Computed
Tomography Diagnosis
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JAMES
H. CHRISTIE,1
and Radionuclide Studies of Intracranial Disease
HIROFUMI AND
MORI, ROLF
RAYMUNDO L. SCHAPIRO
The accuracy of CT and radionuclide studies in the diagnosis of intracranial disease is analyzed based on experience in 641 patients. Results indicate that both modalities give reasonably similar precision and that a modest improve-
scanning
considered
in this
Computed
tomography
and
initially
achieved
procedures,
so that
this
(CT)
reported
introduced
by Ambrose
widespread
obtained
scans,
acclaim
by the
angiography,
CT is certain radiologic provides
in 1 973
in the
diagnosis
it appears comparable
combination
and
of
cranial
[1]
of
intra-
to provide in a to that previ-
radionuclide
as the screening
test for suspected
it in
in patients
in whom
to
clarify
studies intracranial
tenial
stereoscopic
earlier
who
findings
were strongly
used
(EMI)
is essentially
[3, 4]. Image enhancement initially
was
or
images to
were
confirm
suspected
used
sparingly
but
increased
Am
March 1 5, 1 976. : Department
All authors
J Roentg.nol
of Radiology.
1 27 : 1 71 -1 74,
1976
University
excluded image
patients,
641
as patient
of Iowa
this
disagreement
months
of this
from
the study
were
technically
radionuclide
study.
there
independently Increased
the
early
because
1 5 CT
unsatisfactory.
and CT studies
were
without
experience
in 54 patients.
To date,
disease
Since
these
study, Similarly,
in patients
occlusive
of har-
71 patients
were
in whom
clinical
information
in CT interpretation
In the
by
resolved
38 patients,
remaining
cannot
be established
conditions
they we
were have
without
disease.
These
cannot
excluded
dis-
in six patients
excluded
clinical
be
diagnosed
in the calculation diagnoses
of reduced
manifestations
exclusions
are
with
by
the
of percarotid
of cerebrovascular
not intended
the importance of these findings but rather comparison of the two techniques.
else-
to permit
to minimize a reasonable
maResults
Among the 641 patients, 1 1 4 had intracranial tumors (table 1 ). A breakdown of the lesions which were false
system
Hospitals
During
charts.
to approximately
1 2 months, CT images were displayed on an 80 x 80 matrix and thereafter by a 1 60 x 60 matrix system. It is important to emphasize that during the time interval
I
radiologists.
flow
20% of examinations by July 1 975. Contrast material was only given after review of the initial nonenhanced CT images. During the first
Received
were
radionuclide
reviewed
four
centages.
ob-
of contrast
early
radionuclide
earlier
as described
by the injection
one
as well
callosum.
disease.
CT technique
where
posterior
on patients
normal boning
The
and/or equivocal
disease.
contradictory results by the two techniques. Therefore, positive radionuclide scans on three of these patients and positive CT scans on the other three patients are considered false positives in this analysis. Of the 641 patients, 1 35 were diagnosed by the CT study as haying hydrocephalus, porencephaly, cerebral atrophies, benign cysts, or developmental abnormalities such as agenesis of the corpus
the range of 20-25 mCi, with proportionately smaller doses for children. Anterior dynamic images as well as four-view static images at 10 mm and 2 hr after injection were routinely obtained. Commonly 3 or 4 hr delayed
remaining
analysis.
or cerebrovascular
intracranial lesions; pathologic lesions were
ultimately not established. The radionuclide studies were all made on a Nuclear Chicago Pho-gamma Ill camera utilizing 99”Tc pertechnetate after a blocking dose of 400 mg of potassium perchlorate. Adult doses were in
tamed
intracranial
initially
to the traditional
agreement remained. In all patients, the final diagnosis was confirmed by surgery, autopsy, angiography, pneumoencephalography, or the subsequent clinical course. Equivocal CT studies on three patients (one ultimately proved to have disease, two proved normal) are considered one false negative and two false positive in this
Methods
discrete
In the
spectively
November 1 973 and April 1975, relatively concurrent CT and radionuclide studies were performed on 657 patients. Time intervals between the two examinations varied from 1 week in pa-
to 3 weeks
malfunctions
a return
one study was initially considered positive while the other was negative, and 24 patients in whom one of the studies (primarily CT) was considered equivocal. All of these studies were netno-
Between
tients with trauma, suspected brain abscess, disease ; 2 weeks in patients with other discrete
and
In the
intra-
disease.
and
frequent
necessitated
to
patients
images reviewed
The purpose of this report is to compare our initial experience in CT with radionuclide scintignaphy and to attempt to assess the usefulness and limitations of each technique. Subjects
including
which
approach
Sixteen
of all neuroinformation brain scan
varied,
scanner
initial radionuclide studies 40% of patients with initial studies. The reasons for
circumstances.
