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1167

Letters ..-...

,

Radiology

in East

.

.

. .

.

::

-

,c,

.

. ‘.

::

‘

practical

Africa

experience before they start the radiology program. They 2 years of training at Kilimanjaro Christian Medical Center in interpreting radiographs and performing radiologic procedures, including sonography. will receive

As members of the East African Medical Assistance Minneapolis-based

organization

that

since

i 987

Foundation,

has

been

a

raising

money to improve radiologic care in Tanzania, we read with great interest the letter [i] by Mark Baker and Frederick Porter on their experience at Muhimbili We applaud their efforts

community

regarding

in the third

world.

our experience

Medical Center in Dar es Salaam, at raising the consciousness ofthe

the complex

Although

indicates

care

need

Our conclusions

Several

are based on the

Helmut Diefenthal and University of Minnesota

who has now spent 9 years in Tanzania,

Kevin chest

including 5 years

as a radiologist at Kilimanjaro Christian Medical Center in Moshi, Tanzania, where he performs a full range of radiologic studies. One of our board members, Kevin Gustafson, a radiologist from Minneapolis, visited Dr. Diefenthal in Tanzania in November 1 990 and

worked

with him for 2 weeks.

We have found that donating used, older equipment is generally a waste of time and effort. Even if the equipment arrives safely, installation is a logistic nightmare. If by chance it is installed in working

condition,

the first time a problem develops

last time the equipment

parts for most

is used.

Service

used radiologic

equipment

that

is new,

far, the radiographic

dependable,

equipment

with the equipment is almost

equipment

Africa is littered with well-intentioned The first thing that all of Africa

that is relatively dependable, widely applicable to many clinical needs, and portable. Two other tremendous advantages are that it does not

with many of their conclusions, different needs for donated equip-

of two of our members, Dr. Diefenthal is a retired

radiologist

in radiologic

we agree

slightly

ment than their letter indicates. experience Gustafson.

issues involved

Tanzania. radiologic

Dr. Diefenthal and the East African Medical Assistance Foundation have found that sonography is in many ways the imaging technique of choice in East Africa. It is a way of doing cross-sectional imaging

is the

nonexistent,

and

are unobtainable.

East

white elephants. needs is good basic radiographic affordable,

companies

and

repairable.

have entirely

ignored

to be installed

is an inexpensive companies

service is available. large. Currently,

and does not require

film. Again,

and rugged unit in the $20,000 have machines

The potential

Dr. Diefenthal

market in the developing

Christian

in a developing country, for the reasons stated. Any further questions about our organization can be addressed to John Knoedler (61 2-3472008) or Kevin

Gustafson

(61 2-924-5i

70).

Thus

this William University

thing that is badly needed

of Minnesota

is an appropriately

have had 5 years of formal medical training and a number of years of

Clinic 55455

Minneapolis,

MN

Helmut Diefenthal Kilimanjaro

Christian

Medical Moshi,

Center Tanzania

John P. Knoedler Hennepin

educated

of Tanzania to organize a school in radiology. Although not M.D.s, as physicians, and students will

and MN

Kevin D. Gustafson

County

group of health care practitioners that can serve the radiologic needs of the country. Dr. Diefenthal and his associate, A. P. S. Lyimo, have been requested by the Government to train assistant medical officers assistant medical officers function

M. Thompson

Hospital

Minneapolis,

hospitals are well smaller hospitals.

Each of the facilities could use a basic, dependable radiographic unit, which, in our estimation, should cost approximately $30,000$40,000. The World Health Organization has endorsed a radiographic system that supposedly fulfills this need, but the price of the system is approximately $60,000, which is too expensive for Africa. The second

world is

physicians and assistant medical officers to use sonography. The Center hosted an international conference, Ultrasound in Africa, in October and November 1991. We agree with the comments of Drs. Baker and Porter on the need for basic radiographic accessory items, and we encourage readers to donate these through the system that has been arranged at Duke University. It has been our sad experience, however, that despite being extremely well intended, the donation of older, discarded equipment from the United States generally ends up unused

falsely concluding that it would not be profitable. Tanzania alone has 23 million people, and as Drs. Baker and Porter correctly and 25 regional has many other

range.

30 to 35 sonographic examinaMedical Center and is training

need,

pointed out, the referral hospitals organized. In addition, Tanzania

is needed

that may fill this bill, if adequate

performs

tions per day at Kilimanjaro

what

to $30,000

Medical

Center

Minneapolis,

MN

Medical

Center,

REFERENCE 1 . Baker ME, Porter FR. A report on radiology at Muhimbili Dar es Salaam, Tanzania (letter). AJR i992;157:195

LETTERS

1168

Bochdalek’s

Reply

We thank

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their

AJR:i58,

Drs. Thompson,

helpful

and

Diefenthal,

insightful

letter,

and

Gustafson, for

their

and Knoedler

interest

in the

for

health

care needs of Tanzania. We applaud their efforts in improving the radiologic care in that country and are quite pleased with what they have already accomplished. In September i 991 , we had the opportunity and pleasure of hosting in our department the new head of radiology at Muhimbili Medical Center, R. Kazema. We agree that most equipment donated to

countries parts

like Tanzania

and service.

is wasted

But, certain

because of the lack of appropriate

equipment

is not. In fact, most

of the

Hernia:

A 53-year-old

a right-sided were

woman

mastectomy

equivocal

showed

ageal mesentery

especially

in a third-world

service.

Clearly,

service

for

country,

equipment

the

(used

specific

should brand

or new)

is a lack never

in any

country,

of consistent

be sent

of equipment

and

and reliable

to a country

where

is unavailable.

Perhaps

some of the problems Thompson et al. have encountered with donated equipment are related to this issue. Service has been avail-

able for much of the donated point, has kept the equipment is a national/international equipment. If a consortium donated equipment, then

equipment

could determine

and where

it would

equipment at Muhimbili and, up to this running. In our opinion, what is needed

coordinated effort focused on donated were formed to coordinate an effort for hospitals and clinics with older medical

whether

be most

this equipment

would be useful

effective.

We agree with the Minneapolis

group

that the basic radiologic

system endorsed by the World Health Organization and sonographic equipment would be extremely helpful means of providing essential radiologic care. Unfortunately, as Thompson et al. indicated, Tanzania, as well as many other countries, does not have the hard currency necessary for even one unit. Therefore, in lieu of new units, usable,

serviceable, key to this

a follow-up

necessitated

chest

radiograph

1 year

after

by breast cancer. The findings

metastatic

disease

of the lungs.

