Computerized Tomography in the Detection of Intracranial Metastases in Children

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Computerized

Tomography

in the Detection

of

Intracranial

Metastases

in Children

Paul G. Dyment, M.D., A. David Rothner, M.D., Paul M. Duchesneau, M.D., and Meredith

A. Weinstein, M.D.

Iromsm tll(’ SC(tiO,lS Oil Pediatric !-le:natologq-On(-ology, Pediatric Veurology. (111(1 ‘S(’ururadu)logy, time

Ch-reland Clinic I000(lation, Cletela;id. Ohio

ABSTRACT. Computerized tomnographv l)raiu scamis pro-dtmce sectiomial tomiiogramns of the brain sImi)stance which demiionstrate intracramiial lesiomis. The procedure is safe and painless, amid can be done on an outpatient basis. Three children with malignant disease had imitracranial miietastases demlionstrated Imsimig this techmiique during a recent six-miionth period at the Cleveland Clinic. Pediatrics, 58:72-77, 1976,

(:ANCEB, COMPUTERIZED TOMO(;RAPHY, BRAIN SCAN.

In 1973 Ambrose and Hounsfield’ reported an

ingenious

roentgenographic

technique

in which

a

digital

computer

was

used

to measure

variations

ili

X-ray

absorption.

The

clinical

application

of

this technique of computerized tomography (CT) has been an ability to achieve sectional tomo-grams of the brain substance to a degree of clarity not generally achieved with other

neuroradio-logic

techniques.

Little

has

been

written

about

the

problem

of

the child with cerebral metastatic disease, although Vanucci and Baten2 have recently

reported

that

6% of children

with

fatal

malignan-cies will have one or more cerebral metastases present at the time of autopsy. This new radio-logic technique makes possible the accurate diag-nosis of cerebral metastases safely and rapidly

without

risk

or discomfort.

This

report

describes

the

use

of

CT

in

confirming the clinical impression of intracranial

nietastatic

disease

in three

children

at this

institu-tion during a recent six-month period.

TECHNIQUE

Although

the

CT

scanner

is

an

enormously

complex

instrument,

an

understanding

of

the

basic

principles

is helpful

to the

clinician.

Tech-nical reviews of the system have been published’

and

should

be

consulted

by

those

interested

in a

more

detailed

description

of this

technique.

The

CT

system

utilizes a narrow beam of

X-rays which traverse the skull while 160 readings are taken (Fig. 1, scan 1). The X-ray source and

detector

then

rotate

one

degree

and

another

scan

is taken. This is repeated 180 times for each cross-section of the brain (Fig. 1, scan 2). Each

cross-section

is a tomograph

representing

1.3 cm

of

brain

tissue.

Serial

tomographs

are

obtained

from

the base of the skull to the top of the calvarium.

By

solving

equations

of

absorption

coefficients,

the

computer produces both a numerical print-out and by display on a television monitor, a

black-and-white

picture

which

is then

recorded

by

Polaroid

photography.

Tissue

densities

range

from

black

(air)

to white

(bone)

(Fig.

2).

The procedure requires that the child be still

for 20 minutes,

with

the

upper

part

of the

head

in

the scanner (Fig. 3). We generally achieve this

(Received September 21, 1975; revision accepted for publi-cation January 5, 1976.)

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X-ray detector

Top View

detector

SCAN 2

Television monitor Numerical print out

Case 2

Case 3

degree of sedation with chloral hydrate given

orally. If a tumor is suspected, radiographic

contrast material is given intravenously before

the

procedure

in

order

to

heighten

tissue

contrasts.

We use the commercially available EMI

Scan-ner, developed and manufactured by a British

firm.#{176}

PATIENTS

Case 1

A 2-year-old boy with a large abdominal mass was examined here in May 1974. Multiple pulmonary metastases were present and he underwent a right hepatic lobectomy

for a hepatocellular carcinoma. Despite a combination chemotherapy regimen of vincristine, fluorouracil, and cyclophosphamide the size of his pulmonary lesions increased. This progression continued despite investigational chemotherapy consisting of ICRF-159 (NSC-129943) and the combination of adriamycin and dimethyl triazeno imidazole carboxamide (NSC-45388).

Four months after his laparotomy he began to have daily headaches associated with occasional vomiting. During an

outpatient visit physical examination revealed papilledema,

a wide-based gait, and a new 5 x 3 cm abdominal mass. A CT brain scan demonstrated a large area of increased uptake

(tumor

mass) in the right frontal lobe surrounded by a large area of decreased uptake (edema) (Fig. 4). No further therapy was undertaken and the child died in a community hospital five weeks later, after the development of increasing central nervous system (CNS) deterioration including seizures and left hemiparesis. Permission for a postmortem examination was refused.