brain While
on the utilization
H. CORNELL,
months of this study, patients with positive findings demonstrated by either technique often had the other examination for the sake of comparison. Later, patients with negative or equivocal results on either technique frequently had the other examination to satisfy a high index of clinical suspicion. It should also be emphasized that because of the function of this referral center, patient selectivity is quite high. To a large degree, this selectivity accounts for the numben of patients with neoplasms compared to those with cerebrovascular disease ; the latter are not referred to us except in unusual
rapidly
pneumoencephalography.
to have an effect
role
has
are
EMI
diagnostic
be
by Hounsfield
[2]
techniques, the unique anatomic threatens to replace the radionuclide
its traditional
must
selectivity
of the
light.
cranial disease. At first glance, noninvasive manner information ously
results
STEVEN
comparison only 25% of patients with had subsequent CT studies ; conversely, CT studies had subsequent radionuclide
mont in diagnosis can be expected if both techniques are employed. It is emphasized that the radionuclide studies used routinely included what are rightfully considered
adjunctive
T. GO,
in the
negative of this
and
by one
The results
Clinics,
171
Iowa
City.
or both
techniques
in 86 patients
Iowa
52242.
Address
with
reprint
is shown
nonneoplastic
requests
in table
disease
to J. H. Christie.
2.
are
CHRISTIE
172
ET AL
TABLE
1
Neoplastic
Disease
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Total No.
Location
Cases
Supratentorial
79
Baseofbraint Posterior fossa Total
11
in parentheses
t Supratentorial
though
are percentages.
in juxtaposition
TABLE Analysis
of
False
‘
3 4 1 2 (1 1 )
17 90 (79)
structures
CT-’ RN
5
5
RN=radionuclide
to bony
-
68
24 1 14
Note-Numbers . False negative.
CT-’ RN
CT+ RN ‘
CT+ RN
+
CT
‘
RN
+
+
3
3
71
71
94
1 1 5 (4)
2 2 7 (6)
7 19 97 (85)
6 18 95 (83)
73 83 89
study.
at base
of skull.
shown in table 3. The patients with vascular disease have been categorized time between onset of clinical symptoms
2
Negative
%
+
occlusive cerebroaccording to the and examination.
Examinations
Discussion Examination
No.
CT failed False negative CT and RN: Supratentorial: Microglioma
of corpus
callosum
3 mm parasaggital
meningioma,
Metastatic
breast
tumor,
(autopsy)
1
right frontal
(clinical
diagnosis
(autopsy) not
con-
2
firmed) Frontal
parietal
mass
(diagnosis
: malignant
by
angiography) Supratentorial,
base
Pituitary
of
skull:
2
adenoma
Craniopharyngioma Posterior
Fossa:
Brain
stem glioma
Metastatic
tumor,
3 cerebellopontine
angle
12
Total False negative CT, positive Supratentorial: Metastatic tumor Primary
tumors
Supratentonial, using Posterior
RN:
(diagnosed
malignant
base of skull image
fossa
(sphenoid
by angiography)
wing
2
meningioma 1
enhancement) (malignant
cerebellar
glioma)
__i._
Total
Positive
CT,
5 false
negative
Pituitary
tonal
2 cells
adenoma
Craniopharyngioma
Posterior fossa: Brain stem glioma Cerebellar medulloblastoma Total
1 7 of the
1 1 4 neoplasms
; that
is, 15%
rendered more likely if both the radionuclide and CT techniques are utilized ; this view is currently held for supraten-
RN:
Supratentorial: Low grade glioma Focal proliferation of Ieukemic Supratentorial, base of skull:
to detect
of the CT scans yielded false negative results. Four of these failures occurred early in our experience and probably could have been avoided by the use of imaae enhancement with circulating contrast material. Two of the missed lesions were found incidentally at necropsy and proved to be of a size rendering detection unlikely. Pituitary adenomas which are in most instances readily detected on plain skull radiographs are difficult to diagnose by both CT and radionuclide techniques; diagnosis by the scintiscan is especially hampered by the normal background activity at the base of the calvarium. Posterior fossa neoplasms that have always proved difficult to demonstrate on radionuclide studies have also been difficult to diagnose on CT studies [2, 5]. Notwithstanding these observations, our results indicate a 90% detection probability with each technique individually or a 95% probability for both examinations combined, provided lesions confined to the brain stem are excluded. The present state of the art does not permit demonstration of brain stem lesions by scintigraphy unless the tumor extends beyond the normal confines of the brain stem [6]. A greaten potential for detection of brain stem lesions has been anticipated for the CT technique [7] but must await further confirmation. Finally, the diagnosis of neoplasm is
lesions,
including
those
near
the
base
brain,
as
1 1
While efficient
1
tive
1
tumors
1
interpretation of the CT study was handicapped by artifacts produced by a metallic shunt in the same plane. Recently, Leonard et al. [1 0] have reemphasized the ability to differentiate on postoperative radionuclide images between surgical changes and recurrent tumor in 21 of 30 patients; in eight of the remaining nine cases, the presence or absence
---
_____
lesions. However, at best.