CT

parenchyma window settings, the abnormality looked like a metastatic tumor (Fig. 1 A). At mediastinal window settings, it was clear that the mass was herniated retroperitoneal fat (-1 20 H) (Fig. i B). Scans at lower levels showed a defect in the diaphragm through which retroperitoneal fat herniated (Fig. 1 C). Several potential routes exist for protrusion of fat or other abdominal contents through the diaphragm. The foramen of Bochdalek is a developmental defect in the diaphragm posteriorly produced by failure

of the retroperitoneal

equipment

had

but suggested

problem

any

CT Findings

a round lesion 2 x 2 cm at the base of the left lung. At lung

functioning equipment at Muhimbili is donated. The problem now is that it is so old that in many respects it is no longer serviceable. As our colleagues from Minnesota have pointed out, the major with

May 1992

canal membrane to fuse with the dorsal esophwall. The foramen of Morgagni, on the other hand, is an anterior diaphragmatic defect of developmental origin

resulting

sternum

and the body

from

between

incomplete

attachment

the septum

of the

transversum

diaphragm

to the

and the right and left

costal origins of the diaphragm [i]. Hernias through the foramen of Bochdalek are the most common diaphragmatic hernias in infants; they are uncommon in adults. About

90% of Bochdalek’s hernias occur in the left hemidiaphragm because of the protective effect of liver on the right side. Small Bochdalek’s hernias

usually

contain

retroperitoneal

fat, kidney,

or spleen;

larger

ones contain jejunum, ileum, or colon. Morgagni’s hernia is the least common diaphragmatic hernia. It occurs in the right hemidiaphragm in more than 90% of cases, because of the protective effect of pericardium on the left side. Small Morgagni’s hernias contain omentum, usually with an extension of the peritoneal sac; larger ones contain

liver,

stomach,

small

intestine,

or transverse

In adults, Bochdalek’s and Morgagni’s hernias and asymptomatic [i , 2]. In our case, demonstration

colon

[i

,

are usually of the

2]. small

defect

in

donated equipment seems to be the only alternative. The is to appropriately match the equipment with the

process

region.

We also agree that an appropriately practitioners

is necessary

has few physicians medical

would

officers

in a country

educated group of health care such as Tanzania. Tanzania

and even fewer radiologists.

in radiology

relieve the already

would

provide

overworked

radiologists

burden of film interpretation. Last, we are thankful for the letter from because it will help raise the consciousness radiologic

community.

We

are

pleased

Training

an essential

with

education, perspective

Medical

and-we on the

strongly recommend Zurich, Switzerland.

Center.

the

group’s

change

of radiology

a recent

efforts,

In fact, we

com-

will and staff members By this exchange, understanding,

hope-tangible problem

and

of some of the

the Minneapolis group of the international

mitment, and monetary and physical support. soon begin an exchange program of residents with the Muhimbili

assistant

service

overview

will

occur.

in developing

[1 ] written

For

by Dr. Fuchs

University

Muhimbii

we from

E. Baker Eric Porter

Medical

Durham,

Dar

further

countries,

Mark Duke

too,

Center

NC 27710 R. Kazema

Medical

es Salaam,

Center Tanzania

REFERENCE 1 . Fuchs WA. 906-909

Radiology

in developing

countries.

Invest

Radiol

1991;1 0:

Fig. 1.-Bochdalek’s

hernia

in

a 53-year-old woman 1 year after surgery for breast cancer. A, CT scan at lung window setting shows a round mass 2 x 2 cm at left lung base. B, CT scan

at mediastinal

win-

dow setting shows mass, which consists

of fat (-120

posterior

to spleen.

H), is just

C, CT scan at level lower than B cleariy shows diaphragmatic defect of Bochdalek, through which mass of retroperitoneal fat has herniated.

LETTERS

AJR:158, May 1992

the left hemidiaphragm hernia.

established

the diagnosis

of a Bochdalek’s

Controlled women

Ziya Kumcuoglu R. Nun Sener Hospital

of Ege

Bornova,

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1169

University

lzmir,

Turkey

REFERENCES

screening been

trials of screening

40-49

years

procedure)

a driving

have

the mortality

intervals

rates

The letters

by Hall, Potchen, and Edelstein [1] in the October i99i are reminiscent of the fable of the blind men and the elephant. Each man describes what he feels. What each describes is correct for what he feels, but none describes the animal in question. Consider the following: (1) Screening mammography as currently propounded in the United States and the controlled trials to date are intended to reduce the mortality from breast cancer in the population. issue

of the AJR

(2) The

positive

predictive

value

(PPV)

is calculated

as follows:

interval

delays

and reduces

tool

is used.

slower

As

growing

the

population

cancers

occur,

grows

younger

women

older,

and the texture is not

and where PPV has women

screened

the magnitude

are

of any

a greater

number

of the breasts

and diagnosis

easy.

Although

of

is such

is greater. I happen

to think

such screening can be done and done effectively, making a high PPV the penultimate achievement is counterproductive. Clinical examination and breast self-examination are necessary to keep the falsenegative penalty effect to a minimum. In some situations, 5-mm cancers and ductal nation alone.

carcinoma

in situ can be found

by clinical

exami-

Myron Moskowitz University

of Cincinnati Cincinnati,

PPV

number of true-positives (TP)/(number of TP + number of falsepositives [FP]). (3) Expert mammographers operate along the same receiver-operating-characteristic curve, with only minor deviations [2]. (4) The annual rate of breast cancer in the United States is as follows [3]: ages 40-49 years, 1 58/1 00,000; ages 50-59, 244/i 00,000; and ages 60-69, 365/i 00,000. (5) If we assume that the TP rate for

(i) For (no other

reduction in mortality but has little impact on excess mortality.) (2) For women more than 50 years old, screening will be at least as good as that in the Health Insurance Plan tests, whatever method or

Screening

and Malpractice

among

only

higher than among women not screened [4]. (Modeling shows this is easily explicable as a result of the false-negative reassurance effect [5]. The false-negative reassurance effect is maximized by either inappropriate screen threshold or poor quality imaging. Screening at

that the latitude for errors in detection

Mammography

the following:

mammography

at inappropriate

factor,

an inappropriate

1 . Gregson RHS. The mediastinum. In: Sutton D, ed. A textbook of radiology and imaging, 4th ed., vol. 1 . Edinburgh: Churchill-Livingstone, 1987: 368-391 2. Moss AA, Gamsu G, Genant HK. Computed tomography of the body. Philadelphia: Saunders, 1983:397-398

have shown

old who

Hospital OH

45267

=

is 85%

mammography

and the FP rate is i %,, the PPVs

ages will be as follows: ages 40-49, 207/i 207 = i 7%; and ages 60-69, can be changed mammographer panels of expert mograms

i 34/i 134 3i 0/i 3i 0

for these

ages 50-59, 24%. These PPVs i 2%;

= =

only (i) at the expense of the TP rate or (2) if the indeed has a power of interpretation beyond that of mammographers already tested on screening mam-

REFERENCES 1 . Hall FM, Potchen

EJ, Edelstein

G. Mammography

and malpractice

and replies). AJR 1991;1 57:883-885 2. Swets JA, Getty DJ, Pickett AM, et al. Enhancing and evaluating accuracy. In: Medical decision making. Philadelphia: Hanley

(letters diagnostic & Relfus.

1991:9-18

3. Ries LAG, Hankey BF, Miller BA, et al. Cancer statistics review 19731988 (NIH publication No. 91-2789). Washington, DC: National Cancer Institute, 1991 4. Stomper PC, Gelman AS. Mammography in asymptomatic and asymptomatic patients. Hematol Oncol Clin North Am 1989:3:611-640 5. Moskowitz M. Cancer (in press)

to date.

It is obvious

to a relatively

that diagnostic

populations,

high concentration

which

of cancer

have been

cases

distilled

either by self-

selection or previous screening, will have a higher PPV. The concentration of cancers in these populations is usually more than 2-3%. If the rate is 2% and the TP rate is 85% and the FP rate is 1 %, the

PPv will be 63% (1700/2700). Therefore,

it is sheer folly to talk about

PPVs as sacrosanct.