An 8#{189}-year-old girl had a small cell sarcoma excised from her left ankle in October 1972. There was no evidence of metastatic .thsease and the tumor appeared to have been totally removed. She received irradiation to her lower leg

(

6,000 rarls over six weeks) in addition to an adjuvant

chemotherapy regimen consisting of vincristine,

dactinomy-cm, and cyclophosphamide.

She showed no clinical evidence of recurrence until March 1974 when headaches developed. A few days later she underwent an acute CNS episode in the outpatient clinic with the rapid onset of CNS irritability and coma. Neuro-logic signs were suggestive of a right intracranial lesion, and

an immediate CT brain scan showed a huge mass located in the posterior parietal area, principally on the right (Fig. 5). Cerebral angiography was also consistent with this finding. Several hours after her sudden deterioration a neurosurgical procedure was performed and a “small cell sarcoma compat-ible with rhabdomyosarcoma” was incompletely resected from her right paneto-occipital area. This was followed by cranial vault irradiation (5,200 rads over 36 days using a linear accelerator), during which time she received five intrathecal injections of methotrexate by lumbar punctures. The systemic chemotherapy regimen was continued, and she recovered completely from this episode. Headaches and a staggering gait became evident five months later. Neurologic

#{176}Emitronics, Inc., Northbrook, Illinois 60062.

FIG. 1. Schematic diagram showing the basic principle of the CT brain scanner. (Courtesy of the Cleveland Clinic

Quar-terly.)

signs again indicated a right-sided intracranial lesion. A CT brain scan showed a mass in her right parieto-occipital area, again confirmed by cerebral angiography. Although plain roentgenography of her pelvic bones was normal, both a radloisotopic 62gallium citrate scan and routine technetium Tc 99m diphosphonate bone scan showed activity in her left pelvis. She died three weeks later, after a left hemiparesis and then coma developed. Permission for an autopsy was refused.

A 17-year-old boy underwent a modified hemipelvectomy for an osteogenic sarcoma of the upper femur in March 1973. Despite adjuvant chemotherapy consisting of vincristine, adriamycin, cyclophosphamide, and phenylalanine mustard, pulmonary metastases developed nine months after the amputation. These metastases were treated with high-dose methotrexate infusions followed by “citrovorum factor rescue” and concomnitant radiotherapy (3,900 rads). The metastases cleared radiologically. Four months later head-ache, vomiting, and diplopia developed. Abnormal neuro-logic physical findings including papilledema indicated a lesion of the left cerebral cortex. A CT brain scan (Fig. 6) showed a large irregularly rounded area of decreased density

in the left posterior temporal and occipital regions shifting the ventricular systems to the right. A radioisotopic techne-tium Tc 99m brain scan also indicated an area of increased

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Fmc. 2. A, A standard netmroamiatomical horizontal cross-section through the brain. B, CT scan

abotmt the same level in which internal structures such as the cortex, ventricles, and choroid plexuses can be differentiated.

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FIG. 4. CT brain scan of patient 1 showing right frontal lobe FIG. 5. CT brain scan of patient 2 showing a large mass in the

metastasis. right posterior parietal area.

regimnen was continued. There was some clinical improve-ment in his neurologic symptoms and signs, and a repeat CT brain scan two months later in June 1974 showed the cerebral IflS5 had partially regressed. However, he died on the day of the repeat scan with a recurrence of pulmonary metastases and a massive pleural effusion. Postmortem examination confirmed the presence of widespread metas-tases including a left posterior temporal metastasis.

DISCUSSION

These cases indicate the remarkable capacity of

CT to demonstrate the presence of intracranial

lesions without danger or discomfort to the

patient.

The

presence

of the

metastasis

in case

1

was determined during an outpatient visit, and

this

was

the

principal

factor

in

deciding

to

withhold

all

further

active

therapy.

The

advan-tage of CT over standard radioisotopic techniques

is obvious

by the

results

of two

studies

done

at the

same time

(Fig.

6 and

7).

In a 22-year review of autopsy experience at

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Fm;. 7. Standard posterior view radioisotopic l)raiml scami of the samiie lesiomi sliowmi in Figure 6.

Memorial Sloan-Kettering Cancer Center only 13 of 231 brains examined from children with solid tumors

had

cerebral

metastases.

In

that

series

neuroblastoma, embryonal rhabdomyosarcoma,

and

\Vilms’

tumor

were

the

common types of

malignant

disease

with

this

complication,

although one child had hepatocellular carcinoma

and one

child

had

osteogemc sarcoma.

Thus,

the

diagnoses in our patients (rhabdomyosarcoma, osteogenic sarcoma, and hepatocellular carci-noma) are consistent with this previous report. In the Memorial Sloan-Kettering series all of their

patients had pulmonary metastases prior to the onset of CNS symptoms; this was true for two of our patients. Our patients had neurologic mani-festations commonly encountered in patients with intracranial tumors, i.e.,

headaches,

vomiting, seizures,

and

heniiparesis.