of the
well as for infratentonial in detection is moderate
the improvement
others have reported that CT studies are more than radionuclide studies in following postopera-
cases were
[8, 9],
in our limited
detected
utilizing
comparison both
techniques.
all six recurrent In one
case,
COMPARISON
OF CT AND
TABLE
BRAIN
SCANS
173
3
Nonneoplastic
Disease
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Total
Type
Vascular
occlusive
CT+ RN
No. Cases
-
CT-’ RN
‘
CT+ RN -
+
RN
‘
CT
+
%
+
+
:t
disease
8weeks
10
2
6
0
13
7
0
2 1
0 0
Brain
5
hemorrhage
Arteniovenous malformation Large aneurysm
3 2
Subdural
5
7
80
2
22 3 2
14 2 4
81 60 40
0
6
7
13
1 0
0 1
3 1
2 2
.
.
100
100 100
9
7
0
1
1
8
8
100
Cerebral
contusion
2
0
0
1
1
1
1
100
Cerebral
abscess
5
5
0
0
0
5
5
100
hematoma
Total C
86
False
44
:
according
to time
enhancement
with
of tumor
could
In those
instances
between
onset
contrast
disease
are
of clinical
symptoms
be determined
by subsequent
where
clips
essentially
patients
clinical
were
metallic
as expected.
referred
manifestations,
cases
renders
and
repeat
on shunt
studies
valves
pro-
Since
because
the
lack
an analysis
the
majority
of atypical
of histologic
presumptive
of
on unusual proof
at best.
in most
Our
and
previous
reports
results
return
to normal
[1 1 ] indicating
in most
cases
after
8 weeks.
Our
data also conform to those of Paxton and Ambrose [5] who found CT studies 1 00% accurate in diagnosis during the first 7 days, while positive findings decrease progressively to about
50%
or less of cases
CT studies nique
are clearly
in cerebral,
In our series
cerebellar,
as well
1 to 3 weeks
superior
to the
thereafter. radionuclide
or intraventricular
as in those
reported
tech-
57
58
83
by others
hemorrhage
have
been
considerable of scintiscans
disagreement in this regard
The detection namic radionuclide are
of
reported
identified
contrast
material,
with
man
et al. [1 7]
the unsuspected tive as desirable.
persists [14-16].
suggest
[5, 12,
images
our results the
arteriovenous
investigators, ultimate
value
malformations by dyestablished. While these
in CT
that
many
as to the
arteniovenous studies is well
readily
ment
by
and
nonehanced
malformation
after
enhance-
those
of Press-
CT study
casionally may be useful provided dynamic studies are performed. In chronic subdunal hematoma, both techniques are useful and were found to be complementary in the present series. The few brain abscesses in our series were readily detected by both techniques, although one could only be demonstrated by CT after image enhancement with contrast material. Davis et al. [21 ] have suggested that the radionuclide study may be more sensitive in early abscess formation. A word of caution seems appropriate in using these data to evaluate the relative efficiency of scintigraphy and CT as screening procedures for brain disorders. Because of our longstanding interest in nuclear brain imaging and because of the extensive preselection of patients referred for brain imaging in this tertiary referral center, the “routine” nuclear scan as performed in this department cannot realistically be viewed as a screening procedure. Virtually every brain scan includes
hemorrhage.
1 3], the diagnosis of hemorrhage within the brain has been 1 00% accurate. While positive radionuclide images in brain
lesions
14
examination.
that static radionuclide images tend to be normal in the first week after onset of symptoms, become grosslly abnormal 1 -3 weeks support
later,
13
material.
duce CT images of poor quality [8, 9], it is reasonable to believe that radionuclide studies will continue to be useful. Our comparative results in cerebrovascular occlusive our
15
negative.
t Categorized No image
-
CT-’ RN
+
for
is not as sensi-
scans,
results head
pertaining trauma are
to the similar
where
[1, 7, 18-20].