When

Reply

We are pleased

to respond

to the letter

of Dr. Moskowitz.

He

continues to pursue an area in which he has many publications. Much of what he responds to is not at issue and is not discussed in our article [i] or letter [2]. We understand that he is advocating less

PPVs are discussed, a rational assessment can be made only if we know the age distribution of all women having mammograms, the size of the examined population, if clinical examination was also done,

concern for “excessive” surgical biopsies because the primary purpose of screening mammography is to decrease deaths caused by breast cancer. In our opinion, it is not appropriate to ignore implica-

the incidence of breast cancer among all the women having mammograms, the age-specific distribution of all cancers occurring in the screened population whether at screening or within i year of a

tions of “excess”

screening specificity.

mammogram Sensitivity

operating-characteristic mograms

(as

suggested

that shows no cancer, and the sensitivity can be determined

by taking

analysis

of a screened

before),

or if sufficient

population numbers

are enrolled in the screening program (probably 30,000 estimate of sensitivity can be determined by evaluating

of interval cases. Unfortunately, women who examinations,

are screened and long-term

huge populations

and

part in a receiver-

of mamof women

or more), an the number

are needed. All the

should have had independent clinical follow-up of most of the women is

to provide meaningful data. Data derived from populations in the diagnostic range of incidence cannot be compared with data

surgical breast biopsies in the diagnosis

of nonpal-

pable breast cancer. The literature on compliance suggests that some women may not seek appropriate screening mammograms if the biopsy to cancer rate is “too high.” Diagnosis made on the basis of mammographic findings is imperfect. If a positive mammogram is defined as one that shows changes sufficient to warrant surgical biopsy for prospective nonpalpable cancer, then Moskowitz’s claim ofa i % false-positive rate is clearly erroneous. The ability to diagnose nonpalpable breast cancers can be increased without resorting to open surgical biopsy. When this happens, more women may accept

screening mammography. We advocate the Karolinska approach, which has been extremely successful. In the Karolinska program,

necessary

experienced

derived

and their interpretations are closely correlated with the clinical outcome. The major addition to Moskowitz’s strategy is stereotaxic fine-

from screening

populations.

mammographers

read

a large

number

of examinations,

1 170

LETTERS

aspiration

needle suspected

biopsy,

lesion

performed

with the patient

prone,

when

a

is detected.

The argument that positive predictive value should not be of concern runs counter to our experience, in both containing health care costs and diminishing “disease” induced by the current diagnos-

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tic system.

We completely

agree with Moskowitz

that the primary

intention is to decrease mortality from breast cancer, but we think that this will not be possible if some women do not obtain screening mammograms because of associated morbidity. Moskowitz’s caution about overemphasis of positive predictive value is a legitimate concern only if the effects of iatrogenic morbidity are ignored. We support Hall’s perception that the implications of false-positive findings on mammograms also are a legitimate concern.

E. James Potchen Arlene E. Sierra Michigan State University East Lansing, Ml 48824

A 52-year-old man had blunt injury to the abdomen. MR images were obtained with a 0.5-1 superconducting magnet i hr after the injury (Figs. iA-i C). The procedure took i 5 mm. At surgery, a 20cm-long hepatic laceration in the posterior segment of the right lobe of the liver was detected present in the peritoneal

and repaired. About 500 ml of blood was cavity. The patient recovered uneventfully. 2 months after surgery (Figs. i D-i F) showed

Follow-up MR imaging residual abnormality. In this case, MR imaging was a rapid and noninvasive

MR Imaging

of Hepatic

Laceration

We report a case of hepatic laceration useful

in assessing

in which MR imaging was

way to make

the diagnosis of an acute laceration of the liver. The procedure took no longer than a CT scan would have required, and contrast medium

was not needed hypointense

[1]. In the acute stage, the laceration

on Ti -weighted

images

weighted and proton density-weighted injury, the laceration was hyperintense

and was

was slightly

hyperintense

on T2-

images. Within i month of on all MR sequences. Fumio

Yamamoto

Yamamoto Hospital Imari 848, Japan Yonglin Pu

REFERENCES 1 . Potchen EJ, Bissei MA, Sierra AE, Potchen JE. Mammography and malpractice (commentary). AJR 1991;i56:475-480 2. HaIl FM, Potchen EJ, Edelstein G. Mammography and malpractice (letters and replies). AJR 1991;1 57:883-885

May 1992

AJA:158,

Beijing

Medical

University,

People’s

Hospital

Beijing, China REFERENCE

1 . Mirvis SE, Whitley NO, Vainwright JR, Gens DR. Blunt hepatic trauma in adults: CT-based classification and correlation with prognosis and treatment. Radiology 1989:171:27-32

the injury.

Retained

Barium

Treatment

Enema

Tip: Proposed Needle Puncture

Balloon

By Percutaneous

A recent issue of the AJR included a letter from Kesaria [i] about a balloon tip of a barium enema kit that would not deflate. The balloon

was

removed

by a surgeon,

presumably

by incising

the skin and

anal

mucosa. Coincidentally, in the next letter in the same issue, Hamed and Chezmar [2] wrote about using percutaneous puncture of a gastrostomy tube balloon to deflate the balloon and thus relieve an obstruction of the small bowel. It occurred to me that a nondeflatable balloon of a barium enema tip can be similarly dealt with. I propose that in that situation, local anesthesia and fluoroscopically guided puncture of the balloon with a 20- or 22-gauge spinal needle could be used. This would avoid a more invasive procedure to deflate the bulb and remove the tip. M. R. Ramakrishnan Lonesome Pine Hospital Big Stone Gap, VA 24219 REFERENCES 1 . Kesaria AC. Retained E-Z-EM balloon barium enema tip (letter). AIR 1991;157:885 2. Hamed AK II, Chezmar JL. Percutaneous needle puncture for treatment of ileal obstruction caused by migration of a gastrostomy tube (letter). AiR 1991;157:885-886

Reply

Fig. 1.-Laceration MR images

A-C,

in posterior segment obtained

of right lobe of liver. injury. Lesion (arrows) is hypoin(SE 625/25, A) and hyperintense on T2-

I hr after

tense on Ti-weighted image w&ghted (SE 1800/100, B) and proton density-weighted

(SE 1800/40,

C)

I appreciate the comments of Dr. Ramakrishnan. Both the surgeon and myself had attempted to puncture the balloon with a needle; however, we could not reach the inflated balloon. The surgeon then anesthetized the anal mucosa with a local anesthetic and pulled the inflated balloon out. The skin and anal mucosa were not incised.

images. 0-F,

MR images obtained 2 months after surgery. Lesion (arrows) is hyperintense on TI-weighted (SE 625/25, D), T2-weighted (SE 1800/100, -E), and proton density-weighted (SE 1800/40, F) images.

Ashwin C. Kesaria Firelands

Community Sandusky,

Hospital OH

44870

AJA:158,

Inadvertent Dimeglumine

IV Administration During Early

Gadopentetate

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for

MR

imaging.