The treatment of these unfortunate children is

unsatisfactory.

All

of

these

children

with

intra-cranial

metastases

seen

here

during

this

period

were dead within six months of detection. Two of

these three children received whole-brain

irradia-tion

with

symptomatic

improvement

in

each

case; however, dexamethasone was also given concomitantly. Deutsch et a!.4 have also reported that total-brain radiotherapy iii adults with brain metastases usually provided some relief of

symp-toms.

In pediatric medicine CT brain scans have already been found to be useful in detecting primary

and

metastatic

brain

tumors, hydroceph-alus, orbital tumors, cerebral abscess, subdural

and

epidural

hematomata,

infarcts

or

hemor-rhages, porencephalic cysts, and focal and diffuse

cerebral

atrophy.

We

also

use

this

technique

as

part of our routine metastatic evaluation of a child with a newly diagnosed malignancy. The usefulness of the CT brain scan is enhanced by its noninvasive nature, but its principal difficulty in pediatric practice is its requirement of 20 minutes

of nonmovement requiring significant amounts of sedation. Radiation dosage is less than that of a

skull

roentgenographic

series.

We

frequently

use

it as a procedure which precedes a carotid angio-gram during a diagnostic evaluation, and its use has decreased considerably the need for

pneu-moencephalograms and standard radioisotopic

brain

scans.

Our experience with children confirms the

experience

of others

with

adults

that

this

tech-nique

would

help

in the evaluation of the patient

with

intracranial

disease

of any

etiology.

Without

the risks of carotid angiography or pneumoen-cephalography, the CT brain scanner will become a major neuroradiologic tool. The Cleveland

Clinic is presently evaluating a total-body CT scanner, and our preliminary experience has been such that we can predict that this new diagnostic tool will be helpful in the diagnosis of intraspinal, thoracic, and abdominal lesions.

SUMMARY

Three

children

with

malignant disease have

had

intracranial

metastases

demonstrated

by

CT

scan. This highly complex roentgenographic tech-nique should prove to be of considerable help in the evaluation of children with nialignancies. It is safe, painless, highly accurate, and can be used on

an outpatient basis. It appears to be more precise in localizing lesions than radioisotopic brain

scan-ning techniques.

REFERENCES

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2. Vannucci RC, Baten M: Cerebral metastatic disease in childhood. Neurology 24:981, 1974.

3. Hounsfield GN: Computerized transverse axial scanning (tomography): I. Description of system. Br

J

Radiol 46:1016, 1973.

4. Deutsch M, Parsons JA, Mercado R Jr: Radiotherapy for intracranial metastases. Cancer 34: 1607, 1974. 5. Houser OW, Smith JB, Gomez MR. et al: Evaluation of

intracranial disorders in children by computerized axial tomography: A preliminary report. Neurology 25:607, 1975.

6. Amnbrose

J:

Computerized transverse axial scanning (tomography): II. Clinical application. Br J Radiol

46:1023, 1973.

7. Baker HL Jr, Campbell JK, Houser

OW,

et a!: Comfiputer

assisted tomography of the head; an early evalua-tion. Mayo Clin Proc 49:17, 1974.

8. Zelch JV, Duchesneau PM, Meaney TF, et al: The EsiI scanner and its application to clinical diagnosis. Cleve Clin

Q

41:79, 1974.

9. Weinstein MA, Rothner AD, Duchesneau, PM, em’ al:

Computerized tomography in diasteniatomyelia. Radiology 117:609, 1975.

10. Dylnent PC, Haaga JR, Alfidi RJ: Total body scanning by computed tomography in pediatric oncology: A

preliminary report. Unpublished data.

IMMORTALITY

If medicine aims at death prevention, rather than at health, then the medical ideal, ever more

closely to be approximated, must be bodily immortality. Strange as it may sound, this goal really is implied in the way we as a community evaluate medical progress and medical needs. We go after the diseases that are the leading causes of death, rather than the leading causes of ill health. We evaluate medical progress, and compare miiedicine in different nations, in terms of mortality

statistics. We ignore the fact that for the most part we are merely changing one set of fatal

illnesses or conditions for amiother, and not necessarily for milder or more tolerable ones.

I am not suggesting that we cease investigating the causes of these diseases. On the contrary, medicine should be interested in preventing these diseases, or failing that, in restoring their victims to as healthy a condition as possible. But it is primarily because they are causes of unhealth, and only secondarily because they are killers, that we should be interested in

preventimig or comnbating themrm.

LEON R. KASS

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1976;58;72

Pediatrics

Paul G. Dyment, A. David Rothner, Paul M. Duchesneau and Meredith A. Weinstein

Computerized Tomography in the Detection of Intracranial Metastases in Children

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