In acute
tomas,
CT is specific,
while
evaluation to those
subdural
the radionuclide
of acute and described else-
or epidural
technique
hema-
oc-
are rightfully such
and,
as deemed monitored
as
considered
dynamic
commonly,
sequential
necessary examination.
adjunctive
images,
scanning
immediate
scans
and
static
delayed
scans
during the progress of the continually In the usual clinical setting, this in-
clusive examination routine may be impractical and difficult to justify in terms of present day medical economic realities. These considerations suggest that the sensitivity and accuracy
attributed
to the
cannot
always
be extended
study
which
tamed the
nuclide. data
nuclear
traditionally
at a single
sented
Our chronic
what
procedures
In
fixed
includes time
an
earlier
showing
that
interval
obtained
1 hr after
significantly
nuclide
in the
adjunctive
series
radionuclide
only
static
1-2
hr after
images
[22], scanning
ob-
injection we
of pre-
procedures
possible the delineation of on “routine” static views
injection.
underestimate
present
screening
communication
on 1 08 selected patients made 40 lesions that escaped detection ably
study
to the
the
Thus relative
these
data
efficacy
probof CT
CHRISTIE
174
TABLE Review
ET AL.
4
TABLE
of Cases
5
Comparative
Accuracy (%)
Accuracy
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No Type
26.5 58.7
134 297
True positive CT and RN True negative CT and RN False negative: CT and RN CT alone RN alone False positive:
27 19 21
Neoplasm
RN alone Subtotal by CT*
7.
atrophies.
benign
cyst.
and
developmental
cattosum.
Davis
DO,
Pressman
diagnosis
compared
tional “routine” The discussion
brain scans. so far has dealt
can usually niques. CT
expected to the capability
formation ness
on
of
These
additional
conditions
mental losum.
studies include
hydrocephalus,
with
brain
brain
in which has
entities
atrophies,
abnormalities In the present
to the more
be diagnosed of providing
disorders
radionuclide
long
disorders
that
by both significant
techin-
the
ineffective-
been
such
benign
tradi-
recognized.
as porencephaly, cysts,
and
develop-
such as agenesis of the corpus series, these disorders comprise
cal21 %
of all patients. This
study
imaging both
suggests
give
intracranial
that
reasonably disease
techniques
both
similar
(table
is superior
to be on the order
greater for conclusion limited
radionuclide
precision
4)
and
that
to either
sense, each modality complements ment in diagnosis to be expected pears
and
CT
in the diagnosis
of
the
alone
combination (table
of
5) ; in this
the other. The improveusing both techniques ap-
of 5% for neoplasms
vascular anomalies must be considered
and trauma. in the light
However, this of a relatively
REFERENCES GN :
tomography
Stroke 1 4.
nuclide
: 679-695,
100
100
82
82
100
of
the
brain.
Radiology
gliomas. tomography
JM, Hockscanner in
intracranial
neoplasms.
and
intraventnicular
JA,
hemorrhage.
1974
A : The detection of with angiography.
negative
A : Brain
Br MedJ
scanning.
cerebrovascular lesions. , 1972 FC, Radcliffe WB : Radio-
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DE,
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in brain
scanning
(Stockh)
Adcock
imaging
results
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CB.
Computer
21
4,
tomography
of
the
head
: an
1975
Hopkins GB, Kristensen raphy in the radionuclide Nuc! Med 1 4 : 288-290, .
Davis
KR,
Cerebral
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early evaluation. Mayo Clin Proc 49 : 1 2-37, 1974 Baker HL Jr. Campbell JK, Houser OW, Reese DF : Early expenience with the E.M.I. scanner for study of the brain. Radiol-
J
1974
the
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New PFJ, Scott WA, Schnur JA, Davis KR, Taveras JM : Computenized axial tomography with the E.M.I. scanner. Radiology 110:109-123, 1974 5. Paxton R, Ambrose J : The E.M.I. scanner : a brief review of the first 650 patients. Br J Radio! 47 : 530-565. 1974 6. Feigin DS, Welch DM, Siegel BA, James AE Jr : The efficacy
of
111 :211-212, 1974 1 7. Pressman BD, Kirkwood JR. Davis DO : Computerized transverse tomographyof vascular lesions of the brain. I. Arteriovenous malformations. Am J Roentgenol 1 24 : 208-21 4, 1975 18. Baker HL, Jr. Campbell JK, Houser OW, Reese DF, Sheedy DF,
1973 Neurosurg 40
100
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intracerebral
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Halman
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x-ray
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2. Ambrose J : Computerized transverse axial scanning (tomognaphy). II. Clinical application. Br J Radio! 46 :1023-1047, J : Computerized
of
Burrows
1022, 1973
3. Ambrose
52 100 80
1 3. Wise G, Brockenbrough EC, Marty R, Griep carotid artery obstruction : a correlation
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I. Description
85
BD : Computerized
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Radiology
transverse axial scanning of system. Br J Radio! 46:1016-
(tomography).