We

of Gadopentetate Pregnancy

dimeglumine

is a commonly

To

of our

about its safety consequently not manufacturer has during pregnancy munication).

the

best

in pregnancy, and its recommended by the no data on file on the IV (J. Haustein, Schering

report

the

inadvertent

used IV contrast

knowledge,

nothing

agent

is known

use during pregnancy is manufacturer. So far the administration of this agent AG Berlin, personal com-

IV administration

of gadopen-

tetate dimeglumine to a patient who was pregnant. A 24-year-old woman with multiple sclerosis had been part of a monthly MR imaging protocol for 9 months. The protocol consisted of a precontrast long TA sequence, bolus injection of gadopentetate dimeglumine (0.2 mmol/kg), a flush with iO ml saline, and short TR sequences [i]. At the time of the 10th study, the patient was imaged according to the standard protocol. Later, it was learned that she had been pregnant at the time of the 10th study (first day of last menstruation was 23 days before the MR imaging). She had not been aware of her pregnancy at the time of imaging but reported it at the time of the next (11th) study. She subsequently had follow-up examinations

with

unenhanced

MR

imaging

only.

After

an

The

of

gestational

age

of

the

(pre-)

embryo

when

gadopentetate

which

could

the second

was

injected

have

occurred

and third

dimeglumine

during

was

approximately

with

exposure

months).

pregnancy,

in the organogenetic

Clinical

stage,

use of IV gadopentetate

however,

should

be

avoided

until

enough evidence is gathered about the effects of the agent on child development. The possibility of pregnancy should be excluded by means of a careful history before gadopentetate dimeglumine is injected IV. Inadvertent administration during pregnancy cannot always be avoided, as illustrated by our case. Our patient did not have early spontaneous abortion, and we have not seen any harmful effects to the child so far. Therefore, termination of a pregnancy solely because

the

dimeglumine

mother may

inadvertently not

was

injected

with

2

Fig. 1.-Sagittal

MR image of 63-year-old man with urachal tumor shows extending from bladder wall. Mass is continuous and umbilicus. UB = urinary bladder.

a mass (arrow) tapers

toward

Fig. 2.-Sagittal (arrowhead)

MR image of 55-year-old man with urachal tumor shows in anterosuperior part of bladder wall. Triangular bud is oriented in direction of urachal communicating ligament.

thickness,

an average of four signals, and a 1 60 x 192 matrix were

a mass (arrow)

used. The

9 days (blastula stage), and the (pre-) embryo was in the process of implantation. Formation of a placenta had not started, and small molecular substances like gadopentetate dimeglumine (550 d) could have freely diffused into the (pro-) embryo. The most likely adverse effect would have been an early spontaneous abortion (rather than congenital malformations, dimeglumine

1

uneventful

39 weeks, she delivered a healthy girl. The child is now 3 months old and is developing normally. pregnancy

1171

LETTERS

May 1992

gadopentetate

first

case

was

a 63-year-old

man

who

cm tumor mass

in the dome

2.6

x

cystectomy ligament, chal

3.4

cm

of the

bladder.

in the

dome

MR showed of

was done, with excision and

umbilicus.

Histologic

the

Roel

examination

MB Amsterdam,

the

showed

MR Findings

ical extension

in the

middle

line

show the shape of the tumor toward the umbilicus.

and

calcification.

Sagittal

and the urachal

MR

ura-

MR

ligament

images

extending

Hisatoshi Maeda Tsuneo Kinukawa Hajime

Kuhara

Ryouhei Hattori Touru

Hospital

Okazaki

Netherlands

in Urachal

MAI changes methylpred-

Carcinoma

Carcinoma of the urachus is difficult to distinguish from common bladder tumors [i-3]. The prognosis is considerably worse than that of primary bladder carcinoma, because urachal tumors have a predilection for local invasion, and the diagnosis often is made relatively late in the disease. Two patients with proved adenocarcinoma of the urachus had sagittal

tubular

Furukawa

Municipal Okazaki,

Hospital

Aichi,

Japan

REFERENCES

1 . Barkhof F, Hommes OR, Scheltens P, Valk J. Quantitative in gadolinium-DTPA enhancement after high-dose intravenous nisolone in multiple sclerosis. Neurology 1991 41 :1219-1221

preoperative

Radical

The diagnosis of urachal carcinoma is suggested when a mass is present in the dome of the bladder associated with mostly extraves-

R. Algra

REFERENCE

2).

communicating

J. J. Heijboer

University

gross

adenocarcinoma.

and colleagues 1007

(Fig.

of the urachus,

Barkhof

Paul Free

painless

a dumbbell-shaped

bladder

be justified. Frederik

had

hematuria. The results of excretory urography were normal. Cystoscopy showed a small, smooth mass in the dome of the bladder. MR showed a tubular, 3-cm mass in the middle line of the bladder dome (Fig. 1). Partial cystectomy was done. The diagnosis was tubular adenocarcinoma of the urachus. The second case was a 55-year-old man who had had intermittent gross hematuria for 5 years. Cystoscopy showed a broad-based 3-

MR images

imaging were

on a 0.5-T obtained.

system. A 25-cm

Ti -weighted field

of view,

(320/25) 5-mm

slice

1 . Sheldon CA, Clayman RV, Gonzalez A, Williams AD, Fraley EE. Malignant urachal lesions. J Urol 1984;13: 1-7 2. Lee SH, Kitchens HH, Kim BS. Adenocarcinoma of the urachus: CT features. J Comput Assist Tomogr 1990:14:232-235 3. Gurret JP, Ody B, Megevand M. Carcinoma of the urachus demonstrated by CT. Eur J Radiol 1987:7: 1 42-1 43

Large

Cloisons

In i986, claimed

was

Hulnick diagnostic

Simulating and Bosniak of duplex

Duplex

Kidneys

[1] described kidneys,

that

on CT

a CT finding is, kidneys

with

they two

collecting systems separated by a thick septum of cortical tissue [2]. As might be expected, CT scans through the upper and lower poles

LETTERS

1172

AJR:158,

May 1992

REFERENCES

Downloaded from www.ajronline.org by 200.59.57.87 on 11/13/15 from IP address 200.59.57.87. Copyright ARRS. For personal use only; all rights reserved

1 . Hulnick Comput

DH, Bosniak MA. “Faceless” kidney: Assist Tomogr 1986;1 0:771-772

CT sign of renal duplicity.

J

2. Glassberg KI, Braren V, Duckett JW, et al. Suggested terminology for duplex systems, ectopic ureters and ureteroceles. J Urol 1984:132:11531154 3. Hodson CJ, Mariani B. Large cloisons. AJR 1982:139:327-332 4. Keibel F, Mall FP. Manual of human embryology. Philadelphia: Lippincott, 1912:844-845

Avascular

Necrosis

in a Canine

Model

I just read the article by Brody et al. [1 ] on avascular necrosis in a model. I did not learn a thing, but I was upset and disturbed. Those poor beagles!!!!! I think academicians should find something else to do besides torturing innocent animals. I feel some animal experiments provide a greater good for humans. But a majorityincluding this one-don’t. Who gives a damn what avascular necrosis looks like on days 0, i , 7, and 23. If I see a hypointense smudge in the femoral head, I give a brief differential diagnosis. If I see a bright and dark ring, I say avascular necrosis. canine

