1
UROGRAPHIC
CONTRAST
MEDIA
TO
DETERMINE
GFR
Almen,
et
al
S73
Materials
and
Methods
Materials
In
the
period
October
1990—May
1991
a
group
of
patients
with
renal
artery
stenosis,
aortic
aneurysm,
hydronephrosis,
pyelone-
phritis,
renal
stone
disease,
hematuria
were
referred
for
computed
tomography
(CT)
to
evaluate
anatomy
and
the
relation
between
the
GFR
of
the
two
kidneys.
Among
these
patients,
we
collected
all
those
who
agreed
with
the
following
two
requests:
1.
Determination
of
relative
GFR
of
each
kidney
had
been
per-
formed
with
both
gamma
camera
and
CT
machine
and;
2.
There
was
no
clinical
reason
to
assume
a
larger
change
in
renal
function
between
the
two
investigations.
The
group
collected
in
this
way
included
10
women
with
mean
age
47
years
(range
24-72
years)
and
10
men
with
mean
age
49
years
(range
23-68
years).
In
12
patients
the
delay
between
scin-
tigraphy
and
CT
examination
was
1-2
days;
in
5
patients
the
delay
was
3-21
days;
in
3
patients
1
to
4
months.
Methods
With
gamma
camera
(Toshiba)
(Department
of
nuclear
medi-
cine)
renal
scintigrams
were
obtained
2
minutes
after
bolus
injec-
tion
of
200
MBq
99
mTc-DTPA.
The
relation
between
the
amounts
of
the
GFR
marker
accumulated
in
the
two
kidneys
is
equal
to
the
relation
between
the
GFR
of
the
two
kidneys
and
was
noted.
With
CT
machine
(Siemens
Somatom
DR)
(Department
of
Di-
agnostic
Radiology)
10
CT-slices
with
8
mm
thickness
were
made
of
the
kidneys
in
the
period
1
to
4
minutes
after
bolus
injection
of
50
mL
iohexol
300
mg
I/mL.
The
relation
between
the
amounts
of
TABLE
1.
The
Glomerular
Filtration
Rate
(GFR)
of
an
Individual
Kidney
Expressed
as
a
Percentage
of
Total
GFR
Patient
Right
kidney
Left
kidney
CT
Scintigraphy
CT
Scintigraphy
1
55
56
45
44
2
18
19
82
81
3
52
53
48
47
4
11
14
89
86
5
43
45 57
55
6
50
46
50
54
7
35
37
65
63
8
45
41
55
59
9
58
60
42
40
10
57
58
43
42
11
40
40
60 60
12
48
44
52
56
13
53
58
47
42
14
49
46
51
54
15
45
42
55 58
16
26
25
74
75
17
49 49
51
51
18
20
24
80
76
19
44 44
56
56
20
66
67
34
33
CT:
computed
tomography.
Ichexol
03nruted
Tarcgraphy
100
%
50%
9911
1
-
t-DrPA
Scintigraphy
50%
100
%
Fig.
1.
The
fraction
of
total
glomerular
filtration
rate
(in
per-
cent)
produced
by
one
kidney
and
determined
with
computed
tomography
(CT)
with
iohexol
as
GFR-marker
and
scintigraphy
(gamma
camera)
with
99
mTc-DTPA
as
GFR-marker.
the
GFR
marker
iohexol
accumulated
in
the
two
kidneys
is
equal
to
the
relation
between
the
GFR
of
the
two
kidneys
and
was
noted.
The
CT-slices
were
evenly
distributed
in
the
body
volume
between
the
cranial
pole
of
the
most
cranially
situated
kidney
and
the
cau-
dal
pole
of
the
most
caudally
situated
kidney.
In
this
way
the
CT-slices
became
a
sample
of
kidney
volume
comprising
about
60%
of
the
total
volume
of
the
kidneys.
The
amount
of
iohexol
accumulated
in
a
kidney
was
regarded
as
an
"increased
attenua-
tion
capacity"
of
that
kidney
which
was
calculated
in
the
follow-
ing
way
(details
will
be
published
elsewhere):
After
contrast
medium
injection
"the
number
of
all
the
kidney
voxels
of
all
the
CT
slices
after
contrast
medium"
was
multiplied
by
"the
mean
Hounsfield
number
of
all
the
kidney
voxels
of
all
the
CT
slices
after
contrast
medium"
and
this
product
represents
the
attenuation
capacity
of
the
basic
parenchyma
of
that
kidney
plus
its
content
of
contrast
medium.
To
get
the
attenuation
capacity
of
the
accumulated
iohexol
alone
in
the
kidney
the
attenuation
capacity
of
the
basic
renal
parenchyma
must
be
subtracted
from
the
product
just
mentioned.
To
get
the
attenuation
capacity
of
the
renal
paren-
chyma
alone
after
contrast
medium
injection
(remember
that
the
kidney
increases
in
size
after
contrast
medium
injection!)
"the
mean
Hounsfield
number
of
the
kidney
voxels
before
contrast
medium
injection"
was
multiplied
by
"the
number
of
all
kidney
voxels
of
all
the
CT
slices
after
contrast
medium."
Results
The
results
are
given
in
the
table
and
in
the
figure.
In
all
20
patients
the
difference
in
relative
GFR measured
with
gamma
camera
or
CT
machine
was
5%
points
or
less;
in
19
patients
the
difference
was
4%
points
or
less;
in
9
patients
(approximately
half
the
material)
the
difference
was
1%
point
or
less.
Coefficient
of
correlation
of
the
two
methods
was
0.98.
S74
INVESTIGATIVE
RADIOLOGY
November
Supplement
1991
Vol.
26
Discussion
The
results
suggest
that
the
relation
between
the
GFR
of
the
two
kidneys
can
be
measured
as
accurately
with
CT
as
with
the
gamma
camera.
It
must
be
remembered
that
a
CT
investigation
with
15
abdominal
slices
gives
a
much
higher
radiation
dose
than
a
gamma
camera
investigation.
There-
fore
CT
determination
of
the
relative
GFR
of
the
two
kid-
neys
should
only
be
made
when
there
is
a
need
for
the
morphologic
content
of
the
CT
image,
otherwise
the
scin-
tigraphic
examination
should
be
performed.
Conclusion
CT
examination
with
iohexol
(or
other
iodine
contrast
media
with
the
same
pharmakokinetics
as
iohexol)
as
marker
of
GFR
can
be
used
to
determine
the
relative
GFR
of
the
two
kidneys.
The
advantages
are
ability
to
determine
GFR
of
each
kidney
at
all
places
were
a
CT
machine
is
available
and
the
ability
to
get
both
morphology
(CT
images)
and
function
(GFR
determination)
on
one
occasion
and
following
one
contrast
medium
injection.