Computerized
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62 54 80
52 13 5
.
Both
9. Pendergrass HP, McKusick KA, New PFJ, Potsaid MS : Relative efficacy of radionuclide imaging and computed tomography of the brain. Radiology 1 1 6 : 363-366, 1975 10. Leonard JR. Witherspoon LA, Mathaley MS Jr. Goodrich JK: Value of sequential postoperative brain scans in patients with anaplastic gliomas. J Neurosurg 42 : 551-556, 1975 1 1 . Quinn JL Ill : Aids for the diagnosis of cerebral vascular disease brain scanning, in Cerebral Vascular Diseases, 6th Conference, edited by Siekert AT, Whisnant JP, New York, Grune & Stratton, 1 968, pp 179-189 1 2. Scott WA, New PFJ, Davis KR, Schnur JA : Computerized axial
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and somewhat
experience.
1 . Hounsfield
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Radiology procedure
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of the brain scan in diagnosis 116:117-120, 1975
135
‘ Hydrocephalus. porencephaly. cerebrat abnormalities such as agenesis of the corpus
RN
1.0 .6
641
as a screening
disease
Infection
506
Total
scans
Cases
114
Vascular occlusive Brain hemorrhage Vascularanomalies
5.3 3.8 4.2
5 3
diagnosed
No.
Trauma
CT alone
Exclusively
of Lesion
Taveras
infarction
JM,
: Rapid sequential detection of subdural 1973
KAB
New
Schnur
JA,
Roberson
J
GH:
diagnosis
evaluation
by computerized tomography: of findings. Am J Roentgenol 1 24:
analysis
and
643-660, Christie
1975 JH, Go AT, Suzuki
quential
brain
Radiology
PFJ,
scintiphotoghematomas.
scanning
114:381-387,
Y, Tonami
as an adjunctive
1975
N, Schapiro scanning
AL : Seprocedure.
Tomography Diagnosis
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JAMES
H. CHRISTIE,1
and Radionuclide Studies of Intracranial Disease
HIROFUMI AND
MORI, ROLF
RAYMUNDO L. SCHAPIRO
The accuracy of CT and radionuclide studies in the diagnosis of intracranial disease is analyzed based on experience in 641 patients. Results indicate that both modalities give reasonably similar precision and that a modest improve-
scanning
considered
in this
Computed
tomography
and
initially
achieved
procedures,
so that
this
(CT)
reported
introduced
by Ambrose
widespread
obtained
scans,
acclaim
by the
angiography,
CT is certain radiologic provides
in 1 973
in the
diagnosis
it appears comparable
combination
and
of
cranial
[1]
of
intra-
to provide in a to that previ-
radionuclide
as the screening
test for suspected
it in
in patients
in whom
to
clarify
studies intracranial
tenial
stereoscopic
earlier
who
findings
were strongly
used
(EMI)
is essentially
[3, 4]. Image enhancement initially
was
or
images to
were
confirm
suspected
used
sparingly
but
increased
Am
March 1 5, 1 976. : Department
All authors
J Roentg.nol
of Radiology.
1 27 : 1 71 -1 74,
1976
University
excluded image
patients,
641
as patient
of Iowa
this
disagreement
months
of this
from
the study
were
technically
radionuclide
study.
there
independently Increased
the
early
because
1 5 CT
unsatisfactory.
and CT studies
were
without
experience
in 54 patients.
To date,
disease
Since
these
study, Similarly,
in patients
occlusive
of har-
71 patients
were
in whom
clinical
information
in CT interpretation
In the
by
resolved
38 patients,
remaining
cannot
be established
conditions
they we
were have
without
disease.
These
cannot
excluded
dis-
in six patients
excluded
clinical
be
diagnosed
in the calculation diagnoses
of reduced
manifestations
exclusions
are
with
by
the
of percarotid
of cerebrovascular
not intended
the importance of these findings but rather comparison of the two techniques.
else-
to permit
to minimize a reasonable
maResults
Among the 641 patients, 1 1 4 had intracranial tumors (table 1 ). A breakdown of the lesions which were false
system
Hospitals
During
charts.
to approximately
1 2 months, CT images were displayed on an 80 x 80 matrix and thereafter by a 1 60 x 60 matrix system. It is important to emphasize that during the time interval
I
radiologists.
flow
20% of examinations by July 1 975. Contrast material was only given after review of the initial nonenhanced CT images. During the first
Received
were
radionuclide
reviewed
four
centages.
ob-
of contrast
early
radionuclide
earlier
as described
by the injection
one
as well
callosum.
disease.