Michael J. Eisenberg

Fig. 1.-Large cloisons simulating duplex kidneys. A, Excretory urogram shows long upper pole infundibula (straight arrows). Midzones are drained by calices (arrowheads) lying deep within kidneys, near renal pelves. Relatively large gaps are present between

upper and midzone infundibula,

mass (large cloison,

curved

Holladay

Park

Medical

Portland,

Center

OR 97232

occupied by large cloisons. An apparent

arrows)

displaces upper and lower pole infundibula on left. B, CT scan through left upper pole and right midzone shows calices and Infundibula surrounded by sinus fat (arrowheads) within left kidney but

none In right kidney, which has no renal sinus. C, CT scan through right lower pole and left midzone shows calices and infundibula surrounded by sinus fat (arrowheads) none In left kidney, which has no renal sinus.

within

right kidney

REFERENCE 1 . Brody AS, Strong M, Babikian G, Sweet DE, Seidel FG, Kuhn JP. Avascular necrosis: early MR imaging and histologic findings in a canine model. AJR 1991;157:341-345

but Reply

show calices and infundibula surrounded by sinus fat within the renal outline, whereas scans through the thick septum show renal parenchyma without calices, infundibula, or renal sinus [1]. Unduplicated kidneys, and the upper and lower poles of a duplex kidney, have thinner septa of cortical tissue, which Bertin called “cloisons” (French for septa), extending from the cortex to the renal sinus and separating the medulla into segments [3]. Hodson and Mariani [3] pointed out that cloisons had been mistranslated as “columns,” and they restored Bertin’s original term. In early fetal life, a large primary cranial cloison develops between the upper pole and the midzone, but in later fetal life, all cloisons are approximately the same size [4]. A large primary cranial cloison persists in duplex kidneys, and occasionally in unduplicated kidneys, as a congenital anomaly variously referred to as large cloisons, large septa of Bertin, or lobar dysmorphism. I saw a patient with bilateral large cloisons whose CT scans closely resembled scans of duplex kidneys.

urogram the upper and midzone infundibula showed renal parenchyma without calices, infundibula, or renal sinus on both sides, though at different levels (Figs. 1 B and 1C). The reason is clear enough: duplex kidneys look this way on CT because they have large cloisons. The characteristic findings, therefore, can occur in a kidney with large cloisons, with or without duplication. Gerald W. Friedland A

42-year-old

man had gross

hematuria.

An excretory

showed bilaterallarge cloisons (Fig. 1A). CT scans

Veterans

between

Affairs Palo

Medical Alto,

Center CA 94304

Today, we have no treatment for avascular necrosis. It is perhaps understandable, therefore, that the appearance of the earliest changes of this disease could be considered of academic interest only. My coauthors and I hope that in the future when avascular necrosis is detected during its early stages, treatment will be started immediately, and bone destruction will be prevented. Knowledge of the MR imaging appearance of the early stages will then be critically important.

With

the

goal

of bringing

this

time

closer,

we

performed

our investigation [i]. We surgically devascularized the distal femur of adult beagle dogs and did postoperative MR imaging and histologic studies. Using this model, we found that MR imaging can show changes in bone marrow as soon as 1 week after the onset of avascular necrosis. MR imaging showed a progression of increasing areas of low signal; the histologic findings during this time were diverse. One goal of our research was to see if MR imaging could detect avascular necrosis in its earliest stages, when treatment would likely be most effective. A second goal was to examine the histologic changes of the early stages in order to develop MR imaging strategies and to look for histologic insights that would suggest therapies for avascular necrosis. The cellular infiltrate that we observed may provide such an insight. Host response as well as the biomechanics of the marrow space may be responsible for bone destruction. The study was approved by our Laboratory Animal Care Committee. We took great care to minimize the animals’ pain. We were very aware of the appropriate concerns that surround research that involves animals. This investigation was discussed openly at our center so that our coworkers could understand our goals and the reasons for doing this work. Only the future will reveal the true value of this

AJR:158,

research. human

We feel that the potential

suffering

are

sufficient

to justify

benefits this

in the prevention

of

investigation.

Alan S. Brody Children’s

State University

Hospital

of Buffalo

of New York at Buffalo, School of Medicine Buffalo,

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1173

LETTERS

May 1992

NY

14222

to be i5#{176} of external rotation, although others have found that 20#{176} is best [3]. For patients of markedly different sizes, other leg-support pieces could be constructed. Thus, all patients can be accommodated by making a few adjustments to a single device. The device has been in use for several years at our institution, and it has

improved

the

quality

of

our

MR

studies

of

the

knee.

The

provision for accurate knee rotation and stabilization of motion results in reliable, high-quality studies that benefit both the physician and the

REFERENCE 1 . Brody AS, Strong M, Babikian G, Sweet DE, Seidel necrosis: early MR imaging and histologic findings 199i;157:341 -345

FG, Kuhn JP. Avascular in a canine model. AJR

patient.

If accurate

nor cruciate

positioning

is achieved

and

maintained,

the

ante-

ligament can be more reliably defined. Spencer

B. Gay

Norman C. Chen James R. Brookeman

A Device for Rotation During MR Imaging

and Stabilization

of the Knee

and colleagues University

of Virginia

Health

Sciences

Charlottesville,

We describe a simple device that we have developed to support the patient’s lower leg during MR imaging of the knee. It allows accurate and reproducible positioning of the knee in external rotation so that the anterior cruciate ligament can be best imaged. The device is constructed of Plexiglas and plastic, it has no metallic parts to cause artifacts during imaging. It consists of three separate pieces (Fig. i). The first is a Plexiglas base that anchors the device on the imaging table and serves as the point of attachment for the rest of the device. The second part is a block that serves as a link between the leg-support piece and the Plexiglas frame. The third piece

holds

the

patient’s

leg in place

in full extension.

It consists

of a

plastic sheet molded to fit the shape of a leg and three Velcro straps for securing the leg in place. The stabilization device is easy to use and takes little time to set up. It is assembled and seated in place on the imaging table with the knee coil. The patient is placed supine on the table. The patient’s leg is then strapped onto the leg-support piece and rotated externally to the desired angle, and the bolt is tightened to secure the position. The patient can relax throughout the examination and does not have to be concerned about maintaining the position of the leg. The additional time required for positioning is negligible and does not affect patient throughput. The device allows optimal display of the anterior cruciate ligament by minimizing motion artifacts while providing a measured degree of external rotation that can be reproduced accurately with each knee study. The leg piece holds the leg snugly at the foot, ankle, and knee such that the entire lower extremity moves as a unit. Rotation of the leg piece therefore reflects the same degree of rotation of the knee. The leg is secured in full extension, the position where the anterior cruciate ligament is maximally taut and imaging is therefore optimal. The device is constructed so that the axis of rotation passes approximately through the center of the knee. This ensures that changing rotation will not move the knee out of the center of the imaging field. Adjustments are easy. Degree of rotation is changed simply by rotating the leg and tightening a bolt. Most radiologists think that placing the knee in external rotation during MR imaging improves the study by including the entire anterior cruciate ligament in the image plane [i 2]. At our institution, the optimal angle of the knee appears

Center VA

22908

REFERENCES 1 . Mink JH. The ligaments of the knee. In: Magnetic resonance imaging of the knee. New York: Raven, 1987:93-112 2. King CL, Hinkelman RM, Poon PY, Rubenstein J. Magnetic resonance imaging of the normal knee. J Comput Assist Tomogr 1984:8:1147-1154 3. Reicher MA, Rauschning W, Gold RH, Bassett LW, Lufkin RB, Glen W Jr. High-resolution magnetic resonance imaging of the knee joint: normal anatomy. AJR 1985:145:895-902

Fournier’s Gangrene: MR Findings Fournier’s the scrotum wall.

We

Diagnosis

Based

on

gangrene is a fulminant, rapidly progressing infection of that also involves the perineum, penis, and abdominal

present

a case

of Fournier’s

gangrene

that

was

diagnosed

on the basis of MR findings. A 7i -year-old

examination sis.

Plain

diabetic

showed

radiographs

man

had

scrotal

scrotal swelling of the

pelvis

pain

and

and erythema

showed

swelling.

Physical

with skin necro-

subcutaneous

scrotum. Spin-echo MR images (i .5-T system) showed ening by gas of the scrotal skin and fluid lying between the dartos muscle (Fig. i ). The dartos muscle was thickened line of low signal intensity on T2-weighted fluid collection had high signal intensity on T2-weighted

gas

in the

marked thickthe skin and visible as a images. The images and

,

Fig. 1.-Knee stabilization device in place on MR imaging table. Patient’s leg is secured onto leg piece (short straight arrows) joined by nylon block (curved arrow) to Plexiglas frame (long straight arrows). Frame has two

supports that fit onto table of imager and a vertical piece for attachment of leg apparatus.

Fig. 1.-A and B, Fournier’s gangrene. Ti-weighted(A)and T2-weighted (B) MR images show marked gaseous thickening of scrotal skin and a fluid collection (arrowheads) between skin and dartos muscle. Muscle appears as a thickened line of low signal intensity (straight arrow) on T2weighted image (B). Left testis (curved arrows) has normal high signal intensity on T2-weighted image and was considered to have normal function.

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slightly

high

signal

intensity

on Ti -weighted

images.

Both

testes

and

epididymides had normally high signal intensity on T2-weighted images. The penis, including the corpora cavernosa and corpus spongiosum, also had homogeneously high signal intensity on T2-weighted images. The transition zone of the prostate was enlarged, but no areas of abnormal signal intensity were seen in the peripheral or transition zones on T2-weighted images. Sonograms could not be obtained because of the skin necrosis. Debridement was performed, and 3 weeks later, the patient had recovered fully. Fournier’s gangrene was originally described as a fulminating disease of unknown origin that devastated the genitalia of young male subjects. However, the disease may affect both healthy young males and elderly men, especially those who have diabetes, advanced liver or kidney disease, or immunosuppression [1 -3]. The gangrene commonly develops as a periurethral or perianal infection. Sometimes the point of origin is obscure, possibly a minute scrotal abrasion. The soft-tissue infection usually begins as an area of cellulitis adjacent to the portal of entry of the causative organism. The infection then begins to involve the deep fascia and spreads beyond the entry point. As fascitis develops, the overlying skin becomes involved [i -3]. The cause of the gangrene in our patient is not certain. However, a combination of two mechanisms may have been responsible for its development, as he had diabetes and had been massaging his scrotum

AJR:158,

LETTERS

1174

for 1 month.

Foumier’s gangrene causes marked thickening of the scrotal skin and, most importantly, air in the subcutaneous tissues. However, it can be confused with epididymitis, orchitis, and scrotal cellulitis [i, 2]. Therefore,

evaluation

of the testes,

epididymides,

and

scrotum

is

essential for making the correct diagnosis of this condition. The mortality rate is still significant. Early aggressive antibiotic therapy with debridement of all necrotic tissue is important, and further debridement must be done when indicated [i -3]. Knowledge of the extent of the necrosis is necessary when surgery is required. In our case, MR images showed marked thickening of the scrotal skin, extensive subcutaneous gas, and fluid accumulation. Both testes, the epididymides, the penis, and the abdominal wall were normal. Because the gangrene was confined to the scrotum, we decided that debndement was the only treatment needed. Thickening of scrotal skin and air in the subcutaneous tissues can be shown by sonography also [4]. Both sonography and MR are highly accurate for assessment of testicular lesions. However, MR is more useful than sonography; it allows a wider field of view, and it can be used in patients who have advanced skin necrosis. MR also can show extension of disease to the perineum, abdominal wall, and buttocks more accurately than sonography can. Sonography should continue to be the primary imaging technique for the diagnosis of Foumier’s gangrene. However, MR should be used in patients who may have spread of gangrene beyond the scrotum or who have advanced skin lesions. Hiromi Okizuka Kazuro Sugimura Takeshi Yoshizako and colleagues Shimane Medical University Izumo, 693, Japan

4. Begley

MG,

Fournier 387-389

Shawker

diagnosis

CN,

with

Percutaneous Transluminal Subclavian Arteries I

Bock

sacral

SN, Wei JP, Lotze

US.

Radiology

Angioplasty

MT.

1988:169:

of the

read with interest the article by Hebrang et al. [i] on percutaneous

transluminal

angioplasty

of the

subclavian

arteries.

In the introduction,

the authors state that they will report technical success, complications, and long-term follow-up of percutaneous transluminal angioplasty in a series of 52 patients. Despite this promise, I was unable to clearly determine the prevalence of complications. In discussing the subgroup of patients who required inflation of the balloon across the vertebral artery, the authors report that their results were “similar” to those of Vitek [2]. Does this mean that they had no complications? What about when the balloon was inflated proximal to the vertebral artery? Also, in discussing heparinization, the authors state that “no differences in complication rates were observed between patients treated with heparin and those not treated with it.” What, then, was the complication rate? Karen T. Brown St. Luke’s/Roosevelt Hospital Center New York, NY 10019 REFERENCES 1 . Hebrang

A, Maskovic

J, Tomac

B. Percutaneous

transluminal

of the subclavian arteries: long-term results 1991;156:1091-1094 2. Vitek JJ. Subclavian artery angioplasty and origin Radiology 1989:170:407-409

in

52

angioplasty patients.

AiR

of the vertebral

artery.

Reply Dr. Brown

on [iJ had no data on the prevalence of complications. In the first version of the manuscript, such data were included in table form (Table i). The editor asked us to delete the data because the complications and side effects associated with percutaneous transluminal angioplasty of the subclavian arteries are well known. Consequently, in the final draft of the article, we mentioned only that we did not have serious complications. A. Hebrang percutaneous

writes

that the article

transluminal

angioplasty

by me and my colleagues of the

Clinical

subclavian

Hospital

“Dr.

arteries

0.

Novosel”

41000 Zagreb,

TABLE

1: Side Effects

Percutaneous Patients

and Complications

Angioplasty

Associated

of the Subclavian

Treated wi Heparin

th

Total

Yes

No

Transient pain Groin hematoma Distal ischemia

6 i 0

4 0 i

Headache

0

1

i

Tremor

2

2

4

9

8

i7

Total

Croatia

with

Arteries in 52

Patients

Side Effects and Complications

REFERENCES 1 . Jones RB, Hirschmann JV, Brown GS, Tremann JA. Foumier’s syndrome: necrotizing subcutaneous infection of the male genitalia. J Urol 1979:122:279-282 2. Banks DW, O’Brien DP Ill, Amerson JR, Hester TA Jr. Gracli’s musculocutaneous flap scrotal reconstruction after Foumier’s gangrene. Urology 1986;29:582-585 3. Spimak JP, Aesnick Ml, Hampel N, Perskey L. Foumier’s gangrene: report of 20 patients. J Urol 1984;131 :289-291

TH, Robertson

gangrene:

May 1992

10 1 i

AJA:158,

Reply

REFERENCE 1 . Hebrang

A, Maskovic

J, Tomac

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of the subclavian arteries: 1991;156: 1091 -1 094

A Theoretical Frontal Horns

B. Percutaneous long-term

transluminal

results

in

52

Explanation of Asymmetry of the Lateral Ventricles

angioplasty patients.