CT technique
where
posterior
on patients
normal boning
The
and/or equivocal
disease.
contradictory results by the two techniques. Therefore, positive radionuclide scans on three of these patients and positive CT scans on the other three patients are considered false positives in this analysis. Of the 641 patients, 1 35 were diagnosed by the CT study as haying hydrocephalus, porencephaly, cerebral atrophies, benign cysts, or developmental abnormalities such as agenesis of the corpus
the range of 20-25 mCi, with proportionately smaller doses for children. Anterior dynamic images as well as four-view static images at 10 mm and 2 hr after injection were routinely obtained. Commonly 3 or 4 hr delayed
remaining
analysis.
or cerebrovascular
intracranial lesions; pathologic lesions were
ultimately not established. The radionuclide studies were all made on a Nuclear Chicago Pho-gamma Ill camera utilizing 99”Tc pertechnetate after a blocking dose of 400 mg of potassium perchlorate. Adult doses were in
tamed
intracranial
initially
to the traditional
agreement remained. In all patients, the final diagnosis was confirmed by surgery, autopsy, angiography, pneumoencephalography, or the subsequent clinical course. Equivocal CT studies on three patients (one ultimately proved to have disease, two proved normal) are considered one false negative and two false positive in this
Methods
discrete
In the
spectively
November 1 973 and April 1975, relatively concurrent CT and radionuclide studies were performed on 657 patients. Time intervals between the two examinations varied from 1 week in pa-
to 3 weeks
malfunctions
a return
one study was initially considered positive while the other was negative, and 24 patients in whom one of the studies (primarily CT) was considered equivocal. All of these studies were netno-
Between
tients with trauma, suspected brain abscess, disease ; 2 weeks in patients with other discrete
and
In the
intra-
disease.
and
frequent
necessitated
to
patients
images reviewed
The purpose of this report is to compare our initial experience in CT with radionuclide scintignaphy and to attempt to assess the usefulness and limitations of each technique. Subjects
including
which
approach
Sixteen
of all neuroinformation brain scan
varied,
scanner
initial radionuclide studies 40% of patients with initial studies. The reasons for
circumstances.
brain While
on the utilization
H. CORNELL,
months of this study, patients with positive findings demonstrated by either technique often had the other examination for the sake of comparison. Later, patients with negative or equivocal results on either technique frequently had the other examination to satisfy a high index of clinical suspicion. It should also be emphasized that because of the function of this referral center, patient selectivity is quite high. To a large degree, this selectivity accounts for the numben of patients with neoplasms compared to those with cerebrovascular disease ; the latter are not referred to us except in unusual
rapidly
pneumoencephalography.
to have an effect
role
has
are
EMI
diagnostic
be
by Hounsfield
[2]
techniques, the unique anatomic threatens to replace the radionuclide
its traditional
must
selectivity
of the
light.
cranial disease. At first glance, noninvasive manner information ously
results
STEVEN
comparison only 25% of patients with had subsequent CT studies ; conversely, CT studies had subsequent radionuclide
mont in diagnosis can be expected if both techniques are employed. It is emphasized that the radionuclide studies used routinely included what are rightfully considered
adjunctive
T. GO,
in the
negative of this
and
by one
The results
Clinics,
171
Iowa
City.
or both
techniques
in 86 patients
Iowa
52242.
Address
with
reprint
is shown
nonneoplastic
requests
in table
disease
to J. H. Christie.
2.
are
CHRISTIE
172
ET AL
TABLE
1
Neoplastic
Disease
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Total No.
Location
Cases
Supratentorial
79
Baseofbraint Posterior fossa Total
11
in parentheses
t Supratentorial
though
are percentages.
in juxtaposition
TABLE Analysis
of
False
‘
3 4 1 2 (1 1 )
17 90 (79)
structures
CT-’ RN
5
5
RN=radionuclide
to bony
-
68
24 1 14
Note-Numbers . False negative.
CT-’ RN
CT+ RN ‘
CT+ RN
+
CT
‘
RN
+
+
3
3
71
71
94
1 1 5 (4)
2 2 7 (6)
7 19 97 (85)
6 18 95 (83)
73 83 89
study.
at base
of skull.
shown in table 3. The patients with vascular disease have been categorized time between onset of clinical symptoms
2
Negative
%
+
occlusive cerebroaccording to the and examination.
Examinations
Discussion Examination
No.