AIR

of the

A familiar occasional finding on CT scans and MR images of the brain is the asymmetric appearance of the frontal horns of the lateral ventricles in healthy subjects. In Figure i , the septum pellucidum is seen just left of the midline, and that is why the frontal horns appear asymmetric.

This

situation

reminds

me of the

“cavum

septi

pellucidi.”

This is a potential space located between the two nonfused leaves of the septum pellucidum and is regularly present in the developing fetus. It begins to involutejust before birth in order to fuse completely at exactly the midline to form a single leaf of septum pellucidum. It reportedly persists throughout life in 5-i 5% of the population [i -3]. In Figure i if an arbitrary line is drawn just right of the midline, as a mirror image of the present (left) septum pellucidum, the result would be an imaginary cavum septi pellucidi within two (left and right) leaves ,

of the

septum

pellucidum.

This concept suggests that the asymmetry of the frontal horns reflects a developmental disorder. If one of the two leaves of the septum pellucidum is congenitally absent, then a normally expected “midline

fusion”

will

not

take

place

(because

only

one

leaf

would

be

present). The single leaf that is present, located off the midline, would create an apparent asymmetry of the frontal horns, as shown in Figure i . In addition, the posterior extension of the cavum septi pellucidi, when present, is termed a cavum vergae and is located between the bodies of the lateral ventricles [1 -3]. Another familiar but rare finding on CT scans and MR images in healthy subjects, an asymmetry of the bodies of the lateral ventricles, can represent a similar

event

with

the cavum

vergae

and

can

be caused

by the

same

mechanism discussed before. I think that asymmetric frontal horns or bodies of the lateral ventricles represent maldevelopment of the septum pellucidum in otherwise healthy subjects. R. Nun Hospital Bornova

Fig. scan

1175

LETTERS

May 1992

1.-Contrast-enhanced in healthy 21-year-old

of Ege

35100,

Sener

University

lzmir,

Turkey

Asymmetric appearance of the lateral ventricles, particularly of the frontal horns, as described by Dr. Sener, has intrigued us also. This appearance simulates unilateral obstructive hydrocephalus and may suggest an obstructive lesion at the foramen of Monro. In more than one instance at our institution, patients have had surgery because of a presumed foraminal lesion (Fig. 1), but no obstructive lesion has been found. (Incidentally, both septal leaves were present.) Curiosity about this asymmetry stimulated us to review the normal position of the septum pellucidum in an effort to explain this appearance. We reviewed the coronal Ti-weighted (600/20 [TRITE], 3-mm slice thickness) MR images of 57 otherwise healthy patients who were having MR for evaluation of abnormalities of the hypothalamic-pituitary axis. The septum was deviated in i 7 patients (to the right in i 2 and to the left in five). The average deviation from midline was 2.00 mm (range, 1 -7 mm). A cavum septi pellucidi was present anteriorly and superiorly in 20 patients, and, in most patients with septal deviation, both septal leaves were detected on the coronal MR image. We also evaluated the size of the temporal horns of the lateral ventricles. Our hypothesis was that the temporal horn would be dilated in those patients with obstructive unilateral hydrocephalus and not in patients without this disorder. The temporal horn was asymmetric in only four patients with septal deviation. In none of these were the temporal horns sufficiently dilated to suggest hydrocephalus. However, a review of the images of six patients with unilateral obstructive hydrocephalus showed obstructing lesions at the foramen of Monro, with contralateral septal deviation and associated dilatation of the lateral ventricle, including marked dilatation of the temporal horn of the lateral ventricle. Pathologic examples of septal deviation and asymmetric enlargement of the frontal horns (Fig. 2) show asymmetric dilatation of the frontal

horn

and

contralateral

septal

deviation.

The

specimens

clearly

show that both septal leaves are present. The body and the anterior columns of the fornices are asymmetrically placed within the larger ventricle, perhaps slightly narrowing the left interventricular foramen and causing mildly increased unilateral ventricular pressure, with resultant asymmetric fusion of the septal leaves. The forniceal asymmetry, however, may merely be a result of the septal deviation. Our data suggest that bowing of the septum pellucidum is a common occurrence and probably represents a benign developmental

CT man

shows

apparent asymmetry of due to orientation of septum pellucidum off midline to left. This finding suggests maId-

frontal

horns

evelopment of septum pellucidum: Lack of one of its two leaves, which should normally fuse at midline during infancy,

prevents

midline

single leaf persists off midline, creating nc ventricle.

fusion,

and a

on one side an asymmet-

Fig. 1.-Axial spin-echo MR image (600/20) shows asymmetry of lateral ventricles caused by deviation of septum pellucidum. At surgery, both

REFERENCES 1 . Williams AL, Haughton VM. Cranial computed Mosby, 1985:317-319 2. Lee SH, Aao KCVG. Cranialcomputed tomography York: McGraw-Hill, 1987:202 3. Silverman FN. Caffey’s pediatric X-ray diagnosis, Year Book Medical, 1985:157-1 61

tomography.

St.

Louis:

and MRI, 2nd ed. New

leaves of septum were present. No obstructing lesion was found at foramen of Monro. Fig.

2.-Pathologic

specimen

from

a person

who

died

of unrelated

causes shows asymmetry of frontal horns of lateral ventricles. Both leaves 8th ed., vol. 1 . Chicago:

of septum pellucidum Angeles, CA.)

are cleariy

present.

(Courtesy

of Hideo

Itabashi,

Los

1176

LETTERS

AJR:158,

May 1992

variant.

Both septal leaves seem to be present in most cases. We one possible explanation for this variant is that the two leaves of the septum pellucidum fuse asymmetrically (possibly because of a mild pressure differential between the two lateral ventrides), such that a bowed, asymmetric septum results. The result is unilateral enlargement of the frontal horn of the lateral ventricle and asymmetry of the fornices, without significant dilatation of the ipsilateral temporal horn. The asymmetry can be pronounced and can simulate unilateral hydrocephalus, but in the absence of dilatation of the temporal horn, it should be recognized as a developmental variant rather than a pathologic condition. We emphasize that when concomitant dilatation of the ipsilateral temporal horn is present, the region of the foramen of Monro should be examined carefully to exclude an obstructing lesion. Congenital webs, stenosis, and tumors of this region have been described [i]. In a symptomatic patient with unilateral ventricular enlargement that includes the temporal horn, explo-

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think

that

ration may be indicated. We compliment interesting variant to our attention.

Dr. Sener

for bringing William

this

P. Dillon

James Barkovich University of California, San Francisco San Francisco, CA 94143-0628 A.

REFERENCE Mampalam

1.

T, Harsh

hydrocephalus

MR Findings Cytomegalovirus A

28-year-old

in adults.