CT failed False negative CT and RN: Supratentorial: Microglioma
of corpus
callosum
3 mm parasaggital
meningioma,
Metastatic
breast
tumor,
(autopsy)
1
right frontal
(clinical
diagnosis
(autopsy) not
con-
2
firmed) Frontal
parietal
mass
(diagnosis
: malignant
by
angiography) Supratentorial,
base
Pituitary
of
skull:
2
adenoma
Craniopharyngioma Posterior
Fossa:
Brain
stem glioma
Metastatic
tumor,
3 cerebellopontine
angle
12
Total False negative CT, positive Supratentorial: Metastatic tumor Primary
tumors
Supratentonial, using Posterior
RN:
(diagnosed
malignant
base of skull image
fossa
(sphenoid
by angiography)
wing
2
meningioma 1
enhancement) (malignant
cerebellar
glioma)
__i._
Total
Positive
CT,
5 false
negative
Pituitary
tonal
2 cells
adenoma
Craniopharyngioma
Posterior fossa: Brain stem glioma Cerebellar medulloblastoma Total
1 7 of the
1 1 4 neoplasms
; that
is, 15%
rendered more likely if both the radionuclide and CT techniques are utilized ; this view is currently held for supraten-
RN:
Supratentorial: Low grade glioma Focal proliferation of Ieukemic Supratentorial, base of skull:
to detect
of the CT scans yielded false negative results. Four of these failures occurred early in our experience and probably could have been avoided by the use of imaae enhancement with circulating contrast material. Two of the missed lesions were found incidentally at necropsy and proved to be of a size rendering detection unlikely. Pituitary adenomas which are in most instances readily detected on plain skull radiographs are difficult to diagnose by both CT and radionuclide techniques; diagnosis by the scintiscan is especially hampered by the normal background activity at the base of the calvarium. Posterior fossa neoplasms that have always proved difficult to demonstrate on radionuclide studies have also been difficult to diagnose on CT studies [2, 5]. Notwithstanding these observations, our results indicate a 90% detection probability with each technique individually or a 95% probability for both examinations combined, provided lesions confined to the brain stem are excluded. The present state of the art does not permit demonstration of brain stem lesions by scintigraphy unless the tumor extends beyond the normal confines of the brain stem [6]. A greaten potential for detection of brain stem lesions has been anticipated for the CT technique [7] but must await further confirmation. Finally, the diagnosis of neoplasm is
lesions,
including
those
near
the
base
brain,
as
1 1
While efficient
1
tive
1
tumors
1
interpretation of the CT study was handicapped by artifacts produced by a metallic shunt in the same plane. Recently, Leonard et al. [1 0] have reemphasized the ability to differentiate on postoperative radionuclide images between surgical changes and recurrent tumor in 21 of 30 patients; in eight of the remaining nine cases, the presence or absence
---
_____
lesions. However, at best.
of the
well as for infratentonial in detection is moderate
the improvement
others have reported that CT studies are more than radionuclide studies in following postopera-
cases were
[8, 9],
in our limited
detected
utilizing
comparison both
techniques.
all six recurrent In one
case,
COMPARISON
OF CT AND
TABLE
BRAIN
SCANS
173
3
Nonneoplastic
Disease
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Total
Type
Vascular
occlusive
CT+ RN
No. Cases
-
CT-’ RN
‘
CT+ RN -
+
RN
‘
CT
+
%
+
+
:t
disease
8weeks
10
2
6
0
13
7
0
2 1
0 0
Brain
5
hemorrhage
Arteniovenous malformation Large aneurysm
3 2
Subdural
5
7
80
2
22 3 2
14 2 4
81 60 40
0
6
7
13
1 0
0 1
3 1
2 2
.
.
100
100 100
9
7
0
1
1
8
8
100
Cerebral
contusion
2
0
0
1
1
1
1
100
Cerebral
abscess
5
5
0
0
0
5
5
100
hematoma
Total C
86
False
44
:
according
to time
enhancement
with
of tumor
could
In those
instances
between
onset
contrast
disease
are
of clinical
symptoms
be determined
by subsequent
where
clips
essentially
patients
clinical
were
metallic
as expected.
referred
manifestations,
cases
renders
and
repeat
on shunt
studies
valves
pro-
Since
because
the
lack
an analysis
the
majority
of atypical
of histologic
presumptive
of
on unusual proof
at best.
in most
Our
and
previous
reports
results
return
to normal
[1 1 ] indicating
in most
cases
after
8 weeks.