GA, Tien AD, Dillon WP, Wilson Surg Neurol 1991;35: 14-19

in an AIDS Patient Retinitis

Unilateral

with

man with AIDS had had ataxia, decreased A previous

alovirus

in complete

retinitis

had

resulted

episode

vision

in

of cytomeg-

blindness

in the

left

eye despite treatment with ganciclovir. At that time, the right eye was normal. At this admission, with the right eye, the patient could detect gross hand motion only. Funduscopy showed early signs of CMV retinitis. lopathy.

1.-A-D, TI-weighted axial (670/20, A and C) and coronal (500/20, D) MR images in an AIDS patient with cytomegalovirus retinitis. Retinochoroid layer (arrows) of left eye is thickened (A-D) and shows enhancement (C and D) after administration of IV gadopentetate dimeglumine. Fig.

B and

the right eye, and fever for 1 0 days. (CMV)

CB.

Electroencephalographic findings indicated diffuse Axial and coronal Ti -weighted MR images were

encephaobtained.

REFERENCE 1 . Jacobson MA, immunodeficiency

Mills J. Serious cytomegalovirus syndrome (AIDS). Ann Intern

disease in the acquired Med 1988:108:585-594

Unenhanced images showed thickening of the retinochoroid layer of the left eye as compared with that of the right eye (Figs. i A and 1 B). Images obtained after the IV administration of gadopentetate dime-

glumine

showed

enhancement

of the layer in the left eye (Figs.

and 1D). The patient was treated

with ganciclovir,

1C

but his vision did

Pachygyria: We report

not improve.

Cytomegalovirus is one of the most common opportunistic infections in patients with AIDS and is found at autopsy in approximately 90% of AIDS patients [1]. Although often asymptomatic, CMV infections can cause significant morbidity and mortality. Retinitis is one of the most common manifestations of CMV infection; it causes de-

characterized

creased

subarachnoid

visual

acuity

and

may

aminations show small, white, to form fluffy, white exudates.

lead

to

granular Clinical

blindness.

Funduscopic

ex-

retinal lesions that coalesce diagnosis of CMV retinitis is

CT Findings a case of pachygyria, by abnormal

a rare congenital

gyral development

in which

malformation a few, coarse,

broad gyri are separated by a decreased number of sulci. The patient was a 6-month-old neonate with seizures, psychomotor retardation, and failure to thrive. CT showed multiple broad gyri separated by a few sulci throughout the anterior half of the brain and widened space

(Fig. 1). An unusual

ventricular

evident: absence of the septum pellucidum, horns

separated

by medially

located

configuration

was

small and parallel frontal

abnormal

gyri, and widely

sep-

based on funduscopic findings and recovery of the virus from any body site [i]. So far, radiology has had no definite role in the diagnosis

arated tubular bodies of the lateral ventricles.

The separation

frontal

ventricles

of CMV

dysgenesis of the corpus callosum. The falx was present. Pachygyria may be localized to a small area of the brain, or it may involve a large portion. Extreme pachygyria is termed agyria or

retinitis

or in the follow-up

of these

patients.

Although

MR

findings at various stages of CMV retinitis have not been described, our case suggests that enhancement of the retinochoroid layer is a late finding. Robert J. Monette David J. Czarnecki Brian P. Buggy

St. Luke’s Medical Center Milwaukee, WI 53215

horns

lissencephaly

and

the

(smooth

bodies

brain);

of the

lateral

the cortical

surface

of the

suggested

is totally

agyrial

except for a wide, shallow sylvian fissure. Pachygyria without associated areas of agyria usually causes less severe clinical manifestations than agyria does and is considered a separate entity [i -6]. Pachygyria is a hereditary (autosomal recessive) disorder of sulcation

and migration.

Neurons

fail to migrate

from the periventricular

AJR:158,

1177

LETTERS

May 1992

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Accompanying

anomalies

are

schizencephaly,

polymicrogyria,

and

heterotopic gray matter [i -6]. The CT findings in pachygyria have recently been described [i -4]: broad gyri; a wide, shallow sylvian fissure; wide subarachnoid space; enlarged ventricles with colpocephaly; calcification in the septum pellucidum; and sparse white matter. Diagnosis of pachygyria based on CT findings can be difficult in premature infants because on CT scans the surface of the brain appears to be smoother in premature infants than in full-term neonates [5]. Also, it is difficult to detect schizencephaly (in fused-lip form), polymicrogyria, and heterotopic gray matter on CT scans [6]. MR is the best technique for evaluation of such disorders of sulcation and migration, especially in cases in which the CT findings are equivocal. This contrast

case illustrates the typical CT findings of pachygyria. In to previous observations, wide sylvian fissures and enlarged

ventricles were not seen. Instead, the septum pellucidum was absent, and dysgenesis of the corpus callosum was present. The unusual ventricular configuration might reflect a primary error in ventricular morphogenesis

or might

with surrounding

be due

abnormal

to dysgenesis

of the corpus

callosum

gyria. R. Nun Sener

Aynur

Dagdeviren Rahmi

Akyol

and colleagues Hospital

of Ege

University

Bornova, lzmir, Turkey Fig. 1.-CT scans show pachygyria throughout anterior halves of cerebral hemispheres adjacent to widened subarachnoid spaces. A, Scan through pens shows bilateral thickened temporal gyn. B, Scan through thalami shows pachygyria of frontal and parietal lobes. Frontal lobes of lateral ventricles are small and have an unusual parallel configuration (arrows). Abnormal gyri extend from anterior frontal lobe to medial surfaces of frontal horns, which show no evidence of indentation of heads of caudate nuclei. Sylvian fissures are not detectable except for

REFERENCES 1 . Byrd

a shallow, narrow sulcus on left. Thalami appear normal. C, Scan

shows

tubular

shape

of bodies

of lateral

ventricles,

which

are

widely separated appearance and absence

and are converging anterioriy. This finding along with of frontal horns (B) suggests dysgenesis of corpus callosum of septum

normal

of cerebral

formation

TP, Naidich

TP. The CT and MR evaluation

Garcia CA, Dunn D, Trevor A. The lissencephaly (agyria) syndrome in siblings: computed tomographic and neuropathological findings. Arch Neurol 1978:35:608-611 5. Williams AL, Haughton vM. Cranial computed tomography. St. Louis: Mosby, 1985:348 6. Latchaw RE. Computed tomography of the head, neck, and spine. Chicago: Year Book Medical, 1985:473-474 4.

and cerebellar

cortical

development,

of gyri and sulci and hypoplasia

Letters

RE, Bohan

92-95

pellucidum.

germinal matrix to the cortical surface of the brain during the period of normal gyral formation at 26-28 weeks of gestation. The result is

cessation

SE, Osbom

of migrational disorders of the brain. Part I. Lissencephaly and pachygyria. Pediatr Radio! 1989:19:151-156 2. Williams JP, Joslyn JN. Lissencephaly: computed tomographic diagnosis. CT 1983;7:141-144 3. Ohno K, Enomoto T, Imamoto J, Takeshila K, Arima M. Lissencephaly (agyria) on computed tomography. J Comput Assist Tomogr 1979:3:

are published

with ab-

of the white matter.

at the discretion

of the Editor

and are subject

to editing.

Letters to the Editor must not be more than two double-spaced, typewritten pages. One or two figures may be included. Abbreviations should not be used. Limit the number of authors to four, or we will list only the first three and add “and colleagues” to the end of the list. See Author Guidelines.

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