Our
data also conform to those of Paxton and Ambrose [5] who found CT studies 1 00% accurate in diagnosis during the first 7 days, while positive findings decrease progressively to about
50%
or less of cases
CT studies nique
are clearly
in cerebral,
In our series
cerebellar,
as well
1 to 3 weeks
superior
to the
thereafter. radionuclide
or intraventricular
as in those
reported
tech-
57
58
83
by others
hemorrhage
have
been
considerable of scintiscans
disagreement in this regard
The detection namic radionuclide are
of
reported
identified
contrast
material,
with
man
et al. [1 7]
the unsuspected tive as desirable.
persists [14-16].
suggest
[5, 12,
images
our results the
arteriovenous
investigators, ultimate
value
malformations by dyestablished. While these
in CT
that
many
as to the
arteniovenous studies is well
readily
ment
by
and
nonehanced
malformation
after
enhance-
those
of Press-
CT study
casionally may be useful provided dynamic studies are performed. In chronic subdunal hematoma, both techniques are useful and were found to be complementary in the present series. The few brain abscesses in our series were readily detected by both techniques, although one could only be demonstrated by CT after image enhancement with contrast material. Davis et al. [21 ] have suggested that the radionuclide study may be more sensitive in early abscess formation. A word of caution seems appropriate in using these data to evaluate the relative efficiency of scintigraphy and CT as screening procedures for brain disorders. Because of our longstanding interest in nuclear brain imaging and because of the extensive preselection of patients referred for brain imaging in this tertiary referral center, the “routine” nuclear scan as performed in this department cannot realistically be viewed as a screening procedure. Virtually every brain scan includes
hemorrhage.
1 3], the diagnosis of hemorrhage within the brain has been 1 00% accurate. While positive radionuclide images in brain
lesions
14
examination.
that static radionuclide images tend to be normal in the first week after onset of symptoms, become grosslly abnormal 1 -3 weeks support
later,
13
material.
duce CT images of poor quality [8, 9], it is reasonable to believe that radionuclide studies will continue to be useful. Our comparative results in cerebrovascular occlusive our
15
negative.
t Categorized No image
-
CT-’ RN
+
for
is not as sensi-
scans,
results head
pertaining trauma are
to the similar
where
[1, 7, 18-20].
In acute
tomas,
CT is specific,
while
evaluation to those
subdural
the radionuclide
of acute and described else-
or epidural
technique
hema-
oc-
are rightfully such
and,
as deemed monitored
as
considered
dynamic
commonly,
sequential
necessary examination.
adjunctive
images,
scanning
immediate
scans
and
static
delayed
scans
during the progress of the continually In the usual clinical setting, this in-
clusive examination routine may be impractical and difficult to justify in terms of present day medical economic realities. These considerations suggest that the sensitivity and accuracy
attributed
to the
cannot
always
be extended
study
which
tamed the
nuclide. data
nuclear
traditionally
at a single
sented
Our chronic
what
procedures
In
fixed
includes time
an
earlier
showing
that
interval
obtained
1 hr after
significantly
nuclide
in the
adjunctive
series
radionuclide
only
static
1-2
hr after
images
[22], scanning
ob-
injection we
of pre-
procedures
possible the delineation of on “routine” static views
injection.
underestimate
present
screening
communication
on 1 08 selected patients made 40 lesions that escaped detection ably
study
to the
the
Thus relative
these
data
efficacy
probof CT
CHRISTIE
174
TABLE Review
ET AL.
4
TABLE
of Cases
5
Comparative
Accuracy (%)
Accuracy
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No Type
26.5 58.7
134 297
True positive CT and RN True negative CT and RN False negative: CT and RN CT alone RN alone False positive:
27 19 21
Neoplasm
RN alone Subtotal by CT*
7.
atrophies.
benign
cyst.
and
developmental
cattosum.
Davis
DO,
Pressman
diagnosis
compared
tional “routine” The discussion
brain scans. so far has dealt
can usually niques. CT
expected to the capability
formation ness
on
of
These
additional
conditions
mental losum.
studies include
hydrocephalus,
with
brain
brain
in which has
entities
atrophies,
abnormalities In the present
to the more
be diagnosed of providing
disorders
radionuclide
long
disorders
that
by both significant
techin-
the
ineffective-
been
such
benign
tradi-
recognized.
as porencephaly, cysts,
and
develop-
such as agenesis of the corpus series, these disorders comprise
cal21 %
of all patients. This
study
imaging both
suggests
give
intracranial
that
reasonably disease
techniques
both
similar
(table
is superior
to be on the order
greater for conclusion limited
radionuclide
precision
4)
and
that
to either
sense, each modality complements ment in diagnosis to be expected pears
and
CT
in the diagnosis
of
the
alone
combination (table
of
5) ; in this
the other. The improveusing both techniques ap-
of 5% for neoplasms
vascular anomalies must be considered
and trauma. in the light
However, this of a relatively
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‘ Hydrocephalus. porencephaly. cerebrat abnormalities such as agenesis of the corpus
RN
1.0 .6
641
as a screening
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Infection
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Total
scans
Cases
114
Vascular occlusive Brain hemorrhage Vascularanomalies
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5 3
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No.
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Exclusively
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Taveras
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Schnur
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Roberson
